Incidence and pathophysiologic hemodynamics of orthostatic intolerance and orthostatic hypotension in patients undergoing unilateral THA
Early postoperative mobilization is a cornerstone in the so-called fast track multimodal perioperative approach and is essential in preventing postoperative morbidity and reducing hospital length-of-stay. Intact orthostatic blood pressure regulation is essential for early postoperative mobilization. However, early postoperative mobilization can be delayed due to postoperative orthostatic hypotension (POH) defined as a fall in systolic pressure \> 20 mmHg and/or diastolic pressure \> 10 mmHg or due to postoperative orthostatic intolerance (POI), characterized by dizziness, nausea, vomiting, blurred vision or syncope during mobilization. Although these conditions are well-known clinical problems that can delay early mobilization, relatively few data are available on pathophysiological mechanisms and possible treatments. Several prospective studies with standardized mobilization procedures have already established that the incidence of POI and POH after THA is 38-42% at 6 hours after surgery. Previous studies on patients undergoing prostatectomy and THA have also demonstrated that attenuated vasopressor response and a concomitant reduction in cardiac output (CO) and cerebral perfusion during postural changes after surgery contributes to POI and POH. Strategies aiming to reduce the incidence of POI and POH by pain management, vasoconstrictive treatment with alpha-1 receptor agonist, optimized fluid management with goal-directed fluid therapy and reduction of surgical stress-response with pre-operative high-dose glucocorticoid did not solve the problem. The precise pathophysiological mechanisms of POI and POH remain to be elucidated and this is therefore the aim of the current prospective observational study.
Study Type
OBSERVATIONAL
Enrollment
26
Hvidovre Hospital
Copenhagen, Denmark
RECRUITINGIncidence of orthostatic intolerance
Symptoms of orthostatic intolerance: dizziness, nausea, vomiting, blurry vision or syncope during mobilization
Time frame: 6 hours postoperatively
Incidence of orthostatic hypotension
Orthostatic hypotension is defined as a fall in systolic pressure \> 20 mmHg and/or diastolic pressure \> 10 mmHg during mobilization
Time frame: 6 hours postoperatively
Changes in systolic arterial pressure (SAP) during mobilization
Measured in mmHg
Time frame: Preoperatively, 6 and 24 hours postoperatively
Changes in diastolic arterial pressure (DAP) during mobilization
Measured in mmHg
Time frame: Preoperatively, 6 and 24 hours postoperatively
Changes in mean arterial pressure (MAP) during mobilization
Measured in mmHg
Time frame: Preoperatively, 6 and 24 hours postoperatively
Changes in systemic vascular resistance (SVR) during mobilization
Measured in mmHg⋅min⋅mL-1
Time frame: Preoperatively, 6 and 24 hours postoperatively
Changes in cardiac output (CO) during mobilization
Measured in mL/min
Time frame: Preoperatively, 6 and 24 hours postoperatively
Changes in stroke volume (SV) during mobilization
Measured in mL
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Time frame: Preoperatively, 6 and 24 hours postoperatively
Changes in heart rate variability (HRV) during mobilization
Measured in ms
Time frame: Preoperatively, 6 and 24 hours postoperatively
Changes in baroreflex sensitivity (BRS) during mobilization
Measured in ms/mmHg
Time frame: Preoperatively, 6 and 24 hours postoperatively
Changes in peripheral perfusion index (PPI) during mobilization
Measured in arbitrary units (AU)
Time frame: Preoperatively, 6 and 24 hours postoperatively
Changes in cerebral perfusion (ScO2) during mobilization
Measured in %
Time frame: Preoperatively, 6 and 24 hours postoperatively
Changes in muscular perfusion (SmO2) during mobilization
Measured in %
Time frame: Preoperatively, 6 and 24 hours postoperatively
Changes in total blood volume (TBV)
Measured in mL
Time frame: Preoperatively, 6 and 24 hours postoperatively
Changes in erythrocyte volume (ECV)
Measured in mL
Time frame: Preoperatively, 6 and 24 hours postoperatively
Changes in plasma volume (PV)
Measured in mL
Time frame: Preoperatively, 6 and 24 hours postoperatively
Changes in hematocrit
Measured in %
Time frame: Preoperatively, 6 and 24 hours postoperatively
Changes in haemoglobin (Hgb) concentration
Measured in millimoles/L
Time frame: Preoperatively, 6 and 24 hours postoperatively
Changes in C-Reactive Protein
Measured in mg/L
Time frame: Preoperatively, 6 and 24 hours postoperatively