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Biomedical subjects

N Kissoon

Publications and source records attributed to N Kissoon.

At least 37 records · Page 2Linked to original sources

Use of intraosseous blood to assess blood chemistries and hemoglobin during cardiopulmonary resuscitation with drug infusions.

OBJECTIVE: To compare intraosseous with central venous blood samples for biochemical analyses and hemoglobin levels during cardiopulmonary resuscitation (CPR) and during cardiopulmonary resuscitation with infusion of sodium bicarbonate, epinephrine, and saline boluses through the intraosseous site. DESIGN: Prospective, complete repeated measures study. SETTING: An animal laboratory at a university medical center. SUBJECTS: Thirty-two piglets (mean weight, 30 [range, 24-35] kg). INTERVENTIONS: Animals were anesthetized, instrumented, and subjected to hypoxic cardiac arrest. An intraosseous cannula was inserted into the tibia, and animals were randomly assigned to one of five groups: heparinized saline (n = 6), epinephrine infusions only (n = 6), saline infusions only (n = 6), sodium bicarbonate infusions only (n = 8), and epinephrine, saline, and sodium bicarbonate infusions through the same site (n = 6). CPR (chest compressions and mechanical ventilation) was performed in all groups. Simultaneous blood samples were taken from the central venous and intraosseous sites before arrest and after 5 and 30 mins of CPR. MEASUREMENTS AND MAIN RESULTS: There were no differences (p < .05) in sodium, potassium, magnesium, lactate, and calcium values of intraosseous and central venous blood at the baseline and during 5 mins of CPR with infusions through the intraosseous cannula. At 30 mins, differences were apparent in magnesium, potassium, and sodium values between groups when the intraosseous cannula was used for infusions as well as sampling. Intraosseous potassium, glucose, and magnesium values were lower and sodium values were higher than central venous blood levels. No differences were seen at all sampling intervals if small-volume heparinized saline was given through the intraosseous site. Hemoglobin values were lower in the intraosseous group after 30 mins of CPR and infusions through the intraosseous site. After 30 mins of CPR, all hemoglobin values from the intraosseous site were <10 g/100 mL. CONCLUSION: Intraosseous and central venous blood biochemical and hemoglobin values were similar during hemodynamic stability and throughout 30 mins of resuscitation if no drugs were given through the intraosseous site. However, differences existed after 30 mins of CPR and infusions through the intraosseous site. Laboratory values may be erroneous when intraosseous blood is used during periods of resuscitation of >5 mins if drugs and fluid boluses have also been infused through the site. For reliable values, an intraosseous site for sampling only may be reasonable.

Animals↗

Acid-base status of blood from intraosseous and mixed venous sites during prolonged cardiopulmonary resuscitation and drug infusions.

OBJECTIVES: a) To determine the relationship of acid-base balance (pH, PCO2) of blood samples from the intraosseous and the mixed venous route during prolonged cardiopulmonary resuscitation; b) to compare the effect of separate infusions of epinephrine, fluid boluses, or sodium bicarbonate through the intraosseous sites on the acid-base status of intraosseous and mixed venous blood during cardiopulmonary resuscitation; and c) to compare pH and Pco2 of intraosseous and mixed venous blood samples after sequential infusions of fluid, epinephrine, and sodium bicarbonate through a single intraosseous site. DESIGN: Prospective, randomized study. SETTING: Animal laboratory at a university center. SUBJECTS: Thirty-two mixed-breed piglets (mean weight, 30 kg). INTERVENTIONS: Piglets were anesthetized and prepared for blood sampling and cardiopulmonary resuscitation. After anoxic cardiac arrest, ventilation was resumed and chest compression was resumed. Blood gas samples from the pulmonary artery and both intraosseous sites were obtained simultaneously at baseline, at cardiac arrest, and at 5, 10, 15, 20, and 30 mins of cardiopulmonary resuscitation for group 1 (control group) and after drug (epinephrine and sodium bicarbonate) and saline infusions via one of the intraosseous cannulas in groups 2 through 5. MEASUREMENTS AND MAIN RESULTS: We found no differences between intraosseous and mixed venous pH and Pco2 during periods of <15 mins of cardiopulmonary resuscitation. However, this relationship was not maintained during prolonged cardiopulmonary resuscitation and after bicarbonate infusion. After large volume saline infusion, the pH and Pco2 of mixed venous and intraosseous blood were similar. During epinephrine infusion, the relationship between intraosseous and mixed venous pH and Pco2 was similar to that found in the control group. CONCLUSIONS: The intraosseous blood sample could be used to assess central acid-base balance in the early stage of arrest and cardiopulmonary resuscitation of <15 mins. However, during cardiopulmonary resuscitation of longer duration, drug infusions may render the intraosseous site inappropriate for judging central acidosis.

