Fearon Deirdre M, Steele Dale W
Department of Pediatrics and Section of Emergency Medicine, Brown Medical School, Pediatric Emergency Medicine, Hasbro Children's Hospital, Providence, RI, USA.
Acad Emerg Med. 2002 Dec;9(12):1373-8. doi: 10.1111/j.1553-2712.2002.tb01605.x.
Patients with diabetic ketoacidosis (DKA) hyperventilate, lowering their alveolar (PACO(2)) and arterial carbon dioxide (PaCO(2)). This ventilatory response lessens the severity of their acidemia in a predictable way. Because end-tidal CO(2) (ETCO(2)) closely approximates PaCO(2), measured ETCO(2) levels should allow for predictions about the presence and severity of acidosis in diabetic patients.
Children being evaluated in a pediatric emergency department for suspected DKA (known or suspected diabetes presenting with hyperglycemia with or without ketonuria) were enrolled in a cross-sectional, prospective, observational study. Prior to the availability of venous HCO(3) results, ETCO(2) values were measured using a Nellcor NPB-70 Handheld Capnograph.
Forty-two patients were enrolled. Linear regression analysis revealed a significant relationship between HCO(3) and ETCO(2) (R(2) = 0.80, p < 0.0001). Mean ETCO(2) was 37 torr (95% CI = 35.5 to 37.9 torr) in the children without DKA and 22 torr (95% CI = 17.4 to 26.9 torr) in the children with DKA (p < 0.0001). An ETCO(2) cut-point of <29 torr correctly classified the most patients (95%), with a sensitivity of 0.83 (95% CI = 0.52 to 0.98) and a specificity of 1.0 (95% CI = 0.88 to 1.0). No patient with an ETCO(2) of > or =36 torr had DKA, for a sensitivity of 1.0 (95% CI = 0.74 to 1.0).
End-tidal CO(2) is linearly related to HCO(3) and is significantly lower in children with DKA. If confirmed by larger trials, cut-points of 29 torr and 36 torr, in conjunction with clinical assessment, may help discriminate between patients with and without DKA, respectively.
糖尿病酮症酸中毒（DKA）患者会出现通气过度，导致肺泡二氧化碳分压（PACO₂）和动脉血二氧化碳分压（PaCO₂）降低。这种通气反应会以一种可预测的方式减轻其酸血症的严重程度。由于呼气末二氧化碳分压（ETCO₂）与PaCO₂密切相关，因此测量ETCO₂水平应有助于预测糖尿病患者酸中毒的存在及严重程度。
1）评估疑似DKA儿童中测量的血清碳酸氢盐（HCO₃）与通过鼻式二氧化碳监测仪测量的ETCO₂之间的关系；2）评估二氧化碳监测仪预测DKA的能力。
在儿科急诊科接受疑似DKA评估的儿童（已知或疑似糖尿病，伴有或不伴有酮尿症的高血糖症）被纳入一项横断面、前瞻性观察性研究。在获得静脉血HCO₃结果之前，使用Nellcor NPB - 70手持式二氧化碳监测仪测量ETCO₂值。
共纳入42例患者。线性回归分析显示HCO₃与ETCO₂之间存在显著关系（R² = 0.80，p < 0.0001）。无DKA儿童的平均ETCO₂为37托（95%CI = 35.5至37.9托），DKA儿童的平均ETCO₂为22托（95%CI = 17.4至26.9托）（p < 0.0001）。ETCO₂切点<29托能正确分类大多数患者（95%），敏感性为0.83（95%CI = 0.52至0.98），特异性为1.0（95%CI = 0.88至1.0）。ETCO₂≥36托的患者均无DKA，敏感性为1.0（95%CI = 0.74至1.0）。
呼气末二氧化碳分压与HCO₃呈线性相关，在DKA儿童中显著降低。如果通过更大规模的试验得到证实，29托和36托的切点，结合临床评估，可能分别有助于区分有无DKA的患者。
