Multiple studies have shown that cerebral tissue oxygen saturation () is decreased after phenylephrine treatment. We hypothesized that the negative impact of phenylephrine administration on is affected by arterial blood carbon dioxide partial pressure () because CO2 is a powerful modulator of cerebrovascular tone.
In 14 anaesthetized healthy patients, i.v. phenylephrine bolus was administered to increase the mean arterial pressure ∼20–30% during hypocapnia, normocapnia, and hypercapnia. and cerebral blood volume (CBV) were measured using frequency domain near-infrared spectroscopy, a quantitative technology. Data collection occurred before and after each treatment.
Phenylephrine caused a significant decrease in during hypocapnia [=−3.4 (1.5)%, P<0.001], normocapnia [=−2.4 (1.5)%, P<0.001], and hypercapnia [=−1.4 (1.5)%, P<0.01]. Decreases in were significantly different between hypocapnia, normocapnia, and hypercapnia (P<0.001). Phenylephrine also caused a significant decrease in CBV during hypocapnia (P<0.01), but not during normocapnia or hypercapnia.
The negative impact of phenylephrine treatment on and CBV is intensified during hypocapnia while blunted during hypercapnia.
carbon dioxide; cerebral blood volume; cerebral tissue oxygen saturation; modulation; phenylephrine
Intraoperative arterial hypotension can lead to severe complications in patients undergoing carotid endarterectomy, in particular if cerebral auto-regulation is impaired. Short-acting agents, such as phenylephrine or ephedrine, commonly used to correct intra-operative hypotension, have different hemodynamic effects. Recently, it was reported that, in healthy anesthetized subjects with intact cerebral auto-regulation, frontal lobe cerebral tissue oxygenation declined after phenylephrine bolus administration, while it was preserved after ephedrine use (Br J Anaesth 107:209–217, 2011; Neurocrit Care 12:17–23, 2010). However, the effect of both agents in patients undergoing carotid endarterectomy is unknown. The aim of this study is to assess the effect of two routinely used vasopressors (phenylephrine and ephedrine) on the cerebral hemodynamics during carotid endarterectomy.
Patients undergoing carotid endarterectomy will be prospectively included and randomized for correction of intraoperative hypotension with either phenylephrine (50 to 100 μg) or ephedrine (5 to 10 mg). If hypotension persists for more than five minutes after treatment, the patient will be classified as a non-responder and escape medication as preferred by the anesthesiologist will be administered. Changes in cerebral hemodynamics will be quantified by changes in transcranial Doppler-derived middle cerebral artery blood velocity and near infra-red spectroscopy-derived frontal lobe cerebral tissue oxygenation, when intra-operative hypotension is treated with phenylephrine or ephedrine in patients who undergo carotid endarterectomy with or without an adequate functioning cerebral auto-regulation.
To quantify whether the intra-operative cerebral auto-regulation is impaired or not, a decrease in breathing frequency from the normal 12 breaths per minute to 6 breaths per minute for an episode of three minutes will be performed.
Phenylephrine and ephedrine are two of the most commonly used short-acting agents to increase blood pressure in clinical anesthesiologic practice. Monitoring of middle cerebral artery blood velocity with transcranial Doppler and frontal lobe cerebral tissue oxygenation with near infra-red spectroscopy are part of the standard of care. Furthermore, there are no reports that the three-minute modification in breathing frequency described in the “intervention”-section is harmful. Therefore, the risks for participating patients are negligible and the burden minimal.
Clinical trials.gov: NCT01451294
Carotid endarterectomy; Cerebral oxygenation; Intraoperative hypotension; Phenylephrine; Ephedrine
Several studies have demonstrated that ephedrine shortens the onset time of muscle relaxants, and it does so probably by increasing the cardiac output. However, elevation of the systemic blood pressure through α adrenergic stimulation via ephedrine may affect the onset of muscle relaxants during the induction of anesthesia. We investigated the effect of phenylephrine, which is a selective α-1 agonist, on the onset time of rocuronium and the intubating conditions in adults after the administration of propofol.
Sixty-four patients were randomly assigned to two groups. Phenylephrine (0.9 µg/kg) (P group) or the same volume of saline (S group) was injected before rocuronium (0.6 mg/kg) administration. Anesthesia was induced with fentanyl 2 µg/kg and propofol 2 mg/kg. The onset time was defined as the time from the end of rocuronium injection to the time when a single twitch height gets to 0% or the minimum level. A well-trained anesthesiologist who was 'blinded' to the treatment groups evaluated the intubating conditions. The mean arterial pressure and heart rate were recorded before induction, before intubation, immediately after intubation and 1 minute and 2 minutes after intubation.
