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Biomedical subjects

O Bamford

Publications and source records attributed to O Bamford.

12 recordsLinked to original sources
PubMed2001

Focus group interviews to examine the role and development of the clinical nurse specialist.

This paper reports on the use of focus groups to investigate the development of clinical nurse specialist roles. The need for this project was identified during initial research, undertaken in two London Hospital Trusts, to assess the variety and nature of advanced clinical nursing roles already in evidence. From analysis of these data, this second stage of the research developed, in which the future of the clinical nurse specialist role within these two trust settings was explored. The initial steps of grounded theory, analytical techniques and procedures, using a constant comparative method, were used to analyse the findings from five focus groups (composed of a total of 25 nurses from two trusts). From the data, six categories were identified; role components; experience versus education; supportive strategies; personal qualities; future role development and development strategies. These categories provide the framework for discussing the findings of the research, within the context of the available literature. This examination of the clinical nurse specialist role highlights issues for career progression and education strategies. Both will need careful planning, in order for the clinical nurse specialist role to be considered and evolve as part of a potential strategy for the development of nursing roles within the two trusts and on a national level.

Clinical Competence↗
PubMed2000

The clinical nurse specialist: perceptions of practising CNSs of their role and development needs.

This study was carried out to determine the role and development needs of Clinical Nurse Specialists (CNSs) in two acute hospital trusts. One of the aims was to obtain a detailed understanding of the current professional experience of Clinical Nurse Specialists. Data were collected using focus groups and analysed descriptively. Analysis of the content was qualitative, based on a grounded theory approach, and followed the initial steps of open and axial coding. Role transition and development needs are identified on a continuum of novice to expert.

Acute Disease↗
PubMed1999

Response to inspiratory resistive loading during sleep in normal children and children with obstructive apnea.

The response to inspiratory resistance loading (IRL) of the upper airway during sleep in children is not known. We, therefore, evaluated the arousal responses to IRL during sleep in children with the obstructive sleep apnea syndrome (OSAS) compared with controls. Children with OSAS aroused at a higher load than did controls (23 +/- 8 vs. 15 +/- 7 cmH(2)O. l(-1). s; P < 0.05). Patients with OSAS had higher arousal thresholds during rapid eye movement (REM) vs. non-REM sleep (P < 0.001), whereas normal subjects had lower arousal thresholds during REM (P < 0.005). Ventilatory responses to IRL were evaluated in the controls. There was a marked decrease in tidal volume both immediately (56 +/- 17% of baseline at an IRL of 15 cmH(2)O. l(-1). min; P < 0.001) and after 3 min of IRL (67 +/- 23%, P < 0.005). The duty cycle increased. We conclude that children with OSAS have impaired arousal responses to IRL. Despite compensatory changes in respiratory timing, normal children have a decrease in minute ventilation in response to IRL during sleep. However, arousal occurs before gas-exchange abnormalities.

Airway Resistance↗
PubMed1998

Arousal and ventilatory responses during sleep in children with obstructive sleep apnea.

Abnormal central regulation of upper airway muscles may contribute to the pathophysiology of the childhood obstructive sleep apnea syndrome (OSAS). We hypothesized that this was secondary to global abnormalities of ventilatory control during sleep. We therefore compared the response to chemical stimuli during sleep between prepubertal children with OSAS and controls. Patients with OSAS aroused at a higher PCO2 (58 +/- 2 vs. 60 +/- 5 Torr, P < 0.05); those with the highest apnea index had the highest arousal threshold (r = 0.52, P < 0.05). The hypercapnic arousal threshold decreased after treatment. For all subjects, hypoxia was a poor stimulus to arousal, whereas hypercapnia and, particularly, hypoxic hypercapnia were potent stimuli to arousal. Hypercapnia resulted in decreased airway obstruction in OSAS. Ventilatory responses were similar between patients with OSAS and controls; however, the sample size was small. We conclude that children with OSAS have slightly blunted arousal responses to hypercapnia. However, the overall ventilatory and arousal responses are normal in children with OSAS, indicating that a global deficit in respiratory drive is not a major factor in the etiology of childhood OSAS. Nevertheless, subtle abnormalities in ventilatory control may exist.

Arousal↗
PubMed1996

Developmental expression of tyrosine hydroxylase, D2-dopamine receptor and substance P genes in the carotid body of the rat.

Alterations in the level of putative neurotransmitters/neuromodulators and corresponding receptors may be a possible mechanism involved in changes in chemosensitivity of peripheral chemoreceptors in the carotid body during development. Using quantitative in situ hybridization histochemistry, levels of messenger RNAs encoding tyrosine hydroxylase, the rate-limiting enzyme for dopamine synthesis, the D2-dopamine receptor and substance P of newborn rats at postnatal days 0, 2, 14 and 21 were determined. For comparison, during the same time points during development, we also determined the level of expression of these messenger RNAs in the cells of the superior cervical ganglion which are not chemosensitive. Tyrosine hydroxylase and D2-dopamine receptor messenger RNAs were co-localized in many of the cells in both the carotid body and the superior cervical ganglion. In the carotid body, the level of tyrosine hydroxylase messenger RNA expression was greatest at birth, significantly decreased by 48 h postnatal age and remained decreased at 14 and 21 postnatal days. In contrast, D2-dopamine receptor messenger RNA levels significantly increased with postnatal age in the carotid body. This profile of an D2-dopamine receptor was not observed in the superior cervical ganglion where tyrosine hydroxylase and D2-dopamine receptor messenger RNAs levels did not significantly change from postnatal days 0 to 21. Lastly, in the rat carotid body, substance P messenger RNA was not detected. However, substance P messenger RNA was abundant in the nodose and petrosal ganglion. The increasing contribution of carotid body on ventilation with increasing postnatal age is associated with changes in levels of gene expression for tyrosine hydroxylase and D2-dopamine receptor in the carotid body.

