European Journal of Cardiovascular Medicine

The management of the airway is one of the most important aspects of general anaesthesia, and the development of supraglottic airway devices has provided an effective alternative to endotracheal intubation in selected surgical procedures [1]. The laryngeal mask airway (LMA) introduced a new approach to airway management by providing an airway device that could be inserted without the need for direct laryngoscopy or tracheal intubation [1]. Adequate depth of anaesthesia is essential during insertion of supraglottic airway devices to prevent airway-related responses such as coughing, gagging, breath-holding and laryngospasm [2]. Fentanyl, an opioid analgesic, is commonly used as an adjunct to propofol induction because it reduces the dose of propofol required for successful airway device insertion [3]. The combination of ketamine and propofol has also been used to provide anaesthesia

while potentially balancing the cardiovascular effects of the two drugs [4].

The I-Gel is a second-generation supraglottic airway device designed with a non-inflatable, anatomically shaped cuff that provides a seal around the perilaryngeal structures [5]. Its design facilitates insertion and avoids the need for cuff inflation, while also providing a gastric channel for selected device sizes [6]. Successful insertion of the I-Gel depends on adequate jaw relaxation, sufficient depth of anaesthesia and minimal airway reflex responses [6]. The choice of co-induction agent with propofol may therefore influence insertion conditions, the number of attempts required and the overall success of airway placement [7]. Previous studies comparing ketamine-propofol and fentanyl-propofol combinations have reported differences in haemodynamic responses and conditions for supraglottic airway insertion [8]. Comparative evaluations have also demonstrated that the choice of adjunctive drug may influence coughing, gagging, patient movement and the requirement for additional propofol during airway device insertion [9].

Both ketamine and fentanyl have distinct pharmacological properties that may influence the quality of induction and recovery. Ketamine produces dissociative anaesthesia and has sympathomimetic properties, whereas fentanyl provides analgesia and attenuates sympathetic responses to airway manipulation [7,10]. Although propofol provides rapid induction and recovery, its use may be associated with dose-dependent cardiovascular and respiratory depression. The addition of an appropriate co-induction agent may improve insertion conditions and reduce the total propofol requirement [3,8]. However, the relative advantages of ketamine and fentanyl when combined with propofol for I-Gel insertion require further evaluation in adult patients undergoing short surgical procedures. Therefore, the present study was undertaken to compare intravenous fentanyl and ketamine as co-induction agents with intravenous propofol, focusing on ease of I-Gel insertion, insertion success, haemodynamic responses, recovery characteristics and perioperative complications.

A comparative prospective observational study was conducted among 60 adult patients of either gender, aged between 18 and 60 years, undergoing elective minor surgical procedures of less than 60 minutes anticipated duration under general anaesthesia using an I-Gel supraglottic airway device. Institutional Ethics Committee approval was obtained before commencement of the study, and written informed consent was taken from all participants. Patients were divided into two groups according to the co-induction agent administered, with 30 patients in each group. Group I received intravenous ketamine 0.5 mg/kg followed by intravenous propofol 2.5 mg/kg, whereas Group II received intravenous fentanyl 1 µg/kg followed by intravenous propofol 2.5 mg/kg.

Patients belonging to American Society of Anesthesiologists (ASA) physical status I and II, with Mallampati grade I or II and normal head and neck movements, were included. Patients with mouth opening less than 2.5 cm, known difficult airway, cervical spine disease, risk of aspiration, allergy to either study drug, head injury, chronic drug or alcohol abuse, psychiatric disorders or refusal to participate were excluded from the study. Pre-anaesthetic evaluation was performed before surgery, including detailed medical and surgical history, general and systemic examination, airway assessment and relevant routine investigations. Baseline heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure and peripheral oxygen saturation were recorded.

On arrival in the operating theatre, intravenous access was secured, intravenous fluids were initiated and standard anaesthesia monitoring was established. All patients were premedicated with intravenous ondansetron 0.08 mg/kg and glycopyrrolate 0.004 mg/kg. Pre-oxygenation was performed with 100% oxygen for three minutes. Patients were then administered the allocated co-induction drug, followed by intravenous propofol 2.5 mg/kg. Additional propofol 0.5 mg/kg was administered when required to achieve adequate depth of anaesthesia. An appropriately sized I-Gel was selected according to the patient's body weight, lubricated with water-based hydrating jelly and inserted with the patient in the sniffing position. The device was advanced along the hard palate until definite resistance was felt. In case of unsuccessful insertion, a further attempt was made after administering an additional propofol dose of 0.5 mg/kg. A maximum of three insertion attempts was permitted. Successful placement was confirmed by bilateral symmetrical chest expansion, an appropriate square-wave capnography trace and absence of an audible air leak.

