Leon Stein

Cardiac arrest in the critically III: II. Hyperosmolal states following cardiac arrest

Abstract A hyperosmolal state was documented in 12 patients after cardiac resuscitation. Plasma osmolality was increased to levels which are regarded as potentially lethal on the basis of experimental and clinical studies. The hyperosmolal state was directly related to injection of Hypertonic sodium bicarbonate (7.5 per cent) in amounts ranging from 90 to 540 mOsm. All 12 patients died. On the basis of these observations, we recommend caution in using large amounts of hypertonic sodium bicarbonate for acute cardiac resuscitation. The routine and repetitive measurement of blood pH and carbon dioxide pressure, and measurement of plasma osmolality during the resuscitative period, are advised to guide the use of alkali in order to avoid the iatrogenic risk of fatal hyperosmolal states.

Pericarditis as a manifestation of histoplasmosis during two large urban outbreaks.

During two histoplasmosis outbreaks in Indianapolis 45 patients presented with pericarditis. The pericarditis occurred as a late complication in individual patients and during the outbreak. Risk factors for this complication included young age, immunocompetence, and male sex in persons between 20 and 39 years old. Intrathoracic adenopathy was present in 66% of cases. Since cultures were uniformly negative, including pericardial fluid or tissue from nine patients, serologic studies provided the basis for diagnosis. Although the course was usually benign, nine patients presented with tamponade and another with constrictive pericarditis. Prompt response to antiinflammatory medications and failure to identify H. capsulatum in the pericardial fluid or tissue support a noninfectious, inflammatory mechanism for this complication. Of 20 patients reexamined 1 year later, none had evidence of constriction but three had pericardial thickening by echocardiography. Histoplasmosis should be considered in patients with pericarditis from endemic areas, particularly when associated with intrathoracic adenopathy.

Increase in plasma norepinephrine during prazosin therapy for chronic congestive heart failure.

To investigate the mechanism of pharmacodynamic tolerance reported to occur during prazosin therapy of chronic congestive heart failure, we measured plasma norepinephrine, plasma epinephrine, plasma renin activity (PRA) and plasma aldosterone, as well as hemodynamics in eight patients with chronic congestive heart failure, functional class III and IV (NYHA), before and during 10 weeks of prazosin therapy. Initially, prazosin therapy produced significant hemodynamic improvement, but no significant changes were noted in norepinephrine, epinephrine, plasma renin activity or aldosterone. During ambulatory therapy, fluid retention developed in four patients, and three of them had symptoms or clinical evidence of congestive heart failure for which they required an increase in diuretic or prazosin therapy. Plasma norepinephrine levels for the whole group were significantly higher after four weeks of therapy (p less than 0.01). Repeat inpatient studies after 10 weeks showed a persistent hemodynamic response to prazosin in seven patients. One patient demonstrated complete hemodynamic tolerance whereas three others showed partial tolerance. In these four patients the cardiac output increased only to 3.78 +/ 1.17 liters/min compared to 5.04 +/- 2.11 liters/min during initial prazosin therapy. Plasma norepinephrine increased further and levels were significantly higher for the whole group than before prazosin therapy (p less than 0.05). No significant changes in epinephrine, plasma renin activity or aldosterone were demonstrated. This increase in plasma norepinephrine suggests that the sympathetic nervous system could be involved in the pharmacodynamic tolerance to prazosin therapy in congestive heart failure. Further studies are necessary to extend these results.

Myocardial Blood Flow in Man as Measured by a Coincidence Counting System and a Single Bolus of 84RbCl

Utilizing a coincidence counting system for the measurement of myocardial uptake of an 84-rubidium indicator, resting coronary blood flow (CBF) was measured in 33 normal subjects. The average CBF was 269 ± 61 ml/min/total heart. This represented 5.2 ± 1.6% of the simultaneous cardiac output. Fourteen normal subjects had resting and exercising CBF measurements. The change in CBF with exercise was statistically significant (0.005 > P > 0.001). The characteristics of the method are discussed in relationship to possible clinical applications for the measurement of CBF.

Symptom-limited arm exercise increases detection of ischemia during dipyridamole tomographic thallium stress testing in patients with coronary artery disease.

