Background

Community acquired pneumonia (CAP), an infection of the lung tissue contracted outside of a healthcare facility or within 48 hours of admission to hospital, is the most common infectious disease causing death and poses a large burden on healthcare systems and communities worldwide.1-4 Community acquired pneumonia requires hospitalization in 20% of cases,6 particularly for persons above 65 years of age,2 the Indigenous7 and those with chronic disease,2,5 and these factors are associated with worse outcomes.1,3 Australian data indicate that 10-35% of patients with CAP require admission to an intensive care unit (ICU) due to respiratory failure and septic shock resulting from severe infection,6,8 and mechanical ventilation is necessary in 73% of these cases.6

The mortality rate of patients admitted to ICU for CAP is 20-50% worldwide,3,6,9,10 despite advances in medical science over the last four decades1,6,8 and adequate initiation of antibiotic treatment.10,11 A study from Western Australia indicated that 89% of CAP deaths occur within 90 days of ICU admission, and death following hospital discharge is common and strongly correlated with illness severity.12 Survivors of CAP have an increased mortality rate for the two to five years following hospital discharge compared to age- and gender-matched control subjects.1

Physiotherapists working in the ICU commonly provide intervention for mechanically ventilated patients with respiratory illness, such as pneumonia, with the aim of facilitating airway clearance, optimizing pulmonary mechanics, improving gas exchange and facilitating weaning from mechanical ventilation and functional recovery.13-15 However, the physiotherapy literature regarding the management of intubated, critically ill patients with pneumonia, and in particular CAP is scant and therefore clinicians have little guidance to inform best practice.16,17 As a result, clinical practice is observed to be variable regarding the type, duration and frequency of intervention delivered to facilitate airway clearance, improve respiratory mechanics and enhance functional recovery for these patients. Studies have shown that manual hyperinflation (MHI), a technique often used by physiotherapists in the critical care settings to treat the lungs, when performed in side-lying with the affected lung uppermost, significantly improved lung compliance by 11-30%18-20 and significantly increased secretion clearance by up to 59%18 in mixed ICU cohorts. Further studies have established that MHI and ventilator hyperinflation (VHI) are equivocal for improving lung compliance and secretion clearance19,21,22 in mixed ICU cohorts. Only two studies to date have examined the effects of hyperinflation techniques on respiratory mechanics specifically in patients with pneumonia.23,24 Choi and Jones23 demonstrated significant improvement in lung compliance (22%, P < 0.001) and significant reduction in airway resistance (21%, P = 0.004) following MHI in 15 intubated subjects with ventilator-associated pneumonia. Further, Lemes et al.24 demonstrated significant improvement in lung compliance (4.7 mL/cmH₂O, 95% confidence interval [CI] 2.6-6.8) and secretion clearance (1.3 mL, 95% CI 0.5-2.2) following VHI in side-lying, in 30 intubated and ventilated subjects with pneumonia (ventilator acquired 77%, community acquired 13% and hospital acquired 10%). However, these studies did not investigate the effects of such improvements on patient outcomes, such as ventilator time, speed of functional recovery, ICU and hospital length of stay.

A search of the Cochrane Database of Systematic Reviews, PROSPERO and the JBI Database of Systematic Reviews and Implementation Reports found only one review on respiratory physiotherapy for adults with pneumonia, conducted by Yang et al.25 However, this review excluded studies involving intubated and mechanically ventilated subjects. There were no other reviews found regarding physiotherapy for the management of pneumonia in mechanically ventilated ICU subjects. The objective of this review is therefore to synthesize the best available evidence on the effectiveness of respiratory physiotherapy interventions on outcomes for intubated and mechanically ventilated adults with CAP.

Inclusion criteria

Types of participants

Studies will be considered for inclusion in the review if participants are aged 18 years or over, have any diagnosis of pneumonia (based on radiological changes and/or positive sputum culture), are intubated with an artificial airway (either endotracheal or tracheostomy tube) and are receiving either partial or complete respiratory assistance from a mechanical ventilator. Studies will be excluded if participants are children aged under 18 years, are spontaneously breathing without a mechanical ventilator, or who are receiving non-invasive ventilation. Where studies describe participants who are younger than 18 years, they will be included if the median age of the group is 18 years or over. Studies that describe participants receiving either invasive or non-invasive mechanical ventilation will be included if the sub-groups with invasive ventilation have outcomes that can be extracted separately.

