Penelope T. Louis

Acute neuroradiologic findings in young children with inflicted or noninflicted traumatic brain injury

Abstract Acute CT/MRI findings were examined in a prospective, longitudinal study of 60 children 0–6 years of age hospitalized for moderate to severe traumatic brain injury (TBI). TBI was categorized as either inflicted (n=31) or noninflicted (n=29). Glasgow Coma Scale scores and perinatal history were comparable in both groups. Acute CT/MRI studies were visually inspected by a radiologist blind to group membership. Compared with the noninflicted TBI group, the inflicted TBI group had significantly elevated rates of subdural interhemispheric and convexity hemorrhages as well as signs of pre-existing brain abnormality, including cerebral atrophy, subdural hygroma, and ex vacuo ventriculomegaly. Intraparenchymal hemorrhage, shear injury, and skull fractures were more frequent after noninflicted TBI. Subarachnoid hemorrhage and infarct/edema occurred with comparable frequency in both groups. Characteristic acute neuroimaging findings of inflicted TBI included multiple extraaxial hemorrhages in addition to the mild atrophy, subdural hygromas, and ventriculomegaly that suggest prior brain abnormality.

Barbiturates and hyperventilation during intracranial hypertension

OBJECTIVE The purpose of this study was to determine the effect of hyperventilation alone and hyperventilation plus barbiturate therapy on intracranial pressure, global and regional cerebral blood flow rates, cerebrovascular resistance, and cerebral perfusion pressure in adult dogs with and without intracranial hypertension induced by epidural balloon. DESIGN Prospective, randomized, controlled study. SETTING An animal laboratory of a university hospital. Four sequential global and regional cerebral blood flow determinations were made in each animal during monitoring of heart rate and systemic arterial pressure, during respiratory control and arterial blood gas monitoring, intracranial pressure monitoring, and with or without inflation of an epidural balloon catheter. SUBJECTS Acute mongrel dogs obtained from the Baylor Center for Comparative Medicine. Five groups of animals were studied. In group 1, the response to hyperventilation was assessed in dogs without increased intracranial pressure. In group 2, the response to hyperventilation was assessed in animals with acute intracranial hypertension. In group 3, the response to hyperventilation plus barbiturate therapy was assessed in dogs without increased intracranial pressure. In group 4, the response to hyperventilation plus barbiturate therapy was assessed in dogs with acute increased intracranial pressure. In group 5, a group of dogs with increased intracranial pressure was treated with neither hyperventilation nor barbiturates. INTERVENTIONS Hyperventilation, hyperventilation plus barbiturate therapy, or no interventions were studied in these experimental paradigms. MEASUREMENTS AND MAIN RESULTS The main outcome measures were changes in intracranial pressure and/or changes in regional or total cerebral blood flow. A significant decrease in intracranial pressure and cerebral blood flow rate was produced by hyperventilation alone in groups with intracranial hypertension. Combined hyperventilation and barbiturate therapy resulted in a significant further decrease in cerebral blood flow rate in animals with normal and increased intracranial pressure, but no greater decrease in intracranial pressure was seen compared with treatment with hyperventilation alone. Cerebral perfusion pressures remained normal despite significant decreases in cerebral blood flow rates. CONCLUSIONS These studies suggest that barbiturate administration in this model of intracranial hypertension was no more effective in reducing increased intracranial pressure than hyperventilation alone.

Neuropathology of two fatal cases of measles in the 1988-1989 Houston epidemic.

The clinical course and autopsy findings of 2 patients with measles encephalitis that occurred during the 1988-1989 Houston epidemic are reported. A previously healthy 25-month-old boy had serologically-proved measles, hemophagocytic syndrome, and acute disseminated demyelinating encephalitis. A 19-year-old male with acute lymphocytic leukemia had proved measles pneumonia and acute hemorrhagic leukoencephalitis. These patients represent a broad spectrum of measles-induced immunopathic complications of the central nervous system.

