CARDIOVASCULAR JOURNAL OF AFRICA • Volume 33, No 3, May/June 2022 154 AFRICA Methods This prospective observational study was conducted in the Department of Anesthesiology and Reanimation at the Prof Dr Cemil Taşçioğlu City Hospital from 1 May 2019 to 1 May 2020, after obtaining the permission of the ethics committee (date 16.04.2019, number 1249) and the written informed consent of the patients. A total of 100 patients with the American Society of Anesthesiologists physical status classification I–III, aged 18 years and over, undergoing open-heart surgery with sternotomy for coronary artery bypass grafting or valve replacement under general anaesthesia, were included in this study. For postoperative analgesia, 50 patients with PECS II block and 50 with PS block were consecutively enrolled in one of the groups at the end of the surgery and compared in terms of sedation scores, ventilation duration, pain scores at rest after extubation, which was our first endpoint, block duration and cumulative morphine consumption, which was our second endpoint, and complications such as itching, postoperative vomiting and nausea (POVN). Patient demographics were also recorded and compared. Patients with symptoms of congestive cardiac failure, allergy to local anaesthetics, haemodynamic instability, pre-existing infection at the block site, psychiatric disorders and those with prolonged ventilatory course in the intensive care unit were excluded from the study. All patients were pre-medicated with 0.06 mg/kg midazolam as part of the standard anaesthesia care in the study. General anaesthesia was induced after basic monitoring, including pulse oximetry, electrocardiograph, invasive blood pressure and bispectral index with intravenous administration of propofol (2 mg/kg), rocuronium (0.5–1 mg/kg), fentanyl (2 µg/kg) and remifentanil (0.01–0.2 μg/kg/min) in both groups. After tracheal intubation, maintenance of anaesthesia was done with propofol (2–4 μg/ml), rocuronium (0.5–1 mg/kg), remifentanil (2–4 ng/ml) and O2/air (FiO2 0.4). The depth of anaesthesia was set by the bispectral index score of 40 to 60 (range 0–100). The remifentanil infusion was titrated to maintain the patient’s blood pressure at around 20% of the baseline. The patients were transferred to the intensive care unit at the end of the surgery. All parameters were screened in the intensive care unit in the first, second, fourth, sixth, 12th and 24th hours. The block administration time in both groups was assumed as the beginning of the study in the postoperative period. All regional anaesthesia blocks were administered at the end of the surgery by the same anaesthesiologist under general anaesthesia and ultrasound guidance. The PS block was done with 2 ml of 0.25% bupivacaine injected into each parasternal space, 4 cm lateral to the sternal edge, deep to the major pectoral muscle and superficial to the intercostal muscle, bilaterally at the level between the second and sixth intercostal space with a total of 10 injections. The ultrasound-guided PECS II block was done with 20 ml 0.25% bupivacaine injected into each site. The local anaesthetic was injected between the serratus anterior and the pectoralis minor muscle (PECS II) over the third rib to block the anterior branches of the thoracic intercostal nerves at the level of T2 to T6, thoracodorsal nerve and long thoracic nerve. The pain scores were assessed with the visual analogue scale (VAS), where 0 means no pain and 10 means the worst pain ever. When the patient’s pain score was found to be three or more, intravenous bolus morphine at a dose of 2 mg was administered to the patients and noted. The sedation score was measured with the Richmond agitation–sedation scale (RASS).10 Statistical analysis The Number Cruncher Statistical System (NCSS) program (Kaysville, Utah, 2007, USA) was used for statistical analysis. Descriptive statistical methods (mean, standard deviation, median, frequency, percentage, minimum, maximum) were used when evaluating the study data. The normal distribution conformity of quantitative data was tested with Shapiro–Wilk testing and graphical examinations. Independent groups t-test was used to compare two groups of quantitative variables with normal distribution, and the Mann–Whitney U-test was used to compare two groups of quantitative variables that did not show a normal distribution. Pearson’s chi-squared test was used to compare qualitative data. Statistical significance was set at p < 0.05. Results The study was conducted with 100 patients divided into two groups (Fig. 1). The groups were compared for gender, age, body mass index (BMI), block and ventilation duration, postoperative pain scores at rest and cumulative morphine consumption. The block duration in the PS block group was statistically significantly higher than in the PECS II block group (p = 0.001, p < 0.05, respectively) (Table 1). There were no significant differences in age, gender, BMI and ventilation duration between the groups (p > 0.05) (Table 1). The VAS scores at rest in the fourth and sixth hours were statistically significantly higher in the PECS II block group than in the PS block group (p = 0.001, p = 0.001, p < 0.01, respectively) (Table 2). VAS scores at rest did not differ significantly between the groups (p > 00.05) in the first, second, 12th and 24th hours (Table 2). Cumulative morphine consumption in the PECS II block group was statistically significantly higher than in the PS block group in the fourth, sixth, 12th and 24th hours (p = 0.001, p = 0.001, p = 0.001, p = 0.001, p = 0.001, p < 0.01, respectively) (Table 3). Fifteen patients in the PECS II block group and six in the PS block group had POVN. PECS II 50% PS 50% Fig. 1. Distribution of patients between the groups.
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