Because mean airway pressure (MAP) is extensively used to quantify ventilation administered during the neonatal period, the accuracy and reproducibility of the techniques currently used to define MAP were assessed. All techniques were found to compare closely with MAP measured by integration of the pressure wave form even at ventilator rates in excess of 100 breaths per minute. It was therefore concluded that all methods currently used are satisfactory for clinical use.

Humans↗

PubMedDate not supplied

Ventilatory response to increased dead spaces in the first week of life.

We have developed a method for quantitatively assessing respiratory control in a group of 10 full-term healthy babies, mean age at test 5 days, by measuring their ventilatory response to added external dead spaces. The dead spaces were equal to 0.5, 1, 2, and 3 anatomic dead spaces (2.2 ml/kg body weight), respectively. Tidal volumes were measured by a nasal mask and a 200-I rigid container. End-tidal CO2 was monitored via a tube in the nostril by a mass spectrometer. Baseline measurements were made during a 10-minute period, after which similar recordings were obtained with each of the dead space tubes. The system was calibrated against a 20-ml syringe. The mean baseline ventilation was 602 ml/minute. On the addition of 0.5, 1, 2, and 3 dead spaces, minute ventilations were increased by 37.5, 74.7, 150.7, and 273.6%, respectively. These increases were due to rises in tidal volume rather than respiratory rate. End-tidal CO2 rose by 1.8 and 4 mmHg on the addition of 2 and 3 dead spaces. When the results were compared with expected minute ventilations--based on the baseline recordings and corrected for the added dead spaces and for changes in anatomic dead space ventilation due to alterations in respiratory rate--the results were within 10% of expected values.

Carbon Dioxide↗

PubMedDate not supplied

Determinants of the first inspiratory volume and functional residual capacity at birth.

We have investigated the pattern of pressure and volume changes that occur in vaginally delivered, full-term infants during the onset of spontaneous respiration. Within a few seconds of delivery of the head, simultaneous measurements were made of stomach and esophageal pressure changes together with volume changes determined at the mouth. Values obtained for volume were very similar, but pressure changes were of a greater magnitude than previously reported. A significant correlation has been shown between first inspiratory volume and functional residual capacity (FRC) at the end of the first breath (p less than 0.004). No significant relationship was found between first inspiratory pressure and FRC. However, using a calculated index of inspiratory pressure and time ("inspiratory effort"), a significant relationship of this to FRC was observed (p less than 0.02).

Delivery, Obstetric↗

PubMedDate not supplied

Changing patterns in neonatal respiratory diseases.

Using the current Nottingham Health District, England, as a geographically defined population we have investigated the changing patterns of neonatal respiratory diseases. We have categorized all newborns who developed a respiratory problem during either 1977 or between April 1, 1983, and March 31, 1984 using a system based on that of Hjalmarson (Acta Paediatr Scand 1981; 70:773-783). There has been no change in the incidence of any of the disease types. However, the gestation of babies in two groups, idiopathic respiratory distress syndrome (IRDS) and minimal respiratory disturbance (requiring added oxygen for less than 6 hours), has shown a significant reduction. Overall, mortality for infants developing IRDS has shown a slight decrease, and for infants between 29 and 32 weeks gestation, mortality has shown a significant reduction. Overall, requirements for oxygen therapy and ventilation have shown a threefold increase, while hours in receipt of continuous positive airways pressure (CPAP) have increased sevenfold.

England↗

PubMedDate not supplied

Disentangling perceptual and response bias in unilateral neglect: a methodological proposal.

Bisiach and his colleagues have developed a new version of Milner's "landmark task" for the purpose of separating "perceptual" and "response" biases in neglect patients. Subjects are required to decide which is the longer (or the shorter) of the two portions of a pre-bisected horizontal line. The authors proposed two indices to measure perceptual and response bias respectively. However, these indices are not mathematically independent of one another. Moreover, they do not exploit all of the information available in the data, since they do not consider the effect of the different transection locations across trials. We now propose an alternative means of analyzing data from the revised Landmark task, which generates independent estimates of perceptual and response biases. The method and its theoretical foundation are summarized, and illustrative data obtained from brain damaged patients and control subjects are presented.

Brain↗

PubMedDate not supplied

Paradoxical deterioration in lung function after nebulised salbutamol in wheezy infants.

In 13 infants with a history of wheezing, airways resistance and specific conductance worsened after administration of nebulised salbutamol (0.5 ml sabutamol respirator solution in 1.5 ml normal saline). This paradoxical bronchoconstriction was greatest at 5 min and lasted for up to 15 min. The nebulised solution was found to be acidic and hypo-osmolar, both of which properties have been linked to bronchoconstriction in asthmatic subjects, but even with an initially iso-osmolar solution osmolality increased with time of nebulisation because of evaporation.

Aerosols↗

PubMedDate not supplied

Prehension and perception of size in left visual neglect.

Right hemisphere damaged patients with and without left visual neglect, and age-matched controls had objects of various sizes presented within left or right body hemispace. Subjects were asked to estimate the objects' sizes or to reach out and grasp them, in order to assess visual size processing in perceptual-experiential and action-based contexts respectively. No impairments of size processing were detected in the prehension performance of the neglect patients but a generalised slowing of movement was observed, associated with an extended deceleration phase. Additionally both patient groups reached maximum grip aperture relatively later in the movement than did controls. For the estimation task it was predicted that the left visual neglect group would systematically underestimate the sizes of objects presented within left hemispace but no such abnormalities were observed. Possible reasons for this unexpected null finding are discussed.

Aged↗

PubMedDate not supplied

On the effects of nebulized fenoterol, associated with ipratropium or steroids, on the heart rate of infants under one year of age with acute wheezing.

Explore the source record for details and available documents.

Administration, Intranasal↗

PubMedDate not supplied

Surfactant and respiratory distress syndrome.

Since the late 1950s it has been known that the cause of respiratory distress syndrome (RDS) is surfactant deficiency, especially in preterm infants. But surfactant protein B deficiency may cause RDS in term infants as well. Administration of natural surfactant produce is well known to a rapid improvement in oxygenation within 15 to 20 minutes. The effect of synthetic surfactant is less dramatic. Although randomized controlled trials have been done, the majority have been relatively small. Studies on the role of natural surfactant given to infants with established RDS (rescue therapy) have shown a reduction in the incidence of neonatal death and pneumothorax of 40% and 65%, respectively, compared to untreated infants. However, natural surfactant provides no apparent benefits in terms of the incidence of intraventricular hemorrhage (IVH), patent ductus arteriosus (PDA) or bronchopulmonary dysplasia (BPD). The results of synthetic surfactant given as rescue therapy have shown a similar effect with a 40% reduction in mortality and a 48% reduction in pneumothorax. However, synthetic surfactant also led to a 23% reduction in IVH, 27% in PDA, and 32% in BPD. When natural surfactant is given as prophylaxis (i.e. at or soon after birth, before the development of RDS), the reduction in mortality is 45% and the reduction in pneumothorax is 69%, but as with rescue therapy, there is no effect on the incidence of IVH or BPD. The effect on the incidence of PDA is an increase of 27%. When synthetic surfactants are given prophylactically, there is a similar reduction in mortality of 44% and a reduction in pneumothorax of 36%. The incidence of IVH and BPD is unchanged, but as with the natural surfactant, there is a small increase in the incidence of PDA of 27%. The main side effect is pulmonary hemorrhage that has been reported to occur in 4-7% of infants given surfactant. Although the administration of surfactant has had a dramatic effect on neonatal practice, it is likely that further studies will lead to more appropriate use of surfactant.

Drug Combinations↗