Interactions among peripheral perfusion, cardiac activity, oxygen saturation, thermal profile and body position in growing low birth weight infants

AIMS

To investigate the correlation between the 'perfusion index' (PI) and other commonly used estimates of cutaneous blood flow [heart rate (HR), surface temperatures (ST) and central-to-peripheral thermal gradients (C-P grad)] and to use this new non-invasive tool to compare differences between prone and supine sleep position in low birth weight (LBW) infants.

METHODS

Six-hour continuous recordings of pulse oximetry, cardiac activity and absolute ST from three sites (flank, forearm and leg), along with minute-to-minute assessment of behavioural states were performed in 31 LBW infants. Infants were randomly assigned to the prone or supine position for the first 3 h and then reversed for the second 3 h. PI data were correlated with HR and C-P grad, and compared across sleep positions during quiet sleep (QS) and active sleep (AS).

RESULTS

Perfusion index correlated significantly with HR (r(2) = 0.40) and flank-to-forearm thermal gradient (r(2) = 0.28). In the prone position during QS, infants exhibited higher PI (3.7 +/- 0.9 vs. 3.1 +/- 0.7), HR (158.4 +/- 8.9 vs. 154.1 +/- 8.8 bpm), SpO(2) (95.8 +/- 2.6 vs. 95.2 +/- 2.6%), flank (36.7 +/- 0.4 vs. 36.5 +/- 0.4 degrees C), forearm (36.1 +/- 0.6 vs. 35.5 +/- 0.4 degrees C) and leg (35.4 +/- 0.7 vs. 34.7 +/- 0.7 degrees C) temperatures and narrower flank-to-forearm (0.6 +/- 0.4 vs. 0.9 +/- 0.3 degrees C) and flank-to-leg (1.3 +/- 0.6 vs. 1.8 +/- 0.7 degrees C) gradients, compared to those of the supine position. Similar differences were observed during AS.

CONCLUSION

Perfusion index is a good non-invasive estimate of tissue perfusion. Prone sleeping position is associated with a higher PI, possibly reflecting thermoregulatory adjustments in cardiovascular control. The effects of these position-related changes may have important implications for the increased risk for sudden infant death syndrome in prone position.

Hydatid disease of the lung mimicking a pericardial cyst

We report a young girl who presented to us with chest discomfort and had a paracardiac mass on chest radiograph. Computerised tomographic (CT) scan of the thorax was suggestive of pericardial cyst. Hydatid serology was negative. The cyst was excised.

Sudden collapse of a young female cross country runner

The case is reported of a young previously healthy female cross country runner who collapsed on completion of a cross country run. The cause of the collapse was non-cardiogenic pulmonary oedema as a manifestation of hyponatraemic encephalopathy. The concurrent occurrence of non-cardiogenic pulmonary oedema and encephalopathy due to hyponatraemia is unusual.

Prevalence of tobacco use among school going youth in North Indian States

BACKGROUND

Tobacco use, which is the cause of several respiratory diseases, generally starts in the teens. Global Youth Tobacco Survey (GYTS) is an international initiative to investigate the tobacco use in school going youth of 13 to 15 years of age. This report describes the GYTS findings in the North Indian region.

METHODS

A two-stage cluster sample was used with selection of schools on probability proportional to enrollment size followed by systematic equal probability sampling with a random start of classes from each school. The 85-item questionnaire included 'core GYTS' and other additional questions. Data analysis was performed using EpiInfo 3.2 software and the results accounted for the complex sampling design and weighting factors in the data set.

RESULTS

The sample consisted of 9319 students out of the total eligible population of 30488 from 100 schools. The prevalence of ever-use of tobacco varied between 2.9 to 8.5% in boys and 1.5 to 9.8% in girls. The prevalence was highest in Chandigarh and lowest in Punjab. Between 16 to 46% of students were exposed to the habit of tobacco among parents or friends. There were 10 to 34% students who were passively exposed to environmental tobacco smoke.

