Analysis of the response to therapeutic measures to reduce intracranial pressure in head injured patients

Comparison of Intracranial Pressure Measurements Before and After Hypertonic Saline or Mannitol Treatment in Children With Severe Traumatic Brain Injury

IMPORTANCE

Hyperosmolar agents are cornerstone therapies for pediatric severe traumatic brain injury. Guideline recommendations for 3% hypertonic saline (HTS) are based on limited numbers of patients, and no study to date has supported a recommendation for mannitol.

OBJECTIVES

To characterize current use of hyperosmolar agents in pediatric severe traumatic brain injury and assess whether HTS or mannitol is associated with greater decreases in intracranial pressure (ICP) and/or increases in cerebral perfusion pressure (CPP).

DESIGN, SETTING, AND PARTICIPANTS

In this comparative effectiveness research study, 1018 children were screened and 18 were excluded; 787 children received some form of hyperosmolar therapy during the ICP-directed phase of care, with 521 receiving a bolus. Three of these children were excluded because they had received only bolus administration of both HTS and mannitol in the same hour, leaving 518 children (at 44 clinical sites in 8 countries) for analysis. The study was conducted from February 1, 2014, to September 31, 2017, with follow-up for 1 week after injury. Final analysis was performed July 20, 2021.

INTERVENTIONS

Boluses of HTS and mannitol were administered.

MAIN OUTCOMES AND MEASURES

Data on ICP and CPP were collected before and after medication administration. Statistical methods included linear mixed models and corrections for potential confounding variables to compare the 2 treatments.

RESULTS

A total of 518 children (mean [SD] age, 7.6 [5.4] years; 336 [64.9%] male; 274 [52.9%] White) were included. Participants' mean (SD) Glasgow Coma Scale score was 5.2 (1.8). Bolus HTS was observed to decrease ICP and increase CPP (mean [SD] ICP, 1.03 [6.77] mm Hg; P < .001; mean [SD] CPP, 1.25 [12.47] mm Hg; P < .001), whereas mannitol was observed to increase CPP (mean [SD] CPP, 1.20 [11.43] mm Hg; P = .009). In the primary outcome, HTS was associated with a greater reduction in ICP compared with mannitol (unadjusted β, -0.85; 95% CI, -1.53 to -0.19), but no association was seen after adjustments (adjusted β, -0.53; 95% CI, -1.32 to 0.25; P = .18). No differences in CPP were observed. When ICP was greater than 20 mm Hg, greater than 25 mm Hg, or greater than 30 mm Hg, HTS outperformed mannitol for each threshold in observed ICP reduction (>20 mm Hg: unadjusted β, -2.51; 95% CI, -3.86 to -1.15, P < .001; >25 mm Hg: unadjusted β, -3.88; 95% CI, -5.69 to -2.06, P < .001; >30 mm Hg: unadjusted β, -4.07; 95% CI, -6.35 to -1.79, P < .001), with results remaining significant for ICP greater than 25 mm Hg in adjusted analysis.

CONCLUSIONS AND RELEVANCE

In this comparative effectiveness research study, bolus HTS was associated with lower ICP and higher CPP, whereas mannitol was associated only with higher CPP. After adjustment for confounders, both therapies showed no association with ICP and CPP. During ICP crises, HTS was associated with better performance than mannitol.

Acute management of acquired brain injury part I: an evidence-based review of non-pharmacological interventions

PRIMARY OBJECTIVE

To review the literature on non-pharmacological interventions used in acute settings to manage elevated intracranial pressure (ICP) and minimize cerebral damage in patients with acquired brain injury (ABI).

MAIN OUTCOMES

A literature search of multiple databases (CINAHL, EMBASE, MEDLINE and PSYCHINFO) and hand-searched articles covering the years 1980-2008 was performed. Peer reviewed articles were assessed for methodological quality using the PEDro scoring system for randomized controlled trials (RCTs) and the Downs and Black tool for RCTs and non-randomized trials. Levels of evidence were assigned and recommendations made.

RESULTS

Five non-invasive interventions for acute ABI management were assessed: adjusting head posture, body rotation (continuous rotational therapy and prone positioning), hyperventilation, hypothermia and hyperbaric oxygen. Two invasive interventions were also reviewed: cerebrospinal fluid (CSF) drainage and decompressive craniectomy (DC).

