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Near-infrared spectroscopy (NIRS) could be a useful continuous, non-invasive technique for monitoring the effect of partial pressure of carbon dioxide (PaCO2) fluctuations in the cerebral circulation during ventilation. The aim of this study was to examine the efficacy of NIRS to detect acute changes in cerebral blood flow following PaCO2 fluctuations after confirming the autoregulation physiology in piglets. Fourteen piglets (<72 h of life) were studied. Mean arterial blood pressure, oxygen saturation, pH, glycemia, hemoglobin, electrolytes, and temperature were monitored. Eight animals were used to evaluate brain autoregulation, assessing superior cava vein Doppler as a proxy of cerebral blood flow changing mean arterial blood pressure. Another 6 animals were used to assess hypercapnia generated by decreasing ventilatory settings and complementary CO2 through the ventilator circuit and hypocapnia due to increasing ventilatory settings. Cerebral blood flow was determined by jugular vein blood flow by Doppler and continuously monitored with NIRS. A decrease in PaCO2 was observed after hyperventilation (47.6±2.4 to 29.0±4.9 mmHg). An increase in PaCO2 was observed after hypoventilation (48.5±5.5 to 90.4±25.1 mmHg). A decrease in cerebral blood flow after hyperventilation (21.8±10.4 to 15.1±11.0 mL/min) and an increase after hypoventilation (23.4±8.4 to 38.3±10.5 mL/min) were detected by Doppler ultrasound. A significant correlation was found between cerebral oxygenation and Doppler-derived parameters of blood flow and PaCO2. Although cerebral NIRS monitoring is mainly used to detect changes in regional brain oxygenation, modifications in cerebral blood flow following experimental PaCO2 changes were detected in newborn piglets when no other important variables were modified.
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Objective@#To analysis the transcutaneous carbon dioxide pressure(TcpCO2)in very low birth weight infant (VLBW) and extremely low birth weight infant (ELBW) after the time of tube drawing, and further guidance the management of premature ventilator breathing.@*Methods@#Premature infants with gestational age less than 32 weeks, birth weight below 1 500 g, hospitalized from March 2016 to December 2018 in our hospital, who needed early mechanical ventilation due to respiratory distress within 24 hours after birth and intended to be withdrawn were enrolled.Fifty-five infants in the observation group were monitored by TcpCO2 and blood gas was collected at 1 h, 6 h, 12 h, 24 h, 48 h, and 72 h after weaning; 55 infants in the control group were collected arterial blood gas only.When TcpCO2 monitoring and PaCO2 indicated hypercapnia, clinical intervention was actively given.The value of blood gas PaCO2 in the two groups and the TcpCO2 value of the observation group were recorded at different time points (1 h, 6 h, 12 h, 24 h, 48 h, 72 h) after weaning, and the failure of weaning was recorded in both group.@*Results@#There was no significant difference in the general information (gender, gestational age, birth weight, and whether prenatal maternal glucocorticoids) between the two groups (P>0.05). There were no significant differences in mechanical ventilation time, noninvasive ventilation mode and time between the two groups(P>0.05). The failure rate of withdrawal within 24 h and 72 h was lower in the observation group than the control group[3.6% (2/55) vs.14.0% (8/55), 7.3% (4/55) vs. 21.0% (12/55)], the difference was statistically significant (P<0.05). There was a significant difference in blood gas PaCO2 between the two groups at 6 h, 12 h, and 24 h after weaning (P<0.05), but had no significant difference between the two groups at 1 h, 48 h, and 72 h (P>0.05). The values of TcpCO2 and PaCO2 had no significant difference in the observation group at the same time point (P>0.05), and there was a correlation between them(r=0.761, P<0.05).@*Conclusion@#VLBW and ELBW undergoing mechanical ventilation are given continuous TcpCO2 monitorings after weaning, which not only has the characteristics of continuous and non-invasive monitoring, but also help to identify hypercapnia early and give symptomatic treatment, and reduce the incidence of weaning failure.And it proves a good correlation between TcpCO2 and PaCO2.
