Anaesthesia

The subcostal nerve as the target for nerve stimulator–guided transversus abdominis plane blocks - Commentary Sumitra G Bakshi Indian Journal of Anaesthesia 2019 63(4):255-256

Radiological evaluation of airway – What an anaesthesiologist needs to know! Kinshuki Jain, Nishkarsh Gupta, Mukesh Yadav, Sanjay Thulkar, Sushma Bhatnagar Indian Journal of Anaesthesia 2019 63(4):257-264 Airway management forms the foundation of any anaesthetic management. However, unanticipated difficult airway (DA) and its sequelae continue to dread any anaesthesiologist. In spite of development of various clinical parameters to judge DA, no single parameter has proved to be accurate in predicting it. Radiological evaluation may help assess the aspects of patient's airway not visualised through the naked eye. Starting from traditional roentgenogram to ultramodern three-dimensional printing, imaging may assist the anaesthesiologists in predicting DA and formulate plan for its management. Right from predicting DA, it has been used for estimating endotracheal tube sizes, assessing airway pathologies in paediatric patients and planning extubation strategies. This article attempts to provide exhaustive overview on radiological parameters which can be utilised by anaesthesiologists for prediction of DA.

The subcostal nerve as the target for nerve stimulator guided transverse abdominis plane blocks – A feasibility study Prasanna Vadhanan, Mohammed Hussain, Revathy Prakash Indian Journal of Anaesthesia 2019 63(4):265-269 Background and Aims: Transverse Abdominis Plane (TAP) block was originally described as a landmark-based technique. Peripheral nerve stimulator (PNS) guided blocks are still widely performed, where ultrasound is unavailable. Methods: Cadaveric dissections were performed which showed the subcostal nerve following a predictable course at the lateral abdominal wall in the TAP. The subcostal nerve was identified by ultrasound in three volunteers. Stimulation of the subcostal nerve was performed using PNS and landmarks as guidance in and 20 patients. Twitches of the anterior abdominal wall muscles were elicited, and needle position and drug dispersion were confirmed using ultrasound. Results: Out of 32 attempts made, the drug dispersion was appropriate in 24, not appropriate on four insertions and twitches were not elicited in 4 attempts. Conclusion: Nerve stimulator can be used as a guidance for TAP blocks where the availability of ultrasound is limited.

Reliability of the thyromental height test for prediction of difficult visualisation of the larynx: A prospective external validation Shizuha Yabuki, Satoka Iwaoka, Mamoru Murakami, Hiroko Miura Indian Journal of Anaesthesia 2019 63(4):270-276 Background and Aims: Thyromental height (TMH) has been reported to be useful for prediction of difficult visualisation of the larynx (DVL), defined as Cormack--Lehane (C&L) grade III or IV. The aim of this study was to compare the diagnostic accuracy of the TMH test for DVL with that of other clinically used tests in Japanese patients. Methods: Six hundred and nine surgical patients undergoing endotracheal intubation under general anaesthesia were enrolled in this prospective observational study. TMH, thyromental distance (TMD), and Samsoon and Young's modified Mallampati (MMT) tests were performed in all patients. The C&L grades for the laryngoscopic view with and without external backward, upward, rightward pressure (BURP) were determined by designated airway assessors. The cutoff value for the TMH test was calculated using receiver-operating characteristic (ROC) curve analysis. The sensitivity, specificity, positive predictive value, accuracy, positive likelihood ratio, and area under the ROC curve (AUROC) for each predictive test were calculated and compared. Results: ROC curve analysis indicated that 54 mm is the optimal cutoff value for the TMH test. However, both this value and the conventional cutoff value of 50 mm, which has been reported as having good diagnostic accuracy in the literature, had poor diagnostic accuracy. The AUROC for the TMH test was 0.631 without BURP and 0.592 with BURP; these values were not superior to those for the TMD test or MMT. Conclusion: The TMH test is not a good predictor of DVL in Japanese patients.

Correlation between bispectral index, end-tidal anaesthetic gas concentration and difference in inspired–end-tidal oxygen concentration as measures of anaesthetic depth in paediatric patients posted for short surgical procedures Raylene Dias, Nandini Dave, Barkha Agrawal, Aarti Baghele Indian Journal of Anaesthesia 2019 63(4):277-283 Background and Aims: Measurement of end-tidal anaesthetic gas concentrations (ETAG) is currently a pragmatic indicator for monitoring anaesthetic depth. We aimed to assess the performance of ETAG for sevoflurane (ETAG-sevo) with bispectral index (BIS) and difference between inspired and end-tidal oxygen concentration (Fi−Et)O2% in measuring anaesthetic depth in toddlers and preschool children. Primary outcome was to correlate BIS with ETAG-sevo. Secondary outcome was to correlate (Fi−Et)O2% with ETAG-sevo and to derive cut-off value of (Fi−Et)O2%which corresponds with light planes of anaesthesia [minimum alveolar concentration (MAC <0.6)]. Methods: Thirty patients between 1 and 5 years of age undergoing short procedures were included. ETAG, MAC, BIS and (Fi−Et)O2% were measured at intubation, maintenance phase, last 15 min of surgery, end of surgery, extubation, recovery. Pearson's correlation coefficient was used to measure correlation. Receiver operating characteristic (ROC) curves were used to derive cut-off value of (Fi−Et)O2% which corresponded with MAC <0.6. Results: BIS correlated poorly with ETAG at all time intervals. Significant correlation was seen between (Fi−Et)O2% and ETAG at intubation (P = 0.042), last 15 min of surgery (P = 0.019) and end of surgery (P = 0.001). Cut-off value >7 was obtained for (Fi−Et)O2% corresponding to MAC <0.6 at extubation with area under ROC curve0.955 (95% confidence interval 0.811–0.997), with sensitivity 0.8571 and specificity 1.00. Conclusion: BIS was an unreliable measure of anaesthetic depth. (Fi−Et)O2% values >7 corresponded with light planes of anaesthesia.