Exercise combined with dipyridamole during thallium stress testing in patients with coronary artery disease (CAD) increases the frequency of angina and ischemic ST changes in the electrocardiogram. Evidence for an increase in thallium abnormalities has been inconclusive. We prospectively examined 54 consecutive patients who underwent coronary angiography and tomographic thallium with dipyridamole (0.57 mg/kg) alone and combined with symptom-limited dynamic arm exercise. Most patients presented with a history of chest pain and 49 had angiographic evidence of significant coronary stenosis (50% diameter narrowing). Thallium abnormalities were scored blindly by consensus. The number of abnormal segments (total and ischemic) and indexes of left ventricular dysfunction, such as increased lung uptake or ischemic dilation, were compared in the 49 patients with CAD. During arm exercise more patients had evidence of ischemia (39 vs 30; p < 0.001), and the number of ischemic segments increased significantly from 1.3 +/- 1.5 to 2.5 +/- 2.2 (p < 0.001). There was also a significant increase in the indexes of left ventricular dysfunction, ischemic dilation (10 vs 4 patients; p < 0.03) and increased lung uptake (16 vs 5 patients; p < 0.001). Patients who exercised had increased thallium evidence of extent and severity of ischemia and more frequent indexes of left ventricular dysfunction. Thus, symptom-limited arm exercise improves detection of extent and severity of ischemia in patients with CAD undergoing dipyridamole thallium stress testing.

Myocardial Blood Flow in Man Measured by a Coincidence Counting System and a Single Bolus of 84Ribidium Chloride

Using a coincidence counting system and a single bolus injection of 84RbCl, the effect of sublingual nitroglycerin (0.6 mg) on myocardial blood flow (MBF) in normal human subjects was studied. Concomitant pressure time per minute work of the heart was calculated as the product of heart rate, systolic mean pressure, and systolic ejection period. Seventeen subjects were studied. In seven, repeat measurements were made 3 minutes after administration of nitroglycerin and in 10 subjects 10 minutes after the drug was given.There was no predictable direction of change in myocardial blood flow, seven subjects showing an increase and 10 subjects a decrease. There was a highly significant correlation (P<0.001), however, between the changed in myocardial blood flow and concomitant pressure time. It is concluded that sublingual nitroglycerin does not a priori increase myocardial blood flow in normal man at 3 or 10 minutes; rather, the changes may be related to changes in myocardial oxygen requirements. It would appear, thus, that nitroglycerin does not alter the autoregulatory vessels of the heart.

Hyperosmolal crisis following infusion of hypertonic sodium chloride for purposes of therapeutic abortion

Abstract Transabdominal injection of 250 ml of 23.4 per cent sodium chloride for purposes of inducing abortion during the 18th week of gestation in a 15 year old girl was followed by acute cerebral, cardiac, respiratory and renal failure. Widespread organic damage was attributable to intravascular injection or rapid intravascular absorption of the hypertonic sodium chloride, with consequent expansion of intravascular volume and cellular dehydration. A marked reduction in colloid osmotic pressure was associated with persistent pulmonary edema after reversal of congestive heart failure. A favorable course followed volume repletion, digitalization, administration of corticosteroids, mechanical ventilation and peritoneal dialysis. Except for a minor cerebral deficit that persisted for approximately three months, there was no residual organic impairment.

RELATIONSHIP BETWEEN PULMONARY HEMODYNAMICS AND ARTERIAL pH AND CARBON DIOXIDE TENSION IN CRITICALLY ILL PATIENTS

To ascertain the clinical significance of derangements in arterial pH and arterial carbon dioxide tension (PaCO2) in modifying pulmonary arterial pressures and pulmonary vascular resistance in critically ill patients, the relationship between these two sets of variables was evaluated in 75 patients. No significant differences in pulmonary hemodynamic values were found among patients with acidemia, a normal pH, or alkalemia, even at extreme pH values; and there was no consistent relationship between PaCO2 and each of the pulmonary hemodynamic measurements. In patients who initially had a normal pH but subsequently developed acidemia or alkalemia, there was also no significant correlation between changes in pH and pulmonary hemodynamic values. We conclude that abnormalities of pulmonary hemodynamic values in seriously ill patients are usually due to factors other than acid-base derangements. Of practical importance is the observation that the predictability of the pulmonary arterial wedge pressure from the pulmonary arterial diastolic pressure is not invalidated by acid-base disturbances.