Psychological interventions for acute pain after open heart surgery
This is an update of a Cochrane review previously published in 2014. Acute postoperative pain is one of the most disturbing complaints in open heart surgery, and is associated with a risk of negative consequences. Several trials investigated the effects of psychological interventions to reduce acute postoperative pain and improve the course of physical and psychological recovery of participants undergoing open heart surgery.
To compare the efficacy of psychological interventions as an adjunct to standard care versus standard care alone or standard care plus attention control in adults undergoing open heart surgery for pain, pain medication, psychological distress, mobility, and time to extubation.
For this update, we searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Web of Science, and PsycINFO for eligible studies up to February 2017. We used the 'related articles' and 'cited by' options of eligible studies to identify additional relevant studies. We checked lists of references of relevant articles and previous reviews. We searched the ProQuest Dissertations and Theses Full Text Database, ClinicalTrials and the WHO International Clinical Trials Registry Platform to identify any unpublished material or ongoing trials. We also contacted the authors of primary studies to identify any unpublished material. In addition, we wrote to all leading heart centres in Germany, Switzerland, and Austria to check whether they were aware of any ongoing trials.
Randomised controlled trials comparing psychological interventions as an adjunct to standard care versus standard care alone or standard care plus attention in adults undergoing open heart surgery.
Data collection and analysis
Two review authors (SZ and SK) independently assessed trials for eligibility, estimated the risk of bias and extracted all data. We calculated effect sizes for each comparison (Hedges’ g) and meta‐analysed data using a random‐effects model. We assessed the evidence using GRADE and created 'Summary of findings' tables.
We added six studies to this update. Overall, we included 23 studies (2669 participants).
For the majority of outcomes (two‐thirds), we could not perform a meta‐analysis since outcomes were not measured, or data were provided by one trial only.
No study reported data on the number of participants with pain intensity reduction of at least 50% from baseline. Only one study reported data on the number of participants below 30/100 mm on the Visual Analogue Scale (VAS) in pain intensity (very low‐quality evidence). Psychological interventions did not reduce pain intensity in the short‐term interval (g 0.39, 95% CI ‐0.18 to 0.96, 2 studies, 104 participants, low‐quality evidence), medium‐term interval (g ‐0.02, 95% CI ‐0.24 to 0.20, 4 studies, 413 participants, moderate‐quality evidence) or in the long‐term interval (g 0.05, 95% CI ‐0.20 to 0.30, 2 studies, 200 participants, moderate‐quality evidence).
No study reported data on median time to re‐medication or on number of participants re‐medicated. Only two studies provided data on postoperative analgesic use in the short‐term interval, showing that psychological interventions did not reduce the use of analgesic medication (g 1.18, 95% CI ‐2.03 to 4.39, 2 studies, 104 participants, low‐quality evidence). Studies revealed that psychological interventions reduced mental distress in the medium‐term (g 0.37, 95% CI 0.13 to 0.60, 13 studies, 1388 participants, moderate‐quality evidence) and likewise in the long‐term interval (g 0.32, 95% CI 0.10 to 0.53, 14 studies, 1586 participants, moderate‐quality evidence). Psychological interventions did not improve mobility in the medium‐term interval (g 0.23, 95% CI ‐0.22 to 0.67, 3 studies, 444 participants, low‐quality evidence), nor in the long‐term interval (g 0.09, 95% CI ‐0.10 to 0.28, 4 studies, 458 participants, moderate‐quality evidence). Only two studies reported data on time to extubation, indicating that psychological interventions reduced the time to extubation (g 0.56, 95% CI 0.08 to 1.03, 2 studies, 154 participants, low‐quality evidence).
Overall, the very low to moderate quality of the body of evidence on the efficacy of psychological interventions for acute pain after open heart surgery cannot be regarded as sufficient to draw robust conclusions.
Most 'Risk of bias' assessments were low or unclear. We judged selection bias (random sequence generation) and attrition bias to be mostly low risk for included studies. However, we judged the risk of selection bias (allocation concealment), performance bias, detection bias and reporting bias to be mostly unclear.
In line with the conclusions of our previous review, there is a lack of evidence to support or refute psychological interventions in order to reduce postoperative pain in participants undergoing open heart surgery. We found moderate‐quality evidence that psychological interventions reduced mental distress in participants undergoing open heart surgery. Given the small numbers of studies, it is not possible to draw robust conclusions on the efficacy of psychological interventions on outcomes such as analgesic use, mobility, and time to extubation respectively on adverse events or harms of psychological interventions.
Susanne Ziehm, Jenny Rosendahl, Jürgen Barth, Bernhard M Strauss, Anja Mehnert, Susan Koranyi
Plain language summary
Psychological treatments to reduce pain in people undergoing open heart surgery
Acute postoperative pain is one of the most disturbing complaints after open heart surgery. It is related to impaired wound healing, chronic pain, or depression. Psychological treatment is designed to improve participant’ knowledge and to alter surgery‐related mental distress, negative beliefs and noncompliance. It aims to reduce pain and anxiety, and to improve the postoperative recovery after open heart surgery.
This is an update of a review previously published in 2014 investigating whether psychological treatment could successfully reduce acute postoperative pain and improve the course of physical and psychological recovery of people undergoing open heart surgery.
We found 23 studies, including a total of 2669 participants, which reported effects of psychological treatment compared to a control group without psychological treatment on pain intensity, use of pain medication, mental distress, mobility, or time to extubation after surgery.
Key findings and quality of evidence
We rated the quality of the evidence from studies using four levels: very low, low, moderate, or high. Very low‐quality evidence means that we are very uncertain about the results. High‐quality evidence means that we are very confident in the results.
