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Biomedical subjects

Desmond Bohn

Publications and source records attributed to Desmond Bohn.

30 records · Page 2Linked to original sources
PubMed2003

The influence of perioperative factors on outcomes in children aged less than 18 months after repair of tetralogy of Fallot.

OBJECTIVES: To determine the impact of age at repair in patients with tetralogy of Fallot on early postoperative morbidity. METHODS: All patients less than 19 months of age (median age, 8 months; range, 36 days-18.5 months) who underwent complete repair of tetralogy of Fallot between January 1997 and December 1999 were reviewed. Data were analyzed on the preoperative clinical and anatomical characteristics, operative procedure and postoperative course in the intensive care unit. Independent factors associated with intensive care unit stay were sought using Cox's proportionate hazard modeling. In addition, independent factors associated with an intensive care unit stay of more than 2 days were sought in multiple logistic regression analysis. RESULTS: Seventy-eight patients underwent surgical repair; 3 had (4%) had a previous systemic to pulmonary arterial shunt. There was no operative mortality. One late death occurred. The median intensive care unit length of stay and mechanical ventilation time were 2 days (range, 1-14) and 16.2 hours (range, 0-267), respectively. Age less than 3 months was associated with increased use of vasoactive drugs, higher postoperative fluid requirement, and a higher incidence of organ dysfunction but no patient required renal replacement therapy. The duration of ventilator support and the intensive care unit length of stay were also longer in this age group. CONCLUSIONS: Primary repair at an early age has excellent short-term outcome. Patients less than 3 months of age have an increased but transient intensive care unit morbidity.

Age Factors↗
PubMed2003

Discrepancies between ordered and delivered concentrations of opiate infusions in critical care.

OBJECTIVES: We sought to test the assumption that the measured concentrations of medication infusions are within pharmaceutical standards (+/-10% of intended concentrations) and whether, at the time the infusion was mixed, the professional background of persons preparing the infusion or the unit for which the infusion was prepared were related to the observed variation. DESIGN, SETTING, AND PARTICIPANTS: This prospective, observational study was conducted in the neonatal and pediatric intensive care units of a university-affiliated tertiary pediatric center. Morphine infusions prepared for clinical use were randomly sampled over a 7-month period. Those with no error between labeled and ordered concentration were further analyzed. High-performance liquid chromatography was used to determine the concentration of morphine infusions. The primary outcome was a difference of >10% between ordered and measured concentrations. MEASUREMENTS AND MAIN RESULTS: The measured concentration of 65% of the 232 infusions was >10% different from the ordered concentration (95% confidence interval, 58-71%). The concentrations of 6% of infusions represented two-fold errors (95% confidence interval, 3-9%). The difference was normally distributed around zero, suggesting a cumulative effect of random errors, rather than a systematic bias. The time that the infusion was prepared, the professional background of the persons preparing the infusion, and the unit for which the infusion was mixed were not significant predictors of discrepancy (p =.74, analysis of variance). CONCLUSIONS: The concentration of two thirds of infusions prepared for clinical use was outside accepted industry standards. These findings are likely to be broadly representative of intravenous drug administration in hospitalized children and pediatric pharmacokinetic studies. Further study of the causes and clinical impact is required.

Critical Care↗
PubMed2003

Inhaled nitric oxide for acute hypoxic respiratory failure in children and adults: a meta-analysis.

We systematically reviewed randomized controlled trials examining inhaled nitric oxide (INO) for the treatment of acute respiratory distress syndrome or acute lung injury in children and adults. Qualitative assessments of identified trials were made, and metaanalyses were performed according to Cochrane methodology. Five randomized controlled trials (n = 535) met entry criteria. One study demonstrated significant improvement in oxygenation in the first 4 days of treatment, with no difference after this. There was no difference in ventilator-free days between treatment and placebo groups, and no specific dose of INO was more advantageous than any other. INO had no effect on mortality in trials without crossover of treatment failures to open-label INO (relative risk, 0.98; 95% confidence interval, 0.66-1.44). Other clinical indicators of effectiveness, such as duration of hospital and intensive care stay, were inconsistently reported. Lack of data prevented assessment of all outcomes. If further trials assessing INO in acute respiratory distress syndrome or acute lung injury are to proceed, they should be stratified for primary etiology, incorporate other modalities that may affect outcome, and evaluate clinically relevant outcomes before any benefit of INO can be excluded.