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Objective@#To evaluate microcirculatory changes after bundle therapy and prognostic values of the ratio of transcutaneous oxygen pressure and transcutaneous carbon dioxide pressure (PtcO2/PtcCO2) in the treatment of septic shock.@*Methods@#A retrospective analysis was conducted. Patients with septic shock admitted to department of intensive care unit (ICU) of Northern Jiangsu People's Hospital from July 2017 to February 2019 were enrolled. The gender, age, infection site, acute physiology and chronic health evaluationⅡ (APACHEⅡ), the length of ICU stay and 28-day prognosis were collected; PtcCO2, PtcO2, PtcO2/PtcCO2 ratio, arterial lactate (Lac), central venous oxygen saturation (ScvO2), mean arterial pressure (MAP) were measured before treatment (at admission) and 6 hours after bundle treatment. According to the 28-day prognosis, the patients were divided into survival group and death group, and the differences of each index between the two groups were compared. The risk factors of prognosis were analyzed by binary Logistic regression analysis. The receiver operating characteristic (ROC) curve was drawn to evaluate the predictive value of the related indicators for the 28-day mortality of septic shock patients.@*Results@#A total of 78 patients with septic shock were enrolled, with 47 cases in survival group and 31 cases in death group. Compared with survival group, APACHEⅡ score and PtcCO2 were higher and PtcO2/PtcCO2 ratio was lower in death group [APACHEⅡ: 28.33±6.35 vs. 21.61±6.64, PtcCO2 (mmHg, 1 mmHg = 0.133 kPa): 51.80±19.05 vs. 38.17±6.79, PtcO2/PtcCO2 ratio: 1.20±0.72 vs. 1.80±0.81, all P < 0.05]. Compared with before treatment, the PtcO2/PtcCO2 ratio, Lac, MAP were substantially improved at 6 hours of bundle therapy [PtcO2/PtcCO2 ratio: 1.76±0.81 vs. 1.56±0.82, Lac (mmol/L): 3.74±2.40 vs. 4.42±2.60, MAP (mmHg): 83.34±7.58 vs. 71.00±5.36, all P < 0.05], and there was no changes in PtcCO2 and ScvO2. The PtcO2/PtcCO2 ratio at 6 hours of bundle therapy in the survival group was significantly higher than before treatment and was higher than that in death group (2.13±0.75 vs. 1.80±0.81, 1.19±0.53, both P < 0.05). There was no significant difference in PtcO2/PtcCO2 ratio of death group before and after treatment (1.19±0.53 vs. 1.20±0.72, P > 0.05). The binary Logistic regression showed that PtcO2/PtcCO2 ratio at 6 hours of bundle therapy and APACHEⅡ score were risk factors of prognosis [PtcO2/PtcCO2 ratio: odds ratio (OR) = 7.876, P = 0.026; APACHEⅡ score: OR = 0.846, P = 0.035]. ROC curve analysis showed that 6-hour of PtcO2/PtcCO2 ratio, APACHEⅡscore and 6-hour Lac level could predict 28-day mortality in septic shock patients, and the area under curve (AUC) was 0.864, 0.784, and 0.752 respectively. The cut-off value of 6-hour PtcO2/PtcCO2 ratio for predicting mortality in septic shock patients was 1.42, the sensitivity was 87.0%, and the specificity was 73.3%. In addition, the patients were divided into two groups according to whether the 6-hour PtcO2/PtcCO2 ratio was greater than 1.42. The results showed that: compared with the PtcO2/PtcCO2 < 1.42 group, the APACHEⅡ score in PtcO2/PtcCO2 ≥ 1.42 group was lower, the 6-hour Lac level was lower, 24-hour Lac reaching standard rate was higher and the 28-day mortality was lower.@*Conclusions@#Compared with the traditional metabolic parameters, the improvement of early microcirculatory perfusion in patients with septic shock can reflect the effect of bundle therapy. The PtcO2/PtcCO2 ratio at 6 hours of bundle therapy can be used as a new index to predict the prognosis of patients with septic shock which supports the monitoring and evaluation of microcirculation in the early stage of treatment in septic shock.
