Pre-hospital initiation of fluid replacement therapy in trauma

The Assessment Report identified 2 Health Technology Assessment reports of the cost effectiveness of pre-hospital IV fluid replacement from an NHS perspective.

The first study, published in 1998, assessed the cost and effectiveness of treatment of trauma patients by paramedics, compared with treatment by EMTs.

The additional cost of paramedic treatment (costs associated with trauma-related ALS training, salary and additional pre-hospital interventions) was presented per paramedic crew and per call out. The average unit cost of the ALS crew at £2.44 per minute was similar to the cost of a BLS crew at £2.43 per minute. There was an increase of £3 in the call out cost of an ALS crew (average of £81.08 per ALS call out) compared with a BLS crew call out (average of £78.02), because ALS crews spent more time at the scene. The total costs (pre-hospital and hospital costs combined) were also estimated. There was a non-significant increase of £22 in the average total costs for patients attended by a paramedic-crewed ambulance (£2,231 per patient, compared with £2,209 per patient attended by EMTs alone). Between 20% and 30% of the cost of paramedic training and salary was attributed to trauma. However, reductions in the level of trauma-related training had little effect on the overall cost of training.

The second study was conducted alongside an RCT (discussed in section 4.3) in which paramedics were randomised to different resuscitation protocols (pre-hospital IV fluid versus no pre-hospital fluid) to evaluate the cost effectiveness of pre-hospital IV fluid therapy.

Although there was no difference in the median ambulance call-out time of 55 minutes, there was a 2-minute increase in the mean call-out time associated with pre-hospital IV fluid replacement. Costs were presented as initial costs (ambulance costs, consumables, and accident and emergency costs) and total costs (which also included inpatient costs). The cost of pre-hospital IV fluid replacement was higher (but not significantly higher) than that of delayed fluid replacement, by £3 in the initial phase of treatment (£419 compared with £416) and by £28 overall (£2,706 compared with £2,678).

The Assessment Report did not include an economic model because it was considered that there was insufficient evidence on the effectiveness of IV fluid replacement therapy to inform such a model, and because the additional costs associated with pre-hospital IV fluid therapy, such as consumables and paramedic training, were thought to be minor – particularly because paramedics would be required to stock IV fluid and to undergo training in cannulation and IV fluid administration for the treatment of non-trauma patient groups. Adherence to a conservative pre-hospital IV fluid policy could, however, increase ambulance efficiency to a small extent by improving response times.

The Committee reviewed the evidence, including the views of experts, on the clinical and cost effectiveness of IV fluid administered in a pre-hospital setting. In its considerations, the Committee was mindful of the need to take account of the effective use of NHS resources.

The Committee considered that there was some evidence of benefit associated with delaying the initiation of IV fluid until hospital arrival.

The Committee considered the extent to which evidence from the most methodologically sound RCT, which demonstrated a benefit in delaying IV fluid resuscitation in penetrating injuries, could be generalised to blunt injuries. The Committee heard, however, that the trial was based on the administration of larger quantities of IV fluid than would now be considered appropriate, and that it was, therefore, difficult to generalise the results to current clinical practice. In the absence of high-quality evidence on effectiveness, the Committee considered that guidance should take into account professional consensus, although the Institute did not formally evaluate the Consensus Statement and JRCALC guidelines.

The Committee heard from experts that it would not be clinically appropriate to withdraw the use of IV fluid in a pre-hospital setting. The experts emphasised that there was a small proportion of severely hypovolaemic trauma patients at high risk of immediate death who might benefit from pre-hospital initiation of IV fluid therapy; they explained that the aim of IV fluid in these circumstances is to prevent further circulatory collapse without attempting to restore circulating volume fully back to normal or to achieve normal physiology.

The Committee considered how these patients with severe hypovolaemic shock should best be identified and treated. The Committee heard that there are a number of physiological indicators of haemorrhagic shock such as pallor, tachycardia and capillary refill time, although the most readily available physiological measure was considered to be the absence of a palpable radial pulse. The Committee understood that presence or absence of a radial pulse has been used as an approximate guide to whether the systolic blood pressure is above or below 80 mmHg to 90 mmHg but that this is not fully validated. The Committee concluded, therefore, that IV fluid should be administered in the pre-hospital setting only if a radial pulse (or a central pulse, in penetrating injuries of the torso) is not palpable. The Committee was persuaded that in the presence of severe hypovolaemia, which is considered to be immediately life threatening, clinical judgement as to the best course of action would be required.

