Weaning

To determine how protocol-based weaning compared with usual physician-directed weaning for discontinuation of positive-pressure ventilation, Krishnan and colleagues used a prospective, controlled design to study 145 patients randomized to the usual care group and 154 patients assigned to the protocol group in a closed medical intensive care unit (ICU) with a high physician-staffing level and structured, system-based rounds. The results showed no difference in the success of discontinuing mechanical ventilation (74.7 vs. 75.2%, p = 0.92), the duration of mechanical ventilation (61 vs. 68 hours, p = 0.61), or hospital mortality (36 vs. 33%). Thus, a protocol-directed weaning may not be necessary in a closed ICU with generous physician staffing and structured rounds. However, the authors did note that the results of these studies may not apply to all ICU settings.

Laghi and coworker asked, "Do patients who fail a trial of weaning from mechanical ventilation develop diaphragmatic fatigue?". Transdiaphragmatic pressure was recorded during twitch stimulation of the phrenic nerves before and 30 minutes after completing a spontaneous breathing trial (lasting up to 60 minutes) in 11 weaning-failure and 8 weaning-success patients. Twitch transdiaphragmatic pressure was 8.9 cm H₂O before the trials and 9.4 cm H₂O after the trials in the weaning-failure patients; the corresponding values in the weaning-success patients were 10.3 and 11.2 cm H₂O. The failure of twitch pressure to decrease in the weaning-failure patients appears to have arisen because physicians interrupted the trial based on clinical manifestations of respiratory distress before patients had sufficient time to develop contractile fatigue. Weaning-failure patients displayed increased recruitment of rib cage and expiratory muscles, and considerable diaphragmatic weakness. The authors conclude that patients failing a trial of weaning from mechanical ventilation do not develop low-frequency fatigue of the diaphragm, although many patients display severe diaphragmatic weakness.

Ferrer and coworkers randomized 43 patients who failed trials of spontaneous breathing on three consecutive days to extubation plus noninvasive ventilation or to continued intubation plus daily spontaneous breathing trials. The trial was stopped early because the end-point was reached after studying half the planned study population. Compared with conventional weaning, patients weaned with noninvasive ventilation had a shorter duration of invasive ventilation (9.5 versus 20.1 days), shorter stay in ICU (14.1 versus 25.0 days), shorter hospital stay (27.8 versus 40.8 days), less need for tracheotomy (1.5 versus 13.6%), lower incidence of nosocomial pneumonia (5.2 versus 13.6%), lower incidence of septic shock (2.1 versus 9.4%), greater ICU survival (19.9 versus 13.6%), and greater 90-day survival (about 75% versus 40%). Conventional weaning was independently associated with decreased ICU survival (odds ratio, 6.6) and decreased 90-day survival (odds ratio, 3.5). The authors conclude that use of noninvasive ventilation in patients who fail three consecutive days of conventional weaning results in shorter duration of mechanical ventilation, fewer complication, less need for tracheotomy, and increased ICU and 90-day survival. An editorial commentary by Navalesi and coworkers accompanies this article.

Citations 1-4 of 4 total displayed.

A Prospective, Controlled Trial of a Protocol-based Strategy to Discontinue Mechanical Ventilation

Jerry A. Krishnan, Dana Moore, Carey Robeson, Cynthia S. Rand, and Henry E. Fessler
Am. J. Respir. Crit. Care Med. 169: 673 -678. First published online as doi:10.1164/rccm.200306-761OC [Abstract] [Full text]

Weaning and Noninvasive Ventilation: The Odd Couple

Paolo Navalesi
Am. J. Respir. Crit. Care Med. 168: 5-6. [Full text]

Noninvasive Ventilation during Persistent Weaning Failure: A Randomized Controlled Trial

Miquel Ferrer, Antonio Esquinas, Francisco Arancibia, Torsten Thomas Bauer, Gumersindo Gonzalez, Andres Carrillo, Robert Rodriguez-Roisin, and Antoni Torres
Am. J. Respir. Crit. Care Med. 168: 70 -76. First published online as doi:10.1164/rccm.200209-1074OC [Abstract] [Full text]

Is Weaning Failure Caused by Low-Frequency Fatigue of the Diaphragm?

Franco Laghi, Steven E. Cattapan, Amal Jubran, Sairam Parthasarathy, Paul Warshawsky, Yoon-Sub A. Choi, and Martin J. Tobin
Am. J. Respir. Crit. Care Med. 167: 120 -127. First published online as doi:10.1164/rccm.200210-1246OC [Abstract] [Full text]

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