Browsing by Author "Smith, J."
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- ItemBirth weight and early lung compliance as predictors of short-term outcome in premature infants with respiratory distress syndrome(Health & Medical Publishing Group, 1995-11) Smith, J.; Van Lierde, S.; Devlieger, H.; Daniels, H.; Eggermont, E.ENGLISH ABSTRACT: In addition to birth weight (BW), respiratory mechanics measured during the first week of life have been reported to predict outcome in ventilated newborn infants with respiratory distress syndrome(RDS). Most measuring techniques are invasive, requiring the placement of an oesophageal tube or balloon. In the present study the compliance (Crs) and resistance (Rrs) of the total respiratory system were measured without an oesophageal tube, using a commercially available system (PEDS; MAS Inc., Hatfield, Pa.). The Crs and Rrs were determined once, within 24 hours of birth, in 28 preterm infants requiring mechanical ventilation for RDS. Variables such as gestational age (GA) and BW were also evaluated for their predictive role in outcome. Poor outcome was defined as death from respiratory failure or the development of bronchopulmonary dysplasia (BPD) at 28 days. All non-survivors died of refractory respiratory failure, at a median age of 6 days. The median Crs of the 21 survivors was 0.5 ml/cm H2O and of the non-survivors 0.21 ml/cm H2O (P = 0.01). Crs below 0.45 ml/cm H2O predicted 15 of the 16 infants who either developed BPD or died (positive predictive value 100%; negative predictive value 92%; sensitivity 94%; specificity 100%). Nine survivors, who subsequently developed BPD, had a median Crs of 0.38 ml/cm H2O. Their Crs was significantly lower than that of the infants without evidence of BPD (Crs = 0.61 ml/cm H2O) (P = 0.01). All of the 12 babies without BPD who survived had median Crs values above 0.45 ml/cm H20. The median Rrs of the 9 infants with BPD (96 cm H2O/l/s) was also significantly higher than the Rrs value of the non-BPD group (59 cm H2O/l/s) (P = 0.05). When stepwise multiple logistic regression was applied to predict outcome, the only variable that could be entered at a 0.05 level of significance was BW. Uncorrected compliance entered the second step, but did not reach statistical significance. We conclude that in premature infants with RDS, BW is a strong predictor of outcome. Although determination of the Crs within the first 24 hours after birth did not add significance to this predictive model, it was nevertheless a useful parameter to determine respiratory morbidity and mortality.
- ItemBorn too soon, too small, to die - a plea for a fair innings(Health & Medical Publishing Group, 1999) Smith, J.; Pieper, C. H.; Kirsten, G. F.[No abstract available]
- ItemCompliance of the respiratory system as a predictor for successful extubation in very-low-birth-weight infants recovering from respiratory distress syndrome(Health & Medical Publishing Group, 1999) Smith, J.; Pieper, C. H.; Maree, D.; Gie, R. P.Objective. To develop additional criteria to predict for successful extubation of very-low-birth-weight infants recovering from respiratory distress syndrome. Design. Prospective study. Setting. Neonatal intensive care unit at a university teaching hospital. Interventions. Infants ready for extubation according to clinical, ventilatory and blood gas criteria were studied. Before extubation, tidal volume (Vt), minute ventilation, respiratory rate/Vt and mean inspiratory flow were measured during two different ventilatory settings: (i) during intermittent mandatory ventilation (IMV); and (ii) while breathing spontaneously with endotracheal continuous positive airway pressure (CPAP). Tidal volume was obtained through electronically integrated flow measured by a hot-wire anemometer. Total respiratory compliance (Crs) was determined during IMV and was derived from the formula Vt/PIP-PEEP, where the difference between peak inspiratory pressure (PIP) and positive end-expiratory pressure (PEEP) represented the ventilator inflation pressure. Measurements and main results. Each of 49 infants was studied once before extubation. 33 infants (67%) were successfully extubated and 16 (32.6%) required reintubation. Infants in the success and failure groups were matched for gestation, post-conceptional age, study weight and methylxanthine therapy at the time of study. Successful extubation was associated with a higher mean absolute Crs value (ml/cm H2O) specific Crs value (standardised for body length; ml/cm H2O/cm) compared with infants in whom extubation failed (0.67 v. 0.46; P = 0.01 and 0.018 v. 0.014; P = 0.03, respectively). Analysis of ROC curves detected thresholds for Crs (0.5 ml/cm H2O) and Vt (7 ml) for predicting successful extubation. An absolute Crs value 0.5 ml/cm H2O or more improved the likelihood of successful extubation when compared with clinical/ventilator and blood gas criteria. The likelihood of successful extubation was 81% if the Crs value was ≥ 0.5 ml/cm H2O. A tidal volume of 7 ml or more was less sensitive in contributing to successful extubation (sensitivity 69%). The major causes for extubation failure included atelectasis (diffuse and/or localised) and the presence of a patent ductus arteriosus. Conclusions. In addition to following very precise ventilatory criteria for extubation, we found that bedside measurement of total respiratory system compliance added to the likelihood of extubation success in infants recovering from respiratory distress syndrome. Prospective studies are needed to validate the findings of this study.
