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1.  Midazolam Premedication in Children: A Pilot Study Comparing Intramuscular and Intranasal Administration 
Anesthesia Progress  2005;52(2):56-61.
The purpose of this study was to compare the effectiveness of intramuscular and intranasal midazolam used as a premedication before intravenous conscious sedation. Twenty-three children who were scheduled to receive dental treatment under intravenous sedation participated. The patients ranged in age from 2 to 9 years (mean age, 5.13 years) and were randomly assigned to receive a dose of 0.2 mg/kg of midazolam premedication via either intramuscular or intranasal administration. All patients received 50% nitrous oxide and 50% oxygen inhalation sedation and local anesthetic (0.2 mL of 4% prilocaine hydrochloride) before venipuncture. The sedation level, movement, and crying were evaluated at the following time points: 10 minutes after drug administration and at the times of parental separation, passive papoose board restraint, nitrous oxide nasal hood placement, local anesthetic administration, and initial venipuncture attempt. Mean ratings for the behavioral parameters of sedation level, degree of movement, and degree of crying were consistently higher but not significant in the intramuscular midazolam group at all 6 assessment points. Intramuscular midazolam was found to be statistically more effective in providing a better sedation level and less movement at the time of venipuncture than intranasal administration. Our findings indicate a tendency for intramuscular midazolam to be more effective as a premedication before intravenous sedation.
doi:10.2344/0003-3006(2005)52[56:MPICAP]2.0.CO;2
PMCID: PMC2527044  PMID: 16048152
Midazolam; Dentistry; Sedation; Pediatrics; Intramuscular; Intranasal
2.  Carbon dioxide accumulation during analgosedated colonoscopy: Comparison of propofol and midazolam 
AIM: To characterize the profiles of alveolar hypoventilation during colonoscopies performed under sedoanalgesia with a combination of alfentanil and either midazolam or propofol.
METHODS: Consecutive patients undergoing routine colonoscopy were randomly assigned to sedation with either propofol or midazolam in an open-labeled design using a titration scheme. All patients received 4 μg/kg per body weight alfentanil for analgesia and 3 L of supplemental oxygen. Oxygen saturation (SpO2) was measured by pulse oximetry (POX), and capnography (PcCO2) was continuously measured using a combined dedicated sensor at the ear lobe. Instances of apnea resulting in measures such as stimulation of the patient, a chin lift, a mask maneuver, or withholding of sedation were recorded. PcCO2 values (as a parameter of sedation-induced hypoventilation) were compared between groups at the following distinct time points: baseline, maximal rise, termination of the procedure and 5 min after termination of the procedure. The number of patients in both study groups who regained baseline PcCO2 values (± 1.5 mmHg) five minutes after the procedure was determined.
RESULTS: A total of 97 patients entered this study. The data from 14 patients were subsequently excluded for clinical procedure-related reasons or for technical problems. Therefore, 83 patients (mean age 62 ± 13 years) were successfully randomized to receive propofol (n = 42) or midazolam (n = 41) for sedation. Most of the patients were classified as American Society of Anesthesiologists (ASA) II [16 (38%) in the midazolam group and 15 (32%) in the propofol group] and ASA III [14 (33%) and 13 (32%) in the midazolam and propofol groups, respectively]. A mean dose of 5 (4-7) mg of IV midazolam and 131 (70-260) mg of IV propofol was used during the procedure in the corresponding study arms. The mean SpO2 at baseline (%) was 99 ± 1 for the midazolam group and 99 ± 1 for the propofol group. No cases of hypoxemia (SpO2 < 85%) or apnea were recorded. However, an increase in PcCO2 that indicated alveolar hypoventilation occurred in both groups after administration of the first drug and was not detected with pulse oximetry alone. The mean interval between the initiation of sedation and the time when the PcCO2 value increased to more than 2 mmHg was 2.8 ± 1.3 min for midazolam and 2.8 ± 1.1 min for propofol. The mean maximal rise was similar for both drugs: 8.6 ± 3.7 mmHg for midazolam and 7.4 ± 3.2 mmHg for propofol. Five minutes after the end of the procedure, the mean difference from the baseline values was significantly lower for the propofol treatment compared with midazolam (0.9 ± 3.0 mmHg vs 4.3 ± 3.7 mmHg, P = 0.0000169), and significantly more patients in the propofol group had regained their baseline value ± 1.5 mmHg (32 of 41 vs 12 of 42, P = 0.0004).
CONCLUSION: A significantly higher number of patients sedated with propofol had normalized PcCO2 values five minutes after sedation when compared with patients sedated with midazolam.
doi:10.3748/wjg.v18.i38.5389
PMCID: PMC3471107  PMID: 23082055
Colonoscopy; Deep sedation; Propofol; Hypoventilation; Blood gas monitoring; Transcutaneous
3.  Drugs Used for Parenteral Sedation in Dental Practice 
Anesthesia Progress  1988;35(5):199-205.
The relative efficacy and safety of drugs and combinations used clinically in dentistry as premedicants to alleviate patient apprehension are largely unsubstantiated. To evaluate the efficacy and safety of agents used for parenteral sedation through controlled clinical trials, it is first necessary to identify which drugs, doses, and routes of administration are actually used in practice. A survey instrument was developed to characterize the drugs used clinically for anesthesia and sedation by dentists with advanced training in pain control. A random sample of 500 dentists who frequently use anesthesia and sedation in practice was selected from the Fellows of the American Dental Society of Anesthesiology. The first mailing was followed by a second mailing to nonrespondents after 30 days. The respondents report a variety of parenteral sedation techniques in combination with local anesthesia (the response categories are not mutually exclusive): nitrous oxide (64%), intravenous conscious sedation (59%), intravenous “deep” sedation (47%), and outpatient general anesthesia (27%). Drugs most commonly reported for intravenous sedation include diazepam, methohexital, midazolam, and combinations of these drugs with narcotics. A total of 82 distinct drugs and combinations was reported for intravenous sedation and anesthesia. Oral premedication and intramuscular sedation are rarely used by this group. Most general anesthesia reported is done on an outpatient basis in private practice. These results indicate that a wide variety of drugs is employed for parenteral sedation in dental practice, but the most common practice among dentists with advanced training in anesthesia is local anesthesia supplemented with intravenous sedation consisting of a benzodiazepine and an opioid or a barbiturate.
PMCID: PMC2167868  PMID: 3250279
4.  Comparison between the recovery time of alfentanil and fentanyl in balanced propofol sedation for gastrointestinal and colonoscopy: a prospective, randomized study 
BMC Gastroenterology  2012;12:164.
Background
There is increasing interest in balanced propofol sedation (BPS) titrated to moderate sedation (conscious sedation) for endoscopic procedures. However, few controlled studies on BPS targeted to deep sedation for diagnostic endoscopy were found. Alfentanil, a rapid and short-acting synthetic analog of fentanyl, appears to offer clinically significant advantages over fentanyl during outpatient anesthesia.
It is reasonable to hypothesize that low dose of alfentanil used in BPS might also result in more rapid recovery as compared with fentanyl.