CONCLUSIONS

There is a paucity of information regarding non-pharmacological acute management of patients with ABI. Strong levels of evidence were found for only four of the seven interventions (decompressive craniectomy, cerebrospinal fluid drainage, hypothermia and hyperbaric oxygen) and only for specific components of their use. Further research into all interventions is warranted.

Emergency treatment options for pediatric traumatic brain injury

Traumatic brain injury is a leading killer of children and is a major public health problem around the world. Using general principles of neurocritical care, various treatment strategies have been developed to attempt to restore homeostasis to the brain and allow brain healing, including mechanical factors, cerebrospinal fluid diversion, hyperventilation, hyperosmolar therapies, barbiturates and hypothermia. Careful application of these therapies, normally in a step-wise fashion as intracranial injuries evolve, is necessary in order to attain maximal neurological outcome for these children. It is hopeful that new therapies, such as early hypothermia or others currently in preclinical trials, will ultimately improve outcome and quality of life for children after traumatic brain injury.

Dose response to cerebrospinal fluid drainage on cerebral perfusion in traumatic brain-injured adults

OBJECT

Intracranial hypertension remains a common complication of traumatic brain injury (TBI). Ventriculostomy drainage is a recommended therapy to decrease intracranial pressure (ICP), but little empirical evidence exists to guide treatment. The authors conducted a study to examine systematically the effect of cerebral spinal fluid (CSF) drainage on ICP and indices of cerebral perfusion.

METHODS

Intracranial pressure, cerebral perfusion pressure (CPP), cerebral blood flow velocity (CBFV), and near-infrared spectroscopy-determined regional cerebral oxygenation (rSO2) were measured in 58 patients (with Glasgow Coma Scale scores < or = 8) before, during, and after ventriculostomy drainage. Three randomly ordered CSF drainage protocols varied in the volume of CSF removed (1 ml, 2 ml, and 3 ml). Physiological variables were time averaged in 1-minute blocks from baseline to 10 minutes after cessation of ventricular drainage. There was a significant dose-time interaction for ICP with the three-extraction volume protocol, with incremental decreases in ICP (F [20, 1055] = 6.10; p = 0.0001). There was a significant difference in the CPP depending on the amount of CSF removed (F [2, 1787] = 3.22; p = 0.040) and across time (F [10, 9.58] = 11.9; p = 0.0003) without a significant dose-time interaction. A 3-ml withdrawal of CSF resulted in a 10.1% decrease in ICP and a 2.2% increase in CPP, which were sustained for 10 minutes. There was no significant dose, time or dose-time interaction with CBFV or rSO2.

CONCLUSIONS

Cerebrospinal fluid drainage (3 ml) significantly reduced ICP and increased CPP for at least 10 minutes. Analysis of these findings supports the use of ventriculostomy drainage as a means of at least temporarily reducing elevated ICP in patients with TBI.

The effect of cerebrospinal fluid drainage on cerebral perfusion in traumatic brain injured adults

Cerebrospinal fluid drainage is a first line treatment used to manage severely elevated intracranial pressure (> or = 20 mm Hg) and improve outcomes in patients with acute head injury. There is no consensus regarding the optimal method of cerebrospinal fluid removal. The purpose of this investigation was to determine whether cerebrospinal fluid drainage decreases intracranial pressure and improves cerebral perfusion and to identify factors that impact treatment effectiveness. This study involved 31 severely head injured patients. Intracranial pressure and other indices of cerebral perfusion (cerebral perfusion pressure, cerebral blood flow velocity, and regional cerebral oximetry) were measured before, during, and after cerebrospinal fluid drainage. Arterial and jugular venous oxygen content was measured before and after cerebrospinal fluid drainage. Patients underwent three randomly ordered cerebrospinal fluid drainage protocols that varied in the volume of cerebrospinal fluid removed (1 mL, 2 mL, and 3 mL) for a total of 6 mL of cerebrospinal fluid removed. There was a significant change in the intracranial pressure from a mean at baseline of 26.1 mm Hg (SD = 4.4) to 22.1 mm Hg immediately after drainage. One third of patients experienced a decrease in the intracranial pressure below 20 mm Hg; in two patients the intracranial pressure dropped less than 1 mm Hg. The following factors predicted 61.5% of the variance in the responsiveness of intracranial pressure to drainage: vecuronium hypothermia, baseline cerebral perfusion pressure and acuity of illness. Cerebrospinal fluid drainage provides a transient decrease in intracranial pressure without a measurable improvement in other indices of cerebral perfusion.