The onset time was 84 ± 18 sec in the P-group and 72 ± 14 sec in the S-group. There was no difference of the intubating conditions, the mean arterial pressure and the heart rate between the two groups.
A small dose of phenylephrine, which has a limited effect on blood pressure, delayed the onset time of rocuronium after the administration of propofol, and the vasoconstriction effect of phenylephrine may affect the prolongation of the rocuronium onset time at the induction of anesthesia with using propofol.
Onset time; Phenylephrine; Rocuronium
This randomized double blind study was started with an objective of management of spinal anaesthesia-induced hypotension in elective caesarean section by combining two commonly used vasopressors – ephedrine and phenylephrine in half of their usual doses with an expectation of reducing their foetomaternal side effects.
One hundred and thirty two patients were randomized into three groups to receive either 100 μg/ml phenylephrine (group-P, n=31) or 3 μg/ml ephedrine (group-E, n=33) or 50 mg phenylephrine plus 1.5 mg ephedrine/ml (group-PE, n=29). Immediately after spinal injection the study solution was started prophylactically in every patient at the rate of 40 ml/h. A predefined algorithm was used to adjust the infusion rate according to the systolic blood pressure (SBP).
Mean fall of SBP was significantly more in group-E than group-P (P=0.009) and group-PE (P=0.013). This was not significantly different when compared between group-P and group-PE (P=0.9). Episodes of hypotension and tachycardia were more in group-E than the other two groups. Statistically significant tachycardia was seen in Group-E than that in other two groups. Incidence of bradycardia and hypertension did not differ significantly among the groups. Maternal nausea and Apgar score were also comparable in three groups.
Current study claims that prophylactic phenylephrine 100 mg/ml is a better choice than ephedrine (3 mg/ml) or 50 mcg phenylephrine plus 1.5 mg ephedrine/ml in prevention of spinal anaesthesia-induced hypotension in elective caesarean section. Combination of two drugs in half the usual dose has no added advantage over phenylephrine, but this is better than ephedrine alone.
Bradycardia; elective caesarean section; hypotension; spinal anaesthesia; vasopressors
A fixed dose of propofol administered rapidly can be insufficient or in excess resulting in airway complications and haemodynamic disturbances. This study is designed to assess whether loss of motor response to jaw thrust can be a reliable clinical indicator of anaesthetic depth for laryngeal mask airway (LMA) insertion.
One hundred and twenty ASA I and II patients scheduled for general anaesthesia on day care basis were randomly allocated into two groups. Following pre-oxygenation, anaesthesia was induced to accomplish LMA insertion either with a 3 mg/kg propofol (Group CD, n=60) or in dose to abolish jaw thrust response (Group JT, n=60). Mean arterial pressure (MAP) and heart rate were continuously monitored while LMA insertion conditions were recorded using 6 variable, 3 point score.
85% patients developed apnea in group CD when compared to 2% in group JT, P<0.0001. Despite similar insertion score, propofol consumption was significantly more in group CD when compared to group JT. More than 20% fall of MAP from baseline was noted in group CD after induction but there was no significant hypotension at any time in group JT.
Loss of motor response to jaw thrust provides satisfactory LMA insertion conditions.
Anaesthesia; general drugs; propofol equipment; laryngeal mask airway
Modified electroconvulsive therapy (ECT) is a safe and most effective treatment modality for major depressive disorders with suicidal tendencies. For this, one must have an ideal intravenous anaesthetic agent for induction which provides rapid onset, short duration of action, attenuates adverse physiological effect of ECT, rapid recovery without adverse shortening of seizure duration and minimum rise in serum potassium. The studies in search of an ideal intravenous anaesthetic agent are limited. Aim is to compare the effect of iv thiopentone, propofol and midazolam on induction time and quality, haemodynamics, Seizure duration, recovery time and changes in serum potassium level. 90 patients of ASA I and II of either sex having major depressive illness were randomly allocated into three groups (n = 30) based on iv induction agent used. Group I, Group II and Group III patients were induced with iv thiopentone 5 mg/kg, propofol 2 mg/kg and midazolam 0.2 mg/kg, respectively. The induction time, quality of induction, haemodynamic changes, seizure duration, recovery time and change in serum potassium level were measured and analyzed by Z test. Induction was quicker in propofol group i.e., 41.03 ± 6.11 sec than in thiopentone (50.6 ± 6.32 sec) and midazolam group (77.30 ± 6.67 sec). Seizure duration was significantly shorter in midazolam group compared to propofol and thiopentone groups. Though significant rise in HR, SBP DBP was observed in all the three groups following ECT, but rise was significantly higher in thiopentone group compared to other two groups. Significantly, faster recovery was observed with propofol. Rise in serum potassium after ECT was not significant in any of the groups. Propofol is a safe and suitable intravenous anaesthetic agent for induction of anaesthesia for modified ECT.
