Trials Comparing Alternative Weaning Modes and Discontinuation Assessments

doi:10.1378/chest.120.6_suppl.425S

Chest

Volume 120, Issue 6, Supplement, December 2001, Pages 425S-437S

https://doi.org/10.1378/chest.120.6_suppl.425S Get rights and content

We identified 16 randomized controlled trials (RCTs) of methods for weaning patients from mechanical ventilation, 8 of which were trials of discontinuation assessment strategies, 5 of which were trials of stepwise reduction in mechanical ventilatory support, and 3 of which were trials comparing alternative ventilation modes for weaning periods lasting < 48 h. We found that different thresholds for deciding when a patient is ready for a trial of spontaneous breathing, different criteria for a successful trial, and different thresholds for extubation may overwhelm the impact of alternative ventilation strategies. Nevertheless, the results of these studies suggest the possibility that multiple daily T-piece weaning or pressure support may be superior to synchronized intermittent mandatory ventilation. Other RCTs suggest that early extubation with the back-up institution of noninvasive positive-pressure ventilation as needed may be a useful strategy in selected patients.

Section snippets

Eligibility Criteria

Our methodology is reported in detail elsewhere in this supplement. For the reviews in this section, we focused on strategies that were designed to facilitate weaning and extubation that involved alternative regimens of assessing suitability for weaning or extubation or alternative strategies for ventilating patients during the weaning process. We excluded studies that reported exclusively physiologic outcomes. We included randomized trials and observational studies that included a control

Results

We identified 16 randomized trials, 15 through MEDLINE and 1 through Excerpta Medica Database.¹⁵¹⁶¹⁷¹⁸¹⁹²⁰²¹²²²³²⁴²⁵²⁶²⁷²⁸²⁹³⁰ One set of trials deals with the decision about what mode of ventilation to use to test the patient's ability to tolerate unassisted breathing. Of the 16 randomized trials, 8 trials¹⁵¹⁶¹⁷¹⁸¹⁹²⁰²¹²² dealt with this choice. We refer to this group of studies as “studies comparing alternative discontinuation assessment strategies.”

In the second clinical context that we

Discussion

These trials have made important observations that are relevant to the care of patients receiving mechanical ventilation, and they represent one of the most well-studied fields in critical-care medicine. We begin with an observation that is applicable to all trials of alternative ventilation modes. A major outcome of these studies of modes of weaning is weaning failure and, in particular, the need for reintubation. While the need for reintubation is important, it is prior to reintubation that

