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Biomedical subjects

R C Kahn

Publications and source records attributed to R C Kahn.

29 records · Page 2Linked to original sources
PubMed1980

Evaluation of an "in vivo" PaO2 and PaCO2 monitor in the management of respiratory failure.

A commercially available gas-chromatograph (Sentorr Gas Analyzer, Ohio Medical Products, Madison, WI) was tested, featuring continuous measurement of in vivo PaO2 and PaCO2 by means of a thin, heparin-coated catheter, inserted through an indwelling arterial line. Gas tensions are displayed every 4 min. The probes had a tendency to break rather easily, and a considerable proportion of them was faulty. We measured 105 paired determinations of blood gases obtained from patients in respiratory failure requiring mechanical ventilation with a Corning IL 175 Analyzer and displayed by the Sentorr Gas Analyzer. A high correlation (p < 0.01) existed between the two sets of values, but an estimated error of 10-20% was found in the Sentorr data. After modifications of the respirator, changes of displayed values were already notable after 4 min and 90% completed by 8-12 min. The use of this device enabled us to considerably accelerate decision-making in the management of respiratory failure. Although techology still necessitates improvements, before widespread use of in vivo monitoring of PaO2 and PaCO2 is advisable, the concept has significant clinical potential and may represent a major advance in the management of respiratory failure.

Carbon Dioxide↗
PubMed1980

Pulmonary venous admixture during mechanical ventilation with varying FIO2 and PEEP.

Many authors have indicated that high FIO2 (0.75-1.0) ventilation may increase pulmonary venous admixture. Reabsorption atelectasis is supposedly responsible for this adverse effect. The authors attempted to determine if increasing PEEP during high FIO2 ventilation could eliminate the detrimental influence of the latter. In 17 patients in respiratory failure, hemodynamic and respiratory variables were measured during ventilation with FIO2 0.50, 0.75, and 1.0 and PEEP varying from -3 to +5 cm H2O from baseline. Before exposure to FIO2 > 0.75, addition of PEEP resulted in a decrease of Qs/Qt from a mean of 26.6-21.9%. After exposure to FIO2 0.75-1.0, Qs/Qt remained at levels not different from baseline, even when PEEP 8 cm H2O above baseline was added. The authors conclude that ventilation with high FIO2 is not useful in determining Qs/Qt, and may prevent the improvement in pulmonary venous admixture associated with PEEP therapy.

Blood Gas Analysis↗
PubMed1980

Prazosin in acute anthracyclene cardiomyopathy.

A 32-year-old woman with a 14-month history of acute lymphoblastic leukemia received 300 mg/sq m of doxorubicin. Shortly after the last course of therapy, congestive failure developed that was attributed to anthracyclene cardiomyopathy. Three weeks later, an acute septic episode was complicated by hypotension and low cardiac output. Adequate blood pressure and cardiac output were restored with a combined intravenous infusion of dopamine hydrochloride and nitroglycerine. Within 24 hours, oral therapy with prazosin and digitalis was initiated, and two days later, the intravenous infusions could be discontinued. Acute anthracyclene cardiomyopathy can be successfully treated with a combination of oral inotropic and vasodilating agents.

Adult↗
PubMed1979

Unexpected giant "V" waves during pulmonary artery catheterization.

Two cases of catheterization of the pulmonary artery, in which the hemodynamic findings were very different from the initial clinical diagnosis, are presented. The importance of verifying the adequate position and motion of the pulomonary artery catheters with two consecutive chest x-rays is discussed. In particular, attention is brought to the possible misinterpretation that occurs in patients with very elevated pulmonary artery mean pressure.

Blood Pressure↗
PubMed1978

Adverse effects of calcium administration. Report of two cases.

Calcium chloride, 7 mg/kg, and calcium gluconate, 20 mg/kg, were administered to patients with low or low-normal levels of serum ionized calcium. Both patients had low blood pressure and cardiac index, and did not respond to digitalis, volume expansion, and beta-adrenergic stimulation with dopamine. Administration of calcium rapid increase of serum ionized calcium levels, decrease of serum potassium levels, and development of severe cardiac arrhythmias. Atrioventricular dissociation and further fall of cardiac index and blood pressure were common features of both cases. Administration of exogenous calcium can cause severe complications, even when theoretically indicated.

Adult↗
PubMedDate not supplied

Long-term infusion of sodium thiopental: hemodynamic and respiratory effects.

To establish the possible advantages of ultrashort acting barbiturates administered in continuous infusion as the only sedative agent for mechanically ventilated patients, sodium thiopental was given to 30 subjects for periods ranging from 2--14 days. Plasma levels were maintained at approximately 15 microgram/ml, using both laboratory determinations and clinical judgment. This technique proved effective for patients requiring either controlled ventilation or intermittent mandatory ventilation. None of the hemodynamic and respiratory variables studied was significantly altered during the infusion, with the exception of decreased heart rates. In view of these results, the technique is considered both expedient and safe for prolonged sedation of patients requiring ventilatory support.

Clinical Trials as Topic↗
PubMedDate not supplied

Unusual complications during pulmonary artery catheterization.

Two unusual complications, encountered during pulmonary artery catheterization, are described. In both cases the catheter had been introduced percutaneously with the Seldinger technique. Inadvertent entry of the right pleural space occured in one case in which the catheter had been inserted into the internal jugular vein through a low cervical approach. The second complication was separation of the shaft of the introducer from the hub, with consequent risk of embolization. Possible means of preventing and treating these complications are discussed.

Adolescent↗
PubMedDate not supplied

Rapid volume expansion in patients with interstitial lung diseases.

Rapid administration of intravascular volume expanders is often necessary during anesthesia. Significant controversy still exists on the relative values of different volume expanders. Fifteen hypoxemic patients (Pao2 less than 70 torr on room air) were studied preoperatively. They were randomized into three groups. One group received 1.5 ml/kg of 25% salt-poor human albumin, a second group, 7 ml/kg of fresh frozen plasma; a third group, 7 ml/kg of 0.9% NaCl in water (normal saline). The infusions were given intravenously and completed in 20 minutes. Changes in hemodynamic pressures and flows, blood chemistries, and oxygen uptake and transport variables were studied. It was concluded that fresh frozen plasma afforded the greatest increase in cardiac output and oxygen availability with the least increase in left ventricular stroke work. Colloid osmotic pressure was more significantly increased by fresh frozen plasma than by salt-poor human albumin. Normal saline caused both a decrease in oxygen availability and colloid osmotic pressure. Pulmonary venous admixture increased to some extent in all patients receiving fresh frozen plasma or normal saline. In three patients, this increase was very marked and accompanied by severe arterial hypoxemia.

Adult↗