Acid-Base Equilibrium↗

Status epilepticus: current concepts.

Status epilepticus (SE) is a common pediatric emergency encountered in the prehospital situations and in the emergency administration of anticonvulsants, which will cause the seizures to cease. Although prognosis is primarily determined by the etiology, the duration of SE and therapy administered have unequivocal impact. If the seizures last longer than 1 hour, homeostatic mechanisms may start to fail. A dynamic multidisciplinary approach is essential in seizure management. The emergency physician has a unique responsibility to provide state-of-the art therapy and individualize the involvement of other services. The input of the pediatric intensive care physician is critical and assumes a major role if the patient fails to respond to first-line therapy. The treatment of refractory status epilepticus requires labor-intensive hemodynamic support and suppression of central nervous system, with either an anesthetic agent or a barbiturate. There is an urgent need to formulate guidelines for management of refractory status epilepticus.

Anticonvulsants↗

Submersion injuries in children and adults.

Drowning and near drowning remain a common cause of childhood death and disability. Toddlers aged one through four drown in private swimming pools. Submersions greater than 10 minutes and lack of CPR at the scene or the need for greater than 20 minutes of resuscitation portends a poor prognosis. Management of respiratory failure without neurologic impairment has the most successful outcome. Prevention of drowning morbidity is dependent on constant parental supervision, and immediate and expert CPR.

Adolescent↗

Fat embolism with the use of intraosseous infusion during cardiopulmonary resuscitation.

The objective of this prospective study was to assess the incidence and magnitude of fat emboli after cardiopulmonary resuscitation and intraosseous infusions. An animal laboratory at a university center was used to study 33 mixed-breed piglets. The piglets underwent hypoxic cardiac arrest followed by chest compressions and mechanical ventilation for a minimum of 30 minutes. The animals were divided in groups: group 1 (n = 5), which had no intraosseous cannulas, group 2 (n = 6), which had intraosseous cannulas with infusion, groups 3 (n = 6), 4 (n = 6), and 5 (n = 8), which had intraosseous cannulas with infusion of epinephrine, normal saline, and sodium bicarbonate respectively, and group 6 (n = 2), which was a sham group with no intraosseous cannulas and no cardiopulmonary resuscitation. At cessation of cardiopulmonary resuscitation, representative lung samples were collected from upper and lower lobes of each lung and observed for fat globules and bone marrow elements. Fat globules were seen in the peribronchial blood vessels and intravascular areas throughout all lung fields of groups 1 through 5. There was no difference in appearance or distribution of fat globules among the 5 treatment groups. Analysis of variance showed no statistical significance (P < 0.05) within or among groups 1 through 5. The use of the intraosseous cannula for infusion of emergency drugs and fluids did not increase the magnitude of fat embolization over cardiopulmonary resuscitation alone in this animal model. The benefits of using this procedure in critically ill children as a means of rapid vascular access for resuscitation is well established. However, the risk of fat embolism in this population needs further study.

Analysis of Variance↗

Intraosseous and central venous blood acid-base relationship during cardiopulmonary resuscitation.

