Incidence and one year outcome of periprocedural myocardial infarction following cardiac surgery: are the universal definition and SCAI criteria fit for purpose?

Introduction

The diagnosis and clinical implication of periprocedural myocardial infarction (PPMI) following coronary artery bypass grafting (CABG) is contentious, especially given its importance in the interpretation of trial data. Two accepted definitions of PPMI yield discrepant results. Little is known about the association between the diagnosis of PPMI, using high sensitivity troponin (hs-cTn), and medium term mortality in patients who undergo CABG, either alone or in conjunction with another procedure. In addition, there are currently no criteria for the diagnosis of PPMI following non-CABG surgery.

Method

Consecutive patients admitted to a cardiothoracic critical care unit (CCCU) over a six month period following open cardiac surgery had hs-cTnI assay performed on admission and every day for forty-eight hours, regardless of whether there was a clinical indication. Patients were categorised as PPMI using both the Universal Definition of MI (UDMI) and Society of Cardiovascular Angiography and Interventions (SCAI) criteria. Comorbidity data, surgical details and clinical progress in CCCU were recorded. One year mortality data were obtained from NHS Digital.

Results

There were 245 CABG patients, of whom 20.4% met criteria for UDMI PPMI and 87.6% for SCAI UDMI (figure 1). The diagnosis of UDMI PPMI was independently associated with one year mortality (hazard ratio 4.175 (95% confidence interval 1.281 – 13.608)), whereas there was no association between SCAI PPMI and one year mortality (figure 2). Of the 243 patients who had non CABG cardiac surgery, 11.4% met criteria for UDMI PPMI and 85.2% for SCAI PPMI (figure1) but neither was associated with one year mortality.

Conclusions

The incidence of SCAI PPMI in a real world cohort of cardiac surgery patients is so high as to be of limited clinical value. By contrast, a diagnosis of UDMI PPMI post CABG is independently associated with one year mortality, so may have clinical utility.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Beckman Coulter - supplied the assays used in the study but had no role in the study Figure 1. Frequency of PPMIFigure 2. Kaplan Meier curves

The relationship between high-sensitivity troponin taken on admission to critical care, regardless of whether there was a clinical indication for testing, and one year mortality

Introduction

High-sensitivity troponin (hs-cTn) assays now form a key component of the diagnostic pathways for patients presenting to emergency medical services with chest pain. However, hs-cTn concentrations above the manufacturer-provided upper limit of normal (ULN) are now frequently reported in patients presenting with conditions not traditionally associated with type 1 myocardial infarction (T1MI). This is particularly true of severe illness states. We investigated the possible association between hs-cTn and 1 year mortality in critical care patients.

Method

Consecutive patients admitted to two adult critical care units (general critical care unit (GCCU) and neuroscience critical care unit (NCCU)) over a six month period had hs-cTnI assay performed on admission, regardless of whether there was a clinical indication, and the results nested unless a clinical request had been made. Comorbidity data, illness severity and critical care outcome were recorded and have been previously reported. One year mortality data were obtained from NHS Digital.

Results

After excluding patients diagnosed with T1MI by the clinical team, there were 1,033 patients remaining. At one year a total of 253 (24.5%) patients had died. The Kaplan-Meier curves in figure 1 demonstrate a positive association between mortality and increasing hs-cTnI concentrations relative to the ULN. Specifically, using the log-rank test, the mortality at one year was significantly higher (p<0.001) in patients with hs-cTnI concentrations above the ULN. Furthermore, on multivariable Cox regression analysis, the log(10) hs-cTnI concentration was independently associated with the hazard of one year mortality (hazard ratio 1.587 (95% confidence interval 1.358–1.856).

Conclusions

These data suggest that admission hs-cTnI is a biomarker for one year mortality in critical care patients. Further work is now required to assess whether any medical intervention can alter this risk.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Beckman Coulter provided the assays for the tests used in this study. They had no other involvement in the study

Development and evaluation of a novel pre-operative surgery school and behavioural change intervention for patients undergoing elective major surgery: Fit-4-Surgery School

Group pre-operative education has usually been limited to conditioning expectations and providing education. Prehabilitation has highlighted modifiable lifestyle factors that are amenable to change and may improve clinical outcomes. We instituted a pre-operative 'Fit-4-Surgery School' for patients scheduled for major surgery, to educate and promote healthy behaviour. We evaluated patients' views having attended the school, and after surgery we asked how it had changed their behaviour with a lifestyle questionnaire. The school was launched in May 2016 and was attended by 586/1017 (58%) of invited patients. Patients who did not attend: lived further away, median (IQR [range]) 8 (4-19 [0-123]) miles vs. 5 (3-14 [0-172]) miles, p < 0.001; and were more deprived, Index of Multiple Deprivation Rank decile median (IQR [range]), 6 (4-8 [1-10]) vs. 7 (4-9 [1-10]), p = 0.04. Of the 492/586 (84%) participants who completed an evaluation questionnaire, 462 (94%) would recommend the school to a friend having surgery and 296 (60%) planned lifestyle changes. After surgery, 232/586 (40%) completed a behavioural change questionnaire, 106 (46%) of whom reported changing at least one lifestyle factor, most commonly by increasing exercise. The pre-operative school was acceptable to patients.

Why women are not small men: sex-related differences in perioperative cardiopulmonary exercise testing

Background

The use of preoperative cardiopulmonary exercise testing (CPET) to evaluate the risk of adverse perioperative outcomes is increasingly prevalent. CPET-derived information enables personalised perioperative care and enhances shared decision-making. Sex-related differences in physical fitness are reported in non-perioperative literature. However, little attention has been paid to sex-related differences in the context of perioperative CPET.

Aim

We explored differences in the physical fitness variables reported in a recently published multi-centre study investigating CPET before colorectal surgery. We also report the inclusion rate of females in published perioperative CPET cohorts that are shaping guidelines and clinical practice.

Methods

We performed a post hoc analysis of the trial data of 703 patients who underwent CPET prior to major elective colorectal surgery. We also summarised the female inclusion rate in peer-reviewed published reports of perioperative CPET.

Results

Fitness assessed using commonly used perioperative CPET variables—oxygen consumption at anaerobic threshold (AT) and peak exercise—was significantly higher in males than in females both before and after correction for body weight. In studies contributing to the development of perioperative CPET, 68.5% of the participants were male.

Conclusion

To our knowledge, this is the first study to describe differences between males and females in CPET variables used in a perioperative setting. Furthermore, there is a substantial difference between the inclusion rates of males and females in this field. These findings require validation in larger cohorts and may have significant implications for both sexes in the application of CPET in the perioperative setting.

Hospital-level evaluation of the effect of a national quality improvement programme: time-series analysis of registry data

BACKGROUND AND OBJECTIVES

A clinical trial in 93 National Health Service hospitals evaluated a quality improvement programme for emergency abdominal surgery, designed to improve mortality by improving the patient care pathway. Large variation was observed in implementation approaches, and the main trial result showed no mortality reduction. Our objective therefore was to evaluate whether trial participation led to care pathway implementation and to study the relationship between care pathway implementation and use of six recommended implementation strategies.

METHODS

We performed a hospital-level time-series analysis using data from the Enhanced Peri-Operative Care for High-risk patients trial. Care pathway implementation was defined as achievement of >80% median reliability in 10 measured care processes. Mean monthly process performance was plotted on run charts. Process improvement was defined as an observed run chart signal, using probability-based 'shift' and 'runs' rules. A new median performance level was calculated after an observed signal.

RESULTS

Of 93 participating hospitals, 80 provided sufficient data for analysis, generating 800 process measure charts from 20 305 patient admissions over 27 months. No hospital reliably implemented all 10 processes. Overall, only 279 of the 800 processes were improved (3 (2-5) per hospital) and 14/80 hospitals improved more than six processes. Mortality risk documented (57/80 (71%)), lactate measurement (42/80 (53%)) and cardiac output guided fluid therapy (32/80 (40%)) were most frequently improved. Consultant-led decision making (14/80 (18%)), consultant review before surgery (17/80 (21%)) and time to surgery (14/80 (18%)) were least frequently improved. In hospitals using ≥5 implementation strategies, 9/30 (30%) hospitals improved ≥6 care processes compared with 0/11 hospitals using ≤2 implementation strategies.

