Fluid Administration for Acute Circulatory Dysfunction
Cecconi M, Hernandez G, Dunser M, Antonelli M, Baker T, Bakker J, Duranteau J, Einav S, Groeneveld ABJ, Harris T, Jog S, Machado FR, Mer M, Monge García MI, Myatra SN, Perner A, Teboul JL, Vincent JL, De Backer D. Fluid administration for acute circulatory dysfunction using basic monitoring: narrative review and expert panel recommendations from an ESICM task force. Intensive Care Med. 2018 Nov 19. doi: 10.1007/s00134-018-5415-2. PMID: 30456467.
Acute circulatory dysfunction can occur in every hospital setting (ICU, Emergency department, general wards). Consequently, fluid resuscitation is commonly started outside ICUs, and the quality of the initial management may affect patient prognosis. However, there is paucity of data regarding best fluid management in pre-ICU settings, and there is significant heterogeneity in clinical practice of fluid administration. 
An ESICM task force produced a review and expert panel recommendation,  describing the clinical variables which can be used to detect circulatory failure, and how to define and conduct fluid-challenges (FC), what are FC triggers and safety endpoints. The review has a special focus on low-intensity monitoring within hospitals and resource-limited settings.
Clinical assessment has a pivotal role in identifying circulatory dysfunction and should combine haemodynamic data (blood pressure and heart rate) with windows on tissue perfusion (oliguria, altered mentation, and skin changes). Increased lactate levels are a hallmark of shock, and experts recommend measuring lactate levels whenever possible, along with clinical evaluation. An important trial is ongoing to demonstrate whether peripheral perfusion is superior to lactate level to target haemodynamic resuscitation .
STUDY STRENGTHS & LIMITATIONS
In overt fluid loss, tachycardia and hypotension can be used as indicators of hypovolemia and should prompt fluid loading. However, the review demonstrates how several haemodynamic variables, including blood pressure, heart rate and central venous pressure among others, are neither sensitive nor specific when used alone to guide fluid resuscitation in patients with haemodynamic failure. Similarly, index of tissue perfusion, such as urinary output and capillary refilling time, may be influenced by factors other than haemodynamic status, and should not be considered alone.
Fluid challenges are specific haemodynamic test aimed to improve tissue perfusion, and their volume should be large enough to raise the mean systemic filling pressure and venous return (which equals cardiac output), even with transitory effect, to identify fluid responsiveness. The authors recommend using 150-350 ml (4 ml/kg) in 15 min, looking for real-time changes in the clinical haemodynamic variables which trigger the fluid challenge, acknowledging the limitation of these variables.
The authors propose a summary of statements (reported in Table 1 in the article), which summarise the best available evidence or expert recommendation, and conclude that further studies should address research gaps in fluid administration in pre-ICU or limited resource settings.
TAKE HOME MESSAGE
- A thorough clinical examination (including evaluation of mentation, skin abnormalities and oliguria), together with heart rate and blood pressure and lactate level, should be used to identify patients with acute circulatory dysfunction
- Fluid loading, defined as the rapid administration of a large amount of fluids, is recommended in the presence of overt hypovolemia, which should be avoided in the absence of overt hypovolemia (apart from septic shock)
- A fluid-challenge is a test of the cardio-circulatory system, evaluating whether the patient has a preload reserve that can be used to increase cardiac output. The authors suggest infusing 4 ml/kg in <15 min, targeting an improvement in the triggering variables.
This article review was prepared and submitted by Dr Massimiliano Greco, Department of Anaesthesia and Intensive Care Medicine, Humanitas Clinical & Research Centre, Milan (Italy), on behalf of the ESICM Journal Review Club
1) Cecconi M, Hofer C, Teboul JL, et al; Fluid challenges in intensive care: the FENICE study: A global inception cohort study. Intensive Care Med. 2015 Sep;41(9):1529-37.
2) Cecconi M, Hernandez G, Dunser M et al:. Fluid administration for acute circulatory dysfunction using basic monitoring: narrative review and expert panel recommendations from an ESICM task force. Intensive Care Med. 2018 Nov 19.
3) Hernandez G, Cavalcanti AB, Ospina‑Tascon G, et al. Early goal‑directed therapy using a physiological holistic view: the ANDROMEDA‑SHOCK‑a randomized controlled trial. Ann Intensive Care 8:52