Fluid resuscitation in ICU patients: quo vadis?

Fluid challenges in operating room: A planned sub study of the Fluid Day observational study

BACKGROUND

Intraoperative fluid administration is a ubiquitous intervention in surgical patients. But inadequate fluid administration may lead to poor postoperative outcomes. Fluid challenges (FCs), in or outside the so-called goal-directed fluid therapy, allows testing the cardiovascular system and the need for further fluid administration. Our primary aim was to evaluate how anesthesiologists conduct FCs in the operating room in terms of type, volume, variables used to trigger a FC and to compare the proportion of patients receiving further fluid administration based on the response to the FC.

METHODS

This was a planned substudy of an observational study conducted in 131 centres in Spain in patients undergoing surgery.

RESULTS

A total of 396 patients were enrolled and analysed in the study. The median [interquartile range] amount of fluid given during a FC was 250ml (200-400). The main indication for FC was a decrease in systolic arterial pressure in 246 cases (62.2%). The second was a decrease in mean arterial pressure (54.4%). Cardiac output was used in 30 patients (7.58%), while stroke volume variation in 29 of 385 cases (7.32%). The response to the initial FC did not have an impact when prescribing further fluid administration.

CONCLUSIONS

The current indication and evaluation of FC in surgical patients is highly variable. Prediction of fluid responsiveness is not routinely used, and inappropriate variables are frequently evaluated for assessing the hemodynamic response to FC, which may result in deleterious effects.

[Pathophysiology of septic shock]

Sepsis and septic shock result from an inadequate host response to an infection, which causes organ dysfunction. The progression of this condition is manifested by the occurrence of successive clinical stages, resulting from the systemic inflammatory response secondary to the activation of different inflammatory mediators, leading to organ dysfunction. There is a high burden of evidence on the role of endotoxin in the pathogenesis of sepsis and its crucial role in triggering the inflammatory response in sepsis caused by gram-negative bacteria. The coagulation cascade activation in sepsis patients is part of the host's adaptive immune response to infection. The endothelium is the main target in sepsis, which is metabolically active and can.

Comparison of Superior Vena Cava and Inferior Vena Cava Diameter Changes by Echocardiography in Predicting Fluid Responsiveness in Mechanically Ventilated Patients

Context:

Resuscitation of critically ill patients requires an accurate assessment of the patient's intravascular volume status. Passive leg raise cause auto transfusion of fluid to the thoracic cavity.

Aims:

This study aims to assess and compare the efficacy of superior vena cava (SVC) and inferior vena cava (IVC) diameter changes in response to passive leg raise (PLR) in predicting fluid responsiveness in mechanically ventilated hemodynamically unstable critically ill patients.

Methods:

We enrolled 30 patients. Predictive indices were obtained by transesophageal and transthoracic echocardiography and were calculated as follows: (Dmax − Dmin)/Dmax for collapsibility index of SVC (cSVC) and (Dmax − Dmin)/Dmin for distensibility index of IVC (dIVC), where Dmax and Dmin are the maximal and minimal diameters of SVC and IVC. Measurements were performed at baseline and 1 min after PLR. Patients were divided into responders (increase in cardiac index (CI) ≥10%) and nonresponders (NR) (increase in CI <10% or no increase in CI).

Results:

Among those included, 24 (80%) patients were R and six were NR. There was significant rise in mean arterial pressure, decrease in heart rate, and decrease in mean cSVC from baseline to 1 min after PLR among responders. The best threshold values for discriminating R from NR was 35% for cSVC, with sensitivity and specificity of being 100%, and 25% for dIVC, with 54% sensitivity and 86.7% specificity. The areas under the receiver operating characteristic curves for cSVC and dIVC regarding the assessment of fluid responsiveness were 1.00 and 0.66, respectively.

Conclusions:

cSVC had better sensitivity and specificity than dIVC in predicting fluid responsiveness.

Cardiovascular clusters in septic shock combining clinical and echocardiographic parameters: a post hoc analysis

PURPOSE

Mechanisms of circulatory failure are complex and frequently intricate in septic shock. Better characterization could help to optimize hemodynamic support.

METHODS

Two published prospective databases from 12 different ICUs including echocardiographic monitoring performed by a transesophageal route at the initial phase of septic shock were merged for post hoc analysis. Hierarchical clustering in a principal components approach was used to define cardiovascular phenotypes using clinical and echocardiographic parameters. Missing data were imputed.

FINDINGS

A total of 360 patients (median age 64 [55; 74]) were included in the analysis. Five different clusters were defined: patients well resuscitated (cluster 1, n = 61, 16.9%) without left ventricular (LV) systolic dysfunction, right ventricular (RV) failure or fluid responsiveness, patients with LV systolic dysfunction (cluster 2, n = 64, 17.7%), patients with hyperkinetic profile (cluster 3, n = 84, 23.3%), patients with RV failure (cluster 4, n = 81, 22.5%) and patients with persistent hypovolemia (cluster 5, n = 70, 19.4%). Day 7 mortality was 9.8%, 32.8%, 8.3%, 27.2%, and 23.2%, while ICU mortality was 21.3%, 50.0%, 23.8%, 42.0%, and 38.6% in clusters 1, 2, 3, 4, and 5, respectively (p < 0.001 for both).

