Steroid administration and nitrogen excretion in the head-injured patient

Evaluation of Electrolyte Imbalance in Patients With Traumatic Brain Injury Admitted in the Central ICU of a Tertiary Care Centre: A Prospective Observational Study

Introduction Electrolyte imbalance is a salient finding in traumatic brain injury which can derail their clinical course of recovery in physical and cognitive health while prolonging the hospital stay. Objective This study aims to understand the variation in electrolyte profile that occurs in traumatic brain injury patients which can help in better patient management. Materials and method 50 trauma patients with head injury (Group A) and 50 patients without head injury (Group B) admitted in Central ICU (CICU) under the Department of Anaesthesiology, Assam Medical College and Hospital (AMCH) were selected and analysed with regard to their electrolyte variability. Result All trauma patients with head injury developed an imbalance to one or more electrolytes. Then mean electrolyte level in trauma patients with a head injury and in trauma patients without head injury were 139.3±7.45 vs 143.65±8.89, p<0.05 (sodium), 3.49±0.44 vs 3.88±0.49, p<0.05 (potassium), 7.81±0.5 vs 8.9± 0.35, p<0.05 (calcium) and 2±0.33 vs 2.47±0.41, p<0.05 (magnesium) respectively. Also, patients in the head injury group had a higher incidence of hypoalbuminemia than patients without head injury 2.47±0.67 vs 2.83±0.74 (p<0.05). Conclusion We conclude that traumatic brain injury patients have a greater risk of electrolyte imbalance, viz. hyponatremia, hypokalaemia, hypocalcaemia as well as hypomagnesemia, and hypophosphatemia along with hypoalbuminemia.

Steroids and Survival in Critically Ill Adult Patients: A Meta-analysis of 135 Randomized Trials

OBJECTIVE

Corticosteroids have important effects on intermediate outcomes in critically ill patients, but their effect on survival is unknown. The objective of this meta-analysis was to analyze the effect on mortality of corticosteroids in critical and perioperative settings.

DESIGN

A meta-analysis of randomized trials.

SETTING

PubMed, Embase, BioMed Central, Google Scholar, and the Cochrane Central Register of Controlled Trials were searched to February 1, 2018, for randomized trials comparing corticosteroids with placebo or standard care.

PARTICIPANTS

Critically ill or surgical adult patients.

INTERVENTIONS

Corticosteroids compared with placebo or standard care.

MEASUREMENTS AND MAIN RESULTS

A total of 44,553 patients from 135 studies were included. Overall, mortality in the corticosteroid group and in the control group were similar (16% v 16%; p = 0.9). Subanalyses identified a beneficial effect of corticosteroids on survival in patients with respiratory system diseases (9% v 13%; p < 0.001) and bacterial meningitis (28% v 32%; p= 0.04), and a detrimental effect on survival in patients with traumatic brain injury (22% v 19%; p < 0.001). No differences in mortality were found in patients with cardiac diseases (7% v 6%; p = 0.7), in patients undergoing cardiac surgery (2.8% v 3.2% p = 0.14), and when treatment duration or patient age were considered.

CONCLUSIONS

This meta-analysis documents the safety of corticosteroids in the overall critically ill population with the notable exception of brain injury patients, a setting where the authors confirmed their detrimental effect on survival. A possible beneficial effect of corticosteroids on survival was found among patients with respiratory diseases and in patients with bacterial meningitis.

Energy expenditure in children after severe traumatic brain injury

OBJECTIVE

To evaluate energy expenditure in a cohort of children with severe traumatic brain injury.

DESIGN

A prospective observational study.

SETTING

A pediatric neurotrauma center within a tertiary care institution.

PATIENTS

Mechanically ventilated children admitted with severe traumatic brain injury (Glasgow Coma Scale < 9) with a weight more than 10 kg were eligible for study. A subset of children was co-enrolled in a phase 3 study of early therapeutic hypothermia. All children were treated with a comprehensive neurotrauma protocol that included sedation, neuromuscular blockade, temperature control, antiseizure prophylaxis, and a tiered-based system for treating intracranial hypertension.

