Capabilities of a mobile extracorporeal membrane oxygenation service for severe respiratory failure delivered by intensive care specialists.

We conducted a single-centre observational study of retrievals for severe respiratory failure over 12 months. Our intensivist-delivered retrieval service has mobile extracorporeal membrane oxygenation capabilities. Sixty patients were analysed: 34 (57%) were female and the mean (SD) age was 44.1 (13.6) years. The mean (SD) PaO2 /FI O2 ratio at referral was 10.2 (4.1) kPa and median (IQR [range]) Murray score was 3.25 (3.0-3.5 [1.5-4.0]). Forty-eight patients (80%) required veno-venous extracorporeal membrane oxygenation at the referring centre. There were no cannulation or extracorporeal membrane oxygenation-related complications. The median (IQR [range]) retrieval distance was 47.2 (14.9-77.0 [2.3-342.0]) miles. There were no major adverse events during retrieval. Thirty-seven patients (77%) who received extracorporeal membrane oxygenation survived to discharge from the intensive care unit and 36 patients (75%) were alive after six months. Senior intensivist-initiated and delivered mobile extracorporeal membrane oxygenation is safe and associated with a high incidence of survival.

Isoflurane and coronary heart disease.

Early studies indicated that isoflurane caused coronary steal and should therefore be avoided in patients with coronary heart disease. Subsequently, more detailed trials have disputed this and have shown that as long as coronary perfusion pressure is maintained, isoflurane does not cause coronary steal or myocardial ischaemia. There is now growing evidence, initially in animal work but more recently in human studies, that isoflurane has myocardial protective properties, limiting infarct size and improving functional recovery from myocardial ischaemia. The mechanism for this protection mimics ischaemic preconditioning and involves the opening of adenosine triphosphate-dependent potassium channels. The few studies comparing the myocardial protection offered by individual anaesthetic agents indicate that isoflurane represents the anaesthetic agent of choice for patients with coronary heart disease.

A comparison of inter-aural attenuation with the Etymotic ER-3A insert earphone and the Telephonics TDH-39 supra-aural earphone.

One of the many reported advantages of the insert earphone over the supra-aural earphone is increased inter-aural attenuation (IA). Minimum values of IA determine the need for masking of the non-test ear in air-conduction audiometry. The aim of the present study was to measure inter-aural attenuation for the Etymotic Research ER-3A insert earphone (with deep and shallow insertion of the ear plug within the ear canal) and compare this with the supra-aural Telephonics TDH-39/MX41-AR earphone/cushion combination. Subjects were 18 adults ranging in age from 38 to 68 years (mean 50 years). Each subject had no hearing in one ear following translabyrinthine surgery for removal of an acoustic neuroma. The opposite ear had hearing thresholds better than 40 dB HL and an air-bone gap of less than 10 dB at any audiometric frequency. Pure tone air-conduction thresholds were obtained in the range 0.25-8 kHz. Deep insertion of the insert earphone was deemed to occur when the outside edge of the ear plug was flush with the entrance of the ear canal. Shallow insertion was deemed to occur when half of the ear plug (6 mm) was inside the entrance of the ear canal. IA was defined operationally as the difference between the good-ear and poor-ear not-masked air conduction threshold for a given audiometric frequency and earphone. The results show that the TDH-39/MX41-AR combination provides a median IA of approximately 60 dB with a lower limit of approximately 45 dB. Greater IA was obtained with the ER-3A insert earphone but this depended on the depth of insertion. With a deep insertion, the 1A values were some 15-20 dB greater than with the supra-aural earphone. Although frequency-specific IA values are provided, a simple rule of thumb is to apply masking to the non-test ear when the pure tone airconduction signal from the ER-3A insert earphone exceeds the bone conduction threshold of the non-test ear by 55 dB HL or more. If it is not possible to obtain a deep insertion depth this value should be reduced by 5 dB.

From skyhooks to walking sticks: on the road to nonrational decision making.

The amount of information that should be processed to reach a rational solution is so vast that it overwhelms our limited memory and analytic capacity. To grapple at all with real problems, we must shrink them to mind size. As Nobel Laureate Herbert Simon has suggested, we must learn to "satisfice." Using examples and a case history of managerial succession, Agnew and Brown demonstrate the importance of nonrational factors in decision making. "Skyhooks," their first major concept, are composed of an individual's strong beliefs and biases that appear almost as acts of faith without any obvious foundation. They help the exceptional executive operate on a limited set of alternatives. But while skyhooks give direction, they do not provide the means to reach a destination. Simpler conceptual models, or "walking sticks," are necessary to cover the rocky trails. Agnew and Brown offer four walking sticks that can be applied to managerial succession problems. The first walking stick considers executive decision making in three parts--nonrational, semirational, and rational--and covers the conditions in which each component comes into play. The second helps examine human resources as fixed or fluid and as assets or liabilities to develop a schema for manpower accounting in executive succession. Playing vs. talking a good executive game is the topic for walking stick three. The concern here is to distinguish the real players--who can manage systems--from the mere talkers, who can manage only fragments of systems. The fourth walking stick draws on the law of resource gravitation and crystallization, a law with implications for trainers: You can't fashion management training to fit all comers; instead, you must tailor it to what the trainees already are and know.