Endotracheal Continuous Positive Airway Pressure Research Articles

Accuracy of Spontaneous Breathing Trial Using ET-CPAP in Predicting Successful Extubation of Neonates.

Objective: Extubation failure is common in mechanically ventilated neonates. Finding objective criteria for predicting successful extubation may help to reduce the incidence of failure and the length of mechanical ventilation (MV). We conducted this study to determine the accuracy of the spontaneous breathing trial (SBT) and lung function measurements in predicting successful extubation in neonates. Methodology: This cross-sectional validation study was conducted at a tertiary care neonatal intensive care unit (NICU) over 12 months from December 2019 to December 2020. Neonates intubated for >24 hours and considered ready for extubation were enrolled in the study. Neonates who met defined eligibility criteria underwent a three minutes SBT using endotracheal continuous positive airway pressure (ET-CPAP) before extubation. The primary clinical team was blinded to the results, and all neonates were extubated after SBT. Extubation was considered successful if patients remained extubated for 48 hours.Results: Among the 107 infants, 77.5% (n=83) of infants passed the SBT. Of these, 78 were successfully extubated, giving the positive predictive value of 93.97%. The overall extubation success rate was 90% (n=96). The sensitivity and specificity of SBT were 81.2% and 54.5%, respectively. VE (ET-CPAP) and VE-ventilator at a cutoff of ≥238 ml and ≥143.7 ml have an area under the curve (AUC) of 0.77 and 0.75 respectively to predict successful extubation (p-value 0.003, 0.008 respectively). Conclusion: SBT predicts extubation success with pronounced accuracy. Therefore, we propose SBT as a valuable and crucial step that guides clinicians' decision-making regarding extubation preparedness or impending failure in neonates.

Does a brief trial of endotracheal CPAP before extubation increase the work of breathing in preterm infants?

A brief period of endotracheal continuous positive airway pressure (ETT-CPAP) can predict extubation outcome but longer periods are associated with increased work of breathing and extubation failure. In ventilated preterm infants, brief ETT-CPAP does not increase the work of breathing and can be used to predict the outcome of extubation.

Continuous positive airway pressure (CPAP) for respiratory distress in preterm infants.

Respiratory distress, particularly respiratory distress syndrome (RDS), is the single most important cause of morbidity and mortality in preterm infants. In infants with progressive respiratory insufficiency, intermittent positive pressure ventilation (IPPV) with surfactant has been the usual treatment, but it is invasive, potentially resulting in airway and lung injury. Continuous positive airway pressure (CPAP) has been used for the prevention and treatment of respiratory distress, as well as for the prevention of apnoea, and in weaning from IPPV. Its use in the treatment of RDS might reduce the need for IPPV and its sequelae. To determine the effect of continuous distending pressure in the form of CPAP on the need for IPPV and associated morbidity in spontaneously breathing preterm infants with respiratory distress. We used the standard strategy of Cochrane Neonatal to search CENTRAL (2020, Issue 6); Ovid MEDLINE and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Daily and Versions; and CINAHL on 30 June 2020. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. All randomised or quasi-randomised trials of preterm infants with respiratory distress were eligible. Interventions were CPAP by mask, nasal prong, nasopharyngeal tube or endotracheal tube, compared with spontaneous breathing with supplemental oxygen as necessary. We used standard methods of Cochrane and its Neonatal Review Group, including independent assessment of risk of bias and extraction of data by two review authors. We used the GRADE approach to assess the certainty of evidence. Subgroup analyses were planned on the basis of birth weight (greater than or less than 1000 g or 1500 g), gestational age (groups divided at about 28 weeks and 32 weeks), timing of application (early versus late in the course of respiratory distress), pressure applied (high versus low) and trial setting (tertiary compared with non-tertiary hospitals; high income compared with low income) MAIN RESULTS: We included five studies involving 322 infants; two studies used face mask CPAP, two studies used nasal CPAP and one study used endotracheal CPAP and continuing negative pressure for a small number of less ill babies. For this update, we included one new trial. CPAP was associated with lower risk of treatment failure (death or use of assisted ventilation) (typical risk ratio (RR) 0.64, 95% confidence interval (CI) 0.50 to 0.82; typical risk difference (RD) -0.19, 95% CI -0.28 to -0.09; number needed to treat for an additional beneficial outcome (NNTB) 6, 95% CI 4 to 11; I2 = 50%; 5 studies, 322 infants; very low-certainty evidence), lower use of ventilatory assistance (typical RR 0.72, 95% CI 0.54 to 0.96; typical RD -0.13, 95% CI -0.25 to -0.02; NNTB 8, 95% CI 4 to 50; I2 = 55%; very low-certainty evidence) and lower overall mortality (typical RR 0.53, 95% CI 0.34 to 0.83; typical RD -0.11, 95% CI -0.18 to -0.04; NNTB 9, 95% CI 2 to 13; I2 = 0%; 5 studies, 322 infants; moderate-certainty evidence). CPAP was associated with increased risk of pneumothorax (typical RR 2.48, 95% CI 1.16 to 5.30; typical RD 0.09, 95% CI 0.02 to 0.16; number needed to treat for an additional harmful outcome (NNTH) 11, 95% CI 7 to 50; I2 = 0%; 4 studies, 274 infants; low-certainty evidence). There was no evidence of a difference in bronchopulmonary dysplasia, defined as oxygen dependency at 28 days (RR 1.04, 95% CI 0.35 to 3.13; I2 = 0%; 2 studies, 209 infants; very low-certainty evidence). The trials did not report use of surfactant, intraventricular haemorrhage, retinopathy of prematurity, necrotising enterocolitis and neurodevelopment outcomes in childhood. In preterm infants with respiratory distress, the application of CPAP is associated with reduced respiratory failure, use of mechanical ventilation and mortality and an increased rate of pneumothorax compared to spontaneous breathing with supplemental oxygen as necessary. Three out of five of these trials were conducted in the 1970s. Therefore, the applicability of these results to current practice is unclear. Further studies in resource-poor settings should be considered and research to determine the most appropriate pressure level needs to be considered.

