Biomedical subjects
Publications and source records attributed to A Greenough.
Exhaled nitric oxide (eNO) levels were measured in eight ventilated infants, mean gestational age 25.8 (SD 1.7) weeks and postnatal age 55 (SD 39) days, before and after three days of dexamethasone treatment. The eNO levels fell from a mean of 6.5 (SD 3.4) to 4.2 (SD 2.6) parts per billion (p = 0.031) and the mean supplementary oxygen levels from 62% to 45% (p = 0.0078).
The aim of the study was to determine if prematurely born children who had suffered intra-uterine growth retardation (IUGR) had more severe lung function abnormalities than those born an appropriate weight for gestational age (AGA). Analysis of the lung function results of 119 infants (median (range) gestational age of 30 (23-35) weeks) was undertaken. In total, 31 of the infants had suffered IUGR and were born small for gestational age (SGA). Functional residual capacity and airways resistance (Raw) were measured at a median post-natal age of 10 (6-24) months. Specific airway conductance (sGaw) was calculated from thoracic gas volume and Raw. The SGA children were born at a greater gestational age and had a lower body weight at testing than the AGA children. Raw and sGaw differed between the SGA and AGA children. Regression analysis demonstrated that lung volumes were significantly related to body weight at testing, Raw was related to IUGR, maternal smoking and bronchopulmonary dysplasia, and sGaw to maternal smoking. In conclusion, these results suggest that prematurely born infants who have suffered intra-uterine growth retardation may be at increased risk of impaired lung function at follow-up.
BACKGROUND: Adults with sickle cell disease (SCD) have restrictive lung function abnormalities which are thought to result from repeated lung damage caused by episodes of pulmonary vaso-occlusion; such episodes start in childhood. A study was therefore undertaken to determine whether children with SCD have restrictive lung function abnormalities and whether the severity of such abnormalities increases with age. METHODS: Sixty four children with SCD aged 5-16 years and 64 ethnic matched controls were recruited. Weight and sitting and standing height were measured, and lung function was assessed by measurement of lung volumes and forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF) before and after bronchodilator. RESULTS: Compared with the control subjects, the children with SCD had lower mean (SD) sitting height (69 (6.3) cm v 73 (7.7) cm; p=0.004), sitting:standing height ratio (0.50 (0.02) v 0.51 (0.01); p<0.0001), weight (33 (10.9) kg v 41 (14.9) kg; p=0.001), functional residual capacity measured by a helium gas dilution technique (1.2 (0.3) l v 1.3 (0.4) l; p=0.04), FEV1 (1.5 (0.5) l v 1.9 (0.7) l; p=0.0008), FVC (1.7 (0.6) l v 2.1 (0.8) l; p=0.001), and PEF (3.9 (1.3) l/s v 4.8 (1.5) l/s; p=0.0004). The effect of age on lung function differed significantly between the children with SCD and the controls for total lung capacity and vital capacity measured by plethysmography and functional residual capacity measured by helium gas dilution. CONCLUSION: Lung function differs significantly in children with SCD compared with ethnic matched controls of a similar age. Our results suggest that restrictive abnormalities may become more prominent with increasing age.
BACKGROUND: Infants with severe respiratory failure are frequently transferred to high volume strategy, high frequency oscillation (HFO). Mean airway pressure (MAP) is then elevated, the aim being to open up atelectatic lungs and hence improve gas exchange. AIM: To test the hypothesis that lung volume prior to transfer would predict the response to high volume strategy HFO and identify which factors related to poor outcome (death). METHODS: Lung volume was assessed by measurement of functional residual capacity (FRC) and the response to HFO determined by the change in the alveolar arterial gradient (AaDO2) on transfer from conventional mechanical ventilation (CMV) to the optimal MAP on high volume strategy HFO. PATIENTS: Forty-two infants with a median gestational age of 28 (range 23 to 40) wk were studied. RESULTS: FRC prior to transfer correlated significantly with the change in MAP necessary to optimize oxygenation (p = 0.012), but not the change in AaDO2 in response to HFO. There were no significant differences in the lung volumes of survivors and non-survivors, but those who died were more immature (p = 0.0009) and had a smaller response to HFO (p = 0.035). CONCLUSION: Lung volume prior to transfer to high volume strategy HFO might be helpful to guide oscillatory settings, but is a poor predictor of the response to high volume strategy HFO.