INTERVENTIONS

Within the first week after injury, indirect calorimetry measurements were performed daily when the patient's condition permitted.

MEASUREMENTS AND MAIN RESULTS

Data from 13 children were analyzed (with a total of 32 assessments). Measured energy expenditure obtained from indirect calorimetry was compared with predicted resting energy expenditure calculated from Harris-Benedict equation. Overall, measured energy expenditure/predicted resting energy expenditure averaged 70.2% ± 3.8%. Seven measurements obtained while children were hypothermic did not differ from normothermic values (75% ± 4.5% vs 68.9% ± 4.7%, respectively, p = 0.273). Furthermore, children with favorable neurologic outcome at 6 months did not differ from children with unfavorable outcome (76.4% ± 6% vs 64.7% ± 4.7% for the unfavorable outcome, p = 0.13).

CONCLUSIONS

Contrary to previous work from several decades ago that suggested severe pediatric traumatic brain injury is associated with a hypermetabolic response (measured energy expenditure/predicted resting energy expenditure > 110%), our data suggest that contemporary neurocritical care practices may blunt such a response. Understanding the metabolic requirements of children with severe traumatic brain injury is the first step in development of rational nutritional support goals that might lead to improvements in outcome.

Early enteral nutrition and clinical outcomes of severe traumatic brain injury patients in acute stage: a multi-center cohort study

Guidelines for patients with severe traumatic brain injury (sTBI) published in 2007 recommend providing early nutrition after trauma. Early enteral nutrition (EN) started within 48 h post-injury reduces clinical malnutrition, prevents bacterial translocation from the gastrointestinal tract, and improves outcome in sTBI patients sustaining hypermetabolism and hypercatabolism. The aim of this study was to examine the effect of early EN support on survival rate, Glasgow Coma Scale (GCS) score, and clinical outcome of sTBI patients. Medical records of sTBI patients with GCS scores 4-8 were recruited from 18 hospitals in Taiwan, excluding patients with GCS scores ≤3. During 2002-2010, data from 145 EN patients receiving appropriate calories and nutrients within 48 h post-trauma were collected and compared with 152 non-EN controls matched for gender, age, body weight, initial GCS score, and operative status. The EN patients had a greater survival rate and GCS score on the 7th day in the intensive care unit (ICU), and a better outcome at 1 month post-injury. After adjusting for age, gender, initial GCS score, and recruitment period, the non-EN patients had a hazard ratio of 14.63 (95% CI 8.58-24.91) compared with EN patients. The GCS score during the first 7 ICU days was significantly improved among EN patients with GCS scores of 6-8 compared with EN patients with GCS scores of 4-5 and non-EN patients with GCS scores of 6-8. This finding demonstrates that EN within 48 h post-injury is associated with better survival, GCS recovery, and outcome among sTBI patients, particularly in those with a GCS score of 6-8.

Metabolism and nutrition in patients with moderate and severe traumatic brain injury: A systematic review

PRIMARY OBJECTIVE

To examine the evidence on the metabolic state and nutritional treatment of patients with moderate-to-severe traumatic brain injury (TBI).

RESEARCH DESIGN

A systematic review of the literature.

METHODS AND PROCEDURES

From 1547 citations, 232 articles were identified and retrieved for text screening. Thirty-six studies fulfilled the criteria and 30 were accepted for data extraction.

MAIN OUTCOMES AND RESULTS

Variations in measurement methods and definitions of metabolic abnormalities hampered comparison of studies. However, consistent data demonstrated increased metabolic rate (96-160% of the predicted values), of hypercatabolism (-3 to -16 g N per day) and of upper gastrointestinal intolerance in the majority of the patients during the first 2 weeks after injury. Data also indicated a tendency towards less morbidity and mortality in early fed patients.

CONCLUSIONS

The impact of timing, content and ways of administration of nutritional support on neurological outcome after TBI remains to be demonstrated.

