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%.

Polyhexamethylene biguanide discs versus unmedicated dressings for prevention of central venous catheter-associated infection in the intensive care unit: A pilot randomised controlled trial to assess protocol safety and feasibility.

BACKGROUND: Central venous catheters are prone to infectious complications, affecting morbidity, mortality and healthcare costs. Polyhexamethylene biguanide-impregnated discs at the catheter insertion site may prevent local and bloodstream infection; however, efficacy has not been established in a critical care setting. OBJECTIVE: The objective of this study was to pilot test polyhexamethylene biguanide-impregnated discs compared to standard unmedicated dressings for central venous catheter infection prevention in critically ill patients. METHODS: This was a single-centre pilot randomised controlled trial. Adults admitted to intensive care requiring a central venous catheter for >72 h were eligible. Patients with a current bloodstream infection, concurrent central venous catheter, chlorhexidine or polyhexamethylene biguanide allergy, or sensitive skin were excluded. Patients were randomised to receive standard central venous catheter dressings with/without polyhexamethylene biguanide discs. OUTCOME MEASURES: The primary outcome was feasibility, defined by patient eligibility, recruitment, retention, protocol adherence, missing data, and staff satisfaction. Secondary outcomes included: central line-associated infection; primary bloodstream infection; local infection; skin complications; device/dressing dwell time; serious adverse events, and cost-effectiveness. RESULTS: Of 309 patients screened, 80 participants were recruited with 98% (n = 78) receiving an internal jugular catheter which dwelled for a median of 5 days (interquartile range = 4.0, 6.0). Feasibility criteria were predominantly met (recruitment 88%; retention 100%; protocol fidelity 91%); however, eligibility criteria were not met (32%; most commonly owing to short predicted catheter dwell). Staff acceptability criteria were met, with 83% of staff scoring dressing application and removal ≥7 on a numerical rating scale. There were no central line-associated bloodstream infections and no local infections. Insertion site itch occurred in 4% (control [n = 0], intervention [n = 3]) of participants, while 32% (24/76) reported pain, and 46% (35/76) tenderness. CONCLUSIONS: Polyhexamethylene biguanide discs appear safe for central venous catheter infection prevention. Feasibility of a large efficacy trial was established with some modifications to screening processes. Large, adequately powered randomised controlled trials are needed to test the infection prevention hypotheses.

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.

A pilot randomised controlled trial of dressing and securement methods to prevent arterial catheter failure in intensive care.

BACKGROUND: Critically ill patients in an intensive care setting often require arterial catheters for blood pressure monitoring and arterial blood collection. Arterial catheter failure, which manifests in both mechanical and infective forms, remains common. Dressing and securement inadequacies may impact this failure; however, the best method for dressing and securing arterial catheters is yet to be determined. OBJECTIVES: The objective of this study was to establish the feasibility of a definitive randomised controlled trial comparing methods for dressing and securing arterial catheters and to prevent device failure in an adult intensive care setting. METHODS: A pilot, parallel-group, randomised controlled trial was conducted between April 2017 and June 2018. Patients receiving treatment in two adult intensive care units (Queensland, Australia) were eligible for inclusion and were allocated to receive either (i) an integrated securement dressing or (ii) a simple polyurethane dressing (with gauze/foam), applied to their newly inserted arterial catheters. MAIN OUTCOME MEASURES: Primary outcomes were (i) feasibility (defined by pre-established criteria: patient eligibility, consent, protocol adherence, retention, and staff acceptability) and (ii) all-cause arterial catheter failure (a composite of local and bloodstream infection, occlusion, dislodgement, infiltration/extravasation, arterial inflammation, thrombosis, and/or inaccurate trace). Secondary outcomes included: failure type, dwell time, dressing adhesion, adverse event profiles, and staff acceptability. RESULTS: In total, 109 patients were studied (n = 53 integrated securement dressing; n = 56 simple polyurethane). The feasibility criterion was met by most patients (including rates of consent [86%], protocol adherence [93%], and retention [100%]); however, the criteria for patient eligibility were not met (73%). All-cause device failure did not differ significantly between the integrated securement device group (n = 12/53, 23%) and the simple polyurethane group (n = 6/56, 11%) (hazard ratio = 2.39, 95% confidence interval = 0.89-6.37, p = 0.083). CONCLUSIONS: Findings indicate a larger study is feasible, with minor alterations to recruitment methods required. Arterial catheter failure remains unacceptably common; further research to determine optimal dressing/securement practices is urgently needed.

