SESSION TITLE: Diagnostic Procedures and Interventions Posters
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 29, 2014 at 01:30 PM - 02:30 PM
PURPOSE: Apnea testing may demonstrate loss of ventilatory brain stem function; however it can cause hypotension, hypoxia and cardiac arrhythmias. These complications create barriers for the completion of the test, leading to additional confirmatory studies being performed, such as cerebral angiography or nuclear imaging. End-tidal carbon dioxide level (EtCO2) has been frequently documented as a surrogate for partial pressure of carbon dioxide (PaCO2). Additionally, lung sliding is known to detect pleural moving during ventilation. We investigated if continuous lung sliding, in conjunction with comparing pre- and post-apnea test EtCO2, is effective as a strategy to detect lack of ventilation during an apnea test.
METHODS: A patient with anoxic brain injury required evaluation of brainstem function with an apnea test. Prior to the test, patient was pre-oxygenated with 100% FiO2 for 5 minutes, peripheral oxygen saturation was 100%, lung sliding was seen in bilateral lung fields and pre-apnea test EtCO2 was 39mmHg. During the 8 minute apnea test, 1L/min of 100% oxygen was given for passive oxygenation and lung sliding was performed in the same locations as prior to apnea test.
RESULTS: Without ventilator support, we observed disappearance of lung sliding under ultrasound. His post-test EtCO2 was 83mm Hg which made a positive apnea test based on our institutional criteria. When placed back on ventilator lung sliding returned and EtC02 fell to normal range.
CONCLUSIONS: Lung sliding was a surrogate to demonstrate the patient was not ventilating, which was confirmed by pre- and post-apnea test EtCO2.
CLINICAL IMPLICATIONS: Most current guidelines on brain stem examination suggest comparing pre- and post-PaCO2 after 8 minutes of apnea. Disappearance of lung sliding can be valuable supplementary information especially for those patients unable to tolerate completion of an 8 minute apnea test secondary to cardiovascular complications.
DISCLOSURE: The following authors have nothing to disclose: Adaira Landry, Young Lee
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