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Tuesday, October 18, 2016

ANESTHETIC CONCERNS IN TRANS SPHENOIDAL PITUITARY SURGERIES


๐Ÿจ Pituitary tumours can be hypo or hyper secretory : so they may exhibit Cushingoid status or cortisol deficiency. Accordingly the anesthetist has to look for diseases which are associated with these conditions


๐Ÿจ During the Pre Anesthetic Check up (PAC), we should screen for the presence of factors affecting airway management, like


✔️ Macroglossia

✔️ Soft tissue hypertrophy

✔️Obstructive Sleep Apnea (OSA)


And also for other associations like


✔️ DM

✔️ Systemic Hypertension 

✔️ Ischemic Heart Disease

✔️ Heart failure

✔️ Pulmonary Hypertension 


 ๐Ÿจ If there is cortisol deficiency ( can be diagnosed by short synacthen test) glucocorticoid supplementation should be continued peri-operatively.


๐Ÿจ The trans nasal trans sphenoidal approach offers better visibility and lesser incidence of postoperative Diabetes Insipidus (DI). NB: Both DI and SIADH can occur as postoperative complications; but incidence of DI is much higher (upto 50%) compared to that of SIADH.


๐ŸจTrans nasal surgery requires oro-tracheal intubation, insertion of a throat pack to prevent blood going to trachea and stomach and infiltration of the nasal mucosa with local anesthetic and vasopressor ( by surgeon )


๐Ÿจ Establishment of an arterial line will help to intervene promptly during hemodynamic fluctuations that happens with infiltration or intense surgical stimulation 


๐Ÿจ Surgeon may request various 'helps' from the anesthesiologist to make the suprasellar part of the tumor prolapse down into the sella, like:


✔️ Insertion of a lumbar drain and letting out of CSF

✔️ Maintenance of hypercapnea (upto 60 mm of Hg)

✔️ Fluid administration


๐Ÿจ As the patient is positioned with upper part of trunk and head elevated, there is chance for venous air embolism


๐Ÿจ Use of short acting drugs facilitate a rapid and smooth emergence which will help in neurological assessment 


๐Ÿจ Presence of blood in pharynx, nasal packs and preexisting OSA, pose additional problems in managing the airway


๐Ÿจ We can't apply a nasal CPAP mask in such cases as it can cause pneumocephalus, meningitis and air embolism


Reference: Lim M, Williams D, Maartens N. Anaesthesia for pituitary surgery. J Clin Neurosci. 2006; 13(4): 413–418.

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