CONCLUSION

Only a small number of hospitals improved more than half of the measured care processes, more often when at least five of six implementation strategies were used. In a longer term project, this understanding may have allowed us to adapt the intervention to be effective in more hospitals.

Cohort study of preoperative blood pressure and risk of 30-day mortality after elective non-cardiac surgery

Background

Preoperative blood pressure (BP) thresholds associated with increased postoperative mortality remain unclear. We investigated the relationship between preoperative BP and 30-day mortality after elective non-cardiac surgery.

Methods

We performed a cohort study of primary care data from the UK Clinical Practice Research Datalink (2004-13). Parsimonious and fully adjusted multivariable logistic regression models, including restricted cubic splines for numerical systolic and diastolic BP, for 30-day mortality were constructed. The full model included 29 perioperative risk factors, including age, sex, comorbidities, medications, and surgical risk scale. Sensitivity analyses were conducted for age (>65 vs <65 years old) and the timing of BP measurement.

Results

A total of 251 567 adults were included, with 589 (0.23%) deaths within 30 days of surgery. After adjustment for all risk factors, preoperative low BP was consistently associated with statistically significant increases in the odds ratio (OR) of postoperative mortality. Statistically significant risk thresholds started at a preoperative systolic pressure of 119 mm Hg (adjusted OR 1.02 [95% confidence interval (CI) 1.01-1.02]) compared with the reference (120 mm Hg) and diastolic pressure of 63 mm Hg [OR 1.24 (95% CI 1.03-1.49)] compared with the reference (80 mm Hg). As BP decreased, the OR of mortality risk increased. Subgroup analysis demonstrated that the risk associated with low BP was confined to the elderly. Adjusted analyses identified that diastolic hypertension was associated with increased postoperative mortality in the whole cohort.

Conclusions

In this large observational study we identified a significant dose-dependent association between low preoperative BP values and increased postoperative mortality in the elderly. In the whole population, elevated diastolic, not systolic, BP was associated with increased mortality.

Total haemoglobin mass, but not haemoglobin concentration, is associated with preoperative cardiopulmonary exercise testing-derived oxygen-consumption variables

Background

Cardiopulmonary exercise testing (CPET) measures peak exertional oxygen consumption ( V˙O2peak ) and that at the anaerobic threshold ( V˙O2 at AT, i.e. the point at which anaerobic metabolism contributes substantially to overall metabolism). Lower values are associated with excess postoperative morbidity and mortality. A reduced haemoglobin concentration ([Hb]) results from a reduction in total haemoglobin mass (tHb-mass) or an increase in plasma volume. Thus, tHb-mass might be a more useful measure of oxygen-carrying capacity and might correlate better with CPET-derived fitness measures in preoperative patients than does circulating [Hb].

Methods

Before major elective surgery, CPET was performed, and both tHb-mass (optimized carbon monoxide rebreathing method) and circulating [Hb] were determined.

Results

In 42 patients (83% male), [Hb] was unrelated to V˙O2 at AT and V˙O2peak ( r =0.02, P =0.89 and r =0.04, P =0.80, respectively) and explained none of the variance in either measure. In contrast, tHb-mass was related to both ( r =0.661, P <0.0001 and r =0.483, P =0.001 for V˙O2 at AT and V˙O2peak , respectively). The tHb-mass explained 44% of variance in V˙O2 at AT ( P <0.0001) and 23% in V˙O2peak ( P =0.001).

Conclusions

In contrast to [Hb], tHb-mass is an important determinant of physical fitness before major elective surgery. Further studies should determine whether low tHb-mass is predictive of poor outcome and whether targeted increases in tHb-mass might thus improve outcome.

Replicating measurements of total hemoglobin mass (tHb-mass) within a single day: precision of measurement; feasibility and safety of using oxygen to expedite carbon monoxide clearance

Hemoglobin concentration ([Hb]) is a function of total hemoglobin mass (tHb-mass) and plasma volume. [Hb] may fall by dilution due to plasma volume expansion and changes in the perioperative period may therefore correlate poorly with blood loss. A simple, reliable, repeatable way to measure plasma volume and tHb-mass would have substantial clinical utility. The "optimized carbon monoxide re-breathing method" (oCOR) meets these criteria. However, it is recommended that a minimum of 12 h (when breathing room air) is left between repeat measurements. Twenty-four subjects underwent 3 days of testing. Two oCOR tests were performed (T1 and T2), 3 h apart, with a different CO clearance method employed between tests aiming to keep the carboxyhemoglobin level below 10%. The primary aim was to ascertain whether tHb-mass testing could be safely repeated within 3 h if carboxyhemoglobin levels were actively reduced by breathing supplemental oxygen (PROCA ). Secondary aims were to compare two other clearance methods; moderate exercise (PROCB ), or a combination of the two (PROCC ). Finally, the reliability of the oCOR method was assessed. Mean (SD) tHb-mass was 807.9 ± (189.7 g) (for T1 on day 1). PROCA lowered the carboxyhemoglobin level from the end of T1 (mean 6.64%) to the start of T2 (mean 2.95%) by a mean absolute value of 3.69%. For PROCB and PROCC the mean absolute decreases in carboxyhemoglobin were 4.00% and 4.31%, respectively. The fall in carboxyhemoglobin between T1 and T2 was greatest in PROCC ; this was statistically significantly lower than that of PROCA (P = 0.0039) and PROCB (P = 0.0289). The test-retest reliability for the measurement of total hemoglobin mass was good with a mean typical error (TE) of 2.0%. The oCOR method is safe and can be repeated within 3 h when carbon monoxide is suitably cleared between tests. Using oxygen therapy alone adequately achieves this.

Patient reported outcome of adult perioperative anaesthesia in the United Kingdom: a cross-sectional observational study

BACKGROUND

Understanding the patient perspective on healthcare is central to the evaluation of quality. This study measured selected patient-reported outcomes after anaesthesia in order to identify targets for research and quality improvement.

METHODS

This cross-sectional observational study in UK National Health Service hospitals, recruited adults undergoing non-obstetric surgery requiring anaesthesia care over a 48 h period. Within 24 h of surgery, patients completed the Bauer questionnaire (measuring postoperative discomfort and satisfaction with anaesthesia care), and a modified Brice questionnaire to elicit symptoms suggestive of accidental awareness during general anaesthesia (AAGA). Patient, procedural and pharmacological data were recorded to enable exploration of risk factors for these poor outcomes.

RESULTS

257 hospitals in 171 NHS Trusts participated (97% of eligible organisations). Baseline characteristics were collected on 16,222 patients; 15,040 (93%) completed postoperative questionnaires. Anxiety was most frequently cited as the worst aspect of the perioperative experience. Thirty-five per cent of patients reported severe discomfort in at least one domain: thirst (18.5%; 95% CI 17.8-19.1), surgical pain (11.0%; 10.5-11.5) and drowsiness (10.1%; 9.6-10.5) were most common. Despite this, only 5% reported dissatisfaction with any aspect of anaesthesia-related care. Regional anaesthesia was associated with a reduced burden of side-effects. The incidence of reported AAGA was one in 800 general anaesthetics (0.12%)

CONCLUSIONS

Anxiety and discomfort after surgery are common; despite this, satisfaction with anaesthesia care in the UK is high. The inconsistent relationship between patient-reported outcome, patient experience and patient satisfaction supports using all three of these domains to provide a comprehensive assessment of the quality of anaesthesia care.

A systematic review of the safety and efficacy of aerobic exercise during cytotoxic chemotherapy treatment

PURPOSE

Aerobic exercise improves prognosis and quality of life (QoL) following completion of chemotherapy. However, the safety and efficacy of aerobic exercise during chemotherapy is less certain. A systematic review was performed of randomised trials of adult patients undergoing chemotherapy, comparing an exercise intervention with standard care.

