Determining sex-specific preoperative haemoglobin levels associated with intraoperative red blood cell transfusion in cardiac surgery: a retrospective cohort study.

BACKGROUND: Anaemic cardiac surgery patients are at greater risk of intraoperative red blood cell transfusion. This study questions the application of the World Health Organization population-based anaemia thresholds (haemoglobin <120 g L-1 in non-pregnant females and <130 g L-1 in males) as appropriate preoperative optimisation targets for cardiac surgery. METHODS: A retrospective cohort study was conducted on adults ≥18 yr old undergoing cardiopulmonary bypass surgery. Logistic regression was applied to define sex-specific preoperative haemoglobin concentrations with reduced probability of intraoperative red blood cell transfusion for cardiac surgery patients. RESULTS: Data on 4384 male and 1676 female patients were analysed. Binarily stratified multivariable logistic regression odds of receiving intraoperative red blood cell transfusion increased in cardiac surgery patients >45 yr old (odds ratio [OR] 1.84; 95% confidence interval [CI] 1.33-2.55), surgery urgency <30 days (OR 2.03; 95% CI 1.66-2.48), combined coronary artery bypass grafting and valve surgery, or other surgery types (OR 2.24; 95% CI 1.87-2.67), and female sex (OR 1.92; 95% CI 1.62-2.28). The odds decreased by 8.4% with each 1 g L-1 increase in preoperative haemoglobin (OR 0.92; 95% CI 0.91-0.92). Logistic regression predicted females required a preoperative haemoglobin concentration of 133 g L-1 and males 127 g L-1 to have a 15% probability of intraoperative transfusion. CONCLUSIONS: The World Health Organization female anaemia threshold of haemoglobin <120 g L-1 disproportionately disadvantages female cardiac surgery patients. A preoperative haemoglobin concentration ≥130 g L-1 in adult cardiac surgery patients would minimise their overall probability of intraoperative red blood cell transfusion to <15%.

Prophylactic Postoperative High Flow Nasal Oxygen Versus Conventional Oxygen Therapy in Obese Patients Undergoing Bariatric Surgery (OXYBAR Study): a Pilot Randomised Controlled Trial.

BACKGROUND: Patients with obesity are predisposed to a reduction in end-expiratory lung volume (EELV) and atelectasis after anaesthesia. High flow nasal oxygen (HFNO) may increase EELV, reducing the likelihood of postoperative pulmonary complications (PPC). We conducted a pilot randomised controlled trial (RCT) of conventional oxygen therapy versus HFNO after bariatric surgery. The aim was to investigate the feasibility of using electrical impedance tomography (EIT) as a means of assessing respiratory mechanics and to inform the design of a definitive RCT. METHODS: We performed a single-centre, parallel-group, pilot RCT. Adult patients with obesity undergoing elective bariatric surgery were eligible for inclusion. We excluded patients with a known contraindication to HFNO or with chronic lung disease. RESULTS: Fifty patients were randomised in equal proportions. One patient crossed over from conventional O2 to HFNO. Delta EELI was higher at 1 hour in patients receiving HFNO (mean difference = 831 Au (95% CI - 1636-3298), p = 0.5). Continuous EIT beyond 1 hour was poorly tolerated. At 6 hours, there were no differences in PaO2/FiO2 ratio or PaCO2. Only one patient developed a PPC (in the HFNO group) by 6 weeks. CONCLUSIONS: These data suggest that a large-scale RCT of HFNO after bariatric surgery in an 'all-comers' population is likely infeasible. While EIT was an effective means of assessing respiratory mechanics, it was impractical over time. Similarly, the infrequency of PPC precludes its use as a primary outcome. Future studies should focus on identifying patients at the greatest risk of PPC.

Postoperative Pain Management and the Incidence of Ipsilateral Shoulder Pain After Thoracic Surgery at an Australian Tertiary-Care Hospital: A Prospective Audit.