OBJECTIVE: The objectives of this study were: 1) to determine whether obtaining intraosseous (IO) blood samples was practical during cardiopulmonary resuscitation (CPR), and 2) to compare the acid-base status (pH and partial pressure of CO2 (PCO2) of venous and IO blood during CPR. DESIGN: A prospective repeated measure study. SETTING: An animal laboratory at a university medical center. INTERVENTIONS: Nine mixed breed piglets (mean weight 43 kg) were anesthetized, tracheotomized, and placed on a ventilator (Siemens 900C Elema, Sweden). Placement of a pulmonary artery catheter was done via a surgical incision in the neck. An IO cannula was then placed in the tibial marrow cavity. The animals were positioned under a mechanical thumper (Thumper, Michigan Instruments, Grand Rapids, MI) for chest compressions. Blood gases were analyzed during steady state (baseline) after five minutes of ventricular fibrillation and during CPR at seven, nine, 11, 13, 15 and 18 minutes. MAIN RESULTS: Blood samples for acid-base analysis were easily obtained from the IO sites during all sampling times. Mixed venous blood was slightly more acidic than IO blood, especially at 13, 15, and 18 minutes. However, there were no significant differences in pH and Pco2 values between IO and central venous (CV) gases at all time intervals except the PCO2. At nine minutes, a significant difference (P < 0.006) was found in PCO2 (59 +/- 4 vs 47 +/- 5 torr) for the CV versus IO sample, respectively. As the duration of CPR progressed, the differences in PCO2 between IO and CV sites were clinically relevant (though not statistically significant). CONCLUSION: Obtaining blood from the IO site is practical during CPR. The divergence in values as CPR progresses suggests that, during longer periods of CPR, IO blood may reflect local acidosis and yield lower PCO2 and higher pH values that CV blood. This finding may limit the usefulness of IO blood to judge acid base status as CPR progresses.

Animals↗

Pediatric and neonatal critical care transport: a comparison of therapeutic interventions.

OBJECTIVE: To compare the therapeutic interventions provided to newborn and pediatric patients by a dedicated combined neonatal pediatric critical care transport team. METHOD: From November 1987 through December 1989 we prospectively compared the number of therapeutic interventions performed by the critical care transport team on newborns and pediatric patients. The transport team (critical care physician [PL3 or greater], pediatric respiratory therapist, critical care nurse), recorded all therapeutic interventions, including both procedural and pharmacologic, for 213 newborn and 149 pediatric consecutive transports. Data were analyzed by analysis of variance or chi 2 statistic. RESULTS: All patients were admitted to either the pediatric or the neonatal intensive care unit, and over 80% of both age groups received assisted ventilation. Newborns commonly suffered from respiratory diseases (159/213), while pediatric patients suffered from respiratory (52/149), central nervous system (28/149), and traumatic conditions (37/149). Airway maintenance procedural interventions (intubation, ventilation) were the commonest in both groups, although more frequent in neonates. Neonates received antibiotics and morphine (P < 0.05) while pediatric patients received anticonvulsants and respiratory drugs (P < 0.05) more frequently. Newborns received significantly more interventions than pediatric patients (average 3.56 vs 2.93, P < 0.05). Newborns also received significantly more procedural interventions (2.06 vs 1.36, P = < 0.05) including intubation (34.7% vs 15.4%, P < 0.05) and the initiation of mechanical ventilation (38% vs 22%, P < 0.05). CONCLUSION: Overall, newborns received more interventions, including intubation, and ventilation from the transport team than did pediatric patients. Our data suggest that combined pediatric neonatal transport teams should be prepared to intervene in a wide range of conditions from preterm respiratory distress to the multiply traumatized adolescent.

Child↗

Influence of referring physicians on interventions by a pediatric and neonatal critical care transport team.

The objective of this study was to determine the influence of: a) pediatrician versus nonpediatrician referrals on a transport team's therapeutic interventions and b) referring physician's year of graduation on interventions performed by the transport team. From November 1987 through December 1989 we prospectively compared the therapeutic interventions performed by the critical care transport team on newborns and pediatric patients with the referring physician's specialty and year of graduation. The transport team (critical care physician [PL3 or greater], registered respiratory therapist, critical care nurse), recorded all therapeutic interventions, including both procedural and pharmacologic, for 213 newborn and 149 consecutive pediatric transports. Referring physicians were categorized as pediatricians and nonpediatricians. Data were analyzed by analysis of variance, chi2, or linear regression. All patients were admitted to either the pediatric or the neonatal intensive care unit, and over 80% of both age groups received assisted ventilation. Newborns referred by nonpediatricians required significantly more procedural interventions (2.64 vs 1.91, P = 0.016) than those referred by pediatricians. The opposite relationship was observed among pediatric patients in that children referred by pediatricians received more frequent intervention (P = 0.008) than those referred by nonpediatricians. There was a significant inverse relationship between the referring physicians year of medical school graduation and the number of therapeutic interventions (total interventions = 6.17 - 0.040 x graduation year, P = 0.01) and procedural interventions (procedural interventions = 3.54 - 0.024 x graduation year, P = 0.01). We found that the referring physicians' medical training affected the number of interventions their patients received. Similarly, patients were likely to receive more interventions if the referral physicians training was not recent. These data have educational implications and support the concepts of continuing medical education, recertification, and maintenance of skills among physicians providing care to critically ill newborns and pediatric patients.

