Laryngoscopy and endotracheal intubation is an integral part of general anesthesia. Direct laryngoscopy and passage of endotracheal tube through the larynx is a noxious stimulus, which can provoke untoward response in the cardiovascular, respiratory and other physiological systems. (1) . Significant tachycardia and hypertension can occur with tracheal intubation under light anaesthesia. Hypertension, tachycardia and arrhythmia caused by endotracheal intubation can be deleterious in

patients with poor cardiovascular reserve. The magnitude of hemodynamic response increases with the force and duration of laryngoscopy (DOL) and can also be influenced by prolonged intubation time (10). Because it may lead to rare, but serious complications such as myocardial infarction or brain hemorrhage, Anesthesiologists should be careful to minimize the incidence of hypertension during tracheal intubation. Thus, use of different types of laryngoscope blades can help decreasing these responses

The Macintosh laryngoscope (MCL) has been the “gold standard” device for direct laryngoscopy and tracheal intubation since its invention by Foregger and Foregger in 1940s. Direct laryngoscopy (DL) does not always allow optimal viewing of the glottis, especially in those patients with anatomical characteristics which can make tracheal intubation difficult. (2)

The videolaryngoscope(VLS) (HugeMed, Shenzhen) is a portable device designed to perform indirect laryngoscopy in both routine and difficult airway intubations, in elective or in emergency settings(3). The main advantage is the visualization of the target, as the operator's “eye” is now located at the tip of the blade 2 or 3 cm. The alignment of the oral-pharyngeal-laryngeal axis, crucial to DL, is thus rendered nonessential in VLS. The number of attempts, and consequently the trauma to the airway, is also reduced.

The study was designed with the objective to assess the hemodynamic changes that occur during and after endotracheal intubation with HugeMed video laryngoscope and comparing those changes with conventional laryngoscopy (Macintosh). We are also comparing the time taken to perform the endotracheal intubation in both groups.

Figure 1: Conventional laryngoscopy using a curved Macintosh blade

Figure.2

The VL3 video laryngoscope.

1. 5” high-resolution display;
2. handle with recording button for pictures and videos;
3. Reusable blade with a 66° field angle;
4. 2- megapixel camera with an antifog lens

After receiving approval from the institutional ethics committee and signed informed consent from the study participants, a comparative- cross sectional study based in a hospital was carried out among 70 patients(35 in each groups) who underwent surgical, gynaecological and orthopaedic procedure under general anaesthesia at the Department of Anaesthesiology, Government Medical College, Thrissur, between October 2021 and October 2022.70 patients will be divided into two equal groups –35 of them were intubated using McIntosh laryngoscope while the rest were intubated using Hugemed videolaryngoscope. The time taken to perform endotracheal intubation and changes in hemodynamic parameters during the initial five minutes following intubation were recorded and compared between the 2 groups.

Inclusion Criteria:

Patients of either sex ASA Grade 1&2

Age between 18& 60year

Patients undergoing elective surgeries

Exclusion Criteria:

Patient refusal Pregnant women

Patients undergoing emergency surgery Those with airway abnormalities

Anticipated difficult airway (Mallampati class lll and IV, thyromental distance <6cm , inter-incisor distance <3cm, and cervical instability)

Active smoking Chronic hypertension In addition, the patient in whom laryngoscopy lasted for more than 30sec and if more than one intubation attempt was needed were also excluded.

Statistical Method:

This was the appropriate statistical technique used to meet the study objective. The Quantitative variables like HR, BP (SBP, DBP, MAP) were compared in 2 groups with unpaired T-test. If any non-normal data exists for comparison Mann-Whitney test was used. ‘p’ value less than 0.05 was considered statistically significant.

The study was conducted in the Department of Anaesthesiology, Govt. Medical College Thrissur from October 2021 - October 2022.The study population consisted of 70 patients undergoing elective surgery requiring endotracheal intubation. Patients satisfying the inclusion criteria were included into 2 groups of 35 each. Group A - patients undergoing intubation with Macintosh laryngoscope. Group B

- patients undergoing intubation with Hugemed video laryngoscope. Data were entered in Microsoft Excel Software and analysed using SPSS version 21.The continuous variables like age, weight, heart rate at different time points, blood pressures at different time points were summarized as mean and standard deviation or median depending on distribution. Categorical variable like sex was summarized as frequencies and proportions. Unpaired t-test were used for comparing continuous variables between the groups at different time points. Chi square test or fishers exact test based on cell counts were used for comparing categorical variables between the two groups.

Figure 3: Mean duration of intubation among the study groups (N=70)

The mean time taken for endotracheal intubation in Group A and Group B are 13.343 seconds and 18.543 seconds respectively. There is significant difference between mean time taken for endotracheal intubation in Group A and Group B with a p value of 0.000.

**Group B takes more time for endotracheal intubation than Group A.

Table 1: Comparison of Mean duration of intubation among study groups (N=70)

**This result is significant at 0.05 level of significance. The mean duration of intubation in group A and group B is 13.343 and 18.543 respectively.

