Venkatesan Thiruvenkatarajan

Cranial nerve injuries with supraglottic airway devices: a systematic review of published case reports and series

Cranial nerve injuries are unusual complications of supraglottic airway use. Branches of the trigeminal, glossopharyngeal, vagus and the hypoglossal nerve may all be injured. We performed a systematic review of published case reports and case series of cranial nerve injury from the use of supraglottic airway devices. Lingual nerve injury was the most commonly reported (22 patients), followed by recurrent laryngeal (17 patients), hypoglossal (11 patients), glossopharyngeal (three patients), inferior alveolar (two patients) and infra‐orbital (one patient). Injury is generally thought to result from pressure neuropraxia. Contributing factors may include: an inappropriate size or misplacement of the device; patient position; overinflation of the device cuff; and poor technique. Injuries other than to the recurrent laryngeal nerve are usually mild and self‐limiting. Understanding the diverse presentation of cranial nerve injuries helps to distinguish them from other complications and assists in their management.

Coagulation testing in the perioperative period

Perioperative coagulation management is a complex task that has a significant impact on the perioperative journey of patients. Anaesthesia providers play a critical role in the decision-making on transfusion and/or haemostatic therapy in the surgical setting. Various tests are available in identifying coagulation abnormalities in the perioperative period. While the rapidly available bedside haemoglobin measurements can guide the transfusion of red blood cells, blood product administration is guided by many in vivo and in vitro tests. The introduction of newer anticoagulant medications and the implementation of the modified in vivo coagulation cascade have given a new dimension to the field of perioperative transfusion medicine. A proper understanding of the application and interpretation of the coagulation tests is vital for a good perioperative outcome.

Lingual nerve neuropraxia following use of the Laryngeal Mask Airway Supreme.

Cranial nerve injury is a rare complication with the use of supraglottic airway devices. A case of lingual nerve injury following the use of a Laryngeal Mask Airway Supreme in a 45 year old woman is presented. A review of the literature regarding lingual nerve injury as a complication of the supraglottic airway is also presented.

Erector spinae plane block as an alternative to epidural analgesia for post-operative analgesia following video-assisted thoracoscopic surgery: A case study and a literature review on the spread of local anaesthetic in the erector spinae plane

Post-operative pain after minimally invasive video-assisted thoracoscopic surgery (VATS) in adults is commonly managed with oral and parenteral opioids and invasive regional techniques such as thoracic epidural blockade. Emerging research has shown that the novel erector spinae plane (ESP) block, can be employed as a simple and safe alternative analgesic technique for acute post-surgical, post-traumatic and chronic neuropathic thoracic pain in adults. We illustrate this by presenting a paediatric case of VATS, in which an ESP block provided better analgesia, due to greater dermatomal coverage, as well as reduced side-effects when compared with a thoracic epidural that had previously been employed on the same patient for a similar procedure on the opposite side.

The effect of perioperative esmolol on early postoperative pain: A systematic review and meta-analysis

Esmolol has been shown to improve postoperative pain and reduce opioid requirements. The aim of this systematic review was to evaluate the effect of perioperative esmolol as an adjunct on early postoperative pain intensity, recovery profile, and anesthetic requirement. Databases were searched for randomized placebo-controlled trials evaluating the effects of esmolol during general anesthesia. Primary outcomes were related to early postoperative pain whereas secondary outcomes were related to emergence time, postoperative nausea and vomiting, and intraoperative anesthetic requirement. Nineteen trials were identified involving 936 patients (esmolol = 470, placebo = 466). In esmolol group, numeric pain scores at rest in the immediate postoperative period were reduced by 1.16 (95% confidence interval [CI]: 1.97–0.35, I2 = 96.7%) out of 10. Opioid consumption was also decreased in the postanesthesia care unit compared with placebo, mean difference of 5.1 mg (95% CI: 7.0–3.2, I2 = 96.9%) morphine IV equivalents; a 69% reduction in opioid rescue dosing was noted (odds ratio [OR]: 0.31, 95% CI: 0.16–0.80, I2 = 0.0%). A 61% reduction in postoperative nausea and vomiting was also evident (OR: 0.39, 95% CI: 0.20–0.75, I2 = 60.7%). A reduction in propofol induction dose was noted in the esmolol group (mean difference: −0.53 mg/kg, 95% CI: −0.63–−0.44, I2 = 0.0%). A decrease in end-tidal desflurane equivalent (mean difference: 1.70%, 95% CI: −2.39–−1.02, I2 = 92.0%) and intraoperative opioid usage (fentanyl equivalent, mean difference: 440 μg, 95% CI: −637–−244, I2 = 99.6%) was observed in esmolol group. Esmolol had no effect on the emergence time. Perioperative esmolol as an adjunct may reduce postoperative pain intensity, opioid consumption, and postoperative nausea vomiting. Given the heterogeneity, larger clinical trials are warranted to confirm these findings.

