Effect of Laryngoscopy and Tracheal Intubation on Pulse Pressure and Influence of Age on this Response

Abstract

The study objective was to measure the change in pulse pressure associated with laryngoscopy and tracheal intubation and to relate these changes to trends in systolic, diastolic and mean blood pressure. The rationale was that the rise in systolic and diastolic blood pressure may be disproportionate and may result in either increase or decrease in pulse pressure. We also looked at the influence of age on this response. This prospective observational study measured the changes in pulse pressure secondary to laryngoscopy and tracheal intubation in eighty adult surgical patients. Two groups of forty patients each were included, young (group A) 18-25 years and middle-aged (group B) 45-55 years. The patients were ASA Class 1 or 2, of either gender and non-hypertensive. Systolic, diastolic, and mean blood pressure, and heart rate were measured preinduction and 1, 2 and 3 minutes after induction. Thereafter they were measured every minute for five minutes after intubation. Pulse pressure was obtained by subtracting the diastolic from the systolic blood pressure. No pulse pressure change occurred in the young group despite of a significant increase in both systolic and diastolic blood pressures. The middle aged group showed an average rise of +18 mm of Hg in pulse pressure (taken at 1 minute post-intubation) compared to the baseline measurement (P<0.0001). These changes in pulse pressure during anaesthesia may indicate an additional pulsatile stress in vulnerable patients in addition to the changes associated with resistance alone and need to be studied further.