Weaning from mechanical ventilation

Acupuncture for ventilator-dependent patients at a hospital-based respiratory care center: A randomized controlled trial

Background

In intensive care units, mechanical ventilation is an important therapy to help patients with dyspnea. However, long-term ventilator dependence would consume huge medical resources and increase the risk of morbidity and mortality. The aim of the study was to examine the efficacy of the acupuncture combined with western medical care on ventilator parameters in ventilator-dependent patients.

Methods

In this clinical trial, 80 ventilator-dependent patients aged 20 to 80 years old were randomly assigned to acupuncture group and control group in the respiratory care center (RCC) of Changhua Christian Hospital. Besides regular medical care and therapy, participants in the acupuncture group received acupuncture therapy at the same 17 acu-points for 20 minutes once a day, a total of 12 sessions. The ventilator parameters were recorded to evaluate the respiratory efficiency for all participants. The primary outcome was rapid shallow breathing index (RSBI), and secondary outcomes were respiratory rate (RR), tidal volume (TV) and ventilation per minute (MV).

Results

Though there was no significant difference in the parameter between the acupuncture group and the control group, we found the trend of decreasing RSBI in the acupuncture group. In subgroup analyses, the mean of RSBI significantly decreased 16.02 (with the SD in 60.84) in acupuncture group, while it increased 17.84 (with the SD in 39.38) in control group (p=0.036) after 12 sessions.

Conclusion

Acupuncture treatment can improve breathing ability of patients with respirator dependence in respiratory care center.

Variation of Risk Factors for Cause-Specific Reintubation: A Preliminary Study

Unexpected reintubation may occur, even if the risk factors are considered and a spontaneous breathing trial is successful. Reintubation is thought to be caused by various factors. Several studies have investigated the risk factors of reintubation, but most did not classify reintubation by cause. We retrospectively classified patients undergoing reintubation at intensive care unit by cause (respiratory insufficiency vs. nonrespiratory insufficiency) to examine the cause-specific risk factors of reintubation. A total of 262 patients were included; reintubation within 48 hours after extubation was performed in 12 patients (reintubation rate, 4.5%). After classification by cause of reintubation, the pressure of arterial oxygen to fractional inspired oxygen concentration (P/F) ratio exhibited a significant association with reintubation only in the respiratory insufficiency group (odds ratio (OR) 0.989, 95% confidence interval (CI) 0.980 to 0.999, p=0.036, and OR 0.989, 95% CI 0.979 to 0.999, p=0.026, in the univariate and multivariate analyses, respectively). In the propensity score analysis, a P/F ratio ≤ 200 may be a risk factor for reintubation in the respiratory insufficiency group (OR 7.811, 95% CI 1.345 to 45.367, p=0.022). In the nonrespiratory insufficiency group, intubation duration was significantly related to reintubation (OR 1.165, 95% CI 1.012 to 1.342, p=0.033, and OR 1.163, 95% CI 1.004 to 1.348, p=0.044, in the univariate and multivariate analyses, respectively). In conclusion, a low P/F ratio at extubation may be a risk factor for reintubation due to respiratory insufficiency. In the nonrespiratory insufficiency group, intubation duration may be significantly related to reintubation. The risk factors for reintubation may differ by the cause of reintubation. Further large-scale randomized controlled trials are required.

Automated weaning and SBT systems versus non-automated weaning strategies for weaning time in invasively ventilated critically ill adults

BACKGROUND

Automated systems use closed-loop control to enable ventilators to perform basic and advanced functions while supporting respiration. SmartCare™ is a unique automated weaning system that measures selected respiratory variables, adapts ventilator output to individual patient needs by operationalizing predetermined algorithms and automatically conducts spontaneous breathing trials (SBTs) when predetermined thresholds are met.

OBJECTIVES

The primary objective of this review was to compare weaning time (time from randomization to extubation as defined by study authors) between invasively ventilated critically ill adults weaned by automated weaning and SBT systems versus non-automated weaning strategies.As secondary objectives, we ascertained differences between effects of alternative weaning strategies on clinical outcomes (time to successful extubation, time to first SBT and first successful SBT, mortality, ventilator-associated pneumonia, total duration of ventilation, lengths of intensive care unit (ICU) and hospital stay, use of non-invasive ventilation (NIV), adverse events and clinician acceptance).The third objective of our review was to use subgroup analyses to explore variations in weaning time, length of ICU stay, mortality, ventilator-associated pneumonia, use of NIV and reintubation according to (1) the type of clinician primarily involved in implementing the automated weaning and SBT strategy, (2) the ICU (as a reflection of the population involved) and (3) the non-automated (control) weaning strategy utilized.We conducted a sensitivity analysis to evaluate variations in weaning time based on (4) the methodological quality (low or unclear versus high risk of bias) of the included studies.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) 2013, Issue 5; MEDLINE (1966 to 31 May 2013); EMBASE (1988 to 31 May 2013); the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to 31 May 2013), Evidence-Based Medicine Reviews and Ovid HealthSTAR (1999 to 31 May 2013), as well as conference proceedings and trial registration websites; we also contacted study authors and content experts to identify potentially eligible trials.