Methods
A prospective, randomized and double-blinded clinical trial of alfentanil, midazolam and propofol versus fentanyl, midazolam and propofol in 272 outpatients undergoing diagnostic esophagogastroduodenal endoscopy (EGD) and colonoscopy for health examination were enrolled. Randomization was achieved by using the computer-generated random sequence. Each combination regimen was titrated to deep sedation. The recovery time, patient satisfaction, safety and the efficacy and cost benefit between groups were compared.
Results
260 participants were analyzed, 129 in alfentanil group and 131 in fentanyl group. There is no significant difference in sex, age, body weight, BMI and ASA distribution between two groups. Also, there is no significant difference in recovery time, satisfaction score from patients, propofol consumption, awake time from sedation, and sedation-related cardiopulmonary complications between two groups. Though deep sedation was targeted, all cardiopulmonary complications were minor and transient (10.8%, 28/260). No serious adverse events including the use of flumazenil, assisted ventilation, permanent injury or death, and temporary or permanent interruption of procedure were found in both groups. However, fentanyl is New Taiwan Dollar (NT$) 103 (approximate US$ 4) cheaper than alfentanil, leading to a significant difference in total cost between two groups.
Conclusions
This randomized, double-blinded clinical trial showed that there is no significant difference in the recovery time, satisfaction score from patients, propofol consumption, awake time from sedation, and sedation-related cardiopulmonary complications between the two most common sedation regimens for EGD and colonoscopy in our hospital. However, fentanyl is NT$103 (US$ 4) cheaper than alfentanil in each case.
Trial registration
Institutional Review Board of Buddhist Tzu Chi General Hospital (IRB097-18) and Chinese Clinical Trial Registry (ChiCTR-TRC-12002575)
doi:10.1186/1471-230X-12-164
PMCID: PMC3607964  PMID: 23170921
Balanced propofol sedation; Alfentanil; Fentanyl; Deep sedation; Diagnostic endoscopy; Cost benefit
5.  An Evaluation of Intranasal Sufentanil and Dexmedetomidine for Pediatric Dental Sedation 
Pharmaceutics  2014;6(1):175-184.
Conscious or moderate sedation is routinely used to facilitate the dental care of the pre- or un-cooperative child. Dexmedetomidine (DEX) has little respiratory depressant effect, possibly making it a safer option when used as an adjunct to either opioids or benzodiazepines. Unlike intranasal (IN) midazolam, IN application of DEX and sufentanil (SUF) does not appear to cause much discomfort. Further, although DEX lacks respiratory depressive effects, it is an α2-agonist that can cause hypotension and bradycardia when given in high doses or during prolonged periods of administration. The aim of this feasibility study was to prospectively assess IN DEX/SUF as a potential sedation regimen for pediatric dental procedures. After IRB approval and informed consent, children (aged 3–7 years; n = 20) from our dental clinic were recruited. All patients received 2 μg/kg (max 40 μg) of IN DEX 45 min before the procedure, followed 30 min later by 1 μg/kg (max 20 μg) of IN SUF. An independent observer rated the effects of sedation using the Ohio State University Behavior Rating Scale (OSUBRS) and University of Michigan Sedation Scale (UMSS). The dentist and the parent also assessed the efficacy of sedation. Dental procedures were well tolerated and none were aborted. The mean OSUBRS procedure score was 2.1, the UMSS procedure score was 1.6, and all scores returned to baseline after the procedure. The average dentist rated quality of sedation was 7.6 across the 20 subjects. After discharge, parents reported one child with prolonged drowsiness and one child who vomited at home. The use of IN DEX supplemented with IN SUF provided both an effective and tolerable form of moderate sedation. Although onset and recovery are slower than with oral (PO) midazolam and transmucosal fentanyl, the quality of the sedation may be better with less risk of respiratory depression. Results from this preliminary study showed no major complications from IN delivery of these agents.
doi:10.3390/pharmaceutics6010175
PMCID: PMC3978530  PMID: 24662315
pediatric sedation; pediatric dentistry; intranasal drug administration
6.  Intravenous ketamine plus midazolam is superior to intranasal midazolam for emergency paediatric procedural sedation 
Objectives—This study compared intranasal midazolam (INM) with a combination of intravenous ketamine and intravenous midazolam (IVKM) for sedation of children requiring minor procedures in the emergency department.
Method—A single blinded randomised clinical trial was conducted in the emergency department of a major urban paediatric hospital. Subjects requiring sedation for minor procedures were randomised to receive either INM (0.4 mg/kg) or intravenous ketamine (1 mg/kg) plus intravenous midazolam (0.1 mg/kg). Physiological variables and two independent measures of sedation (Sedation Score and Visual Analogue Sedation Scale) were recorded before sedation and at regular intervals during the procedure and recovery period. Times to adequate level of sedation and to discharge were compared.
Results—Fifty three patients were enrolled over a 10 month period. Sedation was sufficient to complete the procedures in all children receiving IVKM and in 24 of the 26 receiving INM. Onset of sedation was an average of 5.3 minutes quicker with IVKM than with INM (95%CI 3.2, 7.4 minutes, p<0.001). Children given INM were discharged an average of 19 minutes earlier than those given IVKM (95%CI 4, 33 minutes, p=0.02). Mean Sedation Scores and Visual Analogue Sedation Scale scores for the 30 minutes after drug administration were significantly better in children given IVKM compared with INM (2.4 and 1.8 versus 3.5 and 3.8, respectively). Both doctors and parents were more satisfied with sedation by intravenous ketamine and midazolam.
Conclusions—Intravenous ketamine plus midazolam used in an appropriate setting by experienced personnel provides an excellent means of achieving sedation suitable for most non-painful minor procedures for children in the emergency department. This combination is superior to INM in terms of speed of onset and consistency of effect. INM delivered via aerosol spray has a more variable effect but may still be adequate for the completion of many of these procedures.
doi:10.1136/emj.18.1.39
PMCID: PMC1725505  PMID: 11310461
7.  Comparison of dexmedetomidine and midazolam for monitored anesthesia care combined with tramadol via patient-controlled analgesia in endoscopic nasal surgery: A prospective, randomized, double-blind, clinical study 
Abstract
Background
Monitored anesthesia care (MAC) may be applied for septoplasty or endoscopic sinus surgery in which an adequate sedation and analgesia without respiratory depression are desired for comfort of both the patient and the surgeon. Several combinations with different agents have been used for this purpose in these patients. However, analgesic properties for these agents have not been reported.
Objective
The aim of this study was to investigate the analgesic and sedative effects of dexmedetomidine or midazolam infusion combined with tramadol that was used via patient-controlled analgesia (PCA), and to document the effects of these drugs on early cognitive functions.
