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Biomedical subjects

N McIntosh

Publications and source records attributed to N McIntosh.

At least 55 records · Page 3Linked to original sources

Practical approach to analgesia and sedation in the neonatal intensive care unit.

The anatomic and physiological bases for nociception are present even in very preterm neonates. Neonates show the same behavioral, endocrine, and metabolic responses to noxious stimuli as older subjects. Preterm infants appear to be more sensitive to painful stimuli and have heightened responses to successive stimuli. Infants receiving intensive care are subjected to frequent stressful procedures and also chronic noxious influences related to the environment of care. Inflammatory conditions such as necrotizing enterocolitis may also cause pain. Untreated pain in babies is associated with increased major morbidity and mortality. Nonpharmacological interventions, including environmental modification and comforting during procedures reduce stress. Intravenous opiates are the mainstay of pharmacological analgesia. A pure sedative agent can provide physiological stability in settings in which there are less acutely painful stimuli or when there are adverse effects from, or tolerance to, opiates. Local anesthesia of skin and mucous membranes is helpful for invasive procedures. Antipyretic analgesics such as acetaminophen have a role in inflammatory pain.

Analgesia↗

Port site metastasis from synchronous primaries of the colon and ovary following laparoscopic cholecystectomy.

We report two cases of port site metastasis as the presenting feature of colonic and ovarian carcinoma after laparoscopic cholecystectomy. Cholecystectomy was performed for upper abdominal pain and gallstones. Six and 4 months after the operation the patients presented with nodules at port sites, other than the site of extraction. Biopsy proved both to be adenocarcinoma and further management found these to be from advanced caecal and ovarian carcinomas.

Abdominal Muscles↗

The systemic stress response to thermal injury in children.

OBJECTIVE: Thermal injury is extremely stressful, but data characterizing the endocrine stress response to this injury in children are sparse. The objective of this study was to measure the effects of thermal injury on the levels of stress hormones in children and to assess the temporal changes associated with them. PATIENTS: Twenty-three children, 13 girls and 10 boys aged between 5 months and 12 years 3 months (mean, 2 years 11 months), with burns covering 10-61% of their body surface (mean, 20.5%) were studied during the first 5 days following injury. MEASUREMENTS: The levels of arginine vasopressin, angiotensin II, cortisol, adrenaline, noradrenaline and dopamine were measured in sequential blood samples obtained from thermally injured children on admission and at specified time intervals during the 5 days of the investigation. RESULTS: At admission the concentrations of all the hormones were high, and varied widely between individual patients. The geometric mean and 95% confidence intervals of admission hormone levels were as follows: arginine vasopressin 18.3 (8.3-40.7) pmol/l; angiotensin II 122.0 (56.0-266.2) pmol/l; cortisol 650.6 (473.0-895.0) nmol/l; dopamine 1.0 (0.1-8.0) nmol/l; adrenaline 6.4 (3.2-12.5) nmol/l and noradrenaline 2.3 (1.3-4.3) nmol/l. Although the concentrations of arginine vasopressin and cortisol returned to normal 24 to 36 h after admission, the levels of angiotensin II, adrenaline and dopamine fluctuated and remained higher than normal throughout the study (108 h). CONCLUSIONS: Thermal injury results in the release of abnormally high levels of stress hormones in children. Although there are similarities between some of the data reported here and those reported in adults, higher levels of adrenaline and lower levels of noradrenaline than reported in adults suggest important differences too. These differences may need to be taken into account in the management of burn-injured children.

Angiotensin II↗

A randomized, controlled trial of computerized physiologic trend monitoring in an intensive care unit.