SELECTION CRITERIA

Randomized and quasi-randomized trials comparing automated weaning and SBT systems versus non-automated weaning strategies in intubated adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and abstracted data according to prespecified criteria. Sensitivity and subgroup analyses were planned to assess the impact on selected outcomes of the following: (1) the type of clinician primarily involved in implementing automated weaning and SBT systems, (2) the ICU (as a reflection of the population involved) and (3) the non-automated (control) weaning strategy utilized.

MAIN RESULTS

We pooled summary estimates from 10 trials evaluating SmartCare™ involving 654 participants. Overall, eight trials were judged to be at low or unclear risk of bias, and two trials were judged to be at high risk of bias. Compared with non-automated strategies, SmartCare™ decreased weaning time (mean difference (MD) -2.68 days, 95% confidence interval (CI) -3.99 to -1.37; P value < 0.0001, seven trials, 495 participants, moderate-quality evidence), time to successful extubation (MD -0.99 days, 95% CI -1.89 to -0.09; P value 0.03, seven trials, 516 participants, low-quality evidence), length of ICU stay (MD -5.70 days, 95% CI -10.54 to -0.85; P value 0.02, six trials, 499 participants, moderate-quality evidence) and proportions of participants receiving ventilation for longer than seven and 21 days (risk ratio (RR) 0.44, 95% CI 0.23 to 0.85; P value 0.01 and RR 0.39, 95% CI 0.18 to 0.86; P value 0.02). SmartCare™ reduced the total duration of ventilation (MD -1.68 days, 95% CI -3.33 to -0.03; P value 0.05, seven trials, 521 participants, low-quality evidence) and the number of participants receiving ventilation for longer than 14 days (RR 0.61, 95% CI 0.37 to 1.00; P value 0.05); however the estimated effects were imprecise. SmartCare™ had no effect on time to first successful SBT, mortality or adverse events, specifically reintubation. Subgroup analysis suggested that trials with protocolized (versus non-protocolized) control weaning strategies reported significantly shorter ICU stays. Sensitivity analysis excluded two trials with high risk of bias and supported a trend toward significant reductions in weaning time favouring SmartCare™.

AUTHORS' CONCLUSIONS

Compared with non-automated weaning strategies, weaning with SmartCare™ significantly decreased weaning time, time to successful extubation, ICU stay and proportions of patients receiving ventilation for longer than seven days and 21 days. It also showed a favourable trend toward fewer patients receiving ventilation for longer than 14 days; however the estimated effect was imprecise. Summary estimates from our review suggest that these benefits may be achieved without increasing the risk of adverse events, especially reintubation; however, the quality of the evidence ranged from low to moderate, and evidence was derived from 10 small randomized controlled trials.

Predicting extubation failure in blunt trauma patients with pulmonary contusion

BACKGROUND

The need for reintubation after weaning from mechanical ventilation (extubation failure) is associated with increased morbidity and mortality. In blunt trauma patients with pulmonary contusion, factors predicting successful weaning have not been reliably defined. The purpose of this study was to identify criteria predicting successful extubation in these patients.

METHODS

Retrospective review during a 10-year period at a Level 1 trauma center was performed. A total of 173 extubations in 163 blunt trauma patients with pulmonary contusion requiring mechanical ventilation. Exclusion criteria include Glasgow Coma Scale (GCS) score of less than 9T before extubation, successful use of noninvasive positive-pressure ventilation after extubation, quadriplegia, and preextubation FIO2 of greater than 0.5. Data included age, Injury Severity Score (ISS), ventilator days, as well as GCS score, FIO2, the ratio of arterial oxygen tension to FIO2 (P/F ratio), and alveolar-arterial oxygen (A-a) difference at the time of extubation. Failure was defined as reintubation within 72 hours (excluding stridor or acute decline in GCS score). Mann-Whitney U-test, χ2 analysis, and logistic regression analysis determined variables associated with extubation failure. Odds ratios were used to compare P/F and A-a values associated with failed extubation.

