Prediction of Successful Ventilator Weaning Using Airway Occlusion Pressure and Hypercapnic Challenge

Montgomery, Anne; Holle, Rolf H.O.; Neagley, Sara R.; Pierson, David J.; Schoene, Robert B.

doi:10.1378/chest.91.4.496

Cited by 98 publications

(26 citation statements)

References 8 publications

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“…1)). Similarly, when respiratory centre reserve was quantified as the ratio of resting P0.1 to P0.1 recorded at the end of the CO 2 rebreathing manoeuvre (modified from the study of MONTGOMERY et al [17]), there was no difference between the hypercapnic and normocapnic patients (0.42¡0.09 and 0.35¡0.05, respectively (p~0.46)). Figure 2 shows recordings with the twitch interpolation technique in a representative hypercapnic and normocapnic patient, with the former exhibiting complete diaphragmatic activation and the latter incomplete activation.…”

Section: Resultsmentioning

confidence: 99%

The voluntary drive to breathe is not decreased in hypercapnic patients with severe COPD

2001

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The voluntary drive to breathe is not decreased in hypercapnic patients with severe COPD. A. Topeli, F. Laghi, M.J. Tobin. #ERS Journals Ltd 2001. ABSTRACT: How do the respiratory centres of patients with chronic obstructive pulmonary disease (COPD) and hypercapnia respond to acute increases in inspiratory load? A depressed respiratory motor output has long been postulated, but studies on this issue have yielded inconsistent results, partly due to limitations of investigative techniques. Many of these limitations can be overcome by the twitch interpolation technique, which is capable of accurately quantifying the degree of diaphragmatic activation, termed the voluntary drive to breathe. The hypothesis that patients with COPD and hypercapnia compensate for an acute increase in mechanical load on the inspiratory muscles with a lower voluntary drive to breathe than is the case with normocapnic patients was tested.Measurements were obtained in 15 patients with COPD, six of whom displayed hypercapnia and nine normocapnia. The maximum degree of diaphragmatic activation, expressed as a voluntary activation index (mean¡SEM), was higher in hypercapnic than in normocapnic patients (98.7¡0.7 versus 94.5¡0.9% (p~0.006)), as was the mean value (94.5¡0.7 versus 88.5¡1.9% (p~0.01)). Within-patient values of the index were also less variable in the hypercapnic patients (coefficients of variation, 3.4¡0.3 versus 6.1¡0.9%, p~0.01). Multiple regression analysis revealed the ratio of dynamic elastance to maximum transdiaphragmatic pressure, an index of inspiratory muscle loading, and pH as the only variables that correlated with maximum voluntary activation index (r 2~0 .69, p~0.02 for each variable). Contrary to the hypothesis, it was concluded that voluntary activation of the diaphragm was greater and less variable in hypercapnic patients than normocapnic patients with severe chronic obstructive pulmonary disease during an acute increase in inspiratory mechanical load. Whether greater diaphragmatic recruitment during episodes of a severe exacerbation of chronic obstructive pulmonary disease provides a survival advantage for hypercapnic patients with chronic obstructive pulmonary disease remains to be determined.

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Section: Resultsmentioning

confidence: 99%

The voluntary drive to breathe is not decreased in hypercapnic patients with severe COPD

2001

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“…The potential clinical interest in evaluating the CO 2 response test in acute cervical SCI patients could be the ability to identify those patients who will require long-term mechanical ventilation, similarly to what occurred in non-traumatic critically-ill patients ready for weaning of mechanical ventilation in whom a reduced CO 2 response was associated with spontaneous breathing failure 20 and prolonged weaning. 4 Thus, these patients may benefit from early tracheostomy.…”

