Left ventricular longitudinal strain variations assessed by speckle-tracking echocardiography after a passive leg raising maneuver in patients with acute circulatory failure to predict fluid responsiveness: A prospective, observational study

Background An association was reported between the left ventricular longitudinal strain (LV-LS) and preload. LV-LS reflects the left cardiac function curve as it is the ratio of shortening over diastolic dimension. The aim of this study was to determine the sensitivity and specificity of LV-LS variations after a passive leg raising (PLR) maneuver to predict fluid responsiveness in intensive care unit (ICU) patients with acute circulatory failure (ACF). Methods Patients with ACF were prospectively included. Preload-dependency was defined as a velocity time integral (VTI) variation greater than 10% between baseline (T0) and PLR (T1), distinguishing the preload-dependent (PLD+) group and the preload-independent (PLD-) group. A 7-cycles, 4-chamber echocardiography loop was registered at T0 and T1, and strain analysis was performed off-line by a blind clinician. A general linear model for repeated measures was used to compare the LV-LS variation (T0 to T1) between the two groups. Results From June 2018 to August 2019, 60 patients (PLD+ = 33, PLD- = 27) were consecutively enrolled. The VTI variations after PLR were +21% (±8) in the PLD+ group and -1% (±7) in the PLD- group (p<0.01). Mean baseline LV-LS was -11.3% (±4.2) in the PLD+ group and -13.0% (±4.2) in the PLD- group (p = 0.12). LV-LS increased in the whole population after PLR +16.0% (±4.0) (p = 0.04). The LV-LS variations after PLR were +19.0% (±31) (p = 0.05) in the PLD+ group and +11.0% (±38) (p = 0.25) in the PLD- group, with no significant difference between the two groups (p = 0.08). The area under the curve for the LV-LS variations between T0 and T1 was 0.63 [0.48–0.77]. Conclusion Our study confirms that LV-LS is load-dependent; however, the variations in LV-LS after PLR is not a discriminating criterion to predict fluid responsiveness of ICU patients with ACF in this cohort.

Comparison of mean systemic pressure in patients with acute circulatory failure receiving passive leg raising vs. pneumatic leg compression

Background: Driving pressure of venous return (VR) is determined by a pressure gradient between mean systemic pressure (Pms) and central venous pressure (CVP). While passive leg raising (PLR) and pneumatic leg compression PC (PC) can increase VR, no study has explored the effects of these two procedures on Pms and VR-related hemodynamic variables. Methods: Forty patients with acute circulatory failure were enrolled in this analysis. All patients obtained both PLR and PC, and were measured for Pms, CVP, mean arterial pressure (MAP), cardiac output (CO), VR resistance (RVR), and systemic vascular resistance (SVR) at baseline and immediately after procedures. To minimize carry over effect, the patients were divided in 2 groups based on procedure sequence which were 1) patients receiving PLR first then PC (PLR-first), and 2) patients receiving PC first then PLR (PC-first). Both groups waited for a washout period before performing the 2 second procedure. Primary outcome was difference in Pms between PLR and PC procedures. Secondary outcome were differences in CVP, MAP, CO, RVR, and SVR between PLR and PC procedures. Results: No difference was found in baseline characteristics and no carry over effect was observed between the 2 groups of patients. Compared with baseline, both PLR and PC significantly increased Pms, CVP, MAP, and CO. PLR increased Pms (9.0±2.3 vs 4.8±1.7 mmHg, p<0.001), CVP (4.5±1.2 vs. 1.6±0.7 mmHg, p<0.001), MAP (22.5±5.6 vs. 14.4±5.0 mmHg, p<0.001), and CO (1.5±0.5 vs. 0.5±0.2 L/min, p<0.001) more than PC. However, PC, also significantly increased RVR (16 ± 27.2 dyn.s/cm5, p=0.001) and SVR (78.4 ± 7.2 dyn.s/cm5, p<0.001) but no difference in PLR group. Conclusion: Among patients with acute circulatory failure, PLR increased Pms, CVP, MAP, and CO more than PC.

