Orthostatic intolerance during early mobilization after fast-track hip arthroplasty.

BACKGROUND Early postoperative mobilization is a cornerstone in fast-track total hip arthroplasty (THA), but postoperative orthostatic intolerance (OI) may delay early recovery or lead to fainting, falls, and prosthesis dislocation or fracture. However, the prevalence and pathophysiology of OI has not been established after THA. This study evaluated the cardiovascular response and tissue oxygenation to mobilization before and after surgery in relation to OI in fast-track THA patients. METHODS OI and the cardiovascular response to standing were evaluated with a standardized mobilization protocol, before, 6, and 24 h after surgery in 26 patients undergoing THA with spinal anaesthesia and an opioid-sparing analgesic regime. Haemoglobin, fluid balance, and opioid use were recorded. Systolic (SAP) and diastolic (DAP) arterial pressure, heart rate (HR), stroke volume (SV), cardiac output (CO), and systemic vascular resistance were measured non-invasively (Nexfin(®)) and cerebral ( ) and muscle tissue oxygenation by non-infrared spectroscopy. RESULTS No patients demonstrated OI before surgery, whereas 11 (42%) and five (19%) patients experienced OI 6 and 24 h after surgery, respectively. OI was associated with decreased orthostatic responses in SAP, DAP, SV, CO, and compared with orthostatic tolerant patients (P<0.05). There was no difference in postoperative haemoglobin concentrations or opioid use between orthostatic intolerant and tolerant patients. CONCLUSIONS Early postoperative OI is common in patients undergoing THA and is associated with an impaired cardiovascular orthostatic response and decreased cerebral oxygenation.