Abstract

Background: This study aims to investigate the efficacy of a specific physiotherapy protocol on the occurrence of postoperative pulmonary complications, length of intensive care unit (ICU) and hospital stay, and duration of intibutation in patients undergoing coronary artery bypass graft (CABG) surgery with variable postoperative pulmonary complication risk profiles.

Methods: Between June 2012 and October 2014, a total of 170 patients (116 males, 54 females; mean age 57.0±10.0 years; range 30 to 79 years) who underwent CABG surgery in our clinic were divided into two risk groups on the basis of their risk scores (low-risk ≤1 point or high-risk ≥2 point). A physiotherapy protocol consisted of four phases was performed from baseline until discharge. The incidence of postoperative pulmonary complications was scored by a blinded investigator on an ordinal scale of 1 to 4. Functional capacity was evaluated using a six-minute walk test (6MWT). Hospital Anxiety and Depression Scale (HADS) for anxiety and depression and Short Form-36 for quality of life were applied.

Results: The incidence of postoperative pulmonary complications, length of stay in the hospital and ICU and duration of intubation were not statistically significant in high-risk group, compared to the low-risk group (p>0.05). There was a significant decrease in 6MWA distance from baseline to discharge for all patients; however, the decline was lower in high-risk group. There was no statistically significant differences in the quality of life and depression scores between the groups after treatment (p>0.05). We observed statistically significant differences in anxiety scores between the groups after treatment (p<0.05).

Conclusion: This randomized, controlled trial demonstrated that physiotherapy might help patients in high-risk group for faster recovery after CABG. Physiotherapy is more critical in high-risk patients to obtain similar results as in low-risk group.

Despite technical and technological developments in recent years, the incidence of postoperative pulmonary complications (PPC) is over 30%.[1] Cardiopulmonary bypass usually causes lung injury, atelectasis, gas exchange abnormalities, pulmonary edema, and a reduction in respiratory function.[2] The PPC increases the morbidity, mortality, and duration of hospitalization, as well as care cost.[3]

Physiotherapy is used prophylactically to prevent and control the PPC after coronary artery bypass graft (CABG); however, there is no consensus on the optimal physiotherapy protocol in patients undergoing cardiac surgery. Also, the effects of these physiotherapy interventions on the occurrence of PPC and identifying patients who may benefit from such interventions are still controversial. Although the physiotherapy after heart surgery is recommended by guidelines, the routine physiotherapy is questioned in non-complicated patients.[4] The identification of optimal physiotherapy protocol and showing its efficiency in patients with different PPC risk scores can help to direct these interventions toward people who may benefit from such interventions and may reduce the incidence of PPC.

To the best of our knowledge, there is no study investigating the effects of a specific physiotherapy protocol after CABG in patients with variable PPC risk profiles. Several studies, to date, likely included patients without any comorbidities. Therefore, we aimed to investigate the efficacy of a specific physiotherapy protocol on the occurrence of PPC, length of intensive care unit (ICU) and hospital stay, and duration of intibutation in patients undergoing CABG surgery with variable PPC risk profiles.

Methods

We conducted a single-blinded randomized controlled trial. A total of 492 patients undergoing CABG surgery at the cardiovascular surgery unit of Gülhane Military Medicine Academy between June 2012 and October 2014 were enrolled. Inclusion criteria were age between 18 and 90 years and willing to participate by signing the written consent form. Exclusion criteria were as follows: other surgical procedures without associated CABG, history of a cerebrovascular accident, use of immunosuppressive medication within 30 days before surgery, and the presence of a neuromuscular disorder, cardiovascular instability, or an aneurysm. After screening, 170 patients (116 males, 54 females; mean age 57.0±10.0 years; range 30 to 79 years) were included in the study. The study protocol was approved by the Ethics Committee of the Gülhane Military Medicine Academy and was conducted in accordance with the principles of the Declaration of Helsinki.

Preoperative evaluation and risk stratification
Demographic characteristics, preoperative risk factors, and operative data were recorded. According to the definitions of the Society of Thoracic Surgeons[5,6] for the risk factors and the according to study of Hulzebos et al.,[7] the variables were scored to identify the risk of developing PPC (Table 1). The patients were divided into two risk groups on the basis of their scores (low-risk, ≤1 point; n=85 or high-risk ≥2 point; n=85). Then, these patients were either randomized to high-risk group or low-risk group by a computer-generated randomization table (Figure 1).

Table 1: Pulmonary risk score scale

Figure 1: Flow diagram of the study. PPC: Postoperative pulmonary complications.

Physiotherapy protocol
The interventions were performed by a team of physiotherapists who had no influence on the decisions related to the patient care, including extubation, ICU stay and hospital discharge. This program was only paused for surgery through to the day of extubation and it was re-started until the day of hospital discharge. The protocol was consisted of four phases (Appendix 1).