Section: Discussionmentioning

confidence: 99%

Respiratory CO2 response in acute cervical spinal cord injury (CO2 response in spinal cord injury)

et al. 2013

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Study design: Retrospective study. Objectives: The objective of this study was to compare the CO 2 response of acute tetraplegic cervical spinal cord injury (SCI) patients undergoing mechanical ventilation with a control group of critically ill patients ready for weaning of mechanical ventilation and successfully extubated. Setting: This study was conducted at the intensive care unit of a University Hospital in Mallorca, Spain. Methods: CO 2 response was studied in 12 acute tetraplegic cervical SCI patients at the C4 ÀC7 level and 22 control patients. The control group patients were consecutively selected from a database of patients with mechanical ventilation and who were successfully extubated after a CO 2 response test. To increase the CO 2 , we used the method of re-inhalation of expired air, and we evaluated the hypercapnic ventilatory response, the change in minute ventilation induced by the increase of partial pressure of arterial carbon dioxide (PaCO 2 ), which measures the whole respiratory system (metabolic control, neuromuscular or ventilatory apparatus), and the hypercapnic drive response, the change in the airway occlusion pressure at 100 ms induced by the increase in PaCO 2 , which measures the chemosensitivity of the respiratory center. Results: Cervical SCI patients were younger than the control group patients (26±7 and 62±12 years, respectively; Po0.001). Mean values of the hypercapnic ventilatory response in cervical SCI and control groups were 0.52±0.31 and 0.64±0.33 l min À1 per mm Hg (P ¼ 0.40), respectively, and the hypercapnic drive response was 0.24 ± 0.16 and 0.48 ± 0.23 cm H 2 O per mm Hg (P ¼ 0.001), respectively. Conclusion: Acute tetraplegic cervical SCI patients had reduced hypercapnic drive response that may contribute to the difficult weaning, without reduction in hypercapnic ventilatory response.

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“…Similarly, P0.1/PI,max did not separate the FW and SW patients. The predictive value of P0.1 to indicate FW or SW has been questioned by others [26], who were only able to separate FW and SW patients by a difference in hypercapnic augmentation of P0.1. Nevertheless, most studies [22][23][24][25] have demonstrated that neuromuscular output is augmented in ARF and FW patients.…”

Section: Discussionmentioning

confidence: 99%

Breathing pattern during acute respiratory failure and recovery

Rosario

Sassoon²,

Chetty³

et al. 1997

Eur Respir J

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The objective of this study was to compare the breathing pattern of patients who failed to wean from mechanical ventilation to the pattern during acute respiratory failure. We hypothesized that a similar breathing pattern occurs under both conditions. Breathing pattern, mouth occlusion pressure (P0.1) and maximum inspiratory pressure (PI,max) were measured in 15 patients during acute respiratory failure, within 24 h of the institution of mechanical ventilation, and in 49 patients during recovery, when they were ready for discontinuation from mechanical ventilation. The following indices were calculated: rapid shallow breathing index (respiratory frequency/tidal volume (f R/VT)); rapid shallow breathing-occlusion pressure index (ROP = P0.1·fR/VT); P0.1/PI,max; and effective inspiratory impedance (P0.1/VT/(inspiratory time (t I)).Patients who failed to wean (n=11) had a similar ROP, fR/VT and P0.1/PI,max to those with acute respiratory failure despite a significantly reduced P0.1/VT/t I, the value of which was comparable to that of patients who weaned successfully (n=38). The PI,max of patients who failed to wean was similar to that of patients who weaned successfully.We conclude that patients who failed to wean had a breathing pattern similar to that during acute respiratory failure, despite a reduced mechanical load on the respiratory muscles and a relatively adequate inspiratory muscle strength. This suggests that strategies that enhance respiratory muscle endurance may facilitate weaning.

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Prediction of Successful Ventilator Weaning Using Airway Occlusion Pressure and Hypercapnic Challenge

Cited by 98 publications

References 8 publications

The voluntary drive to breathe is not decreased in hypercapnic patients with severe COPD

The voluntary drive to breathe is not decreased in hypercapnic patients with severe COPD

Respiratory CO2 response in acute cervical spinal cord injury (CO2 response in spinal cord injury)

Breathing pattern during acute respiratory failure and recovery

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