General anaesthesia (GA) has evolved since ancient times with continuous advancements aimed at improving patient safety and perioperative outcomes. Effective airway management is a fundamental component of GA, ensuring adequate oxygenation and ventilation during surgery.¹ Although modern anaesthesia is considered safe and indispensable, it is still associated with several postoperative complications. Increasing emphasis on quality assurance in anaesthesia practice has highlighted the need to reduce postoperative morbidity and enhance patient satisfaction.² Consequently, attention has focused on minimizing postoperative pharyngolaryngeal complications such as postoperative nausea and vomiting (PONV), postoperative sore throat (POST), postoperative cough (POC), and postoperative hoarseness of voice (POHV).3 Tracheal intubation is the primary cause of airway mucosal trauma in patients undergoing surgery under general anaesthesia. Postoperative sore throat is a common and distressing consequence, leading to significant discomfort in the postoperative period.4The incidence of POST ranges from 21% to 65% following endotracheal intubation.5 Despite multiple preventive measures, POST has not been completely eradicated.6 The proposed mechanisms include mucosal erosion, inflammation, and dehydration of the airway, resulting in tracheal irritation. Although considered a minor complication, POST contributes to patient dissatisfaction and may prolong hospital stay.7,8 Several factors influence the incidence of postoperative sore throat, including smoking, snoring, difficult intubation, female sex, duration of anaesthesia, patient positioning, and the use of succinylcholine. Procedural factors such as endotracheal tube size, cuff pressure, repeated intubation attempts, duration of intubation, and type of surgery also play a significant role.9 Both pharmacological and non-pharmacological strategies have been employed to reduce POST, with no single modality proving completely effective. Non-pharmacological measures include careful airway manipulation, use of smaller endotracheal tubes, and minimization of intracuff pressure. Pharmacological approaches such as gargling or nebulization with agents like lignocaine and magnesium sulphate have gained attention due to their safety and ease of administration.10 Lignocaine reduces airway reflexes through its analgesic and anti-inflammatory properties, while magnesium sulphate, an NMDA receptor antagonist, modulates nociception and inflammation. However, limited studies have directly compared these agents.11 Therefore, the present study was undertaken to evaluate and compare nebulized lignocaine and magnesium sulphate in reducing postoperative pharyngolaryngeal complications.

This prospective, randomized, controlled, triple-blind study was conducted in the Department of Anaesthesiology, Dr. Rajendra Prasad Government Medical College (RPGMC), Kangra at Tanda, Himachal Pradesh. The study was registered with the Clinical Trial Registry of India (CTRI/2024/02/062836) and was carried out after approval from the Institutional Protocol Review Committee. The study duration was 12 months, including data collection, organization, analysis, and interpretation. Study Population Ninety patients of either sex, aged 18–65 years, belonging to American Society of Anesthesiologists (ASA) physical status I–II, scheduled for elective surgeries under general anaesthesia requiring cuffed polyvinyl chloride (PVC) endotracheal intubation for a duration of 60–120 minutes were included. Inclusion and Exclusion Criteria Patients with BMI between 18.5 and 29.9 kg/m² were included. Exclusion criteria comprised refusal to participate, hemodynamic instability, history of hypertension, asthma, chronic obstructive pulmonary disease, cardiovascular, renal, cerebrovascular disease or diabetes mellitus, hypersensitivity to study drugs, multiple (>3) intubation attempts, airway trauma, recent or active upper respiratory tract infection, nasogastric tube placement, and prior use of systemic or inhaled steroids or analgesics. Sample Size Based on an assumed incidence of postoperative sore throat (POST) of 53.3% in the magnesium sulphate group and 86.7% in the control group, sample size was calculated using OpenEpi12. With a confidence level of 95% and power of 80%, 78 patients were required. To account for dropouts, 90 patients were enrolled and equally allocated into three groups (30 per group). Randomization and Blinding Study was