Oral Midodrine Hydrochloride for Prevention of Orthostatic Hypotension during Early Mobilization after Hip Arthroplasty: A Randomized, Double-blind, Placebo-controlled Trial.
BACKGROUND
Early postoperative mobilization is essential for rapid recovery but may be impaired by orthostatic intolerance (OI) and orthostatic hypotension (OH), which are highly prevalent after major surgery. Pathogenic mechanisms include an insufficient postoperative vasopressor response. The oral α-1 agonist midodrine hydrochloride increases vascular resistance, and the authors hypothesized that midodrine would reduce the prevalence of OH during mobilization 6 h after total hip arthroplasty relative to placebo.


METHODS
This double-blind, randomized trial allocated 120 patients 18 yr or older and scheduled for total hip arthroplasty under spinal anesthesia to either 5 mg midodrine hydrochloride or placebo orally 1 h before mobilization at 6 and 24 h postoperatively. The primary outcome was the prevalence of OH (decrease in systolic or diastolic arterial pressures of > 20 or 10 mmHg, respectively) during mobilization 6 h after surgery. Secondary outcomes were OI and hemodynamic responses to mobilization at 6 and 24 h.


RESULTS
At 6 h, 14 (25%; 95% CI, 14 to 38%) versus 23 (39.7%; 95% CI, 27 to 53%) patients had OH in the midodrine and placebo group, respectively, relative risk 0.63 (0.36 to 1.10; P = 0.095), whereas OI was present in 15 (25.0%; 15 to 38%) versus 22 (37.3%; 25 to 51%) patients, relative risk 0.68 (0.39 to 1.18; P = 0.165). At 24 h, OI and OH prevalence did not differ between groups.


CONCLUSIONS
Preemptive use of oral 5 mg midodrine did not significantly reduce the prevalence of OH during early postoperative mobilization compared with placebo. However, further studies on dose and timing are warranted since midodrine is effective in chronic OH conditions.
From the Section of Surgical Pathophysiology, The Juliane Marie Center, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark (Ø.J., J.J., T.H.L., H.K.); Coordinating Research Centre, Frederiksberg Hospital, Frederiksberg, Denmark (J.M.); Department of Orthopedic Surgery, Vejle Sygehus, Vejle, Denmark (P.K.-A.); Departments of Orthopedic Surgery (H.H.) and Anesthesia (T.H.L.), Hvidovre Hospital, Hvidovre, Denmark; Department of Orthopedic Surgery, Gentofte Hospital, Hellerup, Denmark (S.S.); and The Lundbeck Centre for Fast-Track Hip and Knee Arthroplasty, Copenhagen, Denmark (Ø.J., T.H.L., H.K.).
Øivind
Ø
Jans
Jesper
J
Mehlsen
Per
P
Kjærsgaard-Andersen
Henrik
H
Husted
Søren
S
Solgaard
Jakob
J
Josiassen
Troels Haxholdt
TH
Lunn
Henrik
H
Kehlet
D000284:Administration, Oral; D058646:Adrenergic alpha-1 Receptor Agonists / Q000008:administration & dosage / Q000627:therapeutic use*; D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D001794:Blood Pressure / Q000187:drug effects; D004311:Double-Blind Method; D004434:Early Ambulation; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007024:Hypotension, Orthostatic / Q000517:prevention & control*; D008297:Male; D008879:Midodrine / Q000008:administration & dosage / Q000627:therapeutic use*; D054971:Orthostatic Intolerance / Q000517:prevention & control; D016896:Treatment Outcome
D058646:Adrenergic alpha-1 Receptor Agonists; D008879:Midodrine