Pre-operative optimisation for chronic obstructive pulmonary disease: a narrative review.

Chronic obstructive pulmonary disease is a condition commonly present in older people undergoing surgery and confers an increased risk of postoperative complications and mortality. Although predominantly a respiratory disease, it frequently has extra-pulmonary manifestations and typically occurs in the context of other long-term conditions. Patients experience a range of symptoms that affect their quality of life, functional ability and clinical outcomes. In this review, we discuss the evidence for techniques to optimise the care of people with chronic obstructive pulmonary disease in the peri-operative period, and address potential new interventions to improve outcomes. The article centres on pulmonary rehabilitation, widely available for the treatment of stable chronic obstructive pulmonary disease, but less often used in a peri-operative setting. Current evidence is largely at high risk of bias, however. Before surgery it is important to ensure that what have been called the 'five fundamentals' of chronic obstructive pulmonary disease treatment are achieved: smoking cessation; pulmonary rehabilitation; vaccination; self-management; and identification and optimisation of co-morbidities. Pharmacological treatment should also be optimised, and some patients may benefit from lung volume reduction surgery. Psychological and behavioural factors are important, but are currently poorly understood in the peri-operative period. Considerations of the risk and benefits of delaying surgery to ensure the recommended measures are delivered depends on patient characteristics and the nature and urgency of the planned intervention.

Pre-operative variables including fitness associated with complications after oesophagectomy.

Oesophagectomy is a technically-demanding operation associated with a high level of morbidity. We analysed the association of pre-operative variables, including those from cardiopulmonary exercise testing, with complications (logistic regression) and survival and length of stay (Cox regression) after scheduled transthoracic oesophagectomy in 273 adults, in isolation and on multivariate testing (maximum Akaike information criterion). On multivariate analysis, any postoperative complication was associated with ventilatory equivalents for carbon dioxide, odds ratio (95%CI) 1.088 (1.02-1.17), p = 0.018. Cardiorespiratory complications were associated with FEV1 and pre-operative background survival (in an analogous group without cancer), odds ratios (95%CI) 0.55 (0.37-0.80), p = 0.002 and 0.89 (0.82-0.96), p = 0.004, respectively. Survival was associated with the ratio of expected-to-observed ventilatory equivalents for carbon dioxide and predicted postoperative survival, hazard ratios (95%CI) 0.17 (0.03-0.91), p = 0.039 and 0.96 (0.90-1.01), p = 0.076. Length of hospital stay was associated with FVC, hazard ratio (95%CI) 1.38 (1.17-1.63), p < 0.0001.

Cardiopulmonary exercise testing before and after blood transfusion: a prospective clinical study.

BACKGROUND: Cardiopulmonary exercise testing (CPET) is used to risk-stratify patients undergoing major elective surgery, with a poor exercise capacity being associated with an increased risk of complications and death. Patients with anaemia have a decreased exercise capacity and an increased risk of morbidity and mortality after major surgery. Blood transfusion is often used to correct anaemia in the perioperative period but the effect of this intervention on exercise capacity is not well described. We sought to measure the effect of blood transfusion on exercise capacity measured objectively with CPET. METHODS: Patients with stable haematological conditions requiring blood transfusion underwent CPET before and 2-6 days after transfusion. RESULTS: Twenty patients were enrolled and completed both pre- and post-transfusion tests. The mean (sd) haemoglobin (Hb) concentration increased from 8.3 (1.2) to 11.2 (1.4) g dl(-1) after transfusion of a median (range) of 3 (1-4) units of packed red cells. The anaerobic threshold increased from a mean (sd) of 10.4 (2.4) to 11.6 (2.5) ml kg(-1) min(-1) (P=0.018), a mean difference of 1.2 ml kg(-1) min(-1) (95% confidence interval (CI)=0.2-2.2). When corrected for the change in Hb concentration, the anaerobic threshold increased by a mean (sd) of 0.39 (0.74) ml kg(-1) min(-1) per g dl(-1) Hb. CONCLUSIONS: Transfusion of allogeneic packed red cells in anaemic adults led to a significant increase in their capacity to exercise. This increase was seen in the anaerobic threshold, and other CPET variables.

Double bypass for inoperable pancreatic malignancy at laparotomy: postoperative complications and long-term outcome.

