Point-of-care washing of allogeneic red blood cells for the prevention of transfusion-related respiratory complications (WAR-PRC): a protocol for a multicenter randomised clinical trial in patients undergoing cardiac surgery.

INTRODUCTION: The transfusion-related respiratory complications, transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO), are leading causes of transfusion-related morbidity and mortality. At present, there are no effective preventive strategies with red blood cell (RBC) transfusion. Although mechanisms remain incompletely defined, soluble biological response modifiers (BRMs) within the RBC storage solution may play an important role. Point-of-care (POC) washing of allogeneic RBCs may remove these BRMs, thereby mitigating their impact on post-transfusion respiratory complications. METHODS AND ANALYSIS: This is a multicenter randomised clinical trial of standard allogeneic versus washed allogeneic RBC transfusion for adult patients undergoing cardiac surgery testing the hypothesis that POC RBC washing is feasible, safe, and efficacious and will reduce recipient immune and physiologic responses associated with transfusion-related respiratory complications. Relevant clinical outcomes will also be assessed. This investigation will enrol 170 patients at two hospitals in the USA. Simon's two-stage design will be used to assess the feasibility of POC RBC washing. The primary safety outcomes will be assessed using Wilcoxon Rank-Sum tests for continuous variables and Pearson chi-square test for categorical variables. Standard mixed modelling practices will be employed to test for changes in biomarkers of lung injury following transfusion. Linear regression will assess relationships between randomised group and post-transfusion physiologic measures. ETHICS AND DISSEMINATION: Safety oversight will be conducted under the direction of an independent Data and Safety Monitoring Board (DSMB). Approval of the protocol was obtained by the DSMB as well as the institutional review boards at each institution prior to enrolling the first study participant. This study aims to provide important information regarding the feasibility of POC washing of allogeneic RBCs and its potential impact on ameliorating post-transfusion respiratory complications. Additionally, it will inform the feasibility and scientific merit of pursuing a more definitive phase II/III clinical trial. REGISTRATION: ClinicalTrials.gov registration number is NCT02094118 (Pre-results).

Randomised trial of intranasal nicotine and postoperative pain, nausea and vomiting in non-smoking women.

BACKGROUND: The primary aim of this study is to test the hypothesis that intranasal nicotine reduces postoperative opioid use among non-smoking women. The second aim is to determine the effects of intranasal nicotine on the incidence of postoperative nausea and vomiting (PONV). METHODS: In this double-blind, randomised placebo-controlled trial, non-smoking women undergoing gynaecological procedures received either 3 mg intranasal nicotine (N=90) or placebo spray (N=89) at the conclusion of surgery. Postoperative opioid use (intravenous morphine equivalents) and PONV rates were recorded during the recovery room (postanaesthesia care unit, PACU) stay and first 24 postoperative hours. RESULTS: From an overall analysis, opioid dose administered within the first 24 h was lower in patients receiving nicotine [median (25th, 75th) 38 (17, 62) mg for placebo vs. 25 (13, 46) mg for nicotine; P=0.012]. Inpatients who received intranasal nicotine used less opioid. From an overall analysis, patients in the nicotine group were more likely to experience nausea (71.1 vs. 56.2% P=0.044), receive rescue antiemetics (57.8 vs. 38.2% P=0.011), and report higher Nausea Verbal Descriptive Scores [2 (0, 2; vs. 1 (0, 2), P=0.006] in PACU. Inpatients who received nicotine were more likely to receive antiemetics (P=0.009) and report higher Nausea Verbal Descriptive Scores (P=0.025) in the PACU. CONCLUSION: Intraoperative use of intranasal nicotine has a sustained opioid-sparing effect in non-smoking women undergoing gynaecological procedures and is associated with a higher frequency of PONV.

Effects of propofol on intraoperative parathyroid hormone monitoring in patients with primary hyperparathyroidism undergoing parathyroidectomy: a randomized control trial.

