Search PubMed⌕ Search

Biomedical subjects

G B Mallory

Publications and source records attributed to G B Mallory.

46 records · Page 3Linked to original sources
PubMed1991

The ventilator-dependent child: issues in diagnosis and management.

Infants, children, and adolescents with chronic respiratory failure are surviving in increasing numbers and, thereby, producing a significant population of ventilator-dependent pediatric patients. Chronic respiratory failure can occur as a complication of a wide variety of disease states; in pathophysiologic terms, it generally results from either decreased central nervous system output or inadequate force generated by the respiratory pump. Its laboratory hallmark is hypercapnia with or without hypoxemia. Stabilization of the patient with mechanical ventilatory support may permit long-term survival. Management of the ventilator-dependent pediatric patient is a complex task that must begin with an accurate prognostication of each patient's survival and quality of life. Once a decision is made concerning the practicality and appropriateness of long-term ventilatory support, informed choices must be made with respect to need for an artificial airway, mode of ventilation, and location of care. Many younger patients, especially those with intrinsic lung disease (like bronchopulmonary dysplasia), may require a hospital setting for long-term care, whereas others with neuromuscular or central disorders may benefit from being discharged to home. The patient's family must be thoroughly educated in the child's care, and they must be involved in decision-making. A multidisciplinary team of physicians, therapists, nurses, and other professionals is required to deliver optimal care. Outcome is good for most patients who are carefully selected.

Child↗
PubMed1990

Enhanced hepatic drug clearance in patients with cystic fibrosis.

To examine whether hepatic drug metabolism is altered in patients with cystic fibrosis (CF), we evaluated the pharmacokinetics of three model pharmacologic substrates (antipyrine, a marker of hepatic oxidative metabolism; lorazepam, a marker of hepatic glucuronosyltransferase activity; and indocyanine green (ICG), a marker of hepatic blood flow and biliary secretion) in 14 patients with CF (14.6 to 29.2 years of age) and in 12 children and adolescents with cancer (7.2 to 19.4 years of age), which was treated with only surgery and radiation. Each study subject received a single intravenous dose of the combined model substrates (0.03 mg/kg lorazepam, 10 mg/kg antipyrine, and 0.5 mg/kg ICG) for 5 minutes, followed by repeated blood sampling (n = 10) during a 24-hour postinfusion period. Patients with CF had a significantly greater plasma clearance of lorazepam (56.5 +/- 5.2 vs 25.9 +/- 1.9 ml/min/m2) and ICG (892.5 +/- 176.4 vs 256.5 +/- 41.7 ml/min/m2) but not of antipyrine (27.2 +/- 3.8 vs 20.7 +/- 2.0 ml/min/m2) in comparison with control subjects. The apparent steady-state volume of distribution for lorazepam, ICG, and antipyrine was significantly higher in the patients with CF (2.0-, 3.1-, and 1.4-fold, respectively) than in control subjects. Clearance of the model substrates did not correlate with standard biochemical markers of hepatic function. Similarly, no significant relationships were observed between the clearance or steady-state volume of distribution of the compounds and the National Institutes of Health prognostic scores for the patients with CF. These data demonstrate that the plasma clearance of lorazepam and ICG is increased in patients with CF and suggest that hepatic glucuronosyltransferase activity and biliary secretory capacity are enhanced in this disease.

Adolescent↗
PubMed1989

Bronchial reactivity in infants in acute respiratory failure with viral bronchiolitis.

Airway reactivity and the effects of bronchodilators in infants are controversial. We studied the response to bronchodilator treatment in 14 mechanically ventilated infants (mean age, 2.74 months; range, 0.6-5.9) in respiratory failure caused by respiratory syncytial virus (RSV)-associated bronchiolitis. Sixteen infants without lung disease, undergoing elective surgery, provided normal values. Maximum expiratory deflation flow-volume (DFV) curves were produced by manual inflation of the lungs with an anesthesia bag to a predetermined static airway pressure followed by rapid deflation with a negative airway pressure before and after administration of bronchodilator. At baseline, the bronchiolitis group had a forced vital capacity (FVC) of 34.5 +/- 3.6 ml/kg compared with 41.8 +/- 1.5 ml/kg in the normal group; maximum expiratory flow rate at 25% of FVC (MEF25) was 10.2 +/- 2.0 ml/kg/s compared with 27.3 +/- 2.0 ml/kg/s in the normal group. The clinical and radiologic impression was severe lower airway obstruction and air trapping. After administration of bronchodilator, FVC did not increase significantly, but MEF25isov increased by over 30% in 13 of 14 infants. Mean MEF25 increased by 148 +/- 43.2% to 21.7 +/- 3.9 ml/kg/s (P less than 0.02). These findings indicate that during the acute phase of severe RSV-positive bronchiolitis most infants have airway reactivity that responds positively to bronchodilator treatment.