Midazolam; modified electroconvulsive therapy; propofol; thiopentone
Maintaining systolic blood pressure (SBP) at 100% of baseline is best for fetal and maternal outcome. We hypothesized that irrespective of the vasopressor used, maintaining SBP at 100% of baseline with phenylephrine (P), metaraminol (M), or ephedrine (E) will produce the best fetal pH after cesarean section (LSCS) under subarachnoid block (SAB).
Materials and Methods:
Ninety ASA 1 women scheduled for elective LSCS were randomly allocated to receive P, M, or E. SAB was established with patient in left lateral position using 2.5 cc of 0.5% hyperbaric bupivacaine. Immediately following SAB, patients received a bolus of the study drug (E = 5 mg, M = 0.5 mg, P = 30 mcg) followed by infusion (E = 2.5 mg/min, M = 0.25 mg/min, P = 15 mcg/min) to maintain SBP at 100% baseline. Umbilical blood gases, maternal hemodynamic parameters, and complications were recorded.
The umbilical pH was comparable in all the three groups (P > 0.05). The mean SBP from spinal block until delivery was similar over time for all the three groups. The incidence of reactive hypertension was more in group M (P < 0.05) than in group E and group P. Total drug consumption to meet target blood pressure till delivery was 39.3 ± 14.6 mg in group E, 1.7 ± 0.9 mg in group M, and 283.6 ± 99.8 mcg in group P. The incidence of nausea and vomiting was comparable in the three groups.
All the three vasopressors were equally effective in maintaining maternal blood pressure as well as umbilical pH during spinal anesthesia for cesarean section without any detrimental effects on fetal and maternal outcome.
Cesarean section; fetal pH; spinal anaesthesia; vasopressors
This randomised, placebo-controlled, double-blind study was designed to assess the effect of intravenous clonidine and magnesium sulphate on intraoperative haemodynamics, anaesthetic consumption and postoperative recovery. Seventy five patients undergoing elective upper limb orthopaedic surgery were randomised into three groups. Group C received clonidine 3 μg/kg as a bolus before induction and 1μg/kg/hour by infusion intraopertively. Group M received magnesium sulphate 30 mg/kg as a bolus before induction and 10 mg/kg/hour by infusion. Group P received same volume of isotonic saline. Anaesthesia was induced and maintained with fentanyl citrate and propofol. Muscular relaxation was achieved by vecuronium bromide. Induction time, recovery time and consumption of propofol as well as fentanyl citrate were recorded. Induction of anaesthesia was rapid with both clonidine and magnesium sulphate. Time of bispectral index (BIS) to reach 60 was significantly lower in Group C and Group M (P < 0.0001). Requirements of propofol and fentanyl were significantly less in Group C and Group M (P < 0.001). Postoperative recovery was slower in Group M compared with other two groups (P < 0.001). Perioperative use of both clonidine and magnesium sulphate significantly reduced the consumption of propofol and fentanyl citrate. Magnesium sulphate caused a delayed recovery.
Anaesthetic consumption; bispectral index; clonidine; magnesium sulphate
Previous work demonstrated that maternal haplotypes of the β2-adrenoceptor gene (ADRB2) influence ephedrine requirements during cesarean delivery. The use of ephedrine versus a pure α-adrenergic agonist such as phenylephrine has been associated with lower umbilical artery (UA) pH, thought to be secondary to increased fetal metabolism. There are no data evaluating the effect of fetal/neonatal genotypes on the metabolic response to maternally administered vasopressors. We hypothesized that neonatal ADRB2 genotype would affect the extent of neonatal acidemia. We also examined the effect of maternal ADRB2 and the endothelial nitric oxide synthase gene (NOS3) on ephedrine and phenylephrine requirements for treatment of maternal hypotension.
The study was performed on 104 Chinese women scheduled for cesarean delivery under spinal anesthesia who were participating in a double-blinded randomized clinical trial evaluating the maternal and neonatal effects of ephedrine versus phenylephrine infusions. Blood samples were drawn from the UA, umbilical vein and maternal radial artery to measure blood gas values, lactate, ephedrine and phenylephrine concentrations, and determine maternal and neonatal genotype at non-synonymous single nucleotide polymorphisms at codons 16 (rs1042713) and 27 (rs1042714) of ADRB2 and codon 298 (rs1799983) of NOS. Clinical variables (UA pH, UA lactate and dose of vasopressors) among genotypes were compared, and regression models were created to assess the effect of genotype on vasopressor dose and fetal acid-base status.
