Open-heart surgery is currently performed in many countries to increase the survival and quality of life of patients with cardiac diseases [
Several factors contribute to the pain following open-heart surgery, including sternotomy, harvesting saphenous vein, harvesting internal thoracic artery, and inserting various drains [
According to medical personnel, patients are not in great pain after sternotomy because the tissue damage that occurred is negligible and the patients are minimally mobile after surgery. Nevertheless, Lahtinen reported moderate-to-severe pain (pain score of 4 to 10) in up to 75% of the patients in the first 48 hours after cardiac surgery [
A variety of medicinal and nonmedicinal therapies have been proposed for pain management. Medicinal methods such as opioids are currently used to alleviate pain in cardiac patients but are not desirable as the first line of treatment because of their costs and adverse effects on different body parts, which increase patient mortality and morbidity [
Studies indicate that distraction is an effective nursing intervention for controlling short-term and transient pain by increasing endorphins [
RB is one of the distraction methods that make patients voluntarily distract themselves from a painful stimulus and thus help control their pain [
Several studies have reported the effect of RB on reducing pain [
Sternotomy site pain is the patients’ most common complaint and probably the most severe postoperative pain experienced, which can be associated with increased patient morbidity and mortality [
This parallel randomized, controlled nonmasked clinical trial was conducted between September 2018 and September 2019 on patients undergoing CABG surgery at Kowsar Hospital, affiliated to Semnan University of Medical Sciences in Iran. Following a preliminary study with ten patients from each group (RB and control), the mean and standard deviation of the severity of pain were found as 1.3 ± 0.65 in the RB group and 2 ± 0.8 in the control group. Then, taking into account 95% confidence interval and 80% test power and using equation (
CONSORT flowchart of the study.
The study inclusion criteria were as follows: undergoing elective CABG surgery, age 35–80 years, stable hemodynamic status (blood pressure>90 mmHg, and 50 < pulse rate < 110), no previous history of CABG, no life-threatening arrhythmias, and no use of Cardiopulmonary Bypass (CPB). The exclusion criteria were as follows: having a history of diabetes, prolonged intubation (more than 24 hours after surgery), dependence on inotropic agents for hemodynamic stability after extubation, PaO2 < 60 mmHg without receiving oxygen via the nasal cannula or mask, renal dysfunction before and after surgery, history of chronic pain, and the need for other pain control methods such as music or massage therapy.
In terms of ethical considerations, the Ethics Committee of Semnan University of Medical Sciences approved the present research (IR.SEMUMS.REC.1397.138). This study was also registered in the Iranian Registry of Clinical Trials (IRCT20120109008665N7). After introducing himself to the patients, the researcher briefed the participants on the research objectives and procedures, assured them of the confidentiality of their information and their right to withdraw from the study at their own discretion and responded to their questions. The subjects then signed written informed consent forms for participation.
RB technique was performed for the intervention group. RB was individually taught to the intervention group before surgery until they could perform it independently and correctly. The day after surgery, upon gaining full consciousness and hemodynamic stability, the patients were asked to close their eyes in the supine position, inhale through the nose, then hold their breath, and exhale through the mouth, while counting from 1 to 3 in each step. All the patients in the intervention group were trained to focus only on air entry and exit while breathing, and they were asked to perform RB once every five minutes, lasting one minute each time, for 20 minutes (totally four times every 20 minutes) [
Data were collected using a two-part questionnaire. The first part dealt with the patients’ demographic details, including age, gender, education, body mass index (BMI), underlying diseases, duration of hospitalization before and after surgery, history of smoking and opioid use, amount of opioid injection, on-pump duration, ejection fraction, duration of mechanical ventilation, and the number of grafts and chest tubes. Surgery was performed using a cardiopulmonary pump in both groups. Also, the method of anesthesia, anesthesia medications, and fluid therapy during and after surgery were the same for all the patients. Any changes in routine instructions were recorded by the researcher.
