Pathophysiologic Hemodynamics After Primary Unilateral Total Hip Arthroplasty in Patients Receiving ACEIs and ARBs

Pathophysiologic Hemodynamics After Primary Unilateral Total Hip Arthroplasty in Patients Receiving Angiotensin-Converting Enzyme Inhibitors (ACEIs) and Angiotensin II Receptor Blockers (ARBs)

Incidence and pathophysiologic hemodynamics of postoperative orthostatic intolerance and orthostatic hypotension in patients receiving antihypertensives

Early postoperative mobilization is essential for rapid functional recovery after surgery and it is considered a cornerstone in the so-called fast track multimodal perioperative approach, which includes early ambulation, oral nutrition, multimodal opioid-sparing analgesia and optimized fluid therapy. This strategy has improved patient outcome after surgery and reduced hospital length of stay. Immobilization after surgery is associated with increased risk of complications including venous thromboembolism (deep venous thrombosis, pulmonary embolism), muscle wasting, pneumonia and atelectasis, thereby impending convalescence.

However, early postoperative mobilization can be delayed due to failed orthostatic cardiovascular regulation, resulting in postoperative orthostatic hypotension (OH), defined as a decrease in systolic blood pressure > 20 mmHg or diastolic blood pressure > 10 mmHg or postoperative orthostatic intolerance (OI), characterized by dizziness, nausea, vomiting, visual disturbances or syncope.

Previous studies investigating the incidence and pathophysiology of postoperative OI and OH included mixed patient populations. Hitherto no studies have been performed looking into the incidence and pathophysiologic hemodynamics of postoperative OI and OH specifically in patients receiving angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs), antihypertensive agents with potential effects on cardiovascular compensatory functions.

The current study aims therefore to estimate the incidence and gain knowledge on pathophysiological hemodynamics of postoperative OI and OH in patients receiving ACEIs and ARBs.

Inclusion Criteria:

• Patients undergoing primary unilateral total hip arthroplasty (THA) in spinal anaesthesia in standardized fast-track setting
• Habitual use of angiontensin-Converting Enzyme Inhibitors (ACEIs) and/or angiotensin 2 receptor blockers (ARBs) on any indication
• Patients > 18
• Patients that understand and speak Danish
• Patients that have provided written informed consent

Exclusion Criteria:

• Alcohol abuse
• Any type of substance abuse
• Chronic pain treated by habitual use of opioids
• Habitual use of anxiolytic, antidepressant and/or antipsychotic drugs
• History of cerebral apoplexy or transitory cerebral ischemia
• History of previous orthostatic intolerance or hypotension
• History of diabetes mellitus
• History of following diseases of the autonomic nervous system: Parkinson disease, multiple sclerosis, multiple system atrophy, autonomic neuropathies
• Cognitive dysfunction
• Dementia
• American Society of Anesthesiologists (ASA) > 3