Fourth Surviving Sepsis Campaign's hemodynamic recommendations: a step forward or a return to chaos?

End-expiratory Occlusion Test and Mini-fluid Challenge Test for Predicting Fluid Responsiveness in Acute Circulatory Failure

Introduction

Predicting which patients with acute circulatory failure will respond to the fluid by an increase in cardiac output is a daily challenge. End-expiratory occlusion test (EEOT) and mini-fluid challenge (MFC) can be used for assessing fluid responsiveness in patients with spontaneous breathing activity, cardiac arrhythmias, low-tidal volume and/or low lung compliance.

Methods

The objective of the study is to evaluate the value of EEOT and MFC-induced rise in left ventricular outflow tract (LVOT) velocity time integral (VTI) in predicting fluid responsiveness in acute circulatory failure in comparison to the passive leg-raising (PLR) test. Hundred critically ill ventilated and sedated patients with acute circulatory failure were studied. LVOT VTI was measured by transthoracic echocardiography before and after EEOT (interrupting the ventilator at end-expiration over 15 s), and before and after MFC (100 ml of Ringer lactate was infused over 1 min). The variation of LVOT VTI after EEOT and the MFC was calculated from the baseline. Sensitivity, specificity, and area under the receiver-operating characteristic (AUROC) curve of LVOT VTI after EEOT and MFC to predict fluid responsiveness were determined.

Results

After PLR, stroke volume (SV) increased by ≥12% in 49 patients, who were defined as responders and 34 patients in whom the increase in SV <12% were defined as nonresponders. A cutoff of 9.1% Change in VTI after MFC (ΔVTIMFC) predicted fluid responsiveness with an AUROC of 0.96 (P < 0.001) with sensitivity and specificity of 91.5% and 88.9%, respectively. Change in VTI after EEOT (ΔVTIEEOT) >4.3% predicted fluid responsiveness with sensitivity and specificity 89.4% and 88.9%, respectively, with an AUROC of 0.97 (P < 0.001), but in 17 patients, EEOT was not possible because triggering of the ventilator by the patient's inspiratory effort.

Conclusion

In conclusion, in mechanically ventilated patients with acute circulatory failure Δ VTIMFC and Δ VTI EEOT accurately predicts fluid responsiveness.

Doppler-estimated Carotid and Brachial Artery Flow as Surrogate for Cardiac Output: Needs Further Validation

Selvam V, Srinivasan S. Doppler-estimated Carotid and Brachial Artery Flow as Surrogate for Cardiac Output: Needs Further Validation. Indian J Crit Care Med 2022;26(2):159-160.

The Impact of Choice Architecture on Sepsis Fluid Resuscitation Decisions: An Exploratory Survey-Based Study

Background

Discordance with well-known sepsis resuscitation guidelines is often attributed to rational assessments of patients at the point of care. Conversely, we sought to explore the impact of choice architecture (i.e., the environment, manner, and behavioral psychology within which options are presented and decisions are made) on decisions to prescribe guideline-discordant fluid volumes.

Design

We conducted an electronic, survey-based study using a septic shock clinical vignette. Physicians from multiple specialties and training levels at an academic tertiary-care hospital and academic safety-net hospital were randomized to distinct answer sets: control (6 fluid options), time constraint (6 fluid options with a 10-s limit to answer), or choice overload (25 fluid options). The primary outcome was discordance with Surviving Sepsis Campaign fluid resuscitation guidelines. We also measured response times and examined the relationship between each choice architecture intervention group, response time, and guideline discordance.

Results

A total of 189 of 624 (30.3%) physicians completed the survey. Time spent answering the vignette was reduced in time constraint (9.5 s, interquartile range [IQR] 7.3 s to 10.0 s, P < 0.001) and increased in choice overload (56.8 s, IQR 35.9 s to 86.7 s, P < 0.001) groups compared with control (28.3 s, IQR 20.0 s to 44.6 s). In contrast, the relative risk of guideline discordance was higher in time constraint (2.07, 1.33 to 3.23, P = 0.001) and lower in choice overload (0.75, 0.60, to 0.95, P =0.02) groups. After controlling for time spent reading the vignette, the overall odds of choosing guideline-discordant fluid volumes were reduced for every additional second spent answering the vignette (OR 0.98, 0.97, to 0.99, P < 0.001).

Conclusions

Choice architecture may affect fluid resuscitation decisions in sepsis regardless of patient conditions, warranting further investigation in real-world contexts. These effects should be considered when implementing practice guidelines.

Highlights

Current use of vasopressors in septic shock

Background

Vasopressors are commonly applied to restore and maintain blood pressure in patients with sepsis. We aimed to evaluate the current practice and therapeutic goals regarding vasopressor use in septic shock as a basis for future studies and to provide some recommendations on their use.