Maternal ADRB2 genotype did not affect the ephedrine dose. Neonatal genotype at codon 16 influenced fetal acid-base status. UA pH was higher in Arg16 homozygous neonates (7.31 ± 0.03 in p.16Arg/Arg vs 7.25 ± 0.11 in p.16 Arg/Gly and p.16 Gly/Gly; p < 0.001, 95% C.I of difference 0.03 ~ 0.09) and UA lactate was lower (2.67 mmol/L ± 0.99 in p.16Arg/Arg vs 4.28 mmol/L ± 2.79 in p.16 Arg/Gly and p.16 Gly/Gly; p < 0.001, 95% C.I of difference −2.40 ~ −0.82). In neonates born to mothers receiving ephedrine, the magnitude of the difference among genotypes was even greater (pH 7.30 ± 0.02 in p.16Arg/Arg vs 7.19 ± 0.10 in p.16 Arg/Gly and p.16 Gly/Gly; p < 0.001, 95% C.I of difference 0.07 ~ 0.14) and UA lactate was lower (3.66 mmol/L ± 1.30 in p.16Arg/Arg vs 5.79 mmol/L ± 2.88 in p.16 Arg/Gly and p.16 Gly/Gly; p = 0.003, 95% C.I of difference −3.48 ~ −0.80). In a multiple linear regression model (R2 = 63.6%; P = 0.03), neonatal ADRB2 genotypes (p.16Arg/Arg and p.27Gln/Glu) and lower neonatal birth weight predicted lower UA lactate concentrations.
Phenylephrine dose was not affected by maternal ADRB2 or NOS3 genotypes, and neonatal NOS3 genotype did not affect UA pH or UA lactate.
In contrast to previous findings in a North American cohort, maternal ADRB2 genotype did not affect ephedrine requirements during elective cesarean delivery in a Chinese cohort. However, our findings suggest that neonatal ADRB2 p.Arg16 homozygosity confers a protective effect against developing ephedrine-induced fetal acidemia.
Accepted 14 August 1996
Midazolam is the sedating agent of choice in many paediatric
intensive care units, and is usually administered as a continuous intravenous infusion with or without a preceding bolus dose.
Ten haemodynamically stable children, ventilated in the early
postoperative period after cardiac surgery and receiving intravenous morphine infusions, were given an intravenous bolus followed by a
continuous infusion of midazolam. Haemodynamic data were recorded before the bolus, and 15 minutes and one hour later. A bolus of midazolam lowered the cardiac output by 24.1%. Arterial blood pressure, oxygen consumption, and mixed venous oxygen content fell
significantly. There was a tendency for all variables subsequently to
recover towards baseline values, within one hour, during a continuous infusion.
An intravenous bolus of midazolam causes a transient but unwanted
fall in cardiac output. It is suggested that in children who are
receiving intravenous opiates, its use in the early postoperative period be limited to a continuous infusion.
The benefit of prophylactic combination therapy using crystalloid and colloid preload with ephedrine has not been cleared to prevent maternal hypotension after spinal anesthesia at cesarean delivery. This study evaluated the efficacy of three combinational methods to prevent hypotension following spinal anesthesia.
Materials and Methods:
In this prospective double blind trial, 150 candidates of elective cesarean delivery under spinal anesthesia were randomly allocated to three treatment groups; 1---Ringer's Lactate (RL) solution (15 ml/kg) plus Hemaxel (7 ml/kg) preload, 2---RL solution (15 ml/kg) preload plus ephedrine (15 mg, IV, bolus), 3---Hemaxel (7 ml/kg) preload plus ephedrine (15 mg, IV, bolus). Maternal hemodynamic changes during 60 min after spinal injection, nausea/vomiting, and neonatal condition were compared among the groups.
The cumulative incidence of hypotension was 44%, 40%, and 46% in groups 1 to 3, respectively. There were not significant differences in supplementary ephedrine requirement among groups which received or among groups which did not receive prophylactic ephedrine. Groups were not different in the incidence of hypertension and nausea or vomiting. There were no significant differences among groups in Apgar scores at 1 or 5 min and umbilical artery PH.
Combination of preventive methods decreased the occurrence of hypotension following spinal anesthesia to an acceptable level. Overall, the most effective method was a combination of crystalloid preload with ephedrine.