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Objective To evaluate microcirculatory changes after bundle therapy and prognostic values of the ratio of transcutaneous oxygen pressure and transcutaneous carbon dioxide pressure (PtcO2/PtcCO2) in the treatment of septic shock. Methods A retrospective analysis was conducted. Patients with septic shock admitted to department of intensive care unit (ICU) of Northern Jiangsu People's Hospital from July 2017 to February 2019 were enrolled. The gender, age, infection site, acute physiology and chronic health evaluation Ⅱ (APACHEⅡ), the length of ICU stay and 28-day prognosis were collected; PtcCO2, PtcO2, PtcO2/PtcCO2 ratio, arterial lactate (Lac), central venous oxygen saturation (ScvO2), mean arterial pressure (MAP) were measured before treatment (at admission) and 6 hours after bundle treatment. According to the 28-day prognosis, the patients were divided into survival group and death group, and the differences of each index between the two groups were compared. The risk factors of prognosis were analyzed by binaryLogistic regression analysis. The receiver operating characteristic (ROC) curve was drawn to evaluate the predictive value of the related indicators for the 28-day mortality of septic shock patients. Results A total of 78 patients with septic shock were enrolled, with 47 cases in survival group and 31 cases in death group. Compared with survival group, APACHEⅡ score and PtcCO2 were higher and PtcO2/PtcCO2 ratio was lower in death group [APACHEⅡ:28.33±6.35 vs. 21.61±6.64, PtcCO2 (mmHg, 1 mmHg = 0.133 kPa): 51.80±19.05 vs. 38.17±6.79, PtcO2/PtcCO2 ratio: 1.20±0.72 vs. 1.80±0.81, all P < 0.05]. Compared with before treatment, the PtcO2/PtcCO2 ratio, Lac, MAP were substantially improved at 6 hours of bundle therapy [PtcO2/PtcCO2 ratio: 1.76±0.81 vs. 1.56±0.82, Lac (mmol/L):3.74±2.40 vs. 4.42±2.60, MAP (mmHg): 83.34±7.58 vs. 71.00±5.36, all P < 0.05], and there was no changes in PtcCO2 and ScvO2. The PtcO2/PtcCO2 ratio at 6 hours of bundle therapy in the survival group was significantly higher than before treatment and was higher than that in death group (2.13±0.75 vs. 1.80±0.81, 1.19±0.53, both P < 0.05). There was no significant difference in PtcO2/PtcCO2 ratio of death group before and after treatment (1.19±0.53 vs. 1.20±0.72, P > 0.05). The binary Logistic regression showed that PtcO2/PtcCO2 ratio at 6 hours of bundle therapy and APACHEⅡ score were risk factors of prognosis [PtcO2/PtcCO2 ratio: odds ratio (OR) = 7.876, P = 0.026; APACHEⅡscore: OR = 0.846, P = 0.035]. ROC curve analysis showed that 6-hour of PtcO2/PtcCO2 ratio, APACHEⅡscore and 6-hour Lac level could predict 28-day mortality in septic shock patients, and the area under curve (AUC) was 0.864, 0.784, and 0.752 respectively. The cut-off value of 6-hour PtcO2/PtcCO2 ratio for predicting mortality in septic shock patients was 1.42, the sensitivity was 87.0％, and the specificity was 73.3％. In addition, the patients were divided into two groups according to whether the 6-hour PtcO2/PtcCO2 ratio was greater than 1.42. The results showed that: compared with the PtcO2/PtcCO2 < 1.42 group, the APACHEⅡ score in PtcO2/PtcCO2 ≥ 1.42 group was lower, the 6-hour Lac level was lower, 24-hour Lac reaching standard rate was higher and the 28-day mortality was lower. Conclusions Compared with the traditional metabolic parameters, the improvement of early microcirculatory perfusion in patients with septic shock can reflect the effect of bundle therapy. The PtcO2/PtcCO2 ratio at 6 hours of bundle therapy can be used as a new index to predict the prognosis of patients with septic shock which supports the monitoring and evaluation of microcirculation in the early stage of treatment in septic shock.
