Post-operative acute kidney injury (AKI) is a common complication of surgery with significant short- and long-term adverse consequences. The adoption of diagnostic criteria for AKI (RIFLE, AKIN and KDIGO) has facilitated comparison of data reported by different centres, confirming that even mild AKI is associated with excess mortality. It remains unclear whether this is caused by the kidney injury itself or whether AKI is simply a marker of underlying disease severity. There is no trial evidence to support the use of any specific therapeutic intervention in post-operative AKI. Best current treatment is, therefore, preventative by optimizing hydration and avoidance of nephrotoxins, emphasizing the importance of earlier detection and identification of individuals at high risk for AKI. In this review, we examine the latest literature on the management of post-operative AKI in adult patients, specifically the diagnosis and definition of AKI, epidemiology and pathogenesis and risk stratification in cardiac and non-cardiac surgery. We also review the latest evidence on pharmacological and non-pharmacological interventions.

We commend the authors for the recently published update of the AAGBI monitoring guidelines 1, and the continued drive to enhance the safety and quality of anaesthesia delivery. The guidance states “a measure of neuromuscular blockade, using a peripheral nerve stimulator, is essential for all stages of anaesthesia when neuromuscular blocking drugs are administered. This is best monitored using an objective, quantitative peripheral nerve stimulator. Ideally the adductor pollicis muscle response to ulnar nerve stimulation at the wrist should be monitored. Where this is not possible, the facial or posterior tibial nerves may be monitored”. While the facial nerve may be monitored, we feel it is important to highlight the potential pitfalls of this site, and that it is not as reliable as ulnar or posterior tibial nerve monitoring. The two muscles innervated by the facial nerve that are suited for neuromuscular monitoring are the orbicularis occuli (eyelid closing) and the corrugator supercilii (draws medial end of eyebrow downwards). However, due to the proximity of the neural plexus, the risk of direct muscle stimulation rather than nerve stimulation is very high, potentially leading to false interpretation. Additionally, it is well recognised that the twitch response of the orbicularis occuli recovers quicker than the adductor pollicis. The clinical relevance of this is highlighted in a study by Thilen et al. which showed that patients who had monitoring of eye muscles had a significantly greater incidence of residual paralysis than those monitored at the adductor pollicis 2. Indeed, the paper by Hemmerling et al. highlighted in the guidelines to support the statement for the interchangeable site of monitoring actually states “more peripheral muscles (e.g. adductor pollicis) need to be monitored in order to determine timely recovery of neuromuscular block” 3. We agree that the use of a quantitative peripheral nerve stimulator is the gold standard and what we should all strive to have routine access to this over the coming years 4. However, this is currently not the case. Therefore, we have concerns that mandating the use of a nerve stimulator, while highlighting the facial nerve as an alternative site of monitoring and without the above caveats, could lead to incidents of postoperative residual curarisation. This is likely to be confounded when anaesthetists unfamiliar with this site feel compelled to use it, but assume it can be managed in the same way as ulnar nerve monitoring.

We read with interest the concerns raised about the bougie hold-up sign causing airway trauma 1. The use of this sign in determining the position of the bougie is superior to tracheal ‘clicks’ alone, as shown by Kidd and colleagues 2. In the article by Paul and colleagues 3, the novel use of a traffic light depth gauge actively discourages the use of hold-up as an endpoint, relying solely on clicks. If we are to avoid the hold-up sign, then the accuracy of bougie positioning may be reduced, and perhaps it is time to look for another way of confirming bougie position. The use of capnography, as described by Millar and colleagues 4, may offer such confirmation.

BACKGROUND AND AIM:This study assessed the accuracy of using capnography with a modified, hollow gum elastic bougie in predicting tracheal intubation, and its effectiveness as a method of apnoeic oxygenation.METHODS:Patients were randomly allocated to having the gum elastic bougie inserted, under anaesthesia, in the trachea or the oesophagus. End-tidal carbon dioxide measurements were made at 10 and 20 s. The position of the gum elastic bougie was correctly predicted in 89.2% of patients. We tested the apnoeic oxygenation on an anaesthetic simulator model, which is housed in the Scottish Anaesthesia Simulator Centre, Stirling, UK.RESULTS:The time taken for the oxygen saturation to fall to 90% was significantly prolonged when the gum elastic bougie was used for apnoeic oxygenation.CONCLUSION:The modification of the gum elastic bougie allows a more objective assessment of correct placement than the previous tactile method. The current design of bougie is unsuitable but can be modified.

AnaesthesiaVolume 50, Issue 3 p. 270-270 Free Access Differential lung ventilation using a partial occlusion technique G.L. Hutchison, G.L. Hutchison Ninewells Hospital, Dundee DD1 9SYSearch for more papers by this authorF.A. Millar, F.A. Millar Ninewells Hospital, Dundee DD1 9SYSearch for more papers by this author G.L. Hutchison, G.L. Hutchison Ninewells Hospital, Dundee DD1 9SYSearch for more papers by this authorF.A. Millar, F.A. Millar Ninewells Hospital, Dundee DD1 9SYSearch for more papers by this author First published: March 1995 https://doi.org/10.1111/j.1365-2044.1995.tb04594.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. References [1] Millar FA, Hutchison GL, Wood RAB. Anaesthesia for thoracoscopic pleurectomy and ligation of bullae. Anaesthesia 1992; 47: 1060– 2. Volume50, Issue3March 1995Pages 270-270 ReferencesRelatedInformation

A patient is described who, despite severe pre-operative respiratory disability, had her persistent pneumothorax successfully managed by thoracoscopic pleurectomy. The technique causes considerably less pain and interference with respiratory function postoperatively than does conventional thoracotomy. Potential anaesthetic problems arise because of the necessity of insufflating carbon dioxide at pressures of up to 1 kPa to maintain a pneumothorax during surgery.

It was interesting to read the report by Serpell and colleagues on lumbar plexus block after total knee replacement (Anaesthesia 1991; 4 6 275-7) and I would like to comment on their conclusion. As in our preliminary study (with the block performed before surgery),’ Serpell demonstrated that patients with the lumbar plexus block required a third less morphine than the control group, but postoperative pain scores and the incidence of side effects were comparable. However, it is debatable whether a 35% reduction of total 48 hour consumption of morphine justifies the use of an invasive procedure (although safe and simple), when no other advantages such as a reduction in pain or side effects seem to be accomplished. The use of noninvasive procedures such as fixed NSAID regimens have been demonstrated to be even more effective, with a reduction in opioid requirements of up to 50% following major orthopaedic surgery,2 and in some studies with fewer side effects as well.3 It is my opinion that the introduction of an invasive method for postoperative pain relief is justified only by a substantial reduction in pain, opioid requirement or morbidity, and this does not seem to be accomplished with lumbar plexus block in knee arthroplasty .

A randomised controlled study was undertaken to assess the analgesic efficacy of continuous lumbar plexus block for the first 48 hours after total knee replacement surgery. Boluses of 0.5% bupivacaine with adrenaline 1 in 200,000 (0.3 ml/kg) were administered through a cannula inserted into the neurovascular sheath of the femoral nerve. Thirteen patients who received this block required significantly less morphine than a control group of 16 patients. Pain scores were similar and there were no complications related to this technique.