In the second part, the patients’ pain score data were collected by the Visual Analog Scale (VAS). Pain was measured at 9 a.m. and 9 p.m. before and after RB performance in both groups for three days. The patients were asked to express their pain severity by choosing a number between 0 (no pain) and 10 (most severe pain). VAS categorizes the severity of pain into four groups: 0 = no pain, 1–3 = mild pain, 4–7 = moderate pain, and 8–10 = severe pain. In one study, Alghadir et al. confirmed the reliability of VAS with an intraclass correlation coefficient of 0.97 [
Data were analyzed with a per-protocol approach in SPSS-19 (SPSS Inc., Chicago, IL, USA) at a significance level of 0.05. The study data were described, grouped, and compared in absolute and relative frequency tables. The results of the Kolmogorov–Smirnov test confirmed the normal distribution of the data. The independent sample
For analysis of variance with repeated measures, the following statistical presuppositions were examined first: quantitativeness of the dependent variable, elimination of outliers, normal distribution of the dependent variable distribution, and confirmation of sphericity of the groups with Mauchly’s statistics, and three factors of intervention (versus control), time point during the day (difference between before and after scores at 9 a.m. and 9 p.m.), and days (first, second, and third) were entered into the analysis.
The present study recruited 60 patients after CABG surgery. The patients’ mean age was 61.58 ± 9.7 years, and the majority (80%) were male. Table
The demographic and surgical-related characteristics of the participants in the rhythmic breathing/control groups.
Groups characteristics | RB ( | Control ( | |
---|---|---|---|
Male | 24 (80) | 27 (90) | |
Female | 6 (20) | 3 (10) | |
Below high school diploma | 28 (93.3) | 28 (93.3) | |
Higher education | 2 (6.7) | 2 (6.7) | |
Yes | 9 (30) | 15 (50) | |
No | 21 (70) | 15 (50) | |
Yes | 24 (80) | 28 (93.3) | |
No | 6 (20) | 2 (6.7) | |
2 | 1 (3.3) | 1 (3.3) | |
3 | 10 (33.3) | 9 (30) | |
≥4 | 19 (63.4) | 20 (66.7) | |
2 | 24 (80) | 27 (90) | |
3 | 6 (20) | 3 (10) | |
(Mean ± SD) | (Mean ± SD) | ||
Age (years) | 60.80 ± 9.4 | 62.37 ± 10.1 | |
BMI (kg/m2) | 26.73 ± 4.4 | 26.03 ± 4.1 | |
Smoking (butts/day) | 4.73 ± 10.9 | 9.83 ± 15.3 | |
On-pump duration (minute) | 109.70 ± 25.3 | 111.90 ± 28 | |
Ejection fraction (%) | 46.50 ± 11.2 | 50.83 ± 5.5 | |
Medical ventilation time (hour) | 9.63 ± 4.2 | 10.93 ± 4.3 | |
Duration of preoperative hospitalization (day) | 4.5 ± 2 | 5.53 ± 3.2 | |
Duration of postoperative hospitalization (day) | 5.67 ± 1.4 | 6.03 ± 1.3 |
RB: rhythmic breathing; BMI: body mass index;
The independent
The comparisons of mean scores of the pain severity in the RB and control groups.
Day | Hours | Measurement times | Groups | Mean ± SD | Min | Max | value |
---|---|---|---|---|---|---|---|
Fist day | 9 a.m. | Before intervention | RB | 2.37 ± 0.99 | 1 | 5 | |
Control | 2.30 ± 1.39 | 1 | 6 | ||||
After intervention | RB | 1.07 ± 0.64 | 0 | 3 | |||
Control | 1.50 ± 0.5 | 1 | 2 | ||||
9 p.m. | Before intervention | RB | 2.10 ± 0.84 | 1 | 4 | ||
Control | 1.90 ± 0.84 | 1 | 4 | ||||
After intervention | RB | 0.87 ± 0.50 | 0 | 2 | |||
Control | 1.53 ± 0.57 | 1 | 3 | ||||
Second day | 9 a.m. | Before intervention | RB | 1.90 ± 0.54 | 1 | 3 | |
Control | 2 ± 1.23 | 1 | 5 | ||||
After intervention | RB | 0.83 ± 0.46 | 0 | 2 | |||
Control | 1.57 ± 0.62 | 1 | 3 | ||||
9 p.m. | Before intervention | RB | 1.97 ± 0.49 | 1 | 3 | ||
Control | 1.73 ± 0.64 | 1 | 3 | ||||
After intervention | RB | 0.97 ± 0.49 | 0 | 2 | |||
Control | 1.67 ± 0.60 | 1 | 3 | ||||
Third day | 9 a.m. | Before intervention | RB | 1.73 ± 0.58 | 1 | 3 | |
Control | 1.47 ± 0.57 | 1 | 3 | ||||
After intervention | RB | 0.70 ± 0.53 | 0 | 2 | |||
Control | 1.43 ± 0.50 | 1 | 2 | ||||
9 p.m. | Before intervention | RB | 1.77 ± 0.62 | 1 | 3 | ||
Control | 1.43 ± 0.50 | 1 | 2 | ||||
After intervention | RB | 0.70 ± 0.53 | 0 | 2 | |||
Control | 1.43 ± 0.50 | 1 | 2 |
RB : rhythmic breathing; SD: standard deviation; Min : minimum; Max : maximum;
Mean scores of the pain severity after CABG.