OBJECTIVES: Ipsilateral shoulder pain (ISP) is a common but variably occurring (42%-85%) complication after thoracic surgery. Multiple potential treatments, including upper limb blocks, intrapleural local anaesthetic infiltration, and systemic opioids, have undergone trials, with limited efficacy. Phrenic nerve infiltration is a potential intervention that may prevent ISP. The aim of this study was to assess the incidence and severity of ISP after thoracic surgery at the authors' institution, where phrenic nerve infiltration is commonly used. DESIGN: Observational cohort study. SETTING: A single- center study in a tertiary referral center in Brisbane, Australia. PARTICIPANTS: This study comprised all adult patients undergoing thoracic surgery at a tertiary- care referral center from May to July 2018. MEASUREMENTS AND MAIN RESULTS: Surgical procedures were divided into open thoracotomy, video-assisted thoracic surgery (VATS) and VATS-guided mini-thoracotomy. The primary outcome was a comparison of incidence of ISP among the 3 types of surgical procedures. Data were analyzed using Stata (StataCorp), with significance testing by Kruskal-Wallis equality of populations rank test. A p value of < 0.05 was deemed significant. Sixty thoracic surgeries were performed during the audit period. Nineteen patients had thoracotomies performed for lobectomy or pneumonectomy, all of whom received phrenic nerve infiltration. The incidence of moderate-to-severe ipsilateral shoulder pain among the thoracoctomy cohort was 15.8% (3/19). Of the 36 VATS procedures audited, 7 patients (19.4%) received infiltration of their phrenic nerve, none of whom reported postoperative ISP. Of the remaining twenty-nine patients who did not receive phrenic nerve infiltration, there were 4 cases of moderate-to-severe ipsilateral shoulder pain (11.1%). Four of the 5 patients (80%) who underwent VATS-guided mini-thoracotomies received phrenic nerve infiltration intraoperatively. Three patients reported moderate-to-severe ISP and of these 3 patients, 2 patients had phrenic nerve infiltration, and 1 patient did not receive infiltration. Overall, there were no statistically significant differences in rest or dynamic pain scores across the surgical groups at any time point. Mann-Whitney test revealed that the participants with ISP were significantly older than those without ISP (p = 0.006). However, there were no significant differences in sex or body mass index between those with and without ISP. CONCLUSION: The authors observed a lower (15.8%) incidence of moderate-to-severe ISP among their thoracotomy patients than reported in prior literature. Injection of local anesthetic into the phrenic nerve fat pad at the level of the diaphragm appeared to be an effective and safe surgical intervention that may eliminate a significant cause of ISP. None of the VATS patients who received phrenic nerve infiltration experienced ISP. Postoperative pain in VATS is expected to be reduced by avoiding the use of a rib spreader, severing of the intercostal nerves, and division of muscle tissue, which may account for the lower observed rates of ISP in the VATS cohort who did not receive phrenic nerve infiltration. Further randomized controlled trials are warranted to establish if patients undergoing various VATS procedures benefit from this intervention.

Association of Obesity With Septic Complications After Major Abdominal Surgery: A Secondary Analysis of the RELIEF Randomized Clinical Trial.

Importance: Body mass index (BMI) has been the most common obesity measure to assess perioperative risk; however, cardiometabolic risk is associated with the burden of visceral fat. Definitive evidence on the association of visceral fat measures, such as waist circumference and waist-to-hip ratio (WHR), with postoperative complications is lacking. Objective: To compare the value of waist circumference with the value WHR and BMI in predicting adverse outcomes, including major septic complications and persistent disability, following major abdominal surgery. Design, Setting, and Participants: This planned secondary analysis of the Restrictive vs Liberal Fluid Therapy for Major Abdominal Surgery (RELIEF) randomized clinical trial took place at 47 centers in 7 countries between October 2013 and September 2016, with 90-day follow-up. A total of 2954 adult RELIEF participants were coenrolled in this secondary analysis. Data analysis took place from December 2018 to September 2019. Exposures: Waist circumference, WHR, and BMI measurements. Main Outcomes and Measures: The primary outcomes were 30-day major septic complications and 90-day persistent disability or death. Results: Of 2954 eligible participants, 2755 were included (mean [SD] age, 65.9 [12.9] years; 1426 [51.8%] men) in the final analysis. A total of 564 participants (20.6%) experienced at least 1 major septic complication within 30 days after surgery (sepsis, 265 [9.7%]; surgical site infection, 409 [14.9%]; anastomotic leak, 78 [2.8%]; pneumonia, 104 [3.8%]). Waist circumference had a statistically significantly larger odds ratio (OR) and discrimination indices as well as a smaller prediction error than WHR or BMI for 30-day major septic complications or death (waist circumference: OR, 1.44; 95% CI, 1.28-1.62; P < .001; area under the receiver operating characteristic curve, 0.641; net reclassification index, 0.266; integrated discrimination improvement [score × 104], 152.98; Brier score, 0.162; WHR: OR, 1.15; 95% CI, 1.03-1.28; P = .01; area under the receiver operating characteristic curve, 0.621; net classification index, 0.199; integrated discrimination improvement [score × 104], 28.47; Brier score, 0.164; BMI: OR, 1.33; 95% CI, 1.17-1.50; P < .001; area under the receiver operating characteristic curve, 0.629; net reclassification index, 0.205; integrated discrimination improvement [score × 104], 85.61; Brier score, 0.163) but not for any other outcomes. Conclusions and Relevance: In this secondary analysis of the RELIEF randomized clinical trial, waist circumference was observed to be superior to other adiposity indices in predicting 30-day major septic complications alone or in conjunction with death following elective major abdominal surgery. Findings suggest that waist circumference is a useful adiposity measure that should be incorporated in preoperative risk assessment for such complications. Trial Registration: ClinicalTrials.gov identifier: NCT01424150.