The ease of insertion was assessed as easy or difficult. Easy insertion was defined as insertion without resistance in a single manoeuvre with adequate jaw relaxation, while difficult insertion was considered when resistance or additional manoeuvres such as jaw thrust, chin lift, gentle pushing or pulling, head extension or neck flexion were required. Jaw relaxation was assessed according to Young's criteria. The number of attempts required for successful I-Gel insertion was recorded. Overall insertion conditions were assessed using the Modified Scheme of Lund and Stovener and classified as excellent, good, poor or unacceptable according to the presence and severity of coughing, gagging, patient movement and laryngospasm.

Heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure and peripheral oxygen saturation were recorded at baseline, immediately after I-Gel insertion, at 1, 3, 5 and 10 minutes, and subsequently at 10-minute intervals until the completion of surgery. The I-Gel was connected to a Bain's circuit, and anaesthesia was maintained with 50% oxygen, 50% nitrous oxide and sevoflurane. Additional intravenous propofol was administered when haemodynamic parameters changed by more than 20% from baseline. Intraoperative complications, including hypotension, bradycardia, apnoea, respiratory depression, coughing, gagging, involuntary movements and bronchospasm, were recorded. At the end of surgery, anaesthetic agents were discontinued and the I-Gel was removed when the patient was adequately arousable, able to open the mouth and following verbal commands after gentle suctioning. Recovery time and awakening time were documented. Patients were monitored in the postoperative ward for 20 minutes, and complications such as sore throat, hoarseness of voice, nausea, vomiting, shivering, blood staining of the device and lip, tongue or dental trauma were recorded.

The collected data were compiled and analysed statistically. Continuous variables were expressed as mean and standard deviation, while categorical variables were presented as frequencies and percentages. Unpaired Student's t-test was used for comparison of continuous variables between the two groups, and the Chi-square test was used for categorical variables. A p-value of less than 0.05 was considered statistically significant.

Table 1 shows the demographic characteristics of patients in both groups. The mean age was 32.50 years in Group I and 36.37 years in Group II. The male-to-female ratio was 9:21 in Group I and 10:20 in Group II. The mean body weight was 51.03 kg and 52.37 kg in Group I and Group II, respectively. In Group I, 20 patients belonged to ASA grade I and 10 to ASA grade II, whereas Group II included 14 patients with ASA grade I and 16 with ASA grade II. The mean duration of surgery was 35.17 minutes in Group I and 37 minutes in Group II. No statistically significant differences were observed between the groups for any of these demographic parameters (p>0.05).

Table 2 shows the ease of I-Gel insertion and the number of attempts required in both groups. Easy insertion was observed in 24 (80%) patients in Group I and 28 (93.33%) patients in Group II, whereas difficult insertion was noted in 6 (20%) and 2 (6.67%) patients, respectively. First-attempt insertion was successful in 24 (80%) patients in Group I and 26 (86.67%) patients in Group II. Second-attempt insertion was required in 6 (20%) patients in Group I and 4 (13.33%) patients in Group II. No patient required a third attempt. Successful I-Gel insertion was achieved within two attempts in all patients in both groups.

Table 3 shows the overall insertion conditions assessed according to the Lund and Stovener criteria. Excellent insertion conditions were observed in 18 (60%) patients in Group I and 29 (96.67%) patients in Group II. Good conditions were recorded in 9 (30%) patients in Group I and 1 (3.33%) patient in Group II. Poor insertion conditions were observed in 3 (10%) patients in Group I, while no patients in Group II had poor conditions. No unacceptable insertion conditions were recorded in either group.

Table 4 shows the comparison of heart rate changes between Group I and Group II at different time intervals. The baseline heart rate was comparable between the two groups, with no statistically significant difference (p=0.4627). Immediately after I-Gel insertion, the mean heart rate increased to 94.93±5.65 beats/min in Group I compared with 80.73±6.02 beats/min in Group II. The difference remained statistically significant at 1, 3, 5, 10 and 20 minutes (p<0.05). These findings indicate a greater increase in heart rate in Group I during the initial period following I-Gel insertion.

Table 5 shows the comparison of systolic blood pressure (SBP) between Group I and Group II at different time intervals. The baseline SBP was comparable between the two groups, with no statistically significant difference (p=0.1598). Immediately after I-Gel insertion, the mean SBP increased to 129.00±4.66 mmHg in Group I, whereas it was 112.40±4.12 mmHg in Group II. Statistically significant differences were observed immediately after insertion and at 1, 3, 5, 10, 20 and 30 minutes (p<0.05). These findings demonstrate a greater rise in systolic blood pressure in Group I compared with Group II during the initial period after I-Gel insertion.

