Patient-ventilator asynchrony is a major cause of difficult weaning from mechanical ventilation. Neurally adjusted ventilatory assist (NAVA) is reported useful to improve the synchrony in patients with sustained low lung compliance. However, the role of NAVA has not been fully investigated.
The patient was a 63-year-old Japanese man with acute respiratory distress syndrome secondary to respiratory infection. He was treated with extracorporeal membrane oxygenation for 7 days and survived. Dynamic compliance at withdrawal of extracorporeal membrane oxygenation decreased to 20 ml/cmH2O or less, but gas exchange was maintained by full support with assist/control mode. However, weaning from mechanical ventilation using a flow trigger failed repeatedly because of patient-ventilator asynchrony with hypercapnic acidosis during partial ventilator support despite using different types of ventilators and different trigger levels. Weaning using NAVA restored the regular respiration and stable and normal acid-base balance. Electromyographic analysis of the diaphragm clearly showed improved triggering of both the start and the end of spontaneous inspiration. Regional ventilation monitoring using electrical impedance tomography showed an increase in tidal volume and a ventilation shift to the dorsal regions during NAVA, indicating that NAVA could deliver gas flow to the dorsal regions to adjust for the magnitude of diaphragmatic excursion. NAVA was applied for 31 days, followed by partial ventilatory support with a conventional flow trigger. The patient was discharged from the intensive care unit on day 110 and has recovered enough to be able to live without a ventilatory support for 5 h per day.
Our experience showed that NAVA improved not only patient-ventilator synchrony but also regional ventilation distribution in an acute respiratory distress patient with sustained low lung compliance.
Neurally adjusted ventilatory assist; Compliance; Patient-ventilator synchrony; Electromyography; Electrical impedance tomography; Ventilation distribution
Aim of Study:
In Surviving Sepsis Campaign Guidelines 2012, noradrenalin (NA) is recommended as a first choice vasopressor. Although vasopressin (VP) is recommended for the treatment of NA-resistant septic shock, the optimal parameters for its administration remain unclear.
Materials and Methods:
We conducted a retrospective study to evaluate the clinical outcomes of the administration of VP to adult septic shock patients who were undergoing high-dose NA (≥0.25 μg/kg/min) therapy in our Intensive Care Unit between January 2010 and December 2013. We defined high-dose NA as a dose of >0.25 μg/kg/min, based on the definition of low-dose NA as a dose of 5–14 μg/min because the average body weight of the patients in this study was 53.0 kg.
Among 29 patients who required the administration of high-dose NA, 18 patients received VP. Although the patient background physiological conditions and NA dose did not differ between the two groups, the survival rate of the VP-treated patients was significantly lower (33%) than that of the patients who were managed with a high-dose of NA-alone (82%) (P = 0.014). The lactate clearance did not change after the administration of VP, whereas it improved when in NA treatment alone.
The results suggest that the administration of VP did not improve the mortality among septic shock patients when administered in addition to high-dose NA.
Lactate clearance; noradrenalin; septic shock; vasopressin
Electrical impedance tomography (EIT) is a noninvasive technique used to assess regional gas distribution in the lung. We experienced a patient with acute cor pulmonale during high positive-pressure ventilation for the treatment of severe acute respiratory distress syndrome. Prone positioning was beneficial for unloading the right ventricle for treatment of acute cor pulmonale. EIT played a role in detecting lung derecruitment at the patient’s bedside. Impedance distribution in ventral, mid-ventral, mid-dorsal, and dorsal layers before and 20 min after the start of prone positioning was 9, 48, 44, and 0 %, and 10, 25, 48, and 16 %, respectively. Lung recruitment monitored by EIT paralleled the improvement of PaO2/FIO2 from 123 to 239 mmHg. Timing of termination of prone positioning and ventilator settings such as lowering positive end-expiration pressure was determined to maintain dorsal recruitment as seen by EIT. The patient was weaned from mechanical ventilation on day 32 and discharged on day 200. EIT assessed the effects of prone positioning with real-time dynamic imaging and guided less injurious mechanical ventilation in a patient with acute cor pulmonale with dorsal lung derecruitment.
Acute respiratory distress syndrome; Acute cor pulmonale; Prone positioning; Electrical impedance tomography
Caudal block is easily performed because the landmarks are superficial. However, the sacral hiatus is small and shallow in pediatric patients. In the present study, we evaluated under general anesthesia whether the distance between the bilateral superolateral sacral crests increased with growth, whether an equilateral triangle was formed between the apex of the sacral hiatus and the bilateral superolateral sacral crests, and whether expansion of the epidural space could be confirmed by ultrasound.
