Critical care medicine
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Critical care medicine · Aug 1993
Comparative StudyPressure-controlled ventilation versus controlled mechanical ventilation with decelerating inspiratory flow.
To ascertain whether pressure-controlled ventilation offers any advantage with respect to conventional controlled mechanical ventilation with decelerating flow. ⋯ Our study failed to demonstrate any important difference between pressure-controlled ventilation and controlled mechanical ventilation with decelerating inspiratory flow waveform. The differences in the airway pressures detected by the ventilator are spurious and are due to the place (inspiratory line) where these pressures were measured. The difference between the peak pressure measured in the orotracheal tube has statistical, but not clinical, value and is lower in controlled mechanical ventilation. Based on the limited number of variables we studied and unless the tendency indicated in the quasi-static compliance is demonstrated in the future, we do not believe that pressure-controlled ventilation contributes any uniqueness to the theory or practice of mechanical ventilation.
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Critical care medicine · Aug 1993
Comparative StudyA new ventilation inhomogeneity index from multiple breath indicator gas washout tests in mechanically ventilated patients.
a) To determine the validity of a new method to analyze indicator gas washout tests on mechanically ventilated patients. This method takes into account the difference between the end-expiratory gas fraction and the mean gas fraction in the lung and provides the end-expiratory lung volume and a new index of ventilation inhomogeneity called volumes regression index. b) To determine the validity of this index as a predictor of chronic obstructive pulmonary disease. c) To compare this index with the moment ratio index and Becklake index. ⋯ The proposed technique provides a means for accurate measurement of the end-expiratory lung volume and the amount of ventilation inhomogeneity in mechanically ventilated intensive care unit patients.
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Critical care medicine · Aug 1993
Comparative StudyInfrared tympanic thermometry in the pediatric intensive care unit.
To determine the performance of two different commercially available, noncontact infrared tympanic thermometers in predicting core body temperature as measured by pulmonary artery catheters in pediatric intensive care unit (ICU) patients. The performance of the tympanic thermometers was compared with the performance of an indwelling rectal probe and digital axillary temperature determinations. ⋯ In a pediatric ICU population, rectal probes reflect core temperature better than axillary determinations and both infrared tympanic models estimated core body temperature better than digital axillary temperature. One of the tympanic systems (Thermoscan Pro-1 infrared tympanic thermometer) performed in a similar way to the indwelling rectal probes and may be used to estimate core temperature in situations where a pulmonary artery catheter is not in place. The other test tympanic system (First Temp) had greater variability than the rectal probes.
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Critical care medicine · Aug 1993
Comparative StudyCentrifugal ventricular assist device for support of the failing heart after cardiac surgery.
To determine the morbidity and mortality associated with use of centrifugal ventricular assist devices for postcardiotomy cardiogenic shock and to determine factors that might influence outcome and thus, aid in patient selection. ⋯ These results document a low incidence of ventricular assist device use in a surgical practice that employs a relatively simple method of myocardial protection. When postcardiotomy ventricular assistance was necessary, a centrifugal pump was used and successful outcome and satisfactory long-term results were possible in nearly one third of patients. Ventricular assistance for cardiac failure after transplantation was associated with improved survival. Older age is a relative contraindication to mechanical ventricular assistance.
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Critical care medicine · Aug 1993
Active core rewarming in neurologic, hypothermic patients: effects on oxygen-related variables.
To determine in hypothermic patients if a) the decrease in oxygen consumption (VO2) is exclusively dependent on the decrease in metabolic rate, or b) as a consequence of the greater hemoglobin affinity for oxygen, hypothermic tissues have impaired oxygen extraction. ⋯ These data show that VO2 was reduced to half of normal values during hypothermia. Active core rewarming produced an average 4.5% increase in VO2 per 1 degree C that was characterized by the wide variation observed in this metabolic response between different patients and for individual cases. Despite the rightward shift of P50 observed during rewarming (mainly due to the Bohr effect), no change was reflected on the oxygen extraction ratio.