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Biomedical subjects

N Kissoon

Publications and source records attributed to N Kissoon.

At least 19 recordsLinked to original sources
PubMed1992

Relationship of cross-brain oxygen content difference, cerebral blood flow, and metabolic rate to neurologic outcome after near-drowning.

We evaluated the relationship of global cerebral blood flow, cross-brain oxygen content difference, cerebral metabolic rate for oxygen, intracranial pressure, and cerebral perfusion pressure to functional neurologic outcome in 12 comatose children on 2 consecutive days after near-drowning. Five children survived with functional neurologic outcome; five died and two survived with severe neurologic damage. Children who survived with functional neurologic outcome had a significantly higher cross-brain oxygen content difference (7.89 +/- 2.62 vs 3.91 +/- 1.59 ml/dl; p = 0.028) at 24 hours and a higher cerebral metabolic rate for oxygen 48 hours after admission (3.19 +/- 2.86 vs 0.96 +/- 0.45 ml/100 gm per minute; p = 0.030) compared with those who died or survived in a damaged state. There were no significant differences in global cerebral blood flow, intracranial pressure, and cerebral perfusion pressure between groups at either 24 or 48 hours. Our preliminary data suggest that a higher cross-brain content difference value is an important early variable associated with functional neurologic recovery after near-drowning. However, a single cross-brain oxygen content difference value must be interpreted with caution because considerable variability may occur among patient groups.

Adolescent↗
PubMed1992

Use of comparison radiographs in the diagnosis of traumatic injuries of the elbow.

STUDY OBJECTIVE: To determine whether comparison radiographic views of the uninjured elbow result in increased diagnostic accuracy in elbow trauma. DESIGN: Physicians were provided with a short clinical summary and asked to interpret radiographs of the injured elbow or of both the injured and the uninjured elbow in a randomized fashion. SETTING: The radiology department in a university hospital. METHODS: Fifty sets of radiographs from 25 children with elbow injuries were reviewed by two residents, two emergency physicians, and one pediatric radiologist using a standard classification of injuries. For each child, there were two sets of radiographs: one of the injured elbow and one of both the injured and the uninjured elbow. Descriptive statistics were used to report the results. kappa statistics were used to determine interobserver and intraobserver agreement. Missed diagnoses were divided into those that were clinically relevant and those that were not. RESULTS: The overall percentage of correct diagnoses (one versus two elbow radiographs) were as follows: residents, 69% versus 70%; emergency physicians, 62% versus 67%; and pediatric radiologist, 74% versus 72% (P greater than .05). kappa scores for interobserver variability and intrarater agreement were in the moderate range (.383 to .805; kappa, .08). Clinically relevant diagnoses were missed by trainees and emergency physicians regardless of whether radiographs of just the injured elbow or both the injured and the uninjured elbow were interpreted. Incorrect radiograph interpretations were due to false-positives in 17 of 23 cases. CONCLUSION: Comparison radiographs of the uninjured elbow did not improve diagnostic accuracy in elbow trauma in the pediatric emergency department.

Adolescent↗
PubMed1992

Comparison of continuous versus intermittent furosemide administration in postoperative pediatric cardiac patients.