CONCLUSION

Tobacco use is present in up to 10 percent of school going youth in the region. A majority of them had desired to quit. Tobacco control and cessation programmes therefore, remain important health issues.

Sleeping position and electrocortical activity in low birthweight infants

OBJECTIVE

To evaluate the effects of prone and supine sleeping positions on electrocortical activity during active (AS) and quiet (QS) sleep in low birthweight infants.

DESIGN

Randomised/crossover study.

SETTING

Infant Physiology Laboratory at Children's Hospital of New York.

PATIENTS

Sixty three healthy, growing, low birthweight (birth weight 795-1600 g) infants, 26-37 weeks gestational age.

INTERVENTIONS

Six hour continuous two channel electrocortical recordings, together with minute by minute behavioural state assignment, were performed. The infants were randomly assigned to prone or supine position during the first three hours, and positions were reversed during the second three hours.

OUTCOME MEASURES AND RESULTS

Fast Fourier transforms of electroencephalograms (EEGs) were performed each minute and the total EEG power (TP), spectral edge frequency (SEF), absolute (AP) and relative (RP) powers in five frequency bands (0.01-1.0 Hz, 1-4 Hz, 4-8 Hz, 8-12 Hz, 12-24 Hz) were computed. Mean values for TP, SEF, AP, and RP in the five frequency bands in the prone and supine positions during AS and QS were then compared. In the prone sleeping position, during AS, infants showed significantly lower TP, decreased AP in frequency bands 0.01-1.0 Hz, 4-8 Hz, 8-12 Hz, 12-24 Hz, increased RP in 1-4 Hz, and a decrease in SEF. Similar trends were observed during QS, although they did not reach statistical significance.

CONCLUSIONS

The prone sleeping position promotes a shift in EEG activity towards slower frequencies. These changes in electrocortical activity may be related to mechanisms associated with decreased arousal in the prone position and, in turn, increased risk of sudden infant death syndrome.

Adiponectin receptors gene expression and insulin sensitivity in non-diabetic Mexican Americans with or without a family history of Type 2 diabetes

AIMS/HYPOTHESIS

The recent discovery of two adiponectin receptors (AdipoR1 and AdipoR2) will improve our understanding of the molecular mechanisms underlying the insulin-sensitising effect of adiponectin. The aim of this study was to determine for the first time whether skeletal muscle AdipoR1 and/or AdipoR2 gene expression levels are associated with insulin resistance.

METHODS

Using RT-PCR and northern analysis we measured AdipoR1 and AdipoR2 gene expression in skeletal muscle from healthy Mexican Americans with normal glucose tolerance who had (n=8) or did not have (n=10) a family history of Type 2 diabetes.

RESULTS

Gene expression profiling indicated that the AdipoR1 and AdipoR2 isoforms are highly expressed in human skeletal muscle, unlike in mice where AdipoR2 expression was highest in the liver, and AdipoR1 was highest in skeletal muscle. In the study subjects, the expression levels of AdipoR1 (p=0.004) and AdipoR2 (p=0.04), as well as plasma adiponectin concentration (p=0.03) were lower in people with a family history of Type 2 diabetes than in those with no family history of the disease. Importantly, the expression levels of both receptors correlated positively with insulin sensitivity (r=0.64, p=0.004 and r=0.47, p=0.048 respectively).

CONCLUSIONS/INTERPRETATION

Collectively, these data indicate that both isoforms of the adiponectin receptor play a role in the insulin-sensitising effect of adiponectin.

Unconventional diagnosis of Normandy-type von Willebrand's disease in a blood donor

We report the case of a long-standing female blood donor whose blood donation was processed for cryoprecipitate. The cryoprecipitate unit was chosen at random for FVIII:C estimation as part of the quality control, and a low FVIII:C level was identified. The cause of this was subsequently shown to be the Normandy variant of type-2 von Willebrand's disease due to a homozygous Arg854Gln mutation in the von Willebrand factor gene.