Mixed venous to arterial CO 2 gap as a marker to identify fluid responsiveness in septic shock patients / 中华急诊医学杂志

Objective:To investigate the value of the venous-to-arterial CO 2 gap (Δ CO 2 gap) before and after the fluid challenge (FC) in determining the fluid responsivenessin septic shock patients. Methods:A total of 104 septic shock patients admitted to the Medical Intensive Care Unit (MICU) of Peking Union Medical College Hospital were included in the retrospective study. All patients were monitored by Swan Ganz floating catheter during the FC. Hemodynamics and blood gas indices were collected before FC (T0) and immediately (T1), 10 min (T2), 30 min (T3) and 60 min (T4) after FC. Responders were defined as patients with a > 10% increase in cardiac output (CO) after FC. Spearman correlation analysis was used to evaluate the correlation between CO 2 gap and CO. The value of ΔCO2 gap were calculated by the area under the receiver operating characteristic (AUROC) curve in the whole population. Results:Among 104 patients, the effective rates of FC at T1, T2, T3 and T4 were 59% (61/104), 72% (75/104), 73% (76/104), and 77% (80/104), respectively. CO of patients in the reactive group was lower than that in the non-reactive group at T2 [6.0 (4.7, 7.5) vs. 7.2 (6.4, 8.5) L/min, P=0.019], and there was no significant difference in CO 2 gap between the two groups before FC. Spearman correlation analysis showed that CO 2 gap was negatively correlated with CO, and the correlations between CO 2 content gap and CO was -0.34, and -0.33 of CO 2 pressure gap and CO, respectively (both P <0.05). ROC curve analysis showed that the ΔCO 2 gap at T1 could weakly judge the reactivity at T2, T3 and T4, but could not judge the reactivity at T1. The AUROC at T2 was 0.669 of ΔCO 2 content gap and 0.684 of ΔCO 2 pressure gap (both P <0.05). Conclusions:The evaluate time judging the effect of FC should be appropriately extended. The change value of CO 2 gap before and immediately after volume expansion in septic shock patients can judge the fluid responsiveness within 10 min after FC.

Evaluation of fluid responsiveness in patients with septic shock by critical ultrasound with small dose fluid challenge / 中华危重病急救医学

Objective:To explore the value of critical ultrasound in evaluating the fluid responsiveness of small dose volume challenge in patients with septic shock.Methods:Thirty-six patients with septic shock admitted to the Third People's Hospital of Datong from January 2021 to December 2021 were enrolled, and the patients were randomly divided into control group and observation group, with 18 patients in each group. The control group was treated with traditional fluid challenge (500 mL of crystalloid injected within 30 minutes); the observation group received a small dose fluid challenge (100 mL of crystalloid injected within 1 minute). The hemodynamic indexes [central venous pressure (CVP), invasive mean arterial pressure (MAP), velocity-time integra (VTI)] and bilateral lung ultrasound scores were measured by critical ultrasound in both groups. The outcome related indicators of patients in the two groups were observed. The correlation between the above indexes and the fluid challenge was evaluated.Results:Compared with the control group, the heart rate (HR) and CVP of patients in the observation group after the challenge were significantly lower than those in the control group [HR (times/min): 99.74±3.22 vs. 107.65±3.14, CVP (mmHg, 1 mmHg ≈ 0.133 kPa): 7.55±0.22 vs. 10.26±0.52, both P < 0.05], invasive MAP and VTI were significantly higher than those in the control group [invasive MAP (mmHg): 77.36±2.14 vs. 69.81±2.56, VTI (cm/s): 68.85±1.26 vs. 44.71±1.28, both P < 0.05]. The ultrasonic score of the observation group was significantly better than those of the control group (all P < 0.05). In terms of outcome, the length of intensive care unit (ICU) stay, mechanical ventilation time and the time for urine volume more than 0.5 mL·kg -1·h -1 of the observation group were significantly shorter than those in the control group [the length of ICU stay (hours): 138.26±1.25 vs. 205.73±1.26, mechanical ventilation time (hours): 36.80±0.25 vs. 47.65±0.36, time to reach urine volume more than 0.5 mL·kg -1·h -1 (hours): 27.38±1.25 vs. 38.61±1.30, all P < 0.05], The dosage of norepinephrine was significantly decreased in the observation group compared with the control group (mg: 45.26±1.85 vs. 53.73±1.92, P < 0.05), and the amount of resuscitation crystalloid was significantly reduced compared with the control group (mL: 1 532.62±12.38 vs. 1 755.52 ± 12.30, P < 0.05). Correlation analysis showed that the volume of crystalloid was highly consistent with M-BLUE pulmonary ultrasound (zone 2, 4 and 5), mechanical ventilation time, norepinephrine dose, time to reach the standard of urine volume and ΔVTI (all P < 0.05). Conclusions:Small dose fluid challenge evaluated by critical ultrasound in septic shock patients has a high value for fluid responsiveness, which can better reduce the risk of obvious tissue edema caused by fluid overload, organ damage and even life-threatening, make fluid challenge more reasonable and appropriate, thereby improving the success of treatment.

