Postoperative hyperlactataemia and preoperative cardiopulmonary exercise testing in an elective noncardiac surgical cohort: a retrospective observational study.

Background: Blood lactate concentration in the postoperative period is a marker of physiological stress and a predictor of complications and mortality. Cardiopulmonary exercise testing (CPET) is a common preoperative risk stratification tool. We aimed to investigate the association between preoperative CPET results and postoperative lactate concentration with postoperative mortality after major noncardiac surgery. Methods: We analysed data from patients undergoing major noncardiac surgery in a tertiary UK centre between 2007 and 2014 who had preoperative CPET and postoperative lactate measurements. Univariate and multivariate analyses were performed to assess the association between lactate concentration, CPET results, or both and mortality. Results: We analysed data from 1075 patients. A mean lactate concentration >2 mM in the first 12, 24, and 48 h after surgery was associated with odds ratios (ORs) and 95% confidence intervals (CIs) for 30-day mortality of 3.9 (2.1-7.3; P<0.005), 4.5 (2.4-8.4; P<0.005), and 6.1 (3.3-11.5; P<0.005), respectively. The dichotomous CPET variable, ventilatory equivalence for CO2 (V̇E/V̇co2; cut-off 34), was associated with increased risk of 30-day mortality (OR 2.5; 95% CI: 1.3-4.8; P<0.005). In a multivariable model, hyperlactataemia and poor V̇E/V̇co2 retained their significant associations with 30- and 90-day mortality when adjusted for age, BMI, and surgical risk. When looking at the combined effect of the dichotomous hyperlactataemia in the first 24 h (cut-off 2 mM) and preoperative V̇E/V̇co2, the OR for 30-day mortality was 11.53 (95% CI: 4.6-28.8; P≤0.005). Conclusions: Our study suggests that postoperative hyperlactataemia and preoperative poor V̇E/V̇co2 are independently associated with an increased risk of mortality after major noncardiac surgery.

Efficacy of supervised exercise prehabilitation programs to improve major abdominal surgery outcomes: A systematic review and meta-analysis.

The optimal package of components for a prehabilitation intervention remains unclear. The aim was to determine the efficacy of supervised exercise prehabilitation programs to enhance patient fitness and improve surgical outcomes. The protocol was preregistered (PROSPERO: CRD42020180693). PubMed, MEDLINE, CINAHL, AMED, CENTRAL, PeDro, ClinicalTrials.gov and the WHO International Clinical Trials Registry were searched. Randomized controlled trials (RCTs) of supervised prehabilitation programs before major abdominal surgery were included. Physical function, cardiorespiratory capacity and surgical outcomes were the primary outcomes measures. Risk of bias was assessed according to the Cochrane Risk of Bias 1.0 tool for RCTs. Data are summarized narratively, and where possible, quantitavely. Meta-analyses results are reported as risk ratios (RR), mean difference of changes between baseline and follow-up time points or mean difference between groups and 95% confidence interval (CI). Twenty RCTs were included in the analysis with a total of 1258 patients. The average 6-min walking distance change was +33 m in the prehabilitation group compared to the usual care (UC) group after prehabilitation (95% CI: [13, 53], P < 0.01). Only in studies with more than one supervised session per week changes in 6-min-walk distance were significantly higher in the prehabilitation group compared to the UC group after prehabiliatation (Mean difference: 47 m, 95% [CI]: [20-75], P < 0.01). The change in peak volume of oxygen uptake during a maximum cardiopulmonary test was +1.47 mL·kg-1·min-1 in the prehabilitation group compared to the UC group (95% CI: [0.68, 2.25], P < 0.01). There was no significant difference in the change in oxygen uptake at anaerobic threshold between groups (Mean differences: 0.47, 95% CI: [-0.16, 1.10], P:0.14). Post-operative complications incidence was similar between groups (RR: 0.80, 95% CI: [0.61, 1.05], P:0.11), irrespective of the frequency of supervised session per week (RR: 0.67, 95% CI: [0.43, 1.03], P:0.07). In conclusion, prehabilitation programmes with more than one supervised session per week improved physical function but did not enhance surgical outcomes.

Delta sleep-inducing peptide alters bispectral index, the electroencephalogram and heart rate variability when used as an adjunct to isoflurane anaesthesia.

BACKGROUND AND OBJECTIVE: Delta sleep-inducing peptide (DSIP) is an endogenous peptide that crosses the blood-brain barrier, named after its association with natural sleep and enhanced electroencephalogram (EEG) delta rhythm. The objective of this study was to determine whether DSIP could be used as an adjunct to volatile anaesthesia in humans, our hypothesis being that DSIP is a natural hypnotic that would increase anaesthetic depth. The aims were to assess depth of anaesthesia using bispectral index (BIS), the EEG and heart rate variability (HRV), and to determine whether DSIP altered the symmetry of EEG between the left and right cerebral hemispheres. METHODS: Twenty-four female ASA I or II patients gave written, informed consent to a protocol approved by our local research ethics committee. Twelve were randomly assigned as controls to receive saline. The other 12 were randomly allocated to receive one of three intravenous bolus doses of DSIP (Clinalfa) at 25, 50 or 100 nmol kg(-1). The first administration of DSIP was while awake and the second after induction of anaesthesia with propofol and maintenance with isoflurane. BIS and EEG parameters were measured continuously using a bilateral electrode montage. RESULTS: DSIP significantly increased heart rate, decreased HRV and, paradoxically, significantly reduced delta rhythm along with reducing burst suppression and increasing BIS at 25 nmol kg(-1) during isoflurane anaesthesia. DSIP also significantly altered bilateral symmetry of EEG. CONCLUSION: DSIP probably reduced parasympathetic tone and decreased (lightened) the depth of anaesthesia measured using BIS.

CPET and cardioesophagectomy: A single centre 10-year experience.

INTRODUCTION: CPET is a routine investigation prior to cardioesophagectomy. Over a 10-year period 200 patients had CPET before elective cardioesophagectomy. We examine the relationship between CPET and outcomes in these patients. MATERIALS AND METHODS: Complication data were prospectively collected using the Clavien-Dindo system. Logistic regression analysis was used to determine whether 90-day mortality and morbidity were significantly different between fitter and less fit patients. RESULTS: 90-day mortality was 5.5%. In univariate analysis the following factors were associated with a significantly increased risk of death at 90 days: anaerobic threshold <11 ml kg-1 min-1 OR (95% CI) = 4.38 (1.23,15.6), p = 0.023; V̇O2 peak <15 ml kg-1 min-1 O2 OR (95% CI) = 5.0 (1.42,15.55), p = 0.012; V̇E/V̇CO2 > 34 OR (95% CI) = 4.07 (1.19,14.0), p = 0.026; diabetes mellitus OR (95% CI) = 5.76 (1.55,21.35) p = 0.009. In multivariate logistic regression analysis both diabetes (OR = 5.76 [1.55,21.4] p = 0.009) and presence of ≥ 1 subthreshold CPET value (OR = 6.72 [1.32,29.8] p = 0.021) were significantly associated with increased risk of death at 90 days. Median (95% CI) survival for patients who had a CPET with 'normal' parameters was 1176 (565, 1787) days, compared with 642 (336, 948) days for patients with ≥ one subthreshold parameter. 15.5% of patients had ECG ischaemia; there were no deaths in this group. CONCLUSION: Presence of at least one sub-threshold CPET value at pre-operative testing is associated with increased risk of 90-day mortality and shorter long term survival. These results allow us to better define risks during shared decision-making with patients.