Table 2: Patient demography and other details

The mean age of the group A and group B patients were 44.886 and 43.314 respectively.The mean weight of the group A and group B patients were 65.171 and 65.429 respectively.Out of 35 study patients in group A 9 were males and 26 were females. And out of 35 study patients in group B 10 were males and 25 were females.

Figure 4: Line graph showing the mean Heart rate of the patients during the procedure at different points among the study groups. (N=70)

At all points, the heart rate was similar in both groups with p value >0.05.

Table 3: Heart Rate during the procedure at different time points

Figure 5: Systolic blood pressure of the patients during the procedure at different time points

At all points, the systolic blood pressure was similar in both groups with p value >0.05.

Table 4: Systolic blood pressure during the procedure at different time points

Figure 6: Diastolic blood pressure of the patients during the procedure at different time points (N=70)

At all points, the diastolic blood pressure was similar in both groups with p value >0.05.

Table 5: Diastolic blood pressure during the procedure at different time points (N=70)

Figure 7: Mean arterial pressure of the patients during the procedure at different time points (N=70)

At all points, the mean arterial blood pressure was similar in both groups with p value >0.05

Table 6: Mean arterial pressure during the procedure at different time points (N=70)

Laryngoscopy and endotracheal intubation results in sympathetic stimulation that leads to hypertension and tachycardia. Direct laryngoscopy involves stretching the oropharyngeal tissues in an attempt to straighten the angle between the mouth and the glottic opening, and this stretch can cause pain and trigger a stress response (4). Both laryngoscopy and intubation separately result in sympathetic stimulation, but the catecholamine rise with intubation exceeds that with laryngoscopy alone(5) .Various anaesthetic agents, adjuvants and analgesics have been used to blunt the level of stimulation and the stress response to the manipulation and stimulation of airway during laryngoscopy and intubation. Fentanyl, beta adrenergic receptors blockers, and lignocaine have all been used with varying results(6).Newer airway aids have always been a part of the evolution of anaesthetic equipment and have been used either to facilitate laryngoscopy and intubation so as to avoid major sympathetic stimulation or to aid in a scenario of difficult intubation. These airway aids are compared with the current standard practice of using a direct laryngoscopy and endotracheal intubation. The fibreoptic bronchoscope, McCoy laryngoscope, and more recently the style scope have been studied and the haemodynamic changes have been found to be lesser. In this study, 70 ASA PS class 1 and 2 patients who underwent surgical, gynaecological and orthopaedic procedure under general anaesthesia, requiring endotracheal intubation were observed in Government Medical College, Thrissur. The patients were included in group A(Mcintosh) and group B(Hugemed video laryngoscopy) based on the laryngoscope blade used for intubation. The heart rate, blood pressure (systolic, diastolic and mean) were recorded at six specified intervals, namely, T1= baseline, prior to anaesthetic induction; T2= post induction, prior to relaxant administration; T3= post intubation; T4= 1 min after endotracheal intubation; T5= 2 min after endotracheal intubation; T6= 5 min after endotracheal intubation. The time taken to perform endotracheal intubation was also noted in both the groups by which ease of intubation was compared. Hemodynamic parameters like heart rate, systolic blood pressure, diastolic blood pressure and mean arterial pressure at different time points during the procedure were similar in both groups. No statistically significant difference was observed

between hemodynamic responses to laryngoscopy and tracheal intubation with Mcintosh and Hugemed laryngoscopes. However, this finding of ours is in contrast to a study by Altun et al which compared hemodynamic responses to four different laryngoscopes – McGrath, McCoy, Macintosh and C-mac – in patients with normal airway. The study showed that McGrath videolaryngoscope caused fewer hemodynamic fluctuations compared to the other three devices during laryngoscopy and tracheal intubation.(7).However, in studies conducted by Han et al. and Shimoda et al. regarding hemodynamic effect during laryngoscopy with McCoy and Macintosh laryngoscopes there was no significant difference in the hemodynamic response with the two blades.(8).In a study conducted by kamewad et al which included regarding hemodynamic response and ease of intubation during laryngoscopy with conventional and pentax video laryngoscope did not provide any benefit in terms of haemodynamic response to laryngoscopy and intubation in patients. However The duration of laryngoscopy and intubation was significantly longer in group of patients who was intubated with video laryngoscopy when compared to other group patients.(9).From our study, it can be concluded that while comparing Macintosh and Hugemed laryngoscope, there is no definite advantage of one over the other in reducing the stress response to laryngoscopy and intubation. However, the duration of laryngoscopy and intubation was significantly lower in those for whom Mcintosh laryngoscope was used.

The time taken to perform endotracheal intubation and haemodynamic changes associated with intubation were noted in both the groups at different time points. The duration of laryngoscopy and intubation was significantly longer in group B (Hugemed video laryngoscopy) when compared to group A patients (Mcintosh). However, haemodynamic changes were not different between the groups. Video laryngoscopy did not provide any benefit in terms of haemodynamic response to laryngoscopy and intubation in patients.

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