Evaluation of volume responsiveness by pulse pressure variability and inferior vena cava dispensability index at different tidal volumes by mechanical ventilation

This study investigated the effects of tidal volume (TV) on the diagnostic value of pulse pressure variation (PPV) and the inferior vena cava dispensability index (IVC-DI) for volume responsiveness during mechanical ventilation. In patients undergoing elective surgery with mechanical ventilation, different TVs of 6, 9, and 12 mL/kg were given for two min. The left ventricular outflow tract velocity-time integral (VTI) was measured by transthoracic echocardiography. The IVC-DI was measured at sub-xyphoid transabdominal long axis. The PPV was measured via the radial artery and served as baseline. Index measurements were repeated after fluid challenge. VTI increased by more than 15% after fluid challenge, which was considered as volume responsive. Seventy-nine patients were enrolled, 38 of whom were considered positive volume responsive. Baseline data between the response group and the non-response group were similar. Receiver operating characteristic curve confirmed PPV accuracy in diagnosing an increase in volume responsiveness with increased TV. When TV was 12 mL/kg, the PPV area under the curve (AUC) was 0.93 and the threshold value was 15.5%. IVC-DI had the highest diagnostic accuracy at a TV of 9 mL/kg and an AUC of 0.79, with a threshold value of 15.3%. When TV increased to 12 mL/kg, the IVC-DI value decreased. When the TV was 9 and 12 mL/kg, PPV showed improved performance in diagnosing volume responsiveness than did IVC-DI. PPV diagnostic accuracy in mechanically ventilated patients was higher than IVC-DI. PPV accuracy in predicting volume responsiveness was increased by increasing TV.

Choice of assessment time after fluid challenge in patients with septic shock / 中华危重病急救医学

