Biochemical markers and haemodynamic changes of stress response after intubation with direct laryngoscopy versus video laryngoscopy versus fiberoptic intubation: A comparative study

Abstract

Laryngoscopy and intubation leads to stimulation of pharyngeal and tracheolaryngeal nociceptors resulting in haemodynamic stress response (HDSR). Stress response is regulated by two primary neuroendocrine systems- the hypothalamus pituitary adrenocortical (HPA) and sympathetic adrenomedullary (SAM) system. Salivary alpha-amylase (SAA) level can be used as an index of the SAM activity, and serum cortisol as an index of HPA activity. This study was aimed to compare three different intubation techniques namely Macintosh laryngoscope, Video laryngoscope and Fiberoptic bronchoscope to observe stress response. This prospective, comparative and observational study was carried out at 120 patients undergoing various elective surgeries under general anaesthesia. Patients were allocated after randomization into three study groups- Group D (Direct laryngoscope), Group V (Video laryngoscope) and Group F (Fiberoptic bronchoscope) with 40 patients in each. Saliva and venous blood samples were collected before inducing the patients and 5-minutes after intubation. Blood pressure, heart rate and saturation were monitored at fixed intervals.A significant difference was observed in the post-intubation values (p=0.0001) of salivary alpha amylase levels by direct laryngoscopy and fiberoptic laryngoscopy, while it was insignificant in video laryngoscopy (p=0.919). Post intubation cortisol level was significantly high in all three groups. However, on group comparison of mean differences of serum cortisol levels, a significant mean difference was seen between D vs V group (p=0.0001), and V vs F group (p=0.0001), while it was not significant in D vs F group (0.157). In addition, changes in mean arterial pressure and heart rate, at 1- and 5-min post- intubation were least in group V. Video laryngoscopy is a safe, and reliable technique. Moreover, it causes lesser stress response to patients in comparison to direct laryngoscopy and fiberoptic groups.