Increased body mass index and ASA physical status IV are risk factors for block failure in ambulatory surgery — an analysis of 9,342 blocks

Abstract

P Pu ur rp po os se e: : Regional anesthesia can be the technique of choice for selected ambulatory surgery procedures, but in spite of its benefits, it has an inherent failure rate even in experienced hands. We examine the efficacy and factors associated with failure of ambulatory regional anesthesia techniques. M Me et th ho od ds s: :This study included 9,342 blocks performed on 7,160 patients at the Duke University Ambulatory Surgery Center. Blocks were classified as interscalene, supraclavicular, axillary, lumbar plexus, femoral, sciatic, ankle, paravertebral, spinal, and other (frequency less than 100). A block was considered surgical if a single attempt at placing the block resulted in a complete sensory, motor, and sympathetic nerve block. Multiple logistic regression analyses were used to assess the risk-adjusted association between patient characteristics and block failure.R Re es su ul lt ts s: : Paravertebral blocks and those considered in the "other" category had significantly higher failure rates (P < 0.001), while spinal and lumbar plexus blocks had lower than average rates of failure (P < 0.001 and P = 0.03, respectively).In multiple logistic regression analyses excluding paravertebral blocks, body mass index (BMI) scores greater than 25 (P values: BMI 25-29: < 0.001; BMI 30-34: P < 0.001; BMI 35: P < 0.001) and ASA physical status IV (P < 0.001) were significantly associated with higher block failure rates.C Co on nc cl lu us si io on n: : High BMI and ASA IV are independent risk factors for block failure in ambulatory surgery patients. (P < 0,001 et P = 0,03, respectivement Objectif : L'anesthésie régionale peut être la technique de choix pour certaines interventions chirurgicales ambulatoires, mais en dépit de ses avantages, elle présente un taux d'échec inhérent même entre des mains expertes. Nous vérifions l'efficacité des techniques d'anesthésie régionale ambulatoire et les facteurs associés à son échec. Méthode

Peripheral nerve blocks give greater hemodynamic stability than general anesthesia for ASA III patients undergoing outpatient knee arthroscopy

“…Although the success rate of regional anesthesia is reported to decrease with increasing BMI and higher ASA classification [17] this did not appear to be a problem in our patients who were obese and had an ASA classification of III or higher.…”

Perioperative management of the severely obese patient: a selective pathophysiological review

“…106 These techniques can obviously be more anatomically challenging in the obese patient, and such patients also have less tolerance for potential adverse effects, such as excessive spread of local anesthetic leading to higher than expected spinal or epidural blocks. Given the difficulty with landmark identification, there has been a great deal of interest in ultrasound-guided RA.…”

Obezite Hastalarında Anestezi Yönetimi

“…Üst ekstremite ve alt ekstremite periferik blok uygulaması da obez hastalarda çeşitli güçlüklerle birliktedir. Ultrason kullanımının blok başarı şansını arttırdığı belirtilmektedir 39 . Ayrıca spinal anestezide giriş noktasının belirlenmesinde ultrasonun güvenilir bir rehber olabileceği belirtilmiştir 40 .…”