儿科日间手术中超重（或肥胖症）与胃液特性的关系：在禁食指南和误吸风险评估方面的意义

背景超重或肥胖的日间手术儿科患者手术前2小时禁水的安全性尚未得到证实。健康的儿童和肥胖的成人在手术前禁水2小时后残留胃液量（GFVs）并不多，因此认为误吸风险并不高。因此我们将测算日间手术患者中超重症或肥胖症的患病率，并假设不管是体重指数还是禁食时间均不会对GFV或胃液pH值产生显著的影响。所有受试儿童均于手术前禁清水2小时，并假设超重或肥胖患儿的GFV不会多于偏瘦或正常体重患儿，而呕吐或误吸的风险也很低。方法本研究中连续纳入了1000例2－12岁行日间手术的患儿，记录人口统计学资料、病史、身高和体重。另外纳入1000例需全麻插管的日间手术患儿（2。12岁）进行研究。气管插管后，经口插入一根14—18F的胃管，抽空胃内容物。用药情况、禁食时间、GFV、pH值和呕吐事件均被详细记录。采用疾病预防及控制中心的生长图表（2000）评定理想体重（IBW=第50个百分位数），并对患儿进行分层：偏瘦或正常体重（BMI在第25—75个百分位数）、超重（第95个百分位数〈BMI≥第85个百分位数）、肥胖（BMI≥第95个百分位数）。结果在所有的日间手术患儿中有14％属于超重，13．3％属于肥胖。肥胖儿按公斤体重算出的GFV较低（P〈0．001）。当我们用IBW进行校正后，所有BMI组中GFV（mw校正后）的容量都相等（均值为0．96ml／kg，SD为0．71；中位数为0．86ml／kg，IQR为0．96）。手术前使用对乙酰氨基酚和咪达唑仑均导致GFV（1BW校正后）增加（P=0．025和P=0．001）。而ASA11I级（P=0．024）、男性（P=0．012）、胃食管反流性疾病（P=0．049）和使用质子泵抑制剂（P=0．018）患儿的GFV（mw校正后）较低。GFV（IBw校正后）与禁食时间和年龄无关。胃液酸度较低与年龄较小（P=0．005）、BMI较高（P=0．036）和美国非洲裔（P=0．033）患儿等因素相关。有8例患儿在全麻诱导时发生了呕吐（其中50％有肥胖症，P=0．052，75％患有阻塞性睡眠呼吸暂停症，P=0．061）。呕吐与ASA分级较高有关，但却与禁食时间的长短无关。研究中没有出现误吸事件。结论27％的儿科日闻手术患儿属超重或肥胖儿童。无论进食时间长短或BMI如何，GFV（IBw校正后）均为1ml／kg，因此这些患儿均可以在手术前2小时饮清水。在此研究群体中，罕见的呕吐事件与禁食时间的缩短并无相关性。

BACKGROUND： The safety of 2-h preoperative clear liquid fasts has not been established for overweight/ obese pediatric day surgical patients. Healthy children and obese adults who fasted 2 h have small residual gastric fluid volumes （GFVs）, which are thought to reflect low pulmonary aspiration risk. We sought to measure the prevalence of over-weight/obesity in our day surgery population. We hypothesized that neither body mass index （BMI） percentile nor fasting duration would significantly affect GFV or gastric fluid pH. In children who were allowed clear liquids up until 2 h before surgery, we hypothesized that overweight/obese subjects would not have increased GFV over lean/normal subjects and that emesis/pulmonary aspiration events would be rare. METHODS： Demographics, medical history, height, and weight were recorded for 1000 consecutive day surgery patients aged 2 - 12 yr. In addition, I000 day surgery patients （age 2 - 12 yr） undergoing general endotracheal anesthesia were enrolled. After tracheal intubation, a 14 - 18 F orogastric tube was inserted and gastric contents evacuated. Medications, fasting interval, GFV, pH, and emetic episodes were documented. Age- and gender-spedfic Center for Disease Control and Prevention growth charts （2000） were used to determine ideal body weight （IBW = 50th percentile） and to classify patients as lean/normal （BMI 25th - 75th percentile）, overweight （BMI 〉i 85th to 〈 95th percentile）, or obese （BMI ≥ 95th percentile）. RESULTS： Of all day surgery patients, 14. 0% were overweight and 13.3% were obese. Obese children had lower GFV per total body weight （P 〈 0. 001 ）. When corrected for IBW, however, volumes GFV （IBW） were identical across all BMI categories （mean 0. 96 ml/kg, sd O. 71; median 0.86 ml/kg, IQR 0. 96）. Preoperative acetaminophen and midazolam contributed to increased GFV （IBW） （P = O. 025 and P = 0. 001 ）. Lower GFV （IBW） was associated with ASA physical status Ill （P = 0. 024）, male gender （P = 0. 012）, gastroesophageal reflux disease （P = 0. 049）, and proton pump inhibitor administration （P = 0. 018）. GFV （IBW） did not correlate with fasting duration or age. Decreased gastric fluid acidity was assodated with younger age （P = 0. 005）, increased BMI percentile （P = 0. 036）, and African American race （P =0. 033）. Emesis on induction occurred in eight patients （50% of whom were obese, P = 0.052, and 75% of whom had obstructive sleep apnea, P = 0.061 ）. Emesis was associated with increased ASA physical status （P =0. 006） but not with fasting duration. There were no pulmonary aspiration events. CONCLUSIONS： Twenty-seven percent of pediatric day surgery patients are overweight/obese. These children may be allowed dear liquids 2 1, before surgery as GFV （IBW） averages 1 ml/kg regardless of BMI and fasting interval. Rare emetic episodes were not assodated with shortened fasting intervals in this population.