Corticosteroids for acute traumatic brain injury

BACKGROUND

Traumatic brain injury is a leading cause of death and disability. Corticosteroids have been widely used in treating people with traumatic brain injury.

OBJECTIVES

To quantify the effectiveness and safety of corticosteroids in the treatment of acute traumatic brain injury.

SEARCH STRATEGY

Electronic sources: MEDLINE, EMBASE, Cochrane Library and specialised database searches. Additional hand searching and contact with trialists. Date of the most recent search October 2004.

SELECTION CRITERIA

All randomised controlled trials of corticosteroid use in acute traumatic brain injury with adequate or unclear allocation concealment.

DATA COLLECTION AND ANALYSIS

Quality of allocation concealment was scored. Data on numbers of participants randomised, numbers lost to follow up, length of follow up, case fatality rates, disablement, infections and gastrointestinal bleeds were extracted independently and checked.

MAIN RESULTS

We identified 20 trials with 12303 randomised participants. The effect of corticosteroids on the risk of death was reported in 17 included trials. Due to significant heterogeneity we did not calculate a pooled estimate of the risk of death. The largest trial, with about 80% of all randomised participants, found a significant increase in the risk ratio of death with steroids 1.18 (1.09 to 1.27). For the nine trials that reported death or severe disability, the pooled relative risk was 1.01 (0.91 to 1.11), although this does not yet contain data from the largest trial. For infections the pooled risk ratio from five trials was 1.03 (0.99 to 1.07) and for the ten trials reporting gastrointestinal bleeding 1.23 (0.91 to 1.67).

AUTHORS' CONCLUSIONS

In the absence of a meta-analysis, we feel most weight should be placed on the result of the largest trial. The increase in mortality with steroids in this trial suggest that steroids should no longer be routinely used in people with traumatic head injury.

Hyperglycemia in dogs and cats with head trauma: 122 cases (1997-1999)

OBJECTIVE

To determine whether hyperglycemia is associated with head trauma in dogs and cats and whether the degree of hyperglycemia corresponds to severity of neurologic injury or outcome.

DESIGN

Retrospective study.

ANIMALS

52 dogs and 70 cats with head trauma and 122 age- and species-matched control dogs and cats.

PROCEDURE

Severity of head trauma was classified as mild, moderate, or severe. Blood glucose concentrations recorded within 1 hour after admission were compared between case and control animals and among groups when case animals were grouped on the basis of severity of head trauma or outcome.

RESULTS

Blood glucose concentration was significantly associated with severity of head trauma in dogs and cats and was significantly higher in dogs and cats with head trauma than in the control animals. However, blood glucose concentration was not associated with outcome.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that dogs and cats with head trauma may have hyperglycemia and that degree of hyperglycemia was associated with severity of head trauma. However, degree of hyperglycemia was not associated with outcome for dogs and cats with head trauma. Because hyperglycemia can potentiate neurologic injury, iatrogenic hyperglycemia should be avoided in patients with head trauma.

The Brain Trauma Foundation. The American Association of Neurological Surgeons. The Joint Section on Neurotrauma and Critical Care. Nutrition

Data show that starved head-injured patients lose sufficient nitrogen to reduce weight by 15% per week. Class II data show that 100-140% replacement of resting metabolism expenditure with 15-20% nitrogen calories reduces nitrogen loss. Data in non-head injured patients show that a 30% weight loss increased mortality rate. Class I data suggests that nonfeeding of head-injured patients by the first week increases mortality rate. The data strongly support feeding at least by the end of the first week. It has not been established that any method of feeding is better than another or that early feeding prior to 7 days improves outcome. Based on the level of nitrogen wasting documented in head-injured patients and the nitrogen sparing effect of feeding, it is a guideline that full nutritional replacement be instituted by day 7.

Corticosteroids for acute traumatic brain injury

BACKGROUND

Traumatic brain injury is a leading cause of death and disability. Corticosteroids have been widely used in treating people with traumatic brain injury.