This prospective observational study included 282 children who were ASA I–II. Under general anesthesia, each patient was placed in the lateral bent knees position, and the attending anesthesiologist drew an equilateral triangle and measured the distance between the bilateral superolateral sacral crests along a line forming the base of the triangle. Then the sacral hiatus was identified by ultrasound. Differences of the distance between the anatomical landmarks measured by the anesthetist and by ultrasound were evaluated.
Two patients were excluded because the superolateral sacral crests and sacral hiatus could not be palpated. The base of the triangle increased in proportion to age up to 10 years old, with a significant correlation between age and the length of the base (Spearman’s r value = 0.97). The triangle was not an equilateral triangle under 7 years old. The sacral hiatus could be identified by ultrasound and we could confirm expansion of the epidural space in all patients.
We observed a correlation between age and the length of the triangle base in children under 10 years old. Although detection of the anatomical landmarks by palpation differed from identification by ultrasound in pediatric patients, performing ultrasound is important. Epinephrine should be added to the anesthetic to avoid complications.
Current Controlled Trials UMIN000017898. Registered 14 June 2015. Date of protocol fixation was 1st December, 2008 and Anticipated trial start date was 5th January, 2009.
Caudal epidural anesthesia; Ultrasound; Anatomical landmark
Anaesthetists possibly contribute to the spread of infections during anaesthesia. The adenosine triphosphate (ATP) bioluminescence assay is an easy-to-perform, on-the-spot assay that provides objective data; therefore, using the LuciPac®Pen and the Lumitester PD-20®System, we assessed contamination of the working environment of anaesthetists before and after surgery as well as their hands at the time of each procedure during induction and extubation. Similarly, cleanliness of the operating room was evaluated using this assay to determine whether it is useful to assess the effectiveness of the routine cleaning protocols followed after surgery. ATP concentrations in the working environment of anaesthetists and their hands increased during surgery. In addition, ATP concentrations within the working environment decreased after routine cleaning with ethanol or accelerated hydrogen peroxide; however, there were no differences in the number of sites with ATP concentrations >500 relative light units before and after cleaning. This method is useful to evaluate contamination of the working environment of anaesthetists; nevertheless, it is prudent to evaluate the effectiveness of routine cleaning protocols because ATP bioluminescence assays are influenced by the use of various disinfectants at varying concentrations.
Adenosine triphosphate bioluminescence assay; hands of anaesthetists; routine cleaning; working environment of anaesthetists
We are reporting the case of a 56-year-old woman who developed loss of consciousness during awake craniotomy. A thin subdural haematoma in the contralateral side of the craniotomy was identified with intraoperative magnetic resonance imaging and subsequently removed. Our case indicates that contralateral acute subdural haematoma could be a cause of deterioration of the conscious level during awake craniotomy.
We evaluated the safety and efficacy of long-term administration of dexmedetomidine in patients in the intensive care unit (ICU). Primary endpoint was the incidence of hypotension, hypertension, and bradycardia. Secondary endpoints were withdrawal symptoms, rebound effects, the duration of sedation with Richmond Agitation-Sedation Scale (RASS) ≤ 0 relative to the total infusion time of dexmedetomidine, and the dose of additional sedatives or analgesics.
Dexmedetomidine 0.2–0.7 μg/kg/h was continuously infused for maintaining RASS ≤ 0 in patients requiring sedation in the ICU. Safety and efficacy of short-term (≤24 h) and long-term (>24 h) dexmedetomidine administration were compared.
Seventy-five surgical and medical ICU patients were administered dexmedetomidine. The incidence of hypotension, hypertension, and bradycardia that occurred after 24 h (long-term) was not significantly different from that occurring within 24 h (short-term) (P = 0.546, 0.513, and 0.486, respectively). Regarding withdrawal symptoms, one event each of hypertension and headache occurred after the end of infusion, but both were mild in severity. Increases of mean arterial blood pressure and heart rate after terminating the infusion of dexmedetomidine were not associated with the increasing duration of its infusion. The ratio of duration with RASS ≤ 0 was ≥ 85 % until day 20, except day 9 (70 %) and day 10 (75 %). There was no increase in the dose of additional sedatives or analgesics after the first 24-h treatment period.
Long-term safety of dexmedetomidine compared to its use for 24 h was confirmed. Dexmedetomidine was useful to maintain an adequate sedation level (RASS ≤ 0) during long-term infusion.
