Visceral and Peripheral Tissue Perfusion after Cardiac Surgery

Abstract

Visceral and peripheral tissue perfusion and oxygenation were studied in ten patients in the early phase after coronary artery bypass grafting. Visceral perfusion was assessed indirectly, by determining gastric intramucosal pH. As parameters of peripheral tissue perfusion and oxygenation, subcutaneous tissue PO₂ (PscO₂), transcutaneous PO₂ (PtcO₂), PtcO₂ index (PtcO₂/PaO₂), laser-Doppler skin red-cell flux (RCF) and fingertip temperature (Tft) were recorded in the upper extremity. Central haemodynamics, rectal temperature and blood gases were also measured. The inspired oxygen concentration was maintained at 30 v/v%. Gastric intramucosal pH declined progressively during the first 3 hours in the intensive care unit, reached its minimum at 5 hours and thereafter slowly increased. The peripheral vascular bed was shut down on admission to the ICU, as indicated by low values of PscO₂, PtcO₂, PtCO₂ index, RCF and Tft. These parameters began to rise after the next 2–4 hours and peaked by the end of the 8-hour study period, indicating complete opening of the peripheral vascular bed.

Key Words:

• cardiac surgery
• haemodynamics
• visceral perfusion
• gastric intramucosal pH
• tissue oxygen tension
• transcutaneous oxygen tension
• laser-Doppler flowmetry
• skin temperature