Physiological comparison of three spontaneous breathing trials in difficult-to-wean patients

Servei de Medicina Intensiva, Hospital Santa Creu i Sant Pau, C. Sant Quintí 89, 08041, Barcelona, Spain.
Intensive Care Medicine (Impact Factor: 7.21). 03/2010; 36(7):1171-9. DOI: 10.1007/s00134-010-1870-0
Source: PubMed


To compare cardiovascular and respiratory responses to different spontaneous breathing trials (SBT) in difficult-to-wean patients using T-piece and pressure support ventilation (PSV) with or without positive end-expiratory pressure (PEEP).
Prospective physiological study. Fourteen patients who were monitored with a Swan-Ganz catheter and had failed a previous T-piece trial were studied. Three SBTs were performed in random order in all patients: PSV with PEEP (PSV-PEEP), PSV without PEEP (PSV-ZEEP), and T-piece. PSV level was 7 cmH(2)O, and PEEP was 5 cmH(2)O. Inspiratory muscle effort was calculated, and hemodynamic parameters were measured using standard methods. RESULTS [MEDIAN (AND INTERQUARTILE RANGE)]: Most patients succeeded in the PSV-PEEP (11/14) and PSV-ZEEP (8/14) trials, but all failed the T-piece trial. Patient effort was significantly higher during T-piece than during PSV with or without PEEP [esophageal pressure-time product was 292 (238-512), 128 (58-299), and 148 (100-465) cmH(2)O x s/min, respectively, p < 0.05]. Left ventricular heart failure was observed in 11 of the 14 patients during the T-piece trial. Pulmonary artery occlusion pressure and respiratory rate were significantly higher during T-piece than with PSV-PEEP [21 (18-24) mmHg versus 17 (14-22) mmHg, p < 0.05 and 27 (21-35) breaths/min versus 19 (16-29) breaths/min, p < 0.05 respectively]. Tidal volume was significantly lower during the T-piece trial.
In this selected population of difficult-to-wean patients, PSV and PSV plus PEEP markedly modified the breathing pattern, inspiratory muscle effort, and cardiovascular response as compared to the T-piece. Caregivers should be aware of these differences in SBT as they may play an important role in weaning decision-making.

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    • "Several reversible causes such as respiratory and/or cardiac load, neuromuscular, and metabolic and endocrine disorders have been attributed as causes of difficult weaning. Besides cardiovascular-related causes [4], neuromuscular weaknesses is also a common cause of failure to wean from the ventilator; the causes include polyneuropathy and myopathy [5]. Rarely, undiagnosed, advanced cervical spondylotic myelopathy and syringomyelia may cause acute respiratory failure and subsequent failure to extubate [6]. "
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    American Journal of Case Reports 04/2014; 15:163-167. DOI:10.12659/AJCR.890284
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    • "During the SBT, we assessed the patients by using a standard protocol [18]. The patient was thereby completely disconnected from the ventilator to see inspiratory muscle activity during the whole inspiratory period and to avoid effects of triggering pressure support by only brief diaphragmatic contractions [24]. Conventional criteria were used to decide when to terminate the SBT. "
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    Critical care (London, England) 08/2013; 17(4):R182. DOI:10.1186/cc12865 · 4.48 Impact Factor
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    • "Although there was a significant difference in alveolar ventilation among CG and PSVG, both groups were mostly within the normal range of CO 2 (except one time in the CG) and both weaning protocols may be considered. It is likely that the pressure provided by PSV may have produced an appropriate V T , commonly not accomplished by horses at the return of spontaneous ventilation (Brochard et al. 1987; Esteban et al. 1994; Patroniti et al. 2004; Ezingeard et al. 2006; Cabello et al. 2010). This is supported by the low V T observed in horses at the first spontaneous breath (CG 3.15 AE 1.27 L and PSVG 3.02 AE 1.85 L) and by Table 2 Cardiovascular and metabolic parameters of horses from CG and PSVG (mean AE SD) "
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    Veterinary Anaesthesia and Analgesia 04/2013; 40(4). DOI:10.1111/vaa.12041 · 1.72 Impact Factor
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