Our objective was to determine the effect of posture on respiratory function and drive in prematurely born infants immediately prior to discharge. Twenty infants (6 oxygen-dependent), median gestational age 29 weeks (range, 25-32), were studied at a median postconceptional age (PCA) of 36 weeks (range, 33-39). On 2 successive days, infants were studied both supine and prone; each posture was maintained for 3 hr. The order on each day in which postures were studied was randomized between infants. At the end of each 3-hr period, tidal volume (Vt), inspiratory (Ti) and expiratory (Te) time, respiratory rate, and minute ventilation were measured. In addition, respiratory drive was assessed by measuring the pressure generated in the first 100 msec of an imposed airway occlusion (P(0.1)), and respiratory muscle strength was assessed by recording the maximum inspiratory pressure (Pimax) generated against an occlusion which was maintained for at least five breaths. Overall, tidal volume was higher (P < 0.05), but respiratory rate (P < 0.05), P(0.1) (P < 0.05), and Pimax (P < 0.05) were lower in the prone compared to the supine position. There were no significant differences in Ti or Te between the two postures. In oxygen-dependent infants only, minute volume was higher in the prone position (P < 0.05). In conclusion, posture-related differences in respiratory function are present in prematurely born infants studied prior to neonatal unit discharge.
This randomised, double-blind, double-dummy, parallel group, multicentre study compared the efficacy and tolerability of lercanidipine with lacidipine. Elderly patients with isolated systolic hypertension (supine blood pressure >/=160/<95 mmHg) were enrolled and underwent a placebo run-in period of 14-27 days before random allocation to lercanidipine tablets 10 mg once daily (n=111) or lacidipine tablets 2 mg once daily (n=111) for the assessment period (112-160 days). Titration to lercanidipine 20 mg once daily (two 10 mg tablets) or lacidipine 4 mg once daily (two 2 mg tablets) was allowed after 8 weeks, if required. Both treatments decreased supine and standing systolic and diastolic blood pressure between the end of the run-in period and the end of the assessment period (P<0.0001). At the end of the assessment period, the estimated mean treatment difference (95% confidence intervals) in supine systolic blood pressure was -0.81 (-4.45, 2.84) mmHg. These confidence intervals were within the limits specified for equivalence, that is, (-5, 5) mmHg. Ambulatory blood pressure monitoring showed that the antihypertensive effects of both drugs lasted for the full 24-h dosing period and followed a circadian pattern. Both treatments were well tolerated with a low incidence of adverse drug reactions and a low withdrawal rate. Significantly fewer patients withdrew from treatment with lercanidipine (P=0.015). Neither treatment had any clinically significant effect on pulse rate or cardiac conduction. In conclusion, both treatments were equally effective in controlling supine systolic blood pressure in patients with isolated systolic hypertension.
AIMS: Infants with neonatal abstinence syndrome (NAS) may require a prolonged neonatal unit admission, which has implications for both their families and bed occupancy. The aim of this study was to test the hypothesis that the duration of neonatal unit stay would be influenced by the type of maternal drug use and particularly prolonged for the infants whose mothers had taken methadone with other substances. DESIGN: The medical records of infants born at term who were admitted consecutively to a neonatal unit because of NAS were reviewed. Data were collected regarding antenatal and neonatal factors likely to affect neonatal stay. Comparisons were then made between three groups of infants: those whose mothers took methadone alone, methadone plus other drugs or non-methadone opioids. SETTING: Level three neonatal intensive care unit. PARTICIPANTS: Forty-one infants with a median gestational age of 39 (range 37-42) weeks. FINDINGS: The 41 infants had a median duration of admission of 30 (range 3-68) days. Thirty-six of the infants required treatment for NAS; their median duration of treatment was 29 (range 6-68) days. The duration of stay and requirement for treatment were greater in the infants exposed to methadone and other drugs compared to those exposed to non-methadone opiods only (P = 0.0212, P = 0.0343, respectively). The duration of stay without requirement for treatment was also longest in the methadone plus other drugs group (P = 0.0117). CONCLUSIONS: Prolonged treatment and neonatal unit stay are influenced by the type of maternal drug abused.
UNLABELLED: The occurrence of an intestinal perforation in a prematurely born infant following rectal administration of a calcium resonium resin prompted a literature review to determine whether use of resins in neonates was evidence based. This revealed that the results of anecdotal series suggested that resins were useful, but the only randomized trial including prematurely born infants demonstrated that resins were less efficacious than glucose and insulin infusions. Important side effects were reported including colonic necrosis and impaction with perforation. CONCLUSION: The risks and benefits of exchange resins in prematurely born infants should be assessed in an appropriately sized randomized trial.
