Preload Dependency of 2D Right Ventricle Speckle Tracking Echocardiography Parameters in Healthy Volunteers: A Prospective Pilot Study

(1) Background: Right ventricular (RV) strain parameters derived from the analysis of the tricuspid annular displacement (TAD) are emergent two-dimensional speckle tracking echocardiography (2D-STE) parameter used for the quantitative assessment of RV systolic function. Few data are available regarding 2D-STE parameters and their dependency on RV preload. Our aim was to evaluate the effect of an acute change in RV preload on 2D-STE parameters in healthy volunteers. (2) Methods: Acute modification of RV preload was performed by a fluid challenge (FC): an infusion of 500 mL of 0.9% sodium chloride was given over 5 min in supine position. Preload dependency (responder group) was confirmed by a stroke volume increase of at least 10% measured by echocardiography. (3) Results: Among 32 healthy volunteers, 19 (59%) subjects were classified as non-responders and 13 (41%) as responders. In the responder group, the tricuspid annular plane systolic excursion (TAPSE) significantly increased (20 (20–23.5) mm to 24 (20.5–26.5) mm; p = 0.018), while RV strain parameters significantly decreased after FC: −23.5 ((−22.3)–(−27.3))% to −25 ((−24)–(29.6))%; p = 0.03) for RV free wall longitudinal strain and −22.8 ((−20.4)–(−30.7))% to −23.7 ((−21.2)–(−27))%; p = 0.02) for RV four-chamber longitudinal strain. 2D-STE parameters derived from the TAD analysis were not influenced by the FC (all p > 0.05). (4) Conclusions: In young, healthy volunteers, RV strain parameters and TAPSE are preload dependent, while TAD parameters were not. The loading conditions must be accounted for when evaluating RV systolic function by 2D-STE parameters.

Transient Myocardial Ischemia in a Case Post Intra-Muscular Adrenaline

Background: Anaphylaxis is a medical emergency and requires immediate medical attention. Kounis syndrome is myocardial infarction or injury occurring in the setting of anaphylaxis and can also be due to the effects of epinephrine. Adrenaline is a common drug in the management of anaphylaxis but the electrocardiographic consequences of its administration post an attack are seldomly seen. Vasospasm is generally the cause for myocardial injury in an acute setting following the administration of epinephrine. Case Presentation: A 21-year- old female developed sudden onset breathlessness and giddiness post vaccination with the oxford –AstraZeneca COVID -19 vaccine. She was administered 0.5 ml adrenaline (1:1000) intramuscularly on the lateral aspect of the left thigh, following which she complained of chest tightness and palpitations. This was accompanied by hypotension and global ST segment depression on her Electrocardiogram. The second electrocardiogram, done after 30 minutes showed a relative resolution in ST segment depressions with sinus rhythm in the one done at 16:00 hours. Creatine Kinase- MB and Troponin I were within normal limits and the patient experienced symptomatic improvement with normalization of blood pressure post fluid challenge. Conclusion: This case report highlights the case of a young female with no comorbidities who developed transient myocardial ischemia after administration of intramuscular adrenalin in therapeutic dose in view of an anaphylactic reaction. The probable action is alpha mediated coronary vasospasm. The potential adverse effects in an acute setting are hence outlined in this case report without discouraging its use given the potential benefits outweigh the risks.

Timing Assessment of Response to Fluid Challenge in Patients with Septic Shock

Objectives: Fluid challenge (FC) is most commonly used for fluid responsiveness (FR) evaluation, with a wide divergence in assessment time choices. Therefore, we aimed to explore the optimal assessment time for FC in patients with septic shock. Methods: A prospective cohort study was conducted. Septic shock patients who had experienced initial resuscitation and required an FC with 500 mL 4% gelatin or normal saline (NS) over 5-10 min were included. FR was defined by an increase in cardiac index (CI) >10%. FR and other predefined variables were recorded at baseline (Tb), immediately (T0), and at 10 (T1), 30 (T2), 45 (T3), 60 (T4), 90 (T5), and 120 (T6) min after FC. The incidence of FR and hemodynamic variables at predefined time points were recorded. Data were analyzed by repeated measures of analysis of variance. Results: 63 patients were enrolled, with 43 in the gelatin group and 20 in the NS group. Among the 45/63 (71%) responders, 31 were responded at T0 (ER), while 14 responded at T1 or later (LR). The proportion of NR, ER and LR was comparable between gelatin and NS groups. After FC, the time course of FR status was slightly different between gelatin and NS groups. In the gelatin group, FC induced most responders (69%, 31/45) and frequency of CI maximum (35%, 11/31) at T2 and sustained a positive FR status until T4; while in the NS group, FC induced most responders (55%, 11/20) and frequency of CI maximum (64%, 9/14) at T1, and sustained FR status until T1. Conclusions: Different time courses of FR were found between gelatin and NS group patients undergoing FC. Thus, when NS is used, FR should be performed within 10 min, while it is better to extend the assessment time to 30 min after FC when gelatin is used.

