Introduction
Elevated intracranial pressure (ICP) represents the most important cause of morbidity and mortality in patients suffering from severe traumatic head injury. Early management of the elevated intracranial pressure is advantageous in preventing secondary brain insults and improving outcome. Infusion of hyperosmolar solutes is one of the modalities currently used for management of intracranial hypertension after severe head injury. Mannitol 20% is considered as the reference solute, but it has limitations and may fail to decrease critically elevated intracranial pressure. Hypertonic saline solutions have received renewed attention in clinical practice as osmotic agent for cerebral resuscitation. It may be more beneficial than other osmotic diuretics because they augment intravascular volume and cardiovascular performance in addition to reducing intracranial tension and improving cardiovascular elastance.
This study compares the effect of 20% isovolume of mannitol with 7.5% hypertonic saline on intracranial pressure (ICP), hemodynamics and cardiac performance in patients with severe head injury and high intracranial pressure.
Methods
Fifty-six patients admitted to intensive care unit fulfilling the inclusion criteria were allocated randomly into two groups. Group (A), 28 patients, received a bolus dose infusion of 2 ml/kg mannitol 20% within 10 minutes and group (B), 28 patients, received a bolus dose infusion of 2ml/kg hypertonic saline 7.5% within 10 minutes. Extradural catheter tip pressure transducer was inserted in all patients. Central venous catheter and urinary catheter were also inserted. Continuous monitoring of ICP was done for all patients and data of first 12 hours was recorded. Measurement of hemodynamic variables (HR, BP, and CVP) and cardiac output variables (CI, SVI, and EF) were assessed through transthoracic electrical bioimpedance using BOMED NNCCOM3 cardiodynamic apparatus at different time intervals after infusion of the tested solution. Urine output and blood electrolytes were also evaluated. Number of additional doses of the tested solution was recorded.
Results
Both groups were similar regarding sex, age, and GCS at admission. There was significant decrease in ICP after 30 minutes and one hour after infusion in both groups (from 21±2.5 to 9±2.25 and 8±1 mmHg in HTS group and from 21±1.8 to 8±1.75 and 9±1.05 mmHg in mannitol group). Furthermore, in HTS group, there was significant increase in cardiac index (CI), stroke volume index (SVI), and ejection fraction (EF). There was also mild, but insignificant, increase in mean arterial pressure and central venous pressure (CVP). Heart rate showed non-significant decrease. On the other hand, in mannitol group, there was a significant decrease in CVP, while all other cardiac and hemodynamic variables showed no significant changes.
Discussion
HTS 7.5% is effective in reducing ICP to the same extent when compared to mannitol but for longer duration of action. Furthermore, HTS 7.5% has the advantages of maintaining hemodynamics and improving cardiac performance. So we recommend that HTS 7.5% may take place of mannitol in early management of severe head trauma patients with increased intracranial pressure especially when hemodynamic instability is present.
Figure 1.
Changes in Intracranial pressure (ICP) at different time intervals among study groups.
Figure 2.
Changes in cardiac index (CI) at different time intervals among study groups.
Figure 3.
Changes in Stroke volume index (SVI) at different time intervals among study groups.
Figure 4.
Changes in Ejection Fraction (EF %) at different time intervals among study groups.
Figure 5.
Changes in central venous pressure (CVP) at different time intervals among study groups.
References
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