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Successful extubation conventionally necessitates the passing of spontaneous breathing trials (SBTs) and ventilator weaning parameters. We report successful extubation of patients with neuromuscular disease (NMD) and weakness who could not pass them.
NMD-specific extubation criteria and a new extubation protocol were developed. Data were collected on 157 consecutive “unweanable” patients, including 83 transferred from other hospitals who refused tracheostomies. They could not pass the SBTs before or after extubation. Once the pulse oxyhemoglobin saturation (Spo₂) was maintained at ≥ 95% in ambient air, patients were extubated to full noninvasive mechanical ventilation (NIV) support and aggressive mechanically assisted coughing (MAC). Rather than oxygen, NIV and MAC were used to maintain or return the Spo₂ to ≥ 95%. Extubation success was defined as not requiring reintubation during the hospitalization and was considered as a function of diagnosis, preintubation NIV experience, and vital capacity and assisted cough peak flows (CPF) at extubation.
Before hospitalization 96 (61%) patients had no experience with NIV, 41 (26%) used it < 24 h per day, and 20 (13%) were continuously NIV dependent. The first-attempt protocol extubation success rate was 95% (149 patients). All 98 extubation attempts on patients with assisted CPF ≥ 160 L/m were successful. The dependence on continuous NIV and the duration of dependence prior to intubation correlated with extubation success (P < .005). Six of eight patients who initially failed extubation succeeded on subsequent attempts, so only two with no measurable assisted CPF underwent tracheotomy.
Continuous volume-cycled NIV via oral interfaces and masks and MAC with oximetry feedback in ambient air can permit safe extubation of unweanable patients with NMD.
Mechanical ventilation in the cardiac care unit
2010, Cardiac Intensive Care: Expert Consult
Mechanical Ventilation in the Cardiac Care Unit
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Liberation from Mechanical Ventilation: What Monitoring Matters?
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Citation Excerpt :
We specifically use the verb “clarify” versus “answer” definitively because, considered pathophysiologically, no single threshold is likely to demarcate perfectly success and failure in every patient. Nearly all studies and reviews published to date have suggested patients should be “hemodynamically stable” before weaning [4–6,9]. Accordingly, measures of hemodynamic stability including blood pressure and absence of cardiac ischemia have been those most often cited as prerequisites for studies and clinical guidelines.
Over the past 2 decades, the art of “weaning” from mechanical ventilation has been informed by increasing published basic science and outcomes studies. Although monitoring technologies can provide vast amounts of information before, during, and after liberation from mechanical ventilation, little data exists on how to maximally harness even routinely monitored, basic physiologic parameters. Overdependence on technology and derived variables, without data to demonstrate benefit, may even inhibit the patient's progress if it is used inappropriately. We review the scientific evidence for best using routinely available physiologic data and a few more sophisticated and invasive monitoring technologies during weaning. We also suggest future study designs that would better inform the process of liberation from the ventilator and endotracheal extubation.
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Therapist-driven protocols have been shown to decrease the duration of mechanical ventilation, reduce cost, length of stay, and improve the rate of weaning when compared with physician-directed weaning. This article describes protocols used at the author's institution. It describes how the respiratory therapy service interacts with other services within the hospital to provide the optimal outcome for the patient.
Implementation of a weaning algorithm in postoperative cardiac ICU: simple enough to be implemented in a ventilator software<sup>{star, open}</sup>{star, open}La version complète de l'article est disponible sur ScienceDirect<sup>®</sup>, www.sciencedirect.com, doi: 10.1016/j.annfar.2007.02.002.
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Citation Excerpt :
Our study is in line with fast-tracking strategy, implemented in most cardiosurgical ICUs. This strategy favours short-acting anaesthetic agents like remifentanil and weaning protocols aiming at reducing the duration of mechanical ventilation [9,10]. However, remifentanil may trigger hyperalgesia [11] and therefore many groups, like ours, still use long-acting sufentanil.
The aim of this study was to test the efficacy of a respiratory weaning algorithm (WA) in postoperative cardiac surgery patients. This algorithm was made simple enough to be implemented in medium-end ventilator software.
Twenty consecutive postoperative patients who underwent scheduled cardiac surgery with normal postoperative haemodynamic and respiratory status.
A 3 step WA (Controlled Mode Ventilation, Pressure Support (PS) at +20 cmH₂O and at +10 cmH₂O) was applied every 15 minute by the same investigator. A 15 minute period of respiratory stability at one step led to commute to a step ahead until patient was judged “ready for extubation” (RFE, i.e. stable during 15 min under PS +10 cmH₂O). Once reaching this time, the patient was left under PS +10 until nurse and doctors in charge decided extubation according to our routine clinical criteria.
the patients were routinely extubated, in average 187 ± 169 min later than when judged RFE by the algorithm. Heart rate (P < 0.05) and mean arterial pressure rose when they reached the time of effective extubation, by comparison to the RFE time point.
A WA has clinical advantage in cardiac surgery as it reduces respiratory weaning duration. It helps to avoiding haemodynamic stress related to delayed extubation. Such an algorithm is simple enough to be implemented in medium-end ventilators.
Tester l'efficacité d'un algorithme de sevrage ventilatoire (AS) en période postopératoire immédiate de chirurgie cardiaque. Cet algorithme a été conçu pour être suffisamment simple afin de pouvoir être implémenté dans un respirateur de moyen de gamme.
Prospective, en réanimation.
Vingt patients consécutifs opérés de chirurgie cardiaque réglée et ayant des suites postopératoires immédiates simples, sans anomalie hémodynamique ou respiratoire.
Un AS en trois étapes (ventilation contrôlée, aide inspiratoire (PS) à +20 cmH₂O et à +10 cmH₂O) était appliqué toutes les 15 minutes par le même investigateur. Après 15 minutes de stabilité respiratoire sur un mode, le patient était passé au mode suivant jusqu'à ce qu'il soit jugé « prêt pour l'extubation », c'est-à-dire stable durant 15 minutes à PS +10. Le patient était maintenu dans ce mode jusqu'à l'extubation effective, appréciée par l'infirmière et confirmée par le médecin, selon des critères cliniques usuels.
Les patients étaient extubés en moyenne 187 ± 169 minutes après le moment où ils étaient jugés extubables par l'algorithme. La fréquence cardiaque (p < 0,05) et la pression VO₂ augmentaient au moment où le patient était jugé extubables par l'infirmière par comparaison à moment où l'algorithme les avait au préalable jugés extubables.
Cet algorithme présente l'avantage de permettre de reconnaître le moment où le patient serait extubable, de façon plus précoce qu'en situation de routine clinique. Une gestion du sevrage par un algorithme est susceptible de réduire la durée de ventilation et ainsi, la contrainte hémodynamique préextubation. Cet algorithme simple est susceptible d'être inclus dans le logiciel d'un respirateur de moyen de gamme.

View all citing articles on Scopus

: This article is based on work performed by the McMaster University Evidence-based Practice Center, under contract to the Agency for Healthcare Research and Quality (Contract No. 290-97-0017), Rockville, MD.

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Chest

Trials Comparing Alternative Weaning Modes and Discontinuation Assessments

Section snippets

Eligibility Criteria

Results

Discussion

Lancet

Thorac Cardiovasc Surg

Am J Med

Ann Thorac Surg

Lancet

Chest

Chest

Chest

Weaning from mechanical ventilation

Am Rev Respir Dis

Patterns of breathing during successful and unsuccessful trials of weaning from mechanical ventilation

Am Rev Respir Dis

Empirical evidence of bias: dimensions of methodological quality associated with estimates of treatment effects in controlled trials

JAMA

Predictors of weaning from mechanical ventilation [abstract]

Heart Lung

Weaning and outcome from mechanical ventilation

Monaldi Arch Chest Dis

Elevated static compliance of the total respiratory system: early predictor of weaning unsuccess in severed COPD patients mechanically ventilated

Intensive Care Med

Multidimensional predictors of success or failure with early weaning from mechanical ventilation after cardiac surgery

Nurs Res

Survival and prediction of successful ventilator weaning in COPD patients requiring mechanical ventilation for more than 21 days

Eur Respir J

Pulmonary effects of methylprednisolone in patients undergoing coronary artery bypass grafting and early tracheal extubation

Anesth Analg