Cannabis hyperalgesia: A phenomenon underestimated in the peri-operative period? No abstract available

Effect of positive end-expiratory pressure on gastric insufflation during induction of anaesthesia when using pressure-controlled ventilation via a face mask: A randomised controlled trial BACKGROUND Face mask ventilation (FMV) during induction of anaesthesia is associated with risk of gastric insufflation that may lead to gastric regurgitation and pulmonary aspiration. A continuous positive airway pressure (CPAP) has been shown to reduce gastric regurgitation. We therefore hypothesised that CPAP followed by FMV with positive end-expiratory pressure (PEEP) during induction of anaesthesia would reduce the risk of gastric insufflation. OBJECTIVE The primary aim was to compare the incidence of gastric insufflation during FMV with a fixed PEEP level or zero PEEP (ZEEP) after anaesthesia induction. A secondary aim was to investigate the effects of FMV with or without PEEP on upper oesophageal sphincter (UES), oesophageal body and lower oesophageal sphincter (LES) pressures. DESIGN A randomised controlled trial. SETTING Single centre, Department of Anaesthesia and Intensive Care, Örebro University Hospital, Sweden. PARTICIPANTS Thirty healthy volunteers. INTERVENTIONS Pre-oxygenation without or with CPAP 10 cmH2O, followed by pressure-controlled FMV with either ZEEP or PEEP 10 cmH2O after anaesthesia induction. MAIN OUTCOME MEASURES A combined impedance/manometry catheter was used to detect the presence of gas and to measure oesophageal pressures. The primary outcome measure was the cumulative incidence of gastric insufflation, defined as a sudden anterograde increase in impedance of more than 1 kΩ over the LES. Secondary outcome measures were UES, oesophageal body and LES pressures. RESULTS The cumulative incidence of gastric insufflation related to peak inspiratory pressure (PIP), was significantly higher in the PEEP group compared with the ZEEP group (log-rank test P < 0.01). When PIP reached 30 cmH2O, 13 out of 15 in the PEEP group compared with five out of 15 had shown gastric insufflation. There was a significant reduction of oesophageal sphincter pressures within groups comparing pre-oxygenation to after anaesthesia induction, but there were no significant differences in oesophageal sphincter pressures related to the level of PEEP. CONCLUSION Contrary to the primary hypothesis, with increasing PIP the tested PEEP level did not protect against but facilitated gastric insufflation during FMV. This result suggests that PEEP should be used with caution after anaesthesia induction during FMV, whereas CPAP during pre-oxygenation seems to be safe. TRIAL REGISTRATION ClinicalTrials.gov, identifier: NCT02238691.

Comparison of a simplified nasal continuous positive airways pressure device with nasal cannula in obese patients undergoing colonoscopy during deep sedation: A randomised clinical trial BACKGROUND Continuous positive airways pressure (CPAP) with a CPAP machine and mask has been shown to be more effective at minimising hypoxaemia than other devices under deep sedation. However, the efficacy of a new and simple CPAP device for spontaneously breathing obese patients during colonoscopy is unknown. OBJECTIVE We hypothesised that oxygenation and ventilation in obese patients under deep sedation during colonoscopy using CPAP via a new nasal mask (SuperNO2VA) would be better than routine care with oxygen supplementation via a nasal cannula. DESIGN Randomised study. SETTING Single-centre, June 2017 to October 2017. PATIENTS A total of 174 patients were enrolled and randomly assigned to Mask group or Control group. Thirty-eight patients were excluded and data from 136 patients underwent final analysis. INTERVENTION Patients in the Mask group were provided with nasal CPAP (10 cmH2O) at an oxygen flow rate of 15 l min−1. In the Control group, patients were given oxygen via a nasal cannula at a flow rate of 5 l min−1. MAIN OUTCOME MEASURES The primary outcome was elapsed time from anaesthesia induction to the first airway intervention. RESULTS The elapsed time from anaesthesia induction to the first airway intervention was 19 ± 10 min in the Mask group (n=63) vs. 10 ± 12 min in the Control group (n=73, P < 0.001). In all, 87.5% (56/64) of patients achieved the target CPAP value. More patients in the Control group (63%) received airway intervention than in the Mask group (22%) (P < 0.001). Hypoxaemia (pulse oximeter oxygen saturation, SpO2 < 90%) occurred more frequently in the Control group (22%) than in the Mask group (5%) (P = 0.004). Minute ventilationPostinduction/minute ventilationBaseline and minute ventilationProcedure-end/minute ventilationBaseline was lower in the Control group than in the Mask group (P = 0.007 and 0.001, respectively). CONCLUSION Application of a nasal mask at a target CPAP of 10 cmH2O improves ventilation and decreases the frequency and severity of hypoxaemia. TRIAL REGISTRATION NCT03139448, registered at ClinicalTrials.gov.

