Protective intraoperative ventilation with higher versus lower levels of positive end-expiratory pressure in obese patients (PROBESE): study protocol for a randomized controlled trial

Background: Postoperative pulmonary complications (PPCs) increase the morbidity and mortality of surgery in obese patients. High levels of positive end-expiratory pressure (PEEP) with lung recruitment maneuvers may improve intraoperative respiratory function, but they can also compromise hemodynamics, and the effects on PPCs are uncertain. We hypothesized that intraoperative mechanical ventilation using high PEEP with periodic recruitment maneuvers, as compared with low PEEP without recruitment maneuvers, prevents PPCs in obese patients. Methods/design The PRotective Ventilation with Higher versus Lower PEEP during General Anesthesia for Surgery in OBESE Patients (PROBESE) study is a multicenter, two-arm, international randomized controlled trial. In total, 2013 obese patients with body mass index ≥35 kg/m2 scheduled for at least 2 h of surgery under general anesthesia and at intermediate to high risk for PPCs will be included. Patients are ventilated intraoperatively with a low tidal volume of 7 ml/kg (predicted body weight) and randomly assigned to PEEP of 12 cmH2O with lung recruitment maneuvers (high PEEP) or PEEP of 4 cmH2O without recruitment maneuvers (low PEEP). The occurrence of PPCs will be recorded as collapsed composite of single adverse pulmonary events and represents the primary endpoint. Discussion To our knowledge, the PROBESE trial is the first multicenter, international randomized controlled trial to compare the effects of two different levels of intraoperative PEEP during protective low tidal volume ventilation on PPCs in obese patients. The results of the PROBESE trial will support anesthesiologists in their decision to choose a certain PEEP level during general anesthesia for surgery in obese patients in an attempt to prevent PPCs. Trial registration ClinicalTrials.gov identifier: NCT02148692. Registered on 23 May 2014; last updated 7 June 2016. Electronic supplementary material The online version of this article (doi:10.1186/s13063-017-1929-0) contains supplementary material, which is available to authorized users

Preparing for the unexpected: special considerations and complications after sugammadex administration

Abstract Sugammadex, a modified gamma-cyclodextrin, has changed clinical practice of neuromuscular reversal dramatically. With the introduction of this selective relaxant binding agent, rapid and reliable neuromuscular reversal from any depth of block became possible. Sugammadex can reverse neuromuscular blockade without the muscarinic side effects typically associated with the administration of acetylcholinesterase inhibitors. However, what remained unchanged is the incidence of residual neuromuscular blockade. It is known that sugammadex cannot always prevent its occurrence, if appropriate dosing is not chosen based on the level of neuromuscular paralysis prior to administration determined by objective neuromuscular monitoring. Alternatively, excessive doses of sugammadex administered in an attempt to ensure full and sustained reversal may affect the effectiveness of rocuronium in case of immediate reoperation or reintubation. In such emergent scenarios that require onset of rapid and reliable neuromuscular blockade, the summary of product characteristics (package insert) recommends using benzylisoquinolinium neuromuscular blocking agents or a depolarizing agent. However, if rapid intubation is required, succinylcholine has a significant number of side effects, and benzylisoquinolinium agents may not have the rapid onset required. Therefore, prior administration of sugammadex introduces a new set of potential problems that require new solutions. This novel reversal agent thus presents new challenges and anesthesiologists must familiarize themselves with specific issues with its use (e.g., bleeding risk, hypermagnesemia, hypothermia). This review will address sugammadex administration in such special clinical situations

The Safety and Feasibility of Transesophageal Echocardiography in Patients With Esophageal Stricture.

OBJECTIVES: Expert guidelines consistently list esophageal stricture (ES) as a contraindication to the performance of transesophageal echocardiography (TEE), although anecdotally the authors are aware of patients with ES undergoing TEE without apparent complication. Therefore the authors sought to determine the outcomes of patients with ES who had undergone TEE at their institution. DESIGN: Single-center, retrospective review. SETTING: Academic medical center (clinic and affiliated hospital). PARTICIPANTS: Patients with documented ES who also underwent TEE. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: In a 10-year period, 1,083 TEE reports were generated for 823 patients who had a diagnosis of ES. One case of esophageal perforation occurred (1/1,083 examination reports [0.09%]) in an 85-year-old male with gastroesophageal reflux disease-related ES who had undergone esophageal dilation the same day as the TEE. In 17.2% of the TEE reports reviewed, changes to the conduct of the examination occurred, such as use of a pediatric probe or avoidance of transgastric imaging. In 8% of reviewed examinations, procedural difficulty was recorded. CONCLUSIONS: Patients with nonmalignant ES commonly present for TEE (\u3e100 per year, on average, at the authors\u27 institution). Severe TEE-related esophageal injury rarely occurred in patients with ES. However, changes to the conduct of the TEE examination and procedural difficulty were not infrequent in this group. Clinicians contemplating TEE in patients with ES should prepare for the possibility of altered examination conduct and possible procedural difficulty

Validation of a convolutional neural network that reliably identifies electromyographic compound motor action potentials following train-of-four stimulation: an algorithm development experimental study

Background: International guidelines recommend quantitative neuromuscular monitoring when administering neuromuscular blocking agents. The train-of-four count is important for determining the depth of block and appropriate reversal agents and doses. However, identifying valid compound motor action potentials (cMAPs) during surgery can be challenging because of low-amplitude signals and an inability to observe motor responses. A convolutional neural network (CNN) to classify cMAPs as valid or not might improve the accuracy of such determinations. Methods: We modified a high-accuracy CNN originally developed to identify handwritten numbers. For training, we used digitised electromyograph waveforms (TetraGraph) from a previous study of 29 patients and tuned the model parameters using leave-one-out cross-validation. External validation used a dataset of 19 patients from another study with the same neuromuscular block monitor but with different patient, surgical, and protocol characteristics. All patients underwent ulnar nerve stimulation at the wrist and the surface electromyogram was recorded from the adductor pollicis muscle. Results: The tuned CNN performed highly on the validation dataset, with an accuracy of 0.9997 (99% confidence interval 0.9994–0.9999) and F1 score=0.9998. Performance was equally good for classifying the four individual responses in the train-of-four sequence. The calibration plot showed excellent agreement between the predicted probabilities and the actual prevalence of valid cMAPs. Ten-fold cross-validation using all data showed similar high performance. Conclusions: The CNN distinguished valid cMAPs from artifacts after ulnar nerve stimulation at the wrist with >99.5% accuracy. Incorporation of such a process within quantitative electromyographic neuromuscular block monitors is feasible

The Year in Cardiothoracic and Vascular Anesthesia: Selected Highlights From 2017.

Evans, A. S., Weiner, M., Patel, P. A., Baron, E. L., Gutsche, J. T., Jayaraman, A., Renew, J. R., Martin, A. K., Fritz, A. V., Gordon, E. K., Riha, H., Patel, S., Ghadimi, K., Guelaff, E., Feinman, J. W., Dashell, J., Munroe, R., Lauter, D., Weiss, S. J., Silvay, G., … Ramakrishna, H. (2018). The Year in Cardiothoracic and Vascular Anesthesia: Selected Highlights From 2017. Journal of cardiothoracic and vascular anesthesia, 32(1), 1–13. https://doi.org/10.1053/j.jvca.2017.10.01