Jerry Paul

Safety and efficacy of low molecular weight dextran (Dextran 40) in head and neck free flap reconstruction

BACKGROUND Antithrombotic agents have been used in microvascular surgeries. Low molecular weight dextran (dextran 40), though used, is not without complications. METHODS Retrospective analysis of 172 consecutive flaps. A comparison was made between two groups of patients (86 flaps each) with and without the use of dextran 40, in terms of safety and efficacy. RESULTS The free flap survival rate was 95.9%. The flap survival rates were comparable between the groups. Total flap loss in Group A (patients who received dextran 40) was 3.5% compared with 2.3% in Group B (patients who did not receive dextran 40) (p = 1.00). There was no statistically significant difference in the incidence of thrombotic flap complications between the groups. None of the patients developed acute respiratory distress syndrome or required prolonged ventilator support. No patient had dextran-related anaphylactoid reactions. Thirty-eight patients (43.7%) in Group A had postoperative atelectasis and 21 (25.6%) patients in Group B had this complication (p = 0.01). Six patients in Group A developed postoperative pneumonia, and five patients in Group B developed this complication (p = 0.93). CONCLUSIONS Though dextran 40 did not result in any significant adverse local or systemic complications, it is not useful as a postoperative antithrombotic agent in head and neck oncologic reconstruction with free tissue transfer.

Evaluation of endotracheal intubating conditions without the use of muscle relaxants following induction with propofol and sevoflurane in pediatric cleft lip and palate surgeries

Background and Aims: Children with facial clefts are usually difficult to intubate and it is considered safer to keep them spontaneously breathing while securing the airway. This prospective comparative study was conducted to evaluate endotracheal intubating conditions in pediatric patients undergoing cleft surgeries, without the use of muscle relaxants following induction with propofol and sevoflurane. Materials and Methods: Sixty patients aged 1month to 3 years, were randomly allocated into two equal groups. Anesthesia was induced with sevoflurane 8% in oxygen in group 1 and with propofol 3 mg/kg in group 2. Laryngoscopy and intubation were attempted 150 s after induction in both groups and ease of laryngoscopy, position of vocal cords, degree of coughing, jaw relaxation, and limb movements were assessed and scored. Total score of 5 was considered excellent, 6-10 good, 11-15 poor, and 16-20 bad. Total score ≤ 10 was considered clinically acceptable, and >10 as clinically unacceptable. Chi-square and Wilcoxon Mann-Whitney tests were used to analyze data. Results: There was no significant difference between groups when ease of laryngoscopy was compared. Sevoflurane induced patients had significantly better position of vocal cords at intubation and the propofol group had significantly more episodes of coughing. Significantly less number of patients had limb movements in sevoflurane group. There was no significant difference in degree of jaw relaxation between groups. The sevoflurane group had significantly better total scores and clinically acceptable intubating conditions. Conclusion: Sevoflurane 8% in oxygen provides clinically acceptable intubating conditions without use of muscle relaxants in pediatric cleft patients.

Are active warming measures required during paediatric cleft surgeries

Background: During paediatric cleft surgeries intraoperative heat loss is minimal and hence undertaking all possible precautions available to prevent hypothermia and use of active warming measures may result in development of hyperthermia. This study aims to determine whether there will be hyperthermia on active warming and hypothermia if no active warming measures are undertaken. The rate of intraoperative temperature changes with and without active warming was also noted. Methods: This study was conducted on 120 paediatric patients undergoing cleft lip and palate surgeries. In Group A, forced air warming at 38°C was started after induction. In Group B, no active warming was done. Body temperature was recorded every 30 min starting after induction until 180 min or end of surgery. Intragroup comparison of variables was done using Paired sample test and intergroup comparison using independent sample t-test. Results: In Group A, all intraoperative temperature readings were significantly higher than baseline. In Group B, there was a significant reduction in temperature at 30 and 60 min. Temperature at 90 min did not show any significant difference, but further readings were significantly higher. Maximum rise in temperature occurred in Group A between 120 and 150 min and maximum fall in temperature in Group B was seen during first 30 min. Conclusion: In pediatric cleft surgeries, we recommend active warming during the first 30 minutes if the surgery is expected to last for <2h, and no such measures are required if the expected duration is >2h.