Comparison of low and high positive end-expiratory pressure during low tidal volume ventilation in robotic gynaecological surgical patients using electrical impedance tomography: A randomised controlled trial BACKGROUND The appropriate level of positive end-expiratory pressure (PEEP) during intra-operative mechanical ventilation remains unclear. OBJECTIVE The aim of this study was to investigate the effects of different levels of PEEP with low tidal volume (low-VT) ventilation in a steep Trendelenburg position (30°) and pneumoperitoneum on oxygenation, respiratory mechanics and ventilation distribution using electrical impedance tomography. DESIGN A randomised controlled trial. SETTING Single university secondary care centre, conducted from January 2017 to December 2017. PATIENTS Forty female patients, aged 20 to 60 years, and of American Society of Anesthesiologists’ (ASA) physical status 1 or 2, undergoing elective robotic gynaecological surgery were included. INTERVENTION Forty patients were allocated randomly to a PEEP4 (PEEP 4 cmH2O) group or a PEEP8 (PEEP 8 cmH2O) group. MAIN OUTCOME MEASURES The primary outcomes were respiratory mechanics. The secondary outcomes included changes in ventilation distribution across the ventral and dorsal regions of interest and postoperative pulmonary complications (PPCs) using a modified clinical pulmonary infection score. RESULTS There was no difference in PaO2 at any time point. The peak inspiratory pressure (PIP) and mean airway pressure (MPAW) of the PEEP4 group were lower than those of the PEEP8 group (P < 0.001). The oxygenation factor in the PEEP4 group was higher than that in the PEEP8 group during mechanical ventilation at all times. There was no difference in the fractional distribution of end-expiratory ventilation according to region of interest between the two groups. CONCLUSION Both 4 and 8 cmH2O of PEEP with low-VT ventilation can be used for robotic gynaecological surgery that requires a steep Trendelenburg position and pneumoperitoneum. However, 8 cmH2O of PEEP had no benefit over 4 cmH2O of PEEP with respect to oxygenation and improvement of dorsal regional ventilation. TRIAL REGISTRATION The trial was registered at the Clinical Trial Registry of Korea (KCT0002255). https://cris.nih.go.kr

Effect of sevoflurane-based or propofol-based anaesthesia on the incidence of postoperative acute kidney injury: A retrospective propensity score-matched analysis BACKGROUND Propofol may help to protect against ischaemic acute kidney injury (AKI); however, research on this topic is sparse. OBJECTIVE The current study aimed to investigate whether there were differences in the incidence of postoperative AKI after lung resection surgery between patients who received propofol-based total intravenous anaesthesia (TIVA) and those who received sevoflurane-based inhalational anaesthesia. DESIGN A retrospective observational study. SETTING A single tertiary care hospital. PATIENTS Medical records of patients aged 19 years or older who underwent curative lung resection surgery for nonsmall cell lung cancer between January 2005 and February 2018 were examined. MAIN OUTCOME MEASURES After propensity score matching, the incidence of AKI in the first 3 postoperative days was compared between patients who received propofol and those who received sevoflurane. Logistic regression analyses were also used to investigate whether propofol-based TIVA lowered the risk of postoperative AKI. RESULTS The analysis included 2872 patients (1477 in the sevoflurane group and 1395 in the propofol group). After propensity score matching, 661 patients were included in each group; 24 (3.6%) of the 661 patients in the sevoflurane group developed AKI compared with 23 (3.5%) of the 661 patients in the propofol group (95% confidence intervals of difference in incidence −0.019 to 0.022, P = 0.882). The logistic regression analyses revealed that the incidence of AKI was not different in the two groups (odds ratio 0.96, 95% confidence interval 0.53 to 1.71, P = 0.882). CONCLUSION In this retrospective study, no significant difference was found in the incidence of postoperative AKI after lung resection surgery between patients who received propofol-based TIVA and those who received sevoflurane-based inhalational anaesthesia. Considering the methodological limitation of this retrospective study, further studies are required to confirm these results.

