One of the basic skills of general anaesthetic is endotracheal intubation and is frequently used to secure and maintain an adequate airway during surgery [1].

 Laryngoscopy and endotracheal tube intubation are necessary for airway management and for sufficient ventilation, but can result in a transient, clinically significant hemodynamic response [2]. The laryngoscopy stimulates the oropharyngeal and laryngeal structures leading to activation of the sympathetic nervous system with cardiovascular parameter changes, including increased heart rate and arterial blood pressure [3]. These responses can be exaggerated when there are underlying cardiovascular disease, hypertension, cerebrovascular disease, or other conditions that allow changes in haemodynamic status to be poorly tolerated [4].

The traditional direct laryngoscopy technique demands that the oral, pharyngeal and laryngeal axes align to achieve a good visualization of the glottis [5]. This procedure usually requires a lot of manipulation of the tongue and soft tissues and it is likely to need more force when inserting the blade and raising it [6]. Mechanical stimulation may have the effect of enhancing sympathetic activation and, as a result, raise heart rate and thus arterial blood pressure after tracheal intubation [7]. These changes can also be affected by the length and the difficulty of laryngoscopy, the number of attempts to intubate, and the physiological reaction of the patient [8].

Video laryngoscopy is now an alternative to the traditional laryngoscopy for tracheal intubation. Video laryngoscopes have a camera or optical system near the distal end of the blade, which enables the glottic structures to be seen on a monitor unlike conventional direct laryngoscopy [9]. This design can aid in visualization of the larynx and may decrease the need for excessive airway axis alignment and the amount of tissue manipulation needed to achieve successful intubation [10]. But, despite this technical difference, video laryngoscopy can induce a sympathetic cardiovascular response with the insertion of the blade and passage of the endotracheal tube.

The immediate cardiovascular response to airway manipulation is usually evaluated by heart rate and mean arterial pressure [11]. Measuring such parameters following endotracheal intubation can offer a clinically useful way to assess the hemodynamic changes of different laryngoscopic techniques and compare their effects. Variations in the size of post-intubation changes may be due to the level of stimulation and procedural stress each intubation technique causes [12].

Previous studies have compared video and conventional laryngoscopy, but did not consistently demonstrate consistent differences in immediate hemodynamic response due to different populations, laryngoscope types and anesthetic protocols. There is limited evidence from young, low-risk patients, undergoing elective surgery, in the local context. Thus, a randomized study to compare heart rate and mean arterial pressure after intubation under a similar anesthetic regimen is justified.

Research Objective

The objective of this study was to compare the mean heart rate and mean arterial pressure after endotracheal intubation using conventional versus video laryngoscopy.

