Effect of controlled hyperventilation on the pressor response to laryngoscopy and tracheal intubation.

Pressor response to laryngoscopy and tracheal intubation includes rises in blood pressure and heart rate. This response may be harmful in the presence of cerebral or myocardial diseases. Although different preventive measures have been developed the choice of the agent or method has not been defined clearly. Hypocapnia is commonly used in anesthesia practice for different indications. It depresses the cardiovascular system and lowers the cardiac output. This study investigated the effect of controlled hyperventilation on the pressor response to laryngoscopy and tracheal intubation in three groups of healthy adult patients with different levels of end tidal CO2. The blood pressure and heart rate were recorded during induction of general anesthesia before and after laryngoscopy and tracheal intubation. The pressor responses to laryngoscopy and tracheal intubation in hypocapnic and normocapnic groups were comparable. Moderate degrees of controlled hyperventilation caused relatively more fluctuation in blood pressure during induction of anesthesia. It can be concluded that controlled hyperventilation has no beneficial effect upon the pressor response to laryngoscopy and tracheal intubation.