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Biomedical subjects

N Kissoon

Publications and source records attributed to N Kissoon.

At least 19 recordsLinked to original sources
PubMed2001

Low exhaled nitric oxide and a polymorphism in the NOS I gene is associated with acute chest syndrome.

Abnormalities of nitric oxide metabolism have been implicated in the pathogenesis of acute chest syndrome in subjects with sickle cell anemia. It is not known whether exhaled nitric oxide levels (FE(NO)) are abnormal in children with a history of the acute chest syndrome (ACS). We compared FE(NO), plasma nitric oxide metabolites (NO(x)), serum arginine and citrulline levels, and the number of AAT repeats in intron 20 of NOS I in subjects with sickle cell disease (SCD) and a history of at least one episode of ACS (ACS(+), n = 13), subjects with SCD and no prior history of ACS (ACS(-), n = 7), and healthy children (HC, n = 6). Mean +/- SD FE(NO) (ppb) was lower in ACS(+) than in ACS(-) and HC: (10.4 +/- 4.3 versus 23.4 +/- 6.1 p = 0.002] and 30.4 +/- 15.8 [p = 0.0001], respectively). Plasma NO(x) (microM) were similar in all three groups (37.3 +/- 19.4, 33.0 +/- 13.2, 44.7 +/- 7.8, respectively). Arginine and citrulline levels (microM) did not differ between ACS(+) and ACS(-) groups. Spirometric data revealed a mildly diminished FEV(1) and FVC in ACS(+) that was statistically different from HC but not ACS(-): (FEV(1) as % of predicted for ACS(+), ACS(-), and HC; 83 +/- 17 versus 87 +/- 16 versus 102 +/- 16, respectively, p < 0.05 between ACS(+) and HC). The level of FE(NO) was significantly associated with the sum of AAT repeats in intron 20 of NOS I gene alleles. The correlation coefficient (r) was 0.62 (p < 0.005). We conclude that FE(NO) levels are significantly reduced in subjects who have a history of ACS and that the FE(NO) levels are significantly correlated with the number of NOS I AAT repeats. FE(NO) is a sensitive marker and may be a predictor of ACS prone children.

Acute Disease↗
PubMed2001

Child with absent vital signs.

The outcome of cardiopulmonary resuscitation in the child with absent vital signs is dismal. Best outcomes therefore should rely on early recognition and aggressive management of critical illness to interrupt deterioration to cardiorespiratory arrest. Moreover, resuscitation entails a spectrum of care starting with cardiopulmonary resuscitation at the site of injury through critical care and post resuscitation rehabilitation. The resources required to provide this level of care is not available in many parts of the world. Therefore, resuscitation skills should be taught to caregivers at a level which is congruent to their role in the continuum of care and the use of aggressive resuscitation needs to be tailored based on geography, risk to medical personnel, preservation of resources, transplantation issues and expected outcomes. In some cases, the most prudent decision may be not to attempt resuscitation of the child with absent vital signs.

Advanced Cardiac Life Support↗
PubMed2001

Noninvasive monitoring in the pediatric intensive care unit.

The best ICU monitors are physicians and nurses, who integrate all of the physiologic parameters of patients with the known pathophysiology of the disease process. Over-reliance on raw electronic data, with their inherent errors, jeopardizes the safe and efficient care of patients. Data must be interpreted in the context of the history, repetitive physical examinations, response to therapy, and a background of experience. New modalities and the application of artificial intelligence may facilitate the interpretation of data, but the role of the bedside medical practitioner remains as the heart of pediatric critical care.

Blood Gas Monitoring, Transcutaneous↗
PubMed2001

Plastic bottles as spacers for a pressurized metered-dose inhaler: in vitro characteristics.

