Biomedical subjects

G Michael Davis

Publications and source records attributed to G Michael Davis.

7 recordsLinked to original sources

PubMed2006

Tracheostomy in children.

Indications, timing, and interventions to the airway resulting in tracheostomy are poorly characterised. There are no promulgated standards of care for tracheostomy in children. This paper addresses the issues associated with decision for tracheostomy, the timing of the intervention, the care for the tracheostomy in both the acute and chronic phase and the necessities for care at home. The paper attempts to describe some of the apparent problems associated with tracheostomy and practical techniques for treatment of the inadvertent complications.

Airway Obstruction↗

PubMed2006

'It's okay, it helps me to breathe': the experience of home ventilation from a child's perspective.

There are few studies that focus on children's subjective responses to home ventilation and how this in turn affects their daily lives. This multiple case study explored the experience of home ventilation from the children's perspective. Data were collected from five children through observation and audiotaped interviews. Children expressed their physical and emotional relationship with the ventilator, stating: 'It's okay. It helps me to breathe' - a theme that had a number of distinct dimensions. Other themes included the medicalization of childhood, being a child and hopes for the future. Unlike other study findings to date, the children in this study concluded that the technology was only one small part of their lives. Nurses must ensure that these children have an opportunity to communicate their perspectives, in order to provide care that is clinically effective and child-centered.

Activities of Daily Living↗

PubMed2005

Impulse oscillometry: reference values in children 100 to 150 cm in height and 3 to 10 years of age.

OBJECTIVES: To generate reference equations in North American children to be used for assessing respiratory function through the forced oscillation (Rfo) technique, and to determine the changes in oscillatory resistance, reactance, and resonant frequency (Fres) in relation to age, body height, and weight. DESIGN/SETTING: A prospective cross-sectional study performed on healthy children selected according to strict criteria of American Thoracic Society and European Respiratory Society recommendations. MEASUREMENTS: Triplicate measures were obtained of resistance and reactance at 5, 10, 15, 20, 25, and 35 Hz as well as Fres through the impulse oscillometer (MasterScreen IOS; Jaeger/Toennies; Höchberg, Germany). Two hundred twenty-two white children--normally distributed within the 3- to 10-year age range and 100 to 150 cm in height--were recruited in Montreal, Canada. We used regression analysis to generate multiple predictive equations separately per gender and frequency on age, height, and body weight. RESULTS: Stepwise multiple regression in both natural and logarithmic forms for height, weight, age, and gender showed that standing height was the only significant predictor for all variables. Minimal variability was noted in each subject among the triplicate measurements (p = 0.68 to 0.96). Coherence was > 0.9 at all oscillating frequencies except 5 Hz (< 0.72), with tendencies to lower values in young children. CONCLUSIONS: Resistance and Fres decrease by height, but also by age; and reactance increases. As opposed to our past experience with spirometry in compatible age groups, the Rfo technique was well accepted by preschool children.

Body Height↗

PubMed2004

Planning adenotonsillectomy in children with obstructive sleep apnea: the role of overnight oximetry.

OBJECTIVE: Obstructive sleep apnea (OSA) in children is usually effectively treated by adenotonsillectomy (T&A). However, there may be a waiting list for T&A, and the procedure is associated with an increased risk of postoperative complications in children with OSA. Needed is a simple test that will facilitate logical prioritization of the T&A surgical list and help to predict children who are at highest risk of postoperative complications. The objective of this study was to develop and validate a severity scoring system for overnight oximetry and to evaluate the score as a tool to prioritize the T&A surgical list. METHODS: This study comprised 3 phases. In phase 1, a severity score was developed by review of preoperative overnight oximetry in children who had urgent T&A in 1999-2000. In phase 2, the score was validated retrospectively in 155 children who had polysomnography (PSG) before T&A in 1992-1998. In a phase 3, a 12-month prospective evaluation of a protocol based on the score was conducted. RESULTS: In phase 1, a 4-level severity score was developed on the basis of the number and the depth of desaturation events (normal to severely abnormal, categories 1-4). In phase 2, the McGill oximetry score correlated with severity of OSA by PSG criteria. In phase 3, a clinical management protocol was developed based on the score. Of 230 children tested, 179 (78%) had a normal/inconclusive oximetry (category 1) and went on to have PSG. Those with a positive oximetry (categories 2-4; 22%) had no additional sleep studies before T&A. Timing of T&A was based on oximetry score, leading to a significant reduction in waiting time for surgery for those with higher oximetry scores. Postoperative respiratory complications were more common with increasing oximetry score. CONCLUSIONS: Overnight pulse oximetry can be used to estimate the severity of OSA, to shorten the diagnostic and treatment process for those with more severe disease, and to aid clinicians in prioritization of T&A and planning perioperative care.