Cesarean delivery; hypotension; spinal anesthesia
Spinal anesthesia causes hypotension and bradycardia due to sympathetic nerve block and it is difficult to predict the level of sensory block and the duration of blockade. Recent studies have reported that intravenous phenylephrine can reduce the rostral spread of spinal anesthesia in pregnant women. We think a phenylephrine infusion will be useful for maintaining the baseline blood pressure by reducing the rostral spread of spinal anesthesia during the elective surgery of non-obstetric patients.
Sixty patients who were undergoing urologic surgery were randomized into two groups: Group C (the control group without phenylephrine) and Group P (with the addition of phenylephrine). After a bolus infusion of 50 µg phenylephrine following the spinal injection, phenylephrine was continuously infused at the rate of 200 µg/hr. We compared the dermatomal spreads of spinal anesthesia, the hemodynamic parameters (blood pressure, heart rate) and the incidences of hypotension between the two groups.
At 20 minutes, the level of the upper dermatome blocked against cold sensation was a median of T8 (interquartile range: T8-T10) for the phenylephrine group, as compared with T4 (interquartile range: T4-T6) for the control group (P < 0.001).
Intravenous phenylephrine can decrease the rostral spread of spinal anesthesia during urologic surgery.
Cerebrospinal fluid; Dermatomal spread; Phenylephrine; Sensory block; Spinal anesthesia
Multiple sclerosis (MS) is a rare autoimmune demyelinating disorder of the central nervous system clinically manifesting as periodic attacks of varied neurologic symptoms, eventually progressing to fixed neurologic deficits and disability. The treatment is symptomatic and directed towards prevention of future progression of the disease involving multiple agents. We present here a case report of a patient with MS who underwent an orthopaedic procedure under general anaesthesia (G.A.) uneventfully. Anaesthetic implications include assessment of neurological deficits with documentation pre- and postoperatively, awareness towards side-effects, potential drug interactions of medications, selection of suitable techniques/anaesthetic agents, neuromuscular monitoring-guided titration of non-depolarizing blocking agents with lowest necessary dose and avoidance of hyperthermia along with temperature, haemodynamic and respiratory monitoring. Lower concentrations of local anaesthetic (LA) should be used for regional blocks keeping in mind the susceptibility of demyelinated neurons, towards LA neurotoxicity. To the best of our knowledge, this is the first report of anaesthetic management of MS in India.
Anaesthetic; demyelination; multiple sclerosis
Hypotensive episodes are a common complication of spinal anesthesia during Cesarean section. The purpose of this study was to compare the effectiveness and the side effects of vasopressors, ephedrine and phenylephrine, administered for hypotension during elective Cesarean section under spinal anesthesia.
Material and methods
The study consisted of 100 selected ASA I/II females scheduled for elective Cesarean section under spinal anesthesia. Each patient was randomly assigned to one of the two double-blind study groups. Group E received 1 ml ephedrine (5 mg/ml) with normal saline if hypotension was present (n=50). Group P received 1 ml phenylephrine (100 µg/ml) with normal saline if hypotension developed (n=50). Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) were compared within and between groups to basal levels at time increments of 0, 2, 4, 6, 8, 10, 15, 20, 25, 30, 45, and 60 min from start of surgery. Incidence of side effects and neonatal outcomes were studied between groups.
All patients required vasopressor therapy for hypotension. Administration of phenylephrine was associated with significant drop in HR. Changes in SBP, DBP, and MAP were similar in both groups for most observed times. The incidences of nausea/vomiting and tachycardia were significantly higher in the ephedrine group.
Phenylephrine and ephedrine are acceptable choices to combat maternal hypotension related to spinal anesthesia in elective Cesarean section. Complications of intra-operative nausea and vomiting, tachycardia and bradycardia should be considered when choosing a vasopressor, suggesting phenylephrine may be more appropriate when considering maternal well-being.
ephedrine; phenylephrine; spinal anesthesia; Cesarean section
AIM—To assess the safety and efficacy of EMLA
cream (eutectic mixture of local anaesthetics) used to induce surface
anaesthesia for venepuncture in healthy preterm infants.
METHODS—Nineteen infants, median gestational age
31 weeks (range 26-33 weeks) were assessed in a randomised, double
blind, placebo controlled, cross-over trial. Changes in physiological
variables (heart rate, blood pressure, oxygen saturation) and
behavioural responses (neonatal facial coding system score, crying
time) before and after venepuncture with EMLA cream were compared with
those obtained with a placebo cream to assess efficacy. Toxicity was assessed by comparing methaemoglobin concentrations at 1 hour and 8 hours after application.
