Patients' inability to perform a preoperative cardiopulmonary exercise test or demonstrate an anaerobic threshold is associated with inferior outcomes after major colorectal surgery.

BACKGROUND: Surgical patients with poor functional capacity, determined by oxygen consumption at anaerobic threshold (AT) during cardiopulmonary exercise testing (CPET), experience longer hospital stays and worse short- and medium-term survival. However, previous studies excluded patients who were unable to perform a CPET or who failed to demonstrate an AT. We hypothesized that such patients are at risk of inferior outcomes after elective surgery. METHODS: All patients undergoing major colorectal surgery attempted CPET to assist in the planning of care. Patients were stratified by their test results into Fit (AT ≥ 11.0 ml O2 kg(-1) min(-1)), Unfit (AT < 11.0 ml O2 kg(-1) min(-1)), or Unable to CPET groups (failed to pedal or demonstrate an AT). For each group, we determined hospital stay and mortality. RESULTS: Between March 2009 and April 2010, 269 consecutive patients were screened, and proceeded to bowel resection. Median hospital stay was 8 days (IQR 5.1-13.4) and there were 44 deaths (16%) at 2 yr; 26 (9.7%) patients were categorized as Unable to CPET, 69 (25.7%) Unfit and 174 (64.7%) Fit. There were statistically significant differences between the three groups in hospital stay [median (IQR) 14.0 (10.5-23.8) vs 9.9 (5.5-15) vs 7.1 (4.9-10.8) days, P < 0.01] and mortality at 2 yr [11/26 (42%) vs 14/69 (20%) vs 19/174 (11%), respectively (P < 0.01)] although the differences between Unable and Unfit were not statistically different. CONCLUSIONS: Patients' inability to perform CPET is associated with inferior outcomes after major colorectal surgery. Future studies evaluating CPET in risk assessment for major surgery should report outcomes for this subgroup

Metabolic and haemodynamic effects of increased circulating adrenaline in man. Effect of labetalol, an alpha and beta blocker.

To simulate increased sympathoadrenal activity adrenaline was infused in normotensive subjects to achieve plasma adrenaline concentrations similar to those seen after myocardial infarction or hypoglycaemia. Adrenaline was infused after pretreatment for five days with labetalol 200 mg twice daily or placebo given in a random order. The rise in systolic blood pressure and the fall in diastolic blood pressure observed after the infusion of adrenaline (0.06 micrograms/kg/min) were prevented by labetalol and no increase in blood pressure was seen. Adrenaline infusion after pretreatment with placebo caused a profound fall in the serum potassium concentration (4.12-3.20 mmol(mEq)/l). Pretreatment with labetalol completely blocked adrenaline induced hypokalaemia (3.92-3.95 mmol(mEq)/l). Adrenaline induced T wave flattening and QTc prolongation were also prevented by labetalol. Thus labetalol can prevent the electrocardiographic, haemodynamic, and hypokalaemic effects of increased circulating adrenaline in man. The combination of alpha and beta blockade appears to be required to block the haemodynamic effects of adrenaline, and labetalol may, therefore, be useful in controlling both the metabolic and circulatory responses during increased sympathoadrenal activity

The effects of enalapril and spironolactone on terbutaline-induced hypokalemia

To investigate whether enalapril (E) 10 mg and spironolactone (S) 100 mg attenuate the hypokalemic effect of inhaled terbutaline (T)

Randomized controlled trial of stroke volume optimization during elective major abdominal surgery in patients stratified by aerobic fitness

Abstract BACKGROUND: The benefits of stroke volume optimization during surgery are unclear, with recent data not replicating the positive effects of earlier studies. METHODS: This was a randomized controlled trial of standard fluid therapy with or without supplementary blinded intraoperative stroke volume optimization in 220 patients having major elective rectal resection or cystectomy with ileal conduit. All patients were treated using a contemporary enhanced recovery pathway. Interventional fluid challenges used Gelofusine (B Braun, Germany), guided by stoke volume variability measured by LiDCOrapid (LiDCO, UK). Participants were stratified by aerobic fitness (characterized by preoperative cardiopulmonary exercise test), surgical specialty, and intended surgical approach (open or laparoscopic). The primary outcome was the prevalence of moderate or severe complications on day 5 after surgery, defined using the postoperative morbidity survey (POMS) criteria. RESULTS: Patients received ∼13 ml kg(-1) h(-1) of i.v. fluids during surgery. The intervention group received an additional mean (sd) 956 (896) ml Gelofusine. There were no statistically significant differences between groups in any primary or secondary end point. A positive POMS on postoperative day 5 was noted in 54 of 111 control subjects (48.6%) and 55 of 109 participants in the intervention group [50.5%; adjusted odds ratio 0.90 (95% confidence interval 0.52-1.57), P=0.717]. Mean (sd) hospital length of stay was 9.6 (6.8) days in the control group and 11.8 (11.5) days in the intervention group (adjusted difference -2.1 (-4.6 to 0.3) days, P=0.091). There was no statistical interaction between stroke volume optimization and aerobic fitness in terms of rate of complications or length of stay. CONCLUSIONS: Algorithm-driven stroke volume optimization is of no benefit when superimposed on a liberal baseline fluid regimen in patients having elective major abdominal surgery, when stratified to minimize differences in fitness and surgical approach between groups. CLINICAL TRIAL REGISTRATION: ISRCTN21597243