Critical care medicine
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Critical care medicine · Nov 1979
Extrapulmonary factors influencing the ratio of arterial oxygen tension to inspired oxygen concentration in burn patients.
The ratio of arterial oxygen tension to inspired oxygen concentration (PaO2/FIO2) as an index of respiratory function was evaluated in 22 patients with body surface area burns of 15--80%. These results indicate that this ratio is limited in its applicability because extrapulmonary factors, such as cardiac output, oxygen consumption, and arterial oxygen content, can affect this index by alterations in the amount of venous desaturation. Useful estimates of intrapulmonary right to left shunt (Qs/Qt) from PaO2/FIO2 were obtained only when arteriovenous oxygen content differences (avDO2) were between 3--5 ml/dl. ⋯ Blood gases from central venous catheters did not mirror changes in true mixed venous blood and, thus, can lead to erroneous estimations of Qs/Qt. Rational therapy of reduced arterial oxygen saturation requires measurement of both extra- and intrapulmonary factors contributing to arterial desaturation. Measurement of PaO2/FIO2 alone will not estimate these factors.
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A Loosko MK2 ventilator has been modified to provide IMV in newborns. IMV rate can be varied from 3-60/min. The minimum inspiration period can be theoretically as low as 0.1 sec. This modification in neonatal mechanical ventilation has been shown to be economically feasible.
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Critical care medicine · Oct 1979
Comparative StudyOxygen consumption and recovery from surgical shock in rats: a comparison of the efficacy of different plasma substitutes.
Shock was induced in 537 rats by exteriorization of the intestines and occlusion of the superior mesenteric circulation for 1 hour. After 1 hour of this intestinal ischemia shock, oxygen consumption (VO2) decreased to half of the preexperimental values. When no infusion was given, the survival rate at 24 hours was 22%; this was correlated with the degree of restoration of VO2 at 1 hour after shock. ⋯ With increasing doses of colloids, both VO2 and survival rate increased; the optimal effect was at the dose of 2 g/kg body weight. When no other therapy was given, colloids at concentrations of 3.5 or 6% solutions had a better effect on survival than the 10% solution. Colloids were more effective than Ringer's acetate when the latter was given in the same volume and up to three times the volume of the colloids.
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Critical care medicine · Aug 1979
Case ReportsA simple technique for managing a bronchopleural fistula while maintaining positive pressure ventilation.
The development of a bronchopleural fistula (BPF) is an infrequent, but potentially devastating complication of positive pressure ventilation. A case report is detailed in which a BPF arose in a patient on controlled ventilation with a PEEP of 22 cm H2O. Within 12 hours, fistula flow was continuous and accounted for 75% of the delivered tidal volume. ⋯ Conventional treatment methods were unsuccessful, and a system was constructed for adding controlled levels of positive pressure ot the pleural space on the side of the BPF. By decreasing the expiratory transpulmonary pressure difference (PEEP minus pleural pressure), the fistula leak was greatly decreased, and PEEP and oxygenation were stabilized. This system can be rapidly constructed at the bedside with equipment routinely available in most hospitals and offers the ability to adjust the expiratory transpulmonary pressure, lung volume, and BPF flow while maintaining positive pressure ventilation with PEEP.
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The medical records of 21 patients with smoke inhalation admitted to a medical ICU (MICU) were reviewed. Of 21 patients, 6 (29%) died. Of 21 patients, 13 (62%) had facial burns and 11 of the 13 (85%) later developed pneumonia. ⋯ The authors conclude that the presence of facial burns is associated with the later development of pneumonia in a high percentage of cases. Pneumonia contributes significantly to the high mortality rate. The need for ventilatory assistance in smoke inhalation patients is associated with a poor prognosis.