Methods
This prospective, randomized, double-blind, clinical study enrolled patients undergoing septoplasty or endoscopic sinus surgery at the Abant Izzet Baysal University Hospital, Bolu, Turkey, between February and September 2006. Patients were randomly allocated in a 1:1 ratio into 1 of 2 groups: the dexmedetomidine group (group D) patients received IV dexmedetomidine 1 μg/kg for 10 minutes followed by continuous infusion of 0.5 μg/kg · h−1; and the midazolam group (group M) patients were administered a loading dose of IV midazolam 40 μg/kg for 10 minutes followed by infusion at the rate of 50 μg/kg · h−1. A 1-minute bolus dose of IV tramadol (1.5 mg/kg) was administered in both groups 10 minutes after the administration of the primary drug, and continued via infusion using a PCA device. After baseline measurements, systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), heart rate (HR), oxygen saturation, and rate of respiration were recorded after the loading dose of study drug, after the bolus tramadol dose, at 10-minute intervals during the operation, and twice in the recovery rooms; 5 minutes after arrival and 5 minutes before discharge. Verbal rating score (VRS) and Ramsay sedation score were determined at baseline (after surgery was started), every 10 minutes thereafter until the end of the operation, and 2 times during recovery. All patients were assessed with the Wechsler Memory Scale-Revised at baseline (preoperatively) and 4 hours after the operation.
Results
Seventy patients were enrolled in the study and randomly assigned to 1 of 2 groups: group D (sex, male/female, 23/12; mean [SEM] age, 32.53 [2.07] years; mean [SEM] weight, 73.03 [2.41] kg) or group M (sex, male/female, 21/14; mean [SEM] age, 34.43 [1.83] years; mean [SEM] weight, 67.90 [2.32] kg). All hemodynamic parameters (SAP, DAP, MAP, HR) were significantly higher in group M compared with group D from the onset of the surgery to discharge time (P < 0.05). Pain and sedation scores were similar in both groups, but the amount of PCA-administered rescue tramadol was significantly higher in group M (P = 0.001). A higher, though not statistically significant, prevalence of adverse events (ie, hypotension, bradycardia, and perioperative nausea and vomiting) were observed in group D. Postoperative logical verbal memory and digit span values were significantly higher in group D when compared with group M (P < 0.05). Postoperative digit span and visual reproduction scores were significantly higher than preoperative values in group D (P < 0.05). Postoperative personality functioning scores were significantly higher than preoperative values in group M (P < 0.05).
Conclusions
Based on VRS, Ramsay sedation scores, and surgeon and anesthesiologist satisfaction scores, dexmedetomidine or midazolam combined with tramadol PCA provided adequate analgesia and sedation in these adult patients undergoing septoplasty or endoscopic sinus surgery with MAC. A significantly larger amount of rescue tramadol was used by group M, suggesting that a better analgesic effect was achieved with dexmedetomidine.
doi:10.1016/j.curtheres.2007.04.001
PMCID: PMC3965987  PMID: 24678121
dexmedetomidine; midazolam; sedoanalgesia; cognitive function
8.  A prospective study of high dose sedation for rapid tranquilisation of acute behavioural disturbance in an acute mental health unit 
BMC Psychiatry  2013;13:225.
Background
Acute behavioural disturbance (ABD) is a common problem in psychiatry and both physical restraint and involuntary parenteral sedation are often required to control patients. Although guidelines are available, clinical practice is often guided by experience and there is little agreement on which drugs should be first-line treatment for rapid tranquilisation. This study aimed to investigate sedation for ABD in an acute mental healthcare unit, including the effectiveness and safety of high dose sedation.
Methods
A prospective study of parenteral sedation for ABD in mental health patients was conducted from July 2010 to June 2011. Drug administration (type, dose, additional doses), time to sedation, vital signs and adverse effects were recorded. High dose parenteral sedation was defined as greater than the equivalent of 10 mg midazolam, droperidol or haloperidol (alone or in combination), compared to patients receiving 10 mg or less (normal dose). Effective sedation was defined as a fall in the sedation assessment tool score by two or a score of zero or less. Outcomes included frequency of adverse drug effects, time to sedation/tranquilisation and use of additional sedation.
Results
Parenteral sedation was given in 171 cases. A single drug was given in 96 (56%), including droperidol (74), midazolam (19) and haloperidol (3). Effective sedation occurred in 157 patients (92%), and the median time to sedation was 20 min (Range: 5 to 100 min). The median time to sedation for 93 patients receiving high dose sedation was 20 min (5-90 min) compared to 20 min (5-100 min; p = 0.92) for 78 patients receiving normal dose sedation. Adverse effects occurred in 16 patients (9%); hypotension (14), oxygen desaturation (1), hypotension and oxygen desaturation (1). There were more adverse effects in the high dose sedation group compared to the normal dose group [11/93 (12%) vs. 5/78 (6%); p = 0.3]. Additional sedation was given in 9 of 171 patients (5%), seven in the high dose and two in the normal dose groups.
Conclusions
Large initial doses of sedative drugs were used for ABD in just over half of cases and additional sedation was uncommon. High dose sedation did not result in more rapid or effective sedation but was associated with more adverse effects.
doi:10.1186/1471-244X-13-225
PMCID: PMC3848824  PMID: 24044673
Violence; Sedation; Acute psychiatric unit; Droperidol; Benzodiazepine; Antipsychotic
9.  Risk Factors With Intravenous Sedation for Patients With Disabilities 
Anesthesia Progress  2013;60(4):153-161.
The purpose of this study was to identify the risk factors associated with low peripheral oxygen saturation (SpO2) and delayed recovery of dental patients with disabilities after intravenous sedation. A total of 1213 patients with disabilities were retrospectively investigated with respect to demographic parameters and sedation conditions. Multivariate logistic analyses were conducted for patients with an SpO2 <90% and a recovery period of >60 minutes to identify the risk factors for poor sedation conditions. A significant odds ratio related to decreased SpO2 was observed for age, sex, midazolam and propofol levels, concurrent use of nitrous oxide, cerebral palsy, Down syndrome, and mental retardation. The most problematic patients were those diagnosed with Down syndrome (odds ratio, 3.003–7.978; 95% confidence interval; P < .001). Decision tree analysis showed an increased risk of decreased SpO2 in males with Down syndrome or after administration of >0.493 mg/kg propofol in combination with midazolam. An increased risk of delayed awakening was seen in patients aged less than 21 years and in males administered >0.032 mg/kg of midazolam. Intravenous sedation for dental patients with disabilities, particularly those with cerebral palsy, Down syndrome, or mental retardation, increases the risk of decreased SpO2. In addition, delayed recovery is expected after midazolam administration.
doi:10.2344/0003-3006-60.4.153
PMCID: PMC3891456  PMID: 24423418
Dental sedation; Low peripheral oxygen saturation; Delayed recovery
10.  Timing and side effects of flumazenil for dental outpatients receiving intravenous sedation with midazolam. 
Anesthesia Progress  1997;44(4):127-131.
We studied the timing and side effects of flumazenil treatment for 10 healthy volunteers and 46 dental outpatients who received intravenous sedation with midazolam. For the volunteers, vital signs were monitored before and after intravenous injection of midazolam and flumazenil. In addition, grip strength, signs and symptoms, and performance on the Romberg's test and addition tests were evaluated 30 min and 60 min after midazolam injection as well as after flumazenil injection. There were no significant changes in vital signs before, immediately after, or 50 min after injection of flumazenil, the latter time corresponding to the half-life of the drug. Thus, awakening from sedation was associated with no effects on the cardiovascular or respiratory systems. Distinct effects of flumazenil were demonstrated by the Romberg's test and the assessment of sedation status. Flumazenil had no effect on the outcome of the addition test. For the outpatients, sedation status and signs and symptoms were studied in patients undergoing procedures lasting 30 min or less (group S) and those undergoing procedures lasting 31 to 60 min (group L). Three patients in group S and one in group L had signs and symptoms of resedation. After treatment with flumazenil, abnormalities such as excitability and nausea were reported by only two patients in group L. One patient in group S had drowsiness that did not resolve after injection of flumazenil and continued until the following day. Our results indicate that flumazenil should be given at least 60 min after intravenous sedation with midazolam in dental outpatients. Moreover, caution should be exercised with regard to the potential side effects of flumazenil.
