Critical care medicine
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Critical care medicine · Jul 1989
Cost and survival results of critical care regionalization for Medicare patients.
A ground-based mobile ICU, two medical evacuation helicopters, and a specially equipped fixed wing aircraft were utilized by a critical care transport team, staffed by a critical care physician, ICU nurse, critical care technologist, and respiratory therapist to facilitate regionalization of critical care services from small community hospitals to a central tertiary care facility. Survival, length of stay, age, actual hospital cost, and reimbursement were evaluated retrospectively for 81 Medicare patients transported by the team to a tertiary care facility during a 33-month period. ⋯ Average hospital cost per patient was $36,059.00, average Medicare reimbursement was $13,802.00, and average hospital loss was $22,256.00. We show that regionalization to tertiary care facilities can facilitate access to critical care technology, but the Medicare reimbursement system of diagnosis-related groups makes this concept financially prohibitive for the tertiary care hospital.
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Critical care medicine · Jul 1989
Comparative StudyAccuracy of delivered versus preset minute ventilation of portable emergency ventilators.
The accuracy of delivered minute volume (VE) ventilation of portable emergency ventilators (PEV) was evaluated. Five PEV from three manufacturers were adapted to an artificial lung for varying compliance and resistance. Each PEV was tested in the "no airmix" (pure oxygen) and "airmix" (approximately 60% oxygen) setting at different frequencies and VE. ⋯ Further investigation is needed before this prototype goes into production. Manufacturers should redefine predicted values or machine settings or indicate that use of these devices may produce results which are not in accordance with the machine settings. Until adjustments are made, ventilation should be monitored when possible by measurement of end-tidal PCO2 or systemic arterial blood gases.
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Critical care medicine · Jul 1989
Effect of lipopolysaccharide on intestinal intramucosal hydrogen ion concentration in pigs: evidence of gut ischemia in a normodynamic model of septic shock.
We tested the hypothesis that lipopolysaccharide (LPS) leads to an imbalance between mesenteric oxygen delivery (DO2) and gut metabolic demand for oxygen, even when cardiac index (CI) is within the normal range. Two groups of pentobarbital-anesthetized pigs (13 to 17 kg) were studied. The first group (LPS; n = 9) was infused over 20 min with Escherichia coli LPS (100 micrograms/kg) and resuscitated with normal saline (1.2 ml/kg.min). ⋯ SMA flow and mesenteric DO2 decreased significantly in the LPS group. Although mesenteric oxygen utilization was well preserved in both groups, ileal intramucosal [H+] was significantly higher in endotoxic animals. These data support the idea that mesenteric oxygen consumption is flow-limited in this clinically relevant porcine model of septic shock.
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Critical care medicine · Jul 1989
Comparative StudyAdditional work of breathing imposed by endotracheal tubes, breathing circuits, and intensive care ventilators.
A disadvantage of spontaneous breathing through an endotracheal tube (ETT) and connector attached to a breathing circuit and/or ventilator (breathing device) is an increase in the work of breathing. The work of breathing associated with ETT of 6 to 9-mm diameter and eight breathing devices was determined, using a lung simulator to mimic spontaneous inspiration at flow rates of 20 to 100 L/min and a tidal volume of 500 ml, at both zero end-expiratory pressure (ZEEP) and 10 cm H2O continuous positive airway pressure (CPAP). Work associated with the breathing devices alone (WCIR) ranged from -0.002 kg.m/L (Servo 900-C ventilator, 7-mm ETT, 20 L/min, ZEEP) to 0.1 kg.m/L (continuous flow circuit, 7-mm ETT, 100 L/min, CPAP), the latter representing 196% of the work of normal breathing. ⋯ This additional work imposed by the ETT varied considerably among devices. Spontaneous breathing through modern ventilators, circuits and ETT imposes a burden of increased work, most of which is associated with the presence of the ETT and connector. Whether this burden represents an impediment to the weaning patient, or has training value for the ultimate resumption of unassisted spontaneous ventilation, remains to be determined.
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Critical care medicine · Jul 1989
Comparative StudyComparison of recorded values from six pulse oximeters.
Recorded values (SpO2) of oxygen saturation from six noninvasive pulse oximeters were compared to each other and to the value from a cooximeter. Simultaneous measurements were obtained from each instrument in eight healthy nonsmoking volunteers rendered hypoxic greater than 70% SpO2. Functional arterial oxygen saturation (SaO2), fractional SaO2 (%HbO2), and percent fraction of carboxyhemoglobin (HbCO) and methemoglobin (MetHb) were determined by a cooximeter. ⋯ These results may indicate that, under normal dyshemoglobin levels, some pulse oximeters are calibrated to estimate SaO2 and others to estimate %HbO2. Since the pulse oximeter using two wavelengths cannot measure accurately %HbO2 or SaO2 in the presence of dyshemoglobin, SpO2 values would be independent from %HbO2 and SaO2. A standard calibration method for pulse oximeters should be established by the manufacturers.