Physiological performance and inflammatory markers as indicators of complications after oesophageal cancer surgery.

BACKGROUND: The extent to which physiological factors influence outcome following oesophageal cancer surgery is poorly understood. This study aimed to evaluate the extent to which cardiorespiratory fitness and selected metabolic factors predicted complications after surgery for carcinoma. METHODS: Two hundred and twenty-five consecutive patients underwent preoperative cardiopulmonary exercise testing to determine peak oxygen uptake ( V ˙ o2peak ), anaerobic threshold and the ventilatory equivalent for carbon dioxide ( V ˙ e/ V ˙ co2 ). Cephalic venous blood was assayed for serum C-reactive protein (CRP) and albumin levels, and a full blood count was done. The primary outcome measure was the Morbidity Severity Score (MSS). RESULTS: One hundred and ninety-eight patients had anatomical resection. A high MSS (Clavien-Dindo grade III or above) was found in 48 patients (24·2 per cent) and was related to an increased CRP concentration (area under the receiver operating characteristic (ROC) curve (AUC) 0·62, P = 0·001) and lower V ˙ o2peak (AUC 0·36, P = 0·003). Dichotomization of CRP levels (above 10 mg/l) and V ˙ o2peak (below 18·6 ml per kg per min) yielded adjusted odds ratios (ORs) for a high MSS of 2·86 (P = 0·025) and 2·92 (P = 0·002) respectively. Compared with a cohort with a low Combined Inflammatory and Physiology Score (CIPS), the OR was 1·70 (95 per cent c.i. 0·85 to 3·39) for intermediate and 27·47 (3·12 to 241·69) for high CIPS (P < 0·001). CONCLUSION: CRP and V ˙ o2peak were independently associated with major complications after potentially curative oesophagectomy for cancer. A composite risk score identified a group of patients with a high risk of developing complications.

ANTECEDENTES: El grado en el que los factores fisiológicos influyen en el resultado tras la cirugía del cáncer de esófago no se conoce bien. Este estudio tuvo como objetivo evaluar en qué medida el estado cardiorrespiratorio y los factores metabólicos seleccionados predecían complicaciones después de cirugía por cáncer. MÉTODOS: Pacientes consecutivos fueron sometidos a una prueba de ejercicio cardiopulmonar preoperatoria para determinar el consumo pico de oxígeno (peak oxygen uptake, V ̇ O2Peak ), el umbral anaeróbico (anaerobic threshold, AT) y el equivalente ventilatorio de dióxido de carbono (ventilatory equivalent for carbon dioxide, V ̇ E / V ̇ CO2 ). Se extrajo sangre de la vena cefálica para analizar la proteína C reactiva (C-reactive protein, CRP) sérica, albumina y hemograma completo. La medida de resultado primario fue la puntuación de la gravedad de la morbilidad (Morbidity Severity Score, MSS). RESULTADOS: Se observó MSS (Clavien-Dindo > 2) en 33 (17,7%) pacientes, relacionándose con CRP elevada (AUC 0,69, P = 0,001) y V ̇O2Peak baja (AUC 0,33, P = 0,003). La dicotomización de la CRP (por encima de 10 mg/L) y V ̇O2Peak (por debajo de 18,6 mL/kg/min) se asociada a una razón de oportunidades (odds ratio, OR) de 4,01 (P = 0,002) y 3,74 (P = 0,002) para MSS y CD > 2, respectivamente. En comparación con la cohorte con una puntuación combinada inflamatoria y fisiológica (Combined Inflammatory and Physiology Score, CIPS) baja, el OR fue de 1,70 (i.c. del 95% 0,85-3,39) para una CIPS intermedia y de 27,47 (3,12-241,69, P < 0,001) para CIPS elevada. CONCLUSIÓN: CRP y V ̇O2Peak se asociaron de forma independiente con complicaciones mayores tras esofaguectomía potencialmente curativa por cáncer. Una puntuación combinada de riesgo identificó a un grupo de pacientes con un riesgo elevado de desarrollar complicaciones.

