PD1051 - RESPIRATORY QUOTIENT AS A CLINICAL INDICATOR OF ANABOLIC READINESS IN MALNOURISHED PATIENTS AWAITING MAJOR SURGERY

PD1051

RESPIRATORY QUOTIENT AS A CLINICAL INDICATOR OF ANABOLIC READINESS IN MALNOURISHED PATIENTS AWAITING MAJOR SURGERY

A. Chehal^1,*, P. Skorepa^1,2, J. Visek¹, P. Navratil³, L. Sobotka¹, O. Sobotka^1,2

¹3rd Department of Internal Medicine – Metabolic Care and Gerontology, University Hospital in Hradec Kralove, ²Department of Military Internal Medicine and Military Hygiene, University of Defence, Military Faculty of Medicine, ³Department of Urology, University Hospital in Hradec Kralove, Hradec Kralove, Czech Republic

Rationale: Patients awaiting major abdominal or urological surgeries often suffer from malnutrition, making targeted prehabilitation crucial to reduce the risk of postoperative complications. While conventional mixed parenteral nutrition (PN) is standard during prehabilitation, surgical stress and tissue repair demand significant reducing equivalents, suggesting that a high-carbohydrate approach may better promote anabolism.

Methods: This preliminary study evaluated patients undergoing a 14-day prehabilitation program. Nutritional targets were individualized via indirect calorimetry: energy target was set to 1.3 × resting energy expenditure (REE) and proteins to 1.5 g/kg/day. Patients received non-protein energy either exclusively from glucose or from conventional mixed PN (1:2 fat-to-carbohydrate ratio). Metabolic response was monitored via indirect calorimetry and nitrogen balance, body composition assessed by in-body and BWA 2.0 analysis before and after prehabilitation.

Results: Both nutritional regimens led to increased muscle mass of patients after prehabilitation. The glucose-only group demonstrated a distinct metabolic advantage, achieving a substantially higher mean nitrogen balance (~8.5 g/day vs. ~2.0 g/day for mixed PN). Respiratory quotient (RQ) trajectories steadily approached 1.0 in the glucose cohort but remained lower in the mixed group. Regression analyses revealed positive correlations between nitrogen balance and overall RQ, total caloric/protein intake, and notably, the carbohydrate-to-REE ratio.

Conclusion: Purely glucose-based PN during surgical prehabilitation yields a more positive nitrogen balance and higher RQ than conventional mixed regimens. These findings suggest elevated RQ serves as an effective clinical marker of anabolism, reflecting the body's enhanced ability to incorporate dietary protein prior to surgery.

Disclosure of Interest: None declared