OBJECTIVES

To quantify the effectiveness and safety of corticosteroids in the treatment of acute traumatic brain injury.

SEARCH STRATEGY

Electronic sources: MEDLINE, EMBASE, Cochrane Library and specialised database searches. Additional hand searching and contact with trialists. Date of the most recent search June 1999.

SELECTION CRITERIA

All randomized controlled trials of corticosteroid use in acute traumatic brain injury with adequate or unclear allocation concealment.

DATA COLLECTION AND ANALYSIS

Quality of allocation concealment was scored. Data on numbers of participants randomized, numbers lost to follow up, length of follow up, case fatality rates, disablement, infections and gastrointestinal bleeds were extracted independently and checked.

MAIN RESULTS

We identified 19 trials with 2295 randomized participants. The effect of corticosteroids on the risk of death was reported in 16 included trials. The pooled relative risk for the 16 trials was 0.96 (95% confidence interval 0.85 to 1. 08). Pooled risk difference was 1.3% (5.2% to 2.5% more). For the nine trials that reported death or severe disability, the pooled relative risk was 1.01 (0.91 to 1.11). For infections the pooled relative risk was 0.94 (0.76 to 1.16) and for the nine trials reporting gastrointestinal bleeding 1.11 (0.54 to 2.26). Using only those trials with the best quality of allocation concealment, the pooled relative risk estimate for death became closer to unity.

REVIEWER'S CONCLUSIONS

Neither moderate benefits nor moderate harmful effects of steroids can be excluded. The widely practicable nature of the drugs and the importance of the health problem suggest that large simple trials are feasible, and worthwhile, to establish whether there are any benefits from corticosteroids in this situation.

The metabolic response to acute traumatic brain injury and implications for nutritional support

An overview of the metabolic response to acute traumatic brain injury is presented. The consequences of hypermetabolism, hypercatabolism, and an altered immune function are discussed. Once a person with acute traumatic brain injury develops this hyperdynamic state, the resultant excessive protein breakdown ensues. This can lead to malnutrition. The feeding methods used to prevent malnutrition are discussed, along with the proper alimentation to provide to diminish the hyperdynamic state and improve immune function.

Survey of intensive care of severely head injured patients in the United Kingdom

OBJECTIVES

To study practice in intensive care of patients with severe head injury in neurosurgical referral centres in United Kingdom.

DESIGN

Structured telephone interview of senior nursing staff in intensive care unit of adult neurosurgical referral centre.

SETTING

39 intensive care units in hospitals that accepted acute head injuries for specialist neurosurgical management, identified from Medical Directory and information from professional bodies.

MAIN OUTCOME MEASURES

Details of organisation and administration of intensive care and patterns of monitoring and treatment for patients admitted with severe head injury.

RESULTS

Patients were managed in specialist neurosurgical intensive care units in 21 of the centres and in general intensive care units in 18. Their intensive care was coordinated by an anaesthetist in 25 units and by a neurosurgeon in 12. Annual case-load varied between units: 20 received > 100 patients, 12 received 50-100, and seven received 25-49. Monitoring and treatment varied considerably between centres. Invasive arterial pressure monitoring was used routinely in 36 units, but central venous pressure monitoring was routinely used in 24 and intracranial pressure was routinely monitored in only 19. Corticosteroids were used to treat intracranial hypertension in 19 units. Seventeen units routinely aimed for arterial carbon dioxide pressure of 3.3-4.0 kPa, and one unit still used severe hyperventilation to a pressure of < 3.3 kPa.

CONCLUSION

The intensive care of patients with acute head injuries varied widely between the centres surveyed. Rationalisation of the intensive care of severe head injury with the production of widely accepted guidelines ought to improve the quality of care.

Survey of critical care management of comatose, head-injured patients in the United States

OBJECTIVE

This survey was designed to study current practices in the monitoring and treatment of patients with severe head injury in the United States.

