1.Effects of acute normovolemic hemodilution on intrapulmonary shunting and oxygenation during one-lung ventilation in dogs
Ning MA ; Shuren LI ; Qingyuan KUI
Chinese Journal of Anesthesiology 2001;21(5):291-294
Objective To evaluate the effects of different degrees of acute normovolemic hemodilution (ANH) on intrapulmonary shunting, oxygen delivery and consumption during one-lung ventilation(OLV) in dogs. Methods Twelve healthy mongrel dogs weighing 18-22 kg were anesthetized with Ⅳ pentobarbital sodium 20mg.kg-1, scopolamine 0.3 mg and pancuronium 0.2 mg. kg-1 and intubated with a left-sided Carlen' s tube. Correct positioning of the tube was verified by auscultation and by visual inspection after thoracotomy at the end of the experiment. The dogs were mechanically ventilated with 100% oxygen. PET CO2 was maintained between 4.67-6.00 kPa. ECG and rectal temperature were continuously monitored. An intravenous line was established for infusion of Lacted Ringer solution. SwanGanz catheter was inserted via femoral vein on one side for sampling of mixed venous blood and measurement of cardiac output (CO) by hemodilution technique and pulmonary artery pressure (PAP).Femoral artery on the other side was cannulated for measurement of mean arterial pressure(MAP) and arterial blood sampling. The body temperature was maintained between 35℃-39℃ during the experiment.Four degrees of ANH were achieved by blood withdrawal and replacement with an equal volume of gelofusin step by step: HD1 (Hct 35%), HD2 (Hct 25%), HD3 (15%) and HD4(7%-8%). The volume of blood to be removed was based upon the patients' estimated blood volume [EBV = body weight (kg) ×7% ], the beginning Hct(Hct0) and the target Hct (Hctt) V = EBV × (Hct0-Hctt)/Hctav. During each degree of hemodilution(HD) two lungs were ventilated(TLV) first followed by one-lung ventilation(OLV)Each ventilation condition was maintained for at least 15 min, then hemodynamics was measured and blood gas analysis including blood concentration of lactate of both arterial blood and mixed venous blood was performed, then Qs/Qt, oxygen delivery (DO2) and oxygen consumption(VO2) were calculated. Results With increasing hemodilution, MAP, pulmonary vaseular resistance(PVR), mean pulmonary arterialpressure(MPAP), PO2 and DO2 had a tendency to decrease, While oxygen extraction ratio(ERO2 ), blood lactate and Qs/Qt tended to increase. There were DO2-dependent VO2 and anaerobic metabolism during HD3 and HD4. PVR and MPAP increased significantly when one lung was being ventilated before HD and during HD1 and HD2 . During HD3 and HD4 there was little difference in PVR and MPAP between OLV and TLV. Qs/Qt increased by 74% (HD2), 164% (HD3) and 177% (HD4) during OLV. Conclusions The results show that both ANH and OLV can affect Qs/Qt and oxygenation. The degree of ANH should be limited to Hct 25 % during OLV.consumpation
2.The influence of calling emergency medical services (EMS) on severity of disease among patients admitted to emergency room: A propensity-matched study
Kui JIN ; Kaipeng WANG ; Qingyuan LIU ; Yueguo WANG ; Yulan WANG ; Chongjian HUANG ; Huanli WANG ; Shusheng ZHOU ; Yinglei LAI ; Mengping ZHANG ; Jun XU
Chinese Journal of Emergency Medicine 2021;30(12):1514-1522
Objective:To evaluate the association between the use of emergency medical services (EMS) and the severity of disease among patients admitted to the emergency room, to analyze the characteristics of the patients, and to build prediction model providing evidence-based use of EMS resources.Methods:The data of patients admitted to the Emergency Room of the First Affiliated Hospital of University of Science and Technology of China from January 2020 to July 2021 were extracted from the Chinese Emergency Triage Assessment and Treatment (CETAT) database. Patients were divided into the EMS use group (AB+ group) and self-seeing group (AB-group) according to whether they used EMS. The patients’ general condition, vital signs and laboratory tests results were recorded. The severity of patients’ condition was judged based on whether the patient was admitted to the department of critical medicine, specialized care unit, emergency operation and/or emergency percutaneous intervention. A 9-variable model that did not require laboratory inspection and 22-variable model that required laboratory inspection were established to correct the propensity score to analyze the correlation between the severity of disease and the EMS use. In the subgroup analysis, the correlation between the EMS use and severity of the patients was analyzed according to the reason of the patient’s visit.Results:During the study period, 16 489 patients were admitted to the emergency room, and 6975 patients were finally enrolled in this study. There were 2768 patients (39.7%) in the AB+ group and 4207 patients (60.3%) in the AB-group. In the AB+ group 522 patients (18.9%) were in high risk, and in the AB-group 563 patients (13.4%) were in high risk. Compared with the AB-group, patients in the AB+ group were older and had a higher proportion of coma, a faster autonomic heart rate, and a lower diastolic blood pressure and peripheral oxygen saturation (SpO 2). In the 9-variable model, sex, consciousness, temperature, heart rate and diastolic blood pressure were associated with the EMS use. In the 22-variable model, consciousness, SpO 2, neutrophils, and albumin were the relevant factors for patients using EMS. Before the correction of propensity score, the EMS use was an independent risk factor for critically ill patients ( OR=1.5, 95% CI 1.32-1.72, P<0.001). After adjusted using 9-variable propensity score, the EMS use ratio decreased significantly compared with that without correction ( OR=1.24,95% CI 1.08-1.42, P<0.001). Interestingly, after adjusted with propensity score match with 22-variable model, there was no association between the severity of disease and t the EMS use ( OR=1.10,95% CI 0.95-1.28, P=0.195). In subgroup analysis, patients’ chief complaint of central nervous system, cardiovascular system, and trauma were the top three reasons at admission. Before the propensity score correction, the EMS calling patients with chief complaint of central nervous system, digestive system, and trauma were related to the severity of the patients. After adjusted with 9-variable model the EMS use was associated with the severity of the disease only in trauma patients, and after adjusted with 22-variable model there was no statistical difference considering the severity of the disease in all subgroups. Conclusions:The EMS use is common. However, the association of the EMS use with the severity of disease is decreased with variable models using propensity score. These findings indicate that the EMS use should be based on multivariable models, which may be important in detecting critically ill patients, optimizing the EMS use, and avoiding unnecessary call in the future.