RESULTS—There was no significant difference in
efficacy between EMLA and placebo creams in physiological and
behavioural responses. There was no significant difference in
methaemoglobin concentrations one hour after the cream had been
applied. At eight hours, however, concentrations were significantly
higher after EMLA than placebo (p=0.016). There was no evidence of
CONCLUSION—This study does not support the routine
use of EMLA for venepuncture in healthy preterm infants.
Ma Huang (equivalent to 0, 12.5, 25, or 50 mg/kg ephedrine) or ephedrine (0, 6.25, 12.5, 25 mg/kg) were administered as one bolus oral dose to male F344 rats with and without caffeine. The herbal medicine Ma Huang (ephedra) in combination with caffeine caused rapid clinical signs of toxicity including salivation, hyperactivity, ataxia, and eventually lethargy, and failure to respond to stimuli. When this syndrome of clinical signs emerged, animals were moribund sacrificed, and a histological analysis for heart lesions performed. Cardiotoxicity included hemorrhage, necrosis, and degeneration in the ventricles or interventricular septum within 2–4 hours after treatment with Ma Huang (ephedra)/caffeine or ephedrine (the principal active component in Ma Huang)/caffeine. There was a steep dose response curve for cardiotoxicity with minimal toxicity seen at levels of Ma Huang (equivalent to 12.5 mg/kg ephedrine) with caffeine. However, cardiotoxic lesions occurred in 28% of animals with Ma Huang dosages equivalent to 25 mg/kg ephedrine with 15 or 30 mg/kg caffeine, and in 90% of animals at Ma Huang exposures equivalent to 50 mg/kg ephedrine with 15 or 30 mg/kg caffeine. Cardiotoxic lesions occurred in 47% of animals in the 25 mg/kg ephedrine groups with caffeine at 7.25, 15, or 30 mg/kg. There was no statistical difference in the occurrence of cardiotoxic lesions when 15 or 30 mg/kg caffeine was combined with Ma Huang equivalent to 25 or 50 mg/kg ephedrine; likewise there was no statistical difference in the occurrence of cardiotoxic lesions when 7.25, 15, or 30 mg/kg caffeine was combined with 25 mg/kg ephedrine. These results show that the cardiotoxic effects of the herbal medicine, Ma Huang, are similar to that of ephedrine, the principal active ingredient in the herbal medicine. The combination of Ma Huang or ephedrine with caffeine enhanced the cardiotoxicity over that with the herbal medicine or the active ingredient alone.
Cardiotoxicity; Ma Huang; ephedra; ephedrine; caffeine
Topical phenylephrine solutions are widely used in eye procedures to promote pupil dilation without cycloplegia. We report a case of intraoperative severe hypertension and acute pulmonary edema occurring in a child during retinal surgery after possible systemic absorption of topical phenylephrine eyedrops. Our objective is to discuss the proper treatment and preventive strategies for such a complication. A 4-year-old, male patient, 18.4 kg in weight, physical status ASA I was admitted for right retinal detachment surgery. Anesthesia was induced with sevoflurane in oxygen, followed by glycopyrrolate (5.0 μg/kg), propofol 25 mg, fentanyl 50 μg and cisatracurium 0.15 mg/kg given intravenously. Anesthesia was maintained with sevoflurane 2-2.5% in a mixture of nitrous oxide and oxygen (60%:40%). After incision, two drops of 10% aqueous phenylephrine were administered topically by the surgeon to the right eye for further pupil dilation. Few minutes later, the noninvasive blood pressure rose to 220/120 mmHg and the heart rate increased to 140 beats/min. Oxygen saturation (SpO2) dropped from 99% (with an inspired oxygen concentration (FiO2) of 0.4) to 82%. Auscultation revealed crepitations throughout the chest and a blood-stained frothy fluid was aspirated from the trachea with possible development of acute pulmonary edema. Hydralazine (5 mg) and furosemide (10 mg) were administered intravenously. Seven minutes later, the blood pressure returned to normal and the SpO2 increased to 92% on FiO2 of 1.0, with decreased intratracheal secretions. After approximately 20 minutes, the SpO2 had improved to 99%, with a FiO2 of 1.0 and the blood pressure was 109/63 mmHg and heart rate was 121 beats/min. The FiO2 gradually reduced back to 0.4 over 30 min with no further desaturation. The patient was discharged from the post anesthesia care unit 5 h after surgery with adequate spontaneous breathing, SpO2 99% on room air, normal blood pressure and pulmonary auscultation. Anesthesiologists and ophthalmologists should be aware of the possible cardiovascular side-effects of topical phenylephrine, and it should be used cautiously with appropriate intraoperative monitoring of hemodynamic variables. Moreover, preventive strategies to minimize systemic absorption of the drug should be taken.