Objective To explore the short-term hemodynamic change of fluid challenge (FC) with crystalloid or colloid and define fluid responsiveness at the optimal time in patients with septic shock. Methods A prospective observational study was conducted. Septic shock patients monitored with pulmonary catheters admitted to medical intensive care unit (ICU) of the Peking Union Medical College Hospital from July 2016 to December 2018 were enrolled. All included patients received FC and were divided into two groups according to the type of fluid used, i.e. crystalloid group (normal saline for 500 mL) and colloid group (4% succinyl gelatin for 500 mL). The choice of fluid type was decided by the attending physician. Hemodynamic variables were measured at baseline, and 0 (immediately), 10, 30, 45, 60, 90, 120 minutes after FC, included cardiac index (CI), heart rate (HR), mean artery pressure (MAP), central venous pressure (CVP) and pulmonary arterial wedge pressure (PAWP). Fluid responsiveness was defined as CI increased by more than 10% after FC. The data were analyzed by repeated measurements of variance between the two groups as well as responders and nonresponders. Results Forty patients were included, 20 cases each in colloid group and crystalloid group; of whom 26 were fluid responders with 12 of colloid group and 14 of crystalloid group. Of the 14 nonresponders, 8 were of colloid group and 6 of crystalloid group. ① Compared with before FC, CI (mL·s-1·m-2) was significantly increased in crystalloid and colloid groups after FC (71.7±16.7 vs. 65.0±16.7, 68.3±25.0 vs. 63.3±23.3, both P < 0.05). In the colloid group, volume expansion increased the CI to maximum (76.7±18.3) at 30 minutes after FC, at 120 minutes after FC, a significantly higher CI (70.0±16.7) was also observed (P < 0.05), an increased in CI≥10% was observed at 60 minutes after FC. In the crystalloid group, CI was increased to maximum at 10 minutes (73.3±28.3) and decreased to baseline at 60 minutes, an increased in CI≥10% was also observed at 10 minutes after FC. In addition, there was no significant difference in CI changes between colloidal group and crystalloid group at different time points after FC. ② CI did not change over time in nonresponders groups, whereas in responders CI increased parallelly to that in both crystalloid and colloid groups over time. However, an increased in CI≥10% was observed through the 120 minutes after FC in responders of colloid group compared with that of at 30 minutes after FC in crystalloid group. There was significant difference in CI changes between colloidal group and crystalloid group at 30, 45, 60, 90 minutes after FC (mL·s-1·m-2: 18.3±3.3 vs. 8.3±1.7, 18.3±3.3 vs. 5.0±1.7, 13.3±1.7 vs. 3.3±1.7, 11.7±3.3 vs. 3.3±1.7, all P <0.05). ③ The maximal values of CVP and PAWP were observed at the end of FC. In colloid group, both the two variables were notably higher than that before FC over 120 minutes compared with that of only at 10 minutes in crystalloid group. The MAP in colloid increased to maximum immediately at the end of FC and decreased to baseline at 45 minutes, however, the MAP in crystalloid group and HR of both groups showed no differences over 120 minutes. Conclusions Hemodynamic changes were significantly different between crystalloid and colloid after FC in patients with septic shock. Therefore, the timing of fluid responsiveness assessment should be different individually. The assessment time of colloid group may be prolonged to 30 minutes after FC while that of crystal group can be at 10 minute after FC.

Preliminary study of the arm equilibrium pressure to predict the effect of fluid challenge on urine output in oliguric intensive care unit patients / 中华内科杂志

Objective To evaluate whether arm equilibrium pressure (Parm) is helpful to predict the effect of fluid load in improving oliguria in intensive care unit(ICU) patients.Methods Hemodynamically stable patients [mean artery pressure (MAP)＞65 mmHg (1 mmHg=0.133 kPa),heart rate (HR)＜120 beats/min,lactic acid＜2 mmol/L] with urine output (UO)＜0.5 ml· kg-1· h-1 for 3 consecutive hours were enrolled.The fluid loading was performed by infusion of ringer's lactate 500 ml within 30 minute after baseline hemodynamic data were recorded.The positive renal response was defined as UO increased more than 0.5 ml· kg-1 · h-1 1 hour after fluid challenge,otherwise was negative.Results A total of 30 oliguric ICU patients were enrolled including 17 males and 13 females with median age (54.2±16.3) years.After fluid load,patients' HR decreased[(84± 13)beat/min vs.(80± 10) beat/min,P＜0.01],central venous pressure (CVP) increased[(7.0±2.4)mmHg vs.(8.8±2.6) mmHg,P＜0.01],30s Parm [(33.4±5.3) mmHg vs.(35.4±5.8) mmHg,P＜0.01] and 60s Parm [(26.9±4.5) mmHg vs.(28.7±5.0) mmHg,P＜0.01] increased,and UO [(18.5±8.8)ml/h vs.(64.1±38.3)ml/h,P＜0.01] increased significantly,while MAP and lactic acid did not change (P＞0.05).There were eighteen renal responders and 12 patients did not response.In responding group,MAP[(78.1 ±10.7) mmHg vs.(91.2±11.7) mmHg,P＜0.01],30s Parm[(30.4±3.8) mmHg vs.(38.0±3.7) mmHg,P＜0.01]and 60s Parm [(24.3±2.5) mmHg vs.(30.8±4.0) mmHg,P＜0.01] before fluid load were lower than those in negative group.HR,CVP,lactic acid,age and body weight were comparable between two groups (P＞0.05).After volume loading,MAP,30s and 60s Parrn in positive group were still lower than those in negative group (P＜0.05),while HR,CVP and lactic acid were similar (P＞0.05).Correlation analysis showed that baseline 30s Parm (r=-0.75,P＜0.01),60s Parm (r=-0.69,P＜0.01),and MAP (r=-0.46,P＜0.05) were negatively correlated with 1 h UO after fluid load,but HR and CVP were not (P＞0.05).The receiver operating curve (ROC) showed that 30s Parm had the largest area under curve (AUC) of 0.94 (95％ CI 0.84-1.05,P＜0.01),which 35.5 mmHg was the best threshold with sensitivity 94.4％ and specificity 91.7％(likelihood ratio 11.37).Conclusion In hemodynamically stable oliguric ICU patients,if Parm is lower than normal reference value,volume expansion is more likely to increase UO.Thus Parm can be used to predict the effect of fluid loadon UO.