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Objective To analysis the transcutaneous carbon dioxide pressure(TcpCO2 )in very low birth weight infant (VLBW) and extremely low birth weight infant (ELBW) after the time of tube drawing, and further guidance the management of premature ventilator breathing. Methods Premature infants with gestational age less than 32 weeks, birth weight below 1 500 g, hospitalized from March 2016 to December 2018 in our hospital,who needed early mechanical ventilation due to respiratory distress within 24 hours after birth and intended to be withdrawn were enrolled. Fifty-five infants in the observation group were monitored by TcpCO2 and blood gas was collected at 1 h, 6 h, 12 h, 24 h, 48 h, and 72 h after weaning;55 infants in the control group were collected arterial blood gas only. When TcpCO2 monitoring and PaCO2 indicated hy-percapnia, clinical intervention was actively given. The value of blood gas PaCO2 in the two groups and the TcpCO2 value of the observation group were recorded at different time points (1 h, 6 h, 12 h, 24 h, 48 h, 72 h) after weaning,and the failure of weaning was recorded in both group. Results There was no significant difference in the general information ( gender, gestational age, birth weight, and whether prenatal maternal glucocorticoids) between the two groups ( P>0. 05). There were no significant differences in mechanical ventilation time, noninvasive ventilation mode and time between the two groups(P>0. 05). The failure rate of withdrawal within 24 h and 72 h was lower in the observation group than the control group[3. 6% (2/55) vs. 14. 0% (8/55), 7. 3% (4/55) vs. 21. 0% (12/55)], the difference was statistically significant ( P< 0. 05). There was a significant difference in blood gas PaCO2 between the two groups at 6 h, 12 h, and 24 h after weaning (P<0. 05), but had no significant difference between the two groups at 1 h, 48 h, and 72 h (P>0. 05). The values of TcpCO2 and PaCO2 had no significant difference in the observation group at the same time point (P>0. 05),and there was a correlation between them(r＝0. 761, P<0. 05). Conclusion VLBW and ELBW undergoing mechanical ventilation are given continuous TcpCO2 monitorings after wea-ning, which not only has the characteristics of continuous and non-invasive monitoring, but also help to iden-tify hypercapnia early and give symptomatic treatment,and reduce the incidence of weaning failure. And it proves a good correlation between TcpCO2 and PaCO2 .
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Objective To analyze the relevant factors of early warning in emergency patients with high risk of acute sores, explore the application value of transcutaneous oxygen pressure(TcPO2) and transcutaneous carbon dioxide pressure(TcPCO2)monitoring in the early warning of emergency patients with pressure ulcers. Methods This was a study of 186 consecutive emergency patients who were under care in the emergency department. The transcutaneous oxygen/carbon dioxide pressure monitor was used in monitoring the oxygen saturation of the skin of sacrococcygeal region and the chest. Meanwhile,the Braden scale was used in assessing risk factors for pressure ulcers and the receiver operating characteristic curve (ROC curve) was applied to evaluate the early prediction of pressure sore with TcPO 2/TcPCO2 monitor. Results Implementing the logistic regression model with six indicators, this research concluded that TcPO2 CV and PO2 were independent risk factors for the development of Braden scale in patients with high risk. The area under the ROC curve showed that TcPO2 CV had a excellent predictive value for the high-risk group and determined its cut-off value to be 20％. Which means patient with both a value of TcPO2CV over 20％ and a high risk of Braden scale had a larger possibility of pressure ulcers. Conclusions TcPO2 CV was an independent risk factor for patients under emergency care to develop pressure ulcers. A value of TcPO2CV over 20％indicated a high risk of pressure ulcers.