- ItemThe effect of severe pre-eclampsia on maternal and cord erythrocyte membrane essential fatty acid profiles(Health & Medical Publishing Group, 1998) Kirsten, G. F.; Smuts, C. M.; Tichelaar, H. Y.; Smith, J.; Hall, D.; Faber, M.; Dhansay, M. A.Objective. To examine the effect of severe pre-eclampsia on maternal and cord erythrocyte membrane essential fatty acid profiles. Design. Clinical trial. Setting. Obstetric High Care Unit, Tygerberg Hospital. Patients. Erythrocyte membrane (EM) essential fatty acid profiles were determined in 17 women with severe preeclampsia, in 17 normotensive pregnant women, and in the cord blood of their respective infants. Results. Pre-eclamptic women had lower EM phosphatidylcholine linoleic acid (C18:2n-6; LA) and cclinolenic acid (C18:3n-3; ALA) levels and lower EM phosphatidylethanolamine ALA levels than the normotensive women with lower cord blood docosahexaenoic acid levels (C22:6n-3; DHA) in both phospholipid fractions. All cord blood arachidonic acid (C20:4n-6; AA) levels were higher than the maternal levels. Conclusions. Pre-eclamptic women have lower LA and ALA levels than normotensive pregnant women, but AA and DHA levels in the two groups are similar. The cord blood DHA levels of infants of pre-eclamptic women are lower than those of the infants of normotensive women. Infants born to pre-eclamptic women may need dietary DHA to replenish DHA stores. This can be obtained from breast-milk or from a formula enriched with DHA.
- ItemThe effectiveness and cost of exogenous pulmonary surfactant replacement therapy(Health & Medical Publishing Group, 1995) Smith, J.; Pieper, C.; Gie, R. P.The articles"" recently published on surfactant replacement therapy (SR1) in the treatment of newborn infants with hyaline membrane disease (HMD) being ventilated in a country with limited health resources are both timeous and urgently needed. Surfactant, being an expensive drug, needs to be administered in the most costeffective fashion and for this reason research guidelines for its administration in South Africa are needed. We are concerned that the discussions of this series of articles do not sufficiently emphasise their limitations, as well as the enormous impact of SRT on survival rates and other neonatal morbidities in newborn infants ventilated with HMD.
- ItemFirst do no harm : addressing respiratory morbidity in the newborn and child following elective caesarean section before 39 weeks' gestation(SAMJ, 2009-12) Smith, J.; Alexander, R. J.