METHOD

From 253 abstracts screened, 33 unique trials were appraised in accordance with PRISMA guidance, including 3257 patients. Interventions included walking, jogging or cycling, and 23 were of moderate intensity (50-80% maximum heart rate).

RESULTS

Aerobic exercise improved, or at least maintained fitness during chemotherapy. Moderately intense exercise, up to 70-80% of maximum heart rate, was safe. Any reported adverse effects of exercise were mild and self-limiting, but reporting was inconsistent. Adherence was good (median 72%). Exercise improved QoL and physical functioning, with earlier return to work. Two out of four studies reported improved chemotherapy completion rates. Four out of six studies reported reduced chemotherapy toxicity. There was no evidence that exercise reduced myelosuppression or improved response rate or survival.

CONCLUSIONS

Exercise during chemotherapy is safe and should be encouraged because of beneficial effects on QoL and physical functioning. More research is required to determine the impact on chemotherapy completion rates and prognosis.

The future of UK healthcare: problems and potential solutions to a system in crisis

The UK's Health System is in crisis, central funding no longer keeping pace with demand. Traditional responses-spending more, seeking efficiency savings or invoking market forces-are not solutions. The health of our nation demands urgent delivery of a radical new model, negotiated openly between public, policymakers and healthcare professionals. Such a model could focus on disease prevention, modifying health behaviour and implementing change in public policy in fields traditionally considered unrelated to health such as transport, food and advertising. The true cost-effectiveness of healthcare interventions must be balanced against the opportunity cost of their implementation, bolstering the central role of NICE in such decisions. Without such action, the prognosis for our healthcare system-and for the health of the individuals it serves-may be poor. Here, we explore such a new prescription for our national health.

Inter-observer reliability of preoperative cardiopulmonary exercise test interpretation: a cross-sectional study

BACKGROUND

Despite the increasing importance of cardiopulmonary exercise testing (CPET) for preoperative risk assessment, the reliability of CPET interpretation is unclear. We aimed to assess inter-observer reliability of preoperative CPET.

METHODS

We conducted a prospective, multi-centre, observational study of preoperative CPET interpretation. Participants were professionals with previous experience or training in CPET, assessed by a standardized questionnaire. Each participant interpreted 100 tests using standardized software. The CPET variables of interest were oxygen consumption at the anaerobic threshold (AT) and peak oxygen consumption (VO₂ peak). Inter-observer reliability was measured using intra-class correlation coefficient (ICC) with a random effects model. Results are presented as ICC with 95% confidence interval, where ICC of 1 represents perfect agreement and ICC of 0 represents no agreement.

RESULTS

Participants included 8/28 (28.6%) clinical physiologists, 10 (35.7%) junior doctors, and 10 (35.7%) consultant doctors. The median previous experience was 140 (inter-quartile range 55-700) CPETs. After excluding the first 10 tests (acclimatization) for each participant and missing data, the primary analysis of AT and VO₂ peak included 2125 and 2414 tests, respectively. Inter-observer agreement for numerical values of AT [ICC 0.83 (0.75-0.90)] and VO₂ peak [ICC 0.88 (0.84-0.92)] was good. In a post hoc analysis, inter-observer agreement for identification of the presence of a reportable AT was excellent [ICC 0.93 (0.91-0.95)] and a reportable VO₂ peak was moderate [0.73 (0.64-0.80)].

CONCLUSIONS

Inter-observer reliability of interpretation of numerical values of two commonly used CPET variables was good (>80%). However, inter-observer agreement regarding the presence of a reportable value was less consistent.

Transfusion in critical care - a UK regional audit of current practice

A consistent message within critical care publications has been that a restrictive transfusion strategy is non-inferior, and possibly superior, to a liberal strategy for stable, non-bleeding critically ill patients. Translation into clinical practice has, however, been slow. Here, we describe the degree of adherence to UK best practice guidelines in a regional network of nine intensive care units within Wessex. All transfusions given during a 2-month period were included (n = 444). Those given for active bleeding or within 24 h of major surgery, trauma or gastrointestinal bleeding were excluded (n = 148). The median (IQR [range]) haemoglobin concentration before transfusion was 73 (68-77 [53-106]) g.l^-1 , with only 34% of transfusion episodes using a transfusion threshold of < 70 g.l^-1 . In a subgroup analysis that did not study patients with a history of cardiac disease (n = 42), haemoglobin concentration before transfusion was 72 (68-77 [50-98]) g.l^-1 , with only 36% of transfusion episodes using a threshold of < 70 g.l^-1 (see Fig. 3). Most blood transfusions given to critically ill patients who were not bleeding in this audit used a haemoglobin threshold > 70 g.l^-1 . The reason why recommendations on transfusion triggers have not translated into clinical practice is unclear. With a clear national drive to decrease usage of blood products and clear evidence that a threshold of 70 g.l^-1 is non-inferior, it is surprising that a scarce and potentially dangerous resource is still being overused within critical care. Simple solutions such as electronic patient records that force pause for thought before blood transfusion, or prescriptions that only allow administration of a single unit in non-emergency circumstances may help to reduce the incidence of unnecessary blood transfusions.

The effect of neoadjuvant chemotherapy and chemoradiotherapy on exercise capacity and outcome following upper gastrointestinal cancer surgery: an observational cohort study

Background

In 2014 approximately 21,200 patients were diagnosed with oesophageal and gastric cancer in England and Wales, of whom 37 % underwent planned curative treatments. Potentially curative surgical resection is associated with significant morbidity and mortality. For operable locally advanced disease, neoadjuvant chemotherapy (NAC) improves survival over surgery alone. However, NAC carries the risk of toxicity and is associated with a decrease in physical fitness, which may in turn influence subsequent clinical outcome. Lower levels of physical fitness are associated with worse outcome following major surgery in general and Upper Gastrointestinal Surgery (UGI) surgery in particular. Cardiopulmonary exercise testing (CPET) provides an objective assessment of physical fitness. The aim of this study is to test the hypothesis that NAC prior to upper gastrointestinal cancer surgery is associated with a decrease in physical fitness and that the magnitude of the change in physical fitness will predict mortality 1 year following surgery.

Methods

This study is a multi-centre, prospective, blinded, observational cohort study of participants with oesophageal and gastric cancer scheduled for neoadjuvant cancer treatment (chemo- and chemoradiotherapy) and surgery. The primary endpoints are physical fitness (oxygen uptake at lactate threshold measured using CPET) and 1-year mortality following surgery; secondary endpoints include post-operative morbidity (Post-Operative Morbidity Survey (POMS)) 5 days after surgery and patient related quality of life (EQ-5D-5 L).

Discussion

The principal benefits of this study, if the underlying hypothesis is correct, will be to facilitate better selection of treatments (e.g. NAC, Surgery) in patients with oesophageal or gastric cancer. It may also be possible to develop new treatments to reduce the effects of neoadjuvant cancer treatment on physical fitness. These results will contribute to the design of a large, multi-centre trial to determine whether an in-hospital exercise-training programme that increases physical fitness leads to improved overall survival.

Trial registration

ClinicalTrials.gov NCT01325883 - 29^th March 2011.

Validation of preoperative cardiopulmonary exercise testing-derived variables to predict in-hospital morbidity after major colorectal surgery

BACKGROUND

In single-centre studies, postoperative complications are associated with reduced fitness. This study explored the relationship between cardiorespiratory fitness variables derived by cardiopulmonary exercise testing (CPET) and in-hospital morbidity after major elective colorectal surgery.

METHODS

Patients underwent preoperative CPET with recording of in-hospital morbidity. Receiver operating characteristic (ROC) curves and logistic regression were used to assess the relationship between CPET variables and postoperative morbidity.