OBJECTIVE: To assess whether the provision of computerized physiologic trend data could improve outcome in newborn infants requiring intensive care. DESIGN: Randomized, controlled trial, with subsidiary questionnaire studies. SETTING: Tertiary neonatal intensive care unit with 12 intensive care cots. PATIENTS: All infants admitted between January 1991 and September 1993 who were < or =32 wks gestation or >32 wks gestation, and ventilated for >4 hrs or asphyxiated. INTERVENTIONS: Randomization to one of four groups for first 7 days of life: A) no display of trend data; B) continuous display of trend data; C1) alternating 24-hr display of trend data, starting with display in first 24 hrs; and C2) alternating 24-hr display of trend data, starting with no display in first 24 hrs. MEASUREMENTS AND MAIN RESULTS: The short-term effects of monitoring on patient outcome was judged by volume of colloid given, number of blood gases taken, and by measurement taken from cranial Doppler ultrasound. Medium-term measures included time ventilated, time given supplemental oxygen, death, time to death or discharge, and cranial ultrasound at discharge. Long-term outcome was assessed by neurodevelopmental status at age 1 to 4 yrs of age. Staff and parent questionnaires assessed their respective attitudes to the introduction of this technology. None of the patient outcome measures, short-, medium-, or long-term, demonstrated any significant benefit from the provision of computerized physiologic trend monitoring. Staff questionnaires demonstrated an acceptance of the system and an improved understanding of neonatal physiology as a result of computerized physiologic trends. Parent questionnaires demonstrated increased anxiety caused by the system in 11% of parents, although only 1% of parents continued to have concerns if the system were able to help their child. CONCLUSIONS: A randomized, controlled trial was unable to demonstrate any benefit to patients resulting from the introduction of a computerized physiologic trend monitoring system. Benefits of the system have been recognized, however, in subsidiary studies, staff education, and research studies.

Attitude of Health Personnel↗

Randomised trial of erythromycin on the development of chronic lung disease in preterm infants.

AIMS: To determine if erythromycin given from birth reduces the inflammatory response and the incidence and severity of chronic lung disease. METHODS: Seventy five infants less than 30 weeks of gestation and ventilated from birth for lung disease were randomly assigned to receive erythromycin intravenously for 7 days or to no treatment. Ureaplasma urealyticum was detected in tracheal secretions by culture and polymerase chain reaction. Differential cell counts were obtained from bronchoalveolar lavage fluid collected daily for 5 days and concentrations of the cytokines interleukins IL-1 beta and IL-8, and tumour necrosis factor alpha (TNF-alpha) were measured. Chronic lung disease (CLD) was defined as oxygen dependency at 36 weeks of gestation. RESULTS: Nine infants (13%) were positive for U urealyticum. The inflammatory cytokines in the lungs increased over the first 5 days of life in all babies, but no association was found between their concentrations and the development of CLD. Those treated with erythromycin showed no significant differences from the non-treated group in the differential cell counts or concentrations of the cytokines. The two groups had a similar incidence of CLD. Babies infected with U urealyticum did not have a more pronounced cytokine response than those without infection. Chorioamnionitis was associated with significantly higher concentrations of IL-1 beta and IL-8 on admission: these babies had less severe acute lung disease and developed significantly less CLD. CONCLUSIONS: U urealyticum in the trachea was not associated with an increased inflammatory response in preterm infants. Erythromycin did not reduce the incidence or severity of CLD.

Anti-Bacterial Agents↗

Pain in the newborn, a possible new starting point.

Pain is not a subjective experience, it is, particularly in children, an emotional issue. The formation of the International Association for the Study of Pain (IASP) in 1973 injected some standards and objectivity into the subject which allowed investigators around the world to probe both the underlying scientific basis of pain and nociception (nociception being the noxious sensation per se with no regard to the emotional experience). At the same time therapeutic strategies for different clinical problems have been evaluated, putting pain management on a scientifically secure and more individually effective basis. Self report has been the 'gold standard' of pain measurement but even in co-operative adults this has inherent weaknesses/biases related to the person and their situation (both the feelings and the reporting of pain are context sensitive). In some clinical areas, subject report is clearly impossible e.g. the psychogeriatric population, the mentally retarded and in preverbal children. However, even in these groups, there are usually behavioural responses to acute pain that are reasonably interpretable by their caregivers.

Adult↗

The bigger the burn, the greater the stress.