Correlation of near infrared spectroscopy cerebral blood flow estimations and microsphere quantitations in newborn piglets

We compared cerebral blood flow (CBF) estimated using transmission mode near infrared spectroscopy (NIRS) and a modification of the Fick principle with CBF quantitations by radioactive microspheres (MSs) in newborn piglets. Thirteen piglets were studied during steady state, ischemia, and during two reflow periods. NIRS and MS flows were not significantly different during any measurement period. NIRS flows were compared to total brain blood flows and to regional brain blood flows quantitated with MSs and correlated best with temporal cortical flows. Linear regression analysis of the NIRS flows plotted against MS-quantitated temporal cortical flows showed r = 0.71. Thus, CBFs obtained with NIRS were not significantly different from, showed the same directional changes, and correlated acceptably with flows quantitated by MSs.

Brain Blood Flow Responses to Indomethacin during Hemorrhagic Hypotension in Newborn Piglets

Indomethacin has been shown to reduce cerebral blood flow and cerebral blood flow velocities in newborn infants and animals of various species. To answer the question of whether there may be a compromise of cerebral perfusion in hypotensive infants who have been treated with indomethacin, cerebral blood flow and cerebral vascular resistance were determined in 10 control and 16 indomethacin-treated 1-day-old piglets during (1) steady state conditions; (2) 10 min after the administration of saline or a 0.2-mg/kg dose of indomethacin; (3) 1 h after saline or indomethacin administration, and (4) 10 min after induction of moderate hemorrhagic hypotension. Mean arterial blood pressures increased immediately after the infusion of indomethacin in the experimental group. Cerebral blood flows did not change throughout the study despite hemorrhagic hypotension in controls; cerebral blood flows were significantly decreased 10 min after indomethacin infusion in the experimental animals. However, total and regional cerebral blood flows were not further decreased in the presence of moderate hypotension. Cerebral vascular resistance increased 10 min after indomethacin infusion but returned to steady state 1 h following the indomethacin dose. These results suggest that indomethacin lowers baseline cerebral blood flow, but does not impair cerebrovascular regulatory responses during acute, moderate hemorrhagic hypotension in the newborn piglet.

Use of the Natural Death Act in pediatric patients.

ObjectiveTo review the use of Natural Death Act declarations (living will procedures) in pediatric patients. The implementation of such declarations for children is now possible in six states, including Texas, by specific statutory provisions. DesignRetrospective study. SettingPediatric ICU in a university hospital. PatientsRecords of patients who had a Texas Natural Death Act declaration, either discussed and signed or discussed only, were studied. Patients who had another vehicle of limiting care (e.g., a do-not-resuscitate order) were excluded from the study. Measurements and Main ResultsReviewed characteristics included age, primary diagnosis, and concurrent complications. Also examined were who raised the issue of limiting care (parent or physician), the initial reaction of the other party, what support was withdrawn, what support was added, the final outcome (including the time from implementing limited care to death), and the description of witnesses.Discussions were held with parents of 17 patients, and 13 Natural Death Act declarations were actually implemented. In all but three instances, the patient died within 4 hrs from the time support was withdrawn. The main supports that were withdrawn were ventilators and catecholamines. In half of the cases, morphine sulfate was added for anticipated pain relief and sedation. All decisions were reached by close consultation between the family and the physicians, with the physicians raising the issue in 11 of the 17 cases and the family raising the issue in six cases. In 15 of the 17 patients, consultation with the Bioethics Committee was not necessary. The majority of difficulties involved resolving issues that beset patients with HIV infections, and finding appropriate witnesses as prescribed by the statute. ConclusionsWe conclude that the Natural Death Act works well in situations involving dying children and their parents. (Crit Care Med 1991; 19:901)

