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Three Part Question

In [patients with severe head injury and low blood pressure] is [hypertonic saline better than isotonic fluids] at [increasing cerebral perfusion, reducing intracranial pressure and improving outcome]?

Clinical Scenario

You are resuscitating a 30 year old male with a severe closed head injury. His GCS was 3 on admission. He is intubated and ventilated and a CT scan is being organised. His blood pressure is only 90/40mmHg. You want to improve cerebral perfusion by giving IV fluid but are aware that too much fluid might worsen cerebral oedema. You wonder whether there would be any advantage in giving hypertonic saline.

Search Strategy

Medline 1966-10/03 using the OVID interface.
[exp hypertonic solutions/ or exp saline solution, hypertonic/ or "hypertonic saline".mp.] AND [exp craniocerebral trauma/ OR "head injury".mp. OR "HEAD INJURIES".mp. OR exp head injuries, closed/ OR "head injured".mp. OR exp brain injuries/ OR "brain injury".mp.]

Search Outcome

66 papers were found of which 3 were trials of sufficient quality that addressed the three part question. These are displayed in the table.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Wade CE et al, 1997, Sweden	223 patients with severe head injuries and hypotension. 250ml 7.5% NaCl / 6% Dextran 70 (single bolus) vs standard care (usually Ringer's Lactate)	Cohort analysis from six previous PRCTs	24 hour survival	Odds ratio of 1.92 (p=0.06) for survival 24 hours with HS	Hetrogeneous trials, which were not all designed to assess head injured patients Long term outcome not assessed
			Discharge Survival	Odds ratio of 2.12 (p=0.048) for survival until discharge with HS
Shackford SR et al, 1998, USA	34 patients with severe head injuries and undergoing ICP monitoring. 1.6% NaCl (HS) vs Ringer's lactate (RL) to treat "episodes of haemodynamic instability" during initial resuscitation and for 5 days.	PRCT	ICP	No significant difference between groups. Maximum ICP fell 9.1 mmHg with HS and rose 2.5mmHg with RL (p<0.05)	CPP not addressed HS group had more severe injuries Small numbers: a power study indicated the need for 320 patients but only 34 were enrolled
			Number of interventions to control elevated ICP	Average of 31 interventions per patient with HS vs 11 interventions with RL (p<0.01)
			Glasgow Outcome Score at discharge	No significant difference
Simma B et al, 1998, Switzerland	32 children with severe head injury and ICP monitoring. 1.6% NaCl (HS) vs Ringer's lactate (RL) as only IV fluid for 3 days following injury.	PRCT	ICP and CPP	No significant difference	Small numbers: the power calculation was directed towards detecting a difference in ICP ICP elevations treated by stepwise increase therapy, thus not surprising that no difference in ICP seen
			Number of interventions to control elevated ICP	Average of 44 interventions per patient with HS vs 62 per patient with RL. (p<0.02)
			Na concentration and ICP	Inverse correlation (p<0.3) in both groups
			Na concentration and CPP	Inverse correlation significant only in HS group after 8 hours (p=0.002) otherwise N/S
			Length of ICU stay	Shorter ICU stay: 11.6 vs 8.0 days (p=0.04)
			Complications	Higher incidence in RL group (N/S)
			Ventilation times	Longer duration in RL group (N/S)
			Length of hospital stay	No significant difference
			Survival	No significant difference

Comment(s)

All three trials showed some improvements in patients with head injury treated with hypertonic saline compared with standard care. The largest showed a two times survival advantage in those treated with hypertonic saline but this was a cohort analysis rather than a PRCT. It is not established how much hypertonic saline should be given and when. A large randomised controlled trial would help to establish the role of hypertonic saline.

Clinical Bottom Line

There is insufficient evidence at present to justify the use of hypertonic saline as resuscitation fluid in patients with severe head injury.

References

1. Wade CE, Grady JJ, Kramer GC et al. Individual patient cohort analysis of the efficacy of hypertonic saline/dextran in patients with traumatic brain injury and hypotension. J Trauma 1997;42(5 Suppl):S61-5.
2. Shackford SR, Bourguignon PR, Wald SL et al. Hypertonic saline resuscitation of patients with head injury: a prospective, randomized clinical trial. J Trauma 1998;44(1):50-8.
3. Simma B, Burger R, Falk M et al. A prospective, randomized and controlled study of fluid management in children with severe head injury: lactated Ringer's solution versus hypertonic saline. Crit Care Med 1998;26(7):1265-70.