Percutaneous Transvenous Mitral Valve-in-Valve Implantation Using Commercially Available Transcatheter Valve. First Australian Experience.

In patients with a degenerative mitral bioprosthesis and prohibitive surgical risk there is emerging evidence for the feasibility of valve-in-valve procedures via a percutaneous transvenous transseptal approach. This paper describes the first time this procedure has been performed in Australia.

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.

Anaesthesia healthcare workers' interactions with COVID-19-positive and -suspect patients: A multi-site observational study from Queensland, Australia.

Occupationally acquired COVID-19 is a hazard for healthcare workers (HCWs). In four hospitals of the Metro North Hospitals and Health Service in Queensland, Australia, we invited HCWs to report the nature of any anaesthesia interactions with COVID-19-positive and COVID-19-suspect patients. This was to assist workforce planning in future pandemics. Data collection consisted of three phases; 1) participating HCWs recorded details of episodes of care (EOCs) with COVID-19-positive or COVID-19-suspect patients; 2) these HCWs were invited to complete a follow-up survey about their own health status regarding COVID-19 infections; 3) electronic health records were used to assess patient demographics, infectious status and outcomes. Between 21 March 2020 and 17 May 2022, 63 anaesthesia HCWs reported 90 EOCs with 67 unique patients. The median (interquartile range (IQR)) age of the HCWs was 40.5 years (34-46); 55% (34/62) were male, 62% (39/63) were consultants and 21% (13/63) were registrars. The median (IQR) age of patients was 39 (28-63) years. Personal protective equipment (PPE) was deemed to be appropriate by the HCWs in (86/88) 98% of the EOCs. Twenty-four HCWs (38%) responded to a follow-up survey. Of 12 HCWs who subsequently tested positive to COVID-19, only four had cared for a COVID-19-positive patient in the two weeks prior to their diagnosis. Most responding HCWs perceived they contracted COVID-19 in the community, experiencing mild illness. We found relatively low COVID-19 case numbers, high PPE use and low transmission of COVID-19 within the hospital setting.

Fluid resuscitation after cardiac surgery in the intensive care unit: A bi-national survey of clinician practice. (The FRACS-ICU clinician survey).

Context and Aims: To describe current fluid and vasopressor practices after cardiac surgery in Australia and New Zealand cardiothoracic intensive care units (ICU). Design and Setting: This web-based survey was conducted in cardiothoracic ICUs in Australia and New Zealand. Methods: Intensivists, cardiac surgeons, and anesthetists were contacted to complete the online survey that asked questions regarding first and second choice fluids and vasopressors and the tools and factors that influenced these choices. Results: There were 96 respondents including 51 intensivists, 27 anesthetists, and 18 cardiac surgeons. Balanced crystalloids were the most preferred fluids (70%) followed by 4% albumin (18%) overall and among intensivists and anesthetists; however, cardiac surgeons (41%) preferred 4% albumin as their first choice. The most preferred second choice was 4% albumin (74%). Among vasopressors, noradrenaline was the preferred first choice (93%) and vasopressin the preferred second choice (80%). 53% initiated blood transfusion at a hemoglobin threshold of 70 g/L. Clinical acumen and mean arterial pressure were the most commonly used modalities in determining the need for fluids. Conclusions: There is practice variation in preference for fluids used in cardiac surgical patients in Australia and New Zealand; however, balanced crystalloids and 4% albumin were the most popular choices. In contrast, there is broad agreement with the use of noradrenaline and vasopressin as first and second-line vasopressors. These data will inform the design of future studies that aim to investigate hemodynamic management post cardiac surgery.

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.

Successful outcome in pregnancy with arterial tortuosity syndrome.

BACKGROUND: Arterial tortuosity syndrome is a rare, autosomal recessive, severe, connective tissue disorder caused by a mutation in the SLC2A10 gene. We describe the pregnancy and delivery with this high-risk connective tissue disorder involving generalized abnormalities of the vasculature. CASE: A woman with an undefined connective tissue disorder was referred for tertiary prenatal care. Diagnostic imaging demonstrated multiple pulmonary artery aneurysms and arterial tortuosity, consistent with a clinical diagnosis of arterial tortuosity syndrome. With a team considering all potential complications, a delivery plan was undertaken involving cesarean delivery and intensive perioperative and postpartum monitoring. The outcome was optimal for mother and neonate. Concurrent molecular testing demonstrated homozygosity for the SLC2A10 gene. CONCLUSION: Optimal maternal, fetal and neonatal outcomes were obtained with comprehensive multidisciplinary care and close maternal and fetal surveillance.

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.

