Intra-abdominal and abdominal perfusion pressure in patients undergoing coronary artery bypass graft surgery

In 2006, the International Conference of Experts on Intra-abdominal Hypertension defined abdominal perfusion pressure (APP) as the difference between mean arterial pressure (MAP) and intra-abdominal pressure (IAP).The aim of the study was to analyse changes in IAP and APP in patients undergoing elective coronary artery bypass grafting (CABG).

Fifty patients undergoing CABG with extracorporeal circulation (ECC) and normovolemic haemodilution (NH) under general anaesthesia were studied. IAP and APP were measured during CABG and in the early postoperative period. Changes in IAP and APP were analysed according to degree of normovolemic haemodilution, age, body weight, body mass index (BMI), duration of anaesthesia, surgery, ECC, aorta clamping and other haemodynamic parameters.

The induction of anaesthesia decreased IAP. Extracorporeal circulation resulted in IAP elevation, which was dependent on the degree of blood dilution. At any time point of the postoperative period IAP higher than 12 mmHg was noted in 22 patients (44%). Abdominal perfusion pressure decreased during ECC and on the morning of the first postoperative day. Intra-abdominal pressure strongly correlated with BMI and central venous pressure. The correlation between IAP and APP and other haemodynamic parameters was poor.

1) The induction of anaesthesia decreased IAP. 2) ECC resulted in an increase in IAP. 3) IAP increased in 44% of patients. 4) IAP strongly correlated with BMI and central venous pressure. 5) CABG with ECC resulted in a decrease in APP. 6) Changes in APP strongly correlated with MAP and poorly correlated with other haemodynamic parameters. 7) The changes in APP demonstrated a double-phase character.