Abstract：
OBJECTIVE: To evaluate systemic levels of bupivacaine after bilateral ultrasound-guided deep parasternal intercostal plan (PIP) block in cardiac surgical patients undergoing median sternotomy.
METHODS: Prospective, observational study SETTING: Single institution; academic university hospital PARTICIPANTS: Twenty-eight adult patients undergoing cardiac surgery with median sternotomy received a PIP block with 2.5 mg/kg bupivacaine with or without dexamethasone and dexmedetomidine.
METHODS: Arterial blood samples were analyzed for total serum bupivacaine concentration at 5, 15, 30, 45, 60, 90, 120, and 150 minutes after placement of PIP. Local anesthetic volume, local anesthetic adjuncts, time to extubation, postoperative pain scores, and opioid consumption were recorded.
RESULTS: The mean peak bupivacaine concentration was 0.60 ± 0.62 µg/mL, and the mean time to maximum concentration (Tmax) was 16.92 ± 12.97 minutes. Two patients (7.1%) had a concentration >2.0 µg/mL within 15 minutes of block placement. The mean Tmax of bupivacaine was significantly greater in patients who did not receive additives compared to those patients who did (22.86 ± 14.77 minutes v 10.0 ± 5.22 minutes; p = .004). The times to extubation and postoperative pain were not improved with additives.
CONCLUSIONS: Bilateral PIP placed at the end of cardiac surgery resulted in low systemic bupivacaine levels. The inclusion of additives shortened Tmax without improving outcome.
METHODS: Prospective, observational study SETTING: Single institution; academic university hospital PARTICIPANTS: Twenty-eight adult patients undergoing cardiac surgery with median sternotomy received a PIP block with 2.5 mg/kg bupivacaine with or without dexamethasone and dexmedetomidine.
METHODS: Arterial blood samples were analyzed for total serum bupivacaine concentration at 5, 15, 30, 45, 60, 90, 120, and 150 minutes after placement of PIP. Local anesthetic volume, local anesthetic adjuncts, time to extubation, postoperative pain scores, and opioid consumption were recorded.
RESULTS: The mean peak bupivacaine concentration was 0.60 ± 0.62 µg/mL, and the mean time to maximum concentration (Tmax) was 16.92 ± 12.97 minutes. Two patients (7.1%) had a concentration >2.0 µg/mL within 15 minutes of block placement. The mean Tmax of bupivacaine was significantly greater in patients who did not receive additives compared to those patients who did (22.86 ± 14.77 minutes v 10.0 ± 5.22 minutes; p = .004). The times to extubation and postoperative pain were not improved with additives.
CONCLUSIONS: Bilateral PIP placed at the end of cardiac surgery resulted in low systemic bupivacaine levels. The inclusion of additives shortened Tmax without improving outcome.
摘要：
目的：评价胸骨正中切开术患者行双侧超声引导胸骨旁肋间计划（PIP）阻滞后布比卡因的全身水平。
方法：前瞻性，观察性研究地点:单一机构;学术大学医院参与者:28例接受心脏正中胸骨切开术的成年患者接受了2.5mg/kg布比卡因联合或不联合地塞米松和右美托咪定的PIP阻滞.
方法:在PIP放置后5、15、30、45、60、90、120和150分钟分析动脉血样的总血清布比卡因浓度。局部麻醉剂量,局部麻醉辅助药物,拔管时间，术后疼痛评分,记录了阿片类药物的消费量。
结果：布比卡因平均峰值浓度为0.60±0.62µg/mL，达到最大浓度的平均时间(Tmax)为16.92±12.97分钟。两名患者（7.1％）在放置块的15分钟内浓度>2.0µg/mL。与接受添加剂的患者相比，未接受添加剂的患者的布比卡因的平均Tmax明显更大（22.86±14.77分钟v10.0±5.22分钟；p=.004）。添加剂不能改善拔管时间和术后疼痛。
结论：在心脏手术结束时放置双侧PIP会导致全身布比卡因水平降低。添加剂的包含缩短了Tmax而没有改善结果。
方法：前瞻性，观察性研究地点:单一机构;学术大学医院参与者:28例接受心脏正中胸骨切开术的成年患者接受了2.5mg/kg布比卡因联合或不联合地塞米松和右美托咪定的PIP阻滞.
方法:在PIP放置后5、15、30、45、60、90、120和150分钟分析动脉血样的总血清布比卡因浓度。局部麻醉剂量,局部麻醉辅助药物,拔管时间，术后疼痛评分,记录了阿片类药物的消费量。
结果：布比卡因平均峰值浓度为0.60±0.62µg/mL，达到最大浓度的平均时间(Tmax)为16.92±12.97分钟。两名患者（7.1％）在放置块的15分钟内浓度>2.0µg/mL。与接受添加剂的患者相比，未接受添加剂的患者的布比卡因的平均Tmax明显更大（22.86±14.77分钟v10.0±5.22分钟；p=.004）。添加剂不能改善拔管时间和术后疼痛。
结论：在心脏手术结束时放置双侧PIP会导致全身布比卡因水平降低。添加剂的包含缩短了Tmax而没有改善结果。
