Individualizing Thresholds of Cerebral Perfusion Pressure Using Estimated Limits of Autoregulation. (Patel)

Donnelly J, et al. Individualizing Thresholds of Cerebral Perfusion Pressure Using Estimated Limits of Autoregulation. Crit Care Med. 2017 Sep;45(9):1464-1471.

OBJECTIVES: In severe traumatic brain injury, cerebral perfusion pressure management based on cerebrovascular pressure reactivity index has the potential to provide a personalized treatment target to improve patient outcomes. So far, the methods have focused on identifying “one” autoregulation-guided cerebral perfusion pressure target-called “cerebral perfusion pressure optimal”. We investigated whether a cerebral perfusion pressure autoregulation range-which uses a continuous estimation of the “lower” and “upper” cerebral perfusion pressure limits of cerebrovascular pressure autoregulation (assessed with pressure reactivity index)-has prognostic value.

DESIGN: Single-center retrospective analysis of prospectively collected data.

SETTING: The neurocritical care unit at a tertiary academic medical center.

PATIENTS: Data from 729 severe traumatic brain injury patients admitted between 1996 and 2016 were used. Treatment was guided by controlling intracranial pressure and cerebral perfusion pressure according to a local protocol.

INTERVENTIONS: None.

METHODS AND MAIN RESULTS: Cerebral perfusion pressure-pressure reactivity index curves were fitted automatically using a previously published curve-fitting heuristic from the relationship between pressure reactivity index and cerebral perfusion pressure. The cerebral perfusion pressure values at which this “U-shaped curve” crossed the fixed threshold from intact to impaired pressure reactivity (pressure reactivity index = 0.3) were denoted automatically the “lower” and “upper” cerebral perfusion pressure limits of reactivity, respectively. The percentage of time with cerebral perfusion pressure below (%cerebral perfusion pressure < lower limit of reactivity), above (%cerebral perfusion pressure > upper limit of reactivity), or within these reactivity limits (%cerebral perfusion pressure within limits of reactivity) was calculated for each patient and compared across dichotomized Glasgow Outcome Scores. After adjusting for age, initial Glasgow Coma Scale, and mean intracranial pressure, percentage of time with cerebral perfusion pressure less than lower limit of reactivity was associated with unfavorable outcome (odds ratio %cerebral perfusion pressure < lower limit of reactivity, 1.04; 95% CI, 1.02-1.06; p < 0.001) and mortality (odds ratio, 1.06; 95% CI, 1.04-1.08; p < 0.001).

CONCLUSIONS: Individualized autoregulation-guided cerebral perfusion pressure management may be a plausible alternative to fixed cerebral perfusion pressure threshold management in severe traumatic brain injury patients. Prospective randomized research will help define which autoregulation-guided method is beneficial, safe, and most practical.

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Early Systolic Dysfunction Following Traumatic Brain Injury: A Cohort Study. (Stulce)

Krishnamoorthy V, Rowhani-Rahbar A, Gibbons EF, et al. Early Systolic Dysfunction Following Traumatic Brain Injury: A Cohort Study. Crit Care Med. 2017 Apr 10. [Epub ahead of print]

OBJECTIVE: Prior studies have suggested that traumatic brain injury may affect cardiac function. Our study aims were to determine the frequency, longitudinal course, and admission risk factors for systolic dysfunction in patients with moderate-severe traumatic brain injury.

DESIGN: Prospective cohort study.

SETTING: Level 1 trauma center.

MEASUREMENTS: Transthoracic echocardiogram within 1 day and over the first week after moderate-severe traumatic brain injury; transthoracic echocardiogram within 1 day after mild traumatic brain injury (comparison group).

MEASUREMENTS AND MAIN RESULTS: Systolic function was assessed by transthoracic echocardiogram, and systolic dysfunction was defined as fractional shortening less than 25%. Multivariable Poisson regression models examined admission risk factors for systolic dysfunction. Systolic function in 32 patients with isolated moderate-severe traumatic brain injury and 32 patients with isolated mild traumatic brain injury (comparison group) was assessed with transthoracic echocardiogram. Seven (22%) moderate-severe traumatic brain injury and 0 (0%) mild traumatic brain injury patients had systolic dysfunction within the first day after injury (p < 0.01). All patients with early systolic dysfunction recovered in 1 week. Younger age (relative risk, 0.87; 95% CI, 0.79-0.94; for 1 yr increase in age) and lower admission Glasgow Coma Scale score (relative risk, 0.34; 95% CI, 0.20-0.58; for one unit increase in Glasgow Coma Scale) were independently associated with the development of systolic dysfunction among moderate-severe traumatic brain injury patients.

CONCLUSIONS: Early systolic dysfunction can occur in previously healthy patients with moderate-severe traumatic brain injury, and it is reversible over the first week of hospitalization. Younger age and lower admission Glasgow Coma Scale score are independently associated with the development of systolic dysfunction after moderate-severe traumatic brain injury.