Homemade spacer devices are commonly used by children with asthma to improve aerosol deposition from pressurized metered dose inhalers (pMDI); however, the efficacy and efficiency of these devices are not fully characterized. We determined the quality of fine particle fraction (< 4.7 microns) and ultrafine particle fraction (< 3.3 microns) of three bottles (from 280 ml to 500 ml) commonly used as spacers in Trinidad and Tobago and compared their performance to the commercially available valved holding chamber (OpT) and pMDI. These data were obtained in vitro using a cascade impactor. All 3 bottles and the OpT were similar (p > 0.05) in reducing the amount of albuterol emitted as large particles (> 4.7 microns) to less than 10 micrograms. The different sized bottles (from 280 ml to 500 ml) produced identical quantities of albuterol in the fine particle and ultrafine particle ranges (p > 0.05). All of the sample bottle spacers emitted a higher amount (p < 0.002) of fine and ultrafine particles than the OpT and pMDI alone. The OpT resulted in a significantly higher fraction of fine particles (p < 0.05) and a greater quantity of drug (p < 0.05) in the ultrafine range as compared to the MDI only. The sizes of particles obtained from the bottle spacers are those that have a high probability of reaching the lower airway; however, the clinical relevance of these findings remains to be determined.

Asthma↗
PubMed2000

Exhaled nitric oxide as an indicator of severity of asthmatic inflammation.

Traditional assessment of severity of asthma relies on an evaluation of signs and symptoms and pulmonary function tests. These pulmonary function tests, such as peak expiratory flow rates, forced vital capacity, and forced expiratory flow rates, are indirect measures of airway caliber only, and not inflammation. Since asthma is an inflammatory disease, a measure of the degree of inflammation would be helpful in quantitating severity and titrating of anti-inflammatory therapy. A noninvasive method for measuring pulmonary inflammation would therefore be helpful to assist the emergency physician in initial treatment and assist in titration of anti-inflammatory therapy during repeat visits. Exhaled nitric oxide (NO) assays are convenient and practical and may fulfill this role. In this review, we discuss the role of NO in asthmatic inflammation and the role that exhaled NO values may play in the emergency management of asthma.

Asthma↗
PubMed2000

FE(NO): relationship to exhalation rates and online versus bag collection in healthy adolescents.

Measurement of exhaled nitric oxide (FE(NO)) is a noninvasive and practical method for assessing airway inflammation. We conducted this investigation to determine the most appropriate flow rate for FE(NO) measurement and to obtain normal values for FE(NO). We determined which expiratory flow was easy to sustain, generated reproducible values, and provided good correlation between offline and online measurements. Thirty-two healthy subjects (15- 18 yr old) underwent spirometry and FE(NO) measurements, using a chemiluminescent NO analyzer at expiratory flow rates of 46, 31, 23, 15, 10, 7, 5, and 4 ml/s. The major findings were as follows: (1) FE(NO) increased as flow rates decreased, with strong correlation between FE(NO) values and flow rates at the four highest flows (0. 85- 0.93, p < 0.001); (2) there were no significant differences and good agreement between offline bag and online FE(NO) values for the four highest flows (p < 0.09-0.83); (3) online FE(NO) values increased with age 15-17 yr at all flow rates, but decreased at age 18 yr; and (4) using multiple regression, significant predictors of FE(NO) were flow, body surface area, age, and FEF(25-75). On the basis of these results, we provide FE(NO) values for healthy adolescents and propose that the ideal flow rate for children is between 30 and 50 ml/s.

Adolescent↗
PubMed2000

Measurement of lung inflammation in asthmatics. Reason for optimism.

It is recognized that bronchial asthma is an inflammatory disease. However, aggressive anti-inflammatory therapy is not guided by the degree of lung inflammation. This is of particular concern in children in whom over-aggressive therapy with corticosteroid may lead to growth retardation. Analysis of breath exhaled nitric oxide levels may be an indirect measurement of lung inflammation. Since exhaled nitric oxide levels and inflammation decrease after steroid therapy, measurement of exhaled nitric oxide levels may provide a rationale for optimization of steroid therapy and possible reduction of side effects. Measurement of exhaled nitric oxide levels is not available for routine use but may be so in the near future. This will likely herald a new dawn in the management of asthma, a disease with increasing frequency, mortality and morbidity.

Anti-Inflammatory Agents↗
PubMed1999

Exhaled nitric oxide measurements in childhood asthma: techniques and interpretation.

In this review, we outline the role of nitric oxide in airway inflammation in children with asthma. We also discuss the various methods reported for measuring exhaled nitric oxide and provide some insight as to the pros and cons and pitfalls of these techniques. Guidelines for measurements of exhaled nitric oxide based on our experience are provided, as well as suggestions for the use of this technique as a new "airway inflammation test."

Asthma↗
PubMed1999

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↗
PubMed1999

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↗
PubMed1999

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↗