Balancing chakras – the passive leg raise

Balancing chakras – the passive leg raise

1075 700 Kat Evans

Balancing Chakras: The passive leg raise

Author & Sketches: Dr Serena Cardosa | Edited by: Dr Kat Evans

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As a medstudent, the topic of fluids eluded me.  When I started working as a junior doctor in the EC this year I had to gain confidence with my fluid resuscitation strategy (and fast!). In this post I will attempt to introduce a simple approach to the basic (albeit challenging) question surrounding fluid resus:

“Does this unstable patient need IV fluids?”

Why do we give a critically ill/septic patient fluids?

The thinking goes: if you fill said patient’s tank you may improve organ perfusion and optimize oxygen delivery & cellular metabolism. By doing this, you may improve the patient’s condition.

We know that only 50% of haemodynamically unstable patients respond to fluids. We also know that sometimes fluids can be harmful, with the potential of causing pulmonary oedema, inflammation, acid/base problems and even increased mortality. One study published in the BMJ, the FEAST trial, found that fluid boluses significantly increased 48-hour mortality in critically ill African children with impaired perfusion. Other studies like the SOAP study demonstrated this too.

So how do we know whether we should give our patients fluids? The answer is found in another question:

Is the patient fluid responsive?  

Remember the Frank Starling principle?

frank starling

Above is the Starling Curve. Imagine the heart is made of elastic bands. When we give a fluid bolus to the heart there is lengthening of the cardiac cells (sarcomeres) during diastole (preload) which results in greater ‘snap-back’/contractility of the heart and a greater volume of blood ejected during systole (cardiac output).

There is a point where the fibrils reach their optimal contractility, and beyond that no amount of fluids/stretching will result in increased cardiac output.

Like an elastic band that you’ve stretched too far, they just don’t bounce back like they used to (i.e. congestive heart failure) in fact they can break.

 Give fluids to ‘fluid responders’

Before we give fluids we want to know if they’re still on the ascending limb of the Starling Curve, where a fluid bolus will result in increased cardiac output/ SV (preload responsive).

frank staling reserve

So how do we tell where on the curve the patient is? Every patient has their own unique Starling Curve. This is why static measures of volume responsiveness like blood pressure, low urine output and CVP measurements only suggest that the patient may be volume depleted. As we don’t know where the patient is on the curve, these single static indices won’t indicate if they are going to be ‘fluid responders’.

That’s why we need something more dynamic to show us how much preload reserve we’ve got. Dynamic measures also look at the interaction between the cardiac and pulmonary systems.

Passive Leg Raise

The passive leg raise (PLR) works in the same way, but instead of giving a potentially detrimental fluid bolus you utilise the blood that had pooled in the legs & splanchnic system as your preload.  It is a diagnostic test, not a treatment modality. It should be performed utilising a cardiac output monitor or arterial line tracing, however in the Ubuntu Hospital setting, non-invasive blood pressure recording used as a surrogate is often the only option.

Benefits:

  • reversible
  • non-invasive
  • easy
  • can be repeated many times without harm.
PLR illustration

Have the patient sitting up on a bed at 45 degrees. Note the MAP. Lower the head of the bed to horizontal & passively raise the legs up to 45 degrees. At 30-90 sec repeat the BP. If the patient is fluid responsive the approximate 300ml bonus you’ve recruited from the legs & abdomen will result in a MAP increase of 10%. Position the patient back and notice reciprocal change.

Basics:

MAP increases >10% with PLR – Patient will likely respond to IV fluid = “Fluid responsive”

MAP does not increase with PLR (or decreases) – Patient will likely NOT respond to IV fluid and may need vasopressors = “Not Fluid responsive”

 

Problems:

  • unreliable in patients with raised intra-abdominal pressure or are severely hypovolaemic (where there isn’t even enough volume in the legs to create a preload bolus)
  • you will have to stop other interventions whilst you do this
  • patients where positional changes are contra-indicated.