OBJECTIVE: To compare the effects of furosemide administered by intermittent iv infusion vs. continuous iv infusion on urine output, hemodynamic variables, and serum electrolyte concentrations. DESIGN: Prospective, randomized trial. SETTING: Pediatric ICU. PATIENTS: Postoperative pediatric cardiac patients. INTERVENTIONS: Patients were assigned to either the continuous iv infusion or the intermittent infusion groups. The intermittent group received 1 mg/kg iv of furosemide every 4 hrs to be increased by 0.25 mg/kg iv every 4 hrs to a maximum of 1.5 mg/kg iv if the urine output was less than 1 mL/kg.hr. The continuous infusion group received an initial furosemide dose of 0.1 mg/kg iv (minimum 1 mg) followed by an iv infusion rate of 0.1 mg/kg.hr of furosemide to be doubled every 2 hrs to a maximum of 0.4 mg/kg.hr if the urine output was less than 1 mL/kg.hr. MEASUREMENTS AND MAIN RESULTS: Demographic variables, fluids, electrolyte and inotropic requirements were the same in both groups. A significantly (p = .045) lower daily dose of furosemide (4.90 +/- 1.78 vs. 6.23 +/- 0.62 mg/kg.day) in the continuous iv infusion group produced the same 24-hr urine volume as that of the intermittent group. There was more variability in urine output in the intermittent group as well as more urinary losses of sodium (0.29 +/- 0.15 vs. 0.20 +/- 0.06 mmol/kg.day, p = .0007) and chloride (0.40 +/- 0.20 vs. 0.30 +/- 0.12 mmol/kg.day, p = .045). CONCLUSION: Furosemide administered by continuous iv infusion is advantageous in the post-operative pediatric patient because of a more controlled and predictable urine output with less drug requirement and less urinary loss in sodium and chloride.

Cardiac Surgical Procedures↗
PubMed1992

An evaluation of the physical and functional characteristics of resuscitators for use in pediatrics.

OBJECTIVE: To evaluate the physical and functional characteristics of pediatric self-inflating resuscitators. DESIGN: Tested under simulated clinical conditions. Results were analyzed by descriptive analysis. SETTING: A pulmonary laboratory in a university hospital. METHODS: Eight new pediatric self-inflating resuscitators were obtained from the manufacturers and evaluated for functional characteristics including: a) fraction of delivered oxygen at 10 L/min and a tidal volume of 300 mL; b) maximum stroke volume against no resistance; and c) maximum cycling frequency at -5 degrees C, 20 degrees C, and 48 degrees C. The resuscitators were also evaluated for physical characteristics, including potential for misassembly, pressure relief valves, expiratory valve leak, and inspiratory resistance. RESULTS: All resuscitators met the minimum standards of the Canadian Standards Association and American Standards for Testing of Materials. However, one bag cycled at only 32 breaths/min at -5 degrees C, marginally within accepted standards. Only five self-inflating resuscitators had pop-off valves. These valves malfunctioned, with valve activation occurring well above the accepted standards. Three of the self-inflating resuscitators could be misassembled for use. Four of the resuscitators were unable to deliver tidal volumes required for preoxygenation in a 20-kg child. CONCLUSIONS: While these self-inflating resuscitators met the minimum standards, they are all unable to deliver 100% oxygen. One unit is probably not appropriate in the out-of-hospital setting when ambient temperatures are less than 0 degrees C. Those resuscitators that can be misassembled are dangerous in unskilled hands. In addition, reliance on pop-off valve activation to limit airway pressure is dangerous.

Child↗
PubMed1992

Is a full team required for emergency management of pediatric trauma?

Pediatric trauma centers often do not meet the guidelines requiring a trauma team as recommended by the American Academy of Pediatrics (AAP). We reviewed our experience with a team consisting of a pediatric emergency physician, resident, nurse, and respiratory therapist. The surgical and pediatric critical care residents and staff were available within 5 minutes. We conducted a retrospective chart review of 146 patients (aged 8.1 +/- 4.8 years) between 1987 and 1989, with Injury Severity Scores (ISS) greater than or equal to 16 or admitted to the pediatric critical care unit. The time of presentation, surgical services consulted, and the nature of the injury were obtained from chart review. The Pediatric Trauma Score (PTS), the Revised Trauma Score (RTS), the Injury Severity Score (ISS), Glasgow Coma Scale (GCS) score, and Pediatric Risk of Mortality (PRISM) were used to determine the severity of insult and physiologic derangement on admission. The Modified Injury Severity Score (MISS) was determined and the Delta score for Disability Assessment was assigned at discharge. The Delta score was also determined at 3-month intervals up to one year. The probability of survival (Ps) was calculated, using the ISS and RTS. The Z statistic for this group of patients was then determined, using the Major Trauma Outcome Study (MTOS) methodology. The percentages of patients who were normal, disabled, and dead were 61%, 31.5%, and 7.5%, respectively, at 6 months follow-up. Eleven deaths were expected based on PRISM and TRISS analysis. Our mortality and morbidity figures were comparable with those of centers with teams based on AAP guidelines.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Acute testicular pain: Henoch-Schönlein purpura versus testicular torsion.