Intraoperative Cerebral Perfusion Disturbances During Transcatheter Aortic Valve Replacement.

BACKGROUND: Transcatheter aortic valve replacement entails profound and unavoidable hemodynamic perturbations that may contribute to the neurological injury associated with the procedure. METHODS: Thirty-one patients were monitored with cerebral oximetry as a surrogate marker of perfusion while undergoing transcatheter aortic valve replacement via a transfemoral approach under general anesthesia to detect intraoperative hypoperfusion insult. Serial neurologic, cognitive, and cerebral magnetic resonance imaging assessments were administered to objectively quantify perioperative neurologic injury and ascertain any association with significant cerebral oximetry disturbances. RESULTS: Cerebral oximetry reacted promptly to rapid ventricular pacing with significant cerebral desaturation, relative to baseline, of greater than 12% and greater than 20% in 12 of 31 (68%) and 9 of 31 (29%) patients, respectively; or to an absolute measurement of less than 50% in 10 of 31 (33%) patients. Hyperemia occurred immediately following relief of aortic stenosis exceeding baseline by greater than 10% and greater than 20% in 14 of 31 (45%) and 5 of 31 (16%) patients. Postoperative cognitive dysfunction was evident in 3 of 31 (10%) patients and new magnetic resonance imaging-defined ischemic lesions were seen in 17 of 28 (61%) patients. No patient experienced clinically apparent stroke. CONCLUSIONS: Cerebral oximetry reacted promptly to rapid ventricular pacing with significant desaturation and hyperemia a common occurrence. However, no association between this intraoperative insult and objective neurologic injury was detected.

The effect of pregabalin and celecoxib on the analgesic requirements after laparoscopic cholecystectomy: a randomized controlled trial.

PURPOSE: Early postoperative pain is a common complaint after elective laparoscopic cholecystectomy. The use of non-opioid medications as a part of multimodal analgesia has been increasingly advocated in the management of acute post-surgical pain. This randomized, double-blinded, placebo-controlled study evaluated the efficacy of pregabalin, celecoxib, and their combination in the management of acute postoperative pain in patients undergoing elective laparoscopic cholecystectomy. METHODS: One hundred ASA I/II patients scheduled to undergo elective laparoscopic cholecystectomy were assigned to receive two perioperative doses, 12 h apart, of either pregabalin alone, celecoxib alone, their combination, or a placebo. Standard anesthetic protocol was followed. The primary outcomes were postoperative pain at rest and with movement. Secondary outcomes were fentanyl requirements and side effects, which were assessed at 1, 2, 4, 8, 12, and 24 h following surgery. Patient satisfaction with pain relief was recorded at discharge. Differences in main outcomes were analyzed using an intention-to-treat approach. RESULTS: There was no statistically significant difference (p > 0.05) between the four groups in terms of outcomes such as rest pain, movement pain, postoperative fentanyl requirements, or changes in anxiety scores. Patients who had only celecoxib had significantly higher satisfaction with pain management (p = 0.013). Patients who had only pregabalin were at three-times-higher odds of having drowsiness (p = 0.040) and four-times-higher odds of having lightheadedness (p = 0.019) when compared with the placebo group. CONCLUSIONS: Pregabalin, celecoxib alone, or in combination offers no analgesic superiority over standard opioid care in the treatment of postoperative pain following laparoscopic cholecystectomy.