Cardiorespiratory fitness fails to predict short-term postoperative mortality in patients undergoing elective open surgery for abdominal aortic aneurysm.

INTRODUCTION: Preoperative cardiopulmonary exercise testing aids surgical risk stratification and is an established predictor of mid- to long-term survival in patients undergoing elective open abdominal aortic aneurysm repair. Whether cardiopulmonary exercise testing also predicts 30-day mortality in this population remains to be established. MATERIALS AND METHODS: Data for 109 patients (mean age 72 years) who underwent cardiopulmonary exercise testing to assess risk for surgical abdominal aortic aneurysm repair was analysed. Patients were classified according to cardiopulmonary fitness as fit (peak oxygen uptake ≥ 15ml O2.kg-1.min-1) or unfit (peak oxygen uptake less than 15ml O2.kg-1.min-1) and further stratified according to clamp position (infrarenal or suprarenal). Between-group postoperative outcomes were compared for in-hospital 30-day mortality, postoperative morbidity scale scores (day 5) and hospital length of stay. RESULTS: Seventy-nine patients underwent open surgery and 30 patients were treated conservatively. No deaths were recorded at 30 days post-surgery. Unfit patients with infrarenal clamping exhibited higher postoperative morbidity scale scores (64% vs 26%) and longer length of stay (four days) than fit patients (p < 0.05). Conversely, with suprarenal clamping, postoperative morbidity scale scores were similar and length of stay longer (three days) in fit compared with unfit patients (p < 0.05). DISCUSSION AND CONCLUSION: Preoperative fitness level defined by peak oxygen uptake failed to identify patients at risk of 30-day mortality when undergoing elective abdominal aortic aneurysm repair. Postoperative morbidity and length of stay in patients with suprarenal clamping was high independent of cardiopulmonary fitness. These findings suggest that cardiopulmonary exercise testing may be a useful predictor of complications following infrarenal rather than suprarenal clamping but may not be a good predictor of 30-day mortality.

Cardiorespiratory fitness is impaired and predicts mid-term postoperative survival in patients with abdominal aortic aneurysm disease.

NEW FINDINGS: What is the central question of this study? To what extent cardiorespiratory fitness is impaired in patients with abdominal aortic aneurysmal (AAA) disease and corresponding implications for postoperative survival requires further investigation. What is the main finding and its importance? Cardiorespiratory fitness is impaired in patients with AAA disease. Patients with peak oxygen uptake of <13.1 ml O2  kg-1  min-1 and ventilatory equivalent for carbon dioxide at anaerobic threshold ≥34 are associated with increased risk of postoperative mortality at 2 years. These findings demonstrate that cardiorespiratory fitness can predict mid-term postoperative survival in AAA patients, which may help to direct care provision. ABSTRACT: Preoperative cardiopulmonary exercise testing is a standard assessment of cardiorespiratory fitness (CRF) and risk stratification. However, to what extent CRF is impaired in patients undergoing surgical repair of abdominal aortic aneurysm (AAA) disease and the corresponding implications for postoperative outcome requires further investigation. We measured CRF during an incremental exercise test to exhaustion using online respiratory gas analysis in patients with AAA disease (n = 124, aged 72 ± 7 years) and healthy sedentary control subjects (n = 104, aged 70 ± 7 years). Postoperative survival was examined for association with CRF, and threshold values were calculated for independent predictors of mortality. Patients who underwent preoperative cardiopulmonary exercise testing before surgical repair had lower CRF [age-adjusted mean difference of 12.5 ml O2  kg-1  min-1 for peak oxygen uptake ( V ̇ O 2 peak ), P < 0.001 versus control subjects]. After multivariable analysis, both V ̇ O 2 peak and the ventilatory equivalent for carbon dioxide at anaerobic threshold ( V ̇ E / V ̇ C O 2 - AT ) were independent predictors of mid-term postoperative survival (2 years). Hazard ratios of 5.27 (95% confidence interval 1.62-17.14, P = 0.006) and 3.26 (95% confidence interval 1.00-10.59, P = 0.049) were observed for V ̇ O 2 peak  < 13.1 ml O2  kg-1  min-1 and V ̇ E / V ̇ C O 2 - AT ≥ 34, respectively. Thus, CRF is lower in patients with AAA, and those with a V ̇ O 2 peak  < 13.1 ml O2  kg-1  min-1 and V ̇ E / V ̇ C O 2 - AT ≥ 34 are associated with a markedly increased risk of postoperative mortality. Collectively, our findings demonstrate that CRF can predict mid-term postoperative survival in AAA patients, which may help to direct care provision.