- ItemHigh-frequency oscillatory ventilation - rescue treatment for infants with severe respiratory failure(Health & Medical Publishing Group, 1998) Smith, J.; Pieper, C. H.; Kirsten, G. F.; Maree, D.; Van Zyl, J.; Pretorius, M. L.Objective. To assess the efficacy of high-frequency oscillatory ventilation (HFOV) as a rescue mode of therapy in newborn infants with severe respiratory failure poorly responsive or unresponsive to conventional ventilation and supportive management. Design. Prospective, descriptive clinical study. Setting. Tertiary care neonatal intensive care unit. Patients and methods. All infants with radiographic evidence of diffuse bilateral lung disease and failure to maintain adequate blood gas values while receiving conventional support were offered HFOV. Intervention. HFOV, utilising a high-pressure/volume strategy. Outcome variables. Improvement in arterial/alveolar oxygen tension ratio (a/APO2) of the infants subsequent to their transferral to HFOV; survival rate; and outcome of infants weighing more than 2 000 g who met criteria for extracorporeal membrane oxygenation (ECMO). Identifying the infants who met ECMO entry criteria allowed the success of HFOV to be compared with that of ECMO, the 'standard' treatment for infants considered unventilatable. Neonatal complications such as bronchopulmonary dysplasia, intraventricular haemorrhage and air leaks were documented. Results. Conventional support failed in 34 consecutive infants; they were transferred to HFOV at a mean postnatal age of 30 hours. Their respiratory diagnoses included respiratory distress syndrome (RDS) (N = 19), neonatal 'adult respiratory distress syndrome' (ARDS) (N = 3) and meconium aspiration syndrome (MAS) (N = 12). Owing to similarities in the underlying pathophysiology, RDS and ARDS were grouped together for the purposes of analysis. After starting HFOV the a/APO2 had significantly improved (P < 0.05) by 6 hours in the RDS group and by 12 hours in the infants with MAS. This improvement was sustained throughout the first 48 hours of HFOV. Twenty-six (76%) of the infants ultimately survived. Among those who met the criteria for ECMO (N = 13), the survival rate was 92%. Air leaks occurred on HFOV in 6 infants, 3 each in the MAS and RDS groups. Bronchopulmonary dysplasia was diagnosed in 6 (40%) of the 15 RDS infants and in 2 (18%) of the 11 infants with MAS. Eight infants died, 3 following nosocomial sepsis (Pseudomonas sp.), 3 due to extensive air leaks, 1 due to irreversible shock (unproven sepsis), and 1 due to ARDS. At a median age of 13.5 months the neurological development of 11 (5%) of 17 infants was normal; in 3 (18%) it was suspect and in 3 abnormal. Conclusions. The study demonstrates that a high-pressure/volume approach to HFOV is an effective mode of rescue ventilation for infants who present with severe respiratory failure caused by a variety of lung conditions during the neonatal period.
- ItemAn infant who survived abortion and neonatal intensive care(Informa Healthcare, 2005-01) Clarke, P.; Smith, J.; Kelly, T.; Robinson, M. J.Termination of pregnancy is a common procedure worldwide. In the UK, termination is legal until the 24th week of pregnancy, and allowed throughout gestation in certain circumstances. Some infants aborted at the margins of viability (22 – 24 weeks’ gestation) show signs of life at delivery. We report an infant who survived abortion at approximately 23 weeks’ gestation and who survives long-term following many months of neonatal intensive care.
- ItemMagnetic resonance imaging of the cerebral malformation in Miller-Dieker syndrome. A case report(Health & Medical Publishing Group, 1988-12) Smith, J.; Schoeman, J. F.; Booysen, J. T.Absent or defective cortical gyri (lissencephaly) combined with a characteristic phenotypic appearance was first reported by Miller and Dieker in 1963 and the clinical, computed tomographic and pathological features of this syndrome have been extensively reviewed. We report on magnetic resonance imaging of the brain in a sporadic case of this syndrome.
- ItemThe necessity for T-cryptantigen activation screening in babies with necrotising enterocolitis(Health & Medical Publishing Group, 1996) Kirsten, G. F.; Smith, J.; Pieper, C.; Bird, A.; Wessels, G.; Riphagen, S.; Moore, S.Objective. To determine the prevalence of T-cryptantigen activation (TCA) and its predictive value for severity of necrotising enterocolitis (NEC) in babies. Study design. Prospective descriptive. Study population. Thirty-four babies with NEC were prospectively screened for TCA at Tygerberg Hospital over a 6-month period. TGA screening was done by testing for red blood cell agglutination by the common peanut lectin, Arachis hypogea. Once TCA was confirmed, only washed red cells were administered to the babies and plasma-containing blood products were avoided. NEC was divided into suspected NEC (stage 1), classic NEC (stage 2) and fulminant NEC (stage 3). Main outcome measures. Prevalence of TCA in babies with various stages of NEC; the association between TCA and bowel necrosis, need for surgery and mortality. Results. TCA was positive in 8 (24%) of the babies in this study. Six babies (18%) had stage 1 NEC, 10 (29%) had stage 2 NEC and 18 (53%) had fulminating or stage 3 NEC. All 18 babies with stage 3 NEC required surgery and TCA was present in 8 (47%) of them. Twelve babies (35%) died, 3 with TCA and 9 with no TCA. Babies with TCA had portal venous gas on abdominal radiographs (P = 0.037) and stage 3 NEC (P = 0.003) more often than babies with no TCA. Conclusions. A strong association was noted between TCA and the fulminant form of NEC with bower necrosis. TCA in a baby with NEC should alert the surgeon to the possibility of severe disease and the need to avoid plasma-containing blood products. Blood banks are urged to introduce routine screening for TCA in all babies with NEC.