RESULTS

Seven hundred and three patients from six centres in the UK were available for analysis (428 men, 275 women). ROC curve analysis of oxygen uptake at estimated lactate threshold (V˙o₂ at θ^_L ) and at peak exercise (V˙o_2peak ) gave an area under the ROC curve (AUROC) of 0·79 (95 per cent c.i. 0·76 to 0·83; P < 0·001; cut-off 11·1 ml per kg per min) and 0·77 (0·72 to 0·82; P < 0·001; cut-off 18·2 ml per kg per min) respectively, indicating that they can identify patients at risk of postoperative morbidity. In a multivariable logistic regression model, selected CPET variables and body mass index (BMI) were associated significantly with increased odds of in-hospital morbidity (V˙o₂ at θ^_L 11·1 ml per kg per min or less: odds ratio (OR) 7·56, 95 per cent c.i. 4·44 to 12·86, P < 0·001; V˙o_2peak 18·2 ml per kg per min or less: OR 2·15, 1·01 to 4·57, P = 0·047; ventilatory equivalents for carbon dioxide at estimated lactate threshold (V˙_E /V˙co₂ at θ^_L ) more than 30·9: OR 1·38, 1·00 to 1·89, P = 0·047); BMI exceeding 27 kg/m² : OR 1·05, 1·03 to 1·08, P < 0·001). A laparoscopic procedure was associated with a decreased odds of complications (OR 0·30, 0·02 to 0·44; P = 0·033). This model was able to discriminate between patients with, and without in-hospital morbidity (AUROC 0·83, 95 per cent c.i. 0·79 to 0·87). No adverse clinical events occurred during CPET across the six centres.

CONCLUSION

These data provide further evidence that variables derived from preoperative CPET can be used to assess risk before elective colorectal surgery.

Timing of surgery following neoadjuvant chemoradiotherapy in locally advanced rectal cancer - A comparison of magnetic resonance imaging at two time points and histopathological responses

PURPOSE

There is wide inter-institutional variation in the interval between neoadjuvant chemoradiotherapy (NACRT) and surgery for locally advanced rectal cancer. We aimed to assess the association of magnetic resonance imaging (MRI) at 9 and 14 weeks post-NACRT; T-staging (ymrT) and post-NACRT tumour regression grading (ymrTRG) with histopathological outcomes; histopathological T-stage (ypT) and histopathological tumour regression grading (ypTRG) in order to inform decision-making about timing of surgery.

PATIENTS AND METHODS

We prospectively studied 35 consecutive patients (26 males) with MRI-defined resection margin threatened rectal cancer who had completed standardized NACRT. Patients underwent a MRI at Weeks 9 and 14 post-NACRT, and surgery at Week 15. Two readers independently assessed MRIs for ymrT, ymrTRG and volume change. ymrT and ymrTRG were analysed against histopathological ypT and ypTRG as predictors by logistic regression modelling and receiver operating characteristic (ROC) curve analyses.

RESULTS

Thirty-five patients were recruited. Inter-observer agreement was good for all MR variables (Kappa > 0.61). Considering ypT as an outcome variable, a stronger association of favourable ymrTRG and volume change at Week 14 compared to Week 9 was found (ymrTRG - p = 0.064 vs. p = 0.010; Volume change - p = 0.062 vs. p = 0.007). Similarly, considering ypTRG as an outcome variable, a greater association of favourable ymrTRG and volume change at Week 14 compared to Week 9 was found (ymrTRG - p = 0.005 vs. p = 0.042; Volume change - p = 0.004 vs. 0.055).

CONCLUSION

Following NACRT, greater tumour down-staging and volume reduction was observed at Week 14. Timing of surgery, in relation to NACRT, merits further investigation.

TRIAL REGISTRATION NUMBER

NCT01325909.

Mortality of emergency general surgical patients and associations with hospital structures and processes

BACKGROUND

Variations in patient outcomes between providers have been described for emergency admissions, including general surgery. The aim of this study was to investigate whether differences in modifiable hospital structures and processes were associated with variance in mortality, amongst patients admitted for emergency colorectal laparotomy, peptic ulcer surgery, appendicectomy, hernia repair and pancreatitis.

METHODS

Adult emergency admissions in the English NHS were extracted from the Hospital Episode Statistics between April 2005 and March 2010. The association between mortality and structure and process measures including medical and nursing staffing levels, critical care and operating theatre availability, radiology utilization, teaching hospital status and weekend admissions were investigated.

RESULTS

There were 294 602 emergency admissions to 156 NHS Trusts (hospital systems) with a 30-day mortality of 4.2%. Trust-level mortality rates for this cohort ranged from 1.6 to 8.0%. The lowest mortality rates were observed in Trusts with higher levels of medical and nursing staffing, and a greater number of operating theatres and critical care beds relative to provider size. Higher mortality rates were seen in patients admitted to hospital at weekends [OR 1.11 (95% CI 1.06-1.17) P<0.0001], in Trusts with fewer general surgical doctors [1.07 (1.01-1.13) P=0.019] and with lower nursing staff ratios [1.07 (1.01-1.13) P=0.024].

CONCLUSIONS

Significant differences between Trusts were identified in staffing and other infrastructure resources for patients admitted with an emergency general surgical diagnosis. Associations between these factors and mortality rates suggest that potentially modifiable factors exist that relate to patient outcomes, and warrant further investigation.

Validation of preoperative cardiopulmonary exercise testing-derived variables to predict in-hospital morbidity after major colorectal surgery

BACKGROUND

In single-centre studies, postoperative complications are associated with reduced fitness. This study explored the relationship between cardiorespiratory fitness variables derived by cardiopulmonary exercise testing (CPET) and in-hospital morbidity after major elective colorectal surgery.

METHODS

Patients underwent preoperative CPET with recording of in-hospital morbidity. Receiver operating characteristic (ROC) curves and logistic regression were used to assess the relationship between CPET variables and postoperative morbidity.

RESULTS

Seven hundred and three patients from six centres in the UK were available for analysis (428 men, 275 women). ROC curve analysis of oxygen uptake at estimated lactate threshold (V˙o₂ at θ^_L ) and at peak exercise (V˙o_2peak ) gave an area under the ROC curve (AUROC) of 0·79 (95 per cent c.i. 0·76 to 0·83; P < 0·001; cut-off 11·1 ml per kg per min) and 0·77 (0·72 to 0·82; P < 0·001; cut-off 18·2 ml per kg per min) respectively, indicating that they can identify patients at risk of postoperative morbidity. In a multivariable logistic regression model, selected CPET variables and body mass index (BMI) were associated significantly with increased odds of in-hospital morbidity (V˙o₂ at θ^_L 11·1 ml per kg per min or less: odds ratio (OR) 7·56, 95 per cent c.i. 4·44 to 12·86, P < 0·001; V˙o_2peak 18·2 ml per kg per min or less: OR 2·15, 1·01 to 4·57, P = 0·047; ventilatory equivalents for carbon dioxide at estimated lactate threshold (V˙_E /V˙co₂ at θ^_L ) more than 30·9: OR 1·38, 1·00 to 1·89, P = 0·047); BMI exceeding 27 kg/m² : OR 1·05, 1·03 to 1·08, P < 0·001). A laparoscopic procedure was associated with a decreased odds of complications (OR 0·30, 0·02 to 0·44; P = 0·033). This model was able to discriminate between patients with, and without in-hospital morbidity (AUROC 0·83, 95 per cent c.i. 0·79 to 0·87). No adverse clinical events occurred during CPET across the six centres.

CONCLUSION

These data provide further evidence that variables derived from preoperative CPET can be used to assess risk before elective colorectal surgery.

