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Biomedical subjects

R Hawker

Publications and source records attributed to R Hawker.

16 recordsLinked to original sources

Surgical programme at Royal Alexandra Hospital, Sydney, for Papua New Guinea children with congenital heart disease, 1978-1994.

OBJECTIVE: To report the history of the Royal Alexandra Hospital for Children (RAHC) Papua New Guinea (PNG) cardiac surgical programme and describe the selection, preoperative clinical features and postoperative outcome of children with congenital heart disease managed by the programme. METHODS: Details for each of the PNG cardiac patients admitted to RAHC following selection by visiting cardiologists between 1978 and 1994 were entered into a database, and analysed and interpreted. RESULTS: A congenital heart defect was confirmed in 165 of the 170 children selected. The male to female ratio was 1:1 and the mean age on admission to RAHC was 5.5 years. Almost all of the children for whom data were available (98%) had a weight for age and 41% had a height for age less than the 3rd centile. One-sixth had delayed milestones. A large number were tachypnoeic, in heart failure, or had pulmonary hypertension on admission. Ventricular septal defect and tetralogy of Fallot were the commonest defects, and lesions such as aortic stenosis, coarctation of the aorta and transposition of the great arteries were absent or rare. Thirty-one (19%) of the children selected initially did not receive surgery because of pulmonary hypertension, or because the lesions did not fall within the programme guidelines for operation. One hundred and twenty-nine children had corrective and four had palliative procedures. Half of the operated children had postoperative complications. Eight children died, all following open-heart procedures, giving a case fatality rate of 6%. Preoperative tachypnoea, hepatomegaly, cardiac failure and pulmonary hypertension were strongly associated with poor outcome. CONCLUSIONS: The programme was an arduous exercise for all organizations concerned, but achieved comparatively good short-term outcomes. The experience gained should assist in planning for similar programmes.

Adolescent↗

Congenital heart disease in Papua New Guinean children.

The aim of the study was to analyse critically the programme for surgical management of children in Papua New Guinea (PNG) with congenital heart disease. A hospital record-based analysis was undertaken to document the pattern, management and short-term outcome of surgery in PNG children referred with a diagnosis of congenital heart disease to the Royal Alexandra Hospital for Children in Sydney, Australia. On admission, physical examination, chest radiogram, electrocardiogram, cross-sectional echocardiogram and, in most cases, cardiac catheterization were performed. Of the 170 children referred over the 17-year period, 1978-1994, 165 were confirmed to have congenital heart disease and were included in the study. Their ages ranged from 2 months to 16 years (median 5.5) and the male to female ratio was 1:1. One-sixth had delayed milestones and one-fifth long-term wasting. A large number were tachypnoeic, in heart failure or had pulmonary hypertension on admission. Ventricular septal defect, 34%, tetralogy of Fallot, 23%, and patent ductus arteriosus, 16.4%, were the predominant defects. lesions such as aortic stenosis, coarctation of the aorta and transposition of the great arteries are under-represented. Altogether, 133 children (81%) had surgery; 75% were open- and 25% closed-heart operations. The complications were unremarkable and the mortality rate (6%) acceptable for the era. The programme was therefore very successful for a small proportion of children born in PNG with congenital heart disease.

Adolescent↗

The long-term stability of reconstituted exametazime: a clinical and laboratory evaluation.

99Tcm-exametazime has become recognized as an effective agent for in vitro leucocyte labelling. However, the material is relatively expensive and exhibits instability, being recommended for use within 30 min. Following subdivision and low-temperature storage of unlabelled exametazime we have evaluated long-term stability in a clinical setting and provided some laboratory support for the observations. Vials of exametazime were reconstituted with sodium chloride injection BP and subdivided into three aliquots prior to storage at -66 degrees C. At intervals up to 27 days they were used for routine leucocyte labelling with percentage labelling efficiency being recorded. Additional aliquots were tested for lipophilic primary complex and radiochemical impurities using thin layer chromatography over a similar period. Results on 92 patients gave a mean leucocyte labelling efficiency of 37% (range 10-78%). Chromatography supported the patient data. The percentage of primary exametazime remaining after 24 days' storage (55%) compared favourably with that in a freshly prepared aliquot, subdispensed but not stored (66%). Subdivision and refrigerated storage of unlabelled exametazime at -66 degrees C appears to preserve its radiolabelling capacity and the ability of the 99Tcm-exametazime to label leucocytes. This combination of long-term stability and improved cost-effectiveness may promote more widespread utilization of this pharmaceutical in clinical nuclear medicine.

Drug Stability↗

Late results of right ventricular outflow tract reconstruction with Björk-Shiley valved conduits.

