Retinopathy of prematurity: screening and optimal use of the ophthalmologist's time

In recent years it has been standard practice to recommend that indirect ophthalmoscopy be carried out between six and nine weeks of age in very low birthweight infants to screen for the presence of retinopathy of prematurity (ROP). Following this recommendation we examined 85 infants over a two-year period. Acute ROP occurred in 29 (34%), and two (2.4%) developed cicatricial disease. One-third of infants were initially examined slightly earlier or later than the strict six to nine week limits, but all except three infants were examined between 35 and 42 weeks gestation. One infant born at 26 weeks gestation, was examined 'too late' in that she had stage 4 disease when first seen at 11 weeks of age. Recent information on the natural history of ROP, and confirmation of the efficacy of treatment with cyotherapy, suggested that the timing of an initial screening examination for ROP needed reassessment. From our experience and a review of the literature we recommended that infants of less than 1000 g birthweight or less than 28 weeks gestation have an initial examination at six weeks of age; for infants of 1000 to 1250 g birthweight or 28 to 30 weeks gestation examination continue to be at six to nine weeks of age; and for infants of more than 1250 g birthweight or 31 weeks gestation screening at six to nine weeks of age is only necessary if the infant has had an unstable course or prolonged oxygen requirements. Such a protocol would not place too great a burden on ophthalmological services and would direct efforts towards the group of infants most at risk of severe visual handicap.

Audit of drug usage in a regional neonatal intensive care unit

Drug utilization has been audited prospectively for all infants cared for in a regional neonatal intensive care unit for a 3-month period. Twenty-five infants had a birthweight less than 1500 g and 54 had a birthweight greater than 1500 g. The total number of different drugs used was 76 and the mean number received was 8.6 with a range of 0-30. Infants with birthweights less than 1500 g received a mean of 14.5 drugs and infants with birthweights greater than 1500 g received a mean of 4.8 drugs. Almost two-thirds (63%) of doses were given orally, 20% intravenously and 10% via an umbilical artery catheter. Three drugs, one of which was received by 13% of infants, carried manufacturers' inserts advising against use in premature infants or the newborn.

Transportation of very low birthweight infants in 1986

Details on transportation of all infants with a birthweight less than 1500 g born in 1986 have been recorded. Of 413 liveborn infants, 182 (42.3%) were involved in 256 transportations. Sixty-eight infants (16.5%) were transported from home or from a lesser to a more sophisticated neonatal unit within 48 hours of birth for neonatal intensive care. Twenty-five infants (6.1%), comprising 12 in utero (9 mothers) and 13 liveborn infants were transported out of their region because of a lack of intensive care spaces locally: 17 of these infants, including five born in National Women's Hospital, were Auckland and Northland infants (this representing 15% of regional very low birthweight infants). Hamilton received 12 infants from outside their region (14% of very low birthweight infants cared for). One hundred and fifty-three infants (45.1% of 339 surviving infants) were transported from one of the five regional neonatal intensive care centres to a smaller centre nearer home following recovery from intensive care. Most neonatal transportation is highly appropriate transfer within regions enabling scarce skills and resources to be concentrated in the regional centre and allowing infants to return nearer home when they are no longer sick. The number of very low birthweight infants coming to neonatal intensive care units increased dramatically in the decade prior to 1986 despite a fall in total New Zealand births. Now that the total births are increasing again the pressure on neonatal intensive care spaces is likely to increase further.

Transfusion-associated fall in platelet count in very low birthweight infants

Thirty-three infants with a birthweight of less than 1500 g were investigated retrospectively for the incidence and aetiology of thrombocytopenia occurring during the first week of life. The platelet count fell below 100 x 10(9)/l in 16 infants (48%). There was a moderately strong inverse correlation between the platelet count at its nadir during the first week or the first value below 100 x 10(9)/l and the percentage of blood volume transfused prior to this (r = -0.61; P less than 0.0001). When the platelet count was expressed as a percentage of the initial count the correlation was -0.74 (P less than 0.0001). The results were not affected by the elimination of the 10 infants with clinical conditions regarded as a probable cause of thrombocytopenia. The fitted least-squares regression line suggests that a transfusion equal to 10% of the blood volume on average reduced the platelet count by 19 x 10(9)/l or by 7% in these very low birthweight infants during the first week of life.