Appendix 1: BURANCAN-Cardiorespiratory Physiotherapy Protocol (BURANCAN-CrPT)

Primary outcomes
The incidence of PPC was scored by a blinded independent investigator on an ordinal scale of 1 to 4 (Table 2).[7] Anteroposterior chest X-ray was performed in the standing position preoperatively and on the discharge day. The presence or absence of atelectasis, infiltration, pneumothorax, pleural effusion, and pulmonary edema were recorded. An arbitrary scale was used to score atelectasis: 0, no abnormality; 1, minimal abnormality (plate atelectasis); 2, moderate abnormality (segmental atelectasis); 3, major abnormality (lobar atelectasis).[8] The postoperative length of ICU and postoperative hospital stay and duration of intibutation were obtained from the patients’ records.

Table 2: Definitions of postoperative pulmonary complications

Secondary outcomes
Functional exercise capacity was evaluated using a six-minute walk test (6MWT).[9] The 6MWT was performed preoperatively and was repeated on the fifth postoperative day. The patients were instructed to walk as far as possible within six minutes in an enclosed 30 m long hospital corridor. The maximum distance covered at the end of the test was recorded. The Turkish version of the Hospital Anxiety and Depression Scale (HADS) was applied for the evaluation of anxiety and depression. The HADS is a screening tool for anxiety and depression used in non-psychiatric clinical populations. It is divided into an Anxiety subscale (HADS-A) and a Depression subscale (HADS-D).[10] The health-related quality of life (HRQoL) was also assessed using the Turkish version of the 36-Item Short Form Health Survey (SF-36; first version), a selfadministered questionnaire, including 36 questions with eight different aspects: physical functioning, physical role functioning, bodily pain, general health, vitality, social functioning, emotional role functioning, and mental health.[11]

Statistical analysis
All statistical analyses were performed using SPSS version 16.0 statistical package (SPSS Inc., Chicago, IL, USA). Using the formula for sample size determination with a desired statistical power of 0.9, a medium effect size (d=0.50) and an alpha of 0.05, minimum sample size of 85 subjects for each group were calculated to reach statistical significance.[12] The Kolmogorov-Simirnov/Shapiro-Wilk test was used to analyze normally distributed continuous variables. The descriptive statistics were expressed in the mean ± standard deviation for the continuous variables and in number of patients and percent (%) for the categorical variables. Differences in nominal variables between the high-risk group and the lowrisk group were tested with the chi-square test. The Student t test was performed to compare the groups Paired t test was used to perform intragroup comparisons. A p value of <0.05 was considered statistically significant.

Results

Demographic characteristics, clinical characteristics, and perioperative data are shown in Table 3. Physiotherapy sessions were well tolerated without any complaints in all patients and no adverse effects occurred during the evaluation and treatment.

Table 3: Baseline characteristics of patients in high-risk and low-risk group

The results of primary outcomes were shown in Table 4. The incidence of PPC grades were not statistically significant in high-risk group, compared to the low-risk group (p>0.05). The length of stay in the hospital and ICU was not statistically significant between the high-risk and low-risk groups (p>0.05).

Table 4: Duration of postoperative hospitalization, intensive care unit and grade of postoperative pulmonary complications between the high-risk and low-risk groups

Preoperatively, the distance covered during 6MWT was significantly low in high-risk group, compared to the low-risk group (p<0.05) (Table 5). There was a significant decrease in 6MWA distance from preoperative to discharge for all patients; however, this decline was lower in high-risk group (Table 6). Therefore, there was no significant differences in the distance covered during 6MWT on the discharge day between the high-risk and low-risk groups after treatment (p>0.05).

Table 5: Comparison of preoperative functional capacity, anxiety, depression and quality of life scores

Table 6: Comparison of postoperative functional capacity, anxiety, depression and quality of life scores

Preoperatively and postoperatively, there was no significant differences in the HRQoL scores between the groups (p>0.05). Preoperatively, the depression and anxiety scores were similar between the groups. There was a significant decrease in anxiety scores from preoperative to discharge for all patients; however, this decline was much more in high-risk group (Table 5). There was no significant difference in depression scores between the groups after treatment (p>0.05) (Table 7).

Table 7: Effects of physiotherapy on functional capacity, anxiety, depression and quality of life scores

Discussion

In this study, we showed that our specific physiotherapy protocol had similar effects on the occurrence of PPC, postoperative length of ICU stay, duration of hospitalization, and intibutation and HRQoL in highrisk and low-risk groups after CABG surgery. Also, physiotherapy protocol is much more effective on the functional capacity and anxiety in high-risk group.

The effects of physiotherapy techniques in uncomplicated patients following CABG have been well-documented. In clinical practice, recommendations for exercise prescriptions and content of physiotherapy protocol may vary between medical centres and countries.

Renault et al.[13] concluded that physiotherapy techniques is too wide and there is no evidence about the superiority of one technique over the other. Therefore, using a specific protocol which consisted of some of these physiotherapeutic interventions is more suitable after heart surgery.