PURPOSE: Serial measurements of parathyroid hormone (PTH) serum concentrations aid parathyroidectomy surgery. There are concerns that propofol may increase PTH concentrations and/or interfere with PTH assays. The primary purpose of this study is to determine the effects of propofol on PTH concentrations in patients with primary hyperparathyroidism and to determine its effect on PTH assays. METHODS: Thirty patients with primary hyperparathyroidism were assigned randomly to induction and maintenance with either propofol or sevoflurane. Blood samples for PTH assays were obtained pre-induction, immediately after induction, ten minutes after induction, and after excision of parathyroid adenoma. The primary endpoint was the PTH concentration at ten minutes after induction. This endpoint was compared between groups using analysis of covariance adjusting for pre-induction PTH. An in vitro study was performed with four different pools of PTH concentrations that were spiked with increasing concentrations of propofol. Serum PTH was measured in duplicate in each sample and analyzed using repeated measures analysis of variance. RESULTS: At ten minutes after induction, PTH concentrations did not differ significantly between groups (least square mean difference -7.0 pg·mL(-1); 95% confidence interval, -34.2 to +20.2). The PTH level in vitro did not change significantly with increasing propofol concentrations. DISCUSSION: Parathyroid hormone concentrations in patients with primary hyperparathyroidism were not affected by the type of anesthesia (propofol vs sevoflurane). Furthermore, propofol was found not to interfere with PTH assays at clinically relevant concentrations. There is no evidence to support the avoidance of a propofol anesthetic for parathyroid surgery.

Effects of CPAP on gastric pouch pressure after bariatric surgery.

BACKGROUND: The purpose of this study was to determine if the routine use of postoperative continuous positive airway pressure (CPAP) in patients undergoing laparoscopic Roux-en-Y gastric bypass (RYGB) is associated with an increase in transmural gastric pouch pressure, which may create the risk for anastomotic leak. METHODS: Transmural gastric pressures (difference between gastric pouch and bladder pressures) were measured postoperatively [post-anesthesia recovery care unit (PACU) arrival (prior to initiation of CPAP), 5 min, 30 min, and PACU discharge] in 28 patients (19 patients used CPAP, 9 patients did not) following laparoscopic RYGB. Changes in pressure over time were assessed using a generalized estimating equation, taking into account the repeated measurements obtained for each subject. In all cases, two-tailed P values ≤0.05 were considered statistically significant. RESULTS: Among patients that used CPAP, there were no changes in transmural pouch pressure from baseline at any point in time (P = 0.628). However, in patients that did not use CPAP, there was a trend towards increased transmural gastric/pouch pressure (P = 0.053), which could be attributed to a transient decrease in bladder pressure at the 5-min measurement interval. CONCLUSIONS: Application of CPAP did not increase transmural gastric pouch pressure in our bariatric patients; therefore, its use in the post-RYGB patients does not pose a risk for pouch distension, which could lead to the disruption of anastomotic integrity.

Alveolar recruitment and arterial desflurane concentration during bariatric surgery.

BACKGROUND: We investigated whether reversal of intraoperative atelectasis with the lung recruitment maneuver (RM) affects desflurane arterial concentrations during bariatric surgery. METHODS: After anesthetic induction and maintenance with propofol, patients were randomized to receive alveolar RM at intervals (RM group) or not (controls). Desflurane 6% was initiated, and rate of increase of alveolar desflurane concentration (ratio of end-expiratory to inspiratory concentrations, F(A)/F(I)) and desflurane blood concentrations were measured in both groups. Blood and end-tidal desflurane concentrations were also measured after the discontinuation of anesthesia. RESULTS: The RM group had higher intraoperative Pao(2)/Fio(2) compared with the control group (both, P < 0.001). During induction, the rate of increase in blood desflurane concentrations was rapid in both groups. At comparable mechanical ventilation settings, median times to achieve 0.5 mM (approximately 3%) were 2.1 and 1.59 min (P = 0.09) in the control and RM group, respectively. The times to achieve 0.7 mM (approximately 4.2%) desflurane were 15.9 and 9.3 min in the control and RM group, respectively (P = 0.08). Desflurane blood concentrations tended to be higher during the first 30 min after induction in the RM group (P = 0.066). During maintenance or emergence, the blood desflurane concentrations were not different between control and RM groups. Consequently, the time to eye opening did not differ between groups. CONCLUSION: Although the RM during bariatric surgery represents an effective method for improving intraoperative oxygenation, it does not significantly affect the desflurane blood concentrations during anesthesia or its elimination during emergence.