Comparison of mean systemic pressure in patients with acute circulatory failure receiving passive leg raising vs. pneumatic leg compression

Background: Driving pressure of venous return (VR) is determined by a pressure gradient between mean systemic pressure (Pms) and central venous pressure (CVP). While passive leg raising (PLR) and pneumatic leg compression PC (PC) can increase VR, no study has explored the effects of these two procedures on Pms and VR-related hemodynamic variables. Methods: Forty patients with acute circulatory failure were enrolled in this analysis. All patients obtained both PLR and PC, and were measured for Pms, CVP, mean arterial pressure (MAP), cardiac output (CO), VR resistance (RVR), and systemic vascular resistance (SVR) at baseline and immediately after procedures. To minimize carry over effect, the patients were divided in 2 groups based on procedure sequence which were 1) patients receiving PLR first then PC (PLR-first), and 2) patients receiving PC first then PLR (PC-first). Both groups waited for a washout period before performing the 2 second procedure. Primary outcome was difference in Pms between PLR and PC procedures. Secondary outcome were differences in CVP, MAP, CO, RVR, and SVR between PLR and PC procedures. Results: No difference was found in baseline characteristics and no carry over effect was observed between the 2 groups of patients. Compared with baseline, both PLR and PC significantly increased Pms, CVP, MAP, and CO. PLR increased Pms (9.0±2.3 vs 4.8±1.7 mmHg, p<0.001), CVP (4.5±1.2 vs. 1.6±0.7 mmHg, p<0.001), MAP (22.5±5.6 vs. 14.4±5.0 mmHg, p<0.001), and CO (1.5±0.5 vs. 0.5±0.2 L/min, p<0.001) more than PC. However, PC, also significantly increased RVR (16 ± 27.2 dyn.s/cm5, p=0.001) and SVR (78.4 ± 7.2 dyn.s/cm5, p<0.001) but no difference in PLR group. Conclusion: Among patients with acute circulatory failure, PLR increased Pms, CVP, MAP, and CO more than PC.

Changes in Cardiac Index Induced by Unilateral Passive Leg Raising: a Novel Way for Assessing Fluid Responsiveness

Background: To evaluate the fluid responsiveness of patients, we examined the change in cardiac index (CI) during a unilateral passive leg raising (PLR) test using the ProAQT/Pulsioflex. In addition, we compared the change of CI triggered by bilateral PLR test and unilateral PLR test, and the ability to estimate volume responsiveness in patients.Methods: This was a prospective, observational study, and we enrolled 40 individuals thought of volume expansion. The data of cardiac index, stroke variation in volume, stroke volume index, along with variation in pulse pressure were obtained with ProAQT/Pulsioflex at a semi-recumbent position, during unilateral PLR, bilateral PLR, as well as after expansion of volume (500 ml saline over 15 min). If CI improved more than 15% to the expansion of volume, patients were defined as responders.Results: We excluded three patients. We found that a unilateral PLR-triggered CI increment ≥7.455% forecasted a fluid-triggered CI increment ≥15% with 77.27% sensitivity and 83.33% specificity. Meanwhile, bilateral PLR-triggered increases in CI ≥9.8% forecasted a fluid-triggered CI increment ≥15% with 95.45% sensitivity and 77.78% specificity. The area under the ROC curves constructed for unilateral and bilateral PLR-triggered changes in CI was not significantly different (p=0.1544).Conclusions: The change of CI induced by unilateral PLR may estimate volume responsiveness in patients.Trial registration: Unilateral passive leg raising test to assess patient volume responsiveness: Single-Center Observational Clinical Study, ChiCTR2100046762. Registered 28 May 2021, https://www.chictr.org.cn/edit.aspx?pid=127104&htm=4

Effect of positive end-expiratory pressure value on change in end-tidal carbon dioxide as a predictor of fluid responsiveness in Patients Undergoing Passive Leg Raising Maneuver

Identification of patients’ fluid status in the emergency room should be made before giving fluid therapy. This study aimed to determine the effect of positive end-expiratory pressure on change in end-tidal carbon dioxide during passive leg raising maneuver to predict fluid responsiveness. Thirty subjects aged 18-65 years in the resuscitation room, all on the ventilator, were divided into three groups according to their positive end-expiratory pressure value: low (0-5 cmH2O), moderate (6-10 cmH2O), and high (>10 cmH2O). Every subject underwent passive leg raising to simulate fluid administration. Values of blood pressure, heart rate, cardiac output, and end-tidal carbon dioxide were recorded before and after the maneuver. Analysis of the three groups found a significant correlation between change in end-tidal carbon dioxide with a cut-off value of 5% and 1 mmHg with fluid responsiveness of subjects in the low (p = 0.028) and moderate (p = 0.013) but not in the high positive end-expiratory pressure group (p = 0.333). In conclusion, change in end-tidal carbon dioxide in mechanically ventilated patients undergoing passive leg raising maneuvers can be used as a predictor of fluid responsiveness, but this method cannot be used on patients with high positive end-expiratory pressure (> 10 cmH2O) Keywords : change in end tidal carbon dioxide, fluid responsiveness, positive end-expiratory pressure, passive leg raising, cardiac output surrogateCorrespondence : [email protected]

Comparison of Mean Systemic Pressure in Patients with Acute Circulatory Failure Receiving Passive Leg Raising vs. Pneumatic Leg Compression.

