Identifying the limitations of cardiopulmonary exercise testing prior to esophagectomy using a pooled analysis of patient-level data.

Preoperative cardiopulmonary exercise testing (CPET) provides an objective assessment of aerobic fitness in patients undergoing surgery. While peak oxygen uptake during exercise (VO2peak) and anaerobic threshold have demonstrated a moderate correlation with the development of complications following esophagectomy, no clinically useful threshold values have been defined. By pooling patient level data from existing studies, we aimed to define optimal thresholds for preoperative CPET parameters to predict patients at high risk of postoperative complications. Studies reporting on the relationship between preoperative CPET variables and post-esophagectomy complications were determined from a comprehensive literature search. Patient-level data were obtained from six contributing centers for pooled-analyses. Outcomes of interest included cardiopulmonary and non-cardiopulmonary complications, unplanned intensive care unit readmission, and 90-day and 12-month all-cause mortality. Receiver operating characteristic curves and logistic regression models estimated the predictive value of CPET parameters for each individual outcome of interest. This analysis comprised of 621 patients who underwent CPET prior to esophagectomy during the period from January 2004 to March 2017. For both anaerobic threshold and VO2peak, none of the receiver operating characteristic curves achieved an area under the curve value > 0.66 for the outcomes of interest. The discriminatory ability of CPET for determining high-risk patients was found to be poor in patients undergoing an esophagectomy. CPET may only carry an adjunct role to clinical decision-making.

Findings of a feasibility study of pre-operative pulmonary rehabilitation to reduce post-operative pulmonary complications in people with chronic obstructive pulmonary disease scheduled for major abdominal surgery.

Background: Patients with chronic obstructive pulmonary disease (COPD) are at increased risk of complications and death following surgery. Pulmonary complications are particularly prominent.  Pulmonary rehabilitation is a course of physical exercise and education that helps people with COPD manage their condition.  Although proven to improve health outcomes in patients with stable COPD, it has never been formally tested as a pre-surgical intervention in patients scheduled for non-cardiothoracic surgery.  If a beneficial effect were to be demonstrated, pulmonary rehabilitation for pre-surgical patients with COPD might be rapidly implemented across the National Health Service, as pulmonary rehabilitation courses are already well established across much of the United Kingdom (UK). Methods: We performed a feasibility study to test study procedures and barriers to identification and recruitment to a randomised controlled trial testing whether pulmonary rehabilitation, delivered before major abdominal surgery in a population of people with COPD, would reduce the incidence of post-operative pulmonary complications.  This study was run in two UK centres (Oxford and Newcastle upon Tyne). Results:  We determined that a full randomised controlled trial would not be feasible, due to failure to identify and recruit participants.  We identified an unmet need to identify more effectively patients with COPD earlier in the surgical pathway.  Service evaluations suggested that barriers to identification and recruitment would likely be the same across other UK hospitals. Conclusions:  Although pulmonary rehabilitation is a potentially beneficial intervention to prevent post-operative pulmonary complications, a randomised controlled trial is unlikely to recruit sufficient participants to answer our study question conclusively at the present time, when spirometry is not automatically conducted in all patients planned for surgery.  As pulmonary rehabilitation is a recommended treatment for all people with COPD, alternative study methods combined with earlier identification of candidate patients in the surgical pathway should be considered. Trial registration: ISRCTN29696295, 31/08/2017.

Impaired cardiopulmonary reserve in an elderly population is related to postoperative morbidity and length of hospital stay after radical cystectomy.

OBJECTIVE: To determine the relationship of preoperatively measured cardiorespiratory function, to the development of postoperative complications and length of hospital stay (LOS) in a cohort of patients undergoing radical cystectomy (RC), as RC and conduit formation is curative but is associated with significant postoperative morbidity and mortality. PATIENTS AND METHODS: Consecutive patients planned to have RC underwent cardiopulmonary exercise testing (CPET) to a standardised protocol. The results of the CPET were 'blinded' from the clinicians involved in the care of the patients. Patients were prospectively monitored for the primary outcome of postoperative complications, as defined by a validated classification (Clavien-Dindo). Secondary outcome included LOS and mortality. RESULTS: In all, 82 patients underwent CPET before RC. Eight patients did not subsequently undergo RC and a further five did not exercise sufficiently to allow for appropriate determination of the cardiopulmonary variables of interest. There was a significant difference in LOS between those patients who had a major perioperative complication (Clavien score > 3) and those that did not (16 vs 30 days; P < 0.001; hazard ratio [HR] 3.6, 95% confidence interval [CI] 2.1-6.3). The anaerobic threshold (AT) remained as the only significant independent predictor variable for the presence or absence of major postoperative complications (odds ratio 0.74, 95% CI 0.57-0.97; P = 0.03). When the optimal predictive value of AT of 12 mL/min/kg was used as a fitness marker, there was a significant relationship between fitness and LOS (median LOS: 'unfit' 22 days vs 'fit' 16 days; HR 0.47, 95% CI 0.28-0.80; P = 0.006) CONCLUSION: Impaired preoperative cardiopulmonary reserve was related to major morbidity, prolonged LOS and increased use of critical care resource after RC. This has important health and economic implications for risk assessment, rationalisation of postoperative resource and the potential for therapeutic preoperative intervention with exercise therapy.

