Biomaterial Database

Changes in hemodynamic variables during hypothermic cardiopulmonary bypass. Effects of flow rate, flow character, and arterial pH. 1990

R P Alston, and L Murray, and A D McLaren

Department of Anaesthesia, University of Glasgow, Scotland.

During hypothermic cardiopulmonary bypass, the effects on hemodynamic variables of alternating pump flow rate between 1.5 and 2.0 L.min-1.m-2, flow character between nonpulsatile and pulsatile perfusion, and acid-base management between pH- and alpha-stat control were studied in a crossover factorial experiment. Twenty-four patients who were undergoing elective coronary artery bypass grafting were studied during stable hypothermic (27 degrees to 29 degrees C) cardiopulmonary bypass. A minimum of two (when time allowed, three) consecutive 10-minute periods (period 1, 2, or 3) were investigated. Only stage of the study period during cardiopulmonary bypass, flow rate, and interaction between stage and acid-base management were found to have significant effects on mean arterial pressure. In all patients, there were average increases in mean arterial pressure from period 1 to period 2 of 9.4 (95% confidence interval 5.8, 13.0) mm Hg, from period 2 to period 3 of 6.3 (95% confidence interval 1.2, 11.4) mm Hg, and from period 1 to period 3 of 15.7 (95% confidence interval 10.6, 20.9) mm Hg. At 2.0 L.min-1.m-2, mean arterial pressure was 7.2 (95% confidence interval 1.6, 12.9) mm Hg higher than at 1.5 L.min-1.m-2. Peripheral vascular resistance was significantly affected only by stage and flow rate. There were, in all patients, mean increases in peripheral vascular resistance from period 1 to period 2 of 239 (95% confidence interval 135, 343) dynes.sec.cm-5, from period 2 to period 3 of 85 (-64, 234) dynes.sec.cm-5, and from period 1 to period 3 of 324 (95% confidence interval 175, 473) dynes.sec.cm-5. At 1.5 L.min-1.m-2, the peripheral vascular resistance was 316 (95% confidence interval 152, 480) dynes.sec.cm-5 higher than at 2.0 L.min-1.m-2. Alteration in flow rate, but not flow character or arterial pH, had a significant effect on peripheral vascular resistance. It is hypothesized that the increase in peripheral vascular resistance during the course of cardiopulmonary bypass results from an active capillary mechanism, whereas the increase that is associated with reduction in flow rate reflects a passive mechanism. The increase in peripheral vascular resistance with decrease in flow rate indicates impaired tissue perfusion, unlike that occurring with stage.

UI	MeSH Term	Description	Entries
D007036	Hypothermia, Induced	Abnormally low BODY TEMPERATURE that is intentionally induced in warm-blooded animals by artificial means. In humans, mild or moderate hypothermia has been used to reduce tissue damages, particularly after cardiac or spinal cord injuries and during subsequent surgeries.	Induced Hypothermia,Mild Hypothermia, Induced,Moderate Hypothermia, Induced,Targeted Temperature Management,Therapeutic Hypothermia,Hypothermia, Therapeutic,Induced Mild Hypothermia,Induced Mild Hypothermias,Induced Moderate Hypothermia,Induced Moderate Hypothermias,Mild Hypothermias, Induced,Moderate Hypothermias, Induced,Targeted Temperature Managements
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D001794	Blood Pressure	PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.	Systolic Pressure,Diastolic Pressure,Pulse Pressure,Pressure, Blood,Pressure, Diastolic,Pressure, Pulse,Pressure, Systolic,Pressures, Systolic
D001831	Body Temperature	The measure of the level of heat of a human or animal.	Organ Temperature,Body Temperatures,Organ Temperatures,Temperature, Body,Temperature, Organ,Temperatures, Body,Temperatures, Organ
D002315	Cardiopulmonary Bypass	Diversion of the flow of blood from the entrance of the right atrium directly to the aorta (or femoral artery) via an oxygenator thus bypassing both the heart and lungs.	Heart-Lung Bypass,Bypass, Cardiopulmonary,Bypass, Heart-Lung,Bypasses, Cardiopulmonary,Bypasses, Heart-Lung,Cardiopulmonary Bypasses,Heart Lung Bypass,Heart-Lung Bypasses
D002496	Central Venous Pressure	The blood pressure in the central large VEINS of the body. It is distinguished from peripheral venous pressure which occurs in an extremity.	Venous Pressure, Central,Central Venous Pressures,Pressure, Central Venous,Pressures, Central Venous,Venous Pressures, Central
D006400	Hematocrit	The volume of packed RED BLOOD CELLS in a blood specimen. The volume is measured by centrifugation in a tube with graduated markings, or with automated blood cell counters. It is an indicator of erythrocyte status in disease. For example, ANEMIA shows a low value; POLYCYTHEMIA, a high value.	Erythrocyte Volume, Packed,Packed Red-Cell Volume,Erythrocyte Volumes, Packed,Hematocrits,Packed Erythrocyte Volume,Packed Erythrocyte Volumes,Packed Red Cell Volume,Packed Red-Cell Volumes,Red-Cell Volume, Packed,Red-Cell Volumes, Packed,Volume, Packed Erythrocyte,Volume, Packed Red-Cell,Volumes, Packed Erythrocyte,Volumes, Packed Red-Cell
D006439	Hemodynamics	The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.	Hemodynamic
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations