The aim of this randomized controlled study was to investigate the effect of injecting local anesthetic agents into the sternotomy incision site and around the drains on the amount of opioids used in the postoperative period and the healing process. The main questions it aims to answer are:

• In patients undergoing open heart surgery, does the application of local anesthetic around the sternotomy incision site and chest tube(s) reduce the amount of postoperative opioid use?
• In patients undergoing open heart surgery, does the application of local anesthetic around the sternotomy incision site and chest tube(s) accelerate postoperative recovery?

In this study, LIDOFAST 40 mg/2 ml + 0.025 mg/2 ml will be injected into the sternotomy incision area and around the drains of the patients in the experimental group, and the amount of opioid consumed in the postoperative period will be recorded and the healing process will be observed.

After open heart surgery, patients experience high levels of pain at the sternotomy incision site and around the chest tube(s), affecting their recovery. This study was conducted to determine the effects of local anesthetic application around the sternotomy incision site and chest tube(s) on the amount of opioids used and recovery after surgery in patients undergoing open heart surgery. The study population consisted of patients who underwent open heart surgery in the Cardiovascular Surgery Intensive Care Unit of a hospital. The sample group consisted of patients who met the inclusion criteria (patients between 18 and 65 years of age, conscious, and willing to communicate and cooperate after open heart surgery). For the planned study, the "G. Power-3.1.9.2" program was used to calculate the sample size at an 80% confidence level prior to data collection. The sample was determined with the "Sample Calculation Formula (n=Nz2pq / d2(N-1) + z2pq). According to the literature review, it was determined that the "effect size value was 0.096". Accordingly, with a primary type error of 5% (Z = 1.96), a test power of 80%, and an effect size of 0.096 units, the minimum sample size was calculated as n = 60. Thus, of the 60 volunteer patients included in the study, 30 were randomly assigned to the experimental group and 30 to the control group. Data were collected using a Descriptive Characteristics Form and the Postoperative Recovery Index (PoRI).

A total of 2 ampoules of LIDOFAST 40 mg/2 ml + 0.025 mg/2 ml were injected into the sternotomy incision site and around the chest tubes of 30 patients in the experimental group. The total number and dose of opioids, the total number and dose of analgesics used to relieve the pain of the patients in the 24 hours after the injection of 2 ampules of LIDOFAST 40 mg/2 ml + 0.025 mg/2 ml, and the total number and dose of analgesics were recorded, and the patients were interviewed face-to-face 24 hours later, and PoRI was recorded. No intervention was performed on 30 patients in the control group, and standard treatment and care continued to be applied to these patients. SPSS 19.0 (SPSS Inc., Chicago, Illinois, USA) package program was used for data evaluation. Descriptive statistics for continuous variables were expressed as mean and standard deviation, while descriptive statistics for categorical variables were expressed as number and percentage. Normality of data distribution was tested by Kolmogorov-Smirnov, and homogeneity of variances was tested by Levene's test. In independent two-group comparisons in terms of continuous variables, the Independent Groups T-test was used in cases where normal distribution conditions were met, and Mann-Whitney U test statistics were used in cases where normal distribution conditions were not met. In independent comparisons of more than two groups in terms of continuous variables, one-way analysis of variance (ANOVA) was used in cases where normal distribution conditions were met, and Kruskal-Wallis test statistics were used in cases where normal distribution conditions were not met. The Spearman rank correlation coefficient was calculated between groups to determine the relationship between continuous variables. All test data were evaluated at a 95% confidence interval and a 0.05 significance level.

Research Hypotheses

H0: In patients undergoing open heart surgery, local anesthetic application around the sternotomy incision site and chest tube(s) has no effect on the amount of postoperative opioid use and recovery.

H1: In patients undergoing open heart surgery, local anesthetic application around the sternotomy incision site and chest tube(s) has an effect on the amount of postoperative opioid use and recovery.

Inclusion Criteria:

• patients between 18 and 65 years of age, and willing to communicate and cooperate after open heart surgery

Exclusion Criteria:

• Patients younger than 18 years and older than 65 years, unwilling to communicate and cooperate, sensitive to local anaesthetics and not willing to participate in the study

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.