Oxygen utilisation in patients on prolonged parenteral nutrition; a case-controlled study

Area of Science:

• Cardiology
• Pulmonology
• Metabolic Medicine

Background:

• Parenteral nutrition (PN) deficient in mitochondrial substrates and thiamine can cause acidosis.
• Fatigue in intestinal failure (IF) patients on PN may indicate impaired oxidative metabolism.
• This study investigated oxygen utilization in well-nourished IF patients receiving long-term PN.

Purpose of the Study:

• To assess oxygen utilization in patients with intestinal failure (IF) on long-term parenteral nutrition (PN).
• To compare cardiopulmonary exercise test (CPET) variables between IF patients on PN and healthy controls.
• To explore potential causes of fatigue in IF patients on PN.

Main Methods:

• Retrospective analysis of IF patients (cases) and matched controls from 2010-2019.
• Cardiopulmonary exercise testing (CPET) measured peak oxygen consumption (VO2 peak), anaerobic threshold (AT), and ventilatory efficiency (VE/VCO2).
• Patients were matched for age, gender, beta-blocker use, and p-POSSUM score; sepsis and malignancy were excluded.

Main Results:

• 31 IF patients and 62 controls were comparable in age, p-POSSUM, gender, smoking, beta-blocker, and steroid use.
• IF patients on PN were adequately nourished.
• No significant differences were observed in VO2 peak, AT, or VE/VCO2 between IF patients and controls.

Conclusions:

• Apparently well-nourished IF patients on PN exhibit normal oxygen utilization.
• Fatigue in this patient group likely arises from causes other than suboptimal oxidative metabolism.
• Further studies are needed to determine CPET's utility in assessing perioperative risk for IF patients on PN.