[Clinical evaluation of hepatic blood flow and oxygen metabolism during thoracoabdominal aortic surgery using pulse dye-densitometry combined with hepatic venous oxygen saturation].
OBJECTIVE
There has been no report that pulse dye-densitometry (PDD), a novel non-invasive modality for monitoring hepatic blood flow (HBF), was applied during cardio-pulmonary bypass (CPB). We investigated weather PDD was useful to measure HBF during thoracoabdominal aortic surgery using partial CPB. Furthermore, HBF and hepatic metabolism were assessed during selective visceral perfusion or shunt using PDD, hepatic venous oxygen saturation (ShO2), and analysis of hepatic metabolic products.


METHODS
A prospective study was carried out in eight patients who underwent thoracoabdominal aortic surgery from April 1998 to October 1999. Operative adjuncts were partial CPB with mild hypothermia in six (femoral veno-arterial bypass: FF group) and deep hypothermic circulatory arrest in two (DHCA group). Measurements were performed at following five time points; just before initiating CPB, just after establishing CPB, during selective visceral perfusion, during selective visceral shunt, and just after weaning CPB.


RESULTS
Plasma clearance rate of indocyanine green measured by PDD well correlated with that obtained by in vitro spectrophotometry (p < 0.0001, R2 = 0.644). PDD demonstrated that decreased IIBF during selective visceral perfusion or shunt was well compensated by increased hepatic oxygen extraction rate in FF group and reduced oxygen consumption in DHCA group. Lactic acid extraction ratio and arterial ketone body ratio also decreased during this period. ShO2 during selective visceral shunt correlated with systemic systolic arterial pressure (SAP), and it showed a marked decrease under 20% when SAP was below 80 mmHg. Postoperative time course of serum total bilirubin and alanine aminotransferase of almost patients were within acceptable limits except the patient who required large amount of homologous blood transfusion.


CONCLUSIONS
PDD proved to be a useful modality that enabled non-invasive monitoring of HBF even during partial CPB. Decreased HBF during selective visceral perfusion or shunt in thoracoabdominal aortic surgery was within physiological compensation, which led us conclude that it might be effective adjuncts, for visceral organ protection.
Kunihara
T
T
Department of Cardiovascular Surgery, Hokkaido University, School of Medicine, Sapporo, Japan.
Wakamatsu
Y
Y
Adachi
A
A
Koyama
M
M
Shiiya
N
N
Sasaki
S
S
Murashita
T
T
Matsui
Y
Y
Yasuda
K
K
D000328:Adult; D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery*; D017545:Aortic Aneurysm, Thoracic / Q000601:surgery*; D002315:Cardiopulmonary Bypass; D004396:Coloring Agents; D003720:Densitometry / Q000379:methods; D005260:Female; D006503:Hepatic Veins; D006801:Humans; D007208:Indocyanine Green; D008099:Liver / Q000378:metabolism; D008102:Liver Circulation; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D011446:Prospective Studies
D004396:Coloring Agents; D007208:Indocyanine Green; D010100:Oxygen