Dexmedetomidine; Long term; Sedation; Intensive care unit; Withdrawal
The first purpose of this study was to determine the incidence of postoperative nausea and/or vomiting (PONV) 0–48 h after anesthesia at a Japanese cancer center. The second purpose of this study was to collect information on PONV risk factors, independently, in the categories of patient-related, anesthesia-related, and surgery-related factors.
The frequency of nausea and vomiting was prospectively investigated from 0 to 48 h after anesthesia in 1645 patients (11–94 years of age) at a single medical institution. The occurrence of nausea and vomiting and the use of antiemetics were recorded up to 48 h after anesthesia. Patient-related, anesthesia-related, and surgery-related factors were also recorded and submitted to multiple logistic regression analysis to determine the relationship of these factors to nausea and vomiting.
The incidences of nausea and vomiting from 0 to 24 h after anesthesia were 40 and 22 %, respectively. The incidences 24–48 h after anesthesia were 10 and 3 %, respectively. Female sex, previous history of PONV, prolonged anesthesia, and remifentanil use during surgery were identified as risk factors for both nausea and vomiting. The use of a volatile anesthetic, use of fentanyl during surgery, postoperative use of opioids, nonsmoking status, and drinking alcohol on 4 or fewer days per week were identified as risk factors for nausea alone.
The incidence of and risk factors for PONV at a Japanese cancer center according to this study are comparable to those reported elsewhere.
Postoperative nausea and vomiting; PONV; Prospective study; Risk factors; Japan
It has been reported that recently developed circulating-water garments transfer more heat than a forced-air warming system. The authors evaluated the hypothesis that circulating-water leg wraps combined with a water mattress better maintain intraoperative core temperature ≥36°C than either forced-air warming or carbon-fiber resistive heating during major abdominal surgery.
Thirty-six patients undergoing open abdominal surgery were randomly assigned to warming with: (1) circulating-water leg wraps combined with a full-length circulating-water mattress set at 42°C, (2) a lower-body forced-air cover set on high (≈43°C), and (3) a carbon-fiber resistive-heating cover set at 42°C. Patients were anesthetized with general anesthesia combined with continuous epidural analgesia. The primary outcome was intraoperative tympanic-membrane temperature ≥36°C.
In the 2 h after anesthesia induction, core temperature decreased 1.0 ± 0.5°C in the forced-air group, 0.9 ± 0.2°C in the carbon-fiber group, and 0.4 ± 0.4°C in the circulating-water leg wraps and mattress group (P < 0.05 vs. forced-air and carbon-fiber heating). At the end of surgery, core temperature was 0.2 ± 0.7°C above preoperative values in the circulating-water group but remained 0.6 ± 0.9°C less in the forced-air and 0.6 ± 0.4°C less in the carbon-fiber groups (P < 0.05 vs. carbon fiber).
The combination of circulating-water leg wraps and a mattress better maintain intraoperative core temperature than did forced-air and carbon-fiber warming systems.
Temperature; Hypothermia; Circulating-water garment; Carbon fiber; Forced air
The present study was aimed to test a hypothesis that individuals with functional ankle instability (FAI) underestimate the joint angle at greater plantarflexion and inversion. Seventeen males with unilateral FAI and 17 controls (males without FAI) consented for participation in this IRB-approved, case-control study. Using a passive reproduction test, we assessed ankle joint position sense (JPS) for test positions between 30 and -10 degrees plantarflexion with an inclement of 10 degrees with or without 20° inversion at each plantarflexion angle. The constant error (CE) was defined as the value obtained by subtracting the true angle of a test position from the corresponding perceived angle. At plantarflexed and inverted test positions, the CE values were smaller in negative with greater in the FAI group than in the control group. That is, in the FAI group, the FAI group underestimated the true plantarflexion angle at combined 30° plantarflexion and 20° inversion. We conclude that the ankle with FAI underestimate the amount of plantarflexion, which increases the chance of reaching greater planterflexion and inversion than patients' intention at high risk situations of spraining such as landing.
Key pointsJoint position sense (JPS) of the ankle with functional ankle instability was investigated utilizing a passive reproduction test.The FAI group demonstrated greater error of the joint position than the control group only when the ankle was positioned at combined inversion and plantarflexion.The FAI group underestimated plantarflexion angle when the ankle was placed at combined inversion and plantarflexion.
