HYPOTENSIVE RESUSCITATION

Hypotensive Resuscitation

Daniel Stretton

PGC Critical Care

Evidence for and against a strategy of Hypotensive Resuscitation

Introduction

Hypotensive resuscitation techniques have been adopted by the Joint Royal Colleges Ambulance Liaison Committee (JRCALC) and have been subsequently written into the UK ambulance service clinical practice guidelines (JRCALC Clinical Practice Guidelines 2006). There bears little reference to its beginnings and the methodology behind such practice. Specifically there is no difference in treatment between patients presenting with penetrating trauma or blunt trauma. Hypotensive resuscitation therefore is indicated for all forms of haemorrhagic shock, but is there sufficient evidence to support such a radical treatment regime for a broad group of patients.

As a course of treatment used with hypotensive resuscitation JRCALC have adopted crystalloid solution (Compound Sodium Lactate/Sodium Chloride) as there fluid of choice, however West Midlands Ambulance Service Paramedics have only 0.9% Sodium Chloride at their disposal. Would the limitation of fluid type have a negative impact on mortality rates in this patient group, and are there comparative reviews available to recommend better fluid types or the need for Compound Sodium Lactate for Paramedics in West Midlands Ambulance Service when practicing hypotensive resuscitation.

To summarise the following statement best describes current practice and will form the basis for critical analysis of evidence and form recommendations for any change in practice required.

Hypovolaemic patients should all be treated with hypotensive resuscitation techniques and circulating volumes maintained with 0.9% Sodium Chloride.

Definition of hypotensive resuscitation

The concept of hypotensive resuscitation in the literature is clear; however, how much of which fluid to which endpoint (MAP or other) should be given is not defined precisely. Walter B Cannon is credited with the first proposal of deliberate hypotension (controlled hypotension) as a mechanism to reduce internal haemorrhage during uncontrolled haemorrhage before control of bleeding vessels is achieved.11 There are two possible strategies in trauma: 1. Delayed resuscitation, where the hypotensive period is deliberately prolonged by withholding fluid therapy until operative intervention achieves definitive haemostasis, or 2. Permissive hypotension, where fluid is given but the endpoint for resuscitation is lower than normotension (normotension is defined as a MAP of 80 mm Hg or higher). In practical terms, these two approaches may be combined and adjusted to meet the needs of the individual patient, so that the differences between them are not clearly defined. In a review of emergency procedures performed by UK paramedics, 23% of resuscitation protocols were based on hypotensive resuscitation principles.

Background

A definition of hypotensive resuscitation is “where all kinds of therapy are commenced including fluid therapy, thereby increasing systemic pressure without, however, reaching normotension” (Kreimeier, 2002, 787-99).

Hypotensive resuscitation is not a new concept, it was first recognised as a beneficial form of treatment during the First World War. Published as a paper in 1918, Walter Cannon and John Fraser explained how the use of fluid resuscitation as a preventative treatment against wound shock actually increased mortality rates, there proposal was to cause deliberate hypotension to ensure haemorrhage was kept to a minimum until surgical control of the haemorrhage could be gained (Cannon, Fraser, ...