At the crossroads--neonatal detection of developmental dysplasia of the hip.
Explore the source record for details and available documents.
Female↗
Biomedical subjects
C A Dezateux
Publications and source records attributed to C A Dezateux.
Comparison of single-breath and plethysmographic measurements of resistance in infancy.
Single-breath technique (SBT) measurements of total respiratory resistance (Rrs) were compared with plethysmographic measurements of airway resistance (Raw) in healthy infants < or = 13 wk of age (Group 1; n = 49) and > 13 wk of age (Group 2; n = 37) and in infants > 13 wk of age with prior wheeze (Group 3; n = 49). A significantly higher percentage of Rrs (19%) than of Raw (2%) measurements were technically unsatisfactory, alinearity of the flow-volume curve accounting for 54% of Rrs failures. Although both Rrs and Raw were significantly higher in Group 3 infants, between-subject variability was wide in all groups. Rrs was significantly higher than initial expiratory (IE) Raw in all groups. Mean difference Rrs-IE Raw (95% CI) values were 1.98 (1.51, 2.48), 1.29 (0.96, 1.62), and 1.97 (1.56, 2.38) kPa.L-1.s for Groups 1, 2, and 3, respectively. Significant but smaller differences were seen for end-expiratory (EE) Raw in Groups 1 and 2 but not in Group 3. Mean difference Rrs-EE Raw (95% CI) values were 0.68 (0.11, 1.26), 0.55 (0.19, 0.92), and 0.31 (-0.06, 0.69) kPa.L-1.s for Groups 1, 2, and 3, respectively. Despite wide between-subject variability in Rrs and a relatively high failure rate, the SBT is simple to use, and it may be applicable to epidemiologic studies. However, clinical applications in individual infants may be limited by failure to detect the dynamic changes in resistance throughout the breath evident from plethysmographic studies.
Airway Resistance↗
The relationship between tPTEF:tE and specific airway conductance in infancy.
This study examines the association between the time taken to achieve peak tidal expiratory flow as a proportion of total expiratory time (tPTEF:tE) and specific airways conductance (SGaw) in healthy infants and those with prior physician diagnosed, associated, lower respiratory illness with wheezing (prior LRI) during the first year of life. We compared tPTEF:tE and SGaw, the latter estimated during both initial inspiration (ll) and end-expiration (EE), in 168 infants (94 males), measured on 220 occasions. Mean (range) tPTEF:tE was 0.321 (0.150-0.522) in 73 healthy infants aged less than 3 months (mean, 7.8 weeks), in whom mean (range) EE SGaw and plethysmographic thoracic gas volume at functional residual capacity (FRCpleth) were 2.47 s-1 kPa-1 (0.6-5.8) and 141 mL (87-204), respectively. Both tPTEF:tE and EE SGaw were significantly lower in older infants with prior LRI (n = 79; mean age, 50.0 weeks) compared to a similarly aged group of healthy infants (n = 68; mean age, 48.5 weeks), the mean difference [95% confidence intervals (CI)] being -0.039 (-0.013, -0.064) and -0.48 s-1 kPa-1 (-0.24, -0.72), respectively. A significant but weak association between tPTEF:tE and EE SGaw was found among infants above 3 months of age, irrespective of prior wheezing status. However, this relationship was not significant in healthy younger infants, in whom a significant but weak association with FRCpleth was found. Further work is needed to elucidate the factors influencing tidal expiratory flow patterns in infancy.
Age Factors↗
Hering-Breuer reflex and respiratory system compliance in the first year of life: a longitudinal study.