Diaphragmatic activity and neural breathing variability during a 5-min endotracheal continuous positive airway pressure trial in extremely preterm infants.

BackgroundExtremely preterm infants are often exposed to endotracheal tube continuous positive airway pressure (ETT-CPAP) trials to assess extubation readiness. The effects of ETT-CPAP trial on their diaphragmatic activity (Edi) and breathing variability is unknown.MethodsProspective observational study enrolling infants with birth weight ≤1250 g undergoing their first extubation attempt. Diaphragmatic activity, expressed as the absolute minimum (Edi min) and maximum values (Edi max), area under the Edi signal, and breath-by-breath analyses for breath areas, amplitudes, widths, and neural inspiratory and expiratory times, were analyzed during mechanical ventilation (MV) and ETT-CPAP. Neural breathing variability of each of these parameters was also calculated and compared between MV and ETT-CPAP.ResultsThirteen infants with median (interquartile range) birth weight of 800 g [610–920] and gestational age of 25.4 weeks [24.4–26.3] were included. Diaphragmatic activity significantly increased during ETT-CPAP when compared to MV:Edi max (44.2 vs. 38.1 μV), breath area (449 vs. 312 μV·s), and amplitude (10.12 vs. 7.46 μV). Neural breathing variability during ETT-CPAP was characterized by increased variability for amplitude and area under the breath, and decreased for breath time and width.ConclusionsA 5-min ETT-CPAP in extremely preterm infants undergoing extubation imposed significant respiratory load with changes in respiratory variability.Impact ETT-CPAP trials are often used to assess extubation readiness in extremely preterm infants, but its effects upon their respiratory system are not well known.Diaphragmatic activity analysis demonstrated that these infants are able to mount an important response to a short trial.A 5-min trial imposed a significant respiratory load evidenced by increased diaphragmatic activity and changes in breathing variability.Differences in breathing variability were observed between successful and failed extubations, which should be explored further in extubation readiness investigations.This type of trial cannot be recommended for preterm infants in clinical practice until clear standards and accuracy are established.

Assessment of Extubation Readiness Using Spontaneous Breathing Trials in Extremely Preterm Neonates

