The epidemiology of pediatric traumatic brain injury in Minnesota.

OBJECTIVES: To determine the epidemiology of pediatric traumatic brain injury (TBI) in a midwestern state and to examine differences between metropolitan and nonmetropolitan residents. DESIGN: Population-based case series. PARTICIPANTS: Patients aged 0-19 years sustaining TBI in 1993 that resulted in hospitalization or death. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Incidence, mortality and case-fatality rates, length of hospital stay, discharge status, and Glasgow Outcome Scale score. RESULTS: Nine hundred seventy-seven patients met inclusion criteria. Incidence, mortality, and case-fatality rates were 73.5 per 100 000, 9.3 per 100 000, and 12.8 per 100, respectively. Higher median household incomes and percentages of adult high-school graduates in a patient's census block group correlated with lower incidence. Median length of stay was 2 days. Of those included in the study, 720 patients (74%) were discharged home with self-care. Three hundred fifty-seven patients met criteria for severe TBI; 346 (97%) were assigned Glasgow Outcome Scale scores, of which 161 (47%) had disabilities or died. Severe TBI was associated with nonmetropolitan residence, higher median household income, and certain injury mechanisms. Incidence was similar for metropolitan and nonmetropolitan residents. Median head-region Abbreviated Injury Score, Injury Severity Score, and mortality and case-fatality rates were higher for nonmetropolitan residents. CONCLUSIONS: This study reports the lowest incidence of pediatric TBI that results in death or hospitalization to date. One half of severely injured patients suffered poor outcomes. A greater proportion of nonmetropolitan than metropolitan residents suffered severe TBI and had higher mortality and case-fatality rates.

Factors associated with significant injuries in youth ice hockey players.

STUDY OBJECTIVE: To assess the implementation of published injury prevention strategies in injured youth ice hockey players, to examine factors contributing to current youth ice hockey injuries, and to assess attitudes of participants toward injury-risk activities. METHODS: Case series describing a convenience sample of 103 children presenting to a children's hospital emergency department with an injury sustained playing youth ice hockey. Using a questionnaire, patients self-reported their compliance with protective equipment guidelines, the circumstances of injury, and their attitudes toward risk-taking in youth ice hockey. RESULTS: A total of 103 patients suffered 113 injuries. For each piece of required equipment, compliance approached 100%. Penalties were assigned on 4% of plays causing injury. An additional 36% of patients injured during game play felt that a penalty should have been assigned. Fifty-seven percent of injuries were caused by checking. Fifty-eight percent of injuries caused by checking met our criteria for significant injury. Significant injury was more likely when initiating or receiving a check perceived to be legal than when receiving a check perceived as illegal (P = 0.032). Twenty-four percent of patients stated spinal cord injury and 45% stated brain injury was not possible given their usual protective equipment. To win, 32% of patients stated that they would check illegally, and 6% stated that they would purposely injure. CONCLUSION: While compliance with protective equipment requirements was good, rule enforcement was perceived to be inadequate. Elimination of checking would potentially reduce the number of significant injuries more than would the enforcement of existing rules. Injured youth hockey players are underinformed about the hazards of their sport and are too willing to engage in potentially injurious activities.

Outpatient rapid intravenous rehydration to correct dehydration and resolve vomiting in children with acute gastroenteritis.

