Peripheral oxygen extraction in patients with malignant obstructive jaundice

Abstract

SummaryMalignant obstructive jaundice is associated with poor aerobic capacity. We measured oxygen consumption and oxygen extraction (arterial-venous oxygen content) in the legs of nine patients during cardiopulmonary exercise testing before pancreaticoduodenectomy. The median (IQR [range]) peak oxygen consumption was 67 (49-77 [32-84])% of predicted. Normal patterns of oxygen extraction were seen with increasing power towards lactate threshold. Near maximal oxygen extraction occurred at peak exercise. Femoral venous oxygen pressure and saturation exceeded baseline values whilst recovering from exercise. These findings suggest that peripheral oxygen extraction is normal during exercise in patients with malignant obstructive jaundice. The primary limitation in oxygen consumption is reduced oxygen delivery. We observed that patients with obstructive jaundice, presenting for major hepato-pancreatico-biliary surgery, were often unfit on cardiopulmonary exercise testing (CPET), with less than expected oxygen consumptions at peak exercise and at the lactate threshold. Reduced oxygen consumption may be due to reduced delivery or reduced extraction.Our patients did not have documented heart disease or abnormal resting trans-thoracic echocardiograms, but these do not exclude contractile dysfunction. Clinical studies have demonstrated that raised bilirubin is associated with raised endotoxin and inflammatory cytokine levels [1][2][3], as well as cardiovascular dysfunction characterised by hypovolaemia and reduced left ventricular systolic function [4,5]. Weber and Janicki demonstrated maximal peripheral oxygen extraction (> 70%) in patients with varying degrees of heart failure during exercise [6]. The authors demonstrated that reduced cardiac output was the primary cause of reduced aerobic capacity rather than impaired oxygen extraction. Stringer et al. showed that femoral venous oxygen saturation continues to fall after the lactate threshold but without a fall in femoral venous oxygen pressure, due to the rightshift of the haemoglobin dissociation curve in response to metabolic acidosis [7]. These changes represent normal microcirculatory responses to reduced oxygen delivery.Resuscitated septic patients have increased cardiac output, increased oxygen delivery and increased oxygen consumption [8][9][10]. However, the increase in oxygen delivery exceeds the increase in oxygen consumption, due to decreased oxygen extraction (the arterial -venous difference in oxygen content). 32© 2013 The Association of Anaesthetists of Great Britain and Ireland Anaesthesia 2014Anaesthesia , 69, 32-36 doi:10.1111 We hypothesised that poor exercise capacity in patients with obstructive jaundice was, like in septic patients, secondary to reduced oxygen extraction and a normal or raised cardiac output. MethodsThe Institutional and regional ethics committee approved the recruitment of 10 patients to this invasive pilot study. All participants provided written informed consent.We included patients eligible for pancreaticoduodenectomy, with el...

The Impact of Prehabilitation on Patient Outcomes in Hepatobiliary, Colorectal, and Upper Gastrointestinal Cancer Surgery

“…Due to the variability in exercise types, frequency, and duration it was not possible to group cancer types together to arrive at a combined effect for functional capacity. This is pertinent in cases where physiological/biological differences may affect the response to prehabilitation strategies 51,52 as well as the effect of neoadjuvant chemotherapy 53 , long/short course chemoradiation 54 , and pre-operative jaundice 55 .…”

“…This is pertinent in cases where physiological/biological differences may affect the response to prehabilitation strategies 51,52 as well as the effect of neoadjuvant chemotherapy, 53 long/short course chemoradiation, 54 and preoperative jaundice. 55 Prehabilitation interventions spanned from as little as 1 week 44 to a maximum of 6 weeks. 19 Interestingly, in this metaanalysis, there was no statistically significant relationships between the duration of prehabilitation and the improvement in patient outcomes.…”

Response to the Comment on “The Impact of Prehabilitation on Patient Outcomes in Hepatobiliary, Colorectal and Upper Gastrointestinal Cancer Surgery: A PRISMA-Accordant Meta-analysis”

“…Different cancers may exert different physiological effects in the same way that jaundiced patients with malignant biliary obstruction 6 or anemic patients 7 with colorectal cancer may perform poorly on cardiopulmonary exercise testing (CPET). This idea suggests that prehabilitation might not be a “one size fits all" strategy and may have to be tailored to suit the cancer type.…”