Incidence of retinopathy of prematurity in New Zealand

The incidence of retinopathy of prematurity has been prospectively assessed in very low birthweight infants born in one year in New Zealand. A total of 26 (11%) surviving infants with birth weight 1000-1499 g had acute retinopathy. Forty one (49%) surviving infants with birth weight 500-999 g had acute retinopathy and of these six (7%) became bilaterally totally blind.

Drugs in human milk. Clinical pharmacokinetic considerations

Drugs ingested by a lactating mother would be expected to appear in human milk to some extent and be ingested by a breast-feeding infant. Drugs pass from maternal plasma into milk by passive diffusion and are distributed within the aqueous, protein and lipid phases of milk. Distribution into milk will be affected by physiochemical characteristics of the drug: acid-base characteristics, relative protein binding in plasma and milk, and lipid solubility, as well as milk composition. The milk-to-plasma concentration ratio is the most commonly quoted index of drug distribution into human milk. However, calculation of the daily infant dose of drug ingested in milk, and from this the dose in milk relative to the maternal dose on a weight-adjusted basis, is a more relevant indicator of infant exposure to a drug. This is particularly true for drugs with a high volume of distribution, for which only a small proportion of the mother's dose is contained within the plasma and available for distribution into milk. A better indication of infant exposure to a drug is the steady-state plasma drug concentration in a breast-feeding infant, the major determinants of which are the dose rate (via milk) and the oral availability and clearance in the infant. Although in neonates the rate of absorption may be different from adults, there is little evidence that its extent is significantly different. Clearance, however, is impaired in very young infants, particularly if premature. The decreased clearance would result in a proportional increase in steady-state plasma concentrations in the breast-feeding infant. Consideration of the dose ingested in milk and the approximate clearance in infants of different ages allows estimation of likely steady-state plasma concentrations in breast-feeding infants. From these considerations, recommendations regarding the safety of drugs during breast-feeding can be made. Drugs which are very toxic or have dose-independent toxicity should be considered separately. Recommendations regarding 'social' drugs such as nicotine, alcohol, caffeine and theobromine are particularly difficult, as doses are uncontrolled and vary variable.

Inguinal hernia and low birthweight

Ten point three percent of infants of birthweight less than 2000 g developed an inguinal hernia within one to three years of birth. This figure rose to 18.9% in those who were under 1500 g at birth. The high requirement for surgical repair and the rising survival figures for very low birthweight infants stresses the increasing numbers at risk from postoperative apnoea and bradycardia. The need for respiratory and cardiac monitoring following anaesthesia in low birthweight infants is emphasised.

Epidemiology of insulin-dependent diabetes mellitus in Canterbury, New Zealand

A prospective study of incidence and prevalence of insulin-dependent diabetes mellitus in persons under 20 years was conducted over a 4-year period (1 February 1982-1 February 1986) for the Canterbury Hospital Board (total population 342,000) area in New Zealand. A central register for the area was established at the beginning of the study period. Degree of ascertainment was close to 100%. Average annual incidence was 11.7 persons per 100,000 (females: 10.6 per 100,000; males: 12.7 per 100,000) with no significant sex difference or temporal trends. Incidence peaks were seen for both sexes in the pubertal ages (females: 11 years; males: 13 years), with minor peaks occurring for both sexes in the pre-school ages. Age of onset was significantly younger in females than males. A seasonal variation in incidence was seen for males, with peaks in late autumn and mid-winter. 5.7% of the new diabetics had a first-degree relative with insulin-dependent diabetes mellitus. Islet cell cytoplasmic antibodies were detected in 68% of new diabetics and in 0% of age- and sex-matched healthy controls. Thyroid, gastric and adrenal auto-antibodies were seen more frequently in diabetics than in controls, but this difference was not significant. Prevalence of insulin-dependent diabetes on 1 February 1982 was 1.00 per 1000 and 1.05 per 1000 on 1 February 1986. The insulin-dependent diabetes mellitus incidence characteristics noted for the Canterbury Hospital Board area are similar to those reported for European and North American populations.

