Prasanna Udupi Bidkar

Influence of Head and Neck Position on Oropharyngeal Leak Pressure and Cuff Position with the ProSeal Laryngeal Mask Airway and the I-Gel: A Randomized Clinical Trial.

Background. This study was designed to assess and compare the effect of head and neck position on the oropharyngeal leak pressures and cuff position (employing fibreoptic view of the glottis) and ventilation scores between ProSeal LMA and the I-gel. Material and Methods. After induction of anesthesia, the supraglottic device was inserted and ventilation confirmed. The position of the head was randomly changed from neutral to flexion, extension, and lateral rotation (left). The oropharyngeal leak pressures, fibreoptic view of glottis, ventilation scores, and delivered tidal volumes and end tidal CO2 were noted in all positions. Results. In both groups compared with neutral position, oropharyngeal leak pressures were significantly higher with flexion and lower with extension but similar with rotation of head and neck. However the oropharyngeal leak pressure was significantly higher for ProSeal LMA compared with the I-gel in all positions. Peak airway pressures were significantly higher with flexion in both groups (however this did not affect ventilation), lower with extension in ProSeal group, and comparable in I-gel group but did not change significantly with rotation of head and neck in both groups. Conclusion. Effective ventilation can be done with both ProSeal LMA and I-gel with head in all the above positions. ProSeal LMA has a better margin of safety than I-gel due to better sealing pressures except in flexion where the increase in airway pressure is more with the former. Extreme precaution should be taken in flexion position in ProSeal LMA.

PERIPHERAL NERVE INJURIES.

Various positions are used in neurosurgery, including supine, lateral, prone, and sitting as well as many modifications of these positions. If the positioning is not done properly, position-related nerve injuries can occur more commonly than in other surgeries as majority of surgeries are of longer duration in neurosurgery. The etiopathogenesis, causes, and signs and symptoms are discussed. The treatment and preventive options are also discussed in this chapter.Various positions are used in neurosurgery, including supine, lateral, prone, and sitting as well as many modifications of these positions. If the positioning is not done properly, position-related nerve injuries can occur more commonly than in other surgeries as majority of surgeries are of longer duration in neurosurgery. The etiopathogenesis, causes, and signs and symptoms are discussed. The treatment and preventive options are also discussed in this chapter.

Diagnostic accuracy of bedside tests for predicting difficult intubation in Indian population: An observational study.

Background: Unanticipated difficult intubation can be challenging to anesthesiologists, and various bedside tests have been tried to predict difficult intubation. Aims: The aim of this study was to determine the incidence of difficult intubation in the Indian population and also to determine the diagnostic accuracy of bedside tests in predicting difficult intubation. Settings and Design: In this study, 200 patients belonging to age group 18–60 years of American Society of Anesthesiologists I and II, scheduled for surgery under general anesthesia requiring endotracheal intubation were enrolled. Patients with upper airway pathology, neck mass, and cervical spine injury were excluded from the study. Materials and Methods: An attending anesthesiologist conducted preoperative assessment and recorded parameters such as body mass index, modified Mallampati grading, inter-incisor distance, neck circumference, and thyromental distance (NC/TMD). After standard anesthetic induction, laryngoscopy was performed, and intubation difficulty assessed using intubation difficulty scale on the basis of seven variables. Statistical Analysis: The Chi-square test or student t-test was performed when appropriate. The binary multivariate logistic regression (forward-Wald) model was used to determine the independent risk factors. Results: Among the 200 patients, 26 patients had difficult intubation with an incidence of 13%. Among different variables, the Mallampati score and NC/TMD were independently associated with difficult intubation. Receiver operating characteristic curve showed a cut-off point of 3 or 4 for Mallampati score and 5.62 for NC/TMD to predict difficult intubation. Conclusion: The diagnostic accuracy of NC/TM ratio and Mallampatti score were better compared to other bedside tests to predict difficult intubation in Indian population.