DATA SOURCES

The collected data represent answers to telephone interviews of nurse managers, clinical specialists, and staff nurses specializing in neurotrauma care at 277 randomly selected hospitals from a total pool of 624 trauma centers. Overall, 261 (94%) centers participated in the survey. Of the participating centers, 219 (84%) were providers of care for severely head-injured patients. In order to assess reliability and account for differences among respondents, personnel from 40 (15%) centers were resurveyed 6 months later and a different nursing professional was interviewed, although the questions remained the same.

DATA EXTRACTION

The largest group of respondents came from level I centers (49%), followed by level II (32%) and level III (2%). Thirty-four percent of the surveyed hospitals had a designated neurologic/neurosurgical intensive care unit, and 24% of all units surveyed were under the direction of either a neurosurgeon or a neurologist. Twenty-eight percent of the centers routinely performed intracranial pressure monitoring, while 7% of the centers reported never using this technique. The use of ventriculostomy catheters for intracranial pressure monitoring was employed in 72% of the centers, but cerebrospinal fluid drainage was utilized by only 44% of the hospitals. The percentage of patients who had their intracranial pressure monitored was significantly higher in level I trauma centers and at hospitals that treated larger numbers of severely head-injured patients (15 to 30 patients per month, which represented 15% of the hospitals surveyed). Hyperventilation and osmotic diuretics were used in 83% of centers to reduce intracranial hypertension. The administration of barbiturates was reported in 33% of the units as a treatment for intracranial hypertension. Corticosteroids were used more than half of the time in 64% of trauma centers. Twenty-nine percent of the centers reported aiming for PaCO2 values of < 25 torr (< 3.3 kPa).

CONCLUSIONS

The survey data indicate that there is a considerable variation in the management of patients with severe head injury in the United States. The establishment of guidelines for the management of head injury based on available scientific data and moderated by practical and financial considerations may lead to improvement in the standard of care.

Metabolic rate in severe head trauma

BACKGROUND

The metabolic rate of patients suffering severe head trauma (HT) is not well defined, and large variations of resting energy expenditure (REE) have been reported, suggesting an important nonuniformity of REE distribution in HT patients. The purpose of this clinical study was to assess the metabolic rate in mechanically ventilated patients suffering from severe isolated HT, or HT associated with other injuries, in the absence of gross motor activity.

METHODS

Eighty HT patients undergoing mechanical ventilation were studied between 48 and 72 hours after injury. Three groups of patients were studied in the following clinical settings: (group A) isolated HT, not receiving morphine (n = 34); (group B) isolated HT, receiving an intravenous perfusion of morphine (n = 26) to control gross motor activity; and (group C) HT associated with other serious injuries, receiving intravenous morphine (n = 20) to induce sedation and analgesia. REE was measured with the open-Douglas-bag method.

RESULTS

No significant differences among the three groups were found in the metabolic rate expressed as the percentage of measured REE from predicted REE and REE expressed in terms of body weight. The mean percent measured REE was 123 +/- 16, and REE expressed in terms of body weight was 30 +/- 5 kcal/kg per day. Severe hypermetabolism was diagnosed if mean percent measured REE was greater than 130 and was present in 25 of 80 (31%) patients.

CONCLUSIONS

Severe HT treated with or without morphine was characterized by a moderate state of hypermetabolism after the first days of trauma, but an important proportion of HT patients showed considerably elevated metabolic rates.

Substrate oxidation and the contribution of protein oxidation to energy expenditure after severe head injury

The 'flow' phase response to head injury is characterized by hypermetabolism and catabolism of lean body mass. In order to measure the contribution of protein oxidation (CPO) to resting metabolic expenditure (RME), 11 severely head injured patients (AIS 5) were studied. All patients had 24 h urine collections for at least 10 days after injury and RME was determined at intervals by indirect calorimetry. No patient received exogenous steroids. Peak urinary nitrogen excretion was 11.63 +/- 1.28 g/m2/day occurring between days 6 and 9 after injury. Fat oxidation was the greatest component of the RME at all times after head injury and the CPO to RME was 26.4 +/- 2.9 per cent during days 1-2, 31.8 +/- 3.3 per cent during days 3-5, 28.6 +/- 3.4 per cent during days 6-9 and 23.3 +/- 3.8 per cent during days 10-20 after injury. These figures are higher than those previously reported for burns, musculoskeletal injury or sepsis. The mechanism for the increased CPO is unclear. It may be related to such conditions of management as paralysis and fasting, but more likely it is an idiosyncratic feature of the metabolic response to head injury.