INTRODUCTION: Between 4% and 13% of patients with operable pancreatic malignancy are found unresectable at the time of surgery. Double bypass is a good option for fit patients but it is associated with a high risk of postoperative complications. The aim of this study was to identify pre-operatively which patients undergoing double bypass are at high risk of complications and to assess their long-term outcome. METHODS: Of the 576 patients undergoing pancreatic resections between 2006 and 2011, 50 patients who underwent a laparotomy for a planned pancreaticoduodenectomy had a double bypass procedure for inoperable disease. Demographic data, risk factors for postoperative complications and pre-operative anaesthetic assessment data including the Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (P-POSSUM) and cardiopulmonary exercise testing (CPET) were collected. RESULTS: Fifty patients (33 men and 17 women) were included in the study. The median patient age was 64 years (range: 39-79 years). The complication rate was 50% and the in-hospital mortality rate was 4%. The P-POSSUM physiology subscore and low anaerobic threshold at CPET were significantly associated with postoperative complications (p =0.005 and p =0.016 respectively) but they were unable to predict them. Overall long-term survival was significantly shorter in patients with postoperative complications (9 vs 18 months). Postoperative complications were independently associated with poorer long-term survival (p =0.003, odds ratio: 3.261). CONCLUSIONS: P-POSSUM and CPET are associated with postoperative complications but the possibility of using them for risk prediction requires further research. However, postoperative complications following double bypass have a significant impact on long-term survival and this type of surgery should therefore only be performed in specialised centres.

Effects of low cardiopulmonary reserve on pancreatic leak following pancreaticoduodenectomy.

BACKGROUND: Postoperative complications are increased in patients with reduced cardiopulmonary reserve undergoing major surgery. Pancreatic leak is an important contributor to postoperative complications and death following pancreaticoduodenectomy. The aim of this study was to determine whether reduced cardiopulmonary reserve was a risk factor for pancreatic leak. METHODS: All patients who underwent pancreaticoduodenectomy between January 2006 and July 2010 were identified from a prospectively held database. Data analysis was restricted to those who underwent cardiopulmonary exercise testing during preoperative assessment. Pancreatic leak was defined as grade A, B or C according to the International Study Group on Pancreatic Fistula definition. An anaerobic threshold (AT) cut-off value of 10·1 ml per kg per min was used to identify patients with reduced cardiopulmonary reserve. Univariable and multivariable analyses were performed to identify other risk factors for pancreatic leak. RESULTS: Some 67 men and 57 women with a median age of 66 (range 37-82) years were identified. Low AT was significantly associated with pancreatic leak (45 versus 19·2 per cent in patients with greater cardiopulmonary reserve; P = 0·020), postoperative complications (70 versus 38·5 per cent; P = 0·013) and prolonged hospital stay (29·4 versus 17·5 days; P = 0·001). On multivariable analysis, an AT of 10·1 ml per kg per min or less was the only independent factor associated with pancreatic leak. CONCLUSION: Low cardiopulmonary reserve was associated with pancreatic leak following pancreaticoduodenectomy. AT seems a useful tool for stratifying the risk of postoperative complications.

Decreasing delays in urgent and expedited surgery in a university teaching hospital through audit and communication between peri-operative and surgical directorates.

National Confidential Enquiry into Patient Outcome and Death guidelines for urgent surgery recommend a fully staffed emergency operating theatre and restriction of 'after-midnight' operating to immediate life-, limb- or organ-threatening conditions. Audit performed in our institution demonstrated significant decreases in waiting times for urgent surgery and an increased seniority of medical care associated with overnight pre-operative assessment of patients by anaesthetic trainees. Nevertheless, urgent cases continued to be delayed unnecessarily. A classification of delays was developed from existing guidelines and their incidence was audited. The results were disseminated to involved directorates. A repeat of the audit demonstrated a significant decrease in delays (p = 0.001), a significant increase in the availability of surgeons (p = 0.001) and a significant decrease in the median waiting time for urgent surgery compared to the first audit cycle and a previous standard (p < 0.01). We conclude that auditing delays and disseminating the results of the audit significantly decreases delays and median waiting times for urgent surgery because of improved surgical availability.

The use of N-terminal pro-B type natriuretic peptide in a pre-operative setting to predict left ventricular systolic dysfunction on echocardiogram.

Heart failure is a major risk factor for adverse postoperative events following non-cardiac surgery. The use of transthoracic echocardiogram as a pre-operative investigation to assess cardiac dysfunction has limitations in this setting. The N-Terminal fragment of B-Type natriuretic peptide (NT proBNP) has been used in screening for heart failure. We have investigated the use of NT proBNP as a screening tool for left ventricular systolic dysfunction to reduce the requirement for pre-operative echocardiograms. Ninety-eight pre-operative non-cardiac surgical patients scheduled to undergo echocardiography were assessed clinically and with an NT proBNP measurement. Echocardiogram was used to define two groups of patients depending on the presence or absence of abnormal left ventricular function and the NT proBNP level was compared between the groups using non-parametric and receiver-operator-characteristic (ROC) curve analysis. In terms of pre-operative screening, a NT proBNP of <38.2 pmol x l(-1) had a 100% negative predictive value in predicting patients with normal left ventricular systolic function and would have prevented the requirement for echocardiogram in 43% of pre-operative patients. NT proBNP was superior to electrocardiological and clinical criteria for detection of a normal echocardiogram. This may have significant impact in the pre-operative assessment of patients undergoing non-cardiac surgery.