Neonatal abstinence syndrome (NAS) is suffered by infants withdrawing from substances on which they have become physically dependent after in utero exposure. They may require prolonged treatment and spend weeks or even months in hospital. A wide range of drugs have been used to treat NAS. The efficacy of few, however, have been adequately investigated. Evidence suggests that opioids are the most appropriate, at least in infants exposed to diamorphine or methadone. In all "head to head" trials, diazepam has been shown to be ineffective. Morphine and methadone are currently the most commonly prescribed opioids to treat NAS, but randomised trials have not been undertaken to determine which is the more beneficial. Many infants with NAS have been exposed to multiple substances in utero. Further research is required into whether a single opiate or a multiple drug regimen is the best option for such patients.
A 26 week gestation infant had an increasingly elevated right hemidiaphragm following drainage of bilateral pleural effusions and failed extubation on numerous occasions. Electric stimulation of the phrenic nerves revealed absent activity on the right, indicating phrenic nerve injury from chest tube drain insertion. Diaphragmatic plication was performed and the infant successfully extubated four days later.
OBJECTIVE: To determine if chest radiograph appearance at 28 days or 36 weeks postmenstrual age (PMA) can predict recurrent wheeze or cough at follow up in prematurely born infants more effectively than readily available clinical data. DESIGN: Chest radiographs of infants entered into the UKOS trial, who had had a chest radiograph at 28 days and 36 weeks PMA and completed six months of follow up, were assessed for the presence of fibrosis, interstitial shadows, cystic elements, and hyperinflation. At 6 months of corrected age, the occurrence and frequency of wheeze and cough since discharge were determined using a symptom questionnaire. PATIENTS: A total of 185 infants with a median gestational age of 26 (range 23-28) weeks. RESULTS: Thirty seven infants wheezed more than once a week, compared with the rest of the cohort. These infants had significantly higher chest radiograph scores at 28 days (p = 0.020) and 36 weeks PMA (p = 0.005), with significantly higher scores at 28 days for fibrosis (p = 0.017) and at 36 weeks PMA for fibrosis (p = 0.001) and cystic elements (p = 0.0007). They had also been ventilated for longer (p = 0.013). Forty four infants coughed more than once a week; they did not differ significantly from the rest of the cohort. An abnormal chest radiograph score at 36 weeks PMA had the largest area under the receiver operator characteristic curve with regard to prediction of frequent wheeze. CONCLUSION: An abnormal chest radiograph appearance at 36 weeks PMA predicts frequent wheeze at follow up and appears to be a better predictor than readily available clinical data.
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UNLABELLED: Hyperphagia, a classical feature of neonatal drug withdrawal, has been reported not to lead to excessive weight gain, but this is contrary to our clinical experience. The aim of this study was to determine whether infants with neonatal drug withdrawal suffered excessive weight gain because of hyperphagia and, if so, to determine the risk factors. The study population comprised 48 infants consecutively admitted to the neonatal intensive care unit, 11 of whom gained weight by more than 20 g kg(-1) d(-1) for at least 10 d (excessive weight gain). All 11 infants were hyperphagic (>200 ml/kg) for at least part of the excessive weight gain period. During the perinatal period, the 11 infants had a greater fluid intake (p < 0.01) but similar weight gain to gestational-age-matched, neonatal drug-withdrawal infants who did not suffer any excessive weight gain. Compared to the rest of the cohort, the infants with excessive weight gain were more likely to require treatment with morphine/chlorpromzaine (p < 0.05) and had a higher maximum withdrawal score (p < 0.01). CONCLUSION: Hyperphagia can lead to excessive weight gain in infants with neonatal drug withdrawal. Our results suggest that hyperphagia occurs in those who require treatment for severe withdrawal.
