Vito L

Myocardial depression during sepsis

The cardiac response to volume loading was evaluated in fifty severely septic patients. After a rapid infusion of albumin or whole blood the cardiac index (CI) and left ventricular stroke work index (LVSWI) were recorded as the pulmonary arterial wedge pressure (PAWP) increased. Initial values of PAWP, CI, and LVSWI were similar in both the nineteen surviving and thirty-one nonsurviving patients. Surviving patients, however, demonstrated greater increases in CI and LVSWI as PAWP rose. Nearly half of both patient groups developed decreases in CI and LVSWI as the PAWP continued to increase. These downslopes occurred at relatively low PAWP and are taken as evidence of an abnormality of myocardial function in both survivors and nonsurvivors. The lower upslope of the performance curves in nonsurvivors indicates myocardial depression or a negative inotropic effect. Cardiac ischemia, acute respiratory failure, and high affinity red cells were found to diminish the cardiac response to volume loading, whereas hepatic and renal failure were associated with a good CI and LVSWI response.

Transfusion of 2,3 DPG-Enriched Red Blood Cells to Improve Cardiac Function

Attempts were made to enhance oxygen availability in patients undergoing coronary artery bypass operations by transfusing red blood cells enriched in 2,3 diphosphoglycerate (2,3 DPG) to 150% of normal. In this study of 22 patients, 11 received red blood cells with high 2,3 DPG levels and 11 received red blood cells with 70% of normal 2,3 DPG levels (control). Immediately following cardiopulmonary bypass the 11 patients who received high 2,3 DPG red blood cells had a P50 value of 31.6 mm Hg; the value in control patients was 28.3 mm Hg (p less than 0.05). Oxygen consumption values were 135 and 106 ml/min/m2, respectively (p less than 0.05). Mixed venous oxygen tensions were similar in the two groups, but the arteriovenous content difference was higher in the high 2,3 DPG group (p less than 0.05). Cardiac indices increased significantly in response to a fluid load in the high 2,3 DPG group compared with controls at comparable filling pressures. We believe the improved myocardial performance in response to a fluid challenge is a result of increased oxygen availability.

Clinical applications of thermodilution cardiac output determinations

The pulmonary arterial catheter was shown to be safe and easily positioned in a group of 200 patients. Thermodilution cardiac output measurement was shown to be simple, rapid, and safe. The technic was as accurate as the simultaneously measured indocyanine green cardiac output, and more reproducible, particularly at high and low flows. The construction of myocardial performance curves during a fluid challenge is described. The value of these curves is guiding fluid, drug, and respirator therapy is illustrated by case presentations.

Response to intra-aortic balloon pumping☆

Abstract Mechanical circulatory assistance utilizing the intra-aortic balloon pump was employed sixty-five times in a series of sixty-three patients with the following clinical conditions: (1) cardiogenic shock after myocardial infarction, with subsequent medical management in fourteen patients; (2) cardiogenic shock after myocardial infarction with subsequent surgical management in four patients; (3) preinfarction angina syndrome in six patients; (4) septic shock in five patients; (5) postcardiotomy cardiogenic shock with dependence on cardiopulmonary bypass in twenty-six patients; (6) postcardiotomy cardiogenic shock during the recovery period in seven patients; (7) miscellaneous indications in three patients. Duration of assistance with intra-aortic balloon counterpulsation varied between 2 and 172 hours. Hemodynamic monitoring of arterial, central venous, pulmonary arterial, and left ventricular filling pressures was performed. Frequent measurements of cardiac output by a thermodilution technic with determination of cardiac index and left ventricular stroke work index in twenty patients provided an assessment of left ventricular function with and without intra-aortic balloon counterpulsation. Intra-aortic balloon counterpulsation produced effective assistance in fifty-four of sixty-five cases (83 per cent). In fifty-four patients in shock with low cardiac output, effective mechanical circulatory assistance with intra-aortic balloon counterpulsation was established in forty-six (85 per cent) as evidenced by reversal of the shock state. Cardiac index and left ventricular stroke work index were improved by intra-aortic balloon counterpulsation in most instances, particularly if left ventricular filling pressures were 15 to 20 mm Hg. There were thirty-two survivors (51 per cent).

Cardiac Output Measurement by Thermodilution during Cardiac Operations

Measurement of cardiac output by the thermodilution (COTD) technique through a flow-advanced pulmonary artery catheter is simple, reliable, and practical at the bedside. Rapid repeat determinations are possible, facilitating dynamic description of myocardial performance through construction of ventricular function curves. Replicate determinations of cardiac output indicate that the thermodilution method is more accurate than the indocyanine green technique. Examples of the clinical application of COTD in cardiac surgical patients are provided.