Weaning from mechanical ventilation: concept development

Comparison between a nurse-led weaning protocol and a weaning protocol based on physician's clinical judgment in ICU patients

PURPOSE

The purpose of this study was to compare a nurse-led weaning protocol with a physician-driven weaning protocol in mechanically ventilated (MV) patients.

METHODS

In this quasi-experimental study with a one-group design, a total of 65 ICU patients, requiring MV for more than 72 h, were selected via convenience sampling. In routine practice, the physician's clinical judgment is needed to determine the patient's readiness for liberation from MV. A physician-driven weaning protocol was compared with a nurse-led protocol, using Burn's Weaning Scale (BWS) in three working phases. Descriptive and inferential statistics were measured for data analysis using SPSS version 16.

RESULTS

Based on BWS, the mean MV duration was 111.75±33.46 h in the nurse-led weaning group and 125.12±43.43 h in the physician-driven weaning group. There was a significant difference in terms of MV duration between the two groups (P = 0.000).

CONCLUSION

The present findings showed that nurses' assessment of patient's readiness for weaning from MV (BWS) is a safe approach during the day, which can reduce MV duration more than other typical methods in ICUs.

Protocolized versus non-protocolized weaning for reducing the duration of mechanical ventilation in critically ill adult patients

BACKGROUND

Reducing weaning time is desirable in minimizing potential complications from mechanical ventilation. Standardized weaning protocols are purported to reduce time spent on mechanical ventilation. However, evidence supporting their use in clinical practice is inconsistent.

OBJECTIVES

To assess the effects of protocolized weaning from mechanical ventilation on the total duration of mechanical ventilation for critically ill adults; ascertain differences between protocolized and non-protocolized weaning in terms of mortality, adverse events, quality of life, weaning duration, intensive care unit (ICU) and hospital length of stay (LOS); and explore variation in outcomes by type of ICU, type of protocol and approach to delivering the protocol.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2010), MEDLINE (1950 to 2010), EMBASE (1988 to 2010), CINAHL (1937 to 2010), LILACS (1982 to 2010), ISI Web of Science and ISI Conference Proceedings (1970 to 2010), Cambridge Scientific Abstracts (inception to 2010) and reference lists of articles. We did not apply language restrictions.

SELECTION CRITERIA

We included randomized and quasi-randomized controlled trials of protocolized weaning versus non-protocolized weaning from mechanical ventilation in critically ill adults.

DATA COLLECTION AND ANALYSIS

Three authors independently assessed trial quality and extracted data. A priori subgroup and sensitivity analyses were performed. We contacted study authors for additional information.

MAIN RESULTS

Eleven trials that included 1971 patients met the inclusion criteria. The total duration of mechanical ventilation geometric mean in the protocolized weaning group was on average reduced by 25% compared with the usual care group (N = 10 trials, 95% CI 9% to 39%, P = 0.006); weaning duration was reduced by 78% (N = 6 trials, 95% CI 31% to 93%, P = 0.009); and ICU LOS by 10% (N = 8 trials, 95% CI 2% to 19%, P = 0.02). There was significant heterogeneity among studies for total duration of mechanical ventilation (I(2) = 76%, P < 0.01) and weaning duration (I(2) = 97%, P < 0.01), which could not be explained by subgroup analyses based on type of unit or type of approach.

AUTHORS' CONCLUSIONS

There is some evidence of a reduction in the duration of mechanical ventilation, weaning duration and ICU LOS with use of standardized protocols, but there is significant heterogeneity among studies and an insufficient number of studies to investigate the source of this heterogeneity. Although some study authors suggest that organizational context may influence outcomes, these factors were not considered in all included studies and therefore could not be evaluated.

Issues in weaning from mechanical ventilation: literature review

AIM

The aim of this paper is to raise questions on the effect of skill mix and organizational structure on weaning from mechanical ventilation.

BACKGROUND

Mechanical ventilation is an essential life-saving technology. There are, however, numerous associated complications that influence the morbidity and mortality of patients receiving intensive care. Therefore, it was essential to use the safest and most effective form of ventilation for the shortest possible duration. Because of the potential complications and costs of mechanical ventilation, research to date have focused on accurate weaning readiness assessment, methods and organizational aspects that influence the weaning process.