Risk of perioperative torsade de pointes in patients with poorly controlled diabetes mellitus.

To the Editor Turan et al.’s 1 discussion and accompanying editorial2 cogently discuss the limitations of their retrospective study design and are further complemented by the senior author’s recent manuscript demonstrating the importance of prospective validation of retrospective findings.3 Nevertheless, I would like to offer an important factual correction to the stated limitations that continues to go unrecognized in many studies of this type. Turan et al.1 state: “To the extent that outcomes occurred postoperatively or were missed through incomplete coding, reported frequencies will underestimate the true incidence. But unless outcome identification in our registry is biased (i.e., nonrandomly erroneous in patients given or not given N2O), reported odds ratios will remain accurate.”1 Alas, the idea that independent, random errors in the assessment of an outcome will not affect observed odds ratios of that outcome is likely not true. An imperfect marker of an outcome when used to compare an actual outcome between 2 sample populations will carry disparate positive and negative predictive values for the actual outcome that depend on the sensitivity and specificity of the imperfect marker and on the differences in the incidence of the true outcome between the 2 sample populations being compared. In the case of mortality, markers for this outcome are frequently quite accurate so that the observed odds ratio of the imperfect marker for mortality will likely be close to the corresponding odds ratio of actual mortality in the study samples. Although bias occurring as a result of random errors in ascertaining an outcome will certainly distort an observed odds ratio away from the actual odds ratio present between samples, the effect will only become large in cases where the odds ratio of actual outcome between samples departs dramatically from 1 and where the marker for the outcome is relatively inaccurate. More concerning in the present study, however, may be the distortional effect stemming from imperfect comorbidity coding in the face of baseline systematic differences in disease prevalence between healthier patients receiving nitrous oxide and sicker patients not receiving it. Because of the relationship among comorbidity prevalence and the positive and negative predictive values of comorbidity coding, purely random errors in ascertaining comorbidity status likely distorted the observed odds ratios away from 1. I do not know whether the resulting differences were of the magnitude to have changed the conclusions of the manuscript, but this is a question that could no doubt be well handled by this superb group of investigators. As a demonstration of the relevance of this issue, my colleagues and I have recently modeled the effects of misclassification bias on type 1 error when comparisons of a systematically sicker and healthier population are made using To the Editor Johnston et al. 1 have done commendable work analyzing the reported cases of torsade de pointes (TdP) and presenting some interesting findings. Among the acquired causes of QTc prolongation, coadministered medications have drawn the major attention so far. Apart from drugs and electrolyte imbalances, there are other comorbid conditions that can lead to acquired QTc prolongation and TdP. Uncontrolled diabetes mellitus in the operative setting is one such entity. Acute hyperglycemia as well as autonomic dysfunction in diabetic patients have been shown to increase the QTc interval, predisposing the patients to malignant arrhythmias.2,3 In diabetic patients, QTc interval prolongation has been proposed as an indicator of increased risk of sudden death.3 Blood sugar level is an independent predictor of QTc interval prolongation in critically ill patients.4 In addition, hypomagnesemia is widely prevalent in diabetic patients.5 We reported a case of TdP in a patient with poorly controlled diabetes during sevoflurane anesthesia.6 Hence, extra vigilance towards the QTc interval may be warranted in this patient population.

A manikin-based evaluation of a teaching modality for ultrasound-guided infraclavicular longitudinal in-plane axillary vein cannulation in comparison with ultrasound-guided internal jugular vein cannulation: A pilot study

Background and Aims: Ultrasound (US)-guided infraclavicular approach for axillary vein (AXV) cannulation has gained popularity in the last decade. Material and Methods: In this manikin study, we evaluated the feasibility of a training model for teaching AXV cannulation. The learning pattern with this technique was assessed among attending anesthesiologists and residents in training. Results: A faster learning pattern was observed for AXV cannulation among the attending anesthesiologists and residents in training, irrespective of their prior experience with US. It was evident that a training modality for this technique could be easily established with a phantom model and that hands-on training motivates trainees to embrace US-based central venous cannulation. Conclusion: A teaching model for US-guided infraclavicular longitudinal in-plane AXV cannulation can be established using a phantom model. A focused educational program would result in an appreciable change in preference in embracing US-based cannulation techniques among residents.

Hirnnervenschädigungen bei supraglottischen Atemwegshilfen

Schadigungen von Hirnnervenasten bei der Anwendung supraglottischer Atemwegshilfen betreffen v. a. Aste der Nn. trigeminus, glossopharyngeus, recurrens und hypoglossus. Die Inzidenz der Nervenschaden ist unklar, es existieren nur Einzelfallberichte bzw. Fallserien.