Cytochrome oxidase is decreased in piglet hippocampus following hypoxia-ischemia

We assessed cytochrome oxidase (CytOx) staining in sham-operated control piglets and in piglets subjected to 30 minutes of cerebral hypoxia-ischemia (H-I) plus 4 hours of reperfusion (REP). The 1-day-old piglets were sedated, anesthetized, and ventilated. Cerebral blood flows (CBFs) were quantitated using microspheres. H-I was induced by a combination of phlebotomy and cervical tourniquet; the brain was reperfused for four hours after 30 minutes of H-I. CBF was reduced during ischemia in experimental animals from 42+13 to 12+5 ml/min/100g. CytOx staining of hippocampal sections from 3 control and 3 experimental animals was compared. The staining of the stratum pyramidale neurons of the same portion of the CA1 sector in a single high power field was assessed in a blinded fashion in 4 corresponding sections from each animal, and graded from 0=no staining to 3=heavy staining. The results were compared using one-way analysis of variance. Cells with grade 3 staining were significantly more numerous in controls compared to H-I/REP animals (p=0.03). There were significantly more cells with no CytOx staining in the experimental animals (p=0.01). These findings suggest that CytOx staining in newborn piglet CA1 is a reliable method of assessing cell dysfunction after H-I.

Otakar Koldovsky, MD, PhD, Professor of Pediatrics

My friend died suddenly on April 5 in his home. In an e-mail message, Otakar wrote to me that he fell off a podium in New Zealand and then got up and presented his work, pointing out that he had fallen into another hole 40 years ago in Warsaw, and that within no time Stalin had died; he asked who was going to die this time. Well, it was Dr. Otakar Koldovsky himself. We shall always miss him, not only for his science but also for his humanity and his sense of humor. I met him in the fifties, when he started as a student im my laboratory in Prague. He very soon found his research feet and started to examine the development of the intestine in rats and human fetuses. For this work he was awarded a CIBA prize in London. Once, when visiting England, he was asked by the customs officer for the purpose of his trip. He replied: ‘To study the everted sac of Professor Smith.’ Our group was interested in long-term development, and it was Otakar, together with Dr. Kubat, who first showed that plasma cholesterol in the adult rat is conditioned by early nutrition. In 1968, many of us left Czechoslovakia for good. Otakar ended up in the Pediatric Department in Philadelphia, where he not only discovered new aspects of digestion, but at the same time studied to obtain an American qualification as a physician. This was hard

Barbiturates and Hyperventilation During Intracranial Hypertension

ObjectiveThe purpose of this study was to determine the effect of hyperventilation alone and hyperventilation plus barbiturate therapy on intracranial pressure, global and regional cerebral blood flow rates, cerebrovascular resistance, and cerebral perfusion pressure in adult dogs with and without intracranial hypertension induced by epidural balloon. DesignProspective, randomized, controlled study. SettingAn animal laboratory of a university hospital. Four sequential global and regional cerebral blood flow determinations were made in each animal during monitoring of heart rate and systemic arterial pressure, during respiratory control and arterial blood gas monitoring, intracranial pressure monitoring, and with or without inflation of an epidural balloon catheter. SubjectsAcute mongrel dogs obtained from the Baylor Center for Comparative Medicine. Five groups of animals were studied. In group 1, the response to hyperventilation was assessed in dogs without increased intracranial pressure. In group 2, the response to hyperventilation was assessed in animals with acute intracranial hypertension. In group 3, the response to hyperventilation plus barbiturate therapy was assessed in dogs without increased intracranial pressure. In group 4, the response to hyperventilation plus barbiturate therapy was assessed in dogs with acute increased intracranial pressure. In group 5, a group of dogs with increased intracranial pressure was treated with neither hyperventilation nor barbiturates. InterventionsHyperventilation, hyperventilation plus barbiturate therapy, or no interventions were studied in these experimental paradigms. Measurements and Main ResultsThe main outcome measures were changes in intracranial pressure and/or changes in regional or total cerebral blood flow. A significant decrease in intracranial pressure and cerebral blood flow rate was produced by hyperventilation alone in groups with intracranial hypertension. Combined hyperventilation and barbiturate therapy resulted in a significant further decrease in cerebral blood flow rate in animals with normal and increased intracranial pressure, but no greater decrease in intracranial pressure was seen compared with treatment with hyperventilation alone. Cerebral perfusion pressures remained normal despite significant decreases in cerebral blood flow rates. ConclusionsThese studies suggest that barbiturate administration in this model of intracranial hypertension was no more effective in reducing increased intracranial pressure than hyperventilation alone. (Crit Care Med 1993; 21:1200–1206)