This study was conducted at our university hospital from January 15, 2022, to October 15, 2022. The study included 46 subjects who underwent various surgical procedures, such as abdominal cholecystectomy, splenectomy, epigastric hernia repair, renal surgery, adrenal surgery, and laparoscopic surgery. The study was carried out after obtaining approval from the local ethical committee under code 9382 9/1/2022 (https://www.zu.edu.eg/). The review has a novel ID of NCT05587608 on ClinicalTrials.gov.
Inclusion criteria were (1) patients at risk, including older patients with declining physiological reserves, comorbidities, polypharmacy, cognitive disorders, and frailty; (2) patients aged 18 - 65 years; (3) patients scheduled for abdominal cholecystectomy; (4) patients who expressed unwillingness to undergo GA; (5) patients who were unable to undergo the standard SA technique in the lumbar area; and (6) patients who were unable to tolerate the traditional method of SA.
Exclusion criteria were preexisting neurological illnesses (multiple sclerosis and other demyelinating illnesses), sepsis, severe hypovolemia, and coagulopathy. Also, patients with local infection at the site of the operation, increased intracranial pressure, left ventricular outflow blockage, and significant mitral and aortic stenosis with symptoms of hypertrophic obstructive cardiomyopathy were excluded.
Demographic data regarding age, sex, type of operation, duration of operation, body mass index (BMI), and score of the American Society of Anesthesia (ASA) were recorded. At the time of examination, basic investigations were conducted, and the patient's written, fully informed consent was obtained before proceeding with any further steps or procedures. Prior to the induction of anesthesia, several monitoring devices were set up, including an electrocardiogram (ECG) machine, automatic non-invasive blood pressure measurement equipment, and a pulse oximeter.
Randomization in this study was conducted using a method involving serially numbered, opaque envelopes that concealed the randomization assignments generated by a computer-generated list. Patients were divided into 2 equal groups: Group 1 (n = 23) received standard GA, and group 2 (n = 23) received thoracic segmental SA. A combination of 10 mg of hyperbaric bupivacaine 0.5% and 25 μg of fentanyl was injected through the spinal needle. The epidural catheter was then threaded through the Tuohy needle after withdrawal of the spinal needle to keep only 4 cm up in the epidural space.
3.1. Technique of General Anesthesia
All patients in group 1 were ventilated with oxygen via a face mask, followed by laryngoscopy and tracheal intubation. The anesthesia was induced using 2.5 mg/kg of propofol, 2 μg/kg of fentanyl, 0.8 mg/kg of cisatracurium, and 1.5 mg/kg of lidocaine. Following intubation, the respiratory rate (RR) was changed to keep the end-tidal CO2 (EtCO2) between 33 and 36 mm Hg while maintaining a tidal volume of 8 mL/kg and positive end-expiratory pressure (PEEP) of 5 cm H2O. Sevoflurane (1% - 1.5%), muscle relaxant doses, and regulated mechanical breathing were used to accomplish maintenance. A gas analyzer was used to measure EtCO2 and sevoflurane continually. Following the surgery, 2 mg of neostigmine and 1 mg of atropine were administered to treat any remaining neuromuscular blockade.
Electrocardiogram, pulse rate, arterial blood pressure, respiration rate, pulse oximetry, and EtCO2 were continually measured during the procedure. All information was captured every 5 min.
3.2. Technique of Thoracic Segmental Spinal Epidural Anesthesia
Group 2 was given ultrasound-guided thoracic segmental SA at the level of T9 - 10 interlaminar space; patients were in a sitting position. We used a combined spinal epidural tray (PERIFIX B Braun, Melsungen, Hessen Germany)
®. The epidural needle was 17 Ga Touhy, while Pencil- the Point Spinal Needle was 27 Ga (
Figure 1A and
B).
A and B, Technique of US guided segmental thoracic neuro-axial block (VD, ventral dura; DD, dorsal dura; L, lamina; N, needle).
In this group, we used a SonoSite C60x/5-2 MHz M-Turbo Convex Probe Ultrasound Transducer to identify the T10 interlaminar space, and after complete sterilization, we introduced the epidural needle in a paramedian in plan approach till the epidural space. The spinal needle was then introduced through the epidural needle not more than 0.5 cm beyond the dura mater. A combination of 2 mL of hyperbaric bupivacaine 0.5% and 25 ug of fentanyl was injected through the spinal needle. The epidural catheter was then threaded through the Tuohy needle after withdrawal of the spinal needle to keep only 4 cm up in the epidural space.
After testing the sensory level using a piece of ice and the motor level using a modified Bromage scale while the patient was in a supine position, surgery was started after achieving sufficient surgical anesthesia. At the same time, continuous infusion of isobaric bupivacaine in the epidural catheter started at a rate of 2 mL/h. During surgery, we gave drugs needed to treat anxiety, pain, hypotension, bradycardia, pruritis, nausea, and vomiting. Perioperative monitoring for hemodynamics, pain, anxiety, nausea, vomiting, and neurological symptoms were recorded, and all patients were followed up during their hospital stay and for 72 hours postoperative. If they were discharged, they would be followed up using a phone call.
Postoperatively, both groups: Pain was treated with IV morphine by patient controlled analgesia (PCA), PCA settings were; 1 mg morphine/mL, no background infusion, bolus dose 2 mL and lockout interval 15 min. Pain was monitored using the Visual Analog Scale (VAS) at rest and during cough every 4 h for 24 h. Hemodynamic parameters (including heart rate [HR], mean arterial pressure [MAP], and RR) were also monitored every 2 h for 24 h. Total opioid consumption by PCA was documented. Any negative side effects were noted, including bradycardia, hypotension, nausea, vomiting, urinary incontinence, and stomach pain. The total amount of opioids consumed and the first analgesic request were noticed and recorded. Patient satisfaction using Short Assessment of Patient Satisfaction (SAPS) and surgeon satisfaction based on a Likert scale were documented.
Each participant involved in the research study provided written informed consent, which was obtained after the project received approval from the university's ethics committee. According to the Declaration of Helsinki, each participant in the research provided written informed permission, which was obtained after the project was given the green light by the university's ethics committee.
The data were analyzed using SPSS version 24. The statistical significance was assessed using the analysis of variance (ANOVA) test, multiple linear regression, standard seaborn, Matplotlib boxplots, Wilcoxon's tests, and Spearman's correlation. Each variable was evaluated in accordance with the sort of data it held (parametric or not). P values less than 0.05 were deemed statistically significant findings.