METHOD

In early 2005, the literature was reviewed from 1986 to 2004 by accessing the following databases: Medline, Proquest, Science Direct, CINAHL, and Blackwell Science. The keywords mechanical ventilation, weaning, protocols, critical care, nursing role, decision-making and weaning readiness were used separately and combinations.

DISCUSSION

Controversy exists in weaning practices about appropriate and efficacious weaning readiness assessment indicators, the best method of weaning and the use of weaning protocols. Arguably, the implementation of weaning protocols may have little effect in an environment that favours collaboration between nursing and medical staff, autonomous nursing decision-making in relation to weaning practices, and high numbers of nurses qualified at postgraduate level.

CONCLUSION

Further research is required that better quantifies critical care nurses' role in weaning practices and the contextual issues that influence both the nursing role and the process of weaning from mechanical ventilation.

Weaning Readiness and Fluid Balance in Older Critically Ill Surgical Patients

• BackgroundFew studies address predictors for successful weaning of older adults from mechanical ventilation.

• ObjectiveTo develop a clinical profile of older patients who are successfully weaned from long-term mechanical ventilation.

• MethodsForty patients in the trauma and surgical intensive care unit who were at least 60 years old were enrolled in the study after 3 days of active weaning and were monitored daily until successfully weaned or until the end of the 14-day study. Hemodynamic and gas exchange variables, fluid balance, oxygen cost of breathing, and scores on the Burns Weaning Assessment Program were analyzed.

• ResultsCompared with patients who were not weaned, successfully weaned patients required mechanical ventilation for 5.3 days, started active weaning earlier (mean 10.7 vs 14.5 days, P = .04), had lower mean negative daily fluid balances in the beginning (−0.394 vs 1.107 L, P = .004), and had lower mean net cumulative fluid balances (6.856 vs 16.212 L) at the time of enrollment. They also maintained both a lower mean net cumulative fluid balance (10.753 vs 25.049 L, P= .02) and a negative daily fluid balance (−0.389 vs 1.904 L, P = .03) throughout. Their mean central venous pressure decreased over time and was significantly lower (P&lt;.001).

• ConclusionPersistent positive fluid balance in older surgical patients is associated with prolonged mechanical ventilation. Estimates of fluid balance might be useful in weaning older patients from long-term mechanical ventilation.

The science of weaning: when and how?

Weaning patients from long-term mechanical ventilation continues to be a goal of clinicians and scientists and the hospitals charged with their care. This article describes the science of the "wean" and the "how" of weaning. A goal of scientists has been to develop predictors that determine accurately the optimal time to initiate weaning. Unfortunately to date none has emerged as superior. Quite simply, predictors do not predict. In contrast, methods that decrease variation in care practices have demonstrated positive outcomes. The methods include protocols for weaning trials and sedation and other system initiatives inclusive of a multidisciplinary plan of care or clinical pathway.

Weaning from ventilation in paediatric intensive care: an intervention study

OBJECTIVE

To standardise the paediatric intensive care unit (PICU) team's approach to weaning paediatric patients from mechanical ventilation.

METHOD

The study employed a time series design over 2 years. A total of 220 patients (pre-intervention n=107 and post-intervention n=113) were studied. Independent variables measured in both the pre- and post-intervention groups included total ventilation time (TVT), weaning duration (WD), and length of stay (LOS), as well as quality indicators (weaning failure and reintubation rates).

RESULTS

The pre-intervention analysis demonstrated an existing fluctuation between outcome variables. When outcome indicators were compared between the pre- and post-intervention groups, both TVT and LOS were longer post-intervention (median difference: TVT -15.8 hours, P<0.068; and LOS -23.75 hours, P<0.088). WD was comparable between groups (median difference: WD -1.5 hours, P<0.427). Quality indicators were better post-intervention. Kaplan-Meier survival analysis demonstrated that long-term ventilated patients post-intervention had a reduced probability of remaining ventilated.