Study Design The purpose of this study was to compare the immediate hemodynamic changes after endotracheal intubation performed with conventional laryngoscopy versus with video laryngoscopy (VL), in a randomized controlled trial. Study Setting The study was performed in the Department of Anesthesiology, Lahore general hospital, Lahore. Study Duration The study was carried out for a duration of six months from 02nd May 2020 to 01st November 2020 after approval of the study synopsis. Sample Size Total number of sample size was 60 patients with 30 patients in each group. A 95% two-sided confidence interval with 80% power of the test was used to calculate the sample size. This calculation was based on an expected mean heart rate after endotracheal intubation after conventional laryngoscopy or video laryngoscopy in patients under general anesthesia (93.22 ± 14.74 beats per minute and 82.32 ± 10.30 beats per minute, respectively) [13]. Sampling Technique A non-probability consecutive sampling technique was used to recruit the patients who met the predefined criteria for eligibility. Inclusion and Exclusion Criteria Patients of either gender aged 18–40 years who were scheduled for elective surgery under general anesthesia requiring endotracheal intubation were included in the study. Elective surgery performed were mastectomy, cholecystectomy, abdominal hernia, renal stone extraction, and vesical stone extraction. Patients who gave written informed consent to participate in the study were included. Patients with an American Society of Anesthesiologists (ASA) physical status of III or above were excluded from the study. Patients who had an ejection fraction < 50% on echocardiography also were excluded. Patients with hypertension (BP>140/90 mmHg on at least 2 occasions at least 4 hours apart) were excluded. Fasting blood glucose > 110 mg/dL was also considered a cutoff for diabetes mellitus. The obese patients (BMI > 30 kg/m²) and those with peripheral vascular disease (PVD) on history and examination were excluded. Data Collection Procedure After obtaining approval from the Ethical Review Board of the Hospital, 60 patients with endotracheal intubation who were operated under general anesthesia for elective surgeries at Lahore General Hospital, Lahore, were recruited for the study in accordance with inclusion and exclusion criteria.After approval from the Ethical Review Board of the Hospital, 60 patients undergoing elective surgery under general anesthesia with endotracheal intubation fulfilled the inclusion and exclusion criteria and were enrolled in the study at Lahore General Hospital Lahore. Each eligible patient was informed of the details of the study procedure and informed consent was obtained. A detailed history was obtained from each participant. These patients were then divided into two groups by randomizing them, using the lottery technique. Patients were divided into two groups: Group A were patients who were intubated by conventional laryngoscopy, and Group B were patients who were intubated by video laryngoscopy. All patients were given standard premedication on the operating table of Dormicum (midazolam) 2–3 mg intravenously. Electrocardiography, pulse oximetry and non-invasive blood pressure monitoring were used to establish standard monitoring. Baseline HR, SBP, DBP, MAP and AaO2 were obtained prior to induction. Nalbuphine 1 mg/kg was given intravenously after pre-oxygenation. General anesthesia was administered by propofol 2 mg/kg intravenously for induction of sleep followed by atracurium 0.5 mg/kg to produce neuromuscular blockade. The patients were manually ventilated with oxygen and isoflurane at an end-tidal concentration of 1% using a facemask. After three minutes of induction, the laryngoscopy and endotracheal intubation were done. For group A, some of the patients were intubated orally with a Macintosh laryngoscope. The correct size endotracheal tube was chosen based on the patient's body size. Intubation without pre/intubation lignocaine. For Group B, a video laryngoscope blade was used to place an appropriate sized ET tube along the groove. The endotracheal tube was inserted just beyond the tip of the charge coupled device camera and the blade was pushed into the glottic area under the vision of the CCD camera. The video laryngoscope display was used to visualize and centrate the glottis and the endotracheal tube was then advanced into the trachea. After successful endotracheal intubation, HR and MAP were measured and recorded 1 minute later. The researcher used a structured data collection proforma to record the demographic characteristics, baseline heart rate, baseline mean arterial pressure, and post-intubation data. Confounding variables were eliminated by using a standardized anesthetic and intubation protocol for all participants and through the predetermined exclusion criteria. Data Analysis Procedure The data gathered were entered, coded and analyzed with the assistance of SPSS version 17.0. For numerical variables, such as age, BMI, baseline heart rate, baseline mean arterial pressure, post-intubation heart rate and post-intubation mean arterial pressure, the values were expressed as mean standard deviation. Heart rate and MBP were compared between the two groups after intubation using independent-samples t-test. A p-value of ≤0.05 was considered statistically significant. Qualitative data such as ASA physical status and gender were summarized in frequencies and percentages. The factors were stratified by age, gender, BMI, ASA physical status, baseline heart rate, and baseline mean arterial pressure, to evaluate their possible influence on the study results. An independent-samples t-test was used to examine the appropriate continuous variables between the two groups after stratification. The values p<0.05 were taken as statistically significant.

Table 1 shows the baseline characteristics of the 60 participants. The mean age was 28.17 ± 6.49 years, with 65.0% aged 18–29 years and 35.0% aged 30–40 years. Males comprised 61.7% of participants and females 38.3%. The mean BMI was 24.09 ± 2.29 kg/m², while 55.0% of participants were ASA Class I and 45.0% were Class II. The mean baseline heart rate was 74.77 ± 3.90 beats/min and the mean baseline MAP was 93.72 ± 3.41 mmHg.

Table 1: Baseline Characteristics of the Study Population (n=60)

Table 2 demonstrates that the two study groups were comparable at baseline. Mean age was 28.13 ± 6.38 years in the video laryngoscopy group and 28.20 ± 6.71 years in the direct laryngoscopy group (p=0.969). Similarly, no significant differences were observed in gender, BMI, ASA status, baseline heart rate, or baseline MAP, with all p-values >0.05, indicating balanced baseline characteristics between the groups.