CONCLUSION

Our clustering approach on a large population of septic shock patients, based on clinical and echocardiographic parameters, was able to characterize five different cardiovascular phenotypes. How this could help physicians to optimize hemodynamic support should be evaluated in the future.

Indications for fluid resuscitation in patients with septic shock: Post-hoc analyses of the CLASSIC trial

BACKGROUND

Fluid resuscitation is recommended in septic shock, but the specific indications for fluids have not been established. Our aim was to investigate the indications currently used for fluid resuscitation and the effect of fluid on these indications in patients with septic shock admitted to the intensive care unit (ICU).

METHODS

This was a post-hoc analysis of the CLASSIC trial, where patients with septic shock were randomized to fluid restriction or standard care. We recorded indications for and effect of each fluid bolus during the first 24 hours.

RESULTS

In total, 256 fluid boluses were administered on 515 indications to the 76 patients in the standard care group. The most frequent indications were low blood pressure/increase in noradrenalin dose (199 boluses, 78%), high lactate (94, 37%), and low urinary output (68, 27%). While the analyses of all 418 fluid boluses given in all 151 patients failed to show any effect of fluid on these variables, the data did suggest that time from randomization altered the effect; fluid may have increased urinary output when given early and increased noradrenalin dose when given later. For 56% of the fluid boluses given on the most frequent indications, a second fluid bolus was given on the same indication.

CONCLUSIONS

In ICU patients with septic shock, low blood pressure, high lactate, and low urinary output were the most frequent indications for fluid. The effects of fluids when given on these indications were less clear, but may dependent on the time course of sepsis resuscitation.

Restricting volumes of resuscitation fluid in adults with septic shock after initial management: the CLASSIC randomised, parallel-group, multicentre feasibility trial

PURPOSE

We assessed the effects of a protocol restricting resuscitation fluid vs. a standard care protocol after initial resuscitation in intensive care unit (ICU) patients with septic shock.

METHODS

We randomised 151 adult patients with septic shock who had received initial fluid resuscitation in nine Scandinavian ICUs. In the fluid restriction group fluid boluses were permitted only if signs of severe hypoperfusion occurred, while in the standard care group fluid boluses were permitted as long as circulation continued to improve.

RESULTS

The co-primary outcome measures, resuscitation fluid volumes at day 5 and during ICU stay, were lower in the fluid restriction group than in the standard care group [mean differences -1.2 L (95 % confidence interval -2.0 to -0.4); p < 0.001 and -1.4 L (-2.4 to -0.4) respectively; p < 0.001]. Neither total fluid inputs and balances nor serious adverse reactions differed statistically significantly between the groups. Major protocol violations occurred in 27/75 patients in the fluid restriction group. Ischaemic events occurred in 3/75 in the fluid restriction group vs. 9/76 in the standard care group (odds ratio 0.32; 0.08-1.27; p = 0.11), worsening of acute kidney injury in 27/73 vs. 39/72 (0.46; 0.23-0.92; p = 0.03), and death by 90 days in 25/75 vs. 31/76 (0.71; 0.36-1.40; p = 0.32).

CONCLUSIONS

A protocol restricting resuscitation fluid successfully reduced volumes of resuscitation fluid compared with a standard care protocol in adult ICU patients with septic shock. The patient-centred outcomes all pointed towards benefit with fluid restriction, but our trial was not powered to show differences in these exploratory outcomes.

TRIAL REGISTRATION

NCT02079402.

Associations of Hospital and Patient Characteristics with Fluid Resuscitation Volumes in Patients with Severe Sepsis: Post Hoc Analyses of Data from a Multicentre Randomised Clinical Trial

PURPOSE

Fluid resuscitation is a key intervention in patients with sepsis and circulatory impairment. The recommendations for continued fluid therapy in sepsis are vague, which may result in differences in clinical practice. We aimed to evaluate associations between hospital and patient characteristics and fluid resuscitation volumes in ICU patients with severe sepsis.

METHODS

We explored the 6S trial database of ICU patients with severe sepsis needing fluid resuscitation randomised to hydroxyethyl starch 130/0.42 vs. Ringer's acetate. Our primary outcome measure was fluid resuscitation volume and secondary outcome total fluid input administered from 24 hours before randomisation until the end of day 3 post-randomisation. We performed multivariate analyses with hospital and patient baseline characteristics as covariates to assess associations with fluid volumes given.

RESULTS

We included 654 patients who were in the ICU for 3 days and had fluid volumes available. Individual trial sites administered significantly different volumes of fluid resuscitation and total fluid input after adjusting for baseline variables (P<0.001). Increased lactate, higher cardiovascular and renal SOFA subscores, lower respiratory SOFA subscore and surgery were all independently associated with increased fluid resuscitation volumes.

CONCLUSIONS

Hospital characteristics adjusted for patient baseline values were associated with differences in fluid resuscitation volumes given in the first 3 days of severe sepsis. The data indicate variations in clinical practice not explained by patient characteristics emphasizing the need for RCTs assessing fluid resuscitation volumes fluid in patients with sepsis.