prospective, randomized, controlled,triple bind study. Randomization was performed using a computer-generated random number sequence. Allocation concealment was ensured using sequentially numbered opaque sealed envelopes. The study drugs were prepared by an anaesthesiologist not involved in patient management or data collection. The anaesthesiologist doing the intervention and anaesthesiologist observing the patient both were blinded to the study group. An independent,blinded observer (anaesthesiologist not involved with the case) collected the postoperative data. Patients were also blinded to the drugs used for nebulization. Interventions Patients were randomly allocated into three groups: • Group I received nebulized magnesium sulphate 250 mg (2.5 ml) diluted with 2.5 ml normal saline. • Group II received nebulized lignocaine 2% (100 mg, 5 ml). • Group III received nebulized normal saline 5 ml. Nebulization was administered over 15 minutes in the preoperative area with continuous monitoring. Anaesthetic and Intubation Protocol All patients received standardized general anaesthesia, including premedication, induction, intubation with low-pressure high-volume cuffed PVC endotracheal tubes, maintenance, and extubation. Endotracheal tube cuff pressures were maintained between 20–25 mmHg. Intubation was performed by the same anaesthesiologist to reduce procedural bias. Outcome Assessment Primary outcomes included the incidence and severity of postoperative sore throat, postoperative cough, and postoperative hoarseness of voice. Secondary outcomes included extubation quality and patient satisfaction. Assessments were performed at 2, 6, 12, 24, and 48 hours postoperatively using standardized grading scales by a blinded observer. Statistical Analysis Data were collected in a predesigned proforma and analyzed using appropriate statistical methods. Continuous variables were expressed as mean ± standard deviation, while categorical variables were expressed as frequencies and percentages. A p-value <0.05 was considered statistically significant.

The three groups were comparable with respect to baseline socio-demographic characteristics. There was no statistically significant difference in mean age, gender distribution, type of surgery performed, or body mass index among Group I, Group II, and Group III (p > 0.05 for all), indicating adequate baseline homogeneity. (Table 1) Extubation quality scores differed significantly among the three groups. Group I demonstrated the best extubation quality, with the majority of patients having a score of 1, followed by Group II and Group III. The overall intergroup comparison showed a statistically significant difference (p = 0.013). Pairwise analysis revealed a significant difference between Group I and Group III (p = 0.006), while differences between Group I and Group II and between Group II and Group III were not statistically significant. (Table 2) The mean extubation quality score was highest in Group I and lowest in Group III, with a significant overall difference (p = 0.005). Post-hoc analysis confirmed a statistically significant difference between Group I and Group III (p = 0.004), indicating superior extubation quality in Group I. (Table 2) Postoperative heart rate, systolic blood pressure, diastolic blood pressure, and mean arterial pressure were compared among Group I, II, and III at 2, 6, 12, 24, and 48 hours. No statistically significant differences were observed between the groups at any time point (p > 0.05) (Figure 1a–d). Postoperative sore throat was absent initially and occurred more frequently in Group III at later time points, with a significant difference between Group I and Group III at 12 hours.(Table 3) No cough was observed in the early postoperative period. A higher incidence was noted in Group III at 48 hours, with a significant difference between Group I and Group III.(Table 4) Postoperative hoarseness was rare, occurring only in Group III, with no significant intergroup differences.