Table 2: Comparison of Baseline Characteristics between the Study Groups (n=60)

Note: Chi-square test & Independent sample t-test, Observed difference was statistically insignificant

Table 3 demonstrates a significantly lower post-intubation heart rate and MAP in the video laryngoscopy group compared with the direct laryngoscopy group. Mean post-intubation heart rate was 91.30 ± 4.64 beats/min versus 102.53 ± 3.73 beats/min, respectively, while mean post-intubation MAP was 101.73 ± 3.07 mmHg versus 113.57 ± 4.88 mmHg. Both differences were statistically significant (p<0.001).

Table 3: Comparison of Post-Intubation Hemodynamic Parameters between the Study Groups (n=60)

Note: Data are presented as mean ± SD. Independent-samples t-test was used. *Statistically significant at p≤0.05.

Table 4 shows that post-intubation heart rate remained significantly lower with video laryngoscopy across all examined categories, including age, gender, BMI, ASA status, baseline heart rate, and baseline MAP. Mean heart rate in the video laryngoscopy group ranged from 90.13 to 92.47 beats/min, compared with 102.15 to 102.82 beats/min in the direct laryngoscopy group. All subgroup comparisons were statistically significant (p≤0.001).

Table 4: Comparison of Post-Intubation Heart Rate between the Study Groups according to Different Categories (n=60)

Note: Data are presented as mean ± SD. Independent-samples t-test was used. *Statistically significant at p≤0.05.

Table 5 demonstrates consistently lower post-intubation MAP with video laryngoscopy across all evaluated subgroups. Mean MAP ranged from 101.14 to 102.13 mmHg in the video laryngoscopy group compared with 112.81 to 115.17 mmHg in the direct laryngoscopy group. The difference remained statistically significant across all categories, with all p-values <0.001.

Table 5: Comparison of Post-Intubation Mean Arterial Pressure between the Study Groups according to Different Categories (n=60)

Note: Data are presented as mean ± SD. Independent-samples t-test was used. *Statistically significant at p≤0.05.