Retinopathy of prematurity: review of a five-year period, examination techniques and recommendations for screening

The reported resurgence of retinopathy of prematurity prompted analysis of the prevalence of retinopathy among premature infants born at Christchurch Women's Hospital over a five-year period. Of the 129 surviving very-low-birthweight infants, 65 (50.4%) underwent ocular screening during the review period. Retinopathy was detected in 17.1% (22/129) of surviving infants, or 34% (22/65) of selected infants referred by paediatricians for ocular screening. Five infants had severe or blinding retinopathy and these premature infants were of significantly lower birthweight and born after shorter gestation periods than those found to have no retinopathy. Examination techniques for eyes of premature infants are discussed, and recommendations for screening for retinopathy of prematurity made.

Neurodevelopmental outcome for infants of very low birthweight admitted to a regional neonatal unit, 1979-1983

From January 1979 to December 1983, 178 infants with birthweight 501-1500 g were admitted to the neonatal unit at Christchurch Women's Hospital. One hundred and twenty-nine (72.5%) survived to discharge from the unit. Six infants died post discharge by 12 months of age. Fifty-six percent of surviving infants for whom records were available were admitted to hospital in the first year of life. Thirty infants could not be traced for follow-up. Ninety-three infants were assessed for functional abnormalities utilising medical records, neurological examination and developmental assessment. Thirteen infants (14%) had handicap: 7 (7.5%) with mild or moderate and 6 (6.5%) with major dysfunction. It is essential that neonatologists know the long term outcome for their neonatal intensive care practices and provision must be made for comprehensive follow-up of surviving very low birthweight infants.

Handling during neonatal intensive care

The handling received by very low birthweight newborns undergoing intensive care in the first few days of life and the effects of this were studied. Infants were handled an average of 4.3 hours (18%) of the total 24 hour observation time and received a mean 234 handling procedures. Parental handling contributed 35% of the total time but was usually benign except in that it could interfere with the infant's rest. Many procedures were associated with undesirable consequences. Endotracheal suctioning was invariably associated with hypoxaemia and was often carried out more frequently, or took longer, than was optimal. Transcutaneous oxygen monitoring, although considered routine for all intensive care infants, was only carried out for 50% of the observation time and often did not accompany periods of likely intensive handling. Increasing technology in neonatal intensive care often results in increased handling of sick infants. Each new innovation, as well as routine procedures, should be viewed in the light of the continuum of neonatal intensive care events, and handling kept to a minimum.

Bone marrow transplantation for severe aplastic anaemia

An eight-year-old girl with severe acquired aplastic anaemia received a bone marrow transplant from her 11-year-old brother. The bone marrow graft is firmly established, but the patient has mild chronic graft versus host disease affecting liver and skin. The indications for bone marrow transplantation in aplastic anaemia are discussed.

Multiple myeloma--prognosis, treatment and survival in an eight year study

Data are presented from an unselected group of 76 patients with multiple myeloma, diagnosed over an eight year period in Christchurch. The median survival time was 31 months from commencement of treatment. The median survival of patients with Bence Jones proteinuria (29 months) was significantly shorter than those without this feature (47 months). Patients with lambda proteinuria had a median survival of 25.5 months and those with kappa proteinuria 32 months, but this difference was not statistically significant. The correlation of presenting anaemia, azotaemia or hypoalbuminaemia with a bad prognosis was confirmed. Immunosuppression of nonmyeloma immunoglobulins in patients with IgA or IgG myeloma was associated with a significantly worse median survival. Chemotherapy was discontinued in 11 patients at a variable period after one year of remission. In six cases the disease did not relapse, but relapse occurred in four cases and in three of these control could not be reasserted. One patient developed acute myeloblastic leukaemia five months after treatment was discontinued.

Symptomatic hyponatraemia associated with tolbutamide therapy

A case of hyponatraemic coma occurring in a patient with diabetes mellitus treated with tolbutamide is described. Although chlorpropamide is known to cause water retention in some circumstances, this is a less well recognized complication of tolbutamide therapy.