RESULTS

A total of 147 extubations (85%) were successful; 26 required reintubation. Patients did not differ by ISS, chest Abbreviated Injury Scale (AIS) score, presence of sternal or rib fractures, and admission pneumothorax or hemothorax. Increased age, A-a difference (≥ 120 mm Hg), and decreased P/F (<280) were associated with reintubation (p < 0.0001). By logistic regression analysis, P/F and A-a were independent variables for failed extubation; both remained independent risk factors when adjusted for age, ventilator days, GCS score, and preextubation FIO2. Using receiver operating characteristic curve inflection points for both P/F and A-a difference (area under the curve of 0.8 for both), patients with a P/F ratio less than 290 and an A-a difference of 100 mm Hg or greater were more likely to fail extubation (odds ratio, 9.2 and 8.7, respectively, p < 0.001).

CONCLUSION

Blunt trauma patients with pulmonary contusion who are likely to fail extubation can be reliably identified using the readily available criteria of P/F ratio less than 290 and A-a difference of 100 mm Hg or greater.

Use of weaning protocols for reducing duration of mechanical ventilation in critically ill adult patients: Cochrane systematic review and meta-analysis

OBJECTIVE

To investigate the effects of weaning protocols on the total duration of mechanical ventilation, mortality, adverse events, quality of life, weaning duration, and length of stay in the intensive care unit and hospital.

DESIGN

Systematic review.

DATA SOURCES

Cochrane Central Register of Controlled Trials, Medline, Embase, CINAHL, LILACS, ISI Web of Science, ISI Conference Proceedings, Cambridge Scientific Abstracts, and reference lists of articles. We did not apply language restrictions. Review methods We included randomised and quasi-randomised controlled trials of weaning from mechanical ventilation with and without protocols in critically ill adults. Data selection Three authors independently assessed trial quality and extracted data. A priori subgroup and sensitivity analyses were performed. We contacted study authors for additional information.

RESULTS

Eleven trials that included 1971 patients met the inclusion criteria. Compared with usual care, the geometric mean duration of mechanical ventilation in the weaning protocol group was reduced by 25% (95% confidence interval 9% to 39%, P=0.006; 10 trials); the duration of weaning was reduced by 78% (31% to 93%, P=0.009; six trials); and stay in the intensive care unit length by 10% (2% to 19%, P=0.02; eight trials). There was significant heterogeneity among studies for total duration of mechanical ventilation (I(2)=76%, P<0.01) and duration of weaning (I(2)=97%, P<0.01), which could not be explained by subgroup analyses based on type of unit or type of approach.

CONCLUSION

There is evidence of a reduction in the duration of mechanical ventilation, weaning, and stay in the intensive care unit when standardised weaning protocols are used, but there is significant heterogeneity among studies and an insufficient number of studies to investigate the source of this heterogeneity. Some studies suggest that organisational context could influence outcomes, but this could not be evaluated as it was outside the scope of this review.

Research priorities of adult intensive care nurses in 20 European countries: a Delphi study

AIMS

This paper is a report of a three round Delphi study of intensive care nursing research priorities in Europe (October 2006-April 2009).

BACKGROUND

Internationally, priorities for research in intensive care nursing have received some attention focusing on healthcare interventions and patient needs. Studies as early as the 1980s identified priorities in the United States, United Kingdom, Hong Kong and Australia. Research priorities of intensive care nurses across the European Union are unknown.

METHODS

The participants, invited in 2006, included 110 intensive care nurses, managers, educators and researchers from 20 European Critical Care Nursing Associations. Delphi round one was an emailed questionnaire inviting participants to list important areas for research. The list was content analysed and developed into an online questionnaire for rounds two and three. In round two, participants ranked the topics on a scale of 1-6 (not important to extremely important). Mean scores of round two were added to the questionnaire of round three and participants ranked the topics again.

RESULTS

There were 52 research topics in 12 domains. There was a dominance of priorities in five main areas: patient safety; impact of evidence based practice on outcomes; impact of workforce on outcomes; wellbeing of patients and relatives; and impact of end-of-life care on staff and practice.

CONCLUSIONS

The results reflect worldwide healthcare concerns and objectives and highlight topics that nurses view as fundamental to the care of critically ill patients. These topics provide a platform for future research efforts to improve clinical practice and care of patients in intensive care.

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.