Hemodynamic effect of mannitol in a canine model of concomitant increased intracranial pressure and hemorrhagic shock

The use of mannitol in the management of head injury has been considered a threat to hemodynamic stability in hypotensive multiply injured patients. To evaluate this contention, we compared mannitol with normal saline administration in a canine model combining elevated intracranial pressure (ICP) and hemorrhagic shock. Mongrel dogs were bled to and maintained at a mean arterial pressure (MAP) of 60 mm Hg for 30 minutes. Following this, ICP was elevated to and sustained at 25 mm Hg for 45 minutes by inflating an epidural balloon. The dogs were then randomized to resuscitation with 2 g/kg of mannitol in saline (total volume, 20 mL/kg; n = 5) or 20 mL/kg of normal saline alone (n = 5). All dogs were successfully resuscitated, and MAP returned to baseline levels in both groups. ICP was significantly lower and urine output significantly higher in the mannitol group than in saline controls (P less than .01). Moreover, cerebral perfusion pressure, cardiac index, and left ventricular stroke work index were significantly improved in dogs given mannitol versus controls during the first hour of resuscitation (P less than .05). Mannitol ameliorates increases in ICP without compromising hemodynamic resuscitation in a canine model of concomitant increased ICP and shock.

Intracranial hypertension and brain oedema in albino rabbits. Part I: Experimental models

Three models of experimental cerebral oedema in rabbits are described, one producing vasogenic oedema with a cold lesion, the other producing a cytotoxic cerebral oedema with a metabolic inhibitor, 6-aminonicotinamide (6-ANA), and finally a model employing in the same animal both vasogenic and cytotoxic injuries. The following parameters were assessed: behaviour, EEG, intracranial pressure (ICP), cerebral elastance (Em), blood brain barrier integrity, brain water, electrolyte content, and volume change. Behaviour was normal in the cold lesion group, was abnormal following the administration of 6-ANA, and pronouncedly abnormal in animals with a combined lesion. Mean ICP (PaCO2 37 +/- 42 torr) in the control group was 2.7 +/- 2 torr, in the cold lesion group 8.4 +/-6, in the 6-ANA group it was 8.7 +/- 4, and in the combined lesion group 15.8 +/- 8 torr. Em for the control group was 2.6 +/- 1.3 torr, in the cold lesion group it was 5.6 +/- 4 torr, in the 6-ANA group it was 8.8 +/- 5 torr, and in the combined lesion group it was 8.0 +/- 4 torr. The 6-ANA group manifested oedema that involved primarily the grey matter. In the control animals grey matter water content was 79.99 +/- 0.8%, and in the 6-ANA group it was 81.73 +/- 0.9% (P less than 0.001). A group had both grey and white matter content measurements under the area of a sham lesion, and this was 79.2 +/- 1.3% for the left hemisphere and 79.1 +/- 1.3% for the right. Following a cold lesion of the left hemisphere, the water content was 81.85 +/- 1% (P less than 0.005), and 80.25 +/- 1% (P less than 0.01) in the unlesioned right hemisphere. In those animals with combined cold lesion and 6-ANA administration, the water content of the left hemisphere increased to 82.8 +/- 1% (P less than 0.05 from vasogenic oedema alone), and in the right hemisphere to 81.1 +/- 1% (P less than 0.5 from vasogenic oedema alone).

Upright patient positioning in the management of intracranial hypertension

Utilizing either a subarachnoid screw or an intraventricular cannula, intracranial pressure was continuously monitored in 24 patients with established or potential neurological impairment of various etiologies. Marked diminution in intracranial pressure was observed in the sitting or semisitting position in the 13 patients with documented intracranial hypertension as well as in the 11 in whom intracranial pressure was not elevated. This sustained effect was noted even when superimposed on intensive medical management of intracranial hypertension.