Comparison of margin of safety following two different techniques of preoxygenation

Background and Aims: Shortening the duration of efficacious preoxygenation would provide benefit in emergency situations like fetal distress etc. This study aims to compare the margin of safety following preoxygenation using 8 vital capacity breaths (VCB) in 1 min and tidal volume breathing (TVB) for 3 min, by assessing changes in PaO2 and apnea induced desaturation time. Material and Methods: Patients were randomly divided into Group A and B. In Group A, 3 min of TVB using O2 flow of 5 l/min and in Group B, 8 VCB in 60 s using O2 flow of 10 l/min were used. Anesthesia was induced in all patients with propofol followed by succinylcholine 2 mg/kg intravenously. Mask ventilation was not done and following intubation endotracheal tube was kept open to atmosphere. The time taken for the patients to desaturate to 90% was noted and immediately ventilation was resumed. Arterial blood gas samples were taken while patients were breathing room air, immediately after preoxygenation and at 90% desaturation. Results: Baseline PaO2 of both the groups were comparable. After preoxygenation Group B had a significantly high PaO2 value than Group A (439.05 ± 62.20 vs. 345.16 ± 20.80). At 90% desaturation there was no significant difference between groups. Group B showed a significantly high apnea induced desaturation time when compared to Group A (6.87 ± 1.78 vs. 3.47 ± 0.38 min). Conclusions: Preoxygenation by 8 VCB in 1 min provides a greater margin of safety, as it results in a significantly high PaO2 with an almost doubled apnea induced desaturation time, in comparison with TVB for 3 min.

Effectiveness of single dose conivaptan for correction of hyponatraemia in post-operative patients following major head and neck surgeries

Background and Aims: Conivaptan, a vasopressin receptor antagonist, is commonly used for the treatment of euvolaemic, hypervolaemic hyponatraemia. Usually, an intravenous (IV) bolus followed by infusion is administered for many days. We decided to assess the effectiveness of single dose conivaptan for correction of hyponatraemia in post-operative patients. Methods: This was a prospective, randomised trial conducted in 40 symptomatic post-operative Intensive Care Unit (ICU) patients with a serum sodium level of ≤130 mEq/L. Group A patients received IV conivaptan 20 mg over 30 min, whereas in group B infusion of 3% hypertonic saline was started as an infusion at the rate of 20-30 ml/h. Serum sodium levels were measured at 12, 24, 48 and 72 h and the daily fluid balance was measured for 3 days. The Chi-square test, Wilcoxon signed rank test and Mann-Whitney tests were used as applicable. Results: The serum sodium levels before initiating treatment were comparable between groups. However, subsequent sodium levels at 12, 24 and 48 h showed significantly high values in group A. Though at 72 h the mean sodium value was high in group A, it was not statistically significant. Group A showed a significantly high fluid loss on day 1, 2 and 3. The mean volume of hypertonic saline required in group B showed a steady decline from day 1 to 3 and only 13 patients required hypertonic saline on the 3 rd day. Conclusion: Single dose conivaptan is effective in increasing serum sodium levels in post-operative ICU patients up to 72 h associated with a significant negative fluid balance.

Effect of pre-operative discontinuation of angiotensin-converting enzyme inhibitors or angiotensin II receptor antagonists on intra-operative arterial pressures after induction of general anesthesia.

Context: Medical guidelines advise perioperative continuation many antihypertensives, but discontinuing angiotensin antagonists before surgery. Aims: This study is aimed to determine the effect of preoperative discontinuation of angiotensin-converting enzyme inhibitors (ACEI) or angiotensin II receptor antagonists (ARA) on intra-operative blood pressure after induction of general anesthesia. Settings and Design: The study was a randomized, prospective and double blinded one done in 60 hypertensive patients, receiving these drugs. Materials and Methods: Patients were randomized into two equal groups. In Group A, ACEI or angiotensin II receptor antagonist was stopped the day before surgery, but in Group B it was continued. Anesthetic management was standardized by a study protocol. Systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) were measured just before induction and after induction at 1 min, 3, 5, 10, 15, 30, 45 and 60 min. Statistical Analysis: Difference between means and difference between two proportions was analyzed using Normal test for means and corresponding P values were calculated. Results: Pre-induction SBP, DBP and MAP were comparable between groups. However when the pre-induction values were compared with subsequent readings at 3, 5, 10, 15, 30, 45 and 60 min, it was found that there was a significant reduction in SBP, DBP and MAP in Group B up to 60 min. Conclusions: Intraoperative hemodynamics can be safely managed when ACEI or ARA are withheld on the day of surgery.