Risk assessment tools validated for patients undergoing emergency laparotomy: a systematic review

Emergency laparotomies are performed commonly throughout the world, but one in six patients die within a month of surgery. Current international initiatives to reduce the considerable associated morbidity and mortality are founded upon delivering individualised perioperative care. However, while the identification of high-risk patients requires the routine assessment of individual risk, no method of doing so has been demonstrated to be practical and reliable across the commonly encountered spectrum of presentations, co-morbidities and operative procedures. A systematic review of Embase and Medline identified 20 validation studies assessing 25 risk assessment tools in patients undergoing emergency laparotomy. The most frequently studied general tools were APACHE II, ASA-PS and P-POSSUM. Comparative, quantitative analysis of tool performance was not feasible due to the heterogeneity of study design, poor reporting and infrequent within-study statistical comparison of tool performance. Reporting of calibration was notably absent in many prognostic tool validation studies. APACHE II demonstrated the most consistent discrimination of individual outcome across a variety of patient groups undergoing emergency laparotomy when used either preoperatively or postoperatively (area under the curve 0.76-0.98). While APACHE systems were designed for use in critical care, the ability of APACHE II to generate individual risk estimates from objective, exclusively preoperative data items may lead to better-informed shared decisions, triage and perioperative management of patients undergoing emergency laparotomy. Future endeavours should include the recalibration of APACHE II and P-POSSUM in contemporary cohorts, modifications to enable prediction of morbidity and assessment of the impact of adoption of these tools on clinical practice and patient outcomes.

Exercise intervention in people with cancer undergoing neoadjuvant cancer treatment and surgery: A systematic review

BACKGROUND

Neoadjuvant cancer treatment decreases physical fitness. Low levels of physical fitness are associated with poor surgical outcome. Exercise training can stimulate skeletal muscle adaptations, such as increased mitochondrial content and improved oxygen uptake capacity that may contribute to improving physical fitness. This systematic review evaluates the evidence in support of exercise training in people with cancer undergoing the "dual hit" of neoadjuvant cancer treatment and surgery.

METHODS

We conducted a systematic database search of Embase Ovid, Ovid Medline without Revisions, SPORTDiscus, Web of Science, Cochrane Central Register of Controlled Trials Library and ClinicalTrials.gov to identify trials addressing the effect of exercise training in people scheduled for neoadjuvant cancer treatment and surgery. Data extraction and analysis were based on a pre-defined plan.

RESULTS

The database search yielded 6489 candidate abstracts. Ninety-four references included the required terms. Four studies were eligible for inclusion (breast cancer, locally advanced rectal cancer). All studies reported that exercise training was safe and feasible and that adherence rates were acceptable (66-96%). In-hospital exercise training improves physical fitness however the impact on HRQoL and other clinical important outcomes was uncertain.

CONCLUSION

This is the first systematic review of the effects of exercise training in people scheduled for "dual-hit" treatment. This evidence synthesis indicates that this approach is safe and feasible but that there are insufficient controlled trials in this area to draw reliable conclusions about the efficacy of such an intervention, the optimal characteristics of the intervention, or the impact on clinical or patient reported outcomes.

Exercise intervention in people with cancer undergoing adjuvant cancer treatment following surgery: A systematic review

BACKGROUND

Remaining physically active during and after cancer treatment is known to improve associated adverse effects, improve overall survival and reduce the probability of relapse. This systematic review addresses the question: is an exercise training programme beneficial in people with cancer undergoing adjuvant cancer treatment following surgery.

METHODS

A systematic database search of Embase, Ovid, Medline without Revisions, SPORTDiscus, Web of Science, Cochrane Library and ClinicalTrials.gov for any randomised controlled trials (RCT) or non-RCT addressing the effect of an exercise training programme in those having adjuvant cancer treatment following surgery was conducted.

RESULTS

The database search yielded 6489 candidate abstracts of which 94 references included the required terms. A total of 17 articles were included in this review. Exercise training is safe and feasible in the adjuvant setting and furthermore may improve measures of physical fitness and health related quality of life (HRQoL).

CONCLUSION

This is the first systematic review on exercise training interventions in people with cancer undergoing adjuvant cancer treatment following surgery. Due to the lack of adequately powered RCTs in this area, it remains unclear whether exercise training in this context improves clinical outcomes other physical fitness and HRQoL. It remains unclear what is the optimal timing of initiation of an exercise programme and what are the best combinations of elements within an exercise training programme to optimise training efficacy. Furthermore, it is unclear if initiating such exercise programmes at cancer diagnosis may have a long-lasting effect on physically activity throughout the subsequent life course.

Systemic oxygen extraction during exercise at high altitude

Background

Classic teaching suggests that diminished availability of oxygen leads to increased tissue oxygen extraction yet evidence to support this notion in the context of hypoxaemia, as opposed to anaemia or cardiac failure, is limited.

Methods

At 75 m above sea level, and after 7–8 days of acclimatization to 4559 m, systemic oxygen extraction [C(a−v)O₂] was calculated in five participants at rest and at peak exercise. Absolute [C(a−v)O₂] was calculated by subtracting central venous oxygen content (CcvO₂) from arterial oxygen content (CaO2) in blood sampled from central venous and peripheral arterial catheters, respectively. Oxygen uptake (V˙O2) was determined from expired gas analysis during exercise.

Results

Ascent to altitude resulted in significant hypoxaemia; median (range) SpO2 87.1 (82.5–90.7)% and PaO2 6.6 (5.7–6.8) kPa. While absolute C(a−v)O₂ was reduced at maximum exercise at 4559 m [83.9 (67.5–120.9) ml litre⁻¹vs 99.6 (88.0–151.3) ml litre⁻¹ at 75 m, P=0.043], there was no change in oxygen extraction ratio (OER) [C(a−v)O₂/CaO₂] between the two altitudes [0.52 (0.48–0.71) at 4559 m and 0.53 (0.49–0.73) at 75 m, P=0.500]. Comparison of C(a−v)O₂ at peak V˙O2 at 4559 m and the equivalent V˙O2 at sea level for each participant also revealed no significant difference [83.9 (67.5–120.9) ml litre¹vs 81.2 (73.0–120.7) ml litre⁻¹, respectively, P=0.225].

Conclusion

In acclimatized individuals at 4559 m, there was a decline in maximum absolute C(a−v)O₂ during exercise but no alteration in OER calculated using central venous oxygen measurements. This suggests that oxygen extraction may have become limited after exposure to 7–8 days of hypoxaemia.

Metabolic monitoring in the intensive care unit: a comparison of the Medgraphics Ultima, Deltatrac II, and Douglas bag collection methods

BACKGROUND

The accuracy of oxygen consumption measurement by indirect calorimeters is poorly validated in mechanically ventilated intensive care patients where multiple confounders exist. This study sought to compare the Medgraphics Ultima (MGU) and Deltatrac II (DTII) devices, and the Douglas bag (DB) technique in mechanically ventilated patients at rest.

METHODS

Prospective comparison of oxygen consumption measurement using three indirect calorimetry techniques in stable, resting mechanically ventilated patients at rest. Oxygen consumption (VO2), carbon dioxide production (VCO2), resting energy expenditure (REE), and respiratory quotient (RQ) were recorded breath-by-breath by the MGU over a 30-75 min period. During this time, simultaneous measurements were taken using the DTII, the DB, or both.

RESULTS

While there was no systematic error (bias) between measurements made by the three techniques (VO2: MGU vs DTII 3.6%, MGU vs DB 3.3%), the limits of agreement were wide (VO2: MGU vs DTII 33%, MGU vs DB 54%).

CONCLUSIONS

Resting oxygen consumption values in stable mechanically ventilated patients measured by the three techniques showed acceptable bias but poor precision. There is an important clinical and research need to develop new indirect calorimeters specifically tailored to measure oxygen consumption during mechanical ventilation.

Effect of prehabilitation on objectively measured physical fitness after neoadjuvant treatment in preoperative rectal cancer patients: a blinded interventional pilot study

BACKGROUND

Patients requiring surgery for locally advanced rectal cancer often additionally undergo neoadjuvant chemoradiotherapy (NACRT), of which the effects on physical fitness are unknown. The aim of this feasibility and pilot study was to investigate the effects of NACRT and a 6 week structured responsive exercise training programme (SRETP) on oxygen uptake [Formula: see text] at lactate threshold ([Formula: see text]) in such patients.