(Table 5) Table 1: Sociodemographic characteristics of the study Variable Group I (n = 30) Group II (n = 30) Group III (n = 30) p value Age Mean ± SD (years) 45.03 ± 11.56 44.93 ± 12.32 46.70 ± 11.10 0.805‡ Gender Female 25 (83.33%) 21 (70.00%) 25 (83.33%) 0.344† Male 5 (16.67%) 9 (30.00%) 5 (16.67%) Type of Surgery Laparoscopic cholecystectomy 23 (76.67%) 25 (83.33%) 19 (63.33%) 0.617* Laparoscopic cystectomy 2 (6.67%) 2 (6.67%) 5 (16.67%) Left MRM 2 (6.67%) 1 (3.33%) 1 (3.33%) Right MRM 3 (10.00%) 2 (6.67%) 5 (16.67%) Body Mass Index Mean ± SD (kg/m²) 23.25 ± 0.98 23.25 ± 0.84 22.76 ± 0.92 0.059‡ † Chi-square test‡ One-way ANOVA Table 2: Comparison of extubation quality score between group I, II and III Extubation quality score Group I (n=30) Group II (n=30) Group III (n=30) P value 1 29 (96.67%) 26 (86.67%) 20 (66.67%) 0.013* 2 1 (3.33%) 4 (33.33%) 9 (30%) I vs II: 0.125* 3 0 (0%) 0 (0%) 1 (3.33%) II vs III: 0.353* I vs III: 0.006* Mean ± SD 1.37 ± 0.35 1.13 ± 0.56 1.03 ± 0.18 0.005‡ I vs II: 0.061 II vs III: 0.587 I vs III: 0.004 * Fisher’s exact test‡ ANOVA Figure 1a:-Comparison of trend of postoperative heart rate at different time intervals between group I, II and III.Figure 1b:-Comparison of trend of postoperative systolic blood pressure at different time intervals between group I, II and III.Figure 1c:-Comparison of trend of postoperative diastolic blood pressure at different time intervals between group I, II and III.Figure 1d:-Comparison of trend of postoperative SpO₂ at different time intervals between group I, II and III.   Figure 1. Comparison of postoperative hemodynamic parameters between Group I, II and III Table 3. Comparison of Postoperative Sore Throat Between Group I, II and III Postoperative sore throat Group I (n = 30) Group II (n = 30) Group III (n = 30) P value At 2 hours 0 (0%) 0 (0%) 0 (0%) NA At 6 hours 0 (0%) 0 (0%) 1 (3.33%) 1.0* I vs II: NA I vs III: 1.0* II vs III: 1.0* At 12 hours 0 (0%) 5 (16.67%) 6 (20%) 0.071* I vs II: 0.041* I vs III: 0.044* II vs III: 1.0* At 24 hours 2 (6.67%) 5 (16.67%) 6 (20%) 0.413* I vs II: 0.424* I vs III: 0.254* II vs III: 0.739† At 48 hours 0 (0%) 1 (3.33%) 3 (10%) 0.318* I vs II: 1.0* I vs III: 0.237* II vs III: 0.612* * Fisher’s Exact Test† Chi-square test Table 4. Comparison of Postoperative Cough Between Group I, II and III Postoperative cough Group I (n = 30) Group II (n = 30) Group III (n = 30) P value At 2 hours 0 (0%) 0 (0%) 0 (0%) NA At 6 hours 0 (0%) 0 (0%) 0 (0%) NA At 12 hours 0 (0%) 0 (0%) 0 (0%) NA At 24 hours 0 (0%) 2 (6.67%) 2 (6.67%) 0.54* I vs II: 0.492* I vs III: 0.492* II vs III: 1.0* At 48 hours 0 (0%) 2 (6.67%) 5 (16.67%) 0.065* I vs II: 0.492* I vs III: 0.042* II vs III: 0.424* * Fisher’s Exact Test Table 5. Comparison of Postoperative Hoarseness of Voice Between Group I, II and III Postoperative hoarseness of voice Group I (n = 30) Group II (n = 30) Group III (n = 30) P value At 2 hours 0 (0%) 0 (0%) 0 (0%) NA At 6 hours 0 (0%) 0 (0%) 0 (0%) NA At 12 hours 0 (0%) 0 (0%) 0 (0%) NA At 24 hours 0 (0%) 0 (0%) 1 (3.33%) 1.0* I vs II: NA I vs III: 1.0* II vs III: 1.0* At 48 hours 0 (0%) 0 (0%) 1 (3.33%) 1.0* I vs II: NA I vs III: 1.0* II vs III: 1.0* * Fisher’s Exact Test

Postoperative sore throat, cough, and hoarseness of voice are common yet often under-recognized complications following endotracheal intubation under general anaesthesia. Although generally self-limiting, these airway-related morbidities significantly affect postoperative comfort, patient satisfaction, and overall perioperative experience. Strategies aimed at reducing airway irritation are therefore clinically relevant13. The present study evaluated the effectiveness of preoperative nebulization with magnesium sulphate and lignocaine in attenuating these complications and improving extubation quality, while maintaining hemodynamic stability. The study groups were comparable with respect to age, gender distribution, body mass index, and type of surgery, ensuring adequate baseline homogeneity and minimizing confounding influences. Hemodynamic parameters, including heart rate, systolic and diastolic blood pressure, mean arterial pressure, and oxygen saturation, remained comparable among the three groups throughout the postoperative period. These findings indicate that nebulized magnesium sulphate and lignocaine do not produce clinically significant systemic or cardiovascular effects, supporting their safety in the perioperative setting. Similar hemodynamic stability with nebulized magnesium sulphate has been reported by Yadavet al.14, who demonstrated minimal systemic absorption and negligible cardiovascular impact at comparable doses. Postoperative sore throat was not observed in the immediate postoperative period and became evident primarily after 12 hours. The incidence was lowest in the magnesium sulphate group, followed by the lignocaine and control groups, with a significant reduction noted with magnesium sulphate compared to control at later postoperative intervals. This protective effect