Randomized clinical trial assessing the effect of Doppler-optimized fluid management on outcome after elective colorectal resection.

BACKGROUND: Protocolized fluid administration using oesophageal Doppler monitoring may improve the postoperative outcome in patients undergoing surgery. METHODS: A total of 108 patients undergoing elective colorectal resection were recruited into a double-blind prospective randomized controlled trial. An oesophageal Doppler probe was placed in all patients. The control group received perioperative fluid at the discretion of the anaesthetist, whereas the intervention group received additional colloid boluses based on Doppler assessment. Primary outcome was length of postoperative hospital stay. Secondary outcomes were morbidity, return of gastrointestinal function and cytokine markers of the systemic inflammatory response. Standard preoperative and postoperative management was used in all patients. RESULTS: Demographic and surgical details were similar in the two groups. Aortic flow time, stroke volume, cardiac output and cardiac index during the intraoperative period were higher in the intervention group (P<0.050). The intervention group had a reduced postoperative hospital stay (7 versus 9 days in the control group; P=0.005), fewer intermediate or major postoperative complications (2 versus 15 percent; P=0.043) and tolerated diet earlier (2 versus 4 days; P=0.029). There was a reduced rise in perioperative level of the cytokine interleukin 6 in the intervention group (P=0.039). CONCLUSION: A protocol-based fluid optimization programme using intraoperative oesophageal Doppler monitoring leads to a shorter hospital stay and decreased morbidity in patients undergoing elective colorectal resection.

Dopexamine and its role in the protection of hepatosplanchnic and renal perfusion in high-risk surgical and critically ill patients.

BACKGROUND: Dopexamine is increasingly being used in high-risk surgical and critically ill patients to preserve hepatosplanchnic and renal perfusion. This systematic review of randomized controlled trials was undertaken to investigate the clinical evidence for using dopexamine in this role. METHODS: Data sources included Medline, Cochrane Library, EMBASE and CINAHL and reference lists of relevant articles. Randomized controlled trials which compared dopexamine treatment with a control group, in high-risk surgical and critically ill adult patients and with primary outcome measures designed to assess hepatosplanchnic and renal perfusion were included. Articles not published in English were excluded. RESULTS: Twenty-one trials were selected from the literature search. The results suggest that dopexamine may protect against colonic mucosal damage in patients undergoing abdominal aortic surgery and may improve gastric mucosal pHi in general surgical patients, especially those with preoperative gastric mucosal pHi measurements <7.35 and those undergoing pancreatico-duodenectomy surgery. Dopexamine may have beneficial effects on renal perfusion in patients undergoing cardiac surgery but appears to have little or no benefit on gastric mucosal pHi in the same patient population. In critically ill patients none of the studies demonstrated a beneficial effect of dopexamine on either hepatosplanchnic or renal perfusion. CONCLUSION: The evidence provided by the existing studies is both inadequate and inconsistent. There is insufficient evidence to offer reliable recommendations on the clinical use of dopexamine for the protection of either hepatosplanchnic or renal perfusion in high-risk surgical patients. Furthermore, there is no current evidence to support a role for dopexamine in protecting either hepatosplanchnic or renal perfusion in critically ill patients.

Pulmonary edema in patients after liver transplantation.

The aim of this study is to determine the incidence of radiological pulmonary edema in elective liver transplant recipients and its relationship to perioperative factors and postoperative course. We reviewed 102 chest radiographs from 34 patients who had undergone orthotopic liver transplantation (OLT). Films were assessed by 2 trained radiologists for evidence of pulmonary edema using a standardized system. Clinical and outcome data from the 34 patients were also recorded. There was a high incidence (47%) of postoperative radiological pulmonary edema that was associated with deterioration in gaseous exchange, elevated pulmonary artery pressure, and increased duration of ventilator dependence and intensive care stay. Eighteen percent of the patients developed edema immediately after surgery, which was associated with greater pulmonary artery pressure and transfusion requirements during surgery. An additional 29% developed edema during the next 16 to 20 hours, but there was no association with fluid replacement. We conclude that pulmonary edema is common after OLT and will influence postoperative recovery in a substantial proportion of transplant recipients. Excess perioperative fluid replacement is unlikely to be the sole mechanism of edema in these patients.