Acute pulmonary edema; child; hypertension; phenylephrine; retinal; surgery
A double blind randomized prospective study was undertaken to determine the effect of adjuncts like epinephrine 200μg or clonidine 90μg in combination of bupivacaine and lignocaine into the brachial plexus sheath to study the sensory and motor onset, duration of analgesia, hemodynamic changes and adverse effects.
Patients & Methods:
60 patients aged 18-65 years, with ASA grade I and II were randomly divided into group I and group II to receive 10 ml of lignocaine2% and 20 ml of bupivacaine0.5% with 1ml of 200μg epinephrine or 90μg clonidine respectively. Onset of sensory blockade was determined by pinprick method by a three point score and motor blockade by three point scale. Duration of postoperative analgesia, the hemodynamic changes, sedation scores and any adverse effects were observed. Statistical analysis was done by student's “t” test and p<0.05 was considered significant.
It was found that there was faster onset of sensory and motor blockade, the postoperative analgesia was prolonged and the amount of sedation was profound in group II as compared to group I. All the above findings were statistically significant.
We thereby conclude that clonidine 90μg is a better option as an additive than epinephrine 200μg for hastening the onset of sensory and motor block with prolonged postoperative analgesia and sedation as the only adverse effect.
Supraclavicular brachial plexus block; Clonidine; Epinephrine
We aimed to investigate the effects on post-operative pain of local anaesthetic administration via a catheter placed into the operation site in patients who were undergoing upper and lower extremity paediatric orthopaedic surgery.
In this randomised, double-blind and placebo study, 40 ASA I–II patients aged between 1 and 12 years were randomly allocated into two groups: study group (Group S: 0.2 ml/kg, 0.5% bupivacaine, n = 20) and control group (Group C: 0.2 ml/kg, serum physiologic, n = 20). Before the fascia was closed by the surgical team, the solution previously prepared by the chief nurse was injected into the subfascial soft tissue with the syringe as the “injected dose” of serum physiologic or bupivacaine. After the closure, 0.2 ml/kg (1 mg/kg) bupivacaine or saline was instillated as the “first instillated dose” into the surgical area via the catheter. Pain scores were recorded at 0, 1, 2, 4, 8, 12, 24 and 48 h post-operatively. Patients were administered 0.75 mg/kg meperidine intramuscularly post-operatively to equalise the pain scores.
No statistically significant difference was found between Group S and Group C in terms of demographic and other data and pain scores in the post-anaesthesia care unit, while a statistically significant decrease was found at 2, 4, 8, 12, 24 and 48 h in Group S and at 1, 2 and 4 h in Group C based on pain scores in the post-anaesthesia care unit (P < 0.05). A statistically significant decreasing pain score was found at 4, 8, 12, 24 and 48 h in Group S (P < 0.05).
The local anaesthetic administered via a catheter implanted in the surgical field may provide long-term and efficient post-operative analgesia.
Post-operative pain; Paediatric; Local anaesthetic
We report the anaesthetic management of a 48-year-old male patient with Deafness, Onycho-Osteodystrophy and mental Retardation syndrome, epilepsy and cerebral palsy who had two dental procedures under anaesthetic care. For the first short examination sedoanalgesia was employed and the second, longer, procedure was performed under general anaesthesia. His airway management was moderately difficult and the postoperative period was complicated by partial seizures involving the upper extremity and a short period of decreased oxygen saturation. The potential anaesthetic implications of Deafness, Onycho-Osteodystrophy and mental Retardation syndrome are highlighted.
Prevention of intraoperative hypothermia has become a standard of operative care. Since ephedrine has a thermogenic effect and it is frequently used to treat hypotension during anesthesia, this study was designed to determine the effect of ephedrine on intraoperative hypothermia of patients who are undergoing spine surgery.
Twenty-four patients were randomly divided to receive an ephedrine (the ephedrine group, n = 12) or normal saline (the control group, n = 12) infusion for 2 h. The esophageal temperature (the core temperature), the index finger temperature (the peripheral temperature) and the hemodynamic variables such as the mean blood pressure and heart rate were measured every 15 minutes after the intubation.