PMCID: PMC2148936  PMID: 9481956
11.  A Randomized Double-Blind Pilot Study to Compare Conscious Sedation Produced by Diazepam Against Sufentanil 
Anesthesia Progress  1987;34(4):137-141.
Intravenous sufentanil, an analog of fentanyl, was compared to diazepam for conscious sedation in ambulatory dental outpatients. Ten patients undergoing the surgical removal of impacted third molars served as subjects in a double-blind, within-subject, single crossover study. Sedation was achieved with a combination of 30% nitrous oxide/70% oxygen by nasal mask and either diazepam (0.05—0.15 mg/kg) or sufentanic (0.05—0.15 μg/kg) titrated to a clinical endpoint of altered speech and relaxation. Intraoperative physiologic monitoring, patients' and the oral surgeon's subjective estimates of efficacy and psychomotor recovery were used to compare the two treatments. Both patients (eight of 10) and surgeons (six of 10) preferred sufentanil sedation. No significant differences were noted between treatments for psychomotor recovery. These preliminary data in a small sample suggest that sufentanil produces adequate conscious sedation in dental outpatients and should be evaluated further with larger patient samples.
PMCID: PMC2186288  PMID: 2964215
12.  Efficiency and safety of inhalative sedation with sevoflurane in comparison to an intravenous sedation concept with propofol in intensive care patients: study protocol for a randomized controlled trial 
Trials  2012;13:135.
Background
State of the art sedation concepts on intensive care units (ICU) favor propofol for a time period of up to 72 h and midazolam for long-term sedation. However, intravenous sedation is associated with complications such as development of tolerance, insufficient sedation quality, gastrointestinal paralysis, and withdrawal symptoms including cognitive deficits. Therefore, we aimed to investigate whether sevoflurane as a volatile anesthetic technically implemented by the anesthetic-conserving device (ACD) may provide advantages regarding ‘weaning time’, efficiency, and patient’s safety when compared to standard intravenous sedation employing propofol.
Method/Design
This currently ongoing trial is designed as a two-armed, monocentric, randomized prospective phase II study including intubated intensive care patients with an expected necessity for sedation exceeding 48 h. Patients are randomly assigned to either receive intravenous sedation with propofol or sevoflurane employing the ACD. Primary endpoint is the comparison of the ‘weaning time’ defined as the time required from discontinuation of the sedating agent until sufficient spontaneous breathing occurs. Moreover, sedation depth evaluated by Richmond Agitation Sedation Scale and parameters of patient’s safety (that is, vital signs, laboratory monitoring of organ function) as well as the duration of mechanical ventilation and overall stay on the ICU are analyzed and compared. An intention-to-treat analysis will be carried out with all patients for whom it will be possible to define a wake-up time. In addition, a per-protocol analysis is envisaged. Completion of patient recruitment is expected by the end of 2012.
Discussion
This clinical study is designed to evaluate the impact of sevoflurane during long-term sedation of critically ill patients on ‘weaning time’, efficiency, and patient’s safety compared to the standard intravenous sedation concept employing propofol.
Trial registration
EudraCT2007-006087-30; ISCRTN90609144
doi:10.1186/1745-6215-13-135
PMCID: PMC3502585  PMID: 22883020
Inhalative sedation; Intravenous sedation; Intensive care; Sevoflurane
13.  Arousal time from sedation during spinal anaesthesia for elective infraumbilical surgeries: Comparison between propofol and midazolam 
Indian Journal of Anaesthesia  2014;58(4):403-409.
Background and Aims:
Studies have already compared propofol and midazolam as sedatives during regional anaesthesia. A few studies have focused on recovery characteristics and very few have utilised both instrumental and clinical sedation monitoring for assessing recovery time. This study was designed primarily to compare arousal time from sedation using propofol with that of midazolam during spinal anaesthesia for infraumbilical surgeries, while depth of sedation was monitored continuously with bispectral index (BIS) monitor. The correlation between the BIS score and observer's assessment of awareness/sedation (OAA/S) score during recovery from sedation was also studied.
Methods:
A total of 110 patients were randomly assigned to receive either propofol (Group P, n = 55) or midazolam (Group M, n = 55). Patients in the Group P received bolus of propofol (1 mg/kg), followed by infusion at 3 mg/kg/h; Group M received bolus of midazolam (0.05 mg/kg), followed by infusion at 0.06 mg/kg/h and titration until BIS score 70 was achieved and maintained between 65 and 70. OAA/S score was noted at BIS 70 and again at BIS 90 during recovery. The time to achieve OAA/S score 5 was noted. Spearman's correlation was calculated between the arousal time from sedation and the time taken to reach an OAA/S score of 5 in both the study groups.
Results:
Arousal time from sedation was found lower for Group P compared to Group M (7.54 ± 3.70 vs. 15.54 ± 6.93 min, respectively, P = 0.000). The time taken to reach OAA/S score 5 was also found to be lower for Group P than Group M (6.81 ± 2.54 min vs. 13.51 ± 6.24 min, respectively, P = 0.000).
Conclusion:
A shorter arousal time from sedation during spinal anaesthesia can be achieved using propofol compared with midazolam, while depth of sedation was monitored with BIS monitor and OAA/S score. Both objective and clinical scoring correlate strongly during recovery from sedation.
doi:10.4103/0019-5049.138972
PMCID: PMC4155284  PMID: 25197107
Bispectral index monitoring; midazolam; propofol; sedation; spinal anaesthesia
14.  Sedative Efficacy of Propofol in Patients Intubated/Ventilated after Coronary Artery Bypass Graft Surgery 
Background:
Sedation after open heart surgery is important in preventing stress on the heart. The unique sedative features of propofol prompted us to evaluate its potential clinical role in the sedation of post-CABG patients.
Objectives:
To compare propofol-based sedation to midazolam-based sedation after coronary artery bypass graft (CABG) surgery in the intensive care unit (ICU).
Patients and Methods:
Fifty patients who were admitted to the ICU after CABG surgery was randomized into two groups to receive sedation with either midazolam or propofol infusions; and additional analgesia was administered if required. Inclusion criteria were as follows: patients 40-60 years old, hemodynamic stability, ejection fraction (EF) more than 40%; exclusion criteria included patients who required intra-aortic balloon pump or inotropic drugs post-bypass. The same protocol of anesthetic medications was used in both groups. Depth of sedation was monitored using the Ramsay sedation score (RSS). Invasive mean arterial pressure (MAP) and heart rate (HR), arterial blood gas (ABG) and ventilatory parameters were monitored continuously after the start of study drug and until the patients were extubated.
