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Commentary on: Hulzebos EH, Smit Y, Helders PP, et al. Preoperative physical therapy for elective cardiac surgery patients. Cochrane Database Syst Rev 2012;11:CD010118.
Implications for practice and research
Cardiac surgery patients are at risk of postoperative pulmonary complications.
The incidence of postoperative pulmonary complications varies in the literature, because of inconsistent definitions for postoperative pulmonary complication.
More large-scale randomised controlled trials are needed to determine the value of preoperative physical therapy in cardiac surgery patients.
Postoperative pulmonary complications are a common cause of morbidity and mortality after cardiac surgery. The reasons for the lung function impairment are multifactorial and include anaesthesia, cardiopulmonary bypass, the surgery itself, analgesia and postoperative immobility. The reported incidence varies in the literature, depending on the specific criteria used for the definition of a postoperative pulmonary complication and the diagnostic techniques used to detect them. Efforts have been made to identify those patients who have a higher risk of developing postoperative pulmonary complications. Physical therapy is often provided both preoperatively and postoperatively to prevent or reduce these complications. While the benefit of postoperative physical therapy interventions has been well documented during the recent years, there are few reports on the value of preoperative physical therapy.
In this Cochrane systematic review, Hulzebos and colleagues evaluate the efficacy and safety of preoperative physical therapy to prevent postoperative pulmonary complications after cardiac surgery. Eight randomised or quasi-randomised controlled trials evaluating preoperative physical therapy that comprised an exercise component (breathing exercises or aerobic exercises) were included. A similar postoperative physical therapy regimen in both the treatment group and control was a criterion for inclusion. In addition, the authors wanted to know if the effectiveness differed in low-risk compared to high-risk patients. The following databases were searched for relevant studies: CENTRAL, MEDLINE, EMBASE, PEDro and CINAHL. Primary outcomes were the occurrence of postoperative pulmonary complications, all-cause mortality and adverse events. Secondary outcomes were length of postoperative hospital stay (LoS), physical function measures, postoperative respiratory mortality, health-related quality of life (HRQoL) and costs.
The authors evaluated five trials of inspiratory muscle training with a threshold loading device and three trials of a mixed intervention (short-term pulmonary rehabilitation, multidimensional preoperative intervention, holistic therapy including exercises and stress reduction). A total of 856 patients were evaluated. The authors conclude that preoperative physical therapy decreased atelectasis (four studies), decreased incidence of pneumonia (five studies), decreased LoS (three studies) and improved HRQoL (one study). Pneumothorax, mechanical ventilation time and all-cause postoperative death was not significantly decreased in patients receiving preoperative physical therapy compared to controls. The small number of studies per outcome precluded subgroup analysis of high-risk versus low-risk patients.
In the present review, Hulzebos and colleagues address the interesting and much debated question of the utility of preoperative physical therapy. The strength of this study was the attention it brought to patients who may be at increased risk for postoperative pulmonary complications. Unfortunately, the number of trials was too less to compare the effectiveness of therapy for patients at high risk with patients at low risk. While trying to establish reasons for an increased risk, using only preoperative data to identify patients as being at high or low risk is problematic since surgery and perioperative data as well are the important reasons to consider.1
Different physical therapy techniques with different intensity and duration were evaluated, with a variety of outcome measures. The authors used the classification by Kroenke et al2 for the operational definition of a clinically significant postoperative pulmonary complication. In addition to cough, atelectasis, hypoxaemia, pneumonia and bronchospasm, the definition includes symptoms such as adverse reactions to pulmonary medication, pleural effusion and pneumothorax. The outcomes are clinically relevant, but reliable measurements may be difficult to accomplish. CT-verified atelectasis can be detected in all patients undergoing cardiac surgery while the absolute amount of atelectasis that may predict poor outcome is debatable. In the included trials, atelectasis was presented as a dichotomous outcome from ordinary chest x-rays and no clear definition of pneumonia was given in several of the trials.
In conclusion, a more critical approach regarding the inclusion of trials is warranted. The three trials including different mixed interventions may be difficult to summarise in a systematic way. As the authors conclude, future studies should consider a uniform definition of postoperative pulmonary complications. At present, limited data is available to support the use of specific preoperative physical therapy interventions for the prevention of postoperative pulmonary complications in cardiac surgery patients. More well-designed randomised trials are needed to clearly ascertain the impact of preoperative physical therapy.
Competing interests None.
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