Abstract
Background: The most important prerequisites for neurosurgeries are brain relaxation, need of
stable haemodynamics with less fluctuation in intracranial pressure and speedy recovery
from anaesthesia. Endotracheal intubation is the major stressful stimuli that can
elicit a marked pressor response. Various drugs have been used to attenuate these
reflexes. Dexmedetomidine, a highly selective alpha 2-adrenoceptor agonist, have neuroprotective,
cardioprotective, and sedative effects so it is potentially useful during neuroanaesthesia.
This is a prospective randomised control trial carried out to see whether administration
of Dexmedetomidine prior to intubation can attenuate the various haemodynamic responses,
intraocular pressure (IOP) and the requirement of induction dose of propofol in control
and study group. Materials and Methods: Fifty patients (ASA grade 1, 2) scheduled for intracranial tumour surgeries were
divided into two groups (25 each). Group D received Dexmedetomidine 0.8 μg/kg i.v.
over 10 mins and group C received 20 ml saline. Anaesthesia induced with Propofol,
dose adjusted using bispectral index monitor. The groups were compared with IOP, Heart
rate (HR), Mean arterial pressure (MAP), and dose of Propofol required for induction.
Results: Groups were well matched for their demographic data and pre-operative. IOP in both
the eyes decreases significantly after premedication and remained below baseline even
after 10th min of intubation in group D while in Group C; it increased significantly after intubation
and remained above baseline. The difference between groups was also statistically
significant. HR and MAP decreased significantly in patients of group D compared to
group C ( P< 0.05). Patients were more haemodynamicaly stable at all time points after premedication
in group D ( P< 0.05). Propofol requirements for induction was lesser in group D (P < 0.05). Bradycardia and hypotension incidences were higher in group D. Conclusion: Dexmedetomidine premedication decreases the sympathoadrenal effect on IOP and haemodynamic
parameters during laryngoscopy/intubation and decreases the requirement of propofol
for induction of general anaesthesia.
Keywords
α
2-agonists - dexmedetomidine - general anaesthesia - intraocular pressure - intracranial
tumour surgery - haemodynamic response - tracheal intubation