At the end of the study period, the esophageal temperature and hemodynamic variables were significantly decreased in the control group, whereas those in the ephedrine group were stably maintained. The index finger temperature was significantly lower in the ephedrine group compared to that in the control group, suggesting the prevention of core-to-peripheral redistribution of the heat as the cause of temperature maintenance.
An intraoperative infusion of ephedrine minimized the decrease of the core temperature and it stably maintained the hemodynamic variables during spine surgery with the patient under general anesthesia.
Anesthesia; General; Hypothermia; Temperature
Hydroxyethyl starch (HES) solutions are synthetic non-protein colloid solutions used to treat hypovolemia. However, their use is not free from the risk of allergic reactions. A 42-year-old male was scheduled to undergo aortic-iliac-femoral bypass surgery for the treatment of arteriosclerosis obliterans. He had no history of allergy. Two hours after the start of surgery, and within minutes after HES administration, facial erythema, hypotension and bronchospasm developed. HES infusion was discontinued under the estimation of anaphylaxis. The patient received phenylephrine, ephedrine, diphenhydramine and hydrocortisone with hydration. After restoration of vital signs, surgery was performed without complications.
Anaphylaxis; Bronchospasm; Erythema; Hydroxyethyl starch
Moyamoya disease is a rare progressive occlusive disease of the internal carotid arteries. We report a case of combined spinal-epidural anesthesia in a patient with Moyamoya disease presenting for Cesarean section. Hypotension associated with spinal anesthesia for Cesarean section is the most common and serious adverse effect despite the use of uterine displacement and volume preload. We continuously infused phenylephrine and ephedrine to prevent hypotension. The intraoperative hemodynamic state was stable. The patient had no significant postoperative complications.
Combined spinal-epidural anesthesia; Ephedrine; Moyamoya disease; Phenylephrine
To determine if the preanesthetic administration of ephedrine would prevent anesthesia-induced hypotension in dogs and cats, 10 cats were anesthetized with acepromazine, butorphanol, ketamine, and isoflurane, and 8 dogs were anesthetized with acepromazine, morphine, propofol, and halothane. Cats received ephedrine or saline 10 minutes after premedication. Dogs received ephedrine or saline at the time of premedication. Systolic arterial blood pressure, respiratory rate, heart rate, end-tidal CO2, O2 saturation, cardiac rhythm, and rectal temperature were recorded.
The systolic arterial pressure in cats receiving saline was significantly lower than baseline at 10 minutes after premedication, and systolic arterial pressure was < 80 mmHg for the duration of anesthesia. In cats receiving ephedrine, the systolic arterial pressure was significantly lower than baseline for the duration of anesthesia, but systolic arterial pressure was not < 80 mmHg until 25 min after induction. In dogs, systolic arterial pressure was significantly lower than baseline by 5 and 40 min after pre-medication in dogs receiving saline and ephedrine, respectively. There was no difference in heart rate, respiratory rate, end-tidal CO2, rectal temperature, O2 saturation, or cardiac rhythm among treatment groups. Prophylactic ephedrine delayed, but did not prevent, the onset of hypotension.
Phenylephrine bolus injection is an established technique to measure baroreflex sensitivity (BRS). This study quantified the relationship between the phenylephrine method and noninvasive measures of BRS and examined the effects of aging and hypertension on BRS. We also examined whether heart rate variability (HRV) provides as much information as does BRS.
BRS was determined by phenylephrine bolus (BRSphe), amyl nitrite inhalation (BRSamyl), Valsalva maneuver (BRSVals) and by time (BRS(+)) and spectral domain analysis (BRSLFα, 004–015Hz) of spontaneous blood pressure and R—R interval changes over the 5-min time period.
The phenylephrine method significantly correlated with other methods (BRSLFα R=0.54, BRS(+) R=0.55, BRSVals R=0.43 and BRSamyl R=0.39; P≤0.001). Each method underestimated the BRSphe by the factors 0.62, 0.64, 0.59 and 0.33, respectively; P value less than 0.001. Only BRSLFα was significantly different between normotensive and hypertensive patients in young [24.3±1.4 (n=40) vs. 12.2±2.3 (n=7)] and middle-aged [16.5±1.1 (n=71) vs. 10.8±1.1 (n=31) groups, respectively]. HRV in the high frequency band (0.15–0.40Hz) was significantly lower in young hypertensive patients than in normal controls (26±6.0 vs. 50±2.4, P<0.05).
Although all methods correlated with the phenylephrine technique, none of them could be used interchangeably with that technique. BRSLFα detected the baroreflex loss of hypertension most clearly, and BRSamyl did not differ among groups.
aging; baroreflex sensitivity; heart rate variability; hypertension; phenylephrine technique