Hypercapnia test as a predictor of success in spontaneous breathing trials and extubation.
Respir Care
; 53(8): 1012-8, 2008 Aug.
Article
em En
| MEDLINE
| ID: mdl-18655738
ABSTRACT
BACKGROUND:
The ventilatory capacity of the respiratory neuromuscular system can be studied with the hypercapnia test.OBJECTIVE:
To determine whether decreased response to the hypercapnia test is associated with failure to pass a spontaneous breathing trial (SBT) or extubation failure.METHODS:
We studied 103 intubated patients ready for SBT. We used a hypercapnia test in which we approximately doubled the dead space and thus caused re-inhalation of expired air. We calculated 3 ratios the ratio of P(0.1) (airway occlusion pressure 0.1 s after the onset of inspiratory effort) during hypercapnia test to baseline P(0.1); the ratio of the change in minute volume [DeltaV(E)] to the change in P(aCO(2)) (we call this ratio the hypercapnic ventilatory response); and the ratio of the change in P(0.1) [DeltaP(0.1)] to the change P(aCO(2)) (we call this ratio the hypercapnic-respiratory-drive response).RESULTS:
Thirty-six patients failed the SBT, and 11 patients failed extubation. The mean values for the SBT/extubation-success group, the extubation-failure group, and the SBT-failure group, respectively, were ratio of hypercapnia-test P(0.1) to baseline P(0.1) 4.3 +/- 2.7, 3.7 +/- 1.3, and 3.0 +/- 1.8 (P = .03); hypercapnic ventilatory response 0.60 +/- 0.35 L/min/mm Hg, 0.50 +/- 0.26 L/min/mm Hg, and 0.31 +/- 0.21 L/min/mm Hg (P < .001); hypercapnic respiratory-drive response 0.48 +/- 0.24 cm H(2)O/mm Hg, 0.42 +/- 0.19 cm H(2)O/mm Hg, and 0.27 +/- 0.15 cm H(2)O/mm Hg (P < .001). For predicting SBT/extubation success, the sensitivities and specificities, respectively, were ratio of hypercapnia-test P(0.1) to baseline P(0.1) 0.80 and 0.47; hypercapnic ventilatory response 0.86 and 0.53; hypercapnic respiratory-drive response 0.82 and 0.55.CONCLUSIONS:
The SBT/extubation-failure patients had less response to the hypercapnia test than did the SBT/extubation-success patients, and the hypercapnia test was not useful in predicting SBT or extubation success.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Insuficiência Respiratória
/
Desmame do Respirador
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Hipercapnia
Tipo de estudo:
Clinical_trials
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Etiology_studies
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Prognostic_studies
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Risk_factors_studies
Limite:
Aged
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Ano de publicação:
2008
Tipo de documento:
Article