Adenoidectomy↗

PubMed2003

Validity of esophageal pressure measurements with positive end-expiratory pressure in preterm infants.

Previous research suggested that esophageal pressure changes (DeltaP(es)) may not reflect pleural pressure changes (DeltaP(pl)) in the presence of positive end-expiratory pressure (PEEP), making assessments of dynamic lung mechanics invalid in these circumstances. To test this hypothesis, we measured DeltaP(es) using a water-filled catheter in 18 preterm infants with lung disease (9 intubated), and adjusted the catheter position to achieve a valid occlusion test. End-expiratory occlusions were then carried out at PEEP (cm H(2)O) of 0, 4, and 8, and plots of DeltaP(es) against DeltaP(ao) during airway occlusion were examined to derive the ratio DeltaP(es)/DeltaP(ao) and the r value (as a measure of linearity). There was no significant change in DeltaP(es)/DeltaP(ao), which remained close to 1.0 as PEEP was increased from 0 to 8 cm H(2)O, and r also remained close to unity, indicating no appreciable hysteresis or alinearity of the plots. Our results show that DeltaP(es), when measured with an appropriately placed water-filled catheter, continues to reflect DeltaP(pl) accurately when lung volume is raised by applying PEEP up to 8 cm H(2)O.

Catheterization↗

PubMedDate not supplied

The Asthma Quiz for Kidz: a validated tool to appreciate the level of asthma control in children.

BACKGROUND: There is an urgent need to bridge the large gap between optimal and observed asthma control among Canadian children. OBJECTIVES: To adapt the criteria of asthma control proposed in the 1999 Asthma Consensus Statement for children and validate the proposed cut-offs in children with asthma. METHODS: Six clinical criteria of asthma control were phrased as questions and response options, and pretested for clarity. A cross-sectional study was conducted in children one to 17 years of age presenting to the hospital's asthma clinics. Children nine years of age or older and their parents were asked to complete The Asthma Quiz for Kidz separately, and then together, before the medical visit. Parents of younger children completed the questionnaire with their child. Physicians were not informed of the results of the quiz. RESULTS: The mean age of the 343 participants was 8.0+/-4.4 (SD) years with a mean baseline forced expiratory volume in 1 s of 96+/-15% of predicted values. Asthma severity was rated as mild (67%), moderate (29%) or severe (4%). Overall, 57% of subjects endorsed at least two of the six criteria of poor control. The median (interquartile range) Asthma Quiz score was significantly higher when the physician's assessment of asthma control was poor than when the physician's assessment of asthma control was good (3 [1, 5] versus 1 [0, 2], P<0.001), but it did not correlate with the spirometry. A score of at least 2 out of 6 had 73% sensitivity and 59% specificity for identifying poor control. INTERPRETATION: The Asthma Quiz score provides complementary information to, but does not replace, lung function testing. A score of 2 or more out of 6 suggests poor asthma control and should prompt patients to consult their physician for reassessment.

Adolescent↗

PubMedDate not supplied

Minimal exhaled nitric oxide production in the lower respiratory tract of healthy children aged 2 to 7 years.

BACKGROUND: Exhaled nitric oxide (eNO) is elevated in inflammatory airway conditions, e.g. asthma. We measured eNO levels in normal preschool children for whom there is little data available and in whom the prevalence of asthma is high. SUBJECTS AND METHODS: Fifty children, 2-7 years old, undergoing elective surgery, excluding airway procedures, were recruited. Children with known respiratory disease or acute viral infections were excluded. Gas for eNO measurement was collected in a non-diffusion bag via 1) the mask after inhalation induction of anesthesia, 2) endotreacheal tube (ETT) or laryngeal mask airway (LMA), and 3) during emergence. Measurement was off-line by chemiluminescent analyzer. RESULTS: Mean eNO level by mask was 10.23 ppb (mean value+/-SD of 8.8-11.1 ppb) after induction and 8.35 ppb (mean value+/-SD of 5.9-10.8 ppb) on emergence. Mean eNO for the intubated group (n=25) was 0.75 ppb (mean value+/-SD of 0.4-1 ppb) (P<0.0001 vs mask); mean eNO for the LMA group (n=25) was 2.6 ppb (mean value+/-SD of 2-3.2 ppb), which differed from the mask (P<0.0001), and from ETT values (P<0.0001). CONCLUSIONS: Most eNO is produced by the upper airway in healthy pre-school children. The lower airway constitutive eNO production is very low. The LMA does not completely isolate the upper airway and current mask collection techniques allow significant contamination of samples by sino-nasal eNO production in young children.

Child↗