Effectiveness of transnasal humidified rapid-insufflation ventilatory exchange versus traditional preoxygenation followed by apnoeic oxygenation in delaying desaturation during apnoea: A preliminary study

Background and Aims: Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) during apnoea has shown to delay desaturation. The primary objective was to compare time to desaturate to <90% during apnoea with THRIVE versus traditional preoxygenation followed by apnoeic oxygenation. Methods: This prospective, randomised, single-blinded study was conducted in 10 adult patients presenting for direct laryngoscopy under general anaesthesia without endotracheal intubation. Group P patients were preoxygenated with 100% oxygen, and in Group H, high-flow humidified oxygen was delivered using nasal cannula for 3 min. After induction and neuromuscular blockade, time to desaturate to 90%, while receiving apnoeic oxygenation, was noted. Chi-square test and Mann–Whitney tests were used. Results: Group H had a significantly longer apnoea time as compared to Group P (796.00 ± 43.36 vs. 444.00 ± 52.56 s). All patients in Group H continued to have nearly 100% saturation even at 12 min of apnoea. However, in Group P, 80% of patients desaturated to <90% after 6 min of apnoea. Baseline blood gases, that following preoxygenation and at 3 min of apnoea time were comparable in both groups. At 6 min, Group H had a significantly higher PaO2 (295.20 ± 122.26 vs. 135.00 ± 116.78) and PaCO2 (69.46 ± 7.15 vs. 59.00 ± 4.64). Group H continued to have a PaO2of >200 mmHg even at 12 min of apnoea with a significant rise in PaCO2along with fall in pH after 6 min. Conclusion: During apnoeic periods time to desaturate to <90% was significantly prolonged with use of THRIVE.

Effect of inhaled budesonide suspension, administered using a metered dose inhaler, on post-operative sore throat, hoarseness of voice and cough

Background and Aims: Post-operative sore throat (POST) is often considered an inevitable consequence of tracheal intubation. This study was performed to compare the effect of inhaled budesonide suspension, administered using a metered dose inhaler, on the incidence and severity of POST. Methods: In this prospective randomised study, 46 patients undergoing laparoscopic surgeries lasting <2 h were randomly allotted into two equal groups. Group A received 200 μg budesonide inhalation suspension, using a metered dose inhaler, 10 min before intubation, and repeated 6 h after extubation. No such intervention was performed in Group B. The primary outcome was the incidence and severity of POST. Secondary outocomes included the incidence of post-operative hoarseness and cough. Pearsons Chi-square test, Fishers exact test and Independent sample t-test were used as applicable. Results: Compared to Group B, significantly fewer patients had POST in Group A at 2, 6, 12 and 24 h (P < 0.001). Although more patients in Group B had post-operative hoarseness of voice and cough at all-time points, the difference was statistically significant only at 12 h and 24 h for post-operative hoarseness and at 2 h and 12 h for post-operative cough. Severity as well as the incidence of POST showed downward trends in both groups over time, and by 24 h no patient in Group A had sore throat. Conclusion: Inhaled budesonide suspension is effective in significantly reducing the incidence and severity of POST.

