The present open randomised controlled trial was conducted in March to May 2019, after approval from the college ethical committee of GMC Patiala. Patient consent was taken before conduct of anaesthesia in each case.

Assuming a 5% two-tailed significance level (a=0.05) and power of 80% (b=0.20), to detect 7.05% absolute difference in the incidence of heart rate, a sample size of 96 patients were required for the study. So, 100 patients of either sex were included in this study. The patients were divided randomly into 2 groups Group D (Dexmedetomidine) and Group F (Fentanyl), consisting of 50 patients each, allotted by simple randomisation which was done using chit method.

Inclusion Criteria:

Exclusion Criteria:

A thorough pre-anaesthetic check-up and routine blood investigations were done before surgery in all the patients. Each patient was kept Nil per oral for at least six hours pre-operative and received tablet clonazepam 0.5 mg at 6 am on the day of surgery.

The routine check-up of anaesthesia machine, circuit and resuscitation equipments was done before shifting the fasting patients into the operation theatre. Patients were monitored by a multichannel monitor. Two IV lines using 18G cannula were secured & 500 mL ringer lactate over 30 minutes was given to all patients. After settling in OT for 5minutes, Basal Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Mean Arterial Pressure (MAP), Heart Rate (HR), and SpO₂ were recorded (T0). The vital parameters and ECG were continuously monitored and recorded.

Pre induction included intravenous Inj. Glycopyrrolate 0.2 mg, inj. Ondansetron 4 mg and inj. Ranitidine 50 mg. Also, 100% oxygen was given to all patients.

Group D patients were given inj. Dexmedetomidine 1 μg/kg in 100 mL N.S. intravenous infusion over 10 minutes prior to laryngoscopy and endotracheal intubation. Group F received fentanyl 2 μg/kg in 100 mL N.S. intravenous infusion over 10 minutes before laryngoscopy. HR, SBP, DBP, MAP, SpO₂ were monitored continuously from the entry of the patient in the operation theatre till shifting to the ward and later on but documented at T1 (the start of infusion), at T2 (5 minutes of start of infusion) and at T3 (10 minutes of start of infusion i.e., completion of infusion) in both the groups.

Intravenous Propofol and inhalational isoflurane were used for induction. Loss of eyelash and corneal reflex determined the propofol dose. Succinylcholine was the muscle relaxant used for endotracheal intubation. Disposable, oral cuffed endotracheal tube of adequate size was used. Laryngoscopy was done within 15 seconds in every case by an expert anaesthesiologist.

Anaesthesia was maintained with IPPV using O₂, N₂O, and inhalational anaesthetic like Isoflurane. Muscle relaxant Inj. Vecuronium bromide 0.08 mg/kg to 0.1 mg/kg was given as intravenous bolus according to requirement and maintained as per need. Vital parameters were monitored continuously and recorded at the time of laryngoscopy and intubation (T4) and after laryngoscopy and intubation at 1, 3, 5, 10 minutes (T5 to T8) [Table/Fig-1].

[Table/Fig-1]:

Flow chart depicting the methodology.

Neostigmine 50 μg/kg and glycopyrrolate 10 μg/kg intravenously were used to reverse neuromuscular blockage after surgery. Extubation was done after satisfying extubation criteria and patient was shifted to Post Anaesthesia Care Unit (PACU).

In post anaesthesia care unit, vital monitoring or any untoward event was monitored for atleast 90 minutes after surgery every 10 minutes. When modified Aldrete score >9, patient was shifted to ward.

Fall in BP 20% below baseline and pulse rate <50 beats per minute (bpm) was considered as hypotension and bradycardia respectively and was treated appropriately. Decreased saturation, rise or fall of EtCO₂ was managed according to cause.

After completion of drug infusion, sedation scoring was done as per RAMSAY sedation scale. Adverse effects like hypotension, bradycardia, arrhythmia if present were treated and recorded.

The relevant data on each patient was entered into the proforma and also presented in the master chart. Descriptive statistics was done for all data and suitable statistical tests of comparison were done. Continuous variables were analysed with unpaired t-test and Mann Whitney U test. Categorical variables were analysed with the Chi-square test. Statistical significance was taken as p<0.05, Statisticaly highly significant was taken as p<0.001, Statistical non significance was taken as p>0.05. The observations were depicted in tables. The data was analysed using SPSS (22.00 version) software and Microsoft Excel 2007.

Both groups were comparable and there was no statistically significant difference with regard to age (p=0.9973), sex (p=0.6484), ASA grade (p=0.8414), body weight (p=0.7269) and duration of surgery (p=0.9355).

[Table/Fig-2] shows that the mean heart rate in both the groups was maximum at T₄ but it was remarkably increased (p=0.0465) in Group F showing less attenuation of heart rate by fentanyl compared to dexmedetomidine. [Table/Fig-3] shows that the mean systolic blood pressure decreased initially in both the groups at T₃ but this difference was non-significant. However, there was rise in systolic blood pressure in both the groups at T₄. This rise was significantly lesser in group D (p=0.0187).