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Objective:To investigate the relative expression of matrix metalloproteinases-2, 3 (MMP-2, 3) and tissue inhibitors of metalloproteinases-1, 2 (Tissue Inhibitor of Metalloproteinase-1, 2, TIMP-1, 2) in ovarian cancer cell line A2780 under different pressures controlled by carbon dioxide (CO2) changes at different time points and their meaning.Methods:Cell model was established by culture and grouping of A2780 ovarian cancer cell line in vitro.By simulation of laparoscopic CO2pneumoperitoneum environment under different pressure in vitro the pressure of carbon dioxide is controlled at 0 mmHg, 7 mmHg and 15 mmHg respectirely, the cells were collected at 0, 12, 24 and 48 hours after the CO2pressure was controlled for 3 hours.Total RNA was extracted and RT-qPCR was performed to detect the relative expression of MMP-2, 3, TIMP-1 and 2 mRNA in each group.Results:After CO2pressure control, the relative expression of MMP-2 mRNA in each sample under the same pressure decreased with the duration of culture.After CO2pressure control, the relative expression of MMP-2 in ovarian cancer cells decreased with the increase of CO2pressure at the same time point.After CO2pressure control, the relative expression of MMP-3 mRNA in each sample underthe same pressure decreased with the culture time.After CO2pressure control, the relative expression of MMP-3 in ovarian cancer cells decreased with the increase of CO2pressure at the same time point.There was no significant difference in the relative expression of TIMP-1 and TIMP-2 mRNA between the control group and the experimental group at different time points orunder different CO2pressures (P＞0.05).Conclusions:The simulated CO2pneumoperitoneum environment could inhibit the invasive ability of ovarian cancer cell line A2780.The relative expression of MMP-2 and MMP-3 decreased astime and pressure increasing.The simulated CO2pneumoperitoneum environment had no significant effect on the expression of A2780 TIMP-1 and 2 mRNA in ovarian cancer cell line A2780.
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Objective To investigate the clinical significance and correlation of end-tidalcarbon dioxide partial pressure (PetCO2) and arterial blood carbon dioxide pressure (PaCO2) of children with different types of congenital heart disease in perioperative period of cardiopulmonary bypass.Methods 60 children undergoing selective cardiopulmonary bypass surgery for congenital heart disease were chosen (aged 1-14 years old, ASA class II or III).According to echocardiographic results, the children were divided into two groups. Group A:Left-to-right shunt in children, involving 15 cases of atrial septal defect and 15 cases of ventricular septal defect;Group B: Right-to-left shunt in children, involving 30 cases of Fallot tetrad. All 60 children underwent intravenous general anesthesia and rapid induction of orotracheal intubation. All patients underwent ventilator-assisted ventilation in the surgical intensive care unit for 8 hours after surgery. The brachial artery blood was collected for arterial blood gas analysis to measure PaCO2 at the beginning of surgery (T1), 15 min after anesthesia (T2), before CPB (T3), 15 min after CPB (T4), end of surgery (T5), time to transfer to SICU (T6), 2 h after monitored in ICU (T7), 4 h after monitored in SICU (T8), 6 h after monitored in SICU (T9), 8 h after monitored in SICU (T10).The PaCO2 and PetCO2 were recorded at each time point. According to the result of PetCO2 and PaCO2, we studied the correlation of the two indexes at each time point.Results In group A, there was a positive correlation between PetCO2 and PaCO2 at each time point (the correlation was 0.55 to 0.87, P＜0.001). The correlation between PETCO2 and PaCO2 decreased gradually during T2-6, and the correlation gradually increased during T7-10. There was no significant correlation between PetCO2 and PaCO2 (the correlation was0.21 to 0.38, P＞ 0.05) before operation in group B until 15 minutes after CPB. From the end of surgery to 8 hours after SICU monitoring, PetCO2 was positively correlated with PaCO2 (the correlation was0.54 to 0.83, P ＜ 0.05).The correlation between the two indexes increased gradually during T5-10. Conclusions During the perioperative period of cardiopulmonary bypass, PetCO2 can be used as an evaluation indicator for clinical monitoring in the children with Left-to-right shunt of congenital heart disease.There was no significant correlation between PetCO2 and PaCO2 in the children with congenital heart disease of right-to-left shunting before the end of surgery. PetCO2 could not replace PaCO2.With the improvement of postoperative conditions, It is significant to dynamically observe changes in PetCO2 to guide the analysis of PaCO2.