Spontaneous breathing trials (SBTs) are used to determine extubation readiness in extremely preterm neonates (gestational age ≤28 weeks), but these trials rely on empirical combinations of clinical events during endotracheal continuous positive airway pressure (ET-CPAP). To describe clinical events during ET-CPAP and to assess accuracy of comprehensive clinical event combinations in predicting successful extubation compared with clinical judgment alone. This multicenter diagnostic study used data from 259 neonates seen at 5 neonatal intensive care units from the prospective Automated Prediction of Extubation Readiness (APEX) study from September 1, 2013, through August 31, 2018. Neonates with birth weight less than 1250 g who required mechanical ventilation were eligible. Neonates deemed to be ready for extubation and who underwent ET-CPAP before extubation were included. In the APEX study, cardiorespiratory signals were recorded during 5-minute ET-CPAP, and signs of clinical instability were monitored. Four clinical events were documented during ET-CPAP: apnea requiring stimulation, presence and cumulative durations of bradycardia and desaturation, and increased supplemental oxygen. Clinical event occurrence was assessed and compared between extubation pass and fail (defined as reintubation within 7 days). An automated algorithm was developed to generate SBT definitions using all clinical event combinations and to compute diagnostic accuracies of an SBT in predicting extubation success. Of 259 neonates (139 [54%] male) with a median gestational age of 26.1 weeks (interquartile range [IQR], 24.9-27.4 weeks) and median birth weight of 830 g (IQR, 690-1019 g), 147 (57%) had at least 1 clinical event during ET-CPAP. Apneas occurred in 10% (26 of 259) of neonates, bradycardias in 19% (48), desaturations in 53% (138), and increased oxygen needs in 41% (107). Neonates with successful extubation (71% [184 of 259]) had significantly fewer clinical events (51% [93 of 184] vs 72% [54 of 75], P = .002), shorter cumulative bradycardia duration (median, 0 seconds [IQR, 0 seconds] vs 0 seconds [IQR, 0-9 seconds], P < .001), shorter cumulative desaturation duration (median, 0 seconds [IQR, 0-59 seconds] vs 25 seconds [IQR, 0-90 seconds], P = .003), and less increase in oxygen (median, 0% [IQR, 0%-6%] vs 5% [0%-18%], P < .001) compared with neonates with failed extubation. In total, 41 602 SBT definitions were generated, demonstrating sensitivities of 51% to 100% (median, 96%) and specificities of 0% to 72% (median, 22%). Youden indices for all SBTs ranged from 0 to 0.32 (median, 0.17), suggesting low accuracy. The SBT with highest Youden index defined SBT pass as having no apnea (with desaturation requiring stimulation) or increase in oxygen requirements by 15% from baseline and predicted extubation success with a sensitivity of 93% and a specificity of 39%. The findings suggest that extremely preterm neonates commonly show signs of clinical instability during ET-CPAP and that the accuracy of multiple clinical event combinations to define SBTs is low. Thus, SBTs may provide little added value in the assessment of extubation readiness.

Effect of maturity and infection on the rate of relaxation of the respiratory muscles in ventilated, newborn infants.

To assess the respiratory muscle time constant of relaxation (τ), an index of respiratory muscle function in ventilated newborns. Sixty-two infants (42 born prematurely) with a median gestational age of 29 [interquartile range (IQR) 26-37] weeks were prospectively studied. Measurement of τ was taken during spontaneous breathing on endotracheal continuous positive airway pressure prior to extubation, and τ was calculated from the reciprocal of the slope of the airway pressure decline versus time. Infants were classified as having had systemic or respiratory infection (positive microbiology) if they had any positive bacterial blood or respiratory culture prior to measurement. Measurement of τ was taken at a median post-natal age of 6 (IQR 3-29) days. The median τ was higher in premature infants [17.4 (IQR 7.7-28.3) sec/cmH2 O] compared to term infants [6.8 (IQR 4.4-8.7) sec/cmH2 O, p<0.001]. The median τ was higher in infants who had had positive microbiology [17.6 (IQR 9.9-29.1) sec/cmH2 O] compared to infants with negative microbiology [8.0 (IQR 6.3-17.9) sec/cmH2 O, p=0.034]. τ was related to gestational age (r=-0.265, p=0.003) and weight at measurement (r=-0.269, p=0.002). Respiratory muscle function in ventilated newborns is negatively affected by prematurity and previous systemic or respiratory infection.

Continuous distending pressure for respiratory distress in preterm infants.