Acute Disease↗
PubMed2002

Clinical approach to disorders of salt and water balance. Emphasis on integrative physiology.

Our purpose was to illustrate the utility of an approach that begins with simple principles of physiology to patients who have a disturbance in salt and water balance (Table 1). At times, the physiology is restricted to the kidney and body fluid compartments. In these settings, the goals of therapy are defined by calculating a tonicity balance--electrolyte-free water balances simply do not provide the needed information [3]. At other times, performing balances of other solutes such as urea reveal that another critically important problem is present (tissue catabolism). Thus the physiologic analysis becomes more integrative, extending beyond renal issues. Goals for therapy become clearer once the integrative physiology is known. More modern contributions from molecular studies permit a revised interpretation of the physiology. An example presented was the possible role of gentamicin-like drugs as a cause of high output renal failure that is basically a persistent loop diuretic-like effect. In the patient presenting with hyponatremia, the first step is to determine if the time course is less than 48-hours because emergency therapy is different in this setting. With acute hyponatremia, the objective is to diminish brain cell swelling especially if even mild symptoms are present. In contrast, the objective in the patient with chronic hyponatremia is to prevent ODS. An even slower rate of rise of the PNa is required in patients who are malnourished and/or K+ depleted.

Acute Disease↗
PubMed2002

Fetal pulmonary artery diameters and their association with lung hypoplasia and postnatal outcome in congenital diaphragmatic hernia.

OBJECTIVE: We hypothesized that fetal branch pulmonary artery (PA) diameters indirectly reflect lung mass and are associated with postnatal outcome in cases of isolated congenital diaphragmatic hernia (CDH). STUDY DESIGN: We retrospectively reviewed echocardiograms of fetuses with CDH, measuring branch PA diameters and other echocardiographic parameters. Antenatal parameters were correlated with postmortem lung weights in 5 fetuses after pregnancy termination. Fetal echocardiographic measures were correlated with outcome variables in 29 live-born infants with CDH to identify antenatal indices associated with postnatal death and respiratory morbidity. RESULTS: Antenatal branch PA size correlated with postmortem lung weights from 5 terminated fetuses (r = 0.87). In 26 cases of left CDH in which the fetus continued to term, the ipsilateral branch PA diameter was significantly smaller than the contralateral branch PA diameter at presentation (P <.001). In these fetuses, a larger contralateral PA diameter was associated with worse postnatal survival (P =.049). Among survivors with left CDH, the main PA z score and the discrepancy between right and left PA diameters correlated positively with duration of supplemental oxygen requirement (P =.019 and P =.022, respectively) and ventilation (P =.036 and P =.012, respectively). Serial antenatal studies in 8 of 10 cases revealed progressive ipsilateral PA hypoplasia. CONCLUSION: Antenatal branch PA size correlates with postmortem lung weight. A larger contralateral PA, and significant branch PA discrepancy and larger main PA diameter, best correlate with postnatal death and respiratory morbidity, respectively. Progressive ipsilateral PA hypoplasia suggests progressive in utero lung hypoplasia in cases of CDH.

Abortion, Induced↗
PubMed2002

Cerebral salt wasting: truths, fallacies, theories, and challenges.