is likely related to the anti-inflammatory properties of magnesium sulphate and its action as an NMDA receptor antagonist, which reduces cytokine release, airway inflammation, and mucosal edema. In contrast, lignocaine acts predominantly through sodium channel blockade, providing local anesthetic effects of shorter duration and limited anti-inflammatory action. These findings are consistent with those of Kalaniet al.15 and Rajanet al16, who demonstrated a lower incidence of postoperative sore throat with nebulized magnesium sulphate compared to lignocaine or placebo. Kamel AAF et al.17 also reported superior protection against postoperative sore throat with magnesium sulphate, with effects persisting up to 24 hours. The present study further supports these observations, reinforcing the role of magnesium sulphate as an effective agent in reducing both the incidence and severity of postoperative sore throat. Postoperative cough followed a similar temporal pattern, being absent in the early postoperative period and occurring predominantly between 24 and 48 hours. Magnesium sulphate was associated with the lowest incidence of postoperative cough, while the highest incidence was observed in the control group. A statistically significant difference was noted between magnesium sulphate and control groups at 48 hours, suggesting a sustained protective effect of magnesium on airway reflexes. Rajanet al.16 reported comparable findings, demonstrating reduced airway complications, including cough, in patients receiving magnesium-based nebulization. Although fewer studies have specifically evaluated postoperative cough, the available literature supports the observed trend of reduced airway irritation with magnesium sulphate. Postoperative hoarseness of voice was rare in the present study and occurred only in the control group at later postoperative intervals. No patient receiving magnesium sulphate or lignocaine developed hoarseness. Kalaniet al.15 observed hoarseness in both magnesium and lignocaine groups, though with faster resolution in the magnesium group. The absence of hoarseness in the intervention groups in the present study may reflect reduced laryngeal irritation and smoother emergence, although the low incidence limits definitive conclusions. Larger studies are required to further clarify the comparative effectiveness of these agents in preventing postoperative hoarseness of voice. Extubation quality is a critical determinant of postoperative airway morbidity. In the present study, magnesium sulphate was associated with superior extubation quality compared to the control group, reflected by a higher proportion of patients achieving optimal extubation scores. This smoother extubation likely contributes to the reduced incidence of postoperative airway complications observed with magnesium sulphate. While the difference between magnesium sulphate and lignocaine did not reach statistical significance, the overall trend favored magnesium sulphate, consistent with its anti-inflammatory and membrane-stabilizing properties. Overall, the findings of the present study align well with existing literature and demonstrate that preoperative nebulization with magnesium sulphate is a safe, effective, and cost-effective intervention for reducing postoperative sore throat and cough, while also improving extubation quality without compromising hemodynamic stability. Lignocaine nebulization provides partial benefit but appears less effective than magnesium sulphate, particularly at later postoperative intervals. Given its favorable safety profile, ease of administration, and consistent efficacy, nebulized magnesium sulphate may be considered a valuable adjunct in patients undergoing general anaesthesia with endotracheal intubation.

Preoperative nebulization with magnesium sulphate effectively reduces the incidence of postoperative sore throat and cough and improves extubation quality in patients undergoing general anaesthesia with endotracheal intubation, without causing clinically significant hemodynamic instability or adverse effects. Lignocaine nebulization offers partial benefit but is comparatively less effective, particularly at later postoperative intervals. Given its safety, cost-effectiveness, and ease of administration, nebulized magnesium sulphate represents a valuable adjunct for minimizing postoperative airway-related morbidity and enhancing patient comfort in the perioperative period.

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