We do not know if psychological treatment reduces pain intensity, enhances mobility, or decreases intubation time after open heart surgery. This is because there were not enough data to answer some parts of our review question, because there were problems with the design of some studies, or because results were conflicting. We only found very low to moderate‐quality evidence for these outcomes.
We found moderate‐quality evidence that psychological treatment could reduce mental distress. This means that we are moderately certain about the results because there were psychological treatments that clearly reduced distress whereas others did not.
The evidence in our review is current to February 2017.
Susanne Ziehm, Jenny Rosendahl, Jürgen Barth, Bernhard M Strauss, Anja Mehnert, Susan Koranyi
Implications for practice
For people with acute pain after open heart surgery
There is no evidence that psychological interventions reduce postoperative pain in people undergoing open heart surgery. Limited data were available and future studies are likely to change the conclusions reported here. There was moderate quality of evidence that psychological interventions reduced mental distress. Analyses revealed no effects of psychological interventions to enhance mobility or to reduce the time to extubation. Again, there was considerable uncertainty around these conclusions due to limited data.
We found that psychological interventions which were delivered face‐to‐face in a one‐to‐one setting were highly effective in reducing mental distress (Dao 2011; De Klerk 2004; Parent 2000; Zarea 2014). In addition, a considerable reduction of mental distress was achieved with multiple therapeutic contacts instead of one visit only. Also, clinicians should accompany, if possible, people after discharge as well to retain the positive intervention effects on mental distress reduction. No intervention method (e.g. psychoeducation, relaxation or cognitive‐behavioural approach) was superior to others or less effective than other intervention methods.
For policy makers and funders of the intervention
The current evidence does not clearly support the use of psychological interventions to reduce postoperative pain. However, there was moderate‐quality evidence that psychological interventions could reduce postoperative mental distress. Moreover, psychological interventions seemed to be cost‐effective and quite easy to implement.
Implications for research
The majority of studies did not provide information about skills or competence of the treatment provider (e.g. formal qualification or training). Training and qualifications, as well as checking that sessions conform to the named treatment methods, are important aspects of quality assurance, as psychological interventions rely very much on the skills of the practitioner. Future trials should describe the qualifications and training of the staff, and should include session checks on competence and adherence in their study design.
It might be reasonable to assume the presence of participant variables which moderate the effects of psychological interventions. Thus, future study designs should investigate moderating variables. For example, it has been shown for people with cancer that those with higher levels of mental distress may benefit more from psychological interventions than those with normal levels of mental distress, or those with only a marginally increased level (Coyne 2006; Hart 2012). There are further findings indicating that control appraisals do moderate the effect of psychoeducational interventions on distress and pain (Shelley 2007). There might be subgroups of participants who are unaffected or who even experience more distress after the intervention than they would have experienced without it. Future studies should report results for subgroups of participants in order to examine differential effects.
Future study designs should also focus on the underlying mechanisms of psychological interventions in the context of cardiac surgery, as these mechanisms are not yet understood. One possible underlying mechanism might be participants' adherence to medical treatment recommendations. It might be reasonable to expect that people undergoing open heart surgery with reduced mental distress after surgery are more adherent to medical treatments, recommendations for lifestyle change and participation in cardiac rehabilitation, as has already been shown for people recovering from acute coronary events (Glazer 2002; Rieckmann 2006; Sin 2016; Ziegelstein 2000). Understanding how psychological interventions work is crucial to designing psychological interventions that target active change mechanisms.
The large heterogeneity in effects on mental distress needs to be explained in future research. Some studies yielded very large positive effects on the reduction of mental distress, and some studies showed no effects of psychological interventions on mental distress. Considering only studies with very large positive effect sizes (Dao 2011; De Klerk 2004; Parent 2000; Zarea 2014), we detected that multiple face‐to‐face contacts in one‐to‐one settings, which are extended beyond discharge seem to be specifically effective in reducing postoperative mental distress. These aspects (longer treatment duration and psychological treatment even after discharge) might lead to a more profound therapeutic relationship, which is one of the most important factors to influence treatment outcome (Lambert 2001) and could therefore explain the beneficial effects; these should therefore be in the scope of future studies.
Future trials should test the extent to which psychological interventions contribute any specific effects above and beyond the nonspecific effects of additional attention and caring support received during hospitalisation. Thus, more clinical trials with attention control group as comparators in their study design are needed (e.g. Akgul 2016; Rief 2017).
For the majority of outcomes (two‐thirds), we could not perform a meta‐analysis because either the outcomes were not measured, or data were only provided by one trial. Since our review was limited by a lack of data for primary and secondary outcomes (particularly dichotomous pain outcome data), future trials which report adequate pain outcomes are urgently needed.
The quality of evidence for benefits of psychological interventions on mental distress was moderate. The meta‐analysis results suggested that psychological interventions might have the potential to enable participants to cope successfully with stresses of open heart surgery. Successful coping prevents the development of an adjustment disorder or a reactive type of depression, which in turn have been hypothesised to be associated with the aetiology of postoperative depression (Peterson 2002). Several studies have demonstrated an association between postoperative depression and mortality or cardiac events after cardiac surgery, although the behavioural and biological mechanisms are as yet poorly understood (see for a review Tully 2012; Tully 2015). Further studies are required to evaluate the long‐term effects of in‐hospital psychological interventions in people undergoing cardiac surgery on the development of postoperative depression and subsequently occurring cardiac events.
In our meta‐analysis, we did not evaluate any harm associated with psychological interventions since none of the primary studies reported any adverse intervention effects. Adverse events might be of interest to the population of people undergoing open heart surgery, and should be collected in forthcoming trials, as studies in people after a critical life event have shown some negative effects of psychological interventions.