Dynamic Transesophageal Echocardiographic Parameters for Predicting Fluid Responsiveness in Mechanically Ventilated Patients

Background: The aim was to investigate the feasibility of the dynamic transesophageal echocardiographic parameters to predict fluid responsiveness in mechanically ventilated patients. Methods: In the prospective study, a total of 60 patients scheduled for elective general surgery under mechanical ventilation were enrolled. All patients received 10ml/kg Ringer’s lactate. The data including central venous pressure (CVP), cardiac index (CI), stroke volume variation (SVV), SVC-CI, E velocity, and the ratio of E/e’ was recorded before and after fluid challenge. Patients were classified as Responders (FR group) if their CI increased by at least 15% after fluid challenge. Results: 25/52(48%) were Responders and 27 were non-Responders (52%). The SVC-CI was higher in the Responders (41.90±11.48% vs 28.92±9.05%, P＜0.01). SVC-CI was significantly correlated with △CI (r=0.568, P＜0.01). The area under the ROC curve (AUROC) of SVC-CI was 0.838 (95% CI: 0.728～0.947, P＜0.01) with the optimal cut-off value of 39.4% (sensitivity 64%, specificity 92.6%). The best cut-off value for SVV was 12.5% (sensitivity 40%, specificity 89%) with the AUROC of 0.68 (95% CI 0.53～0.826, P＜0.05). Conclusion: The SVC-CI and SVV can predict fluid responsiveness effectively in mechanically ventilated patients. And SVC-CI is superior in predicting fluid responsiveness compared with SVV. Trial registration: Chinese Clinical Trial Registry, ChiCTR2000034940, Registered 25 July 2020, https://www.chictr.org.cn/index.aspx

Fluid challenge and balloon occlusion testing in patients with atrial septal defects

IntroductionCareful, stepwise assessment is required in all patients with atrial septal defect (ASD) to exclude pulmonary vascular or left ventricular (LV) disease. Fluid challenge and balloon occlusion may unmask LV disease and post-capillary pulmonary hypertension, but their role in the evaluation of patients with ‘operable’ ASDs is not well established.MethodsWe conducted a prospective study in three Italian specialist centres between 2018 and 2020. Patients selected for percutaneous ASD closure underwent assessment at baseline and after fluid challenge, balloon occlusion and both.ResultsFifty patients (46 (38.2, 57.8) years, 72% female) were included. All had a shunt fraction >1.5, pulmonary vascular resistance (PVR) <5 Wood Units (WU) and pulmonary arterial wedge pressure (PAWP) <15 mm Hg. Individuals with a PVR ≥2 WU at baseline (higher PVR group) were older, more symptomatic, with a higher baseline systemic vascular resistance (SVR) than the lower PVR group (all p<0.0001). Individuals with a higher PVR experienced smaller increases in pulmonary blood flow following fluid challenge (0.3 (0.1, 0.5) vs 2.0 (1.5, 2.8) L/min, p<0.0001). Balloon occlusion led to a more marked fall in SVR (p<0.0001) and a larger increase in systemic blood flow (p=0.024) in the higher PVR group. No difference was observed in PAWP following fluid challenge and/or balloon occlusion between groups; four (8%) patients reached a PAWP ≥18 mm Hg following the addition of fluid challenge to balloon occlusion testing.ConclusionsIn adults with ASD without overt LV disease, even small rises in PVR may have significant implications on cardiovascular haemodynamics. Fluid challenge may provide additional information to balloon occlusion in this setting.

Clinical Application of the Fluid Challenge Approach in Goal-Directed Fluid Therapy: What Can We Learn From Human Studies?

Resuscitative fluid therapy aims to increase stroke volume (SV) and cardiac output (CO) and restore/improve tissue oxygen delivery in patients with circulatory failure. In individualized goal-directed fluid therapy (GDFT), fluids are titrated based on the assessment of responsiveness status (i.e., the ability of an individual to increase SV and CO in response to volume expansion). Fluid administration may increase venous return, SV and CO, but these effects may not be predictable in the clinical setting. The fluid challenge (FC) approach, which consists on the intravenous administration of small aliquots of fluids, over a relatively short period of time, to test if a patient has a preload reserve (i.e., the relative position on the Frank-Starling curve), has been used to guide fluid administration in critically ill humans. In responders to volume expansion (defined as individuals where SV or CO increases ≥10–15% from pre FC values), FC administration is repeated until the individual no longer presents a preload reserve (i.e., until increases in SV or CO are &lt;10–15% from values preceding each FC) or until other signs of shock are resolved (e.g., hypotension). Even with the most recent technological developments, reliable and practical measurement of the response variable (SV or CO changes induced by a FC) has posed a challenge in GDFT. Among the methods used to evaluate fluid responsiveness in the human medical field, measurement of aortic flow velocity time integral by point-of-care echocardiography has been implemented as a surrogate of SV changes induced by a FC and seems a promising non-invasive tool to guide FC administration in animals with signs of circulatory failure. This narrative review discusses the development of GDFT based on the FC approach and the response variables used to assess fluid responsiveness status in humans and animals, aiming to open new perspectives on the application of this concept to the veterinary field.