Methods

From November 2016 to April 2017, an anonymous web-based survey on the use of vasoactive drugs was accessible to members of the European Society of Intensive Care Medicine (ESICM). A total of 17 questions focused on the profile of respondents, triggering factors, first choice agent, dosing, timing, targets, additional treatments, and effects of vasopressors. We investigated whether the answers complied with current guidelines. In addition, a group of 34 international ESICM experts was asked to formulate recommendations for the use of vasopressors based on 6 questions with sub-questions (total 14).

Results

A total of 839 physicians from 82 countries (65% main specialty/activity intensive care) responded. The main trigger for vasopressor use was an insufficient mean arterial pressure (MAP) response to initial fluid resuscitation (83%). The first-line vasopressor was norepinephrine (97%), targeting predominantly a MAP > 60–65 mmHg (70%), with higher targets in patients with chronic arterial hypertension (79%). The experts agreed on 10 recommendations, 9 of which were based on unanimous or strong (≥ 80%) agreement. They recommended not to delay vasopressor treatment until fluid resuscitation is completed but rather to start with norepinephrine early to achieve a target MAP of ≥ 65 mmHg.

Conclusion

Reported vasopressor use in septic shock is compliant with contemporary guidelines. Future studies should focus on individualized treatment targets including earlier use of vasopressors.

Prediction of fluid responsiveness in ventilated patients

Fluid administration is the first-line therapy in patients with acute circulatory failure. The main goal of fluid administration is to increase the cardiac output and ultimately the oxygen delivery. Nevertheless, the decision to administer fluids or not should be carefully considered, since half of critically ill patients are fluid unresponsive, and the deleterious effects of fluid overload clearly documented. Thus, except at the initial phase of hypovolemic or septic shock, where hypovolemia is constant and most of the patients responsive to the initial fluid resuscitation, it is of importance to test fluid responsiveness before administering fluids in critically ill patients. The static markers of cardiac preload cannot reliably predict fluid responsiveness, although they have been used for decades. To address this issue, some dynamic tests have been developed over the past years. All these tests consist in measuring the changes in cardiac output in response to the transient changes in cardiac preload that they induced. Most of these tests are based on the heart-lung interactions. The pulse pressure or stroke volume respiratory variations were first described, following by the respiratory variations of the vena cava diameter or of the internal jugular vein diameter. Nevertheless, all these tests are reliable only under strict conditions limiting their use in many clinical situations. Other tests such as passive leg raising or end-expiratory occlusion act as an internal volume challenge. To reliably predict fluid responsiveness, physicians must choose among these different dynamic tests, depending on their respective limitations and on the cardiac output monitoring technique which is used. In this review, we will summarize the most recent findings regarding the prediction of fluid responsiveness in ventilated patients.

Fluid resuscitation during early sepsis: a need for individualization

The prognosis of septic shock is tightly linked to the earliness of both appropriate antibiotic therapy and early hemodynamic resuscitation. This latter is essentially based on fluid and vasopressors administration. The step-by-step strategy, called "early goal-directed therapy" (EGDT) developed in 2001 and endorsed by the Surviving Sepsis Campaign (SSC) between 2004 and 2016 is no longer recommended. Indeed, recent multicenter randomized clinical trials showed no reduction in all-cause mortality, duration of organ support and in-hospital length of stay with EGDT in comparison with standard care. The most recent SCC guidelines have dropped the original EGDT by deleting the central venous pressure and the central venous oxygen saturation from the recommendations. Dynamic variables of fluid responsiveness are now recommended to be used after an initial fluid infusion of a fixed volume (30 mL/kg) during the first three hours of resuscitation. However, this approach is also questionable due to the lack of individualization at the early and crucial phase of resuscitation. In this review, we propose a more personalized approach for the early and later phases of fluid resuscitation during sepsis.

The crashing patient: hemodynamic collapse

PURPOSE OF REVIEW

Rapid restoration of tissue perfusion and oxygenation are the main goals in the resuscitation of a patient with circulatory collapse. This review will focus on providing an evidence based framework of the technological and conceptual advances in the evaluation and management of the patient with cardiovascular collapse.

RECENT FINDINGS

The initial approach to the patient in cardiovascular collapse continues to be based on the Ventilate-Infuse-Pump rule. Point of care ultrasound is the preferred modality for the initial evaluation of undifferentiated shock, providing information to narrow the differential diagnosis, to assess fluid responsiveness and to evaluate the response to therapy. After the initial phase of resuscitative fluid administration, which focuses on re-establishing a mean arterial pressure to 65 mmHg, the use of dynamic parameters to assess preload responsiveness such as the passive leg raise test, stroke volume variation, pulse pressure variation and collapsibility of the inferior vena cava in mechanically ventilated patients is recommended.

SUMMARY

The crashing patient remains a clinical challenge. Using an integrated approach with bedside ultrasound, dynamic parameters for the evaluation of fluid responsiveness and surrogates of evaluation of tissue perfusion have made the assessment of the patient in shock faster, safer and more physiologic.