Fluid overload is detrimental

OVERVIEW

• De-resuscitation specifically refers to ‘Late Goal Directed Fluid Removal (LGFR)’, which involves “aggressive and active fluid removal by means of diuretics and renal replacement therapy with net ultrafiltration”.
• De-resuscitation is also sometimes used to more loosely refer to the the phase of critical illness and/or the care of a critically ill patient, after initial resuscitation and stabilisation. It is characterised by the discontinuation of invasive therapies and a transition to a negative fluid balance.
• Late conservative fluid management (LCFM) is defined as two consecutive days of negative fluid balance within the first week of ICU stay, and is an independent predictor of survival in ICU patients.

POSITIVE FLUID BALANCE

• Positive fluid balance is a state of fluid overload resulting from fluid administration during resuscitation and subsequent therapies
• Fluid overload is defined by “a cut off value of 10% of fluid accumulation as this is associated with worse outcomes”
• Percentage of fluid accumulation can be defined “by dividing the cumulative fluid balance in litre by the patient’s baseline body weight and multiplying by 100%”

Positive fluid balance is associated with worse morbidity and mortality in multiple studies:

• worse overall mortality in critically ill patients (recent systematic review)
• increased mortality in patients with acute kidney injury (AKI) (SOAP study)
• prolonged recovery in patients with acute lung injury/ acute respiratory distress syndrome (ALI/ARDS) (FACTT trial)
• worse mortality in septic shock patients (VAST trial)
• worse morbidity in colorectal surgery patients
• associated with intra-abdominal hypertension

PATHOPHYSIOLOGICAL EFFECTS OF FLUID OVERLOAD 

The kidneys are susceptible to functional impairment due to positive fluid balance

• postive fluid balance causes interstitial edema and intrabdominal hypertension
• these effects impair kidney function and cause oliguria
• thus positive fluid balance counteracts its own resolution

THE “ROSE” CONCEPT OF PHASES OF CRITICAL ILLNESS

Resuscitation phase (R)

• Salvage or rescue treatment with fluids administered quickly as a bolus (4 mL kg-1 over 10 to 15 minutes)
• The goal is early adequate goal directed fluid management (EAFM), fluid balance must be positive and the suggested resuscitation targets are:
  MAP > 65 mm Hg, CI > 2.5 L min-1.m-2, PPV < 12%, LVEDAI > 8 cm.m-2.

Optimisation phase (O)

• occurs within hours
• ischaemia and reperfusion
• degree of positive fluid balance may be marker of severity in this phase
• risk of polycompartment syndrome
• unstable, compensated shock state requiring titrating of fluids to cardiac output
• Targets: MAP > 65 mm Hg , CI > 2.5 L min-1.m-2, PPV < 14%, LVEDAI 8−12 cm-1.m-2, IAP (< 15 mm Hg ) is monitored and APP (> 55 mm Hg ) is calculated. Preload optimised with GEDVI 640—800 mL.m-2

Stabilisation phase (S)

• evolves over days
• fluid therapy only for normal and replacement
• absence of shock or threat of shock
• Monitor daily body weight, fluid balanmaintenance ce and organ function
• Targets: neutral or negative fluid balance; EVLWI < 10−12 mL.kg-1 PBW, PVPI < 2.5, IAP < 15 mm Hg , APP > 55 mm Hg , COP > 16−18 mm Hg , and CLI < 60

Evacuation phase (E)

• patients who do not transition from the ‘ebb’ phase of shock to the ‘flow’ phase after the ‘2nd hit’ develop global increased permeability syndrome (GIPS)
• fluid overload casues end-organ dysfunction
• requires late goal directed fluid removal (“de-resuscitation”) to achieve negative fluid balance
• need to avoid over enthusiastic fluid removal resulting in hypovolaemia

DE-RESUSCITATION

Recommendations

• “a goal of a zero to negative fluid balance by day 3 and to keep the cumulative fluid balance on day 7 as low as possible (Grade 2B)”
• “diuretics or renal replacement therapy (in combination with albumin) can be used to mobilise fluids in haemodynamically stable patients with intra-abdominal hypertension and a positive cumulative fluid balance after the acute resuscitation has been completed and the inciting issues/source control have been addressed (Grade 2D)”

The ‘PAL’ approach

• high PEEP for 30 minutes (at least equal to intrabdominal pressure) – to drive fluid from the alveoli into the interstitium, then
• Albumin administration (e.g. 2 x 100 mL 20% albumin over 60 minutes on Day 1, then titrated to albumin >30 g/L) – to pull fluid from the interstitium into the circulation
• Frusemide (‘Lasix’) infusion started 60 minutes after albumin at 60 mg/h for 4 hors, then titrated between5 and 20 mg/h to maintain >100 mL/h urine output
• Use of this approach in patients with “acute lung injury” as part of a pilot study was associated with a negative fluid balance, a reduction of EVLWI and IAP, and decreased duration of mechanical ventilation without compromising organ function.

References and Links

• Bouchard J, Mehta RL. Fluid balance issues in the critically ill patient. Contrib Nephrol. 2010;164:69-78. [pubmed]
• Cordemans C, De Laet I, Van Regenmortel N, et al. Aiming for a negative fluid balance in patients with acute lung injury and increased intra-abdominal pressure: a pilot study looking at the effects of PAL-treatment. Ann Intensive Care. 2012;2 Suppl 1:S15. [pubmed] [free full text]
• Gonzalez F, Vincent F. The fluid balance in the critically ill patients: what are we talking about? Minerva Anestesiol. 2011;77:(8)766-7. [pubmed]
• Malbrain ML, Marik PE, Witters I, Cordemans C, Kirkpatrick AW, Roberts DJ, Van Regenmortel N. Fluid overload, de-resuscitation, and outcomes in critically ill or injured patients: a systematic review with suggestions for clinical practice. Anaesthesiol Intensive Ther. 2014 Nov-Dec;46(5):361-80. doi: 10.5603/AIT.2014.0060. [pubmed] [free full text]