Cerebral Oxygenation in Total Hip Arthroplasty Patients (THANIRS)

Cerebral Near-Infrared Spectroscopy and Hypotensive Anesthesia in Patients Undergoing Total Hip Arthroplasty

We plan to investigate the relationship between hypotensive epidural anesthesia for hip arthroplasty and cerebral oxygen saturation.

The relationship between cerebral oxygenation and blood pressure in patients undergoing hypotensive epidural anesthesia has not been completely elucidated. Previous publications have demonstrated a low incidence of post-op cognitive dysfunction in patients undergoing hypotensive epidural anesthesia for total hip replacement (1-3) and that cerebral blood flow velocity is preserved as measured by transcranial Doppler (4). An earlier investigation by Dr. Yadeau demonstrated infrequent cerebral oxygen desaturation in spontaneously breathing patients undergoing shoulder arthroscopy, even in the presence of hypotension (4), but did not investigate outcomes in the cognitive domain or have a control group of patients undergoing surgery with general anesthesia. There has only been one study looking at cerebral oxygenation and hip surgery, which was performed in elderly patients with fractures. It demonstrated that patients with low pre-op regional cerebral oxygen saturation (rSO2) had higher incidence of delirium (5) but many of those patients had surgery under general anesthesia. Given the costs associated with post-op delirium, cognitive dysfunction and stroke (6) and based on the fact that previous publications from this institution have demonstrated both a low incidence of cognitive dysfunction and preservation of cerebral blood flow velocity using this anesthetic technique, we hypothesized that cerebral oxygen desaturation will not occur in this population.

The number of participant's experiencing an intra-operative cerebral oxygen desaturation event. Measured in the number of patients, beginning with the time the patients' enters the operating room and up to 4 hours.

The number of patients who have post-operative delirium, as determined by counting the patients who suffer from this condition. Although recorded at various time points, the total number of participants experiencing post-operative delirium was summed and reported.

The number of patients considered to experience cognitive dysfunction as identified by low scores on the mini-Cog. The Mini-Cog checks for the brain function (or the cognitive impairment) of the participant. The Mini-Cog does this by examining a patient's ability in two areas. This is done via a three-word recall test and the Clock Drawing Test. Three-Word Recall The Clock Drawing Test (CDT) There are five total points a person can score on the Mini-Cog: Give one point for each word that was correctly remembered. (0-3 points) Give two points for a correctly drawn clock, meaning the numbers are in roughly the correct locations and two hands are pointed to the 11 and the 2. The length of the hands does not matter. (0 or 2 points) If a patient scores less than three points, they are counted as experiencing cognitive dysfunction. Although collected across different time points, the total number of patients scoring less than 3 points were summed and reported.

Inclusion Criteria: Patients 18-80 years old undergoing unilateral total hip arthroplasty Hypotensive epidural anesthesia Exclusion Criteria: Contraindication to controlled hypotension and/or neuraxial anesthesia. Severe pulmonary hypertension or pre-op systolic blood pressure reading >150 mm Hg Moderate to severe valvular stenosis. History of stroke, dementia, or post-op delirium Prior OSA diagnosis History of benzodiazepine use (regular use for longer than 3 months) Chronic renal or hepatic disease (renal failure, history of liver failure, cirrhosis) History of alcoholism or heavy alcohol intake (defined as averaging more than 3 drinks per night; recovery is OK) Parkinson's disease Severe chronic pulmonary disease Total anterior hip approach being used Hip resurfacing procedure Non-English Speaking* Questionnaires being used to assess mental status are only validated in English.

Williams-Russo P, Sharrock NE, Mattis S, Szatrowski TP, Charlson ME. Cognitive effects after epidural vs general anesthesia in older adults. A randomized trial. JAMA. 1995 Jul 5;274(1):44-50.

Sharrock NE, Fischer G, Goss S, Flynn E, Go G, Sculco TP, Salvati EA. The early recovery of cognitive function after total-hip replacement under hypotensive epidural anesthesia. Reg Anesth Pain Med. 2005 Mar-Apr;30(2):123-7. doi: 10.1016/j.rapm.2004.12.005.

Rade MC, Yadeau JT, Ford C, Reid MC. Postoperative delirium in elderly patients after elective hip or knee arthroplasty performed under regional anesthesia. HSS J. 2011 Jul;7(2):151-6. doi: 10.1007/s11420-011-9195-2. Epub 2011 Feb 11.

Yadeau JT, Liu SS, Bang H, Shaw PM, Wilfred SE, Shetty T, Gordon M. Cerebral oximetry desaturation during shoulder surgery performed in a sitting position under regional anesthesia. Can J Anaesth. 2011 Nov;58(11):986-92. doi: 10.1007/s12630-011-9574-7. Epub 2011 Aug 25.

Papadopoulos G, Karanikolas M, Liarmakopoulou A, Papathanakos G, Korre M, Beris A. Cerebral oximetry and cognitive dysfunction in elderly patients undergoing surgery for hip fractures: a prospective observational study. Open Orthop J. 2012;6:400-5. doi: 10.2174/1874325001206010400. Epub 2012 Sep 3.

McDaniel M, Brudney C. Postoperative delirium: etiology and management. Curr Opin Crit Care. 2012 Aug;18(4):372-6. doi: 10.1097/MCC.0b013e3283557211.

Murphy GS, Szokol JW, Marymont JH, Greenberg SB, Avram MJ, Vender JS, Vaughn J, Nisman M. Cerebral oxygen desaturation events assessed by near-infrared spectroscopy during shoulder arthroscopy in the beach chair and lateral decubitus positions. Anesth Analg. 2010 Aug;111(2):496-505. doi: 10.1213/ANE.0b013e3181e33bd9. Epub 2010 May 27.