Results:
The depth of sedation was almost the same in the two groups (RSS=4.5 in midazolam group vs 4.7 in propofol group; P = 0.259) but the total dose of fentanyl in the midazolam group was significantly more than the propofol group (12.5 mg/hr vs 4 mg/hr) (P = 0.0039). No significant differences were found in MAP (P = 0.51) and HR (P = 0.41) between the groups. The mean extubation time in patients sedated with propofol was shorter than those sedated with midazolam (102 ± 27 min vs 245 ± 42 min, respectively; P < 0.05) but the ICU discharge time was not shorter (47.5 hr vs 36.3 hr, respectively; P = 0.24).
Conclusions:
Propofol provided a safe and acceptable sedation for post-CABG surgical patients, significantly reduced the requirement for analgesics, and allowed for more rapid tracheal extubation than midazolam but did not result in earlier ICU discharge.
doi:10.5812/aapm.17109
PMCID: PMC3961039  PMID: 24660162
Propofol; Analgesics; Coronary Artery Bypass; Deep Sedation; Midazolam; Airway Extubation; Length of Stay
15.  Average recovery time from a standardized intravenous sedation protocol and standardized discharge criteria in the general dental practice setting. 
Anesthesia Progress  2002;49(3):77-81.
Intravenous sedation has been used in dentistry for many years because of its perceived advantages over general anesthesia, including shorter recovery times. However, there is limited literature available on recovery from intravenous dental sedation, particularly in the private general practice setting. The aim of this study was to describe the recovery times when sedation was conducted in private dental practice and to consider this in relation to age, weight, procedure type, and procedure time. The data were extracted from the intravenous sedation records available with 1 general anesthesia-trained dental practitioner who provides ambulatory sedation services to a number of private general dental practices in the Perth, Western Australia Metropolitan Area. Standardized intravenous sedation techniques as well as clear standardized discharge criteria were utilized. The sedatives used were fentanyl, midazolam, and propofol. Results from 85 patients produced an average recovery time of 19 minutes. Recovery time was not associated with the type or length of dental procedures performed.
PMCID: PMC2007342  PMID: 15384295
16.  Propofol versus Midazolam for Sedation during Esophagogastroduodenoscopy in Children 
Clinical Endoscopy  2013;46(4):368-372.
Background/Aims
To evaluate the efficacy and safety of propofol and midazolam for sedation during esophagogastroduodenoscopy (EGD) in children.
Methods
We retrospectively reviewed the hospital records of 62 children who underwent ambulatory diagnostic EGD during 1-year period. Data were collected from 34 consecutive patients receiving propofol alone. Twenty-eight consecutive patients who received sedation with midazolam served as a comparison group. Outcome variables were length of procedure, time to recovery and need for additional supportive measures.
Results
There were no statistically significant differences between the two groups in age, weight, sex, and the length of endoscopic procedure. The recovery time from sedation was markedly shorter in propofol group (30±16.41 minutes) compared with midazolam group (58.89±17.32 minutes; p<0.0001). During and after the procedure the mean heart rate was increased in midazolam group (133.04±19.92 and 97.82±16.7) compared with propofol group (110.26±20.14 and 83.26±12.33; p<0.0001). There was no localized pain during sedative administration in midazolam group, though six patients had localized pain during administration of propofol (p<0.028). There was no serious major complication associated with any of the 62 procedures.
Conclusions
Intravenous administered propofol provides faster recovery time and similarly safe sedation compared with midazolam in pediatric patients undergoing upper gastrointestinal endoscopy.
doi:10.5946/ce.2013.46.4.368
PMCID: PMC3746141  PMID: 23964333
Propofol; Midazolam; Endoscopy, digestive system; Child
17.  Deep sedation during gastrointestinal endoscopy: Propofol-fentanyl and midazolam-fentanyl regimens 
AIM: To compare deep sedation with propofol-fentanyl and midazolam-fentanyl regimens during upper gastrointestinal endoscopy.
METHODS: After obtaining approval of the research ethics committee and informed consent, 200 patients were evaluated and referred for upper gastrointestinal endoscopy. Patients were randomized to receive propofol-fentanyl or midazolam-fentanyl (n = 100/group). We assessed the level of sedation using the observer’s assessment of alertness/sedation (OAA/S) score and bispectral index (BIS). We evaluated patient and physician satisfaction, as well as the recovery time and complication rates. The statistical analysis was performed using SPSS statistical software and included the Mann-Whitney test, χ2 test, measurement of analysis of variance, and the κ statistic.
RESULTS: The times to induction of sedation, recovery, and discharge were shorter in the propofol-fentanyl group than the midazolam-fentanyl group. According to the OAA/S score, deep sedation events occurred in 25% of the propofol-fentanyl group and 11% of the midazolam-fentanyl group (P = 0.014). Additionally, deep sedation events occurred in 19% of the propofol-fentanyl group and 7% of the midazolam-fentanyl group according to the BIS scale (P = 0.039). There was good concordance between the OAA/S score and BIS for both groups (κ = 0.71 and κ = 0.63, respectively). Oxygen supplementation was required in 42% of the propofol-fentanyl group and 26% of the midazolam-fentanyl group (P = 0.025). The mean time to recovery was 28.82 and 44.13 min in the propofol-fentanyl and midazolam-fentanyl groups, respectively (P < 0.001). There were no severe complications in either group. Although patients were equally satisfied with both drug combinations, physicians were more satisfied with the propofol-fentanyl combination.
CONCLUSION: Deep sedation occurred with propofol-fentanyl and midazolam-fentanyl, but was more frequent in the former. Recovery was faster in the propofol-fentanyl group.
doi:10.3748/wjg.v19.i22.3439
PMCID: PMC3683682  PMID: 23801836
Endoscopy; Deep sedation; Anesthetic administration; Anesthetic dose; Adverse effects
18.  Comparison between Midazolam Used Alone and in Combination with Propofol for Sedation during Endoscopic Retrograde Cholangiopancreatography 
Clinical Endoscopy  2014;47(1):94-100.
Background/Aims
Endoscopic retrograde cholangiopancreatography (ERCP) is an uncomfortable procedure that requires adequate sedation for its successful conduction. We investigated the efficacy and safety of the combined use of intravenous midazolam and propofol for sedation during ERCP.
Methods
A retrospective review of patient records from a single tertiary care hospital was performed. Ninety-four patients undergoing ERCP received one of the two medication regimens, which was administered by a nurse under the supervision of a gastroenterologist. Patients in the midazolam (M) group (n=44) received only intravenous midazolam, which was titrated to achieve deep sedation. Patients in the midazolam pulse propofol (MP) group (n=50) initially received an intravenous combination of midazolam and propofol, and then propofol was titrated to achieve deep sedation.
Results
The time to the initial sedation was shorter in the MP group than in the M group (1.13 minutes vs. 1.84 minutes, respectively; p<0.001). The recovery time was faster in the MP group than in the M group (p=0.031). There were no significant differences between the two groups with respect to frequency of adverse events, pain experienced by the patient, patient discomfort, degree of amnesia, and gag reflex. Patient cooperation, rated by the endoscopist as excellent, was greater in the MP group than in the M group (p=0.046).