CONCLUSION

Weaning children from mechanical ventilation can be performed safely and effectively with the aid of collaborative guidelines. Although times were prolonged, the quality indicators were slightly improved, indicating that quicker was not always better. Long-term ventilated patients, in particular, would appear to benefit from weaning guidelines.

Can protocolised-weaning developed in the United States transfer to the United Kingdom context: a discussion

Weaning patients from mechanical ventilation using standardised protocols has been demonstrated to be safe and effective in reducing mechanical ventilation time, intensive care unit (ICU) stay and costs. Studies supporting this have all been conducted in the United States of America and weaning protocols are not widely used in the United Kingdom. With such a strong scientific evidence-base for protocolised-weaning, it is unclear why the introduction of evidence-based practice in this area is so low in the UK. There may be a number of reasons for this. First, it may be that the evidence is considered not to apply to different settings, particularly between the USA and UK where there are many differences in health care cultures. Second, it is suggested that the strength of evidence is not the only factor to account for when trying to introduce research evidence into practice [Qual. Health Care 7 (1998) 149]. The context or environment into which the research is to be implemented and how the implementation process is facilitated are equally important factors to be considered. Kitson et al. [Qual. Health Care 7 (1998) 149] argue that the interplay between the three factors of evidence, context and facilitation, enable the successful implementation of evidence-based practice. This discussion paper explores the factors that influence the introduction of weaning protocols. The discussion is structured around the three core elements from Kitson et al.'s conceptual framework and it draws upon examples of UK and USA contextual differences from Northern Ireland (NI) and Virginia (VA).

Subjective Perceptions and Physiological Variables During Weaning From Mechanical Ventilation

• Background As costs related to mechanical ventilation increase, clear indicators of patients’ readiness to be weaned are needed. Research has not yet yielded a consensus on physiological variables that are consistent correlates of weaning outcomes. Subjective perceptions rarely have been examined for their contribution to successful weaning.

• Objective To explore the subjective perceptions of dyspnea, fatigue, and self-efficacy and selected physiological variables in patients being weaned from mechanical ventilation.

• Methods Data were collected prospectively on 68 patients being weaned from mechanical ventilation. Subjective perceptions were measured by using 3 visual analog scales; physiological variables were measured by using the Burns Weaning Assessment Program and a patient profile. Weaning outcomes were recorded 24 hours after data collection.

• Results Participants were primarily white women and required mechanical ventilation for a mean of less than 4 days. Participants reported mild dyspnea, moderate fatigue, and high weaning self-efficacy. High Pao2, low Paco2, stable hemodynamic status, adequate cough and swallow reflexes, no metabolic changes, and no abdominal problems were associated with complete weaning (P = .05). Subjective perceptions were associated with physiological variables but not with weaning outcomes.

• Conclusions Multidimensional assessment of both primary and secondary indicators of readiness to be weaned is necessary for timely, efficient weaning from mechanical ventilation. Primary assessments include physiological variables related to gas exchange, hemodynamic status, diaphragmatic expansion, and airway clearance. Secondary assessments include perceptions related to key physiological variables. Additional research is needed to determine the predictive value of physiological variables and perceptions of dyspnea, fatigue, and self-efficacy.

Improving outcomes for mechanically ventilated medical intensive care unit patients using advanced practice nurses: a 6-year experience

The value of an APN in a role such as for the management of patients requiring LTMV is easily recognized. There are few healthcare providers who are as uniquely qualified to ensure the successful resolution of the many complex clinical and system issues that affect these patients' outcomes. Similar models of care using APNs in similar roles have been used successfully in other populations of patients at our institution. We hope that other hospitals will implement models using the APN to manage and monitor complex patient populations and continue to report the results so that the true value of the APN is recognized.

Weaning Older Patients From Long-term Mechanical Ventilation: A Pilot Study

• Background As older persons in the intensive care unit increasingly require long-term mechanical ventilation, accurate indications of readiness for weaning from ventilatory support are needed to avoid premature extubation.

• Objective To describe temporal changes in pulmonary and systemic variables in older adults receiving long-term mechanical ventilation.

