Articles: apnea-diagnosis.
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Journal of neurosurgery · Jun 1992
Apnea testing for the determination of brain death: a modified protocol. Technical note.
The absence of spontaneous respirations at a PaCO2 of 60 mm Hg or above has traditionally been accepted as the respiratory criteria for the determination of brain death. The testing of patients for the presence or absence of apnea has been complicated because the rate of PaCO2 elevation may vary substantially from patient to patient, and a nonlinear relationship exists between the rate of PaCO2 increase and the duration of apnea. In an attempt to refine the apnea test and to further elucidate the physiology of hypercapnia in humans, 11 patients who met all but the respiratory criteria for brain death were evaluated using a modification of a previously utilized apnea testing protocol. ⋯ The mean rate of PaCO2 increase was 5.1 +/- 1.4 mm Hg/min in Group I and 6.7 +/- 3.1 mm Hg/min in Group II. No problems with cardiovascular instability or hypoxia were encountered during testing in this series. This refinement of the apnea test allows for a streamlined and safe approach to brain death detection.
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Intensive care medicine · Jan 1992
Case ReportsBrain death: timing of apnea testing in primary brain stem lesion.
In a 73-year-old patient complete areflexia of the cerebral and peripheral nerves following the rupture of an aneurysm of the basilar artery was diagnosed. During apnea testing the spectral analysis of electroencephalography (EEG) revealed an irreversible shift of peak from 6 to 3 Hz within the low-frequency bands. These findings suggest that apnea testing in patients with primary lesion of the brain stem should be carried out only after an isoelectric EEG.
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Changes in PaCO2, PaO2 and arterial pH were monitored during a 10 min apnoea test in nine clinically brain dead subjects. The patients were preoxygenated for 15 min with 100% O2. During the apnoea test they were oxygenated by tracheal cannulation with 5 l O2 per min. ⋯ With one exception, all of the patients were sufficient oxygenated during the apnoea test. If patients are ventilated to a PaCO2 greater than or equal to 5.5 kPa then 5 min of apnoea testing will increase PaCO2 above 8 kPa. As a few patients may develop hypoxemia, patients should be monitored with pulseoximetry.
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Pediatric pulmonology · Jan 1990
Prospective pneumogram recordings in preterm infants with and without clinical apnea and bradycardia.
Recordings of breathing movements and heart rate (pneumograms) were obtained prospectively in 89 preterm infants at 0-28 days of age to determine if those who develop apnea and/or bradycardia with cyanosis (Group 1) differ from those who do not (Group 2). The 148 pneumograms were blindly analyzed for periodic breathing, bradycardia, longest apnea, and quiet time. Pneumograms were compared between groups at weekly intervals during the first 4 weeks. ⋯ It is concluded that preterm infants who develop apnea and/or bradycardia with cyanosis have a lower mean birthweight and mean weight at recording at less than or equal to 7 days of age than similar asymptomatic preterm infants. Periodic breathing at less than or equal to 7 days of age is associated with the occurrence of clinical symptoms of apnea and/or bradycardia. Normal pneumogram values for groups of 6-21 asymptomatic preterm infants are provided for the first 4 weeks of life.