Animals↗
PubMed1995

Correlation of cervical auscultation with physiological recording during suckle-feeding in newborn infants.

Pharyngeal swallows during infant suckle-feeding are associated with a characteristic sequence of sounds audible by stethoscope or by an accelerometer or microphone held over the larynx. In rhythmically feeding term-born neonates, the delineating acoustic elements are discrete sounds which precede and succeed pharyngeal swallows. Digital signal processing shows similarities in morphological detail between the discrete sounds preceding swallows and between those succeeding swallows; those succeeding swallows are more variable in temporal relation to swallows, amplitude and morphological detail. Variations in the pattern of interswallow respiration, including apnea, are correlated with variations in the discrete sounds. Specification of physiological correlates of these internal feeding sounds increases the utility of cervical auscultation as a method of investigation and of clinical observation of feeding.

Auscultation↗
PubMed1995

Supplemental oxygen during sleep in children with sleep-disordered breathing.

Supplemental O2 is sometimes used to treat children with the obstructive sleep apnea syndrome (OSAS). However, its effects have not been studied. We therefore evaluated the use of supplemental O2 during sleep in children with OSAS. Oxygen and room air were delivered via nasal cannula at 1 L/min for 4 h each in a randomized, double-blind fashion. Twenty-three children were studied (mean age, 5 +/- 3 [SD] yr). Patients had a higher mean SaO2 and higher SaO2 nadir when breathing O2. There was no difference in the number (10.9 +/- 20.6/h on O2 versus 13.5 +/- 19.3 on room air) or duration of obstructive apneas. Although there was no overall change in end-tidal PCO2 when patients breathed O2, two children showed a significant increase. We conclude that breathing supplemental O2 during sleep in children with OSAS results in improved oxygenation and in most cases does not exacerbate sleep-disordered breathing. However, end-tidal PCO2 should be monitored in children with OSAS receiving O2 therapy. We speculate that supplemental O2 does not depress the ventilatory drive during sleep in most children with OSAS.

Child↗
PubMed1992

The relationship between rhythmic swallowing and breathing during suckle feeding in term neonates.

Little is known of the development of efficient coordination between suckle feeding and breathing in human infants. To establish baseline data, we recorded breathing and swallowing activity during bottle feeds in 23 infants at 14-48 h postnatal age. Most swallows (overall mean 68%) were organized into runs, with intervals starting at 0.6-0.8 s and slowing to 1-1.3 s after 30-40 s. The proportion of run swallows to total swallows increased significantly with age. Swallow intervals were regular (coefficient of variation = 18-38%) compared with breathing (coefficient of variation = 50%). Both breathing rate and tidal volume were significantly reduced by the onset of suckle feeding, and the pattern of respiratory airflow became markedly irregular. Mild transient desaturation was common, but was not accompanied by changes in heart rate. Swallows could occur in all phases of breathing. Overall, equal numbers of swallows were preceded by expiration and inspiration, but twice as many were followed by expiration compared with inspiration. Swallows were classified by the respiratory phases both preceding and following the swallow. Swallows occurred in all possible classifications in each of the infants studied. The incidence of the most frequent classification (inspiration-swallow-expiration), was 24% overall (individual range 5-50%). The phase relation between swallows and breaths changed frequently but showed occasional short periods of stability during which the breathing became regular and tidal volume increased. We conclude that at less than 48 h the normal infant has little coordination between swallowing and breathing rhythms and maintains rhythmic swallowing at the expense of eupnea.

Bottle Feeding↗
PubMed1990

Central effects of an alpha 2-adrenergic antagonist on fetal lambs: a possible mechanism for hypoxic apnea.

In 12 chronically-prepared fetal lambs at 128-135 days gestation, a specific alpha 2-antagonist, L-657,743 (Merck) was infused into a lateral cerebral ventricle for periods of up to 24 h. Control infusions of artificial CSF had no effect. L-657,743 at a dose rate sufficient to block the actions of injected clonidine did not affect breathing incidence or episode duration, electrocortical activity, heart rate, arterial pressure or blood gases during normoxic conditions. However, 5 out of 6 preparations receiving L-657,743 while hypoxic continued to breathe during hypoxia instead of becoming apneic as normal. The central effects of alpha 2-adrenergic blockade appear to be specific to hypoxia. It is concluded that fetal hypoxic apnea may be mediated by inhibitory alpha 2-adrenergic receptors which can be blocked by the antagonist L-657,743.

Adrenergic alpha-Antagonists↗