Critical Care↗

The evaluation of pediatric trauma care using audit filters.

OBJECTIVE: To evaluate the experience of a pediatric trauma system with specific reference to prehospital, trauma center resuscitation, and critical care phases of treatment. DESIGN: Descriptive review of concurrent audit. SETTING: A tertiary care referral adult and pediatric trauma center. PATIENTS: All pediatric trauma victims in the trauma registry (includes patients < or = 14 years old, who died or were hospitalized for > or = 24 hours). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Age, pediatric trauma, injury severity, and Glasgow Coma Scale scores as well as outcome (death or discharge disability score) were analyzed. Primary filters (those with the potential to contribute to morbidity and mortality), secondary filters (minor deviations from care), missed injuries and all deaths were reviewed. Of 250 patients in the registry, 20 died. One hundred thirteen had filters, with 49 having primary filters (34 with one, 14 with two, and one with four filters). Fifty percent of primary filters occurred in the prehospital phase of care with inadequate airway management and venous access accounting for 60%. Overall, primary filters occurred more commonly in patients with severe injuries (lower Pediatric Trauma and Glasgow Coma Scale and higher Injury Severity scores). Primary filters were also statistically more common in patients who died or who were disabled. In three patients (25%) who died, our review suggested that filters may have contributed to demise. Missed injuries were mostly extremity fractures and did not contribute to mortality or long-term morbidity. CONCLUSION: Deviations from care occur, even in a dedicated pediatric trauma system. Mortality of and by itself is not an adequate indicator of the quality of function of a trauma system. Since most primary filters occurred outside of the trauma center, improvement in trauma outcome may be expected with better training of personnel involved in the prehospital care of injured children. A comprehensive review of death and disability should include audit filters of prehospital care, triage, definitive care, and rehabilitation.

Child↗

Assessment of respiratory distress in the asthmatic child: when should we be concerned?

The physician caring for the acutely ill asthmatic child has a wide variety of signs and systems to assist in assessment. An assessment of the severity of the disease should be based on the medical history, and signs and symptoms due to hypoxia on various target organs. Laboratory evaluation, while helpful, has limited applicability in the young child but should be used as an adjunct to clinical assessment where necessary. Based on the history, physical examination, and laboratory assessment (when appropriate), acute asthma symptoms should be categorized as mild, moderate, or severe. Treatment then can be tailored to disease severity.

Acute Disease↗

Comparison of transtracheal and extravascular Doppler determinations of stroke volume and cardiac output at various states of volume loading in piglets.

OBJECTIVE: To assess the applicability of a new technology in neonates. Transtracheal Doppler and extravascular Doppler determinations of stroke volume and cardiac output were compared with thermodilution measurements at various states of volume loading in an animal model. DESIGN: Prospective, descriptive study. SETTING: Animal research laboratory at a university medical center. SUBJECTS: Fourteen newly weaned piglets, weighing 2.8 to 6.5 kg. INTERVENTIONS: Doppler probes were placed on the endotracheal tube tip (transtracheal Doppler) and directly on the aortic adventitia (extravascular Doppler). A 4-Fr thermodilution catheter was inserted in the pulmonary artery. Stroke volume and cardiac output determinations were recorded at baseline, after a 15-mL/kg volume load and after successive 15-mL/kg blood withdrawals to exsanguination or a systolic blood pressure of < 20 mm Hg. MEASUREMENTS AND MAIN RESULTS: Transtracheal and extravascular Doppler measurements of cardiac output were not significantly different from thermodilution at any physiologic state. These techniques were able to measure stroke volumes and cardiac outputs at the low levels seen in severe hemorrhagic shock. CONCLUSIONS: Transtracheal Doppler and extravascular Doppler measurements of cardiac output compare favorably with thermodilution. These methods effectively followed trends from alterations in intravascular volume, even at very high heart rates and small stroke volumes. Transtracheal Doppler and extravascular Doppler should yield useful information in critically ill neonatal patients, where data regarding stroke volume and cardiac output may be useful in clinical management.