Acute Disease↗
PubMed1989

Significance of opacification of the maxillary and ethmoid sinuses in infants.

To evaluate the incidence and significance of radiographic sinus opacification in infants, we performed computed tomography (CT) of the maxillary and ethmoid sinuses in conjunction with routine cranial CT in 100 infants from birth to 12 months of age. CT was performed for indications other than sinusitis. Prospective concurrent clinical history was obtained and physical examination of the upper respiratory tract was performed. Of 100 infants, 16 had hypoplasia of the maxillary sinuses; 81% (13/16) of these were less than 2 months of age. The antra showed progressive increase in size during the first year of life. Of the 100 infants, 70 had CT sinus opacification, including 67% of those without historical or physical evidence of upper respiratory tract infection. There was a positive correlation of CT findings between the maxillary and ethmoid sinuses in 80% of the infants older than 2 months of age but in only 49% of the younger infants. Radiographic sinus opacification in infants is of uncertain significance and is not diagnostic of upper respiratory tract infection, much less of sinusitis.

Age Factors↗
PubMed1989

Sleep-associated breathing disorders in morbidly obese children and adolescents.

Forty-one children and adolescents with a history of breathing difficulty during sleep and morbid obesity, defined as greater than 150% ideal body weight, underwent polysomnography to determine the incidence of sleep-associated breathing disorders. Seventeen patients also performed pulmonary function testing. The mean patient age was 10.3 +/- 4.4 (SD) years, and mean percent of ideal body weight was 208 +/- 42.2. A sleep history questionnaire showed that all patients snored, but frank apnea was reported in only 32%. The pulmonary function tests showed 18% (3/17) with a restrictive defect and 47% (8/17) with obstructive changes. The polysomnograms in 37% (15/41) of the patients were abnormal because of apnea, hypopnea, excessive arousals, or abnormalities in gas exchange. Multiple regression analysis demonstrated no significant association between weight, age, or gender and any physiologic measure on the polysomnogram. Most of the abnormal polysomnograms (13/15) were mildly abnormal, but two showed sufficiently severe abnormalities to require clinical intervention. We conclude that children and adolescents with morbid obesity are at risk for sleep-associated breathing disorders; their polysomnographic abnormalities are usually mild but rarely may be severe enough to require clinical intervention.

Adolescent↗
PubMed1989

Effectiveness of open-circuit and oxyhood delivery of helium-oxygen.

The combination of helium with oxygen is less dense than air and as such has been beneficial to patients with airflow obstruction within the large airways. The purpose of this study was to evaluate the effectiveness of delivering He-O2 by open-circuit systems by measuring DD50 in five adult volunteers. The mean (+/- SD) DD50 with a nonrebreathing mask was 1.32 +/- 0.89, with a simple mask was 1.21 +/- 0.87, and with a nasal cannula was 1.00 +/- 0.13; the DD50 with the nonrebreathing mask and the simple mask was statistically greater than with the cannula (p less than 0.05). Two infant oxygen hoods were assessed by measuring the nitrogen concentration at different locations in the hoods. The N2 concentration increased progressively from top to bottom, indicating that the helium was concentrated at the top. We conclude that the nonrebreathing mask and simple masks are probably satisfactory He-O2 delivery systems, that the infant oxyhood may be suboptimal, and that the nasal cannula is ineffective.

Adult↗
PubMedDate not supplied

Depilation in a 6-month-Old with hypertrichosis: A case report.

Hypertrichosis in the pediatric age group can be troubling to both patients and parents. There is no well-established method for managing this problem in young children. We describe the successful use of a cream depilatory agent for removal of excess hair from the face and body of a 6-month-old girl. Excellent cosmetic results were obtained. The risks and benefits of the use of depilatory cream in young patients are analyzed. Other options for hair removal in children are also reviewed.

Face↗
PubMedDate not supplied

Tidal flow measurement in the decision to decannulate the pediatric patient.

Measurements of peak inspiratory flow obtained through the tracheostomy cannula (MIFT) during tidal breathing were compared to peak inspiratory flow measurements obtained through the mouth (MIFM) in 40 children to assess physiologic readiness to decannulate the tracheostomized pediatric patient. Ratio of peak flow MIFM/MIFT was 1.40 for 34 successfully decannulated children compared to 0.83 for 22 unsuccessful attempts (p less than 0.01). Tidal flow measurements are highly predictive (84%) in identifying children who are unlikely to be ready for decannulation. A schema is proposed to utilize tidal flow measurements as the first step in the decannulation process.

Adolescent↗