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Biomedical subjects

N Rutter

Publications and source records attributed to N Rutter.

At least 37 records · Page 2Linked to original sources
PubMed1996

Stress, severity of illness, and outcome in ventilated preterm infants.

AIM: To determine physiological and hormonal stress responses in ventilated preterm infants. METHODS: Physiological and hormonal stress responses were studied in 47 ventilated preterm infants who were judged clinically to require sedation. The correlation between the stress response and severity of illness was examined, and responses were compared between infants with different clinical outcomes. RESULTS: Stress hormone concentrations were significantly correlated with severity of illness, assessed using the arterial: alveolar oxygen partial pressure ratio. Noradrenaline showed the strongest correlation, with an exponential pattern of increased secretion. Catecholamine concentrations before sedation were significantly higher among infants who subsequently died (n = 15, at a median age of 6 days) than among survivors: median noradrenaline 4.31 vs 2.16 nmol/l, median adrenaline 0.69 vs 0.31 nmol/l. The observed fall in noradrenaline with sedation was lower among those who died than survivors (median fall 2% vs 40%). CONCLUSION: Preterm infants are capable of hormonal stress responses appropriate for the severity of their illness. Extreme catecholamine responses, in the sickest infants, are associated with the worst outcome.

Epinephrine↗
PubMed1995

Neonatal hypertension and cardiac failure.

Two newborn infants developed cardiac failure due to severe hypertension which was recognised as the heart failure was treated. Renal abnormalities were found in both infants who are normotensive off treatment at 18 months follow up. The finding of hypertension rather than hypotension in the presence of cardiac failure and the apparent absence of a cardiac abnormality should prompt a search for a renal or renovascular cause.

Female↗
PubMed1995

Exposure to invasive procedures in neonatal intensive care unit admissions.

The nature and numbers of invasive procedures were studied in 54 consecutive infants admitted to a neonatal intensive care unit. Over 3000 procedures were recorded, 74% in infants below 31 weeks of gestation. One infant (23 weeks' gestation, birth weight 560 g) underwent 488 procedures. Heel prick blood sampling was the most common procedure (56%), followed by endotracheal suction (26%) and intravenous cannula insertion (8%). Invasive procedures which would cause pain or distress to a child are frequently performed on infants admitted to the neonatal intensive care unit. A reduction in the number of procedures, modifying them, or providing adequate analgesia could relieve some of this pain and distress.

Blood Specimen Collection↗
PubMed1995

Lignocaine ointment and local anaesthesia in preterm infants.

The ability of topically applied lignocaine ointment to produce surface anaesthesia was examined in 45 preterm infants (gestational age 25 to 35 weeks) at a median age of 2 days. Two strengths of ointment, 5% and 30%, were tested at 30 and 60 minutes after application to the dorsum of the foot. Anaesthesia was assessed by comparing the response to skin stimulation at the test and control sites, using von Frey hairs. In 84% of cases responses indicated that there was no surface anaesthesia. Topically applied lignocaine ointment is not an effective local anaesthetic in preterm infants, presumably due to poor absorption.

Administration, Topical↗
PubMed1995

Randomised, double blind trial of two loading dose regimens of diamorphine in ventilated newborn infants.

AIMS: To compare the safety and efficacy of two loading doses of diamorphine in 27 ventilated newborn infants in a randomised double blind trial. METHODS: Fifty or 200 mcg/kg were infused intravenously over 30 minutes, followed by a 15 mcg/kg/hour continuous infusion. Serial measurements were made of physiology, behaviour, and stress hormones. RESULTS: Both loading doses produced small but significant falls in blood pressure. The 200 mcg/kg dose produced greater respiratory depression, and two infants deteriorated clinically, requiring resuscitation. Loading reduced respiratory effort in most of the infants, but had little effect on behavioural activity. Stress hormone concentrations were reduced at six hours in both dosage groups; differences between loading doses were not significant. Morphine, morphine-3-glucuronide, and morphine-6-glucuronide were detected in the plasma of all patients. No significant differences in concentrations between loading doses were found. CONCLUSIONS: Diamorphine reduces the stress response in ventilated newborn infants. A high loading dose confers no benefit, and may produce undesirable physiological effects. A 50 mcg/kg loading dose seems to be safe and effective.

Analgesics, Opioid↗
PubMed1994

Percutaneous lignocaine absorption in newborn infants.

The permeability of the skin of newborn infants to lignocaine was examined in vitro using excised skin. Samples were studied from 24 infants of gestational age 25 to 40 weeks and postnatal age 0 to 7 days. Mature skin was relatively impermeable to lignocaine, but the more premature infants showed a marked increase in absorption. There was a strong inverse correlation between gestational age and skin permeability. These findings suggest that topical lignocaine would be an effective local anaesthetic in preterm infants. Calculations indicate that there is negligible risk of toxicity due to systemic absorption.

Anesthetics, Local↗
PubMed1994

Heel blood sampling in preterm infants: which technique?

Preterm infants undergoing heel blood sampling were randomly allocated to specimen collection by heel puncture (Autolet II Clinisafe) or incision (Tenderfoot 'preemie'). A total of 187 procedures was observed in 47 infants. No significant difference was found in the infants' behavioural response, increase in heart rate, or in the frequency of specimen haemolysis. Collection times for small to medium sized samples were similar, but for large samples (> 1 ml) the Tenderfoot method was superior and fewer repeat procedures were necessary. Tenderfoot has the added advantage of improved safety, but it is too costly for routine use.

