Search PubMed⌕ Search

Biomedical subjects

H Vyas

Publications and source records attributed to H Vyas.

35 records · Page 2Linked to original sources
PubMed1987

Endotracheal resuscitation of preterm infants at birth.

The adequacy of initial ventilation in 21 preterm babies (25-36 weeks' gestation), who required endotracheal intubation and positive pressure ventilation, were studied. Pressure and flow were measured at the proximal end of the endotracheal intubation tube and expiratory volume calculated from the flow trace. The results were compared with those from a group of 26 term infants who also required resuscitation. Five of 21 preterm babies (24%) had adequate tidal ventilation with the first inflation. This rose to seven of 21 (33%) by the third inflation. This was significantly less than the results in the term infants (chi 2 = 4.38 p less than 0.05). Respiratory reflex responses to resuscitation were seen in 41% of inflations in preterm and 56% of inflations in term infants. There was a significant correlation between reflex activity and adequate ventilation in the preterm group (chi 2 = 11.83, p less than 0.001) but not in the term group (chi 2 = 0.212, p = NS). No correlation was seen between initial ventilation and outcome.

Humans↗
PubMed1986

The child health clinic: results of a new strategy of community care in a deprived area.

Substantial changes were made in the organisation of a child health clinic serving an underprivileged population in Nottingham. A community paediatric team approach was adopted, routine medical checks were reduced, and referrals from elsewhere (including parents) were encouraged. The changes resulted in an older and more deprived population of preschool children being seen by the clinic doctors. More treatable medical disorders were detected with this approach.

Age Factors↗
PubMed1985

Continuous positive airway pressure via a single nasal catheter in preterm infants.

We present the results of giving continuous positive airway pressure (CPAP) via a single nasal catheter to 20 preterm infants. A beneficial effect in terms of reduced work of breathing (P less than or equal to 0.01) and improved pattern of respiration (P less than or equal to 0.05) are demonstrated. CPAP via a single nasal catheter does not seem to mediate effects inside the thorax unlike CPAP delivered by a tight fitting face mask. Gross variations in CPAP level may result from altering the infant's position.

Apnea↗
PubMed1984

Efficacy of facemask resuscitation at birth.

The efficacy of facemask resuscitation was assessed by measuring the expiratory tidal volume during the first three inflations in nine babies with birth asphyxia and comparing the results with those obtained in a further nine babies resuscitated after endotracheal intubation. The facemask system was relatively inefficient, with tidal exchange less than one third of that seen after intubation and rarely sufficient to produce adequate alveolar ventilation. Successful resuscitation depended on stimulating the baby to make his own respiratory efforts.

Asphyxia Neonatorum↗
PubMed1984

Effect of exogenous surfactant on total respiratory system compliance.

We measured total respiratory system compliance (Crs) before and after instilling 25 mg artificial surfactant in 1 ml saline down the endotracheal tube of preterm babies requiring resuscitation at birth, and compared results with data from 6 similar babies receiving saline only. Surfactant did not produce a significant improvement in Crs.

Clinical Trials as Topic↗
PubMed1983

Face mask resuscitation: does it lead to gastric distension?

Inflation and oesophageal pressures were recorded simultaneously during bag and mask resuscitation of 9 asphyxiated babies. After half a minute of standard inflation pressures, higher pressures were applied for at least 5 inflations by occluding the blow-off valve. No air entered the oesophagus until a high mean inflation pressure of 5.4 kPa was exceeded. These findings were confirmed in 4 fresh stillborn babies studied similarly. We conclude that resuscitation using bag and mask, applying pressures less than 3.5 kPa, should not lead to gastric distension.

Asphyxia Neonatorum↗
PubMed1983

Effects of artificial surfactant on lung function and blood gases in idiopathic respiratory distress syndrome.

We have investigated the effect of giving two 25 mg doses of dry surfactant powder to the airways of 10 preterm babies with severe idiopathic respiratory distress syndrome requiring intermittent positive pressure ventilation. No useful change in static total compliance or blood gases was seen. We conclude that dry surfactant powder does not have a role in the management of severe idiopathic respiratory distress syndrome.

Carbon Dioxide↗
PubMed1983

Role of labour in the establishment of functional residual capacity at birth.

Intrathoracic pressure and volume changes were measured during the spontaneous first breath in 11 healthy term neonates delivered by emergency caesarean section (CS). Although inspiratory and expiratory rates were higher than those found among babies delivered by elective CS, inspiratory volume was very similar and these babies, unlike those delivered by elective CS, had all formed a functional residual capacity at the end of the first breath. We obtained cord arterial and venous samples for catecholamine analysis concurrently, and found that most of the babies had concentrations of plasma noradrenaline similar to babies delivered by elective CS--high values were found only among infants who had suffered fetal distress. Both catecholamine excretion and method of delivery may be important in the formation of the functional residual capacity at birth.

