A Correlational Study to Analyze the Effect of Decrease in Mean Arterial Pressure on Cerebral Oxygen Saturation in Hypertensive Patients during Hypotensive Anesthesia for Transsphenoidal Surgery

Abstract

Background

Controlled hypotension is employed for transsphenoidal surgeries (TSS) to provide a bloodless surgical field carries the potential risk of cerebral hypoperfusion and neurological injury. Pituitary adenoma may present with a high incidence of hypertension due to associated acromegaly and Cushing's disease. The risk of cerebral hypoperfusion increases with a decrease in blood pressure in chronic hypertensive patients due to a rightward shift of the autoregulation curve. This observational study aimed to correlate the changes in cerebral oxygenation (ScO₂) with reduction in mean arterial pressure (MAP) in hypertensive patients undergoing TSS to determine the safety limit of permissive hypotension.

Materials and Methods

Thirty hypertensive patients undergoing transsphenoidal pituitary surgery under hypotension anesthesia (targeted MAP 60–70 mm Hg) were included. Calibrated near-infrared spectroscopy was used to record continuous ScO₂. A decrease in the absolute value of ScO₂ <50 or ≥20% drop from baseline was considered significant. Patients were monitored after surgery for hemodynamic instability, cognitive dysfunction, and any neurological complications.

Results

Eleven out of 30 patients showed a significant drop in ScO_2. A decrease in MAP < 70 mm Hg or more than 30% from baseline was associated with a significant reduction in ScO₂. A fair positive correlation between decrease in MAP and drop in ScO₂ (rho = 0.6, p < 0.001) was observed. The duration of hypertension and ventricular hypertrophy was also associated with a decrease in ScO₂. Postoperative cognitive score was low on day 1 after surgery in patients having deceased ScO₂ (p = 0.045).

Conclusion

Our study showed that ScO₂ monitoring can play a pivotal role in managing MAP during hypotensive anesthesia. It can provide an early warning sign of decreased ScO₂, enabling rapid intervention to prevent postoperative neurological deficit.

Keywords

cerebral hypoxia - chronic hypertension - cognitive dysfunction - hypotensive anesthesia - near-infrared spectroscopy - pituitary surgery

Publikationsverlauf

Artikel online veröffentlicht:
29. April 2025

• References

• 1 Byun YH, Kang H, Kim YH. Advances in pituitary surgery. Endocrinol Metab (Seoul) 2022; 37 (04) 608-616
• 2 Appleby I, John R, Hirsch N. Pituitary disease and anaesthesia. Anaesth Intensive Care Med 2020; 21: 312-316
• 3 Bondanelli M, Ambrosio MR, degli Uberti EC. Pathogenesis and prevalence of hypertension in acromegaly. Pituitary 2001; 4 (04) 239-249
• 4 Hanson M, Li H, Geer E, Karimi S, Tabar V, Cohen MA. Perioperative management of endoscopic transsphenoidal pituitary surgery. World J Otorhinolaryngol Head Neck Surg 2020; 6 (02) 84-93
• 5 Rhodes K, John R, Luoma A. Pituitary disease and anaesthesia. Anaesth Intensive Care Med 2023; 24: 348-352
• 6 Soghomonyan S, Stoicea N, Sandhu GS, Pasternak JJ, Bergese SD. The role of permissive and induced hypotension in current neuroanesthesia practice. Front Surg 2017; 4: 1
• 7 Yu Q, Qi J, Wang Y. Intraoperative hypotension and neurological outcomes. Curr Opin Anaesthesiol 2020; 33 (05) 646-650
• 8 Feng X, Hu J, Hua F, Zhang J, Zhang L, Xu G. The correlation of intraoperative hypotension and postoperative cognitive impairment: a meta-analysis of randomized controlled trials. BMC Anesthesiol 2020; 20 (01) 193
• 9 Strandgaard S. Autoregulation of cerebral blood flow in hypertensive patients. The modifying influence of prolonged antihypertensive treatment on the tolerance to acute, drug-induced hypotension. Circulation 1976; 53 (04) 720-727
• 10 Shekhar S, Liu R, Travis OK, Roman RJ, Fan F. Cerebral autoregulation hypertension and ischemic stroke: a mini review. J Pharm Sci Exp Pharmacol 2017; 2017 (01) 21-27
• 11 Murkin JM, Arango M. Near-infrared spectroscopy as an index of brain and tissue oxygenation. Br J Anaesth 2009; 103 (Suppl. 01) i3-i13
• 12 Shear T, Tobias JD. Cerebral oxygenation monitoring using near infrared spectroscopy during controlled hypotension. Paediatr Anaesth 2005; 15 (06) 504-508
• 13 Folstein MF, Folstein SE, McHugh PR. “Mini-mental state”. A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 1975; 12 (03) 189-198
• 14 Boezaart AP, van der Merwe J, Coetzee A. Comparison of sodium nitroprusside- and esmolol-induced controlled hypotension for functional endoscopic sinus surgery. Can J Anaesth 1995; 42 (5 Pt 1): 373-376
• 15 Rahman NIA, Fouad EA, Ahmed A, Youness AR, Wahib M. Efficacy of different dexmedetomidine regimens in producing controlled hypotensive anesthesia during functional endoscopic sinus surgery. Egypt J Anaesth 2014; 30: 339-345
• 16 Sahu BP, Nayak LK, Mohapatra PS, Mishra K. Induced hypotension in functional endoscopic sinus surgery: a comparative study of dexmedetomidine and esmolol. Cureus 2021; 13 (05) e15069
• 17 Hallén T, Olsson DS, Hammarstrand C. et al. Circulating brain injury biomarkers increase after endoscopic surgery for pituitary tumors. J Clin Neurosci 2021; 89: 113-121
• 18 Thorsson M, Hallén T, Olsson DS. et al. Hypotension during transsphenoidal pituitary surgery associated with increase in plasma levels of brain injury markers. Acta Anaesthesiol Scand 2023; 67 (10) 1363-1372
• 19 McLeod AD, Igielman F, Elwell C, Cope M, Smith M. Measuring cerebral oxygenation during normobaric hyperoxia: a comparison of tissue microprobes, near-infrared spectroscopy, and jugular venous oximetry in head injury. Anesth Analg 2003; 97 (03) 851-856
• 20 Farzanegan B, Eraghi MG, Abdollahi S. et al. Evaluation of cerebral oxygen saturation during hypotensive anesthesia in functional endoscopic sinus surgery. J Anaesthesiol Clin Pharmacol 2018; 34 (04) 503-506
• 21 Park S-H, Do S-H, Kim C-S. et al. Controlling deliberate hypotension in hypertensive patients undergoing spinal surgery: a comparison between remifentanil and sodium nitroprusside. Anesth Pain Med 2010; 5: 38-44
• 22 Ha TN, van Renen RG, Ludbrook GL, Valentine R, Ou J, Wormald PJ. The relationship between hypotension, cerebral flow, and the surgical field during endoscopic sinus surgery. Laryngoscope 2014; 124 (10) 2224-2230
• 23 Trafidło T, Gaszyński T, Gaszyński W, Nowakowska-Domagała K. Intraoperative monitoring of cerebral NIRS oximetry leads to better postoperative cognitive performance: a pilot study. Int J Surg 2015; 16 (Pt A): 23-30