METHODS

We prospectively studied 39 consecutive subjects (27 males) with T3-4/N+ resection margin threatened rectal cancer who completed standardized NACRT. Subjects underwent cardiopulmonary exercise testing at baseline (pre-NACRT), at week 0 (post-NACRT), and week 6 (post-SRETP). Twenty-two subjects undertook a 6 week SRETP on a training bike (three sessions per week) between week 0 and week 6 (exercise group). These were compared with 17 contemporaneous non-randomized subjects (control group). Changes in [Formula: see text] at [Formula: see text] over time and between the groups were compared using a compound symmetry covariance linear mixed model.

RESULTS

Of 39 recruited subjects, 22 out of 22 (exercise) and 13 out of 17 (control) completed the study. There were differences between the exercise and control groups at baseline [age, ASA score physical status, World Health Organisation performance status, and Colorectal Physiologic and Operative Severity Score for the Enumeration of Mortality and Morbidity (CR-POSSUM) predicted mortality]. In all subjects, [Formula: see text] at [Formula: see text] significantly reduced between baseline and week 0 [-1.9 ml kg(-1) min(-1); 95% confidence interval (CI) -1.3, -2.6; P<0.0001]. In the exercise group, [Formula: see text] at [Formula: see text] significantly improved between week 0 and week 6 (+2.1 ml kg(-1) min(-1); 95% CI +1.3, +2.9; P<0.0001), whereas the control group values were unchanged (-0.7 ml kg(-1) min(-1); 95% CI -1.66, +0.37; P=0.204).

CONCLUSIONS

NACRT before rectal cancer surgery reduces physical fitness. A structured exercise intervention is feasible post-NACRT and returns fitness to baseline levels within 6 weeks.

CLINICAL TRIAL REGISTRATION NCT

01325909.

The effect of neoadjuvant chemotherapy on physical fitness and survival in patients undergoing oesophagogastric cancer surgery

BACKGROUND

Neoadjuvant chemotherapy (NAC) followed by surgery for resectable oesophageal or gastric cancer improves outcome when compared with surgery alone. However NAC has adverse effects. We assess here whether NAC adversely affects physical fitness and whether such an effect is associated with impaired survival following surgery.

METHODS

We prospectively studied 116 patients with oesophageal or gastric cancer to assess the effect of NAC on physical fitness, of whom 89 underwent cardiopulmonary exercise testing (CPET) before NAC and proceeded to surgery. 39 patients were tested after all cycles of NAC but prior to surgery. Physical fitness was assessed by measuring oxygen uptake (VO₂ in ml kg(-1) min(-1)) at the estimated lactate threshold (θL) and at peak exercise (VO₂ peak in ml kg(-1) min(-1)).

RESULTS

VO₂ at θL and at peak were significantly lower after NAC compared to pre-NAC values: VO₂ at θL 14.5 ± 3.8 (baseline) vs. 12.3 ± 3.0 (post-NAC) ml kg(-1) min(-1); p ≤ 0.001; VO₂ peak 20.8 ± 6.0 vs. 18.3 ± 5.1 ml kg(-1) min(-1); p ≤ 0.001; absolute VO₂ (ml min(-1)) at θL and peak were also lower post-NAC; p ≤ 0.001. Decreased baseline VO₂ at θL and peak were associated with increased one year mortality in patients who completed a full course of NAC and had surgery; p = 0.014.

CONCLUSION

NAC before cancer surgery significantly reduced physical fitness in the overall cohort. Lower baseline fitness was associated with reduced one-year-survival in patients completing NAC and surgery, but not in patients who did not complete NAC. It is possible that in some patients the harms of NAC may outweigh the benefits. Trials Registry Number: NCT01335555.

Effect of prehabilitation on objectively measured physical fitness after neoadjuvant treatment in preoperative rectal cancer patients: a blinded interventional pilot study

BACKGROUND

Patients requiring surgery for locally advanced rectal cancer often additionally undergo neoadjuvant chemoradiotherapy (NACRT), of which the effects on physical fitness are unknown. The aim of this feasibility and pilot study was to investigate the effects of NACRT and a 6 week structured responsive exercise training programme (SRETP) on oxygen uptake [Formula: see text] at lactate threshold ([Formula: see text]) in such patients.

METHODS

We prospectively studied 39 consecutive subjects (27 males) with T3-4/N+ resection margin threatened rectal cancer who completed standardized NACRT. Subjects underwent cardiopulmonary exercise testing at baseline (pre-NACRT), at week 0 (post-NACRT), and week 6 (post-SRETP). Twenty-two subjects undertook a 6 week SRETP on a training bike (three sessions per week) between week 0 and week 6 (exercise group). These were compared with 17 contemporaneous non-randomized subjects (control group). Changes in [Formula: see text] at [Formula: see text] over time and between the groups were compared using a compound symmetry covariance linear mixed model.

RESULTS

Of 39 recruited subjects, 22 out of 22 (exercise) and 13 out of 17 (control) completed the study. There were differences between the exercise and control groups at baseline [age, ASA score physical status, World Health Organisation performance status, and Colorectal Physiologic and Operative Severity Score for the Enumeration of Mortality and Morbidity (CR-POSSUM) predicted mortality]. In all subjects, [Formula: see text] at [Formula: see text] significantly reduced between baseline and week 0 [-1.9 ml kg(-1) min(-1); 95% confidence interval (CI) -1.3, -2.6; P<0.0001]. In the exercise group, [Formula: see text] at [Formula: see text] significantly improved between week 0 and week 6 (+2.1 ml kg(-1) min(-1); 95% CI +1.3, +2.9; P<0.0001), whereas the control group values were unchanged (-0.7 ml kg(-1) min(-1); 95% CI -1.66, +0.37; P=0.204).

CONCLUSIONS

NACRT before rectal cancer surgery reduces physical fitness. A structured exercise intervention is feasible post-NACRT and returns fitness to baseline levels within 6 weeks.

CLINICAL TRIAL REGISTRATION NCT

01325909.

Survival after postoperative morbidity: a longitudinal observational cohort study

Background

Previous studies have suggested that there may be long-term harm associated with postoperative complications. Uncertainty exists however, because of the need for risk adjustment and inconsistent definitions of postoperative morbidity.

Methods

We did a longitudinal observational cohort study of patients undergoing major surgery. Case-mix adjustment was applied and morbidity was recorded using a validated outcome measure. Cox proportional hazards modelling using time-dependent covariates was used to measure the independent relationship between prolonged postoperative morbidity and longer term survival.

Results

Data were analysed for 1362 patients. The median length of stay was 9 days and the median follow-up time was 6.5 yr. Independent of perioperative risk, postoperative neurological morbidity (prevalence 2.9%) was associated with a relative hazard for long-term mortality of 2.00 [P=0.001; 95% confidence interval (CI) 1.32–3.04]. Prolonged postoperative morbidity (prevalence 15.6%) conferred a relative hazard for death in the first 12 months after surgery of 3.51 (P<0.001; 95% CI 2.28–5.42) and for the next 2 yr of 2.44 (P<0.001; 95% CI 1.62–3.65), returning to baseline thereafter.

Conclusions

Prolonged morbidity after surgery is associated with a risk of premature death for a longer duration than perhaps is commonly thought; however, this risk falls with time. We suggest that prolonged postoperative morbidity measured in this way may be a valid indicator of the quality of surgical healthcare. Our findings reinforce the importance of research and quality improvement initiatives aimed at reducing the duration and severity of postoperative complications.

Cardiopulmonary exercise testing for the prediction of morbidity risk after rectal cancer surgery

BACKGROUND

This study investigated the relationship between objectively measured physical fitness variables derived by cardiopulmonary exercise testing (CPET) and in-hospital morbidity after rectal cancer surgery.

METHODS

Patients scheduled for rectal cancer surgery underwent preoperative CPET (reported blind to patient characteristics) with recording of morbidity (recorded blind to CPET variables). Non-parametric receiver operating characteristic (ROC) curves and logistic regression were used to assess the relationship between CPET variables and postoperative morbidity.

