Sir,Hemodynamic disturbances may occur in neurosurgical patients and mostly related to raised intracranial pressure or various nerve reflexes.[1] Here we have reported a case of severe hemodynamic disturbances in a patient undergoing excision of suprasellar meningioma and its cause.A 45-year-old female patient was admitted to the department of neurosurgery with diminution of vision of right eye since 4 months. Magnetic resonance imaging revealed 2 × 2 cm homogenous mass on suprasellar region. The patient was diagnosed as a case of suprasellar meningioma and posted for bifrontal craniotomy with tumor excision in supine position. All the preoperative investigations, including electrocardiogram and X-ray chest, were normal. On the day of the surgery, the patient was premedicated with 0.2 mg glycopyrrolate intramuscularly an hour before the surgery. Routine monitors were attached. Baseline heart rate was 78 beats/ min and blood pressure was 130/80 mmHg. General anesthesia was induced with fentanyl 2 μg/kg, thiopentone sodium 4 mg/ kg and tracheal intubation facilitated with rocuronium 1 mg/ kg. Trachea was intubated using 7.5 mm cuffed portex endotracheal tube. Anesthesia was maintained with sevoflurane in oxygen nitrous oxide mixture (40:60) and intermittent boluses of fentanyl and vecuronium as and when required. Dexmedetomidine was also started just before the incision (1 μg/kg bolus over 10 min followed by 0.4–0.5 μg/kg/min infusion). Intraoperative invasive monitoring, that is, central venous pressure and arterial blood pressure, was done using right subclavian vein and left dorasalis pedis artery, respectively. The patient was maintained on a mean arterial pressure of 65–70 mmHg. During retrochiasmatic dissection, sudden severe bradycardia (30 beats/min) with hypotension (mean arterial pressure 50 mmHg) was observed. The surgeon was immediately informed. After removal of the stimulus, heart rate, and blood pressure reverted to normal. These transient hemodynamic disturbances occur twice. No pharmacologic intervention was done. After excision, rest of the intraoperative course was uneventful. The patient was shifted to intensive care unit for elective ventilation. Next day, trachea was extubated when the patient was fully conscious and followed commands.
DISCUSSION
Hemodynamic disturbances in neurosurgical patients frequently occur due to raised intracranial pressure, trigeminal–cardiac reflex, vagal stimulations, and stimulation of floor of fourth ventricle. Hypothalamic stimulation is responsible to produce wide arrays of cardiovascular system dysfunctions. As the hypothalamus is in the close vicinity in the suprasellar compartment, it is likely to produce such an event in this patient. A similar hemodynamic event has been reported during hydrogen peroxide irrigation in craniopharyngioma surgery.[2] The anterior hypothalamus participates in baroreflex regulation of heart rate by altering parasympathetic tone but without affecting cardiac sympathetic nerve activity.[3] So the anterior hypothalamus stimulus probably contributed to severe bradycardia and hypotension in our patient.In conclusion, any surgery in the suprasellar region may produce similar symptoms due to anterior hypothalamus handling, but immediate removal of such stimuli generally abort such hemodynamic disturbances and usually no active pharmacologic intervention is needed.