STUDY OBJECTIVE: To determine the efficacy of outpatient rapid i.v. rehydration in correcting dehydration and resolving vomiting in children with mild to moderate dehydration resulting from acute gastroenteritis. METHODS: We carried out a prospective cohort study in an urban children's hospital. A convenience sample of 58 children aged 6 months to 13 years, with acute gastroenteritis and clinically estimated dehydration of 5% to 10% body weight, was assembled. All patients had been vomiting for less than 48 hours, had vomited at least five times in the 24 hours preceding presentation, and had metabolic acidosis (serum bicarbonate concentration, 18 mEq/L or less). Each patient received an i.v. infusion of 20 to 30 mL/kg isotonic crystalloid solution over 1 to 2 hours, followed by the oral administration of 1 to 3 ounces of clear fluid. Patients who subsequently vomited were admitted for continued i.v. fluid therapy. Patients who tolerated oral fluid were discharged; their caregivers were contacted by telephone 24 to 48 hours after discharge. RESULTS: All patients had improved hydration status after rapid i.v. rehydration. Sixteen patients (28%) did not tolerate oral fluids after rapid i.v. rehydration and were admitted; 11 of these patients had a serum bicarbonate concentration of 13 mEq/L or less. The other 42 patients (72%) tolerated oral fluids after rapid i.v. rehydration and were discharged; 41 of these patients had a serum bicarbonate concentration greater than 13 mEq/L. The frequency of serum bicarbonate concentration of 13 mEq/L or less on presentation was significantly greater (P = .001) in patients requiring hospitalization than in those discharged from the emergency department after rapid i.v. rehydration. Of 40 patients whose caregivers were contacted after discharge, 34 (85%) required no further medical evaluation or treatment for any reason, including inadequate hydration; 29 of these patients vomited no more than once. Six of the discharged patients (15%) required further medical evaluation and were admitted; four had recurrent vomiting and dehydration, two had not vomited but were dehydrated as a result of diarrheal fluid loss or inadequate oral fluid intake. CONCLUSION: Outpatient rapid i.v. rehydration is safe and effective in correcting dehydration and resolving vomiting in selected children with acute gastroenteritis and mild to moderate dehydration. In our study, most children who presented with a serum bicarbonate concentration greater than 13 mEq/L tolerated oral fluids after rapid i.v. rehydration and were further managed as outpatients without complications. By contrast, most children with a serum bicarbonate concentration of 13 mEq/L or less usually did not tolerate oral fluids after rapid i.v. rehydration and required more prolonged i.v. fluid therapy. All discharged patients, regardless of their serum bicarbonate concentration, demonstrated the ability to tolerate orally administered fluid.

Evaluating ethical sensitivity in medical students: using vignettes as an instrument.

As a preliminary step to beginning to assess the usefulness of clinical vignettes to measure ethical sensitivity in undergraduate medical students, five clinical vignettes with seven to nine ethical issues each were created. The ethical issues in the vignettes were discussed and outlined by an expert panel. One randomly selected vignette was presented to first, second and third year students at the University of Toronto as part of another examination. The students were asked to list the issues presented by the patient problem. Responses from 281 students were obtained. These students identified an average of 2.72 ethical issues per vignette. Each response was classified under the domains of autonomy, beneficence and justice. Comparisons were made between classes and between vignettes. There was considerable variation between classes and the responses to different vignettes seem to indicate that different vignettes measure the various domains in different ways. It does appear that the use of vignettes is one way to measure aspects of ethical sensitivity in medical students but more study is required to clarify exactly what is being measured.

Two cases of accidental immersion hypothermia with different outcomes under identical conditions.

Two cases of accidental immersion hypothermia are presented, both occurring during the same aircraft ditching. One victim survived while the other patient died despite identical immersion time and environmental conditions. Pertinent literature is reviewed to attempt to explain the different patient outcomes. The most important discriminating factor appears to be skinfold thickness, which reflects body fat.

A method of quantifying sinus arrhythmia: parallel effect of respiration on P-P and P-R intervals.