RESULTS

Of 105 patients assessed, 95 (72 men) were included; ten patients had no surgery and were excluded (3 by choice, 7 owing to unresectable metastasis). Sixty-eight patients had received neoadjuvant treatment. ROC curve analysis of oxygen uptake (V˙o2 ) at estimated lactate threshold (θ^L ) and peak V˙o2 gave an area under the ROC curve of 0·87 (95 per cent confidence interval 0·78 to 0·95; P < 0·001) and 0·85 (0·77 to 0·93; P < 0·001) respectively, indicating that they can help discriminate patients at risk of postoperative morbidity. The optimal cut-off points identified were 10·6 and 18·6 ml per kg per min for V˙o2 at θ^L and peak respectively.

CONCLUSION

CPET can help predict morbidity after rectal cancer surgery.

The use of skeletal muscle near infrared spectroscopy and a vascular occlusion test at high altitude

Microcirculatory function, central to tissue regulation of oxygen flux, may be altered by the chronic hypoxemia experienced at high altitude. We hypothesized that at high altitude, adaptations within skeletal muscle would result in reduced oxygen consumption and reduced microcirculatory responsiveness, detectable by near infrared spectroscopy (NIRS) during a vascular occlusion test (VOT). The VOT comprised 3 min of noninvasive arterial occlusion; thenar eminence tissue oxygenation (Sto2) was measured by NIRS during the VOT at sea level, 4900 m and 5600 m (after 7 and 17 days at altitude, respectively) in 12 healthy volunteers. Data were derived from Sto2 time-curves using specifically designed computer software. Mean (±SD) resting Sto2 was reduced at 4900 m and 5600 m (69.3 (± 8.2)% (p=0.001) and 64.2 (± 6.1)% (p<0.001) respectively) when compared to sea level (84.4 (± 6.0)%. The rate of Sto2 recovery after vascular occlusion (Sto2 upslope) was significantly reduced at 4900 m (2.4 (± 0.4)%/sec) and 5600 m (2.4 (± 0.8)%/sec) compared to sea level (3.7 (± 1.3)%/sec) (p=0.021 and p=0.032, respectively). There was no change from sea level in the rate of desaturation during occlusion (Sto2 downslope) at either altitude. The findings suggest that in resting skeletal muscle of acclimatizing healthy volunteers at high altitude, microvascular reactivity is reduced (Sto2 upslope after a short period of ischemia) but that oxygen consumption remains unchanged (Sto2 downslope).

The effects of neoadjuvant chemoradiotherapy on physical fitness and morbidity in rectal cancer surgery patients

BACKGROUND

Neoadjuvant chemoradiotherapy (NACRT) followed by surgery for resectable locally advanced rectal cancer improves outcome compared with surgery alone. Our primary hypothesis was that NACRT impairs objectively-measured physical fitness. We also wished to explore the relationship between fitness and postoperative outcome.

METHOD

In an observational study, we prospectively studied 27 consecutive patients, of whom 25 undertook cardiopulmonary exercise testing (CPET) 2 weeks before and 7 weeks after standardized NACRT, then underwent surgery. In-hospital post-operative morbidity and mortality were recorded. Patients were followed up to 1 year for mortality. Data was analysed blind to clinical details. Receiver-operating characteristic (ROC) analysis defined the predictive value of CPET for in-hospital morbidity at day 5.

RESULTS

Oxygen uptake ( [Formula: see text] in ml kg(-1) min(-1)) at estimated lactate threshold (θˆL) and at peak exercise ( [Formula: see text] at peak in ml kg(-1) min(-1)) both significantly decreased post-NACRT: [Formula: see text] at θˆL 12.1 (pre-NACRT) vs. 10.6 (post-NACRT), p < 0.001 (95%CI -1.7, -1.2); [Formula: see text] at peak 18.1 vs. 16.7, p < 0.001 (95%CI -3.1, -1.0). Optimal [Formula: see text] at θˆL and peak pre-NACRT for predicting postoperative morbidity were 12.0 and 18.1 ( [Formula: see text] at θˆL - AUC = 0.71, 77% sensitive and 75% specific; [Formula: see text] at peak - AUC = 0.75, 78% sensitive and 76% specific). Optimal [Formula: see text] at θˆL and peak post-NACRT for predicting postoperative morbidity were 10.7 and 16.7 ( [Formula: see text] at θˆL - AUC = 0.72, 77% sensitive and 83% specific; [Formula: see text] at peak - AUC = 0.80, 85% sensitive and 83% specific).

CONCLUSION

NACRT before major rectal cancer surgery significantly decreased physical fitness as assessed by CPET.

TRIALS REGISTRY NUMBER

NCT01334593.

The effect of neoadjuvant chemotherapy on physical fitness and survival in patients undergoing oesophagogastric cancer surgery

BACKGROUND

Neoadjuvant chemotherapy (NAC) followed by surgery for resectable oesophageal or gastric cancer improves outcome when compared with surgery alone. However NAC has adverse effects. We assess here whether NAC adversely affects physical fitness and whether such an effect is associated with impaired survival following surgery.

METHODS

We prospectively studied 116 patients with oesophageal or gastric cancer to assess the effect of NAC on physical fitness, of whom 89 underwent cardiopulmonary exercise testing (CPET) before NAC and proceeded to surgery. 39 patients were tested after all cycles of NAC but prior to surgery. Physical fitness was assessed by measuring oxygen uptake (VO₂ in ml kg(-1) min(-1)) at the estimated lactate threshold (θL) and at peak exercise (VO₂ peak in ml kg(-1) min(-1)).

RESULTS

VO₂ at θL and at peak were significantly lower after NAC compared to pre-NAC values: VO₂ at θL 14.5 ± 3.8 (baseline) vs. 12.3 ± 3.0 (post-NAC) ml kg(-1) min(-1); p ≤ 0.001; VO₂ peak 20.8 ± 6.0 vs. 18.3 ± 5.1 ml kg(-1) min(-1); p ≤ 0.001; absolute VO₂ (ml min(-1)) at θL and peak were also lower post-NAC; p ≤ 0.001. Decreased baseline VO₂ at θL and peak were associated with increased one year mortality in patients who completed a full course of NAC and had surgery; p = 0.014.

CONCLUSION

NAC before cancer surgery significantly reduced physical fitness in the overall cohort. Lower baseline fitness was associated with reduced one-year-survival in patients completing NAC and surgery, but not in patients who did not complete NAC. It is possible that in some patients the harms of NAC may outweigh the benefits. Trials Registry Number: NCT01335555.

Cardiopulmonary exercise variables are associated with postoperative morbidity after major colonic surgery: a prospective blinded observational study

BACKGROUND

Postoperative complications are associated with reduced fitness. Cardiopulmonary exercise testing (CPET) has been used in risk stratification. We investigated the relationship between preoperative CPET and in-hospital morbidity in major colonic surgery.

METHODS

We prospectively studied 198 patients undergoing major colonic surgery (excluding neoadjuvant cancer therapy), performing preoperative CPET (reported blind to clinical state), and recording morbidity (assessed blind to CPET), postoperative outcome, and length of stay.

RESULTS

Of 198 patients, 62 were excluded: 11 had emergency surgery, 25 had no surgery, 23 had incomplete data, and three were unable to perform CPET. One hundred and thirty-six (89 males, 47 females) were available for analysis. The median age was 71 [inter-quartile range (IQR) 62-77] yr. Sixty-five patients (48%) had a complication at day 5 after operation. Measurements significantly lower in patients with complications than those without were O2 uptake (VO₂) at estimated lactate threshold (θ(L)) [median 9.9 (IQR 8.3-12.7) vs 11.2 (9.5-14.2) ml kg(-1) min(-1), P<0.01], VO₂ at peak [15.2 (12.6-18.1) vs 17.2 (13.7-22.5) ml kg(-1) min(-1), P=0.01], and ventilatory equivalent for CO2 (V(E)/VCO₂) at θ(L) [31.3 (28.0-34.8) vs 33.9 (30.0-39.1), P<0.01]. A final multivariable logistic regression model contained VO₂ at θ(L) {one-point change odds ratio (OR) 0.77 [95% confidence interval (CI) 0.66-0.89], P<0.0005; two-point change OR 0.61 (0.46-0.81) and gender [OR 4.42 (1.78-9.88), P=0.001]}, and was reasonably able to discriminate those with and without complications (AUC 0.71, CI 0.62-0.80, 68% sensitivity, 65% specificity).

