Anaphylaxis during anaesthesia: Indian scenario.

BACKGROUND AND AIMS: Anaphylaxis during anaesthesia is a rare but serious problem. In contrast to the developed countries where databases of perianaesthetic anaphylaxis are preserved, none exist in India. We conducted a survey amongst Indian anaesthesiologists to study the incidence and aetiology of anaphylaxis during anaesthesia in India. METHODS: A written questionnaire comprising 20 items was mailed electronically or distributed personally to 600 randomly selected Indian anaesthesiologists. The responses were compiled and analysed. RESULTS: We received responses from 242 anaesthesiologists. One hundred and sixty-two (67%) anaesthesiologists had encountered anaphylaxis during anaesthesia. Anaesthetic drugs led to 40% of reactions, and 60% of reactions were attributed to non-anaesthetic drugs. Opioids were the most common anaesthetic drugs implicated in anaphylaxis during anaesthesia, and non-depolarising muscle relaxants were the second most commonly implicated agents. Colloids, antibiotics and blood transfusion were the common non-anaesthetic agents thought to be responsible for anaphylactic reactions during anaesthesia. There were five deaths due to anaphylaxis during anaesthesia. Only 10% of anaesthesiologists ordered for allergy testing subsequently though 38% of anaesthesiologists had access to allergy testing facilities. CONCLUSIONS: Our survey reveals that two-thirds of participating Indian anaesthesiologists had witnessed anaphylaxis during anaesthesia. Commonly implicated anaesthetic drugs were opioids and non-depolarising muscle relaxants while colloids, antibiotics and blood transfusion were the common non-anaesthetic agents causing anaphylactic reactions during anaesthesia. Further, our survey reveals low utilisation and paucity of referral allergy centres to investigate suspected cases of anaphylaxis during anaesthesia.

ProSeal laryngeal mask airway™ insertion in the prone position: Optimal utilization of operation theatre personnel and time?

BACKGROUND: Positioning an anesthetized patient prone is challenging with regard to manpower requirement, time to surgical readiness and airway management. The ProSeal laryngeal mask airway™ (PLMA) is emerging as a suitable alternative, both as a primary and a rescue airway device to the tracheal tube (TT) for patients undergoing surgery in the prone position. MATERIALS AND METHODS: In this prospective randomized study, 70 patients scheduled to undergo pilonidal sinus excision in prone position were allocated to two groups of 35 patients each, depending on the position of the patient at induction and device placement: Group S (device placed while supine) and Group P (device placed while prone). We compared the manpower requirement, time to surgical readiness, efficacy and safety of the PLMA for airway management in the two groups. RESULTS: The number of personnel [5 (4-6) vs. 3 (3-3); P < 0.001] required for positioning the patient and surgical readiness time (22.1 ± 3 vs. 5.9 ± 0.9 min; P < 0.001) was higher in group S. There was no difference between the two groups with regard to efficacy and safety of the PLMA. Incidence of blood on the PLMA cuff and sore throat was comparable in the two groups (P = 1.000). CONCLUSION: We conclude that induction and placing the PLMA in the prone position by experienced users require fewer personnel and reduces surgical readiness time.

Hemodynamics and early recovery characteristics of desflurane versus sevoflurane in bariatric surgery.

CONTEXT: Morbidly obese patients are prone for intraoperative hemodynamic disturbances and postoperative airway complications. AIM: Comparison of intraoperative hemodynamics and postoperative recovery characteristics of desflurane versus sevoflurane in morbidly obese patients undergoing laparoscopic bariatric surgery. SETTINGS AND DESIGN: Randomized controlled trial. MATERIALS AND METHODS: After institutional ethics committee approval and written informed consent, 40 morbidly obese patients (BMI > 35 kg/m(2)) were randomized to receive desflurane or sevoflurane as part of a standardized general anesthesia technique. Volatile anesthetic concentration was titrated to maintain electroencephalographic bispectral index score (BIS) in the range of 40-60. Mean arterial pressure (MAP) and heart rate (HR) were recorded preoperatively, at induction and intubation, then at regular intervals. After extubation, early recovery was recorded by time to emergence and orientation to time and place. In post anesthesia care unit, intermediate recovery was assessed by modified Aldrete Score and Digit Symbol Substitution Test (DSST). RESULTS: Intraoperative MAP and HR did not differ between the two groups (P > 0.05). The time to response to painful stimuli, obeying verbal commands and spontaneous eye opening was shorter (P = 0.001) and modified Aldrete Score was higher after desflurane anesthesia than after sevoflurane anesthesia (P = 0.049). DSST also returned towards normal faster after desflurane (28.50 ± 6.30 min vs. 35.0 ± 5.62 min, P = 0.03). CONCLUSIONS: Both desflurane and sevoflurane produce similar hemodynamic changes but the immediate and intermediate recovery was significantly faster after desflurane thus contributing to fast tracking and early discharge of patients.

ProSeal™ laryngeal mask airway cuff pressure changes with and without use of nitrous oxide during laparoscopic surgery.

BACKGROUND: The ProSeal™ laryngeal mask (PLMA) is increasingly being used as an airway device for laparoscopic surgery. Its silicone cuff allows diffusion of nitrous oxide, carbon dioxide and other gases with resultant rise in its intracuff pressure during anesthesia. The present study was designed to investigate the intracuff pressure changes during anesthesia with and without nitrous oxide in patients undergoing laparoscopic surgery lasting up to two hours. MATERIALS AND METHODS: One hundred patients, American Society of Anesthesiologists physical status 2 and 3, undergoing general anesthesia with muscle paralysis, were randomized into two groups of 50 patients each to receive an anesthetic gas mixture containing either oxygen and nitrous oxide (group N) or oxygen and air (group A). Following insertion of an appropriate size PLMA, its cuff was inflated with air to an intracuff pressure of 45 mm Hg. The cuff pressure was measured every 10 minutes for the entire course of anesthesia. The position of the device was also assessed fiberoptically and postoperative airway complications were recorded. RESULTS: The maximum intracuff pressure recorded in group N was 103 ± 4.7 mm Hg vs. 45.5 ± 1.5 mm Hg in group A. The percentage rise in cuff pressure every 10 minutes was also highly significant (P < 0.001) being maximum in first 10 min in group N. The incidence of postoperative airway complications was comparable between the two groups. CONCLUSION: The results of this study demonstrate that the intracuff pressure of the PLMA increases progressively over time when the breathing gas mixture contains nitrous oxide.

