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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.

The effect of age on the haemodynamic response to tracheal intubation was studied. Ninety ASA 1 or 2 patients were divided into three groups of 30 each based on age; ie., young (18-25 years), middle-aged (40-50 years) and elderly (65-80 years). The haemodynamic response after tracheal intubation was observed as percentage change in heart rate and blood pressure compared to the baseline. Inter-group comparison was also done at different time points. The greatest percentage change in the systolic arterial pressure after tracheal tube insertion was seen in the elderly group (15%). The increase in systolic arterial pressure was significantly less in theyounggroup compared with the two older groups at one, two, three and four minutes post-intubation. The greatest percentage increase in the diastolic blood pressure compared to the baseline was seen in the middle aged group (24%). The elderly and young patients showed a significant difference in the diastolic blood pressure response only at one minute post-intubation. The heart rate response was greatest in the middle-aged patients (40%) and least in the elderly (16%). These differences may have clinical significance and should be considered in assessing and performing research into the haemodynamic response to intubation.