Comparison of dexmedetomidine with fentanyl for maintenance of intraoperative hemodynamics in hypertensive patients undergoing major surgery: A randomized controlled trial

Background: The objective of this study was to study and compare the effects of intravenous dexmedetomidine and fentanyl on intraoperative hemodynamics, opioid consumption, and recovery characteristics in hypertensive patients. Methods: Fifty-seven hypertensive patients undergoing major surgery were randomized into two groups, Group D (dexmedetomidine, n = 29) and Group F (fentanyl, n = 28). The patients received 1 μg/kg of either dexmedetomidine or fentanyl, followed by 0.5 μg/kg/h infusion of the same drug, followed by a standard induction protocol. Heart rate (HR), mean arterial pressures (MAPs), end-tidal isoflurane concentration, and use of additional fentanyl and vasopressors were recorded throughout. Results: Both dexmedetomidine and fentanyl caused significant fall in HR and MAP after induction and dexmedetomidine significantly reduced the induction dose of thiopentone (P = 0.026). After laryngoscopy and intubation, patients in Group D experienced a fall in HR and a small rise in MAP (P = 0.094) while those in Group F showed significant rise in HR (P = 0.01) and MAP (P = 0.004). The requirement of isoflurane and fentanyl boluses was significantly less in Group D. The duration of postoperative analgesia was longer in Group D (P = 0.015) with significantly lower postoperative nausea and vomiting (PONV) (P < 0.001). Conclusion: Infusion of dexmedetomidine in hypertensive patients controlled the sympathetic stress response better than fentanyl and provided stable intraoperative hemodynamics. It reduced the dose of thiopentone, requirement of isoflurane and fentanyl boluses. The postoperative analgesia was prolonged, and incidence of PONV was less in patients who received dexmedetomidine.

Postoperative analgesia after inguinal hernia repair - Comparison of ropivacaine with bupivacaine: A randomized controlled trial.

Background: Postoperative pain management by surgical site infiltration has an edge over other methods of analgesia as it is simple and has lesser side effects. This study was designed to compare the analgesic effects provided by bupivacaine, a classical long-acting local anesthetic and ropivacaine, a new amino amide local anesthetic agent. Subjects and Methods: Ninety patients scheduled for elective inguinal herniorrhaphy were randomly allocated to one of the three groups: Group I - R 0.5, group II - R 0.25, and group III - B 0.25. General anesthesia was given. The surgical site was infiltrated before incision with 20 ml of drugs - ropivacaine 0.5% in group I, ropivacaine 0.25% in group II, bupivacaine 0.25% in group III. Intraoperatively hemodynamics were recorded every 15 min until the end of surgery and at the time of skin incision, at the time of cord pulling, and at the time of skin closure. Postoperatively, rest pain, pain on coughing, and pain on movements were assessed using visual analog scale (VAS) score immediately at the end of the surgery and hourly up to 4 h. The time of the first request for rescue analgesia was noted. Results: VAS scores at rest, during coughing and movements were higher in group R 0.25 and the time of rescue analgesia was shorter with group R 0.25 when compared with other groups. Conclusion: Ropivacaine is less potent than bupivacaine at equal concentrations.

Tuberculoma of the Cavernous Sinus and Meckel's Cave in a Child.

Tuberculous infection of the cavernous sinus and Meckels cave is extremely rare. In this report, we describe a patient with tuberculoma of the cavernous sinus and Meckels cave, extending to the petrous apex. The patient underwent microsurgical excision of the lesion and antitubercular chemotherapy resulting in a good outcome. We describe the diagnostic difficulties and review the relevant literature.

Evaluation of simple pre-determined length insertion technique (SPLIT) with conventional method for oral fibreoptic intubation: A randomised cross-over study