Impaired utilization of exogenous amino acids after surgery for subarachnoid haemorrhage

We studied the metabolic response to acute aneurysm surgery and its modification by parenteral nutrition. Forty-eight patients receiving perioperative corticosteroid treatment were randomly assigned to receive glucose alone (7.2 kcal/day, D5W + C), glucose and a conventional amino acid solution (7.2 kcal/day and 0.15 gN/day, CAA + C) or glucose and branched chain amino acid enriched solution (7.2 kcal/day and 0.14 gN/day, BCAA + C). Twenty patients without corticosteroid treatment received either glucose alone (7.2 kcal/day, D5W) or glucose and a conventional amino acid solution (7.2 kcal/day and 0.14 gN/day, CAA). Poor nitrogen utilization was indicated by strongly negative nitrogen balance in all groups and a failure of the infused amino acids to improve nitrogen balance. (Day 0; D5W + C: -9.3 +/- 3.6 g/day and CAA + C: -8.2 +/- 9.7 g/day vs CAA: -2.6 +/- 4.9 g/day, p less than 0.05, Day 1; D5W + C: -14.9 +/- 9 g/day vs CAA: -7.7 +/- 6.5 g/day, p less than 0.05, MANOVA). We conclude that subarachnoid haemorrhage and its surgical treatment induce a catabolic response and impaired utilization of exogenous nitrogen, further amplified by perioperative corticosteroids, which is in sharp contrast to the response to surgery not involving the central nervous system.

[Energy metabolism and craniocerebral injury]

Severe head injury induces major hormonal, humoral and metabolic changes, characterized by increases in stress hormone secretion, lymphokines production, associated with high lipid and protein catabolism as well as changes in energy expenditure (EE). Numerous factors influence EE in head-injured patients, particularly anthropometric data, body temperature, nutritional support, level of consciousness, muscular tone and activity. Resting EE is usually increased following brain trauma; however, normal or decreased metabolic rates can be observed in curarized patients on mechanical ventilation or in patients receiving high doses of barbiturates.

Catabolic effect of dexamethasone in patients with major head injuries

In the records of our extensive metabolic studies on trauma victims, we found 16 head injured patients who had no other major injuries. Among them, nine had been given dexamethasone for at least 6 days. The other seven had not received any corticosteroids. There was no significant difference in the Glasgow Coma Scales of the treated and untreated groups. Metabolic balance studies were carried out for at least 3 days, including the periods when the treated patients were receiving dexamethasone. Mean nitrogen balance was -0.296 +/- 0.03 g/kg/day for the treated group and -0.182 +/- 0.03 g/kg/day for the untreated group. This difference was significant (p = 0.02, t-test). Our metabolic data are also consistent with those of other published studies, which used other corticosteroids and somewhat different methodologies. Thus, it is clearly established that corticosteroids cause significant degrees of catabolism in head injured patients, beyond what would "normally" be expected in such patients if they did not receive these drugs.

Methylprednisolone treatments alter apomorphine-induced circling in the rat model of 6-hydroxydopamine-induced striatal denervation

Intrastriatal injection of 6-hydroxydopamine causes significant depletion of dopamine which is associated with contralateral apomorphine-induced rotation in rats. Pretreatment with methylprednisolone (MP) causes almost complete elimination of the apomorphine-induced behavioral responses. In addition, there were significant differences between the lateralization effects of the neurotoxin on the levels of striatal dopamine. These results suggest that MP may have ameliorative effects against the motoric behavioral changes associated with the intrastriatal injection of 6-OHDA.