The role of end-tidal carbon dioxide partial pressure in fluid responsiveness assessment in septic shock patient / 中华内科杂志

Objective To assess whether end-tidal carbon dioxide partial pressure (PET CO2) can predict the fluid responsiveness in septic shock patients.Methods Septic shock patients under mechanical ventilation without spontaneous breathing and with the need of a fluid challenge test were included in this study.Heart rate,central venous pressure,pulse pressure,PErCO2,and CI before and after the fluid challenge test were conducted in all the patients.Results Of the 48 septic shock patients included,34 had preload responsiveness,14 had no responsiveness.△CI and △PET CO2 after the fluid challenge test involume responders were (0.85 ± 0.47) L · min-1 · m-2 and (3.5 ± 2.5) mmHg respectively,which were higher than those in no volume responders (P ＜ 0.05).The fluid-induced changes in PET CO2 and CI were correlated (r =0.072,P ＜ 0.05).The AUCRoc of fluid challenge-induced △PET CO2 as the predictor for volume responsiveness was 0.943,and its sensitivity was 87.9％ and specificity was 93.4％ with a critical value of 5％.The AUCRoc of △PP as the predictor for volume responsiveness was 0.801,and its sensitivity was 68.1％ and specificity was 73.2％ with a critical value of 10％.Conclusion The changes of PETCO2 induced by a fluid challenge test can predict fluid responsiveness with reliability,and have a better sensitivity and specificity than the changes of PP.

Choque séptico: Actualización en la monitorización hemodinámica / Septic shock in ICU: update in hemodynamic monitoring

Si bien los principios básicos para el diagnóstico y la monitorización hemodinámica como los pilares terapéuticos del niño con choque séptico se mantienen en el tiempo, es innegable que en las últimas décadas se han incorporado nuevos y trascendentes conceptos, por lo que es importante que el médico tratante de las unidades de cuidados intensivos tenga conocimiento de ellos a cabalidad. La monitorización hemodinámica es una herramienta que no solamente permite detectar el origen de la inestabilidad hemodinámica sino también guiar el tratamiento y evaluar su efectividad. La resucitación con fluidos debe ser el primer paso en la reanimación del paciente hemodinámicamente inestable. Sin embargo, la determinación clínica del volumen intravascular puede ser, en ocasiones, difícil de establecer en el paciente crítico. Las presiones de llenado cardiaco no son capaces de predecir la respuesta a fluidos. Los indicadores dinámicos de respuesta a fluidos evalúan el cambio en el volumen eyectivo durante la ventilación mecánica; de este modo, se valora la curva de Frank-Starling del paciente. Mediante la prueba de fluido es posible evaluar el grado de la reserva de precarga que se puede utilizar para aumentar el volumen eyectivo. En esta revisión se actualiza la información disponible sobre la monitorización hemodinámica básica y funcional.

In recent decades, new and important concepts have emerged for the diagnosis and management of the pediatric patient with septic shock, although the basic principles have remained similar over time. Attending physicians in the pediatric intensive care unit (PICU) must be fully aware of these concepts in order to improve patient care in the critical care unit. Hemodynamic monitoring is a tool that not only allows detection of the source of hemodynamic instability but also guides treatment and assesses its effectiveness. Fluid loading is considered the first step in the resuscitation of hemodynamically unstable patients. Nevertheless, clinical determination of the intravascular volume can be extremely difficult in a critically ill patient. Studies performed have demonstrated that cardiac filling pressures are unable to predict fluid responsiveness. Dynamic tests of volume responsiveness use the change in stroke volume during mechanical ventilation assessing the patients' Frank-Starling curve. Through fluid challenge the clinician can assess whether the patient has a preload reserve that can be used to increase the stroke volume. In this review we updated the available information on basic and functional hemodynamic monitoring.