A skilled examiner may not be able to exclude testicular torsion by physical examination maneuvers in a patient who presents with acute scrotal pain. Diagnostic adjunctive studies may be of assistance. However, if a diagnosis cannot be established with certainty, surgical exploration is warranted. Patients with Henoch-Schönlein purpura who present with a vascular eruption on the scrotum, lack a rash elsewhere, and have no arthritis or hematuria are likely to be explored.

Acute Disease↗
PubMed1992

Triage and transport of the critically ill child.

The aim of critical care transport services is the provision of care prior to and during transportation, similar to that offered in the tertiary care intensive care unit. This can only be achieved by a well prepared and equipped team dedicated to provision of this care. Appreciation of the disease conditions and adverse physiologic events likely to be encountered is necessary for the success of the team. Patient demographics and diseases in various geographic areas have been reported in the past few years. But, at the present time, team composition, responsibilities, and training requirements have not been well defined. In addition, there are no validated scoring systems to assist in team composition, triage of patients, or in the meaningful evaluation of mortality statistics. Within the next few years, one can expect to see genuine attempts made to address some of these issues.

Body Temperature Regulation↗
PubMed1991

Cerebral blood flow, cross-brain oxygen extraction, and fontanelle pressure after hypoxic-ischemic injury in newborn infants.

The relationship between mean arterial pressure, intracranial pressure, cerebral blood flow, cross-brain oxygen extraction, cerebral metabolic rate, and outcome was studied during therapy in nine neonates on 3 consecutive days after severe hypoxic-ischemic cerebral injury. Cross-brain oxygen extraction was significantly higher (5.06 +/- 0.5 vs 2.05 +/- 0.8 ml/dl; p = 0.012) in the five neonates who survived with normal neurologic outcome than in the four who died or sustained severe brain damage. In contrast, global cerebral blood flow in the five neonates with normal neurologic outcome was significantly lower (25.6 +/- 8.2 vs 83.2 +/- 44.9 ml/100 gm brain/min; p less than 0.05) during the study period. The differences in cross-brain oxygen extraction and global cerebral blood flow between infants who had neurologic recovery and those who died or sustained brain damage occurred in the presence of acceptable values for intracranial pressure, mean arterial pressure, and cerebral perfusion pressure. Our preliminary data suggest that cross-brain oxygen extraction and possibly global cerebral blood flow may be important variables associated with severe neuronal injury and death after hypoxic-ischemic cerebral injury.

Asphyxia Neonatorum↗
PubMed1991

Evaluation of performance characteristics of disposable bag-valve resuscitators.

OBJECTIVE: To evaluate the performance characteristics of disposable bag-valve resuscitators. DESIGN: Single and multitrial tests under simulated clinical conditions. Results of multitrial tests were analyzed by multivariate analysis of variance. SETTING: A pulmonary laboratory in a university hospital. METHODS: We evaluated eight DRs to determine: a) physical characteristics, including the potential for misassembly; b) FIO2 of 1.0 and flow rates of 10 L; c) tidal volume (VT) (male and female operators) using one and two hands; and d) cycling rates at 5 degrees, 20 degrees, and 48 degrees C. RESULTS: All resuscitators met the minimum requirements of the Canadian Standards Association and the American Society for Testing and Materials. However, the CPR and LSP could be assembled incorrectly for use. Three units (B Sav, Pulm, and MPR) delivered significantly less than 80% oxygen (overall p less than .05). Significant increases were seen in VT using two hands vs. one hand (1176 vs. 960 mL, p less than .001) and males vs. females using two hands (1284 vs. 1102 mL, p less than .02). One unit (B Sav) could only be used with two hands. The maximum cycling rates for all units increased significantly (p less than .05) with an increase in temperature from -5 degrees to 20 degrees to 40 degrees C. However, two units (Bag E and MPR) failed to deliver 20 breaths/min at -5 degrees C, while the B Sav and Pulm valves became dysfunctional at 48 degrees C. CONCLUSIONS: While these DRs meet the minimum standards, they should be chosen carefully and evaluated before application in the clinical environment.