Evaluation of performance of C-MAC® video laryngoscope Miller blade size zero for endotracheal intubation in preterm and ex-preterm infants: A retrospective analysis Renu Sinha, Kanil Ranjith Kumar, Ram Kumar Kalaiyarasan, Puneet Khanna, Bikash Ranjan Ray, Ravinder Kumar Pandey, Jyotsna Punj, Vanlal Darlong Indian Journal of Anaesthesia 2019 63(4):284-288 Background and Aims: The preterm and ex-preterm babies form a separate group among the paediatric population with unique airway anatomy. The utility of C-MAC® Video laryngoscope (VL) for routine intubation of preterm babies has not been evaluated. The purpose of this study is to report the performance of C-MAC® VL Miller blade size-0 for endotracheal intubation in preterm babies at our institute. Methods: After Institute Ethics Committee approval, a retrospective study was designed to evaluate the performance of C-MAC® VL for intubation in preterm and ex-preterm babies. The medical files, and video recordings of preterm babies up to 60 weeks of post-gestational age who had undergone surgery for retinopathy of prematurity from January 2014 to April 2016 were reviewed. All babies were intubated with C-MAC® Miller blade size-0. Demographic parameters, time to best glottic view (TTGV), time to intubate (TTI), ease and number of intubation attempts were assessed. Episodes of desaturation and complications related to intubation were recorded. Results: Data of 37 preterm and ex-preterm babies were analysed. The mean age and weight at the time of surgery were 40.5 (±4.9) weeks and 2532 (±879) grams respectively. The median TTGV and TTI were 11.0 and 22.0 seconds. A total of 32 babies (86.5%) were intubated on initial attempt and five were intubated on second attempt. Stylet was used to facilitate intubation in all infants. There was no incidence of desaturation, mucosal injury or bleeding. Conclusion: C-MAC video laryngoscope Miller blade size 0 is suitable for endotracheal intubation in preterm and ex-preterm infants.

Comparing the efficacy of aprepitant and ondansetron for the prevention of postoperative nausea and vomiting (PONV): A double blinded, randomised control trial in patients undergoing breast and thyroid surgeries Salome Jeyabalan, Suma Mary Thampi, Reka Karuppusami, Kunder Samuel Indian Journal of Anaesthesia 2019 63(4):289-294 Background and Aims: Aprepitant, a Neurokinin-1 receptor antagonist, has been evaluated in abdominal and neurosurgeries, but its effect is less clear in breast and thyroid surgeries, which are also known to be high risk for post-operative nausea and vomiting (PONV). This study was done to compare the antiemetic efficacy of ondansetron and aprepitant in women undergoing mastectomy and thyroidectomy. Methods: One hundred and twenty-five ASA I and II, female patients, aged between 18 and 65 years were randomly assigned into Group I (ondansetron group, n = 62) or Group II (aprepitant group, n = 63), by computer-generated random sequencing. Per protocol analysis was done to assess the incidence and severity of PONV, use of rescue antiemetics, and patient satisfaction with PONV control between the two groups, till 24 h post-surgery. Results: In the immediate postoperative period, 79.7% of patients in Group I and 85.2% in Group II were free of emesis (P value: 0.49). In Group I, the first episode of vomiting occurred within a median duration 90 min (IQR 2575: 45-147) postoperatively, whereas the median duration in Group II was 160 min (IQR 25-75: 26-490), with request for rescue antiemetic at 60 min in Group I (IQR 25-75: 27-360) and 147 min in Group II (IQR 25-75: 11-457). Conclusion: A single dose of oral aprepitant has comparable effects to injection ondansetron administered eighth hourly in preventing PONV, the severity of nausea, number of rescue antiemetics, and the time to first emetic episode in the 24-h postoperative period. CTRI Reg No: REF/2017/06/014637.

