Intracranial pressure changes during Valsalva manoeuvre in patients undergoing a neuroendoscopic procedure.

BACKGROUND

The Valsalva manoeuvre results in an increase in intrathoracic pressure which alters the systemic and cerebral circulations significantly. We decided to record changes in the intracranial pressure and cerebral perfusion pressure resulting from a Valsalva manoeuvre in anaesthetised patients.

METHODS

11 patients of either gender submitted to surgical neuroendoscopic procedures were studied. Standard general anaesthesia was maintained for the procedure in all the patients. Passive Valsalva manoeuvres were carried out by squeezing the bag of the closed breathing circuit to maintain an airway pressure of 20 cm H2O above peak inspiratory airway pressure for 10 seconds. The variables heart rate, mean arterial pressure, intracranial pressure and cerebral perfusion pressure were noted. The variables were recorded again after the surgical correction. All cardiovascular and cerebrovascular variables were compared using the Wilcoxon sign-rank test. We considered a value of p less than 0.05 to be statistically significant.

RESULTS

The median age of the 11 patients was 22 years (range: 15-43) and median weight was 50 kg (range: 30-78). On comparing the variables during the two Valsalva manoeuvres, we found significant changes in HR, ICP and CPP after the surgical correction. No complications were encountered in any of the patients.

CONCLUSION

There was a significant reduction in cerebral perfusion pressure during the Valsalva manoeuvre in both stages. This was a result of change in either the intracranial pressure or the mean arterial pressure. Although our patients did not suffer a clinically significant reduction in cerebral perfusion pressure and so had an uneventful recovery, the effect of Valsalva manoeuvre on cerebral perfusion pressure cannot be denied. The marked haemodynamic changes clearly warrant a cautious use of this manoeuvre in neurosurgical practice.