Types of intervention(s)/phenomena of interest

Studies investigating the effect of a respiratory physiotherapy intervention(s) for this population with the intervention(s) involving, but not limited to, positioning, gravity-assisted drainage, MHI, VHI, percussion and/or chest wall vibrations/expiratory rib cage compressions will be considered for inclusion. Studies that combine any of the above respiratory physiotherapy interventions with early mobilization or exercise will be excluded due to confounding effects on outcomes.

Types of comparators

Studies that examine the efficacy of respiratory physiotherapy interventions will be compared using a passive comparison (standard treatment in patients with pneumonia receiving mechanical ventilation) or an active comparison of one respiratory treatment regime with another will be considered for inclusion.

Outcomes

Studies will be included in this review if they investigate physiological outcomes of sputum volume or wet weight, lung compliance, airways resistance or oxygenation and/or morbidity outcomes of ventilation time, time taken to first stand or walk, length of ICU and/or hospital stay, health-related quality of life using the SF-3626 and/or mortality.

Types of studies

Studies considered for inclusion will be those that use an experimental design, either randomized or quasi-randomized, controlled trials or randomized cross-over trials and experimental studies where randomization has been used. Studies will only be included if they use repeated measures and compare an intervention against standard treatment, no treatment or another intervention.

Search strategy

The current review aims to identify all studies that have been written in English between 1995 and 2016 regarding respiratory physiotherapy management of intubated and mechanically ventilated patients with pneumonia, and CAP in particular. A review of physiotherapy in ICU published in 200016 reported that no evidence existed for the efficacy of respiratory physiotherapy in enhancing the clinical course of patients with pulmonary conditions, and since this time, a large body of literature has evolved regarding the burden of CAP. Gray literature and unpublished studies will also be considered for inclusion. This review will involve a three-step search strategy. The first preliminary search of MEDLINE and CINAHL Plus (EBSCO Information Services) with full text will be performed using the keywords: pneumonia, "chest or respiratory infection", physiotherap^*, "physical therap^*", hyperinflation, intubated, ventilated, "intensive care" and "critical care" and relevant studies retrieved. These studies will have titles and abstracts reviewed for keywords and/or MESH terms that will then be used for the second search using the following databases: MEDLINE, CINAHL Plus full text, Physiotherapy Evidence Database (PEDrO) and the Cochrane Database of Systematic Reviews. The articles identified for retrieval from the second search will have reference lists hand searched for relevant studies that had not been identified in the previous search rounds. All articles deemed suitable for retrieval from title, and abstract will be thoroughly examined by two independent investigators to determine relevance and suitability against the inclusion criteria. Where disagreement occurs between the two investigators regarding suitability for inclusion of the studies, a third investigator will arbitrate.

Assessment of methodological quality

The studies selected for retrieval will be independently assessed for methodological quality by two separate investigators prior to inclusion in the review, using standardized critical appraisal instruments from the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument (JBI-SUMARI).27 Any disagreements regarding suitability for inclusion will be resolved by discussion in the first instance and if resolution is not possible, a third investigator will be involved to mediate until consensus is reached.

Data extraction

Data extraction from the included studies will be conducted independently by two reviewers using the standardized data extraction tool from JBI-SUMARI and guided by information in the JBI critical appraisal tool for systematic reviews.27 The data extracted will include details about the populations, interventions, intervention comparators and outcomes of significance to the review objectives. If data are missing or unclear, the authors will contact the investigators to clarify the study findings.

Data synthesis

Quantitative data will, where possible, be pooled in statistical meta-analysis using JBI-SUMARI. All studies will be subjected to double data entry by two separate reviewers (LV and SP) and where discrepancies occur a third reviewer (A-MH) will be called to arbitrate. Effect sizes expressed as odds ratio (for categorical data) and weighted mean differences (for continuous data), and their 95% Confidence intervals will be calculated for analysis. Heterogeneity will be assessed statistically using the standard Chi-square. If data are available and can be pooled, sub-group analyses will be explored based on grouping trials that test an intervention(s) for a participant group(s) with CAP.

References