Protocolized vs. non-protocolized weaning for reducing the duration of mechanical ventilation in critically ill adult patients: Cochrane review protocol

AIM

This paper is a report of the protocol for a review to identify, critically appraise and synthesize the best current evidence supporting the use of weaning protocols compared to non-protocolized practice in liberating patients from mechanical ventilation.

BACKGROUND

Patients experiencing difficulty in weaning require a longer hospital stay and have higher morbidity and mortality. Consequently, efforts to reduce weaning time are desirable to reduce the duration of ventilation and related complications. Standardized weaning protocols are safe and effective in reducing the time spent on mechanical ventilation.Notwithstanding, the evidence supporting their use in practice is inconsistent. The discordant results of studies may reflect the fact that protocols vary in composition and are implemented in different environments by various healthcare providers.

DESIGN

The objectives of this review are to compare the total duration of mechanical ventilation between patients weaned using protocols vs. non-protocolized practice; to ascertain differences between protocolized and non-protocolized weaning with regards to mortality, adverse events, quality of life, weaning duration, ICU and hospital stay; and to explore variation in outcomes by the type of ICU, the type of protocol and approach to delivering the protocol. We will search the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE, CINAHL, ISI Web of Science and LILACS. In addition, we will endeavour to identify unpublished data and contact first authors of studies included in the review to obtain information on unpublished studies or work in progress.

CONCLUSION

This review will provide much needed direction for healthcare professionals in intensive care in terms of both research and practice.

An evaluation of protocolised weaning on the duration of mechanical ventilation

Using a before and after study design, we compared protocolised weaning from mechanical ventilation with usual non-protocolised practice in intensive care. Outcomes (duration of mechanical ventilation, duration of intubation, intensive care stay) and complications (re-intubations, tracheostomy, mortality) were compared between baseline (Phase I) and following implementation of protocolised weaning (Phase II). Over the same period, we collected data in a second (reference) unit to monitor practice changes over time. In the intervention unit, outcomes were longer in Phase II compared with Phase I (all p < 0.005). When adjusted for admission APACHE II score and diagnostic category, only intensive care stay remained significantly longer (p = 0.002). There were significantly more tracheostomies in Phase II (p = 0.004). The reference unit demonstrated no statistically significant differences in study outcomes or complications between Phases. Protocolised weaning did not reduce the duration of mechanical ventilation and was not associated with an increased rate of re-intubation or intensive care unit mortality.

Protocolized weaning from mechanical ventilation: ICU physicians' views

BACKGROUND

The use of protocols during weaning from mechanical ventilation is uncommon in the UK, despite research pointing to their potential benefits. This may be because the research evidence is considered not to apply in different settings. Intensive care unit consultant physicians are the major decision-makers in weaning in the UK and any attempt to introduce protocolized weaning will require consideration of their views.

AIM

The aim of this paper is to report a study exploring intensive care physicians' views on (i) weaning from mechanical ventilation, (ii) the utility of weaning protocols and (iii) nurses' roles in the weaning process. A specific goal was to identify potential aids and barriers to developing weaning protocols and their introduction into clinical practice.

METHODS

Qualitative interviews were conducted with a purposive sample of 10 consultant physicians in two intensive care units in Northern Ireland and subjected to content analysis.

FINDINGS

The primary themes identified were (i) information required for weaning decisions and clinical judgement, (ii) professional boundaries, (iii) protocol issues and (iv) timing of weaning. Three types of information were deemed to be required for weaning decisions - empirical objective, empirical subjective and abstract - and interviewees considered that it would be challenging to incorporate all into a protocol. They were divided on whether protocols were useful when nursing experience was limited. Some groups of patients were thought more suitable than others for protocolized weaning.

CONCLUSIONS

Although local physicians were supportive in theory, introduction of protocolized weaning is likely to be difficult because of the breadth of information required for successful decision-making. Consultant views in this study were not consistent with American findings that physicians' caution may unnecessarily prolong weaning.

Role of the tissue factor pathway in the pathogenesis and management of multiple organ failure

Sepsis is caused by a dysregulated immune response to infection and, without intervention, can lead to septic shock and multiple organ failure. A leading cause of morbidity and mortality in intensive care units worldwide, severe sepsis is also associated with a considerable cost burden that places significant strain on global healthcare budgets. The development of an efficacious and cost-effective treatment strategy is therefore of vital importance to today's intensive care physicians. This paper will examine the pathophysiology of sepsis and multiple organ dysfunction before reviewing trials recently undertaken to investigate three potential anticoagulant therapies: antithrombin III, activated protein C, and tissue factor pathway inhibitor. Finally, other recent developments in the care of sepsis patients will be briefly examined.