Data characterizing the endocrine stress response to burn injury in children are sparse. We have measured the levels of the stress hormones arginine vasopressin, catecholamines-adrenaline, noradrenaline and dopamine-atrial natriuretic peptide and hormones of the renin-angiotensin-aldosterone system in admission blood samples taken from 35 children admitted to the burns unit of the regional children's hospital. Hormone levels were compared with the size of burn injury. With the exception of adrenaline, there were significant positive correlations between vasopressin (r = 0.707, p < 0.0001), plasma renin activity (r = 0.721, P < 0.0001), angiotensin II (r = 0.512, P = 0.002), aldosterone (r = 0.620, P < 0.0001), noradrenaline (r = 0.430, P = 0.0189), dopamine (r = 0.627, P = 0.0024) and percentage burn surface area, and a negative correlation between atrial natriuretic peptide (r = 0.548, P = 0.0008) and burn surface area. It is concluded that the hormones which react to stress are very sensitive to burn injury in children, and that the magnitude of their response is closely related to the size of the burn surface area.

Arginine Vasopressin↗

What is core? Guidelines for the core curriculum in paediatrics.

A key point that the UK General Medical Council addressed in its recommendations on the undergraduate medical education was the concept of 'core curriculum' (General Medical Council 1993). Although enthusiastic for the idea of reducing factual overload, many medical teachers found themselves facing the task of how to define what a core curriculum is, what should be included and why. Predictably, our initial response is to include common and important topics, but how common is common, and how does one determine the relative importance of topics? We do not claim to have unravelled all the ambiguities surrounding the subject nor to have resolved all the controversies that are inevitably encountered. We hope, however, to describe some of the principles that governed our approach and put forward some guidelines, that may contribute to the debate.

Child↗

Comparison of two different pulse oximeters in monitoring preterm infants.

OBJECTIVE: The aim of the study was to test the reliability and variation in the readings of two widely used pulse oximeters in preterm infants. DESIGN: Two different pulse oximeters and a transcutaneous PO2 monitor were used to record the data continuously on a cotside computer database. PATIENTS: Sixteen preterm infants were studied in the Neonatal Unit, Simpson Memorial Maternity Pavilion, Edinburgh, UK. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Approximately one fifth of the time, the pulse oximeter readings could be established as artifactual. Study of the remaining four fifths of the data showed that, on average, the Nellcor pulse oximeter recorded saturation percentages 2.2% higher than the Ohmeda oximeter. CONCLUSIONS: We recommend that all neonatal units adopt a policy of using different saturation alarm limits for these two instruments. We further recommend that other pulse oximeters be tested by a methodology similar to the one we present in this paper, before their use in monitoring oxygenation in preterm infants.

Equipment Design↗

Temperature control in very low birthweight infants during first five days of life.

AIM: To determine ranges for skin temperatures in infants weighing under 1000 g in the first five days of life. METHOD: Abdominal skin and foot temperatures were automatically collected each second, averaged over 1 minute and stored on computer. A computer program analysed the data in 83 babies weighing under 1000 g at birth over the first five days of life and expressed the temperatures as means and standard deviation. The temperature patterns seen in these babies were also visually analysed. The relation between an increasing abdominal skin-foot temperature difference and other signs of hypovolaemia was also studied. RESULTS: These babies all had similar temperature patterns. Just after birth there was little ability to vasoconstrict in the presence of cold stress and the babies behaved more like poikilothermic animals. Vasomotor tone developed in the first three days, resulting in a stabilisation of the abdominal skin temperature to a mean of 36.9 degrees C and a widening of the central-peripheral temperature difference (Td) to a mean of 1.0 degree C. A Td of > 2 degrees C was associated with other evidence of hypovolaemia for only 11% of the time. CONCLUSIONS: Infants weighing under 1000 g have poor vasomotor control at birth and are at increased risk from cold stress. After the first two to three days of life, monitoring the central-peripheral temperature difference gives an early indication of cold stress.

Abdomen↗

The BSE crisis.

Explore the source record for details and available documents.

Animals↗

Comparison of nurse and computer charting of physiological variables in an intensive care unit.