Background and Aims: The difficulty during flexible fiber-optic bronchoscopy (FOB) guided tracheal intubation could be because of inability in visualising glottis, advancing and railroading of endotracheal tube. Several methods are available for visualising glottis, but none is ideal. Hence, this randomised controlled study was designed to evaluate the simple pre-determined length insertion technique (SPLIT) during oral FOB. Methods: Fifty-eight patients were randomised into Group C and Group P. General anaesthesia was maintained with sevoflurane and oxygen in spontaneous respiration. In Group C, conventional flexible fiberoptic laryngoscopy was done followed by SPLIT and vice versa in Group P. The time to visualise the glottis (T1), from glottic visualisation to pass beyond glottis (T2) and from incisors to pass beyond the glottis (T3) were noted from the recorded video. The time interval was analysed using Wilcoxon matched pairs test and Mann–Whitney U-test. Results: The T1was significantly less in SPLIT as compared to conventional technique (13 [10, 20.25] vs. 33 [22, 48] s). The T3was significantly less in SPLIT (24.5 [19.75, 30] vs. 44 [34, 61.25] s). The T1by SPLIT was comparable between residents and consultants (P = 0.09), whereas it was significantly more among residents than the conventional technique. The SPLIT was preferred by 91.3% anaesthesiologists. Conclusion: The SPLIT significantly lessened the time to visualise the glottis than conventional technique for FOB. The SPLIT was the preferred technique. Hence, we suggest using the SPLIT to secure the airway at the earliest and also as an alternative to conventional technique.

Chapter 45 – Neuromuscular Disorders

The term neuromuscular disorder encompasses a heterogeneous group of disorders affecting skeletal muscles due to abnormalities in nerve, neuromuscular junction, or ion channels or due to metabolic derangements. Management of these patients is a challenge in the perioperative period and also in neuro–intensive care units. Various neurological disorders and medications may influence the preoperative evaluation, conduct of anesthesia, and postoperative management of these patients. Myasthenia gravis and Guillain–Barre syndrome are the two most frequently encountered neurologic disorders by neuroanesthesiologists and neurointensivists in their clinical practice. These patients may be on multiple medications for the primary neurologic disorder, which may influence the use of anesthetic medications. Also, it is challenging to provide perioperative care for deep brain stimulation for patients with Parkinson’s disease, when they are scheduled for awake craniotomy for stimulator lead placement. In this chapter, the authors discuss some of the important neurologic disorders and their anesthetic management.

A modified insertion technique of ambu AuraGain™ laryngeal airway, a third-generation supraglottic airway to reduce the oral mucosal injury

Sir, Ambu AuraGainTM[1] is a new single-use supraglottic airway (SGA) device available in adult size 3, 4, and 5. It is an anatomically curved SGA with integrated gastric access and can be used as a conduit for direct endotracheal intubation assisted by a flexible scope.[1] The standard recommended insertion technique is as that of intubating laryngeal mask airway (LMA),[2] i.e., keeping the handle (Shaft) approximately parallel to the patient’s chest and then pushing the device along the hard palate after opening the mouth [Figure 1a]. With the previous experience of other faculty and residents with this device in our institute, we noticed that a higher tangential force is required for the placement due to bulky and acute angle of the device. Due to difficulty in insertion, few cases also resulted in oral mucosal injury in the form of bleeding and ulceration with inadequate sealing and higher airway pressure.

Comparison of different regimens of intravenous dexmedetomidine on duration of subarachnoid block

Background and Aims: Many studies have studied the effect of intravenous dexmedetomidine on the prolongation of the duration of the subarachnoid block (SAB). These studies had administered dexmedetomidine using different regimens. This study was designed to find out the suitable regimen with maximum advantages and minimum disadvantages. Material and Methods: Ninety-three ASA 1 and 2 patients scheduled to undergo surgeries under SAB were randomly allocated into three groups namely B, M, and BM. After SAB, Group B received 0.5 μg/kg of dexmedetomidine bolus over 15 min, Group M received 0.5 μg/kg/h of dexmedetomidine infusion until the end of surgery, Group BM received both bolus and infusion. Results: The time to achieve T10 sensory level (SL) was significantly faster in the Groups B and BM than in the Group M. Maximum block height achieved was T4 and was same in all the groups. The Time to achieve maximum SL and Bromage 3 was comparable in all groups. The two-segment regression time and time to reach Bromage 0 was significantly higher in Groups M and BM than Group B. The time for a first request of analgesia was similar in Groups M and BM. The maximum sedation attained in all groups was Ramsay Sedation Score of 3. Side effects such as bradycardia, hypotension, and desaturation were comparable between the groups. Conclusion: We conclude that the continuous infusion of dexmedetomidine results in more advantages than just a bolus dose. Therefore, we suggest using only the maintenance dose of intravenous dexmedetomidine after subarachnoid blockade for prolonging the duration and achieving sedation.