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ResumenIntroducción:La dinámica cardíaca ha sido caracterizada a partir de la teoría de los sistemas dinámicos y la geometría fractal, permitiendo generar metodologías de aplicación clínica.Objetivo:desde los sistemas dinámicos, se desarrollará una metodología de evaluación de los pH y presiones de dióxido de carbono arteriales y venosos para pacientes de la Unidad de Cuidados Intensivos.Materiales y Métodos:se escogieron 10 pacientes con diversas patologías de la Unidad de Cuidados Intensivos Postqui rúrgicos del Hospital Militar Central, registrando pH y presiones de dióxido de carbono arteriales y venosas durante su tiempo de estancia; posteriormente se construyeron atractores, determinando su tipo de trayectoria y estableciendo los valores máximos y mínimos de estas variables en el mapa de retardo.Resultados:se encontró un comportamiento caótico de las variables evaluadas, hallando valores mínimos y máximos de 7,01 y 7,59 para pH arterial, 6,97 y 7,53 para pH venoso, 14,40 y 73,70 para presión arterial de dióxido de carbono, y 19,20 y 97,90 para presión venosa de dióxido de carbono.Conclusiones:La evaluación de los valores máximos y mínimos del atractor en el mapa de retardo constituye un nuevo método, objetivo y reproducible, para la evaluación matemática de cada una de las variables estudiadas, de utilidad para el seguimiento de pacientes en UCI.
SummaryIntroduction:Cardiac dynamics has been characterized from the theory of dynamical systems and fractal geometry, allowing to generate methodologies with clinical application. Objective: from dynamic systems, a methodology for evaluating the arterial and venous pH and dioxide of carbon pressures for patient in Intensive Care Unit will be developed.Materials and Methods:10 patients with various pathologies were selected from Post-surgical Intensive Care Unit of the Central Military Hospital, recording arterial and venous pH and dioxide of carbon pressures of during its stay; attractors were built subsequently, determining the type of path and setting the maximum and minimum values of these variables on the delay map.Results:chaotic behavior of the variables evaluated was found, finding maximum and minimum values of 7,01 and 7,59 for arterial pH values, 6,97 and 7,53 for venous pH, 14,40 and 73,70 for arterial dioxide of carbon pressure, and 19,20 and 97,90 for venous dioxide of carbon pressure.Conclusions:The evaluation of the maximum and minimum values of the attractor on the delay map is a new method, objective and reproducible for the mathematical evaluation of each of the variables studied, useful for monitoring patients in Intensive Care Unit.
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Humans , Venous Pressure , Blood Gas Analysis , Carbon Dioxide , Hypocapnia , Critical Care , Arterial Pressure , Hypercapnia , Intensive Care UnitsABSTRACT
Non-invasive transcutaneous monitoring(TCM) of oxygen and carbon dioxide,with continuous,non-invasive characteristics,is in common use and significant in the neonatal intensive care unit (NICU),which can directly reflect critically ill newborns'changes of respiratory and circulatory function.This review describes how to use TCM appropriately,compares the advantages and disadvantages of TCM with other monitoring devices,introduces its application in neonatal transport and NICU.