Background: Driving pressure of venous return (VR) is determined by mean systemic pressure (Pms) and central venous pressure (CVP). While passive leg raising (PLR) and pneumatic leg compression PC (PC) can increase VR, there is no study explore the effects of these two procedures on Pms and VR-related hemodynamic variables.Methods: Forty patients with acute circulatory failure were included in this analysis. All patients were performed both PLR and PC, and were measured for Pms, CVP, mean arterial pressure (MAP), cardiac output (CO), VR resistance (RVR), and systemic vascular resistance (SVR) at baseline and immediately after procedures. To minimized carry-on effect, the patients were divided into 2 groups based on procedure sequence which were 1) the patients who received PLR first then PC (PLR-first), and 2) the patients who received PC first then PLR (PC-first). Both groups were waited for washing period before performed 2nd procedure. Primary outcome was difference in Pms between PLR and PC procedure. Secondary outcome were differences in CVP, MAP, CO, RVR, and SVR between PLR and PC procedure.Results: There was no difference in baseline characteristics and no carry-on effect between 2 groups of patients. Compared to baseline, both PLR and PC significantly increased Pms, CVP, MAP, and CO. Compared to PC, PLR more increased Pms (9.0±2.3 vs 4.8±1.7 mmHg, p<0.001), CVP (4.5±1.2 vs. 1.6±0.7 mmHg, p<0.001), MAP (22.5±5.6 vs. 14.4±5.0 mmHg, p<0.001), and CO (1.5±0.5 vs. 0.5±0.2 L/min, p<0.001). PC, but not PLR also significantly increased RVR (16 ± 27.2 dyn.s/cm5, p=0.001) and SVR (78.4 ± 7.2 dyn.s/cm5, p<0.001) .Conclusion: In patients with acute circulatory failure, PLR more increased Pms, CVP, MAP, and CO than PC.

Early Effects of Passive Leg-Raising Test, Fluid Challenge, and Norepinephrine on Cerebral Autoregulation and Oxygenation in COVID-19 Critically Ill Patients

Background: Coronavirus disease 2019 (COVID-19) patients are at high risk of neurological complications consequent to several factors including persistent hypotension. There is a paucity of data on the effects of therapeutic interventions designed to optimize systemic hemodynamics on cerebral autoregulation (CA) in this group of patients.Methods: Single-center, observational prospective study conducted at San Martino Policlinico Hospital, Genoa, Italy, from October 1 to December 15, 2020. Mechanically ventilated COVID-19 patients, who had at least one episode of hypotension and received a passive leg raising (PLR) test, were included. They were then treated with fluid challenge (FC) and/or norepinephrine (NE), according to patients' clinical conditions, at different moments. The primary outcome was to assess the early effects of PLR test and of FC and NE [when clinically indicated to maintain adequate mean arterial pressure (MAP)] on CA (CA index) measured by transcranial Doppler (TCD). Secondary outcomes were to evaluate the effects of PLR test, FC, and NE on systemic hemodynamic variables, cerebral oxygenation (rSo2), and non-invasive intracranial pressure (nICP).Results: Twenty-three patients were included and underwent PLR test. Of these, 22 patients received FC and 14 were treated with NE. The median age was 62 years (interquartile range = 57–68.5 years), and 78% were male. PLR test led to a low CA index [58% (44–76.3%)]. FC and NE administration resulted in a CA index of 90.8% (74.2–100%) and 100% (100–100%), respectively. After PLR test, nICP based on pulsatility index and nICP based on flow velocity diastolic formula was increased [18.6 (17.7–19.6) vs. 19.3 (18.2–19.8) mm Hg, p = 0.009, and 12.9 (8.5–18) vs. 15 (10.5–19.7) mm Hg, p = 0.001, respectively]. PLR test, FC, and NE resulted in a significant increase in MAP and rSo2.Conclusions: In mechanically ventilated severe COVID-19 patients, PLR test adversely affects CA. An individualized strategy aimed at assessing both the hemodynamic and cerebral needs is warranted in patients at high risk of neurological complications.