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Table of Contents    
Year : 2014  |  Volume : 62  |  Issue : 4  |  Page : 441-443

Hypoventilation: An aid to the neurosurgeon

1 Department of Anaesthesia, Christian Medical College, Vellore, Tamil Nadu, India
2 Department of Neurological Sciences, Christian Medical College, Vellore, Tamil Nadu, India

Date of Web Publication19-Sep-2014

Correspondence Address:
Karen Ruby Lionel
Department of Anaesthesia, Christian Medical College, Vellore, Tamil Nadu
Karen Ruby Lionel
Department of Anaesthesia, Christian Medical College, Vellore, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0028-3886.141239

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How to cite this article:
Lionel KR, Singh G, Mathew RR, Moorthy RK, Rajshekhar V, Lionel KR, Singh G, Mathew RR, Moorthy RK, Rajshekhar V. Hypoventilation: An aid to the neurosurgeon . Neurol India 2014;62:441-3

How to cite this URL:
Lionel KR, Singh G, Mathew RR, Moorthy RK, Rajshekhar V, Lionel KR, Singh G, Mathew RR, Moorthy RK, Rajshekhar V. Hypoventilation: An aid to the neurosurgeon . Neurol India [serial online] 2014 [cited 2020 Oct 31];62:441-3. Available from:


We report the successful removal of a giant intracranial hydatid cyst in toto by Dowling's hydrodissection technique with hypoventilation being used as an adjunct.

An 8 year old girl with a large right parieto-occipital intra-parenchymal non-enhancing cyst suggestive of hydatid cyst was planned for a right parieto-occipital craniotomy and excision of the cyst [Figure 1]. In the operating room, standard monitoring with an electrocardiography (ECG), pulse oximetry, invasive blood pressure, and end tidal CO 2 (etCO 2 ) was commenced. After adequate preoxygenation, patient was intubated with 6.0 mm ID cuffed ETT. Anesthesia was maintained with isoflurane (MAC 0.8), oxygen, and air. Routine measures to reduce cerebral edema were undertaken- mannitol 1 gm/kg, dexamethasone 0.1 mg/kg, and an etCO 2 of 28 mm Hg were maintained. After craniotomy, the dura was opened with careful separation of the arachnoid overlying the cyst. The lesion was visualized as a grayish white semi-transparent cyst specked with the protoscolices lying just beneath the cyst wall. Using saline irrigation, hydrodissection of the cyst was performed.
Figure 1: T2W axial MRI of the brain showing a large cystic lesion in the right posterior parietal and occipital lobes with signifi cant mass effect

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The etCO 2 was gradually raised to 38 mm Hg by hypoventilation and trendelenburg tilt was given to raise the intracranial pressure (ICP) to aid the delivery of the cyst. With gentle hydrodissection and the gradual rise in ICP, the cyst was delivered out of its cavity in to [Figure 2] and [Figure 3]. Normal ventilation was resumed, and the child was extubated fully awake and shifted to the neurosurgical intensive care unit.
Figure 2: Intraoperative photograph of the translucent cyst after in toto excision

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Figure 3: Empty cyst cavity after removal of the hydatid cyst

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Carbon dioxide is a powerful cerebral vasodilator, thereby raising the ICP. [1] In most neurosurgical patients, it is desirable to reduce ICP and hence mild hyperventilation is used. This case is an exception wherein hypoventilation was initiated after exposure of the lesion.

The resulting rise in arterial carbon dioxide tension causes increased cerebral blood flow, elevated ICP, thereby aiding delivery of the cyst in toto. Intracranial pressure can be raised by various methods such as intrathecal injection of air, intrathecal injection of saline, bilateral jugular venous compression, valsalva maneuver and by controlled hypercapnia. [2],[3],[4] While use of Valsalva maneuvre to raise ICP and facilitate delivery of the hydatid cyst has been described, there is a risk of sudden and uncontrolled increase in ICP resulting in cyst rupture, which increases the chance of recurrence, cerebral vasospasm, and systemic inflammatory response syndrome. [5] A timely and gradual increase in ICP by hypoventilation as described in this case report is one of the adjunctive factors that aided in complete removal [Figure 4] of this intracranial hydatid cyst.
Figure 4: Post-operative plain computed tomography of the brain showing reduction in the mass effect and evidence of total excision of the cyst

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  References Top

1.Madden JA. The effect of carbon dioxide on cerebral arteries. Pharmacol Ther 1993;59:229-50.  Back to cited text no. 1
2.Hardy J. Transsphenoidal hypophysectomy. J Neurosurg 1971;34:582-94.  Back to cited text no. 2
3.Wilson CB, Dempsey LC. Transsphenoidal microsurgical removal of 250 pituitary adenomas. J Neurosurg 1978;48:13-22.  Back to cited text no. 3
4.Spaziante R, de Divitiis E. Forced subarachnoid air in transsphenoidal excision of pituitary tumors (pumping technique). J Neurosurg 1989;71:864-7.  Back to cited text no. 4
5.Salunke P, Patra DP, Mukherjee KK. Delayed cerebral vasospasm and systemic inflammatory response syndrome following intraoperative rupture of cerebral hydatid cyst. Acta Neurochir (Wien) 2014;156:613-4.  Back to cited text no. 5


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]


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