Disposable Equipment↗
PubMed1991

Comparison of a topical mixture of lidocaine and prilocaine (EMLA) versus 1% lidocaine infiltration on wound healing.

We compared a eutectic mixture of lidocaine and prilocaine (EMLA, Astra Pharmaceuticals, Inc) with 1% lidocaine infiltration to determine the effect on wound healing in a prospective single blind study using the rat model. Thirty-six wounds were assessed. No clinical or histologic evidence of infection or necrosis was present in any wound. Five wounds (two in the lidocaine and three in the EMLA group, P = 1.0) demonstrated a widened scar owing to healing by secondary intention following suture disruption. There was no significant difference between groups in the degree of inflammation (P = 0.08). We conclude that EMLA does not affect wound healing adversely and is comparable to 1% lidocaine infiltration in the animal model. Further study to determine its anesthetic effect in laceration repair is presently being undertaken.

Administration, Topical↗
PubMed1990

Pediatric trauma: differences in pathophysiology, injury patterns and treatment compared with adult trauma.

Although multiple trauma remains the leading cause of death among children, fewer resources and less attention have been directed to treatment of the injured child than to treatment of the injured adult. Insufficient training of medical personnel and hence lack of expertise in the management of injured children are factors contributing to disability and death in such children. Although the principles of resuscitation of injured children are similar to those for adults, appreciation of the differences in cardiorespiratory variables, airway anatomy, response to blood loss, thermoregulation and equipment required is essential for successful initial resuscitation. Cerebral, abdominal and thoracic injuries account for most of the disability and death among injured children. Cerebral damage may be due to secondary injuries to the brain and is potentially preventable. The need to preserve the spleen in children complicates the management of abdominal trauma. Although children usually have large cardiorespiratory reserves, they are likely to need airway control and ventilation with thoracic injuries. The psychologic effect of trauma may pose long-term problems and needs close follow-up.

Abdominal Injuries↗
PubMed1990

Prototype volume-controlled resuscitator for neonates and infants.

Twenty-five infants receiving assisted ventilation in an ICU were manually ventilated for 5-min periods using either a new prototype volume-controlled resuscitator (VCR) or a standard self-inflating resuscitator (SIR). Variables monitored during these 5-min periods included heart rate, respiratory rate, mean arterial pressure, mean airway pressure (Paw), end-tidal CO2 (PetCO2), pulse oximetry oxygen saturation, PaO2, and PaCO2. Significant differences in posttrial values for the following variables were: a) PetCO2 (31.2 +/- 9.1 vs. 25.6 +/- 8.2 torr, p less than .001); b) PaCO2 (38.0 +/- 4.9 vs. 33.2 +/- 6.7 torr, p less than .01); and c) pH (7.4 +/- 0.6 vs. 7.5 +/- 0.1, p less than .04) at comparable Paw (9.5 +/- 7.6 vs. 8.0 +/- 6.0, NS). Eighty-four percent (21/25) of infants in the VCR group had normal PaCO2 values (35 to 45 torr) while only 44% (11/25) in the SIR group achieved normocarbia (p less than .001). Measurements of the highest (Pmax) and lowest (Pmin) inspiratory pressure (cm H2O) in 15 patients demonstrated marked variation in Pmax with the SIR. Differences in Pmax (SIR minus VCR) were significant (10.8 +/- 3.7, p less than .02) but not in Pmin (0.5 +/- 3.5, NS). Our study demonstrates that ventilation with the VCR resulted in less hyperventilation with minimal pressure variability as compared with the SIR. Further studies in the neonate are warranted.