• Methods After 3 days of unsuccessful attempts at weaning from ventilatory support, 10 trauma and surgical patients more than 60 years old were monitored daily. Previously reported predictors of the duration of mechanical ventilation and weaning outcome were measured, including hemodynamic and gas exchange variables, oxygen cost of breathing, and the score on the Burns Weaning Assessment Program.

• Results The 6 patients who could be weaned from ventilatory support were younger (median age, 71.5 years) than the 4 patients who could not be weaned (median age, 80 years). Patients who could be weaned were ready for weaning by day 11 of their stay in the intensive care unit and required an additional 5.5 days of mechanical ventilation; those who could not be weaned were not ready for weaning until day 17. All patients initially had increases in oxygen consumption during weaning; those who were successfully weaned had decreases before extubation. Respiratory rate, maximal inspiratory pressure, the ratio of Pao2 to fraction of inspired oxygen, and mean arterial pressure were higher in patients who could be weaned, and oxygen cost of breathing and central venous pressure were lower.

• Conclusion Further study of weaning in older adults is warranted.

Prolonged mechanical ventilation and tracheostomy in the elderly

Mechanical ventilation is a life-sustaining technology used with increasing frequency in the elderly population. Prolonged mechanical ventilation is associated with high morbidity, mortality, and poor functional status. Care of these complex patients requires a coordinated multidisciplinary approach to optimize outcome. To minimize mortality and morbidity and contain health care costs, it is essential to identify patients at high risk for prolonged ventilation and to implement early interventions to curtail functional decline. In this article, the incidence and outcome of prolonged mechanical ventilation is reviewed, along with interventions to promote recovery. In particular, the role of tracheostomy timing and placement is discussed.

The weaning continuum use of Acute Physiology and Chronic Health Evaluation III, Burns Wean Assessment Program, Therapeutic Intervention Scoring System, and Wean Index scores to establish stages of weaning

OBJECTIVE

To determine whether four stages of weaning (acute, prewean, wean, and outcome) could be identified by using clinical instruments designed to quantify severity of illness, patient stability, or weaning readiness. The instruments used were the Acute Physiology and Chronic Health Evaluation (APACHE III), the Therapeutic Intervention Scoring System (TISS), the Burns Wean Assessment Program (BWAP), and the Wean Index (WI). The stages were adapted from those proposed by the American Association of Critical Care Nurses Third National Study Group's Weaning Continuum Model.

DESIGN

Prospective, convenience cohort. This study was part of a larger study designed to test an outcomes managed approach to weaning by using an outcomes manager and a clinical pathway.

SETTING

University medical intensive care unit.

PATIENTS

Adult patients requiring mechanical ventilation >3 days admitted to the medical intensive care unit between November 1994 and May 1995.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Scores for the APACHE III, TISS, BWAP, and WI were collected on 97 patients every other day until they weaned, were transferred, or died. Outcomes described for each stage of weaning were dated on the clinical pathway when achieved. Comments about patient stability and ventilator progress also were recorded along with a subjective determination of the stage of weaning. We used decision rules to identify time intervals for each stage of weaning and outcomes attained by stage. Finally, APACHE III, TISS, BWAP, and WI scores were placed in each stage by date for analysis. The APACHE III, TISS, and BWAP scores were able to differentiate the acute, prewean, and wean stages but not the outcome stage.

CONCLUSIONS

By identifying distinct scores for each stage, we may be able to better explore appropriate interventions for the stages as well as predict weaning outcomes. Indices that include physiologic and respiratory factors can differentiate weaning stages, but respiratory factors alone cannot.

Research methodology issues related to interviewing the mechanically ventilated patient

Difficulties conducting research in vulnerable or frail patient populations limit the data-based information on which to base practice in these populations. Although there are many challenges in this type of research, they are not insurmountable, and, in an effort to encourage others interested in studying vulnerable patient populations, we discuss the methodological process used to prospectively study one vulnerable group. Interviews about perceptions of weaning, fatigue, mood, and sleep/rest states were conducted with 20 patients who were chronically critically ill and required long-term mechanical ventilation. Illness severity and communication difficulties were primary considerations in the design, development, and implementation of the study. Ethical considerations, informed consent, sample representation, and data collection issues are discussed.