Passive compliance (C) has been measured in 10 infants at 10--90 min after birth and in 10 infants at a few days of life by recording mouth pressure after airways occlusions at end inspiration. From the slope of the expiratory flow-volume curve, the passive time constant (tau) and resistance (R = tau/C) have been also computed. Examination of the changes of C with time and of the expiratory flow-volume curves indicates that the end-expiratory volume is maintained above functional residual capacity at both ages, but significantly more so at a few days (7.6 ml) than at 10--90 min (3.5 ml). The passive time constant (tau = C . R) is shorter at the early age due to the smaller C. The active compliance (C') and resistance (R') values have been estimated from the pressure generated by the infant when the airways are occluded at end expiration. The active time constant of the respiratory system (tau' = C' . R') is less than tau, due to a smaller active compliance, particularly at a few days. The active resistance is on the contrary similar to R. The active stiffening of the respiratory system provides more stability of the infant's respiratory system and a more ready volume response for any given change in pressure; its price, however, is a higher work of breathing. At optimal breathing rates, in fact, the active work is 127% (10--90 min) to 183% (a few days) higher than that computed from the passive values. The inspiratory flow wave tends to be squared at both ages minimizing the energy losses due to friction.
outside hospital; part of the reason was that black people were less likely to have cardiopulmonary resuscitation started by a bystander than were white people.4 It may be worth examining the way the public responds to cardiac arrest in different groups. CONCLUSIONThe most impressive predictor of survival was if the cardiopulmonary resuscitation Design-Prospective cohort study with follow up at one day, seven days, and six weeks after delivery.Setting-Teaching hospital in Montreal. Subjects-329 women who delivered a live infant(s) during the study period. Exclusion criteria were back pain before pregnancy and delivery by elective caesarean section.
Difficult or failed tracheal intubation is an important
Purpose: To determine the effect of epidural analgesia on biochemical markers of stress, plasma oxytocin concentrations and frequency of uterine contractions during the first stage of labour. Methods: Nine nulliparous women, in spontaneous labour, with a singleton fetus and cervical dilatation < 5 cm were enrolled. Epidural bupivacaine 0.25% (range I 0 -14 ml) was administered and bilateral sensory blockade to ice 0-8 -L4) achieved. Blood samples were collected before the epidermal block and every I0 min for one hour after the block was achieved for the measurement of plasma beta-endorphin, cortical, glucose, lactate and oxytocin concentrations. No exogenous oxytocin was given. Intensity of pain was assessed at the time of the blood sampling using a I0 cm visual analogue scale (VAS). The frequency of uterine contractions was recorded for 60 rain before and after the epidural block.Results: There was a decrease in plasma beta-endorphin and cortisol concentrations after epidural block (P < 0.01).There were no changes in plasma glucose and lactate concentrations. The mean VAS for pain decreased I0 rain after epidural block was achieved and remained < 2 throughout the study period (P < 0.001 ). Mean plasma oxytocin concentrations did not change. The frequency of uterine contractions before and after the epidural block was similar. Condusions: The metabolic stress response to the pain of labour was attenuated by epidural analgesia. In contrast, plasma oxytocin concentration and frequency of uterine contractions were unaffected by the attenuation of metabolic stress response.Object~ : D&erminer reffet de l'analg&ie p&idurale sur les marqueurs biochimiques de stress, les concentrations plasmatiques d'oxytocine et la frdquence des contractions ut&ines pendant le premier stade du travail. M&hode : Neuf femmes nullipares, en travail spontan6, porteuse d'un seul foetus et pr&entant une dilatation du col de l'ut&us < 5 cm, ont dtd recrut&s. On a administrd de la bupivaca'ine p&idurale ~ 0,25 % (de I0 ~ 14 ml) et on a procddd ~ un blocage sensoriel bilat&al ~ la glace (-I-8 -I_4). On a prdlevd des &hantillons de sang avant le point dermique et ~ toutes les I0 minutes pendant une heure apt& le bloc afin de mesurer les concentrations plasmatiques de 13-endorphine, de cortisol, de glucose, de lactate et d'oxytocine. On n'a pas administrd d'oxytocine exog~ne. l'intensitd de la douleur a 6td dvalu6e au moment des prdl~vements sanguins en utilisant une &helle visuelle analogique (EVA) de 10 cm. La frdquence des contractions ut&ines a &d enregistr6e pendant 60 minutes avant et apr& I'analg6sie p&idurale. R&ultats : On a observd une baisse de la 13-endorphine plasmatique et des concentrations de cortisol apr& ranalg&ie p&idurale (P < 0,01). II n'y a pas eu de changements dans les concentrations de glucose et de lactate. La moyenne de rEVA pour la dou~eur a diminu~, I0 minutes apr~s le bloc p6ridural et est demeur& < 2 pendant toute la dur& de l'&ude (m < 0,00 I). Les concentrations moyennes d'oxytocine front pas changd. La frdquence...
We studied the ventilatory parameters and the pattern of breathing including the onset of respiration in 20 healthy infants immediately after cesarean-section delivery. In eight of the infants further measurements were obtained at 60 min of life. The pattern of breathing immediately after delivery is very irregular with a marked tendency to keep the lung inflated mainly through interruptions of expiration. After the first expiration some air remains in the lung representing the formation of functional residual capacity (FRC). FRC obtained with the first breath is proportional to the previous inspired volume and is the largest contribution towards the full establishment of FRC. Tidal volume and FRC of the first breath are similar to that reported in babies delivered vaginally, which suggests that the forces required for lung inflation are similar in the two groups of infants. The first breath tends to be deeper and slower and has a longer expiratory time than subsequent breaths. At 60 min of life the respiratory pattern becomes more regular, tidal volume is further decreased, and respiratory frequency is increased through a reduction of expiratory time.
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