Functional ankle instability; lateral ankle sprain; proprioception; joint position sense; constant error
Although the difficulty of tracheal intubation in the lateral position has not been systematically evaluated, airway loss during surgery in a laterally positioned patient may have hazardous consequences. We explored whether the intubating laryngeal mask airway (ILMA) facilitates tracheal intubation in patients with normal airway anatomy, i.e., Mallampati grade ≤ 3 and thyromental distance ≥ 5 cm, positioned in the lateral position. And we evaluated whether this technique can be used as a rescue when the airway is lost mid-case in laterally positioned patients with respect to success rate and intubation time. Anesthesia was induced with propofol, fentanyl, and vecuronium in 50 patients undergoing spine surgery for lumbar disk herniation (Lateral) and 50 undergoing other surgical procedures (Supine). Patients having disk surgery (Lateral) were positioned on their right or left sides before induction of general anesthesia, and intubation was performed in that position. Patients in control group (Supine) were anesthetized in supine position, and intubation was performed in that position. Intubation was performed blindly via an ILMA in both groups. The time required for intubation and number and types of adjusting maneuvers employed were recorded. Data were compared by Mann-Whitney U, Fisher’s exact, chi-square, or unpaired t-tests, as appropriate. Data presented as mean (SD). Demographic and airway measures were similar in the two groups, except for mouth opening which was slightly wider in patients in the lateral position: 5.1 (0.9) vs. 4.6 (0.7) cm. The time required for intubation was similar in each group (≈25 s), as was intubation success (96%). We conclude that blind intubation via an ILMA offers a frequent success rate and a clinically acceptable intubation time (< one min) even in the lateral position.
Blind intubation via the intubating laryngeal mask airway (ILMA) offers a high success rate and a clinically acceptable intubation time even in patients in the lateral position.
Equipment: intubating laryngeal mask airway; Position: lateral: Intubation (Tracheal): technique
Reported effect-site concentrations of propofol at loss of consciousness and recovery of consciousness vary widely. Thus, no single concentration based on a population average will prove optimal for individual patients. We therefore tested the hypothesis that individual propofol effect-site concentrations at loss and return of consciousness are similar. Propofol effect-site concentrations at loss and recovery of consciousness were estimated with a target-control infusion system in 20 adults. Propofol effect-site concentrations were gradually increased until the volunteers lost consciousness (no response to verbal stimuli); unconsciousness was maintained for 15 minutes, and the volunteers were then awakened. This protocol was repeated three times in each volunteer. Our major outcomes were the concentration producing unconsciousness and the relationship between the estimated effect-site concentrations at loss and recovery of consciousness. The target effect-site propofol concentration was 2.0 ± 0.9 at loss of consciousness and 1.8 ± 0.7 at return of consciousness (P < 0.001). The average difference between individual effect-site concentrations at return and loss of consciousness was only 0.17 ± 0.32 μg/mL (95% confidence interval for the difference 0.09 to 0.25 μg/mL). Our results thus suggest that individual titration to loss of consciousness is an alternative to dosing propofol on the basis of average population requirements.
Propofol can be titrated to the concentration that produces consciousness in individual patients. Provided that the propofol effect-site concentration does not much exceed the concentration initially required to produce unconsciousness, patients can be expected to awaken quickly upon completion of the procedure.
An intubating laryngeal mask airway (ILMA) facilitates tracheal intubation with the neck in neutral position, which is similar to the neck position maintained by a rigid cervical collar. However, a cervical collar virtually obliterates neck movement, even the small movements that normally facilitate airway insertion. We therefore tested the hypothesis that the ILMA facilitates tracheal intubation even in patients wearing a rigid cervical collar. In 50 cervical spine surgery patients with a rigid Philadelphia collar in place and 50 general surgery patients under general anaesthesia, we performed blind tracheal intubation via an ILMA. The time required for intubation, intubation success rate, and numbers and type of adjusting manoeuvres employed were recorded. Inter-incisor distance was significantly smaller (4.1 [0.8] cm vs. 4.6 [0.7] cm, mean [SD], P<0.01) and Mallampati scores were significantly greater (P<0.001) in the collared patients. ILMA insertion took longer (30  vs. 22  seconds), more patients required 2 insertion attempts (15 vs. 3; P<0.005), and ventilation adequacy with ILMA was worse (P<0.05) in collared patients. However, there were no significant differences between the collared and control patients in terms of total time required for intubation (60  vs. 50  seconds), number of intubation attempts, overall intubation success rate (96 vs. 98%), or the incidence of intubation complications. Blind intubation through an ILMA is thus a reasonable strategy for controlling the airway in patients who are immobilized with a rigid cervical collar, especially when urgency precludes a fiberoptic approach.
anaesthesia; intubation; tracheal; laryngeal mask; cervical collar