Carbon dioxide embolism during endoscopic thyroidectomy

Sir, A 48-year-old American Society of Anesthesiologists physical status I patient, weighing 68 kg with diagnosis of bilateral thyroid nodules (4 cm × 5 cm) and euthyroid, was posted for endoscopic total thyroidectomy. General anaesthesia was induced and maintained following a standardised protocol. Intra-operatively, heart rate (HR) ranged from 70 to 90/min, systolic blood pressure (BP) 110–130 mmHg, and oxygen saturation (SpO2) 99–100%. Electrocardiogram showed normal sinus rhythm. Respiratory rate and tidal volume were adjusted to maintain end tidal carbon dioxide (EtCO2) between 30 and 35 mmHg. By the end of 3 h, dissection of gland was complete with good haemostasis. Suddenly, EtCO2 dropped from 34 to 8 mmHg, SpO2 to 60%, with hypotension (BP-80/50 mmHg) and bradycardia (HR-42/min). There were no disconnections or leaks in the circuit. Auscultation was not possible as the surgical ports were placed at axilla and areola of nipple bilaterally, but chest showed adequate and equal expansion. With a presumptive diagnosis of pulmonary embolism, surgery was stopped and sample for an arterial blood gas (ABG) was sent. The patient position was changed from head up to head down, but we were not able to give left lateral position as laparoscopic ports were still in situ. The diagnosis of pulmonary embolism was presumed with ABG showing pH of 7.081, PaCO2 84.5 mmHg, PaO2 61.2 mmHg and bicarbonate 24.0 mmol/L corresponding to an EtCO2 of 8 mmHg. After administration of glycopyrrolate 0.2 mg, ephedrine 6 mg and 100% O2, in 5 min the HR was 84/min, BP 130/86 mmHg, SpO2 98% and EtCO2 34 mmHg. An arterial line was introduced and ABG taken at this point showed pH 7.38, pCO2 33.8 mmHg, pO2 165 mmHg, bicarbonate 19.7 mmol/L. A re-evaluation of the equipment and settings showed CO2 inflation pressure erroneously set at 20 mmHg. As the only remaining surgical procedure was external removal of the already dissected gland, endoscopy was allowed again. The inflation pressure was reduced to 14 mmHg, positive end-expiratory pressure (PEEP) of 6 cm H2O was added and an intravenous fluid bolus of about 500 ml was administered. Surgery lasted for 30 min longer and was uneventful with a normal EtCO2 (32–34 mmHg), vitals and ABG (pH 7.313, pCO2 41.2 mmHg, pO2 229 mmHg, bicarbonate 20.3 mmol/L). At the end of surgery, patient was reversed of neuromuscular blockade and trachea extubated. Clinically significant carbon dioxide embolism is a rare but potentially fatal complication and may result from direct intravascular insufflation of CO2 during surgery.[1] During neck surgeries, many vessels need to be dissected and it is possible to miss a tear in a small vein as it may remain collapsed due to compression by gas under pressure in the cavity created by the inflated gas. If the intra-cavitary pressure is high, gas can be forced into circulation through the opening causing pulmonary embolism. Gas embolism should be suspected if there is a sudden drop in EtCO2[2,3] and is suggestive with hypercarbia and hypoxia. This indicates a failure of gas exchange due to reduction in alveolar perfusion. The sudden recovery following discontinuation of CO2 in our case could be explained by the high solubility of CO2. The blood gases with normal bicarbonate at the point of occurrence of the embolus could be explained by the fact that renal compensation may not have occurred at the time of the event. Although a transthoracic or trans-oesophageal echo could have confirmed the diagnosis,[4] the rapidity of events did not allow us to get the monitors. Aggressive volume expansion and PEEP reduce gas embolism by increasing venous pressure.[5,6] This incident stresses the chance of carbon dioxide pulmonary embolus during endoscopic surgeries. Although definitive confirmatory tests may be unavailable at the time of manifestation, continuous EtCO2 monitoring and vigilance may help in an early detection. Timed appropriate treatment may help in the management of this potentially catastrophic situation. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Respiratory and hemodynamic outcomes following exchange extubation with laryngeal mask airway as compared to traditional awake extubation.

Background: Traditional awake extubation leads to respiratory complications and hemodynamic response which are detrimental in neurosurgery, ENT surgery and patients with comorbidities. Aims: The primary objective was to compare the respiratory complications and hemodynamic stress response between traditional awake extubation of a endotracheal tube (ETT) and that following exchange extubation of ETT by using a laryngeal mask airway (LMA). Settings and Design: This prospective randomized study was conducted in a Tertiary Care Centre in 60 American Society of Anesthesiologists I and II patients coming for general surgery. Materials and Methods: Patients were randomized by permuted blocks into traditional awake extubation group and exchange extubation group. At the end of surgery in traditional group, awake extubation of ETT was done. In exchange group, 0.3 mg/kg propofol was administered, and the ETT was exchanged for a LMA. Awake extubation of LMA was then performed. Respiratory complications such as bucking, coughing, desaturation and the need for airway maneuvers and hemodynamic response were noted in both groups. Analysis Tools: Chi-square test, independent sample t- and paired t-tests were used as applicable. Results: Incidence of respiratory complication was 93.3% in traditional extubation while it was only 36.7% in exchange extubation group (P < 0.001). Hemodynamic response measured immediately at extubation in terms of heart rate, systolic blood pressure (BP), diastolic BP, mean arterial pressure, and rate pressure product were all significantly lesser in exchange group when compared to traditional extubation. Conclusion: Exchange extubation with LMA decreases respiratory complications and hemodynamic stress response when compared to traditional awake extubation.