Assessment of stress response due to C-Mac D-blade guided videolaryngoscopic endotracheal intubation and docking of da Vinci surgical robot using perfusion index in patients undergoing transoral robotic oncosurgery.

Abstract

Clinical utility of perfusion index (PI) has entered a new realm as a non-invasive, quantitative index of stress response to endotracheal intubation. Transoral robotic surgery (TORS) involves F-K retractor aided docking of the surgical robot producing haemodynamic and stress responses akin to laryngoscopy. We compared the stress response to videolaryngoscopy with that due to docking of da Vinci surgical robot using PI, heart rate and mean arterial pressure evaluated at specific time points post-laryngoscopy and post-docking. Twenty-six adult patients, scheduled for TORS under general endotracheal anaesthesia were included in this prospective, observational, single-centric cohort study. Statistical analysis included paired samples t-test, dotted box-whisker plots, trendlines and correlograms for comparative analysis of two stressors, laryngoscopy and docking. Baseline PI was 4.14. PI values increased post-midazolam (4.23), 1min (5.69) and 3min (6.25) post anaesthetic-induction, plummeted at laryngoscopy (3.24), remained low at 1min (3.68), 3min (4.69) thereafter, and were highest at 10min (6.17) post-laryngoscopy and predocking (6.84). Docking witnessed a fall in PI (4.1), which remained low at 1min (4.02), 3min (4.31) and 10min (4.79) post-docking. PI was significantly higher at laryngoscopy compared with PI at docking (p = 0.0044). At 1min and 3min post-laryngoscopy and post-docking, respectively, the differences in PI were statistically insignificant. PI at 10min post-laryngoscopy was significantly lower than PI at 10min post-docking (p < 0.0001). As non-invasively quantified by PI, videolaryngoscopic stress response is more intense but shorter-lived versus that due to docking. PI displays a negative correlation with haemodynamic variables. PI at laryngoscopy is a good predictor of PI at docking, enabling pre-emptive measures (fentanyl bolus; deepening of volatile anaesthesia from MAC-maintenance to MAC-intubation) anticipating the docking-induced stress response.Trial registration http://ctri.nic.in ; Identifier: CTRI/2019/11/022091.