The cardiopulmonary exercise test grey zone; optimising fitness stratification by application of critical difference.

BACKGROUND: Cardiorespiratory fitness can inform patient care, although to what extent natural variation in CRF influences clinical practice remains to be established. We calculated natural variation for cardiopulmonary exercise test (CPET) metrics, which may have implications for fitness stratification. METHODS: In a two-armed experiment, critical difference comprising analytical imprecision and biological variation was calculated for cardiorespiratory fitness and thus defined the magnitude of change required to claim a clinically meaningful change. This metric was retrospectively applied to 213 patients scheduled for colorectal surgery. These patients underwent CPET and the potential for misclassification of fitness was calculated. We created a model with boundaries inclusive of natural variation [critical difference applied to oxygen uptake at anaerobic threshold (V˙O2-AT): 11 ml O2 kg-1 min-1, peak oxygen uptake (V˙O2 peak): 16 ml O2 kg-1 min-1, and ventilatory equivalent for carbon dioxide at AT (V̇E/V̇CO2-AT): 36]. RESULTS: The critical difference for V˙O2-AT, V˙O2 peak, and V˙E/V˙CO2-AT was 19%, 13%, and 10%, respectively, resulting in false negative and false positive rates of up to 28% and 32% for unfit patients. Our model identified boundaries for unfit and fit patients: AT <9.2 and ≥13.6 ml O2 kg-1 min-1, V˙O2 peak <14.2 and ≥18.3 ml kg-1 min-1, V˙E/V˙CO2-AT ≥40.1 and <32.7, between which an area of indeterminate-fitness was established. With natural variation considered, up to 60% of patients presented with indeterminate-fitness. CONCLUSIONS: These findings support a reappraisal of current clinical interpretation of cardiorespiratory fitness highlighting the potential for incorrect fitness stratification when natural variation is not accounted for.

Prognostic significance of age in the radical treatment of oesophageal cancer with surgery or chemoradiotherapy: a prospective observational cohort study.

AIMS: To compare the outcomes of stage-directed surgical therapy and chemoradiotherapy (CRT) for oesophageal cancer and to determine if a significant age-treatment interaction exists to guide therapy. MATERIALS AND METHODS: Five hundred and eight consecutive patients with oesophageal cancer suitable for radical treatment based on radiological stage and performance status were studied (275 surgery; 93 surgery alone, 131 neoadjuvant chemotherapy, 51 neoadjuvant CRT and 233 definitive CRT). The primary measure of outcome was survival. RESULTS: Thirty-day mortality rates and 2-year survival after surgery and CRT in patients<70 years were 2.4 and 57.5%, respectively, compared with 0 (P=0.207) and 47.3% (P=0.011), respectively. Thirty-day mortality rates and 2-year survival after surgery and CRT in patients>or=70 years were 7.0 and 45.1%, respectively, compared with 0 (P=0.029) and 46.3% (P=0.992), respectively. Multivariate analysis including only surgical patients in the model revealed three factors to be independently and significantly associated with survival; endoscopic ultrasound (EUS) T stage (P=0.033), EUS lymph node metastasis count (>or=2 versus 0: hazard ratio 1.67, 95% confidence interval 1.06-2.92, P=0.026), and age>or=70 years (hazard ratio 1.51, 95% confidence interval 1.05-2.16, P=0.025). CONCLUSION: Overall survival for patients treated with surgery was strongly age dependent around the age of 70 years, and patients>or=70 years with oesophageal cancer should be aware that outcomes after CRT are similar to those after surgery.