Functional Status Scale in Children With Traumatic Brain Injury: A Prospective Cohort Study. (Dodd)

Bennett TD, et al. Functional Status Scale in Children With Traumatic Brain Injury: A Prospective Cohort Study. Pediatr Crit Care Med. 2016
Dec;17(12):1147-1156.

OBJECTIVES: In children with traumatic brain injury, 1) to describe the hospital discharge functional outcome and change from baseline function using the Functional Status Scale and 2) to determine any associations between discharge Functional Status Scale and age, injury mechanism, neurologic examination, imaging, and other predictors of outcome.

DESIGN: Prospective observational cohort study, May 2013 to November 2015.

SETTING: Two U.S. children’s hospitals designated as American College of Surgeons level 1 pediatric trauma centers.

PATIENTS: Children less than 18 years old admitted to an ICU with acute traumatic brain injury and either a surgical or critical care intervention within the first 24 hours or in-hospital mortality.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: The primary outcome was hospital discharge Functional Status Scale. Most, 133 of 196 (68%), had severe traumatic brain injury (admission Glasgow Coma Scale, 3-8). Overall hospital mortality was 14%; 20% among those with severe traumatic brain injury. Hospital discharge FunctionalStatus Scale had an inverse relationship with Glasgow Coma Scale: for each increase in admission Glasgow Coma Scale by 1, the discharge Functional Status Scale decreased by 0.5 (95% CI, 0.7-0.3). Baseline Functional Status Scale was collected at one site (n = 75). At that site, nearly all (61/62) of the survivors had normal or near-normal (≤ 7) preinjury Functional Status Scale. More than one-third, 23 of 62 (37%), of survivors had new morbidity at hospital discharge (increase in Functional Status Scale, ≥ 3). Among children with severe traumatic brain injury who had baseline Functional Status Scale collected, 21 of 41 survivors (51%) had new morbidity at hospital discharge. The mean change in Functional Status Scale from baseline to hospital discharge was 3.9 ± 4.9 overall and 5.2 ± 5.4 in children with severe traumatic brain injury.

CONCLUSIONS: More than one-third of survivors, and approximately half of survivors with severe traumatic brain injury, will have new morbidity. Hospital discharge Functional Status Scale, change from baseline Functional Status Scale, and new morbidity acquisition can be used as outcome measures for hospital-based care process improvement initiatives and interventional studies of children with traumatic brain injury.

Intracranial Pressure Monitoring in Infants and Young Children With Traumatic Brain Injury. (Carroll)

Dixon RR, et al. Intracranial Pressure Monitoring in Infants and Young Children With Traumatic Brain Injury. Pediatr Crit Care Med. 2016 Nov; 17(11):1064-1072.

OBJECTIVE: To examine the use of intracranial pressure monitors and treatment for elevated intracranial pressure in children 24 months old or younger with traumatic brain injury in North Carolina between April 2009 and March 2012 and compare this with a similar cohort recruited 2000-2001.

DESIGN: Prospective, observational cohort study.

SETTING: Twelve PICUs in North Carolina.

PATIENTS: All children 24 months old or younger with traumatic brain injury, admitted to an included PICU.

INTERVENTIONS: None.

MEASUREMENT AND MAIN RESULTS: The use of intracranial pressure monitors and treatments for elevated intracranial pressure were evaluated in 238 children with traumatic brain injury. Intracranial pressure monitoring (risk ratio, 3.7; 95% CI, 1.5-9.3) and intracranial pressure therapies were more common in children with Glasgow Coma Scale less than or equal to 8 compared with Glasgow Coma Scale greater than 8. However, only 17% of children with Glasgow Coma Scale less than or equal to 8 received a monitoring device. Treatments for elevated intracranial pressure were more common in children with monitors; yet, some children without monitors received therapies traditionally used to lower intracranial pressure. Unadjusted predictors of monitoring were Glasgow Coma Scale less than or equal to 8, receipt of cardiopulmonary resuscitation, nonwhite race. Logistic regression showed no strong predictors of intracranial pressure monitor use. Compared with the 2000 cohort, children in the 2010 cohort with Glasgow Coma Scale less than or equal to 8 were less likely to receive monitoring (risk ratio, 0.5; 95% CI, 0.3-1.0), although the estimate was not precise, or intracranial pressure management therapies.

CONCLUSION: Children in the 2010 cohort with a Glasgow Coma Scale less than or equal to 8 were less likely to receive an intracranial pressure monitor or hyperosmolar therapy than children in the 2000 cohort; however, about 10% of children without monitors received therapies to decrease intracranial pressure. This suggests treatment heterogeneity in children 24 months old or younger with traumatic brain injury and a need for better evidence to support treatment recommendations for this group of children.