Biomedical instrumentation & technology / Association for the Advancement of Medical Instrumentation
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Biomed Instrum Technol · Jul 1999
A closed rebreathing system for dose maintenance during Partial Liquid Ventilation.
Partial Liquid Ventilation (PLV), a treatment for acute respiratory failure in which the lungs are filled, either partially or to functional residual capacity (FRC), with perfluorochemical (PFC) liquid while the patient is on mechanical gas ventilation, has progressed to clinical trials using the PFC perflubron (PFB). Because gas expired during PLV is laden with PFB vapor, PFB is lost via evaporation, which increases dose consumption and necessitates periodic redosing. A device has been developed to minimize evaporative loss by confining PFC vapor to a gas volume breathed by the patient, which is isolated from the ventilator. ⋯ It is recommended that flow, pressure, O2, and CO2 levels be monitored at the patient "Y," i.e., the proximal end of the endotracheal tube. Performance data from both in-vitro experiments and in-vivo PLV experiments in pigs are presented. The authors conclude that with the closed rebreathing system, the dose can be safely maintained with fewer redosing procedures, and an approximately 90% savings in dose is achieved.
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Biomed Instrum Technol · May 1999
Multifactorial analysis of exchanger efficiency and liquid conservation during perfluorochemical liquid-assisted ventilation.
Liquid-assisted ventilation (LAV) of the lung with perfluorochemical (PFC) requires a method of oxygenating and removing CO2 from the liquid. Current PFC LAV techniques consist of total liquid ventilation, PFC lavage, and partial liquid ventilation. Because PFC liquid is volatile, it may be lost from the lung or ventilator circuit in the expired gas. ⋯ The results showed that 1) PFC loss rate and exchanger efficiency to remove CO2 increased with increasing gas: PFC liquid flow rates independent of the type of exchanger or PFC liquid; 2) PFC loss rate at any gas or liquid flow rate was greater for the bubbler than for the oxygenator; 3) the oxygenator was more efficient than the bubbler with respect to CO2 elimination; 4) although PFC loss rate increased with temperature and vapor pressure, there was little difference in the EEIs for the temperatures studied. These results 1) identify exchanger requirements necessary to maintain effective CO2 elimination up to four times normal CO2 loading conditions during LAV; 2) suggest that using a membrane oxygenator as the gas exchanger, in concert with stringent fluid temperature control, improves PFC liquid conservation and CO2 elimination relative to bubbler exchanger configurations; 3) highlight the importance of matching the exchanger type to the physiocochemical properties of the specific PFC liquid to optimize CO2 elimination while reducing PFC liquid loss by minimizing gas relative to PFC liquid flow rates. Because PFC liquid loss occurs with all current means of oxygenating and removing CO2, this study raises the importance of developing alternative, bulk-gas-flow-independent, means to recondition PFC liquids.
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Biomed Instrum Technol · Jan 1999
Technological developments and approaches to improving service quality.
In summary, major paradigm shifts in the health care industry are altering the way technology is maintained and supported. Service organizations are now responsible for maintaining a broader base of technology within the health care delivery network and must to this on an extremely rapid, efficient, and productive basis. A number of new technologies are coming on-line, which can allow a health care technology service organization to experience significant improvements in profitability, efficiency, and productivity. ⋯ From there, service organizations should identify the current state-of-the-art service and infrastructure systems and technology. Based on this assessment, a service organization can evaluate best practices and identify new strategies and tactics for improving service delivery. Through better service management control and education of users on the improvement in service, which the new processes and technologies provide, the service organization can realize real, quantifiable improvements in service quality, productivity, and profitability.
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Biomed Instrum Technol · Nov 1998
Treatment of out-of-hospital cardiac arrest with a low-energy impedance-compensating biphasic waveform automatic external defibrillator. The LIFE Investigators.
Few victims of sudden cardiac arrest survive. A new generation of automatic external defibrillators (AEDs), smaller, lighter, easier to use, and less costly, makes the goal of widespread AED deployment and early defibrillation feasible. A low-energy impedance-compensating biphasic waveform allows AED device characteristics more suitable to the goal of early defibrillation than high-energy waveforms. ⋯ At the time of patient transfer, an organized rhythm was present in 65% of the VF patients; asystole was the result in 25%, and VF was in progress in 10%. It is concluded that low-energy impedance-compensating biphasic waveforms terminate long-duration VF at high rates in out-of-hospital cardiac arrest and provide defibrillation rates exceeding those previously achieved with high-energy shocks. Use of this waveform allows AED device characteristics consistent with widespread AED deployment and early defibrillation.