Plethysmographic measurement of airway resistance (R(aw)) has been determined by single-point analysis, usually at 50% of maximum inspiratory flow (MIF). Computer-assisted (best fit) analysis, however, allows R(aw) to be calculated by applying a regression line to any portion of the plethysmograph pressure-flow loop. We determined whether the results of best fit analysis using a computer program, sampling at 200 Hz, were influenced by the portion of the inspiratory loop analysed and if best fit or single-point analysis gave more reproducible results. Twenty infants of median gestational age 26 (range 24-28) weeks, were studied at a median age of 12 (12-14) months corrected for prematurity. R(aw) was calculated by best fit analysis between 0 and 33% MIF, 0 and 50% MIF and 0 and 67% MIF and single-point analysis at 50% of MIF. Similar mean R(aw) values were obtained by best fit analysis between 0 and 33% MIF (2.79 kPa/(l/s)) and 0 and 50% MIF (3.01 kPa/(l/s)) and single-point analysis at 50% MIF (2.86 kPa/(l/s)), but best fit analysis between 0 and 67% gave higher results (3.60 kPa/(l/s)), p < 0.0001. Within the linear portion of the inspiratory loop, the mean intrasubject coefficient of variation was lowest for best fit analysis between 0 and 50% MIF. Best fit computerized analysis between 0 and 50% MIF is recommended as the analysis of choice.
OBJECTIVES: To determine whether the rehospitalisation and primary care requirements of infants with chronic lung disease (CLD) during the first two years after birth were influenced by a requirement for supplementary oxygen after discharge from the neonatal intensive care unit. METHODS: Review of records from both the hospital and general practitioner. PATIENTS: 235 infants, median gestational age 27 (range 22-31) weeks, 88 of whom were receiving supplementary oxygen when discharged home. RESULTS: Overall, the infants required a median of 2 (range 0-20) admissions per patient, 8 (0-41) outpatient attendances, 13 (0-76) contacts with the general practitioner, and 17 (0-169) consultations with other primary healthcare professionals. The home oxygen patients required significantly more and longer admissions (p < 0.01) and more outpatient attendances (p < 0.05). The total cost of care per infant of the home oxygen group was greater (p < 0.001); this reflected higher costs for hospital stay (p < 0.01), total inpatient care (p < 0.01), and primary care drugs (p < 0.01). CONCLUSION: Despite routine use of antenatal steroids and postnatal surfactant, certain patients with CLD, particularly those who receive home oxygen treatment, show high rates of utilisation of health service resources after discharge from the neonatal care unit.
Height and weight were measured and body mass index (BMI) calculated in 56 sickle cell disease (SCD), 57 Caucasian (CC), and 63 African/Caribbean (AC) 3-9 year old children. The SCD children were taller, but had similar weight and BMI to the CC controls. The SCD group had lower weight and BMI than the AC controls. The AC controls were of greater height, weight, and BMI than CC controls. These data highlight the importance of using ethnically appropriate reference ranges.
OBJECTIVE: To identify whether the results of assessment of respiratory muscle strength or respiratory load were better predictors of extubation failure in preterm infants than readily available clinical data. PATIENTS: Thirty six infants, median gestational age 31 (range 25-36) weeks and postnatal age 3 (1-14) days; 13 were < 30 weeks of gestational age. METHODS: Respiratory muscle strength was assessed by measurement of maximum inspiratory pressure generated during airway occlusion, and inspiratory load was assessed by measurement of compliance of the respiratory system. RESULTS: Overall, seven infants failed extubation-that is, they required reintubation within 48 hours. These infants were older (p < 0.01), had a lower gestational age (p < 0.01), and generated lower maximum inspiratory pressure (p < 0.05) than the rest of the cohort. Similar results were found in the infants < 30 weeks of gestational age. Overall and in those < 30 weeks of gestational age, gestational age and postnatal age had the largest areas under the receiver operator characteristic curves. CONCLUSION: In very premature infants, low gestational age and older postnatal age are better predictors of extubation failure than assessment of respiratory muscle strength or respiratory load.
OBJECTIVE: To determine if differences in respiratory muscle strength could explain any posture related effects on oxygenation in convalescent neonates. METHODS: Infants were examined in three postures: supine, supine with head up tilt of 45 degrees, and prone. A subsequent study was performed to determine the influence of head position in the supine posture. In each posture/head position, oxygen saturation (SaO2) was determined and respiratory muscle strength assessed by measurement of the maximum inspiratory pressure (PIMAX). PATIENTS: Twenty infants, median gestational age 34.5 weeks (range 25-43), and 10 infants, median gestational age 33 weeks (range 30-36), were entered into the first and second study respectively. RESULTS: Oxygenation was higher in the prone and supine with 45 degrees head up tilt postures than in the supine posture (p<0.001), whereas PIMAX was higher in the supine and supine with head up tilt of 45 degrees postures than in the prone posture (p<0.001). Head position did not influence the effect of posture on PIMAX or oxygenation. CONCLUSION: Superior oxygenation in the prone posture in convalescent infants was not explained by greater respiratory muscle strength, as this was superior in the supine posture.