1. Introduction

The implementation of the concept of accelerated recovery aims to achieve both rapid and high-quality recovery after cardiac surgery [1]. Since these goals may contradict high-dose opioid administration, perioperative pain relief protocols should include alternative pain relief methods or opioid adjuvants [2]. Recent scientific studies have been devoted to the development and implementation of a multimodal concept of pain relief, which aims to reduce opioid consumption and actively introduce regional pain relief methods into postoperative pain relief practice [3-4].

Today, there is an urgent need to develop a strategy to reduce perioperative opioid use in cardiac surgery while ensuring efficient postoperative analgesia for patients after cardiac surgery. This is facilitated by the introduction of regional pain relief methods under ultrasound guided navigation [5-6]. One of the new approaches to treating postoperative pain syndrome in cardiac surgery is deep parasternal block under ultrasound guided navigation. A review of recent literature has revealed that studies aimed at investigating the efficiency and safety of parasternal block after coronary artery bypass grafting were based on the study of hemodynamic parameters, stress hormones, clinical laboratory data and certain factors of clinical outcome of the disease [7-8]. Studying the impact of parasternal block after coronary artery bypass grafting surgery in the early postoperative period on clinical outcomes is currently a relevant issue requiring scientific research in this area.

The aim of the study was to evaluate the impact of deep parasternal block after coronary artery bypass grafting surgery on clinical outcomes in the early postoperative period.

2. Material and Methods

The study included 121 patients who underwent off-pump coronary artery bypass grafting at the Republican Research Center of Emergency Medicine and its Bukhara branch between 2022 and 2024. Patients were divided into two groups depending on the method of postoperative pain relief. The first group (main group) included 60 patients. The mean age of patients was 62.48 ± 9.00 years. There were 45 (75%) men and 15 (25%) women. Postoperative pain relief was provided as follows: immediately after the surgery, patients received a deep parasternal block on both sides under ultrasound navigation control. Narcotic analgesics were used as a “rescue strategy” when needed. The second group (control group) consisted of 61 patients. The mean age was 61.95 ± 7.41 years. There were 44 (72.1%) men and 17 (27.9%) women. Postoperative pain relief was provided using narcotic analgesics (morphine, promedol) in combination with NSAIDs and paracetamol at a dose of 1000 mg. All patients were diagnosed with ischemic heart disease of varying severity. Among concomitant pathologies, chronic obstructive pulmonary disease was detected in 20.7% of cases, diabetes mellitus of various stages - in 29.7% of cases, and obesity of varying severity - in 19.8% of cases.

The following indicators were recorded in the postoperative period:

• time of first analgesic requirement;

• extubation time;

• time of gastrointestinal motility recovery;

• presence of postoperative nausea and vomiting;

• amount of narcotic analgesic used in the postoperative period;

• duration of stay in the intensive care unit;

• duration of hospital stay.

Statistical analysis was performed using StatTech v. 4.8.3 (developed by StatTech LLC, Russia). Pearson's chi-square test and Welch's t-test were used to evaluate the statistical significance of the results.

3. Results

Against the background of a decrease in the use of parasternal blocks as part of a multimodal analgesia regimen, there was a 95% reduction in the consumption of narcotic analgesics (NA) in the main group of patients compared to the control group. A reduction in the consumption of narcotic analgesics led to improved treatment outcomes in the postoperative period, which were also manifested by a reduction in the extubation time of patients in the main group by 37.3%. A correlation analysis of the relationship between the total consumption of narcotic analgesics and the time of extubation revealed a significant direct correlation (Table 1).

Table 1. Results of correlation analysis of the relationship between total NA consumption and extubation time

When the total NA consumption increases by 1 mg, the extubation time is expected to increase by 9.731 minutes. The resulting model explains 33.5% of the observed dispersion in extubation time.

An analysis of postoperative nausea and vomiting (PONV) revealed that PONV was observed in 43.3% of patients in the main group, while the absence of PONV was noted in 56.7% of cases. PONV was detected in 75.4% of patients in the control group. When analyzing the presence of PONV depending on the group, we found statistically significant differences (p<0.001), i.e., PONV was observed in the control group twice as often as in the main group (method used: Pearson's chi-square test).

The relationship between the development of PONV and the amount of narcotic analgesic consumed was analyzed. When NA was administered at a dose of 9.58 ± 8.46 mg, the chances of developing PONV were higher in 59.5% (n=72 of the total number of patients). The use of NA at a dose of less than 3.37 ± 5.24 mg contributed to the absence of PONV in 49 patients (from the total number of patients), which amounted to 40.5%. So, the more NA was used for postoperative pain relief, the more often PONV happened. The above data revealed statistically significant differences (p < 0.001) (method used: Welch's t-test) (Table 2).