CONCLUSIONS

CPET variables are associated with postoperative morbidity. A multivariable model with VO₂ at θ(L) and gender discriminates those with complications after colonic surgery.

Perioperative increase in global blood flow to explicit defined goals and outcomes after surgery: a Cochrane Systematic Review

This systematic review and meta-analysis summarizes the clinical effects of increasing perioperative blood flow using fluids with or without inotropes/vasoactive drugs to explicit defined goals in adults. We included randomized controlled trials of adult patients (aged 16 years or older) undergoing surgery. We included 31 studies of 5292 participants. There was no difference in mortality at the longest follow-up: 282/2615 (10.8%) died in the control group and 238/2677 (8.9%) in the treatment group, RR of 0.89 (95% CI: 0.76-1.05; P=0.18). However, the results were sensitive to analytical methods and withdrawal of studies with methodological limitations. The intervention reduced the rate of three morbidities (renal failure, respiratory failure, and wound infections) but not the rates of arrhythmia, myocardial infarction, congestive cardiac failure, venous thrombosis, and other types of infections. The number of patients with complications was also reduced by the intervention. Hospital length of stay was reduced in the treatment group by 1.16 days. There was no difference in critical care length of stay. The primary analysis of this review showed no difference between groups but this result was sensitive to the method of analysis, withdrawal of studies with methodological limitations, and was dominated by a single large study. Patients receiving this intervention stayed in hospital 1 day less with fewer complications. It is unlikely that the intervention causes harm. The balance of current evidence does not support widespread implementation of this approach to reduce mortality but does suggest that complications and duration of hospital stay are reduced.

Preoperative aerobic exercise training in elective intra-cavity surgery: a systematic review

Reduced physical fitness is associated with increased risk of complications after intra-cavity surgery. Aerobic exercise training interventions improve physical fitness in clinical populations. However, it is unclear whether implementing a preoperative aerobic exercise training intervention improves outcome after intra-cavity surgery. We conducted a systematic review (Embase and PubMed, to April 2011) to address the question: does preoperative aerobic exercise training in intra-cavity surgery result in improved postoperative clinical outcomes? Secondary objectives were to describe the effect of such an intervention on physical fitness and health-related quality of life (HRQL) and report feasibility, safety, and cost-effectiveness. Ten studies were identified from 2443 candidate abstracts. Eight studies were small (<100 patients) and all were single centre. Seven studies reported clinical outcomes. Two studies were controlled trials and two used a sham intervention group. One study in cardiac surgery demonstrated reduced postoperative hospital and intensive care length of stay in the intervention group. Eight studies showed improvement in ≥ 1 measure of physical fitness after the intervention. HRQL was reported in five studies; three showed improved HRQL after the intervention. The frequency, duration, and intensities of the exercise interventions varied across the studies. Adherence to exercise interventions was good. Two exercise-related adverse events (transient hypotension) were reported. Evidence for improved postoperative clinical outcome after preoperative aerobic exercise training interventions is limited. However, preoperative aerobic exercise training seems to be generally effective in improving physical fitness in patients awaiting intra-cavity surgery and appears to be feasible and safe.

Preoperative exercise capacity in adult inflammatory bowel disease sufferers, determined by cardiopulmonary exercise testing

BACKGROUND AND AIMS

Aerobic exercise capacity appears impaired in children with inflammatory bowel disease (IBD). Whether this holds true in adults with IBD is not known. Using cardiopulmonary exercise testing (CPET), we assessed anaerobic threshold (AT) in such patients comparing data with reference values and other elective surgical patients. We also sought to confirm whether the presence of a fistula further reduced AT.

METHODS

CPET was performed between November 2007 and December 2010 on patients awaiting abdominopelvic surgery. Gender-specific normal reference values were used for comparison. Unadjusted comparison between two groups was made using Mann-Whitney U test and by unpaired t test. Data were adjusted by analysis of covariance, using age and sex as covariates. Differences between patients' observed values and reference values were tested using paired t tests.

RESULTS

Four hundred and fourteen patients (234 male) were studied (mean ± SD age, 56.6 ± 16.4 years; weight, 74.2 ± 15.6 kg). Adjusted AT values in Crohn's disease (CD) were lower than colorectal cancer (11.4 ± 3.4 vs 13.2 ± 3.5 ml.kg(-1).min(-1), p = 0.03) and for all other colorectal disease groups combined (12.6 ± 3.5 ml.kg(-1).min(-1), p = 0.03). AT of Ulcerative colitis (UC) and CD patients together were reduced compared to population reference values (p < 0.05).

CONCLUSION

After adjusting for age and sex, CD patients had a reduced AT compared to patients with colorectal cancer and other colorectal disease groups combined. The pathogenesis of this low AT remains to be defined and warrants further investigation.

Cardiopulmonary exercise testing predicts postoperative outcome in patients undergoing gastric bypass surgery

BACKGROUND

For several types of non-cardiac surgery, the cardiopulmonary exercise testing (CPET)-derived variables anaerobic threshold (AT), peak oxygen consumption (VO2 peak), and ventilatory equivalent for CO(2) (VE/VCO2 ) are predictive of increased postoperative risk: less physically fit patients having a greater risk of adverse outcome. We investigated this relationship in patients undergoing gastric bypass surgery.

METHODS

All patients (<190 kg) who were referred for CPET and underwent elective gastric bypass surgery at the Whittington Hospital NHS Trust between September 1, 2009, and February 25, 2011, were included in the study (n=121). Fifteen patients did not complete CPET. CPET variables (VO2 peak, AT, and VE/VCO2 ) were derived for 106 patients. The primary outcome variables were day 5 morbidity and hospital length of stay (LOS). The independent t-test and Fisher's exact test were used to test for differences between surgical outcome groups. The predictive capacity of CPET markers was determined using receiver operating characteristic (ROC) curves.

RESULTS

The AT was lower in patients with postoperative complications than in those without [9.9 (1.5) vs 11.1 (1.7) ml kg(-1) min(-1), P=0.049] and in patients with a LOS>3 days compared with LOS ≤ 3 days [10.4 (1.4) vs 11.3 (1.8) ml kg(-1) min(-1), P=0.023]. ROC curve analysis identified AT as a significant predictor of LOS>3 days (AUC 0.640, P=0.030). The VO2 peak and VE/VCO2 were not associated with postoperative outcome.

CONCLUSIONS

AT, determined using CPET, predicts LOS after gastric bypass surgery.

Reduced coagulation at high altitude identified by thromboelastography

The impact of hypoxaemia on blood coagulation remains unclear despite use of a variety of measures to address the issue. We report the first use of thromboelastography (TEG) at high altitude to describe the dynamics of clot formation in whole blood samples. Seventeen healthy volunteers ascended to 5,300 m following an identical ascent profile; TEG measurements at 4,250 m and 5,300 m were compared with those from sea level. Peripheral oxygen saturation (SpO2) and haematocrit were also measured. Ascent resulted in a decline in SpO2 from 97.8 (± 1.2) % at sea level to 86.9 (± 3.3) % at 4,250 m and 79.5 (± 5.8) % at 5,300 m (p<0.001); haematocrit rose from 43.7 (± 2.8) % at sea level, to 46.7 (± 3.9) % and 52.6 (± 3.2) % at 4,250 m and 5,300 m, respectively (p<0.01). TEG reaction (R)-time and kinetic (K)-time were both increased at 5,300 m compared to sea level, 8.95 (± 1.37) minutes (min) to 11.69 (± 2.91) min (p=0.016) and 2.40 (± 0.66) min to 4.99 (± 1.67) min (p<0.001), respectively. Additionally the alpha (α)-angle was decreased from 57.7 (± 8.2) to 51.6 (± 6.4) (p<0.001). There was no change in maximum amplitude (MA) on ascent to altitude. These changes are consistent with an overall pattern of slowed coagulation at high altitude.