Water-sealed spirometer for measurements in newborns and infants.

Details are given of two spirometers for use in neonates and infants < 12 mo old. The minimum volumes are 520 and 670 ml, respectively. The maximum volume changes that can be recorded are 250 and 450 ml, respectively. The minimal detectable volume changes are 0.4 and 0.6 ml, respectively. Rebreathing of dead space gas is prevented by a fan producing a flow of 6.2 and 10.2 l/min, respectively; 100% gas mixing after injecting a gas bolus in the two spirometers is achieved in 5.7 and 6.6 s, respectively. Resistance to airflow is 0.2 kPa.l-1.s (2 cmH2O.l-1.s) at 150 ml/s in both spirometers. The frequency response of both instruments is flat to 6 cycles/s. The instruments can be easily cleaned and are suitable for bedside measurements.

Influence of the oestrous cycle on experimental intrauterine E. coli infection in the sow.

The influence of the oestrous cycle on the onset of endometritis in the sow was studied. Ten pubertal, unmated gilts of the Belgian Negative Landrace were used. Nine gilts were inoculated into the uterus by laparotomy with a suspension of an E. coli strain isolated from the uterus of a discharging sow from a herd having many problems with vaginal discharge and a lowered fertility. One gilt was as a control inoculated with 2 ml of a PBS-solution. All sows inoculated during dioestrus developed clinical symptoms, but only 1 of the 5 gilts inoculated at standing oestrus developed a vaginal discharge. These data confirm the hypothesis that the stage of the oestrous cycle has an important influence on the onset of endometritis. The resistance to E. coli infections was higher when the gilts were inoculated during oestrus.

Cerebral and aortic blood flow velocity patterns in preterm infants receiving prophylactic surfactant treatment.

Blood velocity in the internal carotid artery (ICA) and in the descending thoracic aorta (DAo) was investigated used Duplex-Doppler ultrasound in 14 infants of less than 30 weeks gestation, treated prophylactically with surfactant, and in 11 comparable infants with relatively mature lungs who served as controls. After surfactant administration, blood gases, pH or FiO2 were not different between the groups. Temporal mean blood velocity in the ICA was used as a relative measure of cerebral flow (TMFV-cer), and its coefficient of variation (CV-cer) was used to assess fluctuations in cerebral blood velocity. The pulsatility index (PI) in the ICA (PI-cer) and DAo (PI-DAo) was used to estimate if a left-to-right shunt was present. During surfactant instillation TMFV-cer was abnormally low and CV-cer indicated a fluctuating cerebral blood velocity. At 10 min after surfactant administration, TMFV-cer of the treated infants was higher compared to the controls, while CV-cer was stable in both groups. PI-cer and PI-DAo were abnormally high during the first hour of life after surfactant treatment, suggesting a left-to-right shunt without, however, clinical signs of a hemodynamically important ductus arteriosus. We suggest that cerebral perfusion is affected during and at 10 min after surfactant instillation. Left-to-right shunting appears to be a common event following surfactant treatment.