Methodology for the control of intracranial pressure with hypertonic mannitol

The response to intravenous bolus administrations and continuous infusions of hypertonic mannitol to control elevated (greater than 25 torr) intracranial pressure (ICP) is presented. Sixty patients received 120 bolus infusions of mannitol (0.18-2.5 g/kg/dose) with a prompt peak reduction at 44 minutes (range 18 to 120 minutes). There was no relationship between dosage and rapidity of peak response. All administrations of 1.0g/kg/dose, or higher, consistently reduced ICP 10% or more from control values, but dosages below 1 gm/kg/dose did not always reduce ICP. Return to control ICP following mannitol was unpredictable, and was related to the initial ICP and the volume of fluid replacement. A continuous infusion of mannitol was administered to maintain ICP below 25 torr in 18 patients. This infusion ranged from 6 to 100 hours (X 28.8+/-28.9 hours) and required a total dosage of 2-20 mg/kg, and was successful in 16 of the 18 patients. Emphasis is placed on close observation of the patient's serum osmolality and electrolytes during therapy, as well as quality and magnitude of replacement. No set rules are given for control of ICP, but a guideline is made to meet the individual patient's requirements.

The effect of high dose dexamethasone in children with severe closed head injury. A preliminary report

Out of a total 157 hospitalized head-injured children, twelve years of age and under, fifteen were considered to be severe, three of whom died within 72 hours of admission. Nine children with closed head injuries who were in coma for at least 24 hours (did not open eyes, speak, or follow commands), with absent or impaired oculocephalic reflex, impaired pupil reactivity to light, and who were decerebrating for at least twelve hours, were studied. Five were given high dose dexamethasone therapy (1 mg/kg) within six hours of injury, repeated at six hours, and then maintained at 1 mg/kg/day for eight days, and four either received none or were treated with a low dose regimen (0.25 mg/kg/day). In those receiving high dose therapy, intracranial pressure waves were noticeably less, peak intracranial pressure was lower, and intensive care and hospital stay were shorter. It was also noted that in the high dose therapy group spontaneous eye opening and speech returned sooner, and all were considered to have returned to their premorbid status by six months following injury. Of the no steroid or low dose group, one died, and of the remainder at six months one was aphasic and still decerebrating, another was aphasic and severely handicapped, and the third returned to school seven months after injury.

The physiopathology of respiration in neurosurgical patients

✓ Regulation of respiration is summarized as to peripheral and central chemoreceptors, controllers of voluntary and automatic respiration, and stimulators (CO2, O2, and pH). The information that may be obtained from blood-gas analysis is reviewed and basic problems in acid-base imbalance described. Commonly employed respiratory patterns are discussed.

Preoperative pulmonary assessment necessary in elective intracranial situations, spinal cord injuries, and pediatric neurosurgery is outlined. Some of the special problems of the patient with multiple trauma, including injury to the central nervous system are reviewed. Central and peripheral factors that cause respiratory difficulty in head-injured patients are tabulated, and an outline is given of diagnosis and therapy. There are many possible causes of intraoperative hypoxia and hypercarbia, and these complications with their prevention or treatment are examined. Criteria for extubation are established. Finally, postoperative pulmonary care in elective, emergency, and cord injury situations is discussed. The key to successful perioperative pulmonary care of the neurosurgical patient requires close cooperation between the neurosurgeon and anesthesiologist.

Effects of steroids on behavior, electrophysiology, water content and intracranial pressure in cerebral cytotoxic edema

The effect of therapy with methylprednisolone sodium succinate (5.33 mg/kg/day) and dexamethasone sodium phosphate (1 mg/kg/day) on grey matter of rabbits rendered edematous by a metabolic blocker, 6-aminonicotinamide, is presented. Methylprednisolone was observed to significantly reduce the water content of the grey matter (p less than 0.001), whereas dexamethasone had little effect. Both agents, however, were equally effective in reducing intracranial pressure (p less than 0.001) and improving intracranial elastance, when compared to untreated animals. However, in the dexamethasone-treated group, there was improved behavior and EEG findings in 50% of the animals when compared to the untreated controls, and similar improvement was present in less than 15% of the methylprednisolone group. The disparity between the effects on water content, behavior and EEG supports the thesis that in cerebral edema these agents have a metabolic effect out of proportion to their effect on tissue water.

Problems in brain death determination

During the last decade there has been philosophical acceptance of the concept that the state of brain death is equivalent to total patient death. The application of this concept to clinical medicine has been associated with major problems in both the diagnosis of brain death and the medical management of the brain dead patient. In our experience with 176 consecutive cases of suspected brain death over a seven-year period, we have found that a standardized protocol applied by experienced clinicians will minimize these problems.