Anions and the anaesthetist.

Anions are the negative components of most chemical structures and play many important physiological and pharmacological roles that are of interest to the anaesthetist. Their relevance is reviewed with a particular emphasis on the inorganic anions (halides, bicarbonate, phosphate and sulphate) and the significance and limitations of the anion gap. Organic anions (albumin, lactate) are also discussed, albeit briefly. The suitability of anions for their role in neurotransmission and acid-base balance is outlined.

Laparoscopic cholecystectomy in the grossly obese: 4 years experience and review of literature.

BACKGROUND: Conventional abdominal surgery in grossly obese patients is associated with an increased rate of postoperative complications; thus, laparoscopic surgery may be preferred in these patients. PATIENTS AND METHODS: A prospective analysis was performed of 20 grossly obese patients who underwent laparoscopic cholecystectomy between April 1996 and April 2000 for symptomatic non-complicated gallstone disease. RESULTS: Technical problems at operation included difficulty with induction of pneumoperitoneum and introduction of the most lateral subcostal port, retraction of the gallbladder fundus, the need for longer instruments and the closure of the fascia. Laparoscopic cholecystectomy was successfully completed in 19 patients, but one patient required conversion to open operation. There were no anaesthetic difficulties. Two patients developed minor chest infections. The mean hospital stay was 2.9 days. CONCLUSION: Laparoscopic cholecystectomy is feasible and can be recommended for symptomatic gallstone disease in grossly obese patients.

Laparoscopic cholecystectomy in the presence of a lumboperitoneal shunt.

Laparoscopic cholecystectomy was performed safely in a 70-year-old man with a lumboperitoneal shunt. Techniques for preventing retrograde flow of carbon dioxide are described.

Prophylactic amrinone for weaning from cardiopulmonary bypass.

This prospective, randomised, double-blind, controlled clinical study was performed at a single tertiary referral centre to test the hypothesis that the prophylactic administration of amrinone before separation of a patient from cardiopulmonary bypass decreases the incidence of failure to wean, and to identify those patients who could be predicted to benefit from such pre-emptive management. Two hundred and thirty-four patients, scheduled to undergo elective cardiac surgery, were randomly allocated to receive either a bolus dose of 1.5 mg x kg(-1) amrinone over 15 min, followed by an infusion of 10 microg x kg(-1) x min(-1), or a bolus of placebo of equal volume followed by an infusion of placebo. Treatment with amrinone or placebo was initiated upon release of the aortic cross-clamp, before weaning from cardiopulmonary bypass. Anaesthetic technique, monitoring and myocardial preservation methods were standardised for both groups. Significantly fewer patients failed to wean in the group that received prophylactic amrinone than in the control group (7 vs. 21%, p = 0.002). Amrinone improved weaning success regardless of left ventricular ejection fraction, although this benefit was statistically significant only in the group with left ventricular ejection fractions > 55%. Of the 32 patients who failed to wean from cardiopulmonary bypass, 14 had normal pre-operative left ventricular ejection fractions.

Effect of weaning on oxygen consumption and cardiovascular function. A comparison of continuous flow and demand valve systems.

This study compared the continuous positive airways pressure mode of the demand valve system of the Engstrom Erica ventilator with a custom-made continuous flow continuous positive airways pressure system in terms of the oxygen cost of breathing during weaning from mechanical ventilation. Ten consecutive patients in our intensive care unit, with thermodilution pulmonary artery flotation catheters in situ, were studied. Measurements were carried out under steady-state conditions, initially when breathing spontaneously with continuous positive airways pressure via the Erica and then when transition to the continuous flow system was achieved. There were no significant differences between the two methods of providing continuous positive airways pressure in terms of the measured and derived physiological variables studied, with the exception of oxygen consumption. Oxygen consumption with the continuous flow system was significantly less than with the Erica (142.8 (SEM 31.4) ml.min-1.m-2 compared with 165.8 (SEM 30.5) ml.min-1.m-2, p < 0.05). This difference reflects the reduced oxygen cost of breathing when the custom-made continuous flow system was used during weaning.