1. The electrocardiogram was recorded for 3 min during spontaneous respiration in 70 subjects aged 15-86 years who were in sinus rhythm. Using a signal-averaging approach, the presence of respiratory variation of P-P intervals was analysed by multiple regression against a cosine function (cosinor analysis). 2. By cosinor analysis the phase of respiration when the intervals were longest was determined, together with the amplitude of the variation of the intervals around their mean value. 3. Respiratory variation of P-P intervals (respiratory sinus arrhythmia) was demonstrated in 84% of subjects; its amplitude decreased with age and respiratory rate. On average, the duration of P-P intervals varied by 2.8% around the mean, and the maximum duration occurred around the time of end-expiration. 4. By cosinor analysis, and allowing for variation of heart rate, P-R intervals showed an independent respiratory variation in 39% of cases, and its average amplitude was 1.2% around the mean. 5. The respiratory variation of P-R and P-P intervals showed similar phase relationships to respiration, suggesting that during respiration there is parallel alteration of sinoatrial and atrioventricular node function.

Paradoxical effect of respiration on ventricular rate in atrial fibrillation.

1. In 50 subjects with atrial fibrillation we have attempted to demonstrate variation of ventricular rate with respiration, as evidence of cardioregulatory reflex activity. 2. The electrocardiogram was recorded for 3 min during spontaneous respiration. The presence of respiratory variation of R-R intervals was analysed by multiple regression against a cosine function (cosinor analysis), making it possible to determine the phase of respiration when the intervals were longest. 3. Variation in ventricular rate with respect to respiration was demonstrated (P less than 0.05) in seven (14%) cases. On average, R-R intervals were longest at the end of inspiration; this contrasts with sinus rhythm where P-P, P-R and R-R intervals are longest around the time of end-expiration. 4. These results suggest that in atrial fibrillation the beat-to-beat ventricular rate may be under the influence of cardioregulatory reflexes, but the effect of respiration is weak and paradoxical.

The comparative efficacy of cimetidine and ranitidine in controlling gastric pH in critically ill patients.

The comparative efficacy of intravenous cimetidine and ranitidine in controlling gastric pH in 100 intensive care unit patients was assessed in a double blind, prospective, randomized study. The total number of gastric pH determinations and the number of pH determinations with pH less than five were recorded. Patients received either cimetidine or ranitidine via continuous infusion, with dosage adjustments for patients with renal insufficiency. Antacids were administered each time the gastric pH was less than five. There was no difference overall in the number of patients who had at least one gastric pH determination less than pH 5. There was however, a larger proportion of patients with greater than or equal to 10, greater than or equal to 15, greater than or equal to 20 and greater than or equal to 25 per cent of gastric pH determination less than pH 5 in the cimetidine group than in the ranitidine group. This difference was statistically significant for greater than or equal to 25 per cent. The drugs were well tolerated. Ranitidine was as effective as cimetidine and possibly more so in controlling gastric pH.

The University of Toronto head injury treatment study: a prospective, randomized comparison of pentobarbital and mannitol.

Fifty-nine patients were treated in a prospective, randomized comparison of pentobarbital and mannitol for the control of intracranial hypertension resulting from head injury. Patients with elevated intracranial pressure (ICP) after evacuation of intracranial hematomas were randomized to one of two treatment groups; mannitol initially or pentobarbital initially, followed by the second drug as required by further elevation of ICP. Similarly, patients with raised ICP but without hematomas requiring evacuation were randomly assigned to two treatment groups in an identical paradigm. Those with ICP elevation and no hematoma treated with pentobarbital as initial therapy had a 77% mortality compared to a 41% mortality for those with mannitol as initial treatment. Patients with evacuated hematomas had mortalities of 40% and 43% (no significant difference) for pentobarbital and mannitol respectively. In both no-hematoma and hematoma streams pentobarbital was less effective than mannitol for control of raised ICP. Multivariable statistical analysis indicates that pentobarbital coma is not better than mannitol for the treatment of intracranial hypertension and may be harmful in no-hematoma patients with intracranial hypertension after head injury.

Massive blood transfusion causing hypomagnesemia.

A case report and short retrospective study are presented which describe the clinical occurrence of hypomagnesemia in the setting of massive blood transfusion. Hypomagnesemia is an important electrolyte imbalance and in the massively transfused patient is most likely secondary to citrate toxicity.