Equipment Design↗
PubMed1989

The critically ill child in the pediatric emergency department.

A retrospective study of the charts of all critically ill patients visiting our pediatric emergency department over an 18-month period was conducted to determine age, diagnosis, time of presentation to the pediatric ED, Physiologic Stability Index (PSI) and Therapeutic Intervention Scoring System (TISS) score, and eventual outcome. Eighty percent of critically ill patients were less than 6 years old. Of these patients, 35% had neurological problems, 23% had lower airway disease, and 15% had upper airway obstruction. Forty-one percent of children presented during the day shift, 33% during the evening shift, and 26% at night. One hundred fifteen patients survived to discharge from the intensive care unit; eight patients died. A statistically significant difference in retrospectively assigned PSI scores in nonsurvivors (18.1 +/- 6.5) compared with those in survivors (5.2 +/- 3.5) was observed. There was also a statistically significant difference in retrospectively assigned TISS scores in nonsurvivors (32.4 +/- 3.2) compared with those in survivors (13.5 +/- 2.1). Implications for physicians involved in the emergency care of critically ill children and for designs of pediatric advanced life support programs are outlined.

Acute Disease↗
PubMed1989

Jugular venous bulb catheterization in infants and children.

Cross-brain oxygen extraction may be altered by coma, hyperventilation, hypothermia, or barbiturates, and has been demonstrated in adults and more recently in children to be related to functional neurologic recovery after a variety of brain injuries. However, measurement of cross-brain oxygen extraction in children is currently not a part of routine clinical care, partly because there have been no published attempts relating the technique of jugular venous bulb (JVB) catheterization and its complication in children. We catheterized the JVB to measure cerebral venous oxygen content and calculate cross-brain oxygen extraction in 26 deeply comatose neonates and children ranging in age from a few hours to 14 yr. Bedside catheterization using the Seldinger technique was successful in 25 children, with standard venous cutdown necessary in the remaining child. All JVB catheterizations were performed with parental consent and during continuous monitoring of the intracranial (ICP) or fontanelle, as well as arterial, pressure. ICP was not significantly altered by the cannulation procedure in any of the children studied, although the cannulation occurred early in the child's course when ICP was well controlled. Inadvertent carotid artery puncture with bleeding controlled by local pressure occurred in four children, and catheter malposition was confirmed on lateral skull xray in two others. Jugular venous bulb catheters remained in place for 2 to 7 days (average 3) and malfunction or obstruction of the catheter did not occur. Organisms were grown from three of 26 catheter tips submitted for culture, with peripheral blood cultures also positive for the same organisms in two of these.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Usefulness of head injury instruction forms in home observation of mild head injuries.

We prospectively studied a group of patients with mild head injury discharged for home observation to determine whether written instructions assisted in recall of signs and symptoms, increased patient satisfaction, or resulted in any additional benefit over verbal explanations alone. We also evaluated the level of comprehension required to understand the written instructions in their present form. Over a three-month period, 72 patients (43 male, 29 female) with a mean age of 4.4 (SD +/- 3.9) years were studied. In addition to verbal explanations for all parents, 38 parents received written instructions. Each group remembered 4/7 (57%) of signs and symptoms and was equally satisfied with verbal explanations. The majority (84%) of parents who received instruction sheets intended to keep these for further reference. Low recall of two instructions may be due to poor comprehension of the language used. We conclude that written instructions (1) did not add significantly to recall, (2) may provide reassurance to parents, and (3) need to be written in simple lay terms in order to be understood by the parents/patients served.

Child↗