OBJECTIVES: To compare charting of physiological parameters manually by nurses and automatically by computer and so decide whether this task could accurately be performed by computer. SUBJECTS/SETTING: 101 consecutive patients admitted for tertiary neonatal intensive care. DESIGN: Direct comparison of 48 hours of data collected by both methods. Computer data stored each second and the hourly median compared with the single hourly value noted by the nurse. METHODS: All patients were monitored by standard patient monitor and a computer. Four physiological parameters were compared between nurse and computer (both derived information from the standard patient monitor): heart rate, transcutaneous oxygen, mean blood pressure, central temperature. A random 51% of patients had the computer data displayed as trends at the cotside. Comparison of the hourly nurse observation and a computer hourly median value. Computer data was compared before and after the removal of artifact. In addition, the effects on nursing observations of either display or non display of the computer trend data was assessed. RESULTS: Nurse and computer observations were statistically significantly different (p < 0.001), though these were not clinically important. Nurses tended to note a higher figure than the computer median. The cotside display of computer data improved consistency between the nurse and computer observations. Artifact present in the data had little influence on the accuracy of the computer median value. CONCLUSIONS: Computer systems can accurately chart physiological data, providing a more flexible record with a minimal risk to data reliability from artifact.

Bias↗

Infection with Ureaplasma urealyticum and Mycoplasma hominis and the development of chronic lung disease in preterm infants.

In a prospective cohort study in a tertiary referral neonatal intensive care unit, the endotracheal secretions of 40 consecutively intubated newborn infants, less than 31 weeks' gestation, were examined weekly for the genital mycoplasmas and all other common bacterial pathogens. Fifteen (37%) infants were positive for Ureaplasma urealyticum and/or Mycoplasma hominis. There were no differences in gestation, birthweight, use of surfactant, or time on ventilator between the culture-positive and negative babies. Thirteen (87%) of the culture-positive group developed chronic lung disease (CLD) compared with 11 (41%) of the negative group (p = 0.0196). Of those culture-positive, 37% were not identified on the first specimen taken at the time of admission. These data suggest a significant association between infection with the urogenital mycoplasma and CLD and also stress the need for repeated cultures to identify these organisms.

Chronic Disease↗

Biochemical markers of bone turnover.

Three studies to evaluate procollagen type I C-terminal propeptide, type I collagen cross-linked telopeptide and bone alkaline phosphatase (BALP) in the assessment of bone turnover and growth in children are presented. (1) In 50 short normal children treated with placebo or growth hormone, delta BALP after 3 months of treatment was highly correlated with height velocity response after 1 year (r = 0.67, p < 0.0001). (2) In 12 children with acute lymphoblastic leukaemia, marked changes in collagen peptides, BALP, and lower leg length velocity were seen during the first 6 months of chemotherapy. Suppression occurred during induction and the two intensification phases, with catch-up during the intervening phase (paired t-tests, p < 0.001). (3) Fourteen babies (birthweight < 1,500 g) treated with high-dose dexamethasone for bronchopulmonary dysplasia were compared with 25 non-steroid-treated babies < 1,500 g. Both collagen peptides decreased rapidly and dramatically (mean decreases 41-68%) after dexamethasone was started, accompanied by weight loss and lower leg shrinkage and followed by recovery during steroid weaning.

Alkaline Phosphatase↗

Mucosal tumor necrosis factor-alpha production and extensive disruption of sulfated glycosaminoglycans begin within hours of birth in neonatal respiratory distress syndrome.

Many of the clinicopathologic features of neonatal respiratory distress syndrome (RDS) may be related to the inflammatory response mounted by the affected infant, although little is known about the interstitial component of this response. We have thus studied the local inflammatory response in this condition by immunohistochemical analysis of whole lung lobes, obtained at postmortem from 40 infants who died from acute RDS in the first week of life. All had demonstrated classical clinical history and histologic features. An archival subgroup from the early 1970s had never received ventilatory support. Immunohistochemical analysis demonstrated rapid temporal increase from birth in the mucosal density of CD68+ macrophages, MAC-387+ monocytes/macrophages, polymorphonuclear neutrophils, and tumor necrosis factor-alpha-immunoreactive cells, maximal in those dying at or after 72 h. Using a cationic probe specific for sulfated glycosaminoglycans (GAGs), the inflammatory infiltration was seen to be associated with striking loss of endothelial, basement membrane, and interstitial GAGs, which was almost complete by 48-72 h. GAG degradation products were found within hyaline membranes in all infants dying after 48 h. This study confirms that neonatal RDS is characterized by intense interstitial inflammation, significantly underestimated on routine staining. This begins within hours of birth and is maximal by 72 h of age. Breakdown of sulfated GAGs within the extracellular matrix follows the same time course and may explain much of the physiologic derangement characteristic of this condition.

Age of Onset↗