Propofol intravenous anaesthesia with desflurane compared with desflurane alone on postoperative liver function after living-donor liver transplantation: A randomised controlled trial BACKGROUND Propofol is an anaesthetic that resembles α-tocopherol and it has been suggested that it protects against ischaemia-reperfusion injury in liver transplantation. Living-donor liver transplantation (LDLT) presents an opportunity to test this hypothesis in both donors and recipients. OBJECTIVES We compared clinical outcomes after LDLT following anaesthesia with propofol and desflurane against desflurane alone. DESIGN A randomised, parallel study. SETTING Single-centre trial, study period June 2014 and May 2017. PATIENTS Sixty-two pairs of adult donors and recipients who underwent LDLT. INTERVENTION Patients were randomised to receive either desflurane balanced anaesthesia or propofol total intravenous anaesthesia combined with desflurane anaesthesia. MAIN OUTCOME MEASURES The primary outcome was peak liver transaminase levels during the first 7 days after surgery. Liver function was assessed at 10 different time-points (before surgery, 1 h after reperfusion, upon arrival in the ICU, and daily until postoperative day 7). Creatinine was measured to evaluate the incidence of acute kidney injury. TNF-α, IL-1β, IL-6 and TGF-β1 were assessed in 31 donors after induction, at hepatectomy and at the end of surgery and in 52 recipients after induction, and 1, 3 and 24 h after reperfusion. RESULTS Peak liver transaminase levels were not significantly different between the two groups. Liver function tests and creatinine were also similar between groups at all time-points. There was no difference in the incidence of postoperative complications, including acute kidney injury. With the exception of higher TNF-α in donors of the Propofol group at hepatectomy (0.60 ± 0.29 vs. 1.03 ± 0.53, P = 0.01) cytokine results were comparable between the two groups. CONCLUSION Despite the simultaneous administration of propofol infusion in both donors and recipients, no improvement in laboratory or surgical outcome was observed after LDLT compared with patients who received desflurane anaesthesia alone. TRIAL REGISTRATION NCT02504138 at clinicaltrials.gov.

Complex effects of continuous vasopressor infusion on fluid responsiveness during liver resection: A randomised controlled trial BACKGROUND Fluid responsiveness is an important factor to consider for fluid volume loading during major surgery. The effect of continuous vasopressor infusion on fluid responsiveness during prolonged major surgery is a concern. OBJECTIVE We hypothesised that continuous vasopressor infusion during major surgery might not exert significant effects on changes in stroke volume variation (SVV) following fluid bolus infusion, and thereby on fluid responsiveness. DESIGN Randomised controlled trial. SETTING University hospital from April 2014 to August 2016. PATIENTS Patients undergoing liver resection who were randomised to receive continuous intravenous infusion of phenylephrine (P group), norepinephrine (N group), or no vasopressor (C group) (n=17/group). Exclusion criteria were cardiac arrhythmia and severe cardiac, pulmonary or renal dysfunction. INTERVENTION Patients received 4 ml kg−1 fluid boluses of 6% hydroxyethyl starch solution when SVV was at least 12%. Vasopressors were administered continuously to maintain the systemic vascular resistance index at more than 1900 dyn s cm−5 m−2. MAIN OUTCOME MEASURES Cardiac index and SVV were measured using the FloTrac™/Vigileo™ system (Version 4.00). The number of fluid boluses with fluid responsiveness (i.e. >15% increase in cardiac index) was compared between groups using multilevel logistic regression analysis. RESULTS Numbers of fluid responsive boluses in the C, P and N groups were 12 (14%), 22 (34%) and 19 (27%), respectively. Odds ratios on fluid responsiveness for phenylephrine and norepinephrine compared with the control were 3.65 (97.5% confidence interval, 1.15 to 11.6; P = 0.012) and 2.56 (97.5% confidence interval, 0.82 to 8.00; P = 0.064), respectively. Decreases in SVV after fluid bolus infusion for the P and N groups were comparable with the C group (P = 0.23 and 0.53, respectively). CONCLUSION Continuous administration of phenylephrine increased fluid responsiveness during liver resection, suggesting complex effects of continuous vasopressor infusion involving changes in cardiac preload and afterload. TRIAL REGISTRATION UMIN000011024.

Colour Doppler ultrasound after major cardiac surgery improves diagnostic accuracy of the pulmonary infection score in acute respiratory failure: A prospective observational study BACKGROUND Postoperative pneumonia is a frequent complication after cardiac surgery, and its diagnosis is difficult. Little is known about the diagnostic accuracy of lung ultrasound (LUS) in the detection of pneumonia in cardiac surgical patients. The substitution of chest radiography by colour Doppler LUS (LUS-sCPIS) in the simplified clinical pulmonary infection score (sCPIS) could improve the diagnosis of pneumonia following cardiac surgery. OBJECTIVE The aim of this study was to compare the diagnostic accuracy of LUS-sCPIS and of sCPIS alone in the detection of postoperative pneumonia after cardiac surgery. DESIGN A prospective study of diagnostic accuracy. SETTING A Surgical Intensive Care Unit of a French University Hospital. PATIENTS Fifty-one patients with acute respiratory failure within 72 h after cardiac surgery were enrolled between January and May 2015. MAIN OUTCOME MEASURE The two index tests, LUS-sCPIS and sCPIS, were calculated for all patients at the onset of acute respiratory failure. The reference standard for the diagnosis of pneumonia was based on the consensus of three physicians, blind to the sCPIS and LUS-sCPIS data, based on a posthoc review of all the clinical, radiological and microbiological evidence. The diagnostic accuracy of LUS-sCPIS was compared with that of sCPIS in the detection of postoperative pneumonia. RESULTS Pneumonia was diagnosed in 26 out of 51 patients. The LUS-sCPIS detected the presence of pneumonia with a sensitivity of 92% (95% CI 0.85 to 0.99) and a specificity of 68% (95% CI 0.55 to 0.81). The sCPIS detected the presence of pneumonia with a sensitivity of 35% (95% CI 0.22 to 0.48) and a specificity of 84% (95% CI 0.74 to 0.94). The area under the curve (AUC) of LUS-sCPIS at 0.80 (95% CI 0.69 to 0.91) was higher than the AUC of sCPIS at 0.59 (95% CI 0.47 to 0.71; P = 0.0008). CONCLUSION Compared with sCPIS, LUS-sCPIS improved diagnostic accuracy in the detection of postoperative pneumonia in patients with acute respiratory failure after cardiac surgery. It could be a useful bedside tool to guide pneumonia management. TRIAL REGISTRATION Clinicaltrials.gov identifier: NCT03279887.