Conclusions
The combined use of intravenous midazolam and propofol for sedation during ERCP is more effective than midazolam alone. There is no difference in the safety of the procedure.
doi:10.5946/ce.2014.47.1.94
PMCID: PMC3928499  PMID: 24570889
Propofol; Midazolam; Cholangiopancreatography, endoscopic retrograde; Conscious sedation
19.  Patient-controlled sedation with propofol/remifentanil versus propofol/alfentanil for patients undergoing outpatient colonoscopy, a randomized, controlled double-blind study 
Saudi Journal of Anaesthesia  2014;8(Suppl 1):S36-S40.
Context:
Many techniques are used for sedation of colonoscopies. Patient-controlled sedation (PCS) is utilizing many drugs or drug combinations.
Aims:
The aim of this study is to compare the safety and feasibility of propofol/remifentanil versus propofol/alfentanil given to sedate patients undergoing outpatient colonoscopies through a patient-controlled technique.
Settings and Design:
Controlled randomized and double-blind study.
Materials and Methods:
A total of 80 patients were randomly divided into two groups; PA group received a combination of propofol/alfentanil and PR group received propofol/remifentanil combination. Patients were monitored for heart rate (HR), blood pressure (BP), oxygen saturation, and Ramsay sedation scale (RSS). Times of the following events were recorded; initiation of sedation, insertion and removal of the colonoscope, recovery and discharge. Five intervals were calculated; time to sedation, procedure time, postprocedure time, procedure room time, and postanesthesia care unit (PACU) time. Endoscopist and patient satisfaction scores were obtained.
Statistical Analysis Used:
Unpaired Student's t-test was used to compare between the two groups. Paired Student's t-test was used to compare baseline readings with readings after 30 min of sedation in the same group when needed.
Results:
Both groups showed slowing of the HR and decrease in mean arterial BP. HR and mean arterial BP were significantly lower 5 and 10 min after initiation of sedation in PR group when compared with PA group. Both HR and mean arterial BP returned to presedation readings 30 min after initiation of sedation in PR group but not in PA group. No differences between the two groups concerning oxygen saturation, RSS, endoscopist and patient satisfaction scores. Postprocedure and PACU times were significantly prolonged in PA group.
Conclusion:
PCS with either remifentanil/propofol or alfentanil/propofol for patients undergoing outpatient colonoscopy is safe and feasible. Remifentanil/proofol has more beneficial advantages in this setting secondary to its more rapid clearance.
doi:10.4103/1658-354X.144068
PMCID: PMC4268525  PMID: 25538518
Alfentanil; colonoscopy; patient-controlled sedation; remifentanil
20.  Post-sedation Events in Children Sedated for Dental Care 
Anesthesia Progress  2013;60(2):54-59.
Moderate oral sedation is used in pediatric dentistry for safe delivery of dental care to children. However, there is a paucity of data on the effects of pediatric dental sedations after discharge of children from the dental office. The purpose of this study was to evaluate and compare the incidence of adverse events occurring with meperidine and hydroxyzine versus midazolam alone 8 and 24 hours after sedation in pediatric dental patients. In this prospective study, a convenience sample of 46 healthy children presenting to a private pediatric dental practice for dental treatment needs was selected. A telephone survey of the parents of children sedated with either meperidine and hydroxyzine or midazolam alone was conducted 8 and 24 hours after the administration of sedation medications. Data analysis included descriptive statistics, frequency and proportion analysis, and Fisher exact test. Forty children were sedated with meperidine and hydroxyzine, and 6 who were sedated with midazolam. In both groups, 50% of the children slept in the car on the way home. Three children in the meperidine and hydroxyzine group vomited in the car. A significantly larger proportion of children in the meperidine and hydroxyzine group experienced prolonged sleep at home (P = .015). More children in the midazolam group exhibited irritability in the first 8 hours (P = .07). There were no statistical differences between the 2 groups with respect to incidence of pain, fever, vomiting, sleeping in the car, snoring, and difficulty in waking up. The lingering effects of orally administered sedation medications can lead to prolonged sleep, irritability, and vomiting in children after they have been discharged from the dental clinic. Most of these events occurred within the first 8 hours, but in some children the effects were seen up to 24 hours later.
doi:10.2344/0003-3006-60.2.54
PMCID: PMC3683881  PMID: 23763560
Sedation; Children; Adverse events
21.  Bispectral index monitoring as an adjunct to nurse-administered combined sedation during endoscopic retrograde cholangiopancreatography 
AIM: To determine whether bispectral index (BIS) monitoring is useful for propofol administration for deep sedation during endoscopic retrograde cholangiopancreatography (ERCP).
METHODS: Fifty-nine consecutive patients with a variety of reasons for ERCP who underwent the procedure at least twice between 1 July 2010 and 30 November 2010. This was a randomized cross-over study, in which each patient underwent ERCP twice, once with BIS monitoring and once with control monitoring. Whether BIS monitoring was done during the first or second ERCP procedure was random. Patients were intermittently administered a mixed regimen including midazolam, pethidine, and propofol by trained nurses. The nurse used a routine practice to monitor sedation using the Modified Observer’s Assessment of Alertness/Sedation (MOAA/S) scale or the BIS monitoring. The total amount of midazolam and propofol used and serious side effects were compared between the BIS and control groups.
RESULTS: The mean total propofol dose administered was 53.1 ± 32.2 mg in the BIS group and 54.9 ± 30.8 mg in the control group (P = 0.673). The individual propofol dose received per minute during the ERCP procedure was 2.90 ± 1.83 mg/min in the BIS group and 3.44 ± 2.04 mg in the control group (P = 0.103). The median value of the MOAA/S score during the maintenance phase of sedation was comparable for the two groups. The mean BIS values throughout the procedure (from insertion to removal of the endoscope) were 76.5 ± 8.7 for all 59 patients in using the BIS monitor. No significant differences in the frequency of < 80% oxygen saturation, hypotension (< 80 mmHg), or bradycardia (< 50 beats/min) were observed between the two study groups. Four cases of poor cooperation occurred, in which the procedure should be stopped to add the propofol dose. After adding the propofol, the procedure could be conducted successfully (one case in the BIS group, three cases in the control group). The endoscopist rated patient sedation as excellent for all patients in both groups. All patients in both groups rated their level of satisfaction as high (no discomfort). During the post-procedural follow-up in the recovery area, no cases of clinically significant hypoxic episodes were recorded in either group. No other postoperative side effects related to sedation were observed in either group.
CONCLUSION: BIS monitoring trend to slighlty reduce the mean propofol dose. Nurse-administered propofol sedation under the supervision of a gastroenterologist may be considered an alternative under anesthesiologist.
doi:10.3748/wjg.v18.i43.6284
PMCID: PMC3501778  PMID: 23180950
Conscious sedation; Bispectral index monitors; Pancreatic neoplasm; Endoscopic retrograde cholangiopancreatography
22.  Conscious Sedation and Emergency Department Length of Stay: A Comparison of Propofol, Ketamine, and Fentanyl/Versed 
Study Objectives:
Three of the most commonly used agents for conscious sedation in the Emergency Department (ED) are ketamine, fentanyl/versed, and propofol. In this study, we measured and compared the total times spent in the ED with each of these agents. Our objective was to determine whether the use of propofol for conscious sedation was associated with a shorter length of ED stay as compared to the other two agents.