Web References

About Dr Serena Cardoso:

 Doctor working in her ‘Community Service Year*’ at a Cape Town Emergency Centre. 

Learning to love Emergency Medicine!

* ‘Community Service Year’ is a 1 year government hospital employment that is required to be completed in South Africa following internship years. Doctors work as independent practitioners & at many areas are the only doctor on duty in an Emergency Centre – this results in a extremely steep learning curve!

References

 
Maitland K1, George EC, Evans JA, Kiguli S, Olupot-Olupot P, Akech SO, Opoka RO, Engoru C, Nyeko R, Mtove G, Reyburn H, Brent B, Nteziyaremye J, Mpoya A, Prevatt N, Dambisya CM, Semakula D, Ddungu A, Okuuny V, Wokulira R, Timbwa M, Otii B, Levin M, Crawley J, Babiker AG, Gibb DM; FEAST trial group. Exploring mechanisms of excess mortality with early fluid resuscitation: insights from the FEAST trial. BMC Med. 2013 Mar 14;11:68. PMID: 23496872.

 
Cavallaro F1, Sandroni C, Marano C, La Torre G, Mannocci A, De Waure C, Bello G, Maviglia R, Antonelli M. Diagnostic accuracy of passive leg raising for prediction of fluid responsiveness in adults: systematic review and meta-analysis of clinical studies. Intensive Care Med. 2010 Sep;36(9):1475-83. PMID: 20502865.

 
Monnet X, Teboul JL. Passive leg raising: five rules, not a drop of fluid! Crit Care. 2015 Jan 14;19:18. PMID: 25658678.
 
Maitland K, Kiguli S, Opoka RO, Engoru C, Olupot-Olupot P, Akech SO, Nyeko R, Mtove G, Reyburn H, Lang T, Brent B, Evans JA, Tibenderana JK, Crawley J, Russell EC, Levin M, Babiker AG, Gibb DM; FEAST Trial Group. Mortality after fluid bolus in African children with severe infection. N Engl J Med. 2011 Jun 30;364(26):2483-95. PMID: 21615299.

 
Monnet X1, Rienzo M, Osman D, Anguel N, Richard C, Pinsky MR, Teboul JL. Passive leg raising predicts fluid responsiveness in the critically ill. Crit Care Med. 2006 May;34(5):1402-7. PMID: 16540963.

 
Jabot J1, Teboul JL, Richard C, Monnet X. Passive leg raising for predicting fluid responsiveness: importance of the postural change. Intensive Care Med. 2009 Jan;35(1):85-90. PMID: 18795254.

 
Boulain T1, Achard JM, Teboul JL, Richard C, Perrotin D, Ginies G. Changes in BP induced by passive leg raising predict response to fluid loading in critically ill patients. Chest. 2002 Apr;121(4):1245-52. PMID: 11948060.

 
Brandt S1, Regueira T, Bracht H, Porta F, Djafarzadeh S, Takala J, Gorrasi J, Borotto E, Krejci V, Hiltebrand LB, Bruegger LE, Beldi G, Wilkens L, Lepper PM, Kessler U, Jakob SM. Effect of fluid resuscitation on mortality and organ function in experimental sepsis models. Crit Care. 2009;13(6):R186. PMID: 19930656.

 
Durairaj L1, Schmidt GA. Fluid therapy in resuscitated sepsis: less is more. Chest. 2008 Jan;133(1):252-63. PMID: 18187750.

 
Hilton AK1, Bellomo R. A critique of fluid bolus resuscitation in severe sepsis. Crit Care. 2012 Jan 25;16(1):302. PMID: 22277834.

 
Malbrain ML1, 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. PMID: 25432556.

Kat Evans

Emergency Medicine Physician in Cape Town, South Africa. Looking for solutions to our unique EM challenges with a quadruple burden of disease.

All stories by:Kat Evans

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Kat Evans

Emergency Medicine Physician in Cape Town, South Africa. Looking for solutions to our unique EM challenges with a quadruple burden of disease.

All stories by:Kat Evans