TABLE 1: Demographic Data

TABLE 2: Ease of insertion and Number of attempts

TABLE 3: Overall condition of patients

TABLE 4: Changes in heart rate (mean ± SD)

TABLE 5: Changes in systolic blood pressure (mean ± SD)

The present study compared ketamine and fentanyl as co-induction agents with propofol for I-Gel insertion in adult patients undergoing short surgical procedures. The study evaluated insertion conditions, number of attempts, haemodynamic responses, oxygen saturation, recovery characteristics and perioperative complications. The findings demonstrated differences between the two groups, particularly in insertion conditions and haemodynamic responses.

In the present study, demographic characteristics, including age, sex, body weight, ASA physical status and duration of surgery, were comparable between Group I and Group II. This comparability indicates that the two groups had similar baseline characteristics for evaluating the effects of the co-induction agents.

Regarding ease of I-Gel insertion, easy insertion was observed in 80% of patients in Group I and 93.33% of patients in Group II. First-attempt insertion was successful in 80% of Group I patients and 86.66% of Group II patients. Furthermore, the overall insertion conditions were rated excellent in 60% of Group I patients compared with 96.67% of Group II patients. These findings indicate better insertion conditions with fentanyl-propofol than with ketamine-propofol in the present study. The comparative work by Nagalakshmi et al. [12], which evaluated different co-induction agents with propofol for LMA insertion, provides relevant context for assessing the influence of the selected drug combination on airway insertion conditions.

The haemodynamic findings showed a greater increase in heart rate in Group I than in Group II during the initial period following I-Gel insertion. Although baseline heart rates were comparable, the difference was statistically significant immediately after insertion and at 1, 3, 5, 10 and 20 minutes. Similarly, systolic blood pressure was significantly higher in Group I from immediately after insertion through 30 minutes. Diastolic blood pressure and mean arterial pressure also showed significantly higher values in Group I during the early observation period. These findings suggest that the fentanyl-propofol combination provided better attenuation of the haemodynamic response associated with I-Gel insertion. The comparison of propofol-based drug combinations reported by Arikan et al. [11] and the evaluation of fentanyl-propofol for I-Gel insertion by Rustagi et al. [13] provide relevant background for interpreting these observations.

Oxygen saturation remained comparable between the two groups throughout the observation period, with no statistically significant differences at any recorded time point. This indicates that both drug combinations maintained adequate oxygenation during the observed period in the study population.  Alex et al. [14], who evaluated the insertion characteristics of I-Gel and classic LMA, provide additional context regarding the use and assessment of supraglottic airway devices.

The findings related to haemodynamic stability can also be considered alongside the study by Nagalakshmi et al. [12], who compared butorphanol, fentanyl and ketamine as co-induction agents with propofol for LMA insertion. They reported excellent insertion conditions in 50% of patients receiving ketamine-propofol and 83.3% of patients receiving fentanyl-propofol. However, their study found a more stable haemodynamic profile with ketamine than with fentanyl. This differs from the haemodynamic pattern observed in the present study, where the fentanyl-propofol group showed lower heart rate and blood pressure values during the early post-insertion period. Differences in study design, patient characteristics and drug combinations may contribute to the variation in findings.

Arikan et al. [11] compared propofol-remifentanil and propofol-ketamine combinations and reported lower heart rate and mean blood pressure values in the remifentanil group, while the ketamine group demonstrated better haemodynamic stability. Although their study involved a different opioid and a different surgical procedure, it highlights that haemodynamic responses may vary according to the co-induction agent used. [11]

Nerurkar et al. [15] evaluated the propofol dose required for successful insertion of I-Gel and classic LMA and reported that I-Gel required a significantly lower propofol dose than classic LMA. Their findings support the importance of considering the airway device and anaesthetic requirements when evaluating insertion conditions.

Rustagi et al. [13] compared dexmedetomidine-propofol with fentanyl-propofol for I-Gel insertion and reported comparable overall insertion conditions between the two groups. Their findings indicate that different co-induction combinations can provide satisfactory conditions for I-Gel insertion. Alex et al. [14] compared the insertion characteristics of I-Gel and classic LMA when used by first-time users, further highlighting the importance of insertion characteristics in the selection and assessment of supraglottic airway devices.

Overall, the present study demonstrated that fentanyl-propofol provided better I-Gel insertion conditions and greater attenuation of the early haemodynamic response than ketamine-propofol. Both combinations maintained comparable oxygen saturation throughout the observation period. These findings suggest that fentanyl may be a useful co-induction agent with propofol for I-Gel insertion in adult patients undergoing short surgical procedures.

The present study concludes that fentanyl (1 µg/kg) combined with propofol (2.5 mg/kg) provides better I-Gel insertion conditions than ketamine (0.5 mg/kg) combined with propofol (2.5 mg/kg). The fentanyl-propofol combination was associated with a higher proportion of excellent insertion conditions, fewer difficult insertions and better attenuation of the early haemodynamic response. Both groups maintained comparable oxygen saturation during the observation period. Therefore, fentanyl-propofol may be considered a suitable combination for facilitating I-Gel insertion in adult patients undergoing short surgical procedures.

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