The airway occlusion technique for measuring passive respiratory mechanics in infants relies on an ability to evoke the Hering-Breuer lung inflation reflex (HBR). However, there is conflicting evidence regarding the persistence of the HBR beyond the early newborn period. This study was designed to assess maturational changes in HBR activity and passive total respiratory system compliance (Crs) in healthy infants during the 1st yr of life. The strength of the HBR was assessed from the relative change in expiratory time (TE) after brief end-inspiratory airway occlusions compared with resting TE during spontaneous breathing. Crs was measured using the multiple-occlusion technique. Paired measurements of HBR activity and Crs were obtained during sedated sleep in 30 infants at 4-8 wk and at 1 yr of age. Significant HBR activity during tidal breathing persisted throughout the 1st yr of life, with TE increasing during occlusion by at least 26% in every infant. However, the relative strength of the reflex response decreased from a mean of 88.3% (range, 34-160%) at approximately 6 wk to 50.3% (range, 26-125%) by 1 yr of age (P < 0.001). All infants showed an increase in Crs with age, with mean Crs increasing from 60.1 +/- 8.9 (SD) to 149.0 +/- 20.6 ml/kPa between 6 wk and 1 yr. However, there was no apparent relationship between the magnitude of decline in HBR response and the age-related changes in Crs.(ABSTRACT TRUNCATED AT 250 WORDS)
Aging↗
Analysis of tidal breathing parameters in infancy: how variable is TPTEF:TE?
During recent years there has been increasing interest in the measurement of tidal breathing parameters, such as the time to reach peak tidal expiratory flow as a proportion of total expiratory time (TPTEF:TE), and their application to population-based studies of the determinants of early respiratory morbidity. However, little is known about factors influencing the within and between-subject variability of these parameters. This study examines the influence of sedation on TPTEF:TE, estimates the optimal number of breaths and breath epochs required to measure TPTEF:TE, and assesses short-term repeatability of this parameter during the first year of life, taking account of age-related differences. Measurements were made in 266 healthy infants and young children (1 d to 19 mo old). Mean (SD) TPTEF:TE fell from 0.49 (0.11) in the first 2 wk of life to 0.34 (0.09) by 5 to 8 wk, remaining similar thereafter. Sedation with triclofos sodium (75 mg/kg) had no significant effect on TPTEF:TE, which was 0.33 (0.10) in 23 unsedated 6-wk-old infants and 0.32 (0.08) in 49 sedated infants of similar age and weight (95% CI for the difference: -0.05, 0.04). At least 10 breaths in each of two separate epochs from each infant were required to provide a representative estimate of TPTEF:TE. The mean (SD) difference between repeat measurements made 5 to 108 min apart was 0.02 (0.08) in 34 infants younger than 6 wk of age (95% limits of agreement: -0.15, 0.18) and -0.01 (0.04) (95% limits of agreement -0.09, 0.08) in 30 infants 6 wk and older.(ABSTRACT TRUNCATED AT 250 WORDS)
Age Factors↗
Comparison of nitrogen washout and plethysmographic measurements of lung volume in healthy infants.
Functional residual capacity (FRC), the only lung volume to be assessed routinely in infants, can be measured using plethysmography or gas dilution. Although it is well recognized that both methods yield similar FRC values in healthy adults, gas dilution techniques have consistently produced lower values in healthy infants when compared with plethysmography. However, interpretation of this difference is difficult since data comparing the different techniques within the same infants have rarely been reported. We performed paired measurements of FRC using an automated open-circuit nitrogen washout technique (FRCN2) and whole-body plethysmography (FRCpleth) in 11 healthy infants with a median age of 12 months (range, 2 to 18 months). The mean (SD) FRC was 21.7 (4.0) ml/kg for the N2 washout and 25.6 (4.9) ml/kg for plethysmography. The mean within-subject difference between FRCN2 and FRCpleth was 3.9 (range, -0.3 to 7.2) ml/kg (p = 0.001). Both N2 washout and plethysmography yielded reproducible results, with the mean of the coefficients of variation (CV) being 3.6 and 3.9%, respectively. The results from these paired measurements support previously reported data from separate populations of infants which suggest that gas dilution techniques consistently yield smaller values for FRC than do those measured by plethysmography.
Female↗
Respiratory compliance in infants--a preliminary evaluation of the multiple interrupter technique.
