急性非等容量血液稀释用于围术期老年患者的可行性

Acute non-isovolemlc hemodilution during operation In the elderly patients

目的评估老年患者使用非等容量血液稀释(ANIH)的有效性及安全性,并与急性高容量血液稀释比较。方法38例老年患者,年龄65～80岁,ASA Ⅰ～Ⅱ级,随机分为两组:ANIH组(Ⅰ组),AHH组(Ⅱ组)。均采用硬膜外复合全麻。全麻诱导同时快速补充6％羟乙基淀粉1 000～1 200ml和乳酸林格氏液500 ml(25％～30％循环血量),Ⅰ组患者在诱导前采血400～600 ml(循环血量的10％～15％),并于手术结束前或预计Hct<24％予以回输。监测HR、BP、CVP、ST-T的变化,并抽血检测围术期Hct、胶体渗透压、动脉血乳酸的水平。结果 两组患者围术期生命体征平稳,诱导后两组各有16.7％(I组3/18)和15.O％(Ⅱ组3/20)的患者出现一过性的低血压,但两组患者CVP在血液稀释后均显著升高,Ⅱ组的升幅显著高于Ⅰ组(P<0.01)。Ⅱ组中有1例出现房颤。血常规检测提示,ANIH组的患者达到了中度血液稀释的目的(稀释后Hct:29.9％±3.9％),而AHH组仅可达到轻度血液稀释(稀释后Hct:32.9％±2.9％);手术结束时ANIH组的Hct显著高于AHH组分别为:31.5％±5.1％和27.7％±3.6％(P<0.01),而两组的出血量、各时段的胶体渗透压和动脉血乳酸水平无显著变化,均在正常值范围内。结论 ANIH稀释效率高,容量负荷干扰小,红细胞保护程度高,较AHH有更多的安全性和有效性,适合于老年患?

Objective Elderly patients with reduced cardiac function are not considered good candidates for acute isovolemic hemodilution ( AIH) and acute hypervolemic hemodilution ( AHH) significantly increases preload in these patients. We tried to develop an in-between technique, acute non-isovolemic hemodilution (ANIH). The purpose of this study was to evaluate the effectiveness and safety of ANIH in the elderly patients in comparison with AHH.Methods Thirty-eight ASA Ⅰ -Ⅱ patients of both sexes, aged between 65-80 yr, undergoing elective surgery were enrolled in this study. Their preoperative Hct was > 35 % and the intraoperative blood loss was expected to be 800-1 600 ml. The operations were performed under combined general-epidural anesthesia. General anesthesia was induced with fentanyl 2-4 μg·kg-1 , thiopentone 5 mg·kg-1 and succinylcholine 1.5mg· kg-1 and maintained with isoflurane inhalation and intermittent iv boluses of vecuronium. Epidural anesthesia was performed at T5-6 (thoracic surgery), T10-11 (upper abdominal surgery) or L3-4 (lower abdominal surgery) . A mixture of 0.1% lidocaine +0.2% dicaine was used for epidural block during operation. The patients were randomly divided into 2 groups: (1) ANIH group ( n = 18) and (2) AHH group ( n = 20) . Blood volume (BV) was calculated according to following formula: BV (ml) (male) = Height (cm)× 28.5 + Body weight (kg) × 31.6 - 2 820,BV(ml) (female) = Height(cm)× 16.25 + Body weight (kg) × 38.46 - 1 369. 1 000-1 200 ml of 6% HES (200/0.5) and 500 ml of lactated Ringer's solution (about 25%-30% of BV) were infused at a rate of 50ml·min-1 when induction of anesthesia was started in both groups. In group I (ANIH) 400-600 ml of blood (about 10%-15% of BV) was removed through radial artery before induction of anesthesia. The removed blood was reinfused at the end of surgery. Vital signs (BP,HR,CVP and ST-T changes) , Hct, oncotic pressure and arterial blood lactate concentration were monitored during operation. Results The vital signs were fairly stable during perioperative period in both groups. Transient hypotension developed in 16.7% (3/8 in group Ⅰ ) and 15.0% (3/20 in group Ⅱ ) of patients during induction of anesthesia. CVP was significantly elevated in both groups but the increase in CVP was significantly higher in group Ⅱthan that in group Ⅰ . In group Ⅰ (AN1H) moderate hemodilution was achieved (Hct = 29.9% 2.9%) while in group Ⅱ (AHH) only mild hemodilution was achieved (Hct = 32.9% ±2.9%) .Hct was significantly higher in group Ⅰ(31.5% ±5.1%) than that in group Ⅱ (27.7% ±3.6%) at the end of surgery. Blood loss was comparable between the two groups, and oncotic pressure and blood lactate level were within normal range in both groups. Conclusion ANIH is more effective and safer than AHH without obvious adverse effects, and can avoid exceedingly high CVP commonly seen in AHH. ANIH is a hemodilution technique of choice in the elderly patients.