Table 2. The correlation between PONV development and NA dose

Against the backdrop of increased consumption of narcotic analgesics for postoperative pain relief in the control group, abdominal distension was observed 2.1 times more often than in the main group of patients. In the control group, this phenomenon was observed in 46 (75.4%) cases, while in the main group, abdominal distension was observed in 22 (36.7%) patients. Based on the data obtained, statistically significant differences were observed (p<0.001) (method used: Pearson's chi-square test). The probability of developing abdominal distension in the control group was 5.297 times higher than in the main group, and the differences in probability were statistically significant (95% CI: 2.417–11.606).

We analyzed the development of abdominal distension from the total NA consumption. As the consumption of narcotic analgesics increased, the probability of developing abdominal distension increased. The minimum dose of narcotic analgesic leading to the development of abdominal distension was 9.85 ± 8.01 mg (Table 3).

Table 3. Analysis of abdominal distension development depending on total NA consumption

Analysis of total NA consumption depending on abdominal distension revealed statistically significant differences (p<0.001) (method used: Welch's t-test).

We conducted a comparative analysis of the time required for intestinal peristalsis recovery between the groups. The time of intestinal peristalsis recovery in the main group was 6.13 ± 1.17 hours (95% CI 5.83 – 6.44), which was 45.5% earlier than in patients of the control group, where this indicator made up 11.26 ± 2.57 hours (95% CI 10.60 – 11.92). According to the data obtained when comparing the time of peristalsis recovery depending on the group, we found statistically significant differences (p<0.001) (method used: Welch's t-test).

A correlation analysis of the relationship between total NA consumption and peristalsis recovery time was also performed.

An extension of the recovery time of peristalsis by 0.318 hours should be expected with an increase of the total consumption of 1 mg. The resulting model explains 59.8% of the observed variance in peristaltic recovery time (Table 4).

Table 4. Results of the correlation analysis of the relationship between the total NA consumption and peristaltic recovery time

An analysis of ICU duration stay compared between the groups revealed a significantly significant difference. The duration of ICU stay in the main group of patients was 2.13 ± 0.68 days (95% CI 1.96 – 2.31), and in the control group this value made up 4.97 ± 1.97 days (95% CI 4.46 – 5.47), which was significantly longer by 57.1%. The duration of hospital stay of patients in the control group was 12.85 ± 4.48 days (95% CI 11.71 – 14.00), and in the main group - 10.33 ± 1.68 days (95% CI 9.90 – 10.77), which was significantly lower by 24.3% compared with patients in the control group.

According to the above data, a reliable decrease in the total treatment cost of patients in the main group by 47.5% was noted due to a decrease in the duration of patients’ stay in the ICU and hospital in the early postoperative period. This was demonstrated by the reliably significant economic efficiency of the proposed method of postoperative pain relief for patients after coronary artery bypass grafting surgery.

4. Conclusions

The use of deep parasternal block under ultrasound navigation control as a basic method of pain relief after coronary artery bypass grafting surgery has a beneficial effect on clinical results of the study.

This method contributed to a 95% reduction in the consumption of narcotic analgesics in patients in the main group compared to patients in the control group; reduction in extubation time for patients in the main group by 37.3%; reduction in the incidence of postoperative nausea and vomiting by 43.4%; reduction of abdominal distension episodes by 2.1 times; reduction of intestinal peristalsis recovery time by 45.5%.

Conflict of Interests’ Statement

The authors declare no conflict of interest.

This study does not include the involvement of any budgetary, grant or other funds.

The article is published for the first time and is part of a scientific work.

ACKNOWLEDGEMENTS

The authors express their gratitude to the management of the multidisciplinary clinic of Republican Research Center of Emergency Medicine (RRCEM) and its Bukhara branch for the material provided for our study.

Source of Funding

Each of the authors has reviewed and approved this manuscript. None of the authors has a conflict of interest, financial or otherwise. This manuscript is original, no part of it has been previously published and is not being considered for publication elsewhere. The corresponding author agrees to accept full responsibility for authorship at the submission and review stages of the manuscript.

Ethical Aspects

The study was approved by the local ethics committee of the Republican Research Center of Emergency Medicine (RRCEM). All patients signed voluntary informed consent to participate. Personal data were encrypted and used only for scientific purposes.