Preoperative optimization: rationale and process: is it economic sense?

PURPOSE OF REVIEW: The development of preoperative clinics and the increasing importance of the anaesthetist in the management of surgical risk have expanded the concept of preoperative optimization. This review will focus on the rationale and process for cost-effective preoperative optimization. RECENT FINDINGS: Postoperative morbidity, rather than mortality, is the most important surgical outcome in economic terms. Since preoperative comorbidity, in association with surgical complexity, is more predictive of hospital costs than the subsequent treatment of postoperative complications per se, preoperative optimization represents an appropriate economic target. Process management, including guidelines to reduce unnecessary investigations and specialist referrals and enhancing perioperative recovery, makes economical sense in the majority of patients who undergo noncardiac surgery with few complications. Preoperative optimization of a minority of high-risk surgical patients is also important given limited critical care resource. However, the evidence for specific optimization strategies in this latter group continues to evolve and requires further clarification in well designed trials. SUMMARY: The requirement for appropriate methods of risk stratification of surgical patients targeted at the reduction of postoperative morbidity, underpins the development of cost-effective preoperative optimization. Specific process-based and clinical measures may then be applied to the development of individualized perioperative care packages.

Acute lung injury after ruptured abdominal aortic aneurysm repair: the effect of excluding donations from females from the production of fresh frozen plasma.

OBJECTIVES: Transfusion-related acute lung injury may contribute to the development of acute lung injury in the critically ill, due to plasma from female donors containing antileukocyte antibodies. In July 2003, the U.K. National Blood Service stopped using female donor plasma for the production of fresh frozen plasma. Patients undergoing repair of a ruptured abdominal aortic aneurysm receive large amounts of fresh frozen plasma and often develop acute lung injury. We investigated whether the change to male fresh frozen plasma was associated with a change in the frequency of acute lung injury in these patients. DESIGN: A retrospective, before and after, observational, single-center study. SETTING: Tertiary care center and a regional blood center. PATIENTS: The study included 211 patients undergoing open repair of a ruptured abdominal aortic aneurysm between 1998 and 2006. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Primary outcome was the development of acute lung injury in the first 6 hrs after surgery. Secondary outcomes were significant hypoxia (PaO2/FiO2 ratio <300), time to extubation, and survival at 30 days. Groups were well matched and received similar volumes of intravenous fluids and blood components. There was significantly less acute lung injury following the change to male fresh frozen plasma (36% before vs. 21% after, p = .04). At 6 hrs after surgery, fewer patients were hypoxic (87% before vs. 62% after, p < .01). In multivariate analysis, the change in donor policy was associated with a decreased risk of developing acute lung injury (odds ratio 0.39; 95% confidence interval, 0.16-0.90). Time to extubation and survival at 30 days were not statistically different between groups. CONCLUSIONS: The policy to exclude female donors from the production of fresh frozen plasma was associated with a decrease in the frequency of acute lung injury in patients undergoing repair of a ruptured abdominal aortic aneurysm.

Renal tubular injury after infrarenal aortic aneurysm repair.

OBJECTIVE: To investigate markers of tubular injury (glutathione-S-transferase [GST] isoforms) as early markers for renal damage in patients undergoing abdominal aortic aneurysm repair. DESIGN: Prospective study. SETTING: Regional teaching hospital. PARTICIPANTS: Eight consecutive patients undergoing elective infrarenal abdominal aortic aneurysm repair. INTERVENTIONS: All patients received a standard anesthetic technique including a dopamine infusion (3 microg/kg/min) but without supplemental renoprotective agents. Urine and blood samples were taken at induction, at 1 hour and 3 hours after limb reperfusion, and on days 1 and 2 postoperatively. Urine microalbumin and creatinine concentrations were measured using standard assays, and urine pi-GST and alpha-GST enzyme measurements were performed by a commercial immunoassay (Biotrin, Biotrin International Ltd., Co., Dublin, Ireland). MEASUREMENTS AND MAIN RESULTS: Five patients (63%) showed a postoperative elevation of serum creatinine (median increase from baseline, 35.4%; range, 8.3% to 50.6%) that was associated with significant elevations of urinary microalbumin-to-creatinine, alpha-GST-to-creatinine, and pi-GST-to-creatinine ratios soon after clamp removal. The remaining 3 patients showed no increase in serum creatinine or urine proteins. Peak alpha-GST-to-creatinine levels were different between the 2 groups. The peak levels of GST enzymes were significantly (r(2) > 80%) associated with the percent increase in serum creatinine from baseline. CONCLUSION: Urinary GST-to-creatinine ratios are a sensitive early biomarker for renal injury after infrarenal abdominal aortic aneurysm repair.