Measurements of total respiratory system compliance (Crs) using the multiple occlusion technique (MOT) in spontaneously breathing infants can be difficult to interpret in the presence of an unstable end-expiratory level. Similarly, measurements using the passive flow volume technique (PFV) are invalidated if there is alinearity of the expiratory time constant (Trs), irrespective of respiratory effort. For possibly overcoming these problems, we assessed the feasibility of a technique using multiple interruptions of of a single expiration (MIT), obtaining several pairs of volume-pressure data, from one expiration, which relate to a single end-expiratory level. Crs was measured in 16 infants aged 0.5 to 20 months using the MOT, MIT, and PFV technique. The MOT and the MIT each failed in one (different) infant, both succeeding where the other failed. The PFV technique failed in five infants in whom no acceptable plateau of airway pressure during occlusion and no Trs could be obtained from a single breath. Failure to obtain a linear Trs was accompanied by failure of the MIT in only one infant. Individual differences between the MIT and the MOT were less than 9%. However, the PFV measurements varied from -16.3% and +25.7% of the values from MIT or MOT. The greatest differences between Crs values coincided with the greatest differences between volume intercepts of the extrapolated volume-pressure (MOT, MIT) and flow-volume (PFV) data. From this preliminary study, the MIT proved as successful as the MOT, requiring fewer occluded breaths to measure Crs. In infants with a rapid respiratory rate, the data from several expirations can be merged and analyzed as for the MOT.
Humans↗
Influence of sedation on the Hering-Breuer inflation reflex in healthy infants.
The airway occlusion technique for measuring passive respiratory mechanics in infants relies on an ability to evoke the Hering-Breuer inflation reflex (HBR). However, the persistence of this reflex beyond the early newborn period remains controversial. We have recently demonstrated that there is no change in the strength of this reflex during the first two months of life in healthy infants during natural sleep. Measurements beyond this immediate newborn period are difficult without sedation, but it is unclear whether sedation itself may influence this reflex. To investigate the influence of sedation, the HBR was measured in 66 healthy, full-term infants aged 4-8 weeks. Thirty-three infants were measured during natural sleep, and 33 after triclofos sodium sedation (75 mg.kg-1). The strength of the HBR was assessed from the change in expiratory time (TE) following brief end-inspiratory airway occlusion, as compared to TE during spontaneous breathing. The mean increase in TE following occlusion was 89.45% (SD, 29.8; range, 44-175) in infants sleeping naturally, and 92.42% (SD, 31.2; range, 34-179) in sedated infants. Using unpaired t tests, no statistically significant difference was found between groups (P = 0.7516). We conclude that the strength of the HBR in healthy infants is not influenced by sedation with triclofos sodium, in doses normally used for lung function testing.
Female↗
A national survey of nebuliser use.
Nebuliser drug delivery units were reused in 15% of paediatric wards participating in a national survey, while routine servicing and written information was provided by only half the wards issuing home nebulisers. Written information should be developed as a national resource, and further research on optimal cleaning practices is required.
Asthma↗
Recognition and early management of Reye's syndrome.
Reye's syndrome continues to be associated with a high mortality. Out of 12 cases treated on our intensive care unit over a four year period, seven died, one suffered minimal cerebral damage, and four were normal. Rapid progression through coma stages and high peak ammonia concentrations worsened prognosis. Reye's syndrome was suspected in only 50% of cases at the referring hospital and resulted in prompt referral to the intensive care unit in only one case. Late referral to the unit was associated with a poor outcome. Sudden neurological deterioration followed diagnostic lumbar puncture in six children. Papilloedema was an unreliable sign of raised intracranial pressure and was absent in all cases. While computed tomography of the brain was useful in providing additional evidence of raised intracranial pressure, this could only be confirmed by direct measurement. Lumbar puncture in the presence of rapidly progressive coma should be deferred until raised intracranial pressure has been excluded. To this end, early admission to a paediatric intensive care unit with facilities for computed tomography and monitoring of intracranial pressure is recommended.
Child↗
Micropenis: an important early sign of congenital hypopituitarism.
Explore the source record for details and available documents.
Humans↗
Neonatal hyperparathyroidism.
We describe a girl with congenital hyperparathyroidism who presented soon after birth with respiratory distress, hypotonia, feeding difficulties, and bone deformities. Hypercalcaemia, hypophosphataemia, and raised alkaline phosphatase were present and plasma parathyroid hormone levels measured by radioassay and bioassay were raised. X-rays showed gross demineralisation with metaphyseal fractures, erosions, and sub-periostal reaction along the bones. Following surgical removal of four hyperplastic parathyroid glands and subsequent maintainance therapy with 1-alpha-hydroxycholecalciferol there has been virtually complete reversal of her bone abnormalities.
Female↗