RESUMEN

BACKGROUND: Postoperative orthostatic intolerance can limit mobilization after hip and knee arthroplasty. The literature is lacking on the incidence and risk factors associated with orthostatic intolerance after elective arthroplasty. METHODS: A retrospective case-control study of primary total hip, total knee, and unicompartmental knee arthroplasty patients was conducted. Patients with orthostatic events were identified, and potential demographic and perioperative risk factors were recorded. Orthostatic intolerance was defined as postoperative syncope, lightheadedness, or dizziness, limiting ambulation and/or requiring medical treatment. Statistical analysis was completed using Pearson's chi-square test for categorical data and t-tests for continuous data. Binary logistic regression was performed. RESULTS: A total of 500 consecutive patients were included. The overall incidence of orthostatic intolerance was 18%; 25% in total hip arthroplasty (THA) and 11% in total knee arthroplasty. On univariate analysis, significant risk factors for developing postoperative orthostatic intolerance include older age, female gender, THA surgery, lower American Society of Anesthesiologists class, absence of recreational drug use, lower estimated blood volume, lower preoperative diastolic blood pressure, spinal with monitored anesthesia care (MAC), posterior approach for THA, bupivacaine use in spinal, percent of blood loss, postoperative oxycodone or tramadol use, higher postoperative intravenous fluid volume, and lower postoperative hemoglobin. Multivariate analysis demonstrated persistent significance of female gender, THA surgery, spinal with MAC, bupivacaine use in spinal, and more intravenous fluid administered postoperatively. CONCLUSION: Orthostatic intolerance affects a significant number of arthroplasty patients. Awareness of risk factors and modification of perioperative variables linked to orthostatic intolerance may assist the surgeon in choosing the appropriate surgical setting, educating patients, and improving early postoperative recovery.

Asunto(s)

Artroplastia de Reemplazo de Cadera , Artroplastia de Reemplazo de Rodilla , Intolerancia Ortostática , Artroplastia de Reemplazo de Cadera/efectos adversos , Artroplastia de Reemplazo de Rodilla/efectos adversos , Bupivacaína , Estudios de Casos y Controles , Mareo/complicaciones , Femenino , Humanos , Incidencia , Intolerancia Ortostática/complicaciones , Intolerancia Ortostática/epidemiología , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/etiología , Estudios Retrospectivos , Factores de Riesgo

RESUMEN

In terrestrial environments, upright spatial orientation can dramatically influence animals' hemodynamics. Generally, large and elongated species are particularly sensitive to such influence due to the greater extent of their vascular beds being verticalized, favoring the establishment of blood columns in their bodies along with caudal blood pooling, and thus jeopardizing blood circulation through a cascade effect of reductions in venous return, cardiac filling, stroke volume, cardiac output, and arterial blood pressure. This hypotension triggers an orthostatic-(baroreflex)-tachycardia to normalize arterial pressure, and despite the extensive observation of this heart rate (fH ) adjustment in experiments on orthostasis, little is known about its mediation and importance in ectothermic vertebrates. In addition, most of the knowledge on this subject comes from studies on snakes. Thus, our objective was to expand the knowledge on this issue by investigating it in an arboreal lizard (Iguana iguana). To do so, we analyzed fH , cardiac autonomic tones, and fH variability in horizontalized and tilted iguanas (0°, 30°. and 60°) before and after muscarinic blockade with atropine and double autonomic blockade with atropine and propranolol. The results revealed that I. Iguana exhibits significant orthostatic-tachycardia only at 60o inclinations-a condition that is primarily elicited by a withdrawal of vagal drive. Also, as in humans, increases in low-frequency fH oscillations and decreases in high-frequency fH oscillations were observed along with orthostatic-tachycardia, suggesting that the mediation of this fH adjustment may be evolutionarily conserved in vertebrates.