- ItemNeonatal hypotension survey : a South African perspective(Health & Medical Publishing Group, 2019-06-25) Van Wyk, L.; Smith, J.; Hall, M.Background. Neonatal hypotension remains one of the most controversial topics in neonatology. Various definitions are used but lack an evidence base. Owing to the variation in defining a low blood pressure (BP), significant differences in pharmacological manipulation of BP are evident. Objectives. The aim of the present research was to determine the diagnostic criteria for neonatal hypotension and management strategies for neonatal hypotension in South Africa. Methods. A 29-point questionnaire was designed to determine the criteria used by South African neonatologists and paediatricians to diagnose and manage neonatal hypotension. The survey was conducted at two different time points in 2017. Results. The combination of the two surveys resulted in a 9.3% (47/507) response rate. A BP below the gestational age (in weeks) was the most common definition used for neonatal hypotension (75%). Most clinicians (86%) administered fluid prior to initiating inotrope therapy. Dopamine, dobutamine and adrenaline were the most common first-, second- and third-line anti-hypotensive drugs used. Most clinicians (77%) did not use a hypotension management guideline. Conclusion. Neonatal hypotension definition and management in South Africa are similar to international patterns, despite a lack of evidence to support the diagnosis and management strategies.
- ItemOnyalai - therapeutic effects of vincristine sulphate : a prospective randomized trial(Health & Medical Publishing Group, 1986-08) Hesseling, P. B.; Girdle-Brown, B.; Smith, J.Twenty out of 40 patients with onyalai admitted to Rundu State Hospital, Kavango, SWA/Namibia, were randomized to receive a vincristine sulphate bolus of 1,5 mg/m2 or an equivalent volume of normal saline intravenously on days 8 and 15 when haemorrhage or a platelet count of less than 50 x 109/l persisted for more than 1 week after admission. All patients were observed in hospital for at least 21 days. Five out of 10 patients who received vincristine achieved a platelet count in excess of 100 x 109/l on day 21 and only 2 out of 10 patients who received placebo achieved a similar rise in the platelet count. Two patients, neither of whom was treated with vincristine, died of cerebral haemorrhage.
- ItemPersistent pulmonary hypertension of the neonate in a developing country - does extracorporeal membrane oxygenation have a role to play?(Health & Medical Publishing Group, 1993) Smith, J.; Kirsten, G. F.A retrospective study was undertaken of survival after conventional management of 35 infants suffering from persistent pulmonary hypertension of the neonate (PPHN). The outcome of infants weighing more than 2000 g and who also qualified for extracorporeal membrane oxygenation (ECMO) therapy on the grounds of published criteria was assessed. The admission incidence of patients with PPHN was 1,1%. Secondary PPHN was more common than primary. The overall survival rate of 69% in this study reflects the trend in recently reported improved survival rates of infants with PPHN, treated with conventional techniques. Sixteen of 28 infants weighing more than 2000 g qualified for ECMO therapy; 4 of them died. Had ECMO been available as an alternative mode of therapy, only 2 of the 4 might have been saved. The other 2 were considered to have conditions incompatible with a normal quality of life. We therefore assessed the requirement for ECMO in our population to be approximately 0,6/1000 live births. Although ECMO may be promising, the introduction of this technique in developing countries should rather be delayed until more substantial data refute this. Because PPHN could be related to a potential preventable cause in almost 80% of cases, we propose the support of more cost-effective strategies such as continuing obstetric and perinatal education programmes.