Mechanisms and implications of hypoalbuminemia in head-injured patients

Severely head-injured patients are hypermetabolic/hypercatabolic and exhibit many aspects of the postinjury acute-phase response. These patients have hypoalbuminemia, hypozincemia, hypoferremia, hypercupria, fever, and increased synthesis of acute-phase proteins such as ceruloplasmin and higher C-reactive protein levels. It has been suggested that increased interleukin-1 (IL-1) in the ventricular fluid may be responsible, at least in part, for these metabolic abnormalities. In the present study, serum albumin levels were evaluated throughout an 18-day study period in 62 head-injured patients receiving aggressive nutritional support. Hypoalbuminemia (mean +/- standard error of the mean 3.10 +/- 0.2 gm/dl; normal value 3.5 to 5 gm/dl) was observed upon hospital admission; these albumin levels continued to decrease until 2 weeks postinjury, despite aggressive nutritional support. This hypoalbuminemia may be mediated via altered endothelial permeability properties due to endothelial cell dysfunction caused by cytokines such as IL-1. Transendothelial movement of albumin was assayed using a pulmonary artery endothelial cell culture system. Both a crude macrophage supernatant derived from a murine P388D cell line having IL-1 activity (mIL-1) and human recombinant IL-1 (rIL-1) were tested. The amount of albumin transferred was time- and concentration-dependent, with maximal transfer at 24 hours and 20 U of mIL-1 per 0.5 ml of culture medium. Endothelial permeability changes observed after incubation with mIL-1 were confirmed using rIL-1. Compared to control cultures, 20 U of rIL-1 and 20 U of mIL-1 increased albumin transfer across endothelial monolayers 205% and 459%, respectively. These findings suggest that the mechanism of hypoalbuminemia seen after severe head trauma can be explained in part by IL-1-induced endothelial cell injury, resulting in enhanced endothelial permeability to albumin.

Nutritional support and measured energy expenditure of the child and adolescent with head injury

Energy expenditure, nitrogen excretion, and serum protein levels were studied from the time of hospital admission until 2 weeks after severe head injury in eight adolescents and four children with peak 24-hour Glasgow Coma Scale scores ranging from 3 to 8. The mean measured energy expenditure (MEE) was 1.3 times Harris and Benedict's predicted value for energy expenditure. Seventy percent of the patients achieved caloric balance (MEE X 1.2) by 4 to 14 days after injury, but balance was not consistently maintained. Five of the 12 patients had intermittent diarrhea, and two had increased gastric residuals. In five patients fluid restrictions were imposed due to either the syndrome of inappropriate secretion of antidiuretic hormone, pulmonary complications, or intracranial pressure complications. For the adolescents (aged 11 to 17 years) the mean calorie intake during the 1st week was 752 kcal/day and for the children (aged 2 to 5 years) it was 340 kcal/day. During the 2nd week the mean calorie intake for the adolescents was 1671 kcal/day and for the children was 691 kcal/day. Mean urinary nitrogen excretion was 307 mg/kg/day for the adolescents and 160 mg/kg/day for the children. The calculated mean nitrogen balance for the eight adolescents and the four younger children was -13.6 and -4.1, respectively. Mean albumin levels decreased from 2.9 gm/dl during the 1st week to 2.4 gm/dl during the 2nd week (normal 3.5 to 5.0 gm/dl). Mean total protein level during the 1st week was 5.4 gm/dl and increased to a mean of 6.0 gm/dl during the 2nd week (normal 6.0 to 7.8 gm/dl). Weight loss ranged from 2 to 26 lb during the 2-week period. From these studies it can be concluded that head injury in the child and adolescent induces a metabolic response that includes increased energy expenditure and decreased serum albumin levels similar to those observed for head-injured adults. Mean nitrogen excretion values are less than those in adults with a severe head injury.