The present randomized controlled trial showed that the hemodynamic response to ETI is significantly less with video laryngoscopy than with conventional direct laryngoscopy. The mean HR after intubation was 91.30 ± 4.64 beats/min in the video-laryngoscopy group, and 102.53 ± 3.73 beats/min in the direct-laryngoscopy group (p<0.001). Similarly, mean post-intubation MAP was 101.73 ± 3.07 mmHg versus 113.57 ± 4.88 mmHg, respectively (p<0.001). These results suggested that the cardiovascular response during the procedure of airway instrumentation was significantly reduced with video laryngoscopy [14]. The physiological explanation is in line with less need of oral, pharyngeal and laryngeal axis alignment and maybe less thrust applied to the airway structures when looking at them and inserting the tube. The decrease in heart rate we saw in our study compare well with Altun et al. (2018), who were able to compare the Macintosh, McCoy, C-MAC and McGrath laryngoscopes in a prospective study of 160 patients. Their study showed that the conventional Macintosh laryngoscope resulted in a greater increase in heart rate after intubation, while the McGrath video laryngoscope caused less fluctuation in the heart rate and systolic blood pressure. Our study showed a post intubation heart rate of 91.30 ± 4.64 beats/min under video laryngoscopy, whereas it was 102.53 ± 3.73 beats/min under direct laryngoscopy. The results, therefore, support the previous report that video-based visualization can diminish the magnitude of sympathetic stimulation of the cardiovascular system that occurs with laryngoscopy [15]. Our MAP results also show a clinically meaningful difference between techniques! Video laryngoscopy (101.73 ± 3.07 mmHg) resulted in a lower MAP than direct laryngoscopy (113.57 ± 4.88 mmHg) (p<0.001). This finding is similar to the recent randomized controlled trial of Ghattas et al. (2025) in which 80 ASA I–II elective surgery patients were randomly assigned to video or direct laryngoscopy. The mean blood pressure and heart rate with VIDEO LARINGOSCOPY were significantly reduced compared to direct laryngoscopy (respectively 78.83 vs. 90.50 mmHg; 84.78 vs. 92.13 beats/min). While their absolute values were lower, the direction and statistical significance of the differences were remarkably the same [16]. The consistency of our findings with previous evidence is also confirmed by the wider literature on the comparison of video and direct laryngoscopy. In a meta-analysis of 11 randomized trials with 1,196 patients, Su et al (2011) found that video laryngoscopy is a useful alternative to direct laryngoscopy and is especially beneficial in managing the difficult airway. While the meta-analysis primarily focused on outcomes of intubation rather than HR and MAP endpoints investigated in this study, the results align with the technical arguments for the use of video laryngoscopy. The remarkable decreases in both our post-intubation HR and MAP (91.30 vs. 102.53 beats/min; 101.73 vs. 113.57 mmHg) raises the possibility that these technical benefits could lead to less cardiovascular stimulation [17]. Importantly, the hemodynamic benefit seen in our study did not change when we stratified. All of these comparisons were significant in regard to post-intubation heart rate being significantly lower in the VLS group across age, sex, BMI, ASA class, baseline heart rate, and baseline MAP groups. Similarly, post-intubation MAP was significantly lower in each of the subgroups studied. This uniformity enhances the main comparison, as differences were not limited to any particular demographic and physiological sub-group. The results are similar to those of Altun et al. (2018) who also reported less hemodynamic fluctuation when using a video laryngoscope, but did not confirm that the magnitude of the response might be different depending on the design of the video laryngoscope [15]. In summary, the present results confirm the feasibility of using video laryngoscopy in situations where cardiac stimulation is to be avoided during routine endotracheal intubation. Of the differences observed, the lower heart rate (+/- 11.23 beats per minute) and lower MAP (+/- 11.84 mmHg) were statistically significant and directionally similar to the evidence that was contemporary with the trial. In the same way, the previous research study found that indirect video laryngoscopy improved the hemodynamics post intubation versus direct laryngoscopy [18] and another study by Altun et al. (2018) showed lesser cardiovascular fluctuation during intubation with McGrath video laryngoscopy. However, the present study included only 60 relatively young (low-risk) patients and the conclusions should be interpreted with care for extrapolating to elderly patients, difficult airways or patients with significant cardiovascular disease [15,18]. STRENGTHS AND LIMITATIONS This study has important strengths, in that it was randomized controlled, and provided a direct comparison of conventional and video laryngoscopy under a set standard anesthetic and intubation protocol. The internal validity of the results was reinforced by applying random allocation, baseline characteristics that were comparable between the two groups, and standardized measurement of heart rate and mean arterial pressure 1 minute after intubation. The study also analyzed the hemodynamic response in the following clinically relevant demographical and clinical subgroups: age, gender, BMI, ASA status, baseline heart rate, and baseline MAP. There are, however, a number of restrictions that need to be taken into account. The findings may be limited to the relatively few patients (60) and single site of study. The results may not be applicable to higher-risk populations because the participants were young adults who had relatively little anesthetic risk and excluded patients with important cardiovascular disease, hypertension, obesity and other risk factors. Furthermore, only immediate response 1 min after intubation was evaluated and the duration and recovery of the hemodynamic changes were not assessed. Other potentially relevant outcomes that were not assessed in the study included intubation time, number of intubation attempts, airway difficulty, and postoperative complications.

The present study demonstrates that immediately after endotracheal intubation, the hemodynamic response in patients undergoing video laryngoscopy is significantly less than compared to conventional direct laryngoscopy. Video laryngoscopy (VL) is associated with a decrease in heart rate and mean arterial pressure after intubation, indicating less cardiovascular stimulation during airway manipulation with VL. It has been consistent within the evaluated demographic and baseline clinical subgroups, further supporting the potential hemodynamic benefit of video laryngoscopy. Thus, video laryngoscopy may be a useful alternative to conventional laryngoscopy in situations where a reduction in cardiovascular responses during ETT intubation is desired. Further studies on larger, more diverse populations should be done to confirm these findings and validate their applicability in patients with higher anesthetic and cardiovascular risk.