Study Protocol for a Pilot, Open-Label, Prospective, and Observational Study to Evaluate the Pharmacokinetics of Drugs Administered to Patients during Extracorporeal Circulation; Potential of In Vivo Cytochrome P450 Phenotyping to Optimise Pharmacotherapy.

Pharmacokinetic alterations of medications administered during surgeries involving cardiopulmonary bypass (CPB) and extracorporeal membrane oxygenation (ECMO) have been reported. The impact of CPB on the cytochrome P450 (CYP) enzymes' activity is the key factor. The metabolic rates of caffeine, dextromethorphan, midazolam, omeprazole, and Losartan to the CYP-specific metabolites are validated measures of in vivo CYP 1A2, 2D6, 3A4, 2C19, and 2C9 activities, respectively. The study aim is to assess the activities of major CYPs in patients on extracorporeal circulation (EC). This is a pilot, prospective, open-label, observational study in patients undergoing surgery using EC and patients undergoing laparoscopic cholecystectomy as a control group. CYP activities will be measured on the day, and 1-2 days pre-surgery/3-4 days post-surgery (cardiac surgery and Laparoscopic cholecystectomy) and 1-2 days after starting ECMO, 1-2 weeks after starting ECMO, and 1-2 days after discontinuation from ECMO. Aforementioned CYP substrates will be administered to the patient and blood samples will be collected at 0, 1, 2, 4, and 6 h post-dose. Major CYP enzymes' activities will be compared in each participant on the day, and before/after surgery. The CYP activities will be compared in three study groups to investigate the impact of CYPs on EC.

High flow nasal oxygen after bariatric surgery (OXYBAR), prophylactic post-operative high flow nasal oxygen versus conventional oxygen therapy in obese patients undergoing bariatric surgery: study protocol for a randomised controlled pilot trial.

BACKGROUND: The incidence of obesity is increasing worldwide. In selected individuals, bariatric surgery may offer a means of achieving long-term weight loss, improved health, and healthcare cost reduction. Physiological changes that occur because of obesity and general anaesthesia predispose to respiratory complications following bariatric surgery. The aim of this study is to determine whether post-operative high flow nasal oxygen therapy (HFNO2) improves respiratory function and reduces the incidence of post-operative pulmonary complications (PPCs) in comparison to conventional oxygen therapy in these patients. METHOD: The OXYBAR study is a prospective, un-blinded, single centre, randomised, controlled pilot study. Patients with body mass index (BMI) > 30 kg/m2, undergoing laparoscopic bariatric surgery, will be randomised to receive either standard low flow oxygen therapy or HFNO2 in the post-operative period. The primary outcome measure is the change in end expiratory lung impedance (∆EELI) as measured by electrical impedance tomography (EIT). Secondary outcome measures include change in tidal volume (∆Vt), partial arterial pressure of oxygen/fraction of inspired oxygen (PaO2/FiO2) ratio, incidence of PPCs, hospital length of stay and measures of patient comfort. DISCUSSION: We hypothesise that the post-operative administration of HFNO2 will increase EELI and therefore end expiratory lung volume (EELV) in obese patients. To our knowledge this is the first trial designed to assess the effects of HFNO2 on EELV in this population. We anticipate that data collected during this pilot study will inform a larger multicentre trial. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN12617000694314 . Registered on 15 May 2017.

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.

Wrist acupressure for post-operative nausea and vomiting (WrAP): A pilot study.

Post-operative nausea and vomiting are undesirable complications following anaesthesia and surgery. It is thought that acupressure might prevent nausea and vomiting through an alteration in endorphins and serotonin levels. In this two-group, parallel, superiority, randomised control pilot trial we aimed to test pre-defined feasibility outcomes and provide preliminary evidence for the efficacy of PC 6 acupoint stimulation vs. placebo for reducing post-operative nausea and vomiting in cardiac surgery patients. Eighty patients were randomly assigned to either an intervention PC 6 acupoint stimulation via beaded intervention wristbands group (n=38) or placebo sham wristband group (n=42). The main outcome was assessment of pre-defined feasibility criteria with secondary outcomes for nausea, vomiting, rescue anti-emetic therapy, quality of recovery and adverse events. Findings suggest that a large placebo-controlled randomised controlled trial to test the efficacy of PC 6 stimulation on PONV in the post-cardiac surgery population is feasible and justified given the preliminary clinically significant reduction in vomiting in the intervention group in this pilot. The intervention was tolerated well by participants and if wrist acupressure of PC 6 acupoint is proven effective in a large trial it is a simple non-invasive intervention that could easily be incorporated into practice.