Hirofumi Takashima

Mixed venous oxygen saturation as a guide to tissue oxygenation and prognosis in patients with acute myocardial infarction

The relation of mixed venous oxygen saturation and the cardiac index to tissue oxygenation and prognosis was investigated in 119 patients with acute myocardial infarction. There was a positive correlation between mixed venous oxygen saturation and the cardiac index in 97 survivors and 22 nonsurvivors, but a significantly lower mixed venous oxygen saturation level at the same level of cardiac index was observed in nonsurvivors compared with survivors. Results of multivariate analysis with mixed venous oxygen saturation and the cardiac index indicated that only mixed venous oxygen saturation was significantly related to survival and to hyperlactacidemia. Oxygen delivery to tissues declined significantly in nonsurvivors because of a lower cardiac index and a lower hemoglobin concentration in these patients than in survivors. However, at the same level of oxygen delivery to tissues, nonsurvivors had a significantly higher rate of oxygen consumption leading to a correspondingly greater decrease in mixed venous oxygen saturation, suggesting that a greater increase in oxygen demand was also observed in nonsurvivors than in survivors. Thus mixed venous oxygen saturation after acute myocardial infarction is a better predictor of hyperlactacidemia and survival than the cardiac index, and this may be associated with an increased oxygen demand and an impaired oxygen transport system in seriously ill patients.

INCREASED EXTRAVASCULAR LUNG WATER IN PATIENTS WITH LOW PULMONARY ARTERY OCCLUSION PRESSURE AFTER ACUTE MYOCARDIAL INFARCTION

ObjectiveTo evaluate the clinical characteristics of increased extravascular lung water (EVLW) in patients with low pulmonary artery occlusion pressure (PAOP) in the early phase of acute myocardial infarction. DesignConsecutive sample for descriptions of the clinical features of medical disorders. SettingA general medicine group practice in a university hospital. PatientsSixteen patients with low PAOP (>18 mm Hg) on the initial measurement obtained within 12 hr of chest pain onset. Measurements and Main ResultsEVLW was measured by the thermal indocyanine green dye double-indicator dilution method. QRS score was obtained on hospital day 7 from the Selvesters QRS Scoring System. Eleven (69%) patients had increased EVLW >7 mL/kg despite low PAOP. EVLW had no significant correlation with PAOP and the difference between plasma colloid osmotic pressure and PAOP, but did have a significant correlation with pulmonary vascular resistance index (r2 = .31, p < .05), and QRS score (r2 = .45, p < .005). ConclusionLarger infarcts led to increased EVLW even with low PAOP, and the accumulation of increased EVLW around the small arterioles might have led to increased pulmonary vascular resistance. (Crit Care Med 1991; 19:21)

Oxygen delivery, oxygen consumption and hemoglobin-oxygen affinity in acute myocardial infarction

The interrelations of oxygen delivery (DO2), oxygen consumption (VO2) and hemoglobin-oxygen affinity assessed by P50 were investigated in 43 patients with acute myocardial infarction. As DO2 declined due to low cardiac output, a significant decrease in VO2 (r = 0.75, p less than 0.001) and a significant increase in P50 (r = -0.74, p less than 0.001) were observed. In the DO2 range between 300 and 450 ml/min/m2, in which the DO2 of 32 survivors and 11 nonsurvivors overlapped, the P50 of nonsurvivors was significantly higher than that of survivors (31.5 +/- 1.6 vs 27.9 +/- 1.5 torr, p less than 0.001), but there were no significant differences in any other oxygen transport variable. As a result of differences in P50, VO2 in this range was significantly higher in nonsurvivors compared to survivors (169 +/- 17 vs 148 +/- 13 ml/min/m2, p less than 0.001). These data suggest that a normal or increased VO2 alone does not ensure survival in patients with acute myocardial infarction, and increased P50 leads to an increase in VO2. Nevertheless, the interpretation of an increased P50 in patients with acute myocardial infarction must be made with caution, even with adequate DO2 and VO2, because it may imply a precarious oxygen transport/requirement balance in peripheral tissue and, hence, a fatal outcome.

Simultaneous measurement of α-human atrial natriuretic factor (hANF) and NH2-terminal fragment of pro-hANF in essential hypertension

A radioimmunoassay specific for the N-terminal fragment of prohuman atrial natriuretic factor (hANF) was established with the use of antiserum for pro-hANF (1-30). Plasma levels of alpha-hANF-like immunoreactivity (LI) and pro-hANF (1-30)-Ll in patients with severe hypertension who were receiving a normal sodium diet were 56 +/- 5 pg/ml and 2710 +/- 118 pg/ml, respectively; these levels were significantly higher than control values. Levels of these peptides in patients with mild hypertension were similar to those of control subjects. Mean blood pressure correlated closely with alpha-hANF-Ll levels (r = 0.56, p less than 0.001) and pro-hANF (1-30)-Ll levels (r = 0.66, p less than 0.001) in patients receiving a normal sodium diet. Plasma alpha-hANF-Ll and pro-hANF (1-30)-Ll levels were significantly decreased 3 days in mild hypertension and 7 days in severe hypertension after initiation of a low-sodium diet with a decrease in blood pressure as compared to the initial values. These results suggest that plasma N-terminal fragment levels are elevated in proportion to the degree of hypertension, and they can be reduced by means of effective antihypertensive treatment.

Acute pulmonary edema in patients with unstable angina: clinical profile and natural history

BackgroundPulmonary edema is an important manifestation of ischemic cardiac dysfunction, both in the presence and absence of myocardial infarction. However, the clinical characteristics and natural history of pulmonary edema with unstable angina have not been fully evaluated. MethodsOne hundred twenty patients admitted to our hospital within 6 hours from the onset of last chest pain were studied. Clinical features were reviewed from hospital charts and coronary angiography was performed in acute phase (33 patients) and in the late hospital phase (62 patients). The mean follow-up period was 26 months. Results: Pulmonary edema was present in 24 patients and was absent in 96 patients. The duration of chest pain was longer (P<0.01) and incidence of multivessel disease was higher (P<0.01) in patients with pulmonary edema than those without it. The total mortality rate in patients with pulmonary edema was higher that those without it (33% vs 3%; P<0.001). These data indicate that a large mass of ischemic myocardium could cause transient increase of left ventricular diastolic pressure to pulmonary edema level without infarction ever occurring. ConclusionsBecause of the high incidence of multivessel disease and the poor prognosis in patients with pulmonary edema in unstable angina, early and aggressive diagnostic efforts should be undertaken to exclude viable segments of myocardium in patients with unstable angina complicated by pulmonary edema.

Effect of atrial and ventricular activation interval on hemodynamics during atrioventricular and ventriculoatrial pacing : determination from pressure-volume loops in dogs

To determine the effect of relative timing of atrial and ventricular activation on hemodynamic indices, we evaluated pressure-volume loops during pacing at 160 beats/min with various atrioventricular intervals in dogs. End-systolic pressure, end-diastolic volume, and stroke volume were reduced during pacing at atrioventricular intervals of 0 ms, compared with 80 ms. These changes were more significant during pacing at atrioventricular intervals of -50 and -100 ms than at 0 ms. During tachycardia, the abnormal timing of atrial contraction leads to unfavorable hemodynamic change and the degree of the changes are determined by the ventriculoatrial activation interval.