Methods:
This was a consecutive case series. All patients who required procedural conscious sedation who presented to the ED at University of California, Irvine Medical Center from January 2003 through April 2004 were included in the study. The attending ED physician evaluated the patient and determined which medication(s) would be administered. All patients underwent procedural sedation according to the ED’s standardized sedation protocol. The times and dosages of administered medications and the sedation/consciousness level (SCL) scores were recorded by ED nurses at 3–5 minute intervals. Data was abstracted prospectively. The time to sedation (first dose of agent to SCL score of 2 or less) and time to recovery (last dose of agent to SCL score of 4) of the different regimens were then analyzed and compared.
Results:
Thirty-eight patients received propofol, 38 received ketamine, and 14 received fentanyl/versed. The mean times to sedation (minutes) were: propofol 4.5 (95% CI: 3.3–5.7), ketamine 10.6 (95% CI: 5.8–15.4), fentanyl/versed 11.5 (95% CI: 3.5–19.4). The mean times to recovery were: propofol 21.6 (95% CI: 16.1–27.1), ketamine 55.4 (95% CI: 46.2–64.5), fentanyl/versed 59.9 (95% CI: 20.3–99.5). Propofol had a statistically significant shorter time to sedation than both ketamine (p<.001) and fentanyl/versed (p=.022). Propofol also produced shorter recovery times than both ketamine (p<.001) and fentanyl/versed (p=.002).
Conclusion:
In this study, sedation and recovery times were shorter with propofol than with ketamine or fentanyl/versed. The use of propofol for conscious sedation in this non-randomized study was associated with a shorter ED length of stay.
PMCID: PMC2872520  PMID: 20505814
23.  Comparative evaluation of recovery characteristics of fentanyl and butorphanol when used as supplement to propofol anaesthesia 
Background and Aim:
Narcotics have been used since long as a component of balanced anaesthesia, thus minimizing the anaesthetic requirement both during induction and maintenance as well as attenuating the pressor response during laryngoscopy and intubation. Equally significant is their role in provision of smoother recovery period by minimizing postoperative pain. Other than pain, the factors like postoperative nausea and vomiting (PONV), shivering, sedation and respiratory depression are equally important in recovery from the effects of anaesthetic drugs. The present study aimed at comparing the postoperative recovery characterstics of fentanyl and butorphanol in patients undergoing open cholecystectomy under general anaesthesia.
Materials and Methods:
The present study configured one hundred adults patients of American Society of Anaesthesiologists (ASA) grade 1 or 2 of either sex scheduled to undergo elective open cholecystectomy and were randomly assigned to receive fentanyl (group F; n = 50) or butorphanol (group B; n = 50). Both group were premedicated with midazolam 0.04 mg/kg intravenously followed by injection fentanyl 2 mcg/kg or butorphanol 40 mcg/kg. Standard induction was done with propofol 2 mg/kg and vecuronium 0.1 mg/kg was used for intubation. Anaesthesia was maintained with propofol infusion and 67% nitrous oxide in oxygen. Intraoperative hemodynamic parameters were observed and recorded. Postoperatively analgesia, sedation, PONV, shivering, respiratory depression and recovery score were observed.
Results:
The recovery time was less in group F (P > 0.05) while post operative analgesia (P < 0.001) and sedation (P > 0.05) was more in group B. The incidence of respiratory depression was more in group B (P > 0.05). PONV was comparable in both the groups. Postoperative shivering was significantly low in group B (P < 0.05).
Conclusion:
It is concluded that besides easy availability and lower cost, butorphanol decreased propofol consumption intraoperatively and provided better analgesia and prophylaxis against shivering in postoperative period.
doi:10.4103/2229-516X.106350
PMCID: PMC3678702  PMID: 23776820
Butorphanol; fentanyl; propofol; recovery
24.  Midazolam and propofol used alone or sequentially for long-term sedation in critically ill, mechanically ventilated patients: a prospective, randomized study 
Critical Care  2014;18(3):R122.
Introduction
Midazolam and propofol used alone for long-term sedation are associated with adverse effects. Sequential use may reduce the adverse effects, and lead to faster recovery, earlier extubation and lower costs. This study evaluates the effects, safety, and cost of midazolam, propofol, and their sequential use for long-term sedation in critically ill mechanically ventilated patients.
Methods
A total of 135 patients who required mechanical ventilation for >3 days were randomly assigned to receive midazolam (group M), propofol (group P), or sequential use of both (group M-P). In group M-P, midazolam was switched to propofol until the patients passed the spontaneous breathing trial (SBT) safety screen. The primary endpoints included recovery time, extubation time and mechanical ventilation time. The secondary endpoints were pharmaceutical cost, total cost of ICU stay, and recollection to mechanical ventilation-related events.
Results
The incidence of agitation following cessation of sedation in group M-P was lower than group M (19.4% versus 48.7%, P = 0.01). The mean percentage of adequate sedation and duration of sedation were similar in the three groups. The recovery time, extubation time and mechanical ventilation time of group M were 58.0 (interquartile range (IQR), 39.0) hours, 45.0 (IQR, 24.5) hours, and 192.0 (IQR, 124.0) hours, respectively; these were significantly longer than the other groups, while they were similar between the other two groups. In the treatment-received analysis, ICU duration was longer in group M than group M-P (P = 0.016). Using an intention-to-treat analysis and a treatment-received analysis, respectively, the pharmaceutical cost of group M-P was lower than group P (P <0.01) and its ICU cost was lower than group M (P <0.01; P = 0.015). The proportion of group M-P with unbearable memory of the uncomfortable events was lower than in group M (11.7% versus 25.0%, P <0.01), while the proportion with no memory was similar (P >0.05). The incidence of hypotension in group M-P was lower than group (P = 0.01).
Conclusion
Sequential use of midazolam and propofol was a safe and effective sedation protocol, with higher clinical effectiveness and better cost-benefit ratio than midazolam or propofol used alone, for long-term sedation of critically ill mechanically ventilated patients.
Trial registration
Current Controlled Trials ISRCTN01173443. Registered 25 February 2014.
doi:10.1186/cc13922
PMCID: PMC4095601  PMID: 24935517
25.  Respiratory effects of dexmedetomidine in the surgical patient requiring intensive care 
Critical Care  2000;4(5):302-308.
The respiratory effects of dexmedetomidine were retrospectively examined in 33 postsurgical patients involved in a randomised, placebo-controlled trial after extubation in the intensive care unit (ICU). Morphine requirements were reduced by over 50% in patients receiving dexmedetomidine. There were no differences in respiratory rates, oxygen saturations, arterial pH and arterial partial carbon dioxide tension (PaCO2) between the groups. Interestingly the arterial partial oxygen tension (PaO2) : fractional inspired oxygen (FIO2) ratios were statistically significantly higher in the dexmedetomidine group. Dexmedetomidine provides important postsurgical analgesia and appears to have no clinically important adverse effects on respiration in the surgical patient who requires intensive care.