Validation of 3-minute diagnostic interview for CAM-defined Delirium to detect postoperative delirium in the recovery room: A prospective diagnostic study BACKGROUND Recent guidelines on postoperative delirium (POD) recommend POD screening in all patients, using a validated tool, starting in the recovery room. An operationalisation of the Confusion Assessment Method (CAM) criteria, the 3-Minute Diagnostic Interview for CAM-defined Delirium (3D-CAM), has been developed for use in general medical units. OBJECTIVES The aim of this study was to evaluate 3D-CAM performance in an adult patient population to detect POD in the recovery room. DESIGN A prospective diagnostic study. SETTING Recovery room of a tertiary care university hospital in Berlin, Germany, in 2017. PATIENTS Patients at least 18 years of age undergoing elective surgery. MAIN OUTCOME MEASURES Patients were subjected to evaluation by blinded investigators using the 3D-CAM and the Diagnostic and Statistical Manual of Mental Disorders 5 (DSM-5, reference standard). Sensitivity, specificity and positive predictive value (PPV) and negative predictive value (NPV) were analysed for 3D-CAM, in addition to test–retest and inter-rater reliability analyses. RESULTS Sixteen out of 176 patients (9.1%) developed POD. The 3D-CAM demonstrated strong test performance (specificity 0.88, sensitivity 1.0, area under the curve 0.94, PPV 0.44 and NPV 1.0), with a test–retest reliability of 90% (n = 10) and inter-rater reliability of 80% (n = 10). CONCLUSION In this diagnostic study, 3D-CAM showed strong performance for detection of POD in the recovery room. Due to the low training requirements, fast application and high sensitivity, it might be particularly appropriate for clinical staff with limited experience in the assessment of POD. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT02992717

Pre-operative assessment of 30-day mortality risk after major surgery: the role of the quick sequential organ failure assessment: A retrospective observational study BACKGROUND The quick Sequential Organ Failure Assessment (qSOFA) is intended for the assessment of the prognosis and risk of sepsis. It may also help predict the mortality risk of nonseptic patients. OBJECTIVE This study investigated the relationship between pre-operative qSOFA scores and 30-day mortality after major surgery. It also evaluated the predictive value of qSOFA scores combined with the American Society of Anesthesiologists (ASA) physical status and Charlson comorbidity index (CCI). DESIGN A retrospective observational study. SETTING Single tertiary academic hospital. PATIENTS Medical records of patients who underwent major surgery (estimated blood loss >500 ml; surgery time >2 h) between January 2010 and December 2017 were examined. MAIN OUTCOME MEASURES The qSOFA score was measured within 24 h before surgery, and its association with 30-day mortality was analysed using multivariable logistic regression. A receiver-operating characteristic curve analysis was used to investigate the predictive power of the pre-operative qSOFA scores combined with the ASA physical status and with CCI. RESULTS A total of 6336 patients were included in the final analysis, and 91 (1.4%) died within 30 days. The multivariable logistic regression analysis including all covariates indicated that 30-day mortality was 2.43-times higher for the score 1 group than for the score 0 group (P = 0.002), and it was 3.54-times higher for the score at least 2 group than for the score 0 group (P < 0.001). The area under the curve (AUC) of the pre-operative qSOFA, ASA physical status and CCI were 0.69, 0.55 and 0.57, respectively. When the pre-operative qSOFA score was combined with the ASA physical status or CCI, the AUCs were 0.73 and 0.72, respectively. CONCLUSION Higher pre-operative qSOFA scores within 24 h of surgery were associated with increased 30-day mortality. Pre-operative qSOFA scores have better predictive value for 30-day mortality when combined with the ASA physical status or CCI.