Between 1971 and December 1976, 27 children with congenital heart disease underwent right ventricular outflow tract reconstruction with conduits incorporating a Björk-Shiley valve. The conditions corrected were pulmonary atresia with ventricular septal defect (14 patients), truncus arteriosus (6 patients), and complex disease (7 patients). At operation the children were aged from 12 days to 16 years (five patients were less than one year old). Overall mortality for the group was high (52%). There were nine early deaths and five late ones. Actuarial survival till death or reoperation was 55% at four years, 35% at eight years, and 28% at 12 years. Ten children subsequently underwent reoperation for conduit stenosis caused by neointimal proliferation and valve obstruction. The new conduits incorporated a biological valve. Mortality was highest in patients aged less than one year, and in those with truncus arteriosus, severe pulmonary hypertension, or complex heart disease. Mechanical valves should be avoided in conduit reconstruction of the right ventricular outflow tract for congenital heart disease.

Adolescent↗

Size of spleen rather than amount of platelet sequestration may determine long term responses to splenectomy in adult idiopathic thrombocytopenic purpura.

Fourteen adults with idiopathic thrombocytopenic purpura suffered a relapse after treatment with steroids, vinca alkaloids, or intravenous gammaglobulin. Splenic sequestration of platelets labelled with 111In-oxine was assessed, and the patients then underwent splenectomy. During follow up of four to 47 months (mean 20.7) none of the patients required further treatment, including three of 14 who showed partial relapses. Splenic sequestration patterns did not predict relapses, but an unexpected finding was that patients who relapsed had significantly smaller spleens. It is concluded that splenectomy is beneficial in most adult patients with idiopathic thrombocytopenic purpura and that radiological techniques to measure the size of the spleen may be useful in predicting which patients may relapse.

Adolescent↗

Branch pulmonary artery growth after blalock-taussig shunts in tetralogy of fallot and pulmonary atresia with ventricular septal defect: a retrospective, echocardiographic study.

We performed a retrospective echocardiographic study in tetralogy of Fallot (TOF) or pulmonay atresia with ventricular septal defect (PA&VSD) to evaluate the effects of Blalock-Taussig shunt on branch pulmonary artery growth. There were 35 patients with TOF and 11 with PA&VSD. We measured the right and left pulmonary artery area index and also the combined pulmonary artery area index, both before and after shunt operation. The mean +/- SD of these three variables before the shunt operation in the TOF group were 63.5 +/- 22.5, 57.8 +/- 24.9, and 121.4 +/- 42.8 mm(2)/m(2); after shunt operation they were 98.5 +/- 33.6, 85.9 +/- 31.9, and 184.0 +/- 59.8 mm(2)/m(2), respectively (p values <0.0001, <0.0002, and <0.0001, respectively). In the PA&VSD group the comparable values before shunt operation were 66.5 +/- 16.0, 55.4 +/- 10.6, and 120.9 +/- 26.9 mm(2)/m(2) and after shunt operation were 90.5 +/- 22.9, 77.2 +/- 24.1, and 166.6 +/- 44.4 mm(2)/m(2), respectively (p values <0.0006, <0.014, and <0. 002, respectively). We also examined the effect of distensibility of pulmonary arteries by comparing the percentage change in size of the combined pulmonary artery area index in the first 4 months after shunt with those after this time (p < 0.023). There were no significant differences between left- and right-sided shunts, origin and distal pulmonary artery growth, and the TOF and PA&VSD groups.

Echocardiography↗

A history of surgery for congenital heart disease in Papua New Guinea.

Cardiothoracic surgery in Papua New Guinea (PNG) was somewhat ad hoc prior to 1956 but later settled into an arrangement in which visiting teams from overseas selected mostly adult patients for a limited range of closed heart operations to be done locally or overseas. In 1978 the late Professor John Biddulph was instrumental in facilitating a more formal arrangement with the Royal Prince Alfred Hospital whereby patients were selected by a visiting cardiologist on an annual basis to be transferred to Sydney for cardiac surgery. This subsequently developed into a predominantly paediatric program based at the Royal Alexandra Hospital for Children in Sydney, which successfully ran until 1992. In 1993 a program began, based at the Sydney Adventist Hospital, in which a voluntary cardiac team has been visiting annually to perform both open and closed heart surgery. This program has proved to be very successful with a high output and a low mortality. Despite this long history of surgery for congenital heart disease in PNG, no definite long-term plans have eventuated. Because the financial situation of the country does not allow for a major cardiothoracic unit, the current arrangement whereby noninvasive investigation and some closed surgery are performed at Port Moresby General Hospital is appropriate for the foreseeable future.

Australia↗