Animals↗

Extravasation rates and complications of intraosseous needles during gravity and pressure infusion.

OBJECTIVE: To compare the extravasation rates and insertion complications under gravity and 300 mm Hg (40 kPa) pressure infusion of threaded (SurFast and Sussmane-Raszynski intraosseous needles, Cook Critical Care, Bloomington, IN); and nonthreaded needles (16-gauge disposable intraosseous needle with 45 degrees trocar Cook Critical Care, Bloomington, IN; Jamshidi bone marrow needle; Baxter Health Care Corp, Valencia, CA). DESIGN: A prospective, randomized study. SETTING: An animal laboratory at a university center. SUBJECTS: Five healthy mix breed piglets, weighing 15 to 15.5 kg. INTERVENTIONS: Piglets were anesthetized and ventilated. Tibial, femoral, and humeral osseous sites were exposed by dissection of overlying tissue. All bleeding points were cauterized and oozing was prevented by sealing with cyanoacrylate. Intraosseous access devices then were inserted one at a time in random order and rated for difficulty of insertion. Normal saline solution was infused under gravity or 300 mm Hg (40 kPa) pressure. Extravasation rates then were calculated from the increase in weight of a gauze sponge wrapped tightly at the base of the needle during infusion. MEASUREMENTS AND MAIN RESULTS: No significant (p > .05) differences in extravasation rates were noted among the different types of needles, either under gravity or pressure infusions. The Sussmane-Raszynski needle was significantly more difficult to insert than the others (rated difficult to insert and control in 16 of 34 attempts). Inadvertent penetration of both cortices occurred with nonthreaded needles only (three of 66 attempts). The SurFast needle provided greatest penetration control and was most resistant to accidental dislodgement. CONCLUSIONS: Under ideal conditions, needle type does not influence extravasation rates. However, difficulty with insertion and penetration of both cortices occur commonly and may lead to extravasation during stressful emergency situations or when performed by unskilled personnel.

Animals↗

Pediatric and adult thoracic trauma: age-related impact on presentation and outcome.

UNLABELLED: To assess the impact of age on presentation and outcome, 2,415 cases involving blunt and penetrating thoracic trauma over an 8-year period were reviewed retrospectively from a single level I trauma center. Of the 2,073 patients alive on arrival, 79 were 12 years of age or less (children), 137 were 13 to 17 years of age (adolescent), 1,742 were 18 to 59 years of age (adults), and 115 were 60 years of age or more (elderly). Chi-square analysis was performed relative to presentation (blunt versus penetrating), need for thoracotomy, and hospital mortality. Although blunt thoracic trauma comprised 64/79 of children (81%) and 90/115 of the elderly (78%), penetrating thoracic trauma was more common for adolescents 79/137 (58%) and adults 1013/1742 (58%) (p < 0.05). There was no significant difference in need for thoracotomy among the four age groups after blunt thoracic trauma. For penetrating trauma, however, there was a significantly higher incidence of thoracotomy in children as compared with the other three age groups (p < 0.05). IN CONCLUSION: (1) Blunt injuries comprised a greater proportion of thoracic trauma in children and the elderly. (2) In this series, children with penetrating thoracic trauma underwent thoracotomy more frequently. (3) Hospital mortality appeared to be increased for the elderly. (4) Analyses of pediatric thoracic trauma must separate children from adolescent age groups.

Adolescent↗

Treatment of critical status asthmaticus in children.

Status asthmaticus is complex in its etiology and pathophysiology and may be associated with significant morbidity and mortality. Although there are many therapeutic options, specific inhaled beta 2-agonists, corticosteroids, and oxygen remain the mainstay of therapy. Several new drugs and some older drugs are being used in management; their exact role in treatment at present, however, relies largely on personal preferences. Innovative methods of providing ventilatory support are also emerging. What is quite clear is the fact that involvement of specialists (pulmonologists and intensivists) early in the course of severe status asthmaticus is needed to ensure optimal management and possibly favorable outcomes.

Adolescent↗