In our study, the incidence of PPC at least grade 2 is 20% in high-risk group and 18% in low-risk-group. Also, Johnson et al.[14] showed an incidence rate of 20%, similar to our results. Other studies reported lower incidence rates, such as those carried out by Stiller et al.[15] with an incidence rate of 7.1%, or Jenkins et al.[16] with an incidence rate of 10%. However, Dull and Dull[17] reported higher incidence rates, the incidence of PPC is 77% after heart surgery. These differences may be ascribable to various factors. The definition of PPC seems to be uncertain, though. In some studies, the definition of PPC is based only on chest radiographic changes, while others use a combination of variables for the definition. In our study, we used a scale which consisted of a combination of all variables and rated PPC.

In the literature data, physiotherapy interventions used to prevent PPC after CABG surgery have been questioned. Crowe and Bradley[18] reported that there was no addition of incentive spirometer to the physiotherapy protocol (deep breathing exercises, early mobilization and bronchial hygiene techniques). Jenkins et al.[16] compared the intervention group (incentive spirometer, deep breathing exercises coughing/huffing) with a control group (only early mobilization) and reported that there was no difference between the groups in recovery of pulmonary function or incidence of PPC. Herdy et al.[19] showed the effects of preoperative physiotherapy in minimizing possible adverse effects of cardiac surgery. Also, Yánez-Brage et al.[20] reported a lower number of pulmonary atelectasis in patients who had physiotherapy in the preoperative phase of CABG surgery. In a systematic review, Valkenet et al.[21] suggested a benefit of preoperative physiotherapy on PPC and length of hospitalization.

Furthermore, our results showed that physiotherapy make the patients with a high probability of PPC more resistant to the adverse effects of surgery and, consistent with the literature data, physiotherapy supported postoperative recovery after surgery. The patients with a high-risk for PPC had similar results such as patients with low-risk. As the length of stay in the hospital and ICU, the duration of intubation and days requiring a chest tube were similar in high-risk group, compared to the low-risk group.

In our physiotherapy protocol, we used deep breathing exercises, breathing exercises with incentive spirometer, thoracic expansion exercises at various levels and active cycle of breathing techniques. They produced an increase in the lung volume during the inspiration and collateral ventilation might result in increased alveolar ventilation, and thereby, reduced incidence of atelectasis. Also, using these exercises yielded a lower incidence of chest X-ray alterations, reduced atelectasis rates, pleural effusion, and pulmonary consolidation in both risk groups, which is also consistent with other study findings. In addition, it may be secondary to a lower incidence of pulmonary infections. Damaging and adverse effects of surgery on cough and bronchial hygiene are predisposing factors to the occurrence of lung infections. We used positioning and manual techniques such as percussion, vibration, and shaking for airway clearance, supported/assisted coughing and huffing in our physiotherapy protocol. Thus, no occurrence of lung infection was observed in high-risk group and in low-risk group in our study.

The 6MWT scores at the hospital discharge for both risk groups (444 m and 431 m, respectively) are consistent with the scores reported by Verrill et al.[22] ( mean 4 62 m ), ( 481 m m en, 4 40 m w omen, respectively). Hirschhorn et al.[23] reported 12.5% and 23.5% decline in the 6MWT distance one week after CABG surgery in the intervention and control groups, respectively. Similar to our results, the distance walked during 6MWT significantly decreased at discharge in all patients, although this decline was lower in highrisk group.

Baptista et al.[24] reported that CABG surgery improved the HRQoL scores in all patients; however, the improvement was greater in patients who walked less than 350 meters preoperatively. In our study, we did not find any difference in the HRQoL scores between the groups. It can be attributed to the fact that the 6MWT scores were higher than 350 meters in both groups.

Moreover, preoperative anxiety and depression symptoms are significantly associated with increased surgical mortality and morbidity rates in CABG patients.[25] Additionally, preoperative anxiety and postoperative depression increases postoperative re-admission rates more than two fold.[25] Garbossa et al.[25] reported the effects of preoperative and postoperative physiotherapy instructions on the anxiety of patients after CABG surgery. The lower levels of anxiety were observed in patients who were instructed and educated on physiotherapy and exercise in the preoperative period, compared to the control group. In our study, patients received information, were instructed, and educated on physiotherapy and breathing exercises preoperatively and both groups had reduced anxiety scores with a more prominent reduction in high-risk group. Several authors reported that prolonged duration of hospitalization increases stress and anxiety.[25] In our study, the length of hospital stay was relatively short; however, there was a decline in the anxiety scores in both risk groups.

In conclusion, this randomized, controlled trial demonstrated that physiotherapy helps patients in high-risk group for faster recovery after CABG. Physiotherapy is more critical in high-risk patients to obtain similar results, as in low-risk group. Therefore, screening patients to detect the presence of clinically significant risk factors may help to tailor a more effective physiotherapy program. In addition, our specific physiotherapy protocol is effective in both groups and better and applicable interventions are needed to treat and care for patients undergoing CABG surgery. Further investigations should be directed toward confirming our findings and expanding this area of research.

Declaration of conflicting interests
The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

Funding
The authors received no financial support for the research and/or authorship of this article.

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