- ItemPrevalence of and risk factors for retinopathy of prematurity in a cohort of preterm infants treated exclusively with non-invasive ventilation in the first week after birth(Health & Medical Publishing Group, 2013-01-14) Van der Merwe, S. K.; Freeman, N.; Bekker, A.; Harvey, J.; Smith, J.Objectives. To determine the current prevalence of retinopathy of prematurity (ROP) in premature babies treated with non-invasive ventilation at Tygerberg Children’s Hospital, Parow, Cape Town, South Africa, and to identify risk factors associated with the development of ROP. Methods. A retrospective medical records review of infants screened for ROP during a 2-year period (January 2009 - December 2010). Infants who did not receive invasive ventilation during the first week of life were included. Twenty-four previously reported risk factors for the development of ROP were identified for use in a multivariate logistic regression (MLR) analysis. Results. A total of 356 patients were included. The overall prevalence of ROP was 21.8% and that of clinically significant ROP (CSROP) 4.4%. The risk factors with a statistically significant association with the development of ROP on MLR analysis were severe apnoea (p=0.0005) and decreasing birth weight (p=0.0382). Conclusions. There is a low prevalence of ROP in the cohort of preterm infants treated exclusively with non-invasive ventilation in the first week of life. The risk factors of importance in our population were severe apnoea and lower birth weight. Birth weight is a practical and reproducible variable that can be used to aid development of ROP screening criteria.
- ItemThymic size at birth in preterm infants with severe respiratory distress syndrome can be used to predict the likelihood of survival : a retrospective cohort study(Health & Medical Publishing Group, 2010) Tooke, L. J.; Smith, J.; Griffith-Richards, S.; Maritz, J. S.Objective. To determine whether the thymic size in preterm infants with severe respiratory distress syndrome (RDS) canbe used to predict survival. We also set out to determine which antenatal and postnatal factors have an influence on, or correlation with, thymic size. Methods. A retrospective study was conducted on 55 consecutive preterm infants who were ventilated for RDS. A chest X-ray (CXR) was taken within the first 24 hours, and the cardiothymic/thoracic ratio (CT/T ratio) calculated. This ratio was then correlated with outcome, as well as antenatal maternal and postnatal factors. Results. Of the 49 infants included in the study (6 were excluded), 15 died and 34 survived. There was a statistically significant correlation between the CT/T ratio and survival (p=0.029). In those infants above 1 030 g, the CT/T ratio was more significant (p=0.038) than birth weight in predicting survival. The severity of RDS did not influence the CT/T ratio. The only maternal and postnatal factors influencing CT/T ratio were the presence of pre-eclamptic toxaemia (PET) and birth by caesarean section (CS), but these factors did not influence likelihood of survival. Factors found to be not associated with thymic size were antenatal steroid administration, maternal HIV status, clinical chorio-amnionitis, gender, gestational age (small or appropriate weight) and lymphocyte count. Conclusions. A small thymus measured in the first 24 hours can be used to predict likelihood of survival in infants weighing more than 1 030 g, but not in smaller infants. Prenatal stress associated with PET and indication for CS may cause the thymus to shrink.
- ItemTranscutaneous bilirubinometry versus total serum bilirubin measurement for newborns(John Wiley & Sons, Ltd. on behalf of The Cochrane Collaboration, 2017) Okwundu, C. I.; Uthman, O. A.; Suresh, G.; Smith, J.; Wiysonge, Charles S.; Bhutani, V. K.This is a protocol for a Cochrane Review (Diagnostic test accuracy). The objectives are as follows: - To determine the diagnostic accuracy of TcB as: i) a diagnostic test for hyperbilirubinaemia in newborns suspected to have hyperbilirubinaemia on visual inspection; ii) a diagnostic test for monitoring bilirubin levels in newborns receiving treatment (e.g. phototherapy) for hyperbilirubinaemia. - To determine whether the gestational age, postnatal age, body weight, race and site of TcB measurement have any influence on the accuracy of TcB measurement for hyperbilirubinaemia in newborns.
- ItemTranscutaneous screening for hyperbilirubinemia in neonates(Cochrane, 2014) Smith, J.; Uthman, O. A.; Okwundu, C. I.This is the protocol for a review and there is no abstract. The objectives are as follows: To evaluate to the effects of transcutaneous screening for hyperbilirubinemia to prevent the readmission of neonates for phototherapy.