The value of stroke volume variation in prediction of responsiveness to fluid resuscitation in patients with septic shock / 中华急诊医学杂志

Objective To determine whether stroke volume variation (SVV) in relation to volume loading in mechanically ventilated patients with septic shock.Methods Data of thirty-two mechanically ventilated patients with septic shock admitted from Dec 2009 to May 2012 were prospectively analyzed.Cardiac index (CI),stroke volume (SV),systemic vascular resistance index (SVRI) and stroke volume variation (SVV) were measured by FloTrac/Vigileo before and after fluid resuscitation (250 mL saline in 10 min).Patients with an increase in SV (△SV) ≥ 10％ and ＜ 10％ after fluid volume loading were classified as responders and non-responders,respectively.The comparisons between these two sorts of patients were assessed by using two sample Student' s t-test,and comparisons between changes before and after fluid challenge were assessed by using a paired Student' s t-test.A Pearson' s correlation analysis was employed for evaluate the correlation between △SV and other haemodynamic variables.The roles of SVV,central venous pressure (CVP),mean artery pressure (MAP) and the changes of CVP (△CVP),MAP (△MAP) after fluid administration in predicting volume responsiveness were evaluated by receiver operating characteristic (ROC) curve.Results Thirty-two patients with septic shock were included in this study.There were 54 instances of fluid challenge performed,among which 35 instances were defined as response group.Significantly increased SV induced by fluid challenge was assigned into response group (83.6 ± 15.6) mL vs.(68.5 ± 14.2) mL,P ＜0.01,while in non-response group,there were no significant change in SV (P ＞0.05).SVV was significantly correlated with SV before fluid loading (r =0.522,P ＜ 0.01).The area under the ROC curve (AUC) for stroke volume variation (SVV) was 0.898 (95％ CI:0.796-1.000).Using SVV ≥ 11.5％ as the threshold to predict fluid responsiveness,the sensitivity was 94％ and specificity was 84％.Conclusions SVV can be used to predict fluid responsiveness in patients with septic shock.

Hemodynamic Response to a Rapid Fluid Challenge in End-Stage Liver Disease / 대한마취과학회지

BACKGROUND: Patients with end-stage liver disease have a hyperdynamic circulatory state complicated by a high right ventricular end-diastolic volume index (RVEDVI) and a low ventricular performance. These changes often make if difficult to evaluate volume status and preload. In this study, we analyzed hemodynamic profiles after a rapid fluid challenge in the recipients of a liver transplant. METHODS: Hemodynamic responses were evaluated before and after 200 ml of a 5% albumin challenge in forty patients, recipients of a liver transplant with a Swan-Ganz right-heart ejection fraction oximetry thermodilution cathether. Patients were divided into two groups, group A (responders, n=12, >or= 10% increase in stroke volume index (SVI) after fluid challenge) and group B (non-responders, n = 28, decrease or < 10% increase in SVI after fluid challenge). We analyzed hemodynamic data obtained from the two groups before and after the fluid challenge. RESULTS: Group B had a lower baseline right ventricular ejection fraction (REF) (49.9+/-5.9% vs 42.8+/-5.7%), a higher RVEDVI (120.8+/-19.4 ml/m2 vs 143.6+/-26.3 ml/m2), and a higher right ventricular end-systolic volume index (RVESVI) (60.8+/-14.0 ml/m2 vs 82.8+/-20.5 ml/m2) than group A. In group B, the cardic index (CI) and right ventricular stroke work index (RVSWI) were not increased after the fluid challenge. There was a mild decrease in the mean arterial pressure (MAP) in group B after the fluid challenge. There was a moderate negative correlation between the fluid-induced change in SVI and the baseline RVEDVI in all patients (r =-0.40, P<0.05). CONCLUSIONS: Our study suggests that there is no improvement of hemodynamic profiles after a rapid fluid challenge in many patients with end-stage liver disease, especially those with a high RVEDVI.