PLMA vs. I-gel: A Comparative Evaluation of Respiratory Mechanics in Laparoscopic Cholecystectomy.

BACKGROUND: Supraglottic airway devices (SADs), such as ProSealTM laryngeal mask airway (PLMA), which produce high oropharyngeal seal pressure (OSP) and have the facility for gastric decompression have been used in laparoscopic procedures. i-gel is a new SAD which shares these features with the PLMA. This study was designed to compare the respiratory mechanics of these two devices during positive pressure ventilation in anaesthetised adult patients undergoing laparoscopic cholecystectomy. PATIENTS #ENTITYSTARTX00026; METHODS: The study included 60 ASA I-II adult patients scheduled for laparoscopic cholecystectomy. The patients were randomized to two groups of 30 each, with either PLMA or i-gel as their airway device. Anaesthesia and premedication were standardized for both the groups. In addition to routine monitoring, neuromuscular monitoring with TOF ratio, OSP and respiratory mechanics monitoring (dynamic compliance, resistance, work of breathing, measured minute ventilation and peak airway pressures) were employed. Fibreoptic evaluation of positioning of the devices and adverse events related to them were also compared. RESULTS: The OSP (cm H2O) were higher for PLMA (38.9 vs. 35.6, P=0.007). The respiratory mechanics parameters using the two devices were comparable apart from the dynamic compliance, which was significantly higher with i-gel (P < 0.05). Malrotation was higher with i-gel than with PLMA (15 vs. 5, P = 0.006). CONCLUSION: The PLMA formed a better seal while the dynamic compliance was higher with the i-gel. Both devices provided optimal ventilation and oxygenation and the adverse events were also comparable.

A prospective randomized double blind study to evaluate the effect of infusion of amino Acid enriched solution on recovery from neuromuscular blockade.

SUMMARY: Hypothermia is a common occurrence under anaesthesia and may prolong the duration of action of neuromuscular blockade. By limiting fall in temperature, an infusion of amino acid enriched solution may speed the recovery from neuromuscular blockade. We studied 60 ASA Grade - I/II patients of aged between 20 to 60 years scheduled for elective surgery under general anaesthesia. The patients were randomly divided into four groups to receive amino acid infusion with vecuronium bromide AV, normal saline with vecuronium bromide(CV), amino acid with atracurium besylate(A-At) and normal saline with atracurium besylate(C-At). Although there was a significantly lesser decrease in the core temperature from the baseline in all the patients receiving amino acid infusion (p<0.05), it significantly reduced the time to 25% recovery from the time of injection of vecuronium only. (60.59 +/- 11.39 in CV vs 51 +/- 14.72 min in AV) (P < 0.05), and not for atracurium.

A prospective randomized study comparing two techniques of perioperative blood conservation: isovolemic hemodilution and hypervolemic hemodilution.

UNLABELLED: We compared hypervolemic hemodilution (HVH) and isovolemic hemodilution (IVH) as means of perioperative blood conservation under standardized conditions. Thirty ASA status I/II adults slated for orthopedic, ear-nose-throat, or general surgery with expected blood loss of >500 mL underwent either IVH (n = 15) or HVH (n = 15). They were hemodiluted to a hematocrit (Hct) of 25% by blood withdrawal and simultaneous polygeline (Hemaccel((R))) infusion (IVH) or by infusing polygeline without blood withdrawal, thus creating hypervolemia (HVH). Further blood loss to a Hct of 20% was allowed before autologous/allogeneic blood transfusion to aim for a 24-h postoperative Hct of > or =25%. Systolic blood pressure (P = 0.0107) and central venous pressure (P = 0.0281) were significantly higher during HVH. The mean difference (MD) between the target postdilution Hct of 25% and the Hct achieved was not statistically significant in either group (MD [95% confidence interval; CI], 0% [-0.7% to 0.7%] for IVH and 0.6% [-0.1% to 1.3%] for HVH). The actual amount of allogeneic blood used was similar in the two groups, with an MD (95% CI) of -7 (-326 to 312), and was significantly less than the corresponding projected amount (MD [95% CI], -581 mL [-753 to -409 mL] in IVH; -376 mL [-531 to -221] in HVH). The two techniques were similar in time taken (MD [95% CI] = 7 min [-0.5 to 14.5 min]), cost incurred (MD [95% CI] = $1.7 (-$4.10 to $7.50]), and volumes of polygeline used (MD [95% CI] = -6 mL/kg body weight [-16 to 4 mL/kg body weight]). This study found IVH and HVH comparable in significantly reducing perioperative allogeneic blood requirements, time needed, and cost incurred. The formula used for achieving the desired HVH appears promising. IMPLICATIONS: Both hypervolemic hemodilution (HVH) and isovolemic hemodilution (IVH) claim to reduce red blood cell loss during surgery by diluting the patient's blood. This study found both comparable in significantly reducing the exposure to bank blood in the perioperative period, the time needed, and the cost incurred. HVH, being simpler, because it does not involve blood withdrawal, appeared superior to IVH in the healthy adults studied. Larger studies are needed to substantiate the results.