Introduction:
The α2-agonist dexmedetomidine is a new class of sedative drug that is being investigated for use in ICU settings. It is an effective agent for the management of sedation and analgesia after cardiac, general, orthopaedic, head and neck, oncological and vascular surgery in the ICU [1]. Cardiovascular stability was demonstrated, with significant reductions in rate-pressure product during sedation and over the extubation period.
Dexmedetomidine possesses several properties that may additionally benefit those critically ill patients who require sedation. In spontaneously breathing volunteers, intravenous dexmedetomidine caused marked sedation with only mild reductions in resting ventilation at higher doses [2]. Dexmedetomidine reduces the haemodynamic response to intubation and extubation [3,4,5] and attenuates the stress response to surgery [6], as a result of the α2-mediated reduction in sympathetic tone. Therefore, it should be possible to continue sedation with dexmedetomidine over the stressful extubation period without concerns over respiratory depression, while ensuring that haemodynamic stability is preserved.
The present study is a retrospective analysis of the respiratory response to dexmedetomidine in 33 postsurgical patients (who were involved in a randomized, double-blind, placebo-controlled trial [1]) after extubation in the ICU.
Methods:
Patients who participated in the present study were admitted after surgery to our general or cardiothoracic ICUs, and were expected to receive at least 6 h of postsurgical sedation and artificial ventilation.
On arrival in the ICU after surgery, patients were randomized to receive either dexmedetomidine or placebo (normal saline) with rescue sedation and analgesia being provided, only if clinically needed, with midazolam and morphine boluses, respectively. Sedation was titrated to maintain a Ramsay Sedation Score [7] of 3 or greater while the patients were intubated, and infusions of study drug were continued for a maximum of 6 h after extubation to achieve a Ramsay Sedation Score of 2 or greater.
The patients were intubated and ventilated with oxygen-enriched air to attain acceptable arterial blood gases, and extubation occurred when clinically indicated. All patients received supplemental oxygen after extubation, which was delivered by a fixed performance device. Assessment of pain was by direct communication with the patient.
Results are expressed as mean ± standard deviation unless otherwise stated. Patient characteristics, operative details and morphine usage were analyzed using the Mann-Whitney U-test. Statistical differences for respiratory measurements between the two groups were determined using analysis of variance for repeated measures, with the Bonferroni test for post hoc comparisons.
Results:
Of the 40 patients who participated in the study, seven patients could not be included in the analysis of respiratory function because they did not receive a study drug infusion after extubation. Consequently, data from 33 patients are used in the analysis of respiratory function; 16 received dexmedetomidine and 17 placebo. Inadequate arterial blood gas analysis was available in five patients (two from the dexmedetomidine group, and three from the placebo group). There were no significant differences in patient characteristics and operative details between the groups.
Requirements for morphine were reduced by more than 50% in patients receiving dexmedetomidine when compared with placebo after extubation (0.003 ± 0.004 vs 0.008 ± 0.006 mg/kg per h; P= 0.040).
There were no statistically significant differences between placebo and dexmedetomidine for oxygen saturations measured by pulse oximetry (P= 0.26), respiratory rate (P= 0.16; Fig. 1), arterial pH (P= 0.77) and PaCO2 (P= 0.75; Fig. 2) for the 6 h after extubation.
The dexmedetomidine group showed significantly higher PaO2: FIO2 ratios throughout the 6-h intubation (P= 0.036) and extubation (P= 0.037) periods (Fig. 3). There were no adverse respiratory events seen in either the dexmedetomidine or placebo group.
Respiratory rate for the 6-h periods before and after extubation. (Filled circle) Dexmedetomidine; (Empty circle) placebo. Values are expressed as mean ± standard deviation.
PaCO2 (PCO2) for the 6-h periods before and after extubation, and baseline values (B) on admission to ICU immediately after surgery. (Filled circle) Dexmedetomidine; (Empty circle) placebo. Values are expressed as mean ± standard deviation.
PaO2 : FIO2 ratio for the 6-h periods before and after extubation, and baseline values (B) on admission to ICU immediately after surgery. (Filled circle) Dexmedetomidine; (Empty circle) placebo. Values are expressed as mean ± standard deviation.
Discussion:
Lack of respiratory depression in patients sedated with α2-adrenoceptor agonists was first reported by Maxwell [8] in a study investigating the respiratory effects of clonidine. However, more recent data suggests that clonidine may cause mild respiratory depression in humans [9], and α2-adrenoceptor agonists are well known to produce profound intraoperative hypoxaemia in sheep [10,11]. The effects of dexmedetomidine on other ventilation parameters also appear to be species specific [12].
Belleville et al [2] investigated the ventilatory effects of a 2-min intravenous infusion of dexmedetomidine on human volunteers. According to those investigators, minute ventilation and arterial PaCO2 were mildly decreased and increased, respectively. There was a rightward shift and depression of the hypercapnic response with infusions of 1.0 and 2.0 μg/kg.
Previous studies that investigated the respiratory effects of dexmedetomidine have only been performed in healthy human volunteers, who have received either single intramuscular injections or short (= 10 min) intravenous infusions of dexmedetomidine. It is therefore reassuring that no deleterious clinical effects on respiration and gas exchange were seen in the patients we studied, who were receiving long-term infusions. However, there are important limitations to the present results. No dose/response curve for dexmedetomidine can be formulated from the data, and further investigation is probably ethically difficult to achieve in the spontaneously ventilating intensive care patient. We also have no data on the ventilatory responses to hypercapnia and hypoxia, which would also be difficult to examine practically and ethically. The placebo group received more than twice as much morphine as patients receiving dexmedetomidine infusions after extubation, but there were no differences in respiratory rate or PaCO2 between the groups. We can not therefore determine from this study whether dexmedetomidine has any benefits over morphine from a respiratory perspective.
There were no differences in oxygen saturations between the groups because the administered oxygen concentration was adjusted to maintain satisfactory gas exchange. Interestingly, however, there were statistically significant higher PaO2 : FIO2 ratios in the dexmedetomidine group. This ratio allows for the variation in administered oxygen to patients during the study period, and gives some clinical indication of alveolar gas exchange. However, this variable was not a primary outcome variable for the present study, and may represent a type 1 error, although post hoc analysis reveals that the data have 80% power to detect a significant difference (α value 0.05). Further studies are obviously required.
Sedation continued over the extubation period, has been shown to reduce haemodynamic disturbances and myocardial ischaemia [13]. We have previously shown [1] that dexmedetomidine provides cardiovascular stability, with a reduction in rate-pressure product over the extubation period. A sedative agent that has analgesic properties, minimal effects on respiration and offers ischaemia protection would have enormous potential in the ICU. Dexmedetomidine may fulfill all of these roles, but at present we can only conclude that dexmedetomidine has no deleterious clinical effects on respiration when used in doses that are sufficient to provide adequate sedation and effective analgesia in the surgical population requiring intensive care.
PMCID: PMC29047  PMID: 11056756
α2-Adrenoceptor agonist; analgesia; dexmedetomidine; intensive care; postoperative; respiratory; sedation

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