The comparison of the patients in the RB and control groups in terms of pain severity.
Day | Hours | Measurement times | Groups | No pain | Mild pain | Moderate pain | |
---|---|---|---|---|---|---|---|
Fist day | 9 a.m. | Before intervention | RB | 0 | 25 | 5 | |
Control | 0 | 24 | 6 | ||||
After intervention | RB | 4 | 26 | 0 | |||
Control | 0 | 30 | 0 | ||||
9 p.m. | Before intervention | RB | 0 | 27 | 3 | ||
Control | 0 | 29 | 1 | ||||
After intervention | RB | 6 | 24 | 0 | |||
Control | 0 | 30 | 0 | ||||
Second day | 9 a.m. | Before intervention | RB | 0 | 30 | 0 | |
Control | 0 | 25 | 5 | ||||
After intervention | RB | 6 | 24 | 0 | |||
Control | 0 | 30 | 0 | ||||
9 p.m. | Before intervention | RB | 0 | 30 | 0 | — | |
Control | 0 | 30 | 0 | ||||
After intervention | RB | 4 | 26 | 0 | |||
Control | 0 | 30 | 0 | ||||
Third day | 9 a.m. | Before intervention | RB | 0 | 30 | 0 | — |
Control | 0 | 30 | 0 | ||||
After intervention | RB | 10 | 20 | 0 | |||
Control | 0 | 30 | 0 | ||||
9 p.m. | Before intervention | RB | 0 | 30 | 0 | — | |
Control | 0 | 30 | 0 | ||||
After intervention | RB | 10 | 20 | 0 | |||
Control | 0 | 30 | 0 |
RB: rhythmic breathing;
The comparison of mean differences scores of the pain severity before and after intervention in the RB and control groups.
Day | Measurement times | Groups | Mean ± SD | Min | Max | |
---|---|---|---|---|---|---|
Fist day | 9 a.m. | RB | 1.3 ± 0.59 | 1 | 3 | |
Control | 0.8 ± 1.06 | 0 | 4 | |||
9 p.m. | RB | 1.23 ± 0.56 | 1 | 3 | ||
Control | 0.36 ± 0.61 | 0 | 2 | |||
Second day | 9 a.m. | RB | 1.06 ± 0.25 | 1 | 2 | |
Control | 0.43 ± 0.97 | 0 | 3 | |||
9 p.m. | RB | 1/0 ± 0.0 | 1 | 1 | ||
Control | 0.06 ± 0.25 | 0 | 1 | |||
Third day | 9 a.m. | RB | 1.03 ± 0.18 | 1 | 2 | |
Control | 0.03 ± 0.18 | 0 | 1 | |||
9 p.m. | RB | 1.06 ± 0.25 | 1 | 2 | ||
Control | 0.0 ± 0.0 | 0 | 0 |
RB : rhythmic breathing; SD: standard deviation; Min : minimum; Max : maximum;
Results of repeated-measures ANOVA in terms of pain severity in the RB and control groups.