Cesarean Section↗
PubMed1981

Physiologic responses to prolonged and slow-rise inflation in the resuscitation of the asphyxiated newborn infant.

Measurements of thoracic volume, inflation pressure, and intrathoracic pressure have been recorded at the resuscitation of nine newborn babies. The initial inflation pressure was maintained for approximately five seconds which produced a twofold increase in inflation volume compared to standard resuscitation techniques and always led to formation of an FRC. When the inflation pressure was increased slowly over three to five seconds, the apparent opening pressure which occurred universally in square wave inflation was rarely seen.

Asphyxia Neonatorum↗
PubMed1981

Intrathoracic pressure and volume changes during the spontaneous onset of respiration in babies born by cesarean section and by vaginal delivery.

We studied the first breath of newborn infants delivered by cesarean section. Inspiratory pressure and volume were found to be similar to those in infants born vaginally. However, the expiratory and delivery pressures were found to be smaller. Functional residual capacity was formed less frequently after cesarean section than in the vaginally delivered group.

Cesarean Section↗
PubMed1981

Relationship between apnoea and bradycardia in preterm infants.

Nine studies were carried out on seven babies who were having repeated episodes of bradycardia without any clinically obvious apnoea. Their mean gestational age was 31.7 weeks (range 29 to 36 weeks) and the mean birth weight was 1.56 kg (range 1.08 kg to 2.16 kg). Investigations were carried out in a total body plethysmograph. Face mask with a pneumotachograph attached to it measured flow. Tidal volume was obtained by integrating these signals. An oesophageal balloon measured intrathoracic pressure changes and the heart rate was measured from ECG chest electrodes. A total of 172 episodes of apnoea were observed. In 50% of these apnoeas, the airway was closed as determined by the absence of cardiac artefact on the flow signals. Apnoea was associated with bradycardia in just over 25% of all apnoea. It tended to occur early (11 to 14 sec). Whether the apnoea was central or obstructive had no effect on the pattern provided the baby did not make any inspiratory efforts. Inspiration against a closed airway produced bradycardia in over 50% of obstructive apnoea, the heart rate falling precipitously within 1 to 2 sec. These findings indicate that often bradycardias occur too early in apnoea to be due to central hypoxia and must be due to a peripheral mechanism.

Apnea↗
PubMed1980

Hormonal abnormalities of the pancreas and gut in cystic fibrosis.

We have investigated the effect of cystic fibrosis on alimentary hormones in 10 children by measuring the pancreatic and gut hormone rsponse to a milk drink. Plasma insulin and gastric inhibitory peptide were both significantly reduced (P < 0.05 and P < 0.005, respectively, at 15 min) in the patients with cystic fibrosis, compared with controls, even though the early glucose rise was greater in the former group (P < 0.05 at 15 min). Fasting levels of pancreatic polypeptide were significantly lower in the fibrocystic children (P < 0.01), and the normal response to milk was completely abolished in these patients (P < 0.001). Fasting plasma enteroglucagon concentrations were grossly abolished in the cystic fibrosis patients (P < 0.001) and these remained elevated throughout the test. No significant differences were seen in basal or postmilk responses of plasma glucagon, gastrin, secretin, vasoactive intestinal peptide, or motilin in cystic fibrosis. It would thus appear that the pancreatic polypeptide cell is more susceptible to the effects of the disease process than the beta or alpha cell in cystic fibrosis. Some aspects of the abnormalities in the gastrointestinal endocrine system were similar to those seen in celiac disease and tropical sprue and may, therefore, effect a similar hormonal response in these patients with cystic fibrosis to those with mucosal damage.

Adolescent↗
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

Selection of pulse oximetry equipment for ambulatory monitoring.

PRIMARY OBJECTIVE: This communication describes the initial stage of a research project concerning the monitoring of SpO2 in infants prone to periods of spontaneous oxygen desaturation whilst freely moving around their home environment. The primary aim was to determine an appropriate probe type and site together with an assessment of the suitability of two commercially available oximeter units. RESEARCH DESIGN: The study comprised 19 comparative tests, totalling 162 hours of recordings at resolution one sample every four seconds. Comparisons are drawn between probes, probe sites and pulse oximeters. MAIN OUTCOMES/RESULTS: The bias and precision is presented with respect to the probe and measurement site. Also, correlation between the trial and reference recordings is considered. CONCLUSIONS: It is concluded that ambulatory recording of SpO2 in infants utilizing equipment suitable for home monitoring can produce diagnostic data equivalent to that of the Ohmeda 3700 biox, but that an indication of movement artefact may be required for confirmation of accuracy. It became apparent that 'wrap around' probes, used on the index finger or big toe are the most suitable.

Child↗