A study exploring factors which influence the decision to commence nurse-led weaning

Nurse-led weaning can improve patient outcome. Exploration of the factors that influence the commencement of weaning. Themes of decision-making, pathophysiological and multidisciplinary team factors emerged. Experience was a key factor in the decision to wean. The use of protocol-led weaning may not be useful in the decision to wean.

Factors influencing the patient during weaning from mechanical ventilation: a national survey

Successful weaning depends on the application of skilled judgement and decision making to nursing and medical interventions. The intensive care nurse is in an unique position for adopting a holistic approach to weaning. Such an approach needs teamwork and consideration of all the factors that could influence the outcome of the weaning phase. The aim of this study was to conduct a survey, to establish the factors taken into consideration and documented during weaning at the intensive care units (ICUs) in Sweden. A questionnaire was developed and sent to all 92 ICUs. The results identified that nutrition, communication, analgesics and sedatives, psychological and metabolic factors, as well as weaning methods and measurable parameters were taken into consideration. Written instructions for weaning were used by only three ICUs and weaning protocols were not common. A holistic approach to the discontinuation of mechanical ventilation is a valuable means of improving the quality of care and merits further research.

Effects of pressure support ventilation and continuous positive airway pressure on diaphragm performance

Many patients who are on mechanical ventilation are on ventilator modes called pressure support ventilation (PSV) and continuous positive airway pressure (CPAP) particularly when they are being weaned. As the diaphragm is responsible for approximately 75% of breathing, it is important to promote diaphragm shortening to optimize weaning from mechanical ventilation. The purpose of our 1998 quasi-experimental study was to explore the effects of PSV and CPVP on diaphragm shortening. An animal model was utilized using four Sprague-Dawley rats from the same litter purchased from Sasco (Kansas City, USA). Also measured in this study were intrathoracic pressure (DeltaITP), positive inspiratory pressure, respiratory rate, tidal volume, end-tidal carbon dioxide, central venous pressure (CVP) and mean arterial pressure (MAP). Pressure support was increased in increments of 5 cm H2O at CPAP levels of 0, 2 and 4 cm H2O. A direct assessment of diaphragm shortening was achieved through the adherence of a miniaturized ultrasonic sensor to the inferior surface of the middle costal surface of the right hemidiaphragm of four Sprague-Dawley rats. Limitations of this study included a small sample size, anaesthetized rats and abdominal dissection for insertion of the ultrasonic sensor. As PSV was increased, there was a decrease in MAP, CVP, respiratory rate and end-tidal CO2. When increasing levels of CPAP were added to PSV, a decrease in diaphragm shortening was observed. These results support that higher levels CPAP may hinder diaphragmatic function thus prolong mechanical ventilation. The purpose of this pilot study was to explore the effects of PSV and CPAP on diaphragm shortening. Also measured were DeltaITP, positive inspiratory pressure, respiratory rate, tidal volume, end-tidal carbon dioxide, CVP and MAP. Pressure support was increased in increments of 5 cm H2O at CPAP levels of 0, 2 and 4 cm H2O. A direct assessment of diaphragm shortening was achieved through the adherence of a miniaturized ultrasonic sensor to the inferior surface of the middle costal surface of the right hemidiaphragm of four Sprague-Dawley rats. Limitations of this study included a small sample size, anaesthetized rats and abdominal dissection for insertion of the ultrasonic sensor. As PSV was increased, there was a decrease in MAP, CVP, respiratory rate and end-tidal CO2. When increasing levels of CPAP were added to PSV, a decrease in diaphragm shortening was observed.

The art and science of predicting patient readiness for weaning from mechanical ventilation

Weaning from mechanical ventilation is attempted when the patient's underlying condition has resolved and when the patient is able to maintain cardiovascular and respiratory stability within normal parameters. From a medical perspective, when to wean is based on patient readiness determined by objective, physiological criteria. Psychological readiness is equally important, yet criteria determining psychological readiness is generally omitted from the list of ready to wean parameters. Reasons for this may be that psychological readiness is difficult to measure and is based upon subjective opinions. Nursing research exploring critical care nurses' and patients' experiences of weaning has extended knowledge concerning patients' psychological readiness to wean. From examination of this research, three important criteria emerge. It is recommended that the addition of these criteria to the list of physiological criteria will not only achieve a holistic assessment of patients' readiness to wean, but will also acknowledge the important and complementary role of the nurse in the weaning process.