[Table/Fig-4] shows that the Diastolic blood pressure rose at T₄ and was significantly better attenuated by dexmedetomidine as compared to fentanyl (p=0.0227). [Table/Fig-5] shows that the mean arterial pressure was also managed significantly better by dexmedetomidine at T₄ (p=0.0092) and at T₅ (p=0.0206).

[Table/Fig-6] shows that no statistically significant difference (p-values >0.05) was found in SpO₂ between two groups and both groups were comparable at T₀-T₈.

[Table/Fig-7] shows that no statistically significant difference (p-values >0.05) was found in EtCO₂ between two groups and both groups were comparable at T₀-T₈.

The difference in mean dosage of propofol during induction was non-significant in both the groups (p=0.1580). Also the Ramsay Sedation scale score (p=0.5499) and Modified Aldrete score was comparable in both the groups.

This study was done to know which of these two drugs i.e that dexmedetomidine and fentanyl in achieving haemodynamic stability during intubation.

There was increase in heart rate at T₄ and T₅ in both the groups. However, the magnitude of increase in heart rate at T₄ and T₅ was higher in Group F as compared to Group D (p-value <0.05) showing dexmedetomidine is better in attenuating heart rate than fentanyl.

This is in concordance to literature as similar observations were made by Patel CR et al., in their study [10]. However, the findings are somewhat in contrast with the results of Kharwar RK et al., and Jain V et al., who observed that heart rate was decreased from baseline after laryngoscopy and intubation in both groups, but the decrease was more in Dexmedetomidine group as compared to fentanyl group [11,12].

The difference between mean systolic blood pressure at T₀, T₁, T₂, T₃ was statistically insignificant (p >0.05). However, this study demonstrated that the mean SBP rose in both groups at T4 and T5. But it’s rise was statistically more in Group F than Group D (p-value <0.05). This shows that dexmedetomidine is more efficacious in controlling systolic blood pressure during intubation as compared to fentanyl.

In the study conducted by Patel CR et al., it was observed that Dexmedetomidine significantly attenuated stress response at intubation compared with fentanyl [10]. This is similar to our study. Jain V et al., also observed that Dexmedetomidine produced more significant attenuation of increase in SBP during laryngoscopy and intubation as compared with fentanyl, which is in concordance with our study [12].

The difference between mean diastolic blood pressure at T₀, T₁, T₂, T₃ in the two groups was statistically insignificant (p-values >0.05). The mean diastolic blood pressure at T₄ in Group D was 92.73±6.679 mmHg and it was 97.01±6.167 mmHg in Group F. Significant difference was found in the mean diastolic blood pressure between two groups at T₄ (p-value=0.0227). The mean diastolic blood pressure at T₅ in Group D was 85.57±7.947 mmHg and was 90.29±6.679 mmHg in Group F. This difference was significant (p-value=0.0275). The difference between mean diastolic blood pressure at T₆, T₇, T₈ in both groups was statistically insignificant (p-values >0.05).

The results are in concordance with that of Jain V et al., who observed a significant increase in DBP during laryngoscopy and intubation with fentanyl group as compared to Dexmedetomidine group [12].

No statistically significant difference (p-values >0.05) was found in mean arterial pressure between two groups and both groups were comparable at T₀, T₁, T₂, T₃. The mean arterial blood pressure at T₄ in Group D was 107.40±6.167 mmHg and it was 112.24±6.435 mmHg in Group F which was statistically significant (p-value=0.0092). The mean value of mean arterial blood pressure at T₅ in Group D was 99.10±7.142 mmHg and was 104.18±7.845 mmHg in Group F (p-value=0.0206). The mean arterial blood pressure was insignificant in both the groups at T₆, T₇, T₈. These results are in concordance with that of earlier literature [13].

In this study, the mean dose of propofol used for induction in Group D was 103.10±15.79 mg and in Group F was 108.70±11.48 mg. This difference in dose was statistically insignificant in both the groups (p-value=0.1580) nullifying any contributory role of propofol in attenuating haemodynamic responses.

No patient in this study had bradycardia (HR <50 bpm), hypotension (SBP <90 mmHg or DBP <60 mmHg or MAP <50 mmHg) or arrhythmias. Vitals were also stable in Post-operative Anaesthesia Care Unit (PACU).

Cost of drug is an important factor and in this RCT, cost effectiveness analysis was not conducted. Levels of drug in blood were not measured. Bispectral Index (BIS) was not used to measure depth of anaesthesia. Neuromuscular monitoring was not used in this RCT.

Dexmedetomidine significantly decreased the sympathetic response of laryngoscopy and intubation as compared to Fentanyl, so Dexmdetomidine is superior to Fentanyl in attenuation of haemodynamic response during laryngoscopy and intubtion. On the basis of this study, an intravenous bolus dose of dexmedetomidine 1 μg/kg in 100 mL N.S. is recommended to be administered over 10 minutes before laryngoscopy and intubation especially in high risk patients.