Source of change | Variables | Sum of squares | df | Mean squares | F | |
---|---|---|---|---|---|---|
Within-subjects | Timea | 13.10 | 1 | 13.10 | 10.56 | 0.002 |
Time × group | 3.66 | 1 | 3.66 | 2.95 | 0.09 | |
Error | 71.90 | 58 | 1.24 | |||
Between-subject | Constant | 176.4 | 1 | 176.4 | 387.05 | <0.001 |
Group | 62.50 | 1 | 62.50 | 137.13 | <0.001 | |
Error | 26.43 | 58 | 0.456 |
The present findings on the effect of RB on post-CABG sternotomy pain control confirmed that RB was effective in reducing the severity of sternotomy pain after surgery in the intervention group. To the best of the authors’ knowledge, this is the first study to investigate the effect of RB on post-CABG sternotomy pain.
After the intervention, the severity of pain, as measured on both occasions (9 a.m. and 9 p.m.) in three consecutive days following the surgery, was significantly lower in the intervention group compared to the controls. The results of the repeated-measures ANOVA showed a significant difference between the two groups in the mean difference in the severity of pain over the three days, which was lower in the intervention group. In agreement with this result, several studies conducted on the effect of RB on pain have also shown that RB can help reduce pain and the number of analgesics administered after surgery [
Nevertheless, the results obtained by Slade showed that these techniques are less effective than expected in reducing pain [
The results showed no significant difference between the two groups in the dose of morphine administered (1.97 mg in the RB group and 2.57 mg in the control group), but this difference was clinically significant. Other studies reported a significant difference between their intervention and control groups in the number of analgesics received after surgery [
In the present study, the severity of pain was significantly higher in the RB group than the control group at 9 p.m., three days before the intervention, but after the intervention, a significant reduction was observed in the severity of pain in the RB group compared to the controls. This important finding is indicative of the effect of RB on reducing pain, which was also confirmed by the repeated-measures ANOVA results.
The results of pain intensity in patients in both groups also revealed that the pain intensity in the RB group significantly decreased after the intervention compared to that in the control group at 9 a.m. and 9 p.m. for three consecutive days. According to the results, although the effect of time on reducing patients' pain intensity should not be ignored, the intervention (RB) significantly affected patients’ pain intensity.
According to the researchers, it is necessary to consider factors affecting the perception of the severity of pain. The nature and severity of postoperative pain depend on the size and amount of incision and type of surgery. In addition, the perception of pain depends on ethnicity, culture, beliefs, personal experience of pain, and personality [
The main limitation of the present research included the reluctance of the patients to follow the instructions provided for performing the breathing exercises owing to their improper psychological status. Some measures were thus taken to encourage them to cooperate. A natural limitation of the present study was also associated with the subjective nature of pain, which caused differences in the degree of pain reported by different individuals because pain severity is a patient-reported outcome. The unicenter type of this study and its small sample constituted other limitations, which restricts the external validity of the findings and prohibits their generalizability to other centers. It is recommended that further research be performed with larger samples and more prolonged follow-ups to obtain more accurate results on the effects of rhythmic breathing on pain after CABG with sternotomy.
The results confirmed that RB is effective in reducing the severity of sternotomy pain after CABG surgery. Given the importance of the management of pain as the fifth vital sign and to prevent the side-effects and problems caused by the lack of proper pain control, especially in patients after CABG, RB can be recommended as a simple, safe, and inexpensive method in the form of an independent nursing activity in conjunction with other medical measures for reducing the severity of pain in patients after CABG surgery.
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
This study was approved by the Ethics Committee of Semnan University of Medical Sciences (approval code: IR.SEMUMS.REC.1397.138).
Informed written consent was obtained from each participant.
All the authors have read and approved the final manuscript.
The authors declare that there are no conflicts of interest regarding the publication of this paper.
HB, MK, and AE contributed to the conception and design of the study and the study protocol. MK and HB managed the running of the study. HB and AE conducted data analysis and all authors helped with data interpretation. MK and HB wrote this manuscript. All authors read and approved the final version of the manuscript.
The present study was extracted from a master thesis on critical care nursing at Semnan University of Medical Sciences and approved as a research project by the university (Code: 1455). The authors would like to express their sincere gratitude to the health center authorities, including Dr. Ghods, and all the university authorities for their financial support and the permission they granted to perform this study. Semnan University of Medical Sciences supported this study with a postgraduate grant (no. 1455).