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Objective To evaluate the relevance of PET CO 2 ,TcPCO 2 and PaCO 2 in pediatric patients with congenital heart disease.Methods Eighty pediatric patients with congenital heart disease were scheduled for elective cardiac operation with cardiopulmonary bypass,aged 1 month to 5 years, 42 male and 38 female,were divided into 4 groups:group N1,cyanotic type congenital heart disease with severe pulmonary hypertension;group N2,cyanotic type congenital heart disease without pul-monary hypertension;group N3,non-cyanotic congenital heart disease with severe pulmonary hyper-tension;group N4,non-cyanotic congenital heart disease with mild pulmonary hypertension or normal of pulmonary artery pressure,20 cases in each group.The same anesthesia methods were selected in each group.PET CO 2 ,TcPCO 2 and PaCO 2 before operation were recorded,and the relevance among them was analyzed.Results In groups N1,N2 and N3,the differences of PET CO 2 and PaCO 2 were significant,,while the difference was relatively small in group N4;the difference of TcPCO 2 and PaCO 2 were relatively small between the four groups.In Groups N1,N2 and N3,the values of TcP-CO 2-PaCO 2 value were significantly less than that of PET CO 2-PaCO 2 ;in group N4,TcPCO 2-PaCO 2 value was obviously higher than that of PET CO 2-PaCO 2 values (P 0.05,0.02
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Objective To test whether the changes of partial end-tidal carbon dioxide pressure (PETCO2) during passive leg raising (PLR) predict fluid responsiveness in mechanically ventilated patients with septic shock.Methods Forty-two mechanically ventilated patients with septic shock admitted from January 2012 to November 2012 were prospectively recruited.Hemodynamic parameters monitored by a pulse indicator continuous cardiac output(PiCCO) device and PETCO2 monitored by an expiratory-CO2 device were studied at baseline,after PLR,and after volume expansion.Fluid responsiveness was defined as an increase in cardiac index (CI) of 15％ or greater after volume expansion.The correlation between PLR-induced CI change (△CIPLR) and PETCO2 (△PETCO2-PLR) was analyzed.The value of △PETCO2-PLR to predict fluid responsiveness was evaluated by receiver operating characteristic (ROC) curves.Results A total of 42 patients were enrolled in this study,of whom,24 had a CI increase of ≥ 15％ after volume expansion (responders).After PLR,CI and PETCO2 were both significantly increased in the response group compared with baseline [(21.4 ± 12.9) ％ of CI and (9.6 ± 4.7) ％ of PETCO2,P ＜ 0.05],while no significant changes were observed (P ＞ 0.05) in the non-response group.Both △CIPLR and △PETCO2-PLR were significantly higher in responder group than in the non-responder group (both P ＜ 0.05).△CI and △PETCO2 after PLR were strongly correlated (r =0.64,P ＜ 0.05).In responders after PLR,the area under ROC curve of △PETCO2-PLR was 0.900 ± 0.056 (95％ CI 0.775-1.000,P ＜ 0.05).An increase of ≥ 5％ in △PETCO2-PLR predicted fluid responsiveness with a sensitivity of 88.0％ and specificity of 88.2％.Conclusions The change of PETCO2 induced by passive leg raising is a non-invasive and easy way to predict fluid responsiveness in mechanically ventilated patients with septic shock.
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Objective To study the influence of environment oxygen supplement and passive smoking on the blood gas indexes in rabbits.Methods Eighty adult Newzealand white rabbits were randomly divided into 4 groups,20 in each.The oxygen supplement and passive smoking group was exposed to cigarette smoke produced by 25 burning cigarettes,four hours per time,consecutively for twenty-four hours,simultaneously exposed to oxygen produced by two oxygen generators(600-1 000 ml/min per generator).The oxygen supplement group was exposed to oxygen produced by two oxygen generators(600-1 000 ml/min per generator) consecutively for twenty-four hours.The passive smoking group was exposed to cigarette smoke produced by 25 burning cigarettes,four huors per time,consecutively for twenty-four hours.The control group was exposed to general feeding environment.The analysis of variance of factorial design(2?2) was conducted,five blood gas indexes were measured.Results Under the condition of surroundings oxygen increasing,the partial pressure of blood oxygen was improved significantly(P0.05).No evident interaction was found between surroundings oxygen increasing and passive smoking.Conclusion Oxygen metabolism can be improved by environment oxygen supplement in rabbits,and the effect of passive smoking on the investigated five blood gas indexes is not considered significant.