Voluntary Is Better Than Involuntary Cough Peak Flow for Predicting Re-Intubation After Scheduled Extubation in Cooperative Subjects

Abstract

BACKGROUND:In this study, we compared the predictive accuracy of voluntary cough peak flow (V-CPF) and involuntary cough peak flow (IV-CPF) for re-intubation in mechanically ventilated subjects. METHODS: Endotracheally intubated patients who passed a spontaneous breathing trial and assessment of readiness for extubation were enrolled. Before extubation, V-CPF and IV-CPF were measured. Re-intubation was recorded at 72 h after extubation. RESULTS: A total of 115 extubations in 106 cooperative subjects (including 9 subjects with second extubation) and 5 extubations in 5 uncooperative subjects were recorded. At 72 h, 20 (17.4%) and 1 (25%) instances of re-intubation occurred in cooperative and uncooperative subjects, respectively. In cooperative subjects, those who had been successfully extubated had higher V-CPF than re-intubated subjects

Predicting Extubation Outcome by Cough Peak Flow Measured Using a Built-in Ventilator Flow Meter

“…Another interesting point to note is that V T before cough has been previously reported with a comparable result: The higher the tidal volume, the greater the probability of extubation success. 10 Nevertheless, this feature was never combined with other criteria to predict extubation outcome as it was herein in the composite cough strength score, which was found to be more significantly correlated with early extubation success. It is also important to note that this measure is easily performed at the bedside and is also associated with long-term clinical outcomes (overall extubation success and hospital mortality).…”

“…8,10 This objectively assessed threshold has been retained in a review 25 and was then used to select subjects for further interventional studies. 20 The present study confirms pre- vious results regarding the accuracy of CPF assessment and may lead to an increased use in routine care.…”

“…21 However, objective assessment has been called for 13,22 because some publications assessing the clinical consequences of extubation failure were usually limited by the absence of objective assessment of cough strength. 4 Furthermore, when objective assessments were employed, a variety of measurement conditions were used (spontaneous and voluntary cough 15 ; spontaneous but involuntary cough 10 ; manually assisted cough 12 ; and inclusion or not of neurosurgical subjects with oral endotracheal tubes or tracheostomy 23,24 with possible severe cognitive impairments preventing an adequate response to cough instruction). This has also led to a wide range of cut-off values (Ϫ80 L/min was most adapted for reflex cough in the specific context of neuro-ICU 24 ; Ϫ35 L/min was proposed in a medical ICU 15 ;Ϫ29 L/min was proposed for decannulation 23 ).…”

“…The experimental design is described in Figure 1A CoughAssist device (Philips Respironics, Murrysville, Pennsylvania) was used to inflate a pneumatic lung model (TTL 5601 i, Michigan Instruments, Grand Rapids, Michigan) over a range of nominal pressures (10,20,30,40, and 50 cm H 2 O). Lung model compliance was set to 30 mL/cm H 2 O, and airway resistance was set to 5 cm H 2 O/L/s.…”

“…8 Cough strength can, for example, be evaluated by cough peak flow (CPF). A CPF cut-off value of Ϫ60 L/min for voluntary and unassisted cough in a medical ICU population has found some consensus, [8][9][10][11] but its accuracy is questionable because the pre-cough biomechanical thoracic features are not taken into account. Furthermore, the specificity of CPF assessment for extubation prediction is not known, because one study that reported the prognostic value of CPF did not use a standardized SBT, 12 and therefore it was not possible here to delineate the prediction of successful weaning from mechanical ventilation rather than cough per se (because the glottis cannot be entirely closed in the presence of an ETT 13 ).…”