The experts further advised the Committee that consideration should be given to how well the haemorrhage is controlled. Haemorrhages can be described as controlled (for example, by external pressure applied to a wound), self-limiting (for example, bleeding from a closed femoral fracture), potentially uncontrolled (when the bleeding has stopped but might start again if the blood pressure increased, and the injury is at a site where applying pressure would not stop the bleeding), or uncontrolled. The Committee heard that the risks associated with administration of IV fluid are different for controlled and uncontrolled haemorrhage, and it may be difficult to distinguish between these types of haemorrhage in the pre-hospital setting. Patients with severe uncontrolled bleeding with circulatory collapse are at risk of immediate cardiac arrest and death from extreme hypovolaemia/exsanguination. But the experts also highlighted that in patients with uncontrolled or potentially uncontrolled bleeding, vigorous fluid therapy may exacerbate bleeding by diluting blood clotting factors, reducing the concentration of circulating blood platelets, and by dislodging early clots forming at the site of haemorrhage. In patients with controlled or self-limiting bleeding, the infusion of IV fluid may help to restore tissue perfusion without exacerbating bleeding.

Taking these factors into account, the Committee considered that a pragmatic approach would be to withhold IV fluid if the signs of shock are not marked. If the signs of shock are more severe (as illustrated by an absent radial pulse) administering IV fluid may prevent extreme hypovolaemia with its risk of producing organ damage and cardiac arrest. The experts advised that giving small volumes in this situation (and repeating, if necessary) may keep the patient alive without unduly exacerbating the bleeding, even if the bleeding is uncontrolled or potentially uncontrolled. The Committee concluded that IV fluid should be administered according to the above criteria in boluses of no more than 250 ml and should normally be started en route to hospital to avoid delays at the scene. This agrees with the recommendations in the Consensus Statement; the revised JRCALC guidelines (due in 2004) are also expected to include this recommendation. The Committee also concluded that administration of the first bolus should be followed by reassessment and administration of further boluses until a radial pulse (or a central pulse in penetrating injuries of the torso) becomes palpable. The Committee was advised that good patient-handling techniques in pre-hospital care were essential to minimise the risk of continued haemorrhage before the administration of IV fluid.

The treatment of trauma in patients with isolated closed head injury was not considered in detail by the Committee because it fell outside the remit of this appraisal. However, the Committee heard from experts that consideration should be given to trauma patients with multiple injuries in whom both haemorrhagic shock and head injury might coexist. Altered consciousness in trauma may be indicative of severe haemorrhagic shock or of head injury, and it may be difficult to distinguish between the 2 in the pre-hospital setting. There was concern that if IV fluid was withheld from trauma patients with multiple injuries including head injury, this might have a deleterious effect on the outcome of the head injury because of low perfusion of the brain. The Committee considered cautious administration of IV fluid (with 250 ml boluses titrated against the presence of a radial pulse, with reassessment) was appropriate for trauma patients with uncontrolled bleeding and concomitant head injury in the same way as other hypovolaemic trauma patients.

Experts advised that the guidance should take into account factors – such as the patient being trapped – that might delay arrival at hospital. The Committee concluded that there was inadequate evidence on which to base recommendations on the use of IV fluid in these circumstances. It was appreciated, however, that in these circumstances, other emergency procedures would be initiated that fall outside the remit of this guidance.

On the balance of the evidence on the relative effectiveness of crystalloid and colloid solutions administered in the pre-hospital setting, the Committee was persuaded that the merits of different IV fluid types should be based on cost and risk of adverse events. Crystalloid solutions are not associated with the hypersensitivity reactions seen in some patients when colloids are infused, and they are less expensive than colloid solutions. The Committee therefore considered intravenous infusion with crystalloid solutions to be the preferred option. On balance of the evidence on the relative effectiveness of different crystalloids, the Committee considered normal saline, which has the lowest cost, to be the favoured option.

Consideration was given to the use of pre-hospital IV fluid in young children and infants. The Committee heard from the experts that children, particularly those younger than 8 years, should be considered as a separate group because their physiology is different and different methods are needed to assess hypovolaemic shock. The experts advised that it would not be appropriate to use the absence of a radial pulse or an increased heart rate, in isolation, as criteria to determine whether pre-hospital IV fluid should be administered. The Committee discussed in detail both the available evidence and the experts' views on the appropriate use of IV fluid in the pre-hospital setting for young children and infants. In the absence of adequate evidence and any professional consensus, the Committee considered that they were unable to make specific recommendations for this group. However, they concluded that transfer to hospital should not be delayed in order that IV fluid can be administered.

The Committee considered the issue of training for those administering pre-hospital IV fluid therapy, and concluded that only healthcare professionals with appropriate training in ALS techniques and pre-hospital care should administer IV fluid therapy to trauma patients in the pre-hospital setting.

The Committee noted that the information available on cost effectiveness was poor. The Committee considered the costs associated with the IV fluid used for pre-hospital administration to be minimal. It also considered that costs associated with paramedic training would be unchanged regardless of whether IV fluid is administered for trauma in a pre-hospital setting, because all paramedics should have undergone the necessary training as part of routine preparation for pre-hospital care. The Committee concluded that, although the costs associated with pre-hospital IV fluid administration were minimal, there was an opportunity cost to be considered in terms of potential improvements in response times, throughput, and overall efficiency as a result of longer call-out times when IV fluid therapy was administered.