BACKGROUND: The reported prevalence of cerebral salt wasting has increased in the past three decades. A cerebral lesion and a large natriuresis without a known stimulus to excrete so much sodium (Na ) constitute its essential two elements. OBJECTIVES: To review the topic of cerebral salt wasting. There is a diagnostic problem because it is difficult to confirm that a stimulus for the renal excretion of Na is absent. DESIGN: Review article. INTERVENTION: None. MAIN RESULTS: Three fallacies concerning cerebral salt wasting are stressed: first, cerebral salt wasting is a common disorder; second, hyponatremia should be one of its diagnostic features; and third, most patients have a negative balance for Na when the diagnosis of cerebral salt wasting is made. Three causes for the large natriuresis were considered: first, a severe degree of extracellular fluid volume expansion could down-regulate transporters involved in renal Na resorption; second, an adrenergic surge could cause a pressure natriuresis; and third, natriuretic agents might become more potent when the effective extracellular fluid volume is high. CONCLUSIONS: Cerebral salt wasting is probably much less common than the literature suggests. With optimal treatment in the intensive care unit, hyponatremia should not develop.

Brain Diseases↗
PubMed2002

Diabetic ketoacidosis and cerebral edema.

Cerebral edema is the leading cause of death in children presenting in diabetic ketoacidosis and occurs in 0.2 to 1% of cases. The osmolar gradient caused by the high blood glucose results in water shift from the intracelluar fluid (ICF) to the extracellular fluid (ECF) space and contraction of cell volume. Correction with insulin and intravenous fluids can result in a rapid reduction in effective osmolarity, reversal of the fluid shift and the development of cerebral edema. The goals for treatment should be a combination of intravenous fluid and insulin that results in a gradual reduction of the effective osmolarity over a 36- to 48-hour period, thereby avoiding rapid expansion of the ICF compartment and brain swelling.

Animals↗
PubMed2002

High-frequency oscillation in children after Fontan operation.

OBJECTIVE: The increase in intrathoracic pressure produced by positive-pressure ventilation has been shown to have an adverse effect on pulmonary blood flow after Fontan operations. OBJECTIVE: The main objective was to compare the hemodynamic effect of high-frequency oscillation ventilation (HFOV) with intermittent positive-pressure ventilation (IPPV) in children after Fontan operations. DESIGN: Prospective study. SETTING: Department of pediatric critical care in a tertiary care, university-based children's hospital. PATIENTS: Five children (age, 2.3 +/- 0.3 yrs) in the early period after Fontan operations. INTERVENTION: After a short period of stabilization after surgery using conventional IPPV, baseline data were collected and patients were converted to HFOV. After a short period of stabilization using HFOV, a second series of measurements were performed and patients were reconnected to IPPV, after which a third series of measurements were made. Paco(2) and pH were kept unchanged throughout the study. MEASUREMENTS AND MAIN RESULTS: Hemodynamic and respiratory variables were obtained at each time point (IPPV1, HFOV, and IPPV2). The mean cardiac index at baseline (IPPV1) was 3.1 +/- 1.1 L/min/m(2); during HFOV, it was 3.2 +/- 1.2 L/min/m(2) (p =.46); and during IPPV2, it was 3.1 +/- 1.1 L/min/m(2). The mean pulmonary vascular resistance values using IPPV1, HFOV, and IPPV2 were 3.0 +/- 1.1, 2.7 +/- 1.3 (p =.21), and 2.6 +/- 1.1 Woods units/m(2), respectively. CONCLUSION: HFOV had no effect on the cardiac output or the pulmonary vascular resistance in a small group of stable patients after Fontan operations.

Journal Article↗
PubMed2002

Diagnosis and management of pediatric myocarditis.

Myocarditis is an insidious inflammatory disorder of the myocardium. As a clinical entity, it has been recognized for two centuries, but it defies traditional diagnostic tests. A greater understanding of the immune response underlying the pathobiology of the disorder can lead to a more rational therapeutic approach. The presentation, course and therapeutic options appear to be different in the pediatric compared with the adult population. An understanding of the difference between fulminant and acute progressive myocarditis has led to successful treatment strategies. A variety of new therapies are available, including antiviral agents, immunosuppression, and modulation of the biological response to inflammation. The specific question for patients with myocarditis is whether regimens designed to reduce or eliminate inflammation can provide clinical benefits compared with conventional heart failure therapy. This review highlights pathological mechanisms, modalities of diagnosis, and novel therapies which may improve outcomes.

Child↗