The metabolic response to brain injury

Every year several million people sustain brain injury. The development of an optimal metabolic and nutritional support program for brain-injured patients relies on an understanding of the metabolic response and nutritional complications that occur with brain injury. Severely brain injured patients have increased serum and urine levels of norepinephrine, epinephrine, and cortisol. These patients also have increased oxygen consumption and urinary nitrogen excretion. This group has observed hypozincemia, hyperzincuria, increased serum C-reactive protein and copper concentrations, and hypoalbuminemia in nonsteroid-treated severely brain-injured patients. Experimental head injury produces interleukin-1 (IL-1) of brain origin. This cytokine mediates many of the aspects of the acute phase response, including all of the metabolic abnormalities reported by our group. IL-1, when administered intracerebroventricularly to experimental animals, appears to have enhanced biological activity compared to that administered systemically. Interleukin-1 activity has been found in significant amounts in the intraventricular fluid of head-injured patients. We suggest that IL-1 acts in concert with traditional stress hormones such as epinephrine, norepinephrine, and cortisol to produce the profound metabolic disturbances observed in the head-injured patient.

Physiological and metabolic response to isolated closed-head injury. Part 2: Effects of steroids on metabolism. Potentiation of protein wasting and abnormalities of substrate utilization

In order to determine the effects of steroid administration on the metabolic response to isolated closed-head injury, a longitudinal study was performed. Metabolic indices were prospectively evaluated for the first 5 days postinjury in six patients who received steroids and 10 patients who did not. Patients were carefully screened to eliminate those with associated injuries as well as those with abnormalities due to sepsis. Other than steroid administration, a uniform treatment regimen was used in both groups. Metabolic indices measured on postinjury Days 1, 3, and 5 were analyzed. In addition, data were compared to results in large data banks obtained both from overnight-fasted patients (fasted controls) and from polytrauma victims (stressed controls). Both treatment groups were comparable with respect to age, mean Glasgow Coma Scale scores on admission and on Day 5, and initial intracranial pressure. Metabolic data indicated significantly higher levels of nitrogen excretion and somatic protein mobilization in steroid-treated patients than in patients not receiving steroids. In both groups, glucose levels, the lactate/pyruvate ratio, and branched-chain amino acid levels (all metabolic indices that correlate well with level of stress) initially corresponded to values for stressed controls. By Day 5, values for these variables were similar to fasted controls for the group not receiving steroids. In patients receiving steroids, however, the data remained similar to those for stressed controls. It is concluded that steroids prolong the metabolic abnormalities associated with the initial phase of head injury. In view of inconclusive data regarding benefit from steroid administration, serious questions must be raised regarding the use of these catabolic agents in this setting.

Assessment of nutritional requirements of head-injured patients

A nomogram is presented for estimation of energy expenditure at the bedside in comatose patients during the first 2 weeks after brain injury. In analysis of 312 days of energy expenditure in 57 patients, a combination of Glasgow Coma Scale (GCS) score, heart rate (HR), and days since injury (DSI) was found with multiple regression analysis to provide good prediction of resting metabolic expenditure (RME) according to the following relationship: %RME = 152 - 14(GCS score) + 0.4(HR) + 7(DSI) (n = 111, r = 0.7, p less than 0.001). In non-comatose patients, predictive ability was less strong due to inability to measure truly rested values, but HR and GCS score could be used to predict energy expenditure by this relationship: %RME = 90 - 3 (GCS score) + 0.9 (HR) (n = 135, r = 0.47, p less than 0.001). In six patients, paralysis was found to decrease energy expenditure to between 100% and 125% of expected. Movement or stimulation had little effect on energy expenditure in patients who could localize stimuli but increased rested values by 20% in posturing patients. Analysis of fasted balance periods of nitrogen excretion in 22 patients based on 273 days of measurement showed a significant relationship between creatinine-height index (an index of muscle mass) and nitrogen excretion, but no relationship between nitrogen excretion and weight, temperature, and RME. Levels of retention of nitrogen with feeding could not be predicted by any of these variables. Feeding of the individual comatose patient is best guided at present by estimation of energy expenditure using a nomogram and periodic measurement of urinary nitrogen excretion.