Blood Specimen Collection↗
PubMed1994

Transdermal delivery and the premature neonate.

Drugs can penetrate more readily through the skin of preterm neonates compared to adults. This observation suggests that transdermal drug delivery may offer advantages compared with the traditional intravenous or oral routes of drug administration used in neonatal intensive care. The transdermal route of drug delivery is potentially a convenient, painless, and noninvasive method of drug therapy without the difficulties, discomfort, and scope for error of intravenous or oral administration. Successful transdermal therapy in the neonate has been achieved with the drugs theophylline and caffeine, with therapeutic blood drug concentrations being achieved for up to 7 days after topical application. Several other drugs in common use in neonatal intensive care therapy have good potential for transdermal delivery. However, there is a need for further development of neonatal transdermal delivery systems to provide a controlled rate of drug delivery.

Administration, Cutaneous↗
PubMed1993

An in vitro study of diamorphine permeation through premature human neonatal skin.

The permeation kinetics of diamorphine through human premature neonatal cadaver skin over a range of gestational ages between 24 and 36 weeks was investigated using small diffusion cells. A strong inverse correlation was noted between the apparent permeability coefficient and the gestational age of the skin (P < 0.01; n = 26). The calculated apparent permeability coefficients decreased with gestational age from 6.0 x 10(-2) cm.hr-1 at 24 weeks' gestation to 5.2 x 10(-6) cm.hr-1 at 36 weeks' gestation. The amount of diamorphine remaining bound within the skin at the end of the in vitro experiments did not change significantly with gestational age of the skin. Diamorphine was subject to degradation over the course of the in vitro experiments to produce significant amounts of 6-monoacetylmorphine and evidence is presented to suggest that this was due to residual skin esterase activity. It is calculated that the steady-state flux rate of diamorphine through neonatal skin observed in these experiments would be sufficient to obtain a therapeutic plasma concentration of morphine assuming a 2-cm2 area for application and a delivery rate of 15 micrograms hr-1 kg-1. However, the prolonged half-life of morphine in the premature neonate would result in a delay of some hours before the attainment of this level.

Chromatography, High Pressure Liquid↗
PubMed1993

The pharmacokinetics and physiological effects of buprenorphine infusion in premature neonates.

1. The pharmacokinetics and physiological effects of buprenorphine were studied in 12 newborn premature neonates (27 to 32 weeks gestational age) who were given a loading dose of 3.0 micrograms kg-1 of buprenorphine followed by an intravenous infusion of 0.72 micrograms kg-1 h-1 of buprenorphine. Plasma concentrations of buprenorphine were measured during the infusion, at steady-state and for 24 h after the cessation of the buprenorphine infusion. 2. The mean steady-state plasma buprenorphine concentration (+/- s.d.) for an infusion rate of 0.72 micrograms kg-1 h-1 was 4.3 +/- 2.6 ng ml-1. 3. Buprenorphine clearance was 0.23 +/- 0.07 l h-1 kg-1, the elimination half-life was 20 +/- 8 h and the volume of distribution was 6.2 +/- 2.11 l kg-1. 4. Small but significant falls were noted in systolic blood pressure at 6 h and heart rate at 1, 6 and 12 h after the administration of buprenorphine, but these did not appear to cause any clinical deterioration. 5. Four of the 12 subjects studied required an increase in the infusion rate of buprenorphine to achieve adequate sedation. 6. The results suggest that this dosing regimen of buprenorphine is safe but may not be as effective as other opioids in producing sedation and analgesia in premature newborns.

Analgesics, Opioid↗
PubMed1993

Do preterm infants always have flattened heads?

It has previously been shown that a soft mattress lessens the degree of head flattening that occurs in preterm infants in the early weeks of life. A follow up study of 31 infants of < 32 weeks' gestation found head flattening had resolved by 3-4 years of age, regardless of the type of mattress used in the neonatal period, and the children had heads similar in shape to full term controls.

Age Factors↗
PubMed1993

Sex linked valvular dysplasia.

A family is described in which three males have been affected by congenital valvular dysplasia of one or more heart valves, in one case leading to neonatal death. The pedigree is consistent with sex linked inheritance.

Adult↗
PubMed1991

Morphine kinetics after diamorphine infusion in premature neonates.

1. The pharmacokinetics of morphine were studied in 26 newborn premature neonates (26-38 weeks gestational age) who were given a loading dose of 50 micrograms kg-1 of diamorphine followed by an intravenous infusion of 15 micrograms kg-1 h-1 of diamorphine. Plasma concentrations of morphine were measured during the infusion at steady-state and for 24 h after the cessation of the diamorphine infusion. 2. The mean steady-state plasma morphine concentration (+/- s.d.) for a diamorphine infusion rate of 15 micrograms kg-1 h-1 was 62.5 +/- 22.8 ng ml-1. 3. Morphine clearance was 3.6 +/- 0.9 ml min-1 kg-1, the elimination half-life was 8.9 +/- 3.3 h and the volume of distribution was 2.7 +/- 1.01 kg-1. 4. Morphine elimination kinetics were described by a mono-exponential function. 5. There was a direct relationship between the gestational age of the patients and the clearance (r2 = 0.31, P = 0.003) and half-life (r2 = 0.35, P = 0.01) of morphine, but no relationship was found between gestational age and volume of distribution. 6. The results suggest that the currently used dosing regimen of diamorphine achieves a safe and effective morphine concentration in the premature newborn but that the loading dose could be modified to achieve a more rapid onset of analgesia.

Birth Weight↗