Comparison of Full Outline of UnResponsiveness (FOUR) score and the conventional scores in predicting outcome in aneurysmal subarachnoid haemorrhage patients Rajeeb Kumar Mishra, Charu Mahajan, Indu Kapoor, Hemanshu Prabhakar, Parmod Kumar Bithal Indian Journal of Anaesthesia 2019 63(4):295-299 Background and Aims: Full Outline of UnResponsiveness (FOUR) score is a more comprehensive score used to assess eye response, motor response, brainstem reflexes, and respiration that was introduced to overcome the drawbacks of Glasgow coma scale (GCS) score. Our aim was to assess which score best predicts mortality and poor outcome in aneurysmal subarachnoid haemorrhage (aSAH) patients. Methods: This cohort study, prospectively evaluated the use of FOUR score to assess the mortality and outcome in aSAH patients during the period from November 2015 to November 2016. For each patient of aSAH, GCS, FOUR score, Hunt and Hess (HH) score and World Federation of Neurological Surgeons (WFNS) score were determined at the time of admission to neurosurgical intensive care unit. All patients were followed till 28 days post-SAH and their outcome were assessed by Glasgow outcome scale (GOS). We calculated the sensitivity (Sn) and specificity (Sp) for each of these scores. We generated the receiver operating characteristic curve (ROC), quantified the accuracy by the area under curve (AUC), and also calculated their 95% confidence interval (95% CI). Results: A total of 75 aSAH patients were enrolled for the study. The mortality was 24/75 (32%) with 23 in-hospital deaths. FOUR score was highly specific (86.27%) and sensitive (75%) for the prediction of mortality. However, for predicting 28-day outcome, WFNS and HH grade were most specific (92.5%), whereas FOUR and HH score was moderately specific (68.57%). Conclusion: FOUR score is among the most specific and moderately sensitive tool for prediction of mortality. However, WFNS and HH grade are more specific in predicting the 28-day outcome.

Assessment of predisposing factors in myofascial pain syndrome and the analgesic effect of trigger point injections - A primary therapeutic interventional clinical trial S Parthasarathy, Siyam Sundar, Gayatri Mishra Indian Journal of Anaesthesia 2019 63(4):300-303 Background and Aims: Myofascial pain syndrome (MPS) is a common cause of chronic musculoskeletal pain, characterised by myofascial trigger points (TPs). TP injection is an established technique for management of MPS. In this study, we analysed the efficacy of myofascial TP injection of lignocaine and the influencing biomechanical factors on MPS. Methods: After obtaining ethical committee approval, we included the first 100 adult patients of MPS with failed physical therapy aged above 18 years, and with TPs in the trapezius, infraspinatus, and/or the levator scapulae muscles and Visual analog scale (VAS) >4. TP injection of 2% (2 ml) lignocaine was performed. Visual analogue scale (VAS) scores were recorded immediately and after 1 month. Number of repeat TP injections and use of oral analgesic in one month was noted. Results were analysed with the analysis of variance test. Results: The mean VAS reduced significantly both immediately and 1 month after therapeutic injections (8.57 ± 0.77, 2.67 ± 1.43 and 2.82 ± 1.4, respectively, P < 0.01). Keeping the palm below the head during sleep was the major contributing factor for myofascial TP, followed by slanting the neck to use mobile phones. Repeat TP injection was used in 4% of cases. Conclusion: TP injection of 2 ml of 2% lignocaine along with correction of predisposing biomechanical factors provided significant pain relief for MPS in patients with failed physical therapy without any side effects.

Magnesium sulphate optimises surgical field without attenuation of the stapaedius reflex in paediatric cochlear implant surgery Wahba Z Bakhet, Hassan A Wahba, Lobna M El Fiky, Hossam Debis Indian Journal of Anaesthesia 2019 63(4):304-309 Background and Aims: The anaesthesia technique for paediatric cochlear implantation should be modified to achieve an optimised surgical field and allow neuromonitoring. Total intravenous anaesthesia (TIVA) provides good surgical condition without affecting intraoperative electrical stapaedial reflex threshold (ESRT). Though magnesium sulphate (MgSO4) is a cheap, readily available drug for controlled hypotension, it can decrease the amplitude of motor-evoked potentials. This study aimed to evaluate the effect of MgSO4 infusion on quality of surgical field, intraoperative ESRT, and anaesthetic requirements in paediatric cochlear implant surgery performed under TIVA. Methods: In this randomised controlled trial, 66 children (1-6 years) undergoing cochlear implant under TIVA were randomly assigned to control group or MgSO4 group. The primary outcome was quality of surgical field, and the secondary outcomes were mean arterial blood pressure (MAP), heart rate (HR), ESRT, and the intraoperative anaesthetic requirements. The incidence of adverse events was recorded as well. Results: The quality of surgical field was better in group M than group C, P < 0.02. The number of children who achieved optimum surgical conditions (scores ≤2) was significantly better in the group M (n = 23/33, 70%) compared with group C (n = 13/33, 39%), P < 0.001. MAP, HR, and anaesthetic requirements were significantly lower in group M, P < 0.05. There were no differences between both groups regarding ESRT response. Conclusion: Magnesium sulphate IV infusion optimised surgical field and decreased anaesthetic requirements without attenuating the ESRT in paediatric cochlear implant surgery performed under TIVA.