Respiratory distress syndrome (RDS) is the single most important cause of morbidity and mortality in preterm infants. In infants with progressive respiratory insufficiency, intermittent positive pressure ventilation (IPPV) with surfactant is the standard treatment for the condition, but it is invasive, potentially resulting in airway and lung injury. Continuous distending pressure (CDP) has been used for the prevention and treatment of RDS, as well as for the prevention of apnoea, and in weaning from IPPV. Its use in the treatment of RDS might reduce the need for IPPV and its sequelae. To determine the effect of continuous distending pressure (CDP) on the need for IPPV and associated morbidity in spontaneously breathing preterm infants with respiratory distress.Subgroup analyses were planned on the basis of birth weight (> or < 1000 or 1500 g), gestational age (groups divided at about 28 weeks and 32 weeks), methods of application of CDP (i.e. CPAP and CNP), application early versus late in the course of respiratory distress and high versus low pressure CDP and application of CDP in tertiary compared with non-tertiary hospitals, with the need for sensitivity analysis determined by trial quality.At the 2008 update, the objectives were modified to include preterm infants with respiratory failure. We used the standard search strategy of the Neonatal Review Group. This included searches of the Oxford Database of Perinatal Trials, the Cochrane Central Register of Controlled Trials (CENTRAL, 2015 Issue 4), MEDLINE (1966 to 30 April 2015) and EMBASE (1980 to 30 April 2015) with no language restriction, as well as controlled-trials.com, clinicaltrials.gov and the International Clinical Trials Registry Platform of the World Health Organization (WHO). All random or quasi-random trials of preterm infants with respiratory distress were eligible. Interventions were continuous distending pressure including continuous positive airway pressure (CPAP) by mask, nasal prong, nasopharyngeal tube or endotracheal tube, or continuous negative pressure (CNP) via a chamber enclosing the thorax and the lower body, compared with spontaneous breathing with oxygen added as necessary. We used standard methods of The Cochrane Collaboration and its Neonatal Review Group, including independent assessment of trial quality and extraction of data by each review author. We included six studies involving 355 infants - two using face mask CPAP, two CNP, one nasal CPAP and one both CNP (for less ill babies) and endotracheal CPAP (for sicker babies). For this update, we included no new trials.Continuous distending pressure (CDP) is associated with lower risk of treatment failure (death or use of assisted ventilation) (typical risk ratio (RR) 0.65, 95% confidence interval (CI) 0.52 to 0.81; typical risk difference (RD) -0.20, 95% CI -0.29 to -0.10; number needed to treat for an additional beneficial outcome (NNTB) 5, 95% CI 4 to 10; six studies; 355 infants), lower overall mortality (typical RR 0.52, 95% CI 0.32 to 0.87; typical RD -0.15, 95% CI -0.26 to -0.04; NNTB 7, 95% CI 4 to 25; six studies; 355 infants) and lower mortality in infants with birth weight above 1500 g (typical RR 0.24, 95% CI 0.07 to 0.84; typical RD -0.28, 95% CI -0.48 to -0.08; NNTB 4, 95% CI 2.00 to 13.00; two studies; 60 infants). Use of CDP is associated with increased risk of pneumothorax (typical RR 2.64, 95% CI 1.39 to 5.04; typical RD 0.10, 95% CI 0.04 to 0.17; number needed to treat for an additional harmful outcome (NNTH) 17, 95% CI 17.00 to 25.00; six studies; 355 infants). We found no difference in bronchopulmonary dysplasia (BPD), defined as oxygen dependency at 28 days (three studies, 260 infants), as well as no difference in outcome at nine to 14 years (one study, 37 infants). In preterm infants with respiratory distress, the application of CDP as CPAP or CNP is associated with reduced respiratory failure and mortality and an increased rate of pneumothorax. Four out of six of these trials were done in the 1970s. Therefore, the applicability of these results to current practice is difficult to assess. Further research is required to determine the best mode of administration.

Medida da freqüência respiratória e do volume corrente para prever a falha na extubação de recém-nascidos de muito baixo peso em ventilação mecânica

OBJETIVO: Verificar se a freqüência respiratória (FR), o volume corrente (VC) e a relação FR/VC poderiam prever a falha na extubação em recém-nascidos de muito baixo peso submetidos à ventilação mecânica. MÉTODOS: Estudo prospectivo, observacional, de recém-nascidos com idade gestacional &lt;37 semanas, peso ao nascer &lt;1.500g, ventilados desde o nascimento por 48 horas a 30 dias. Após a indicação da retirada da ventilação mecânica, o neonato foi colocado em pressão positiva contínua (CPAP) por via traqueal por dez minutos, avaliando-se FR, VC e relação FR/VC por meio de um pneumotacógrafo conectado entre a cânula traqueal e o circuito do ventilador. Em seguida, o recém-nascido foi extubado e colocado em CPAP nasal, considerando-se falha na extubação a necessidade de reintubação em 48 horas. RESULTADOS: Das 35 crianças estudadas, 20 (57%) foram extubadas com sucesso e 15 (43%) necessitaram de reintubação. A FR e a relação FR/VC tenderam a ser maiores no grupo que falhou na extubação; o VC foi similar nos dois grupos. A sensibilidade e a especificidade para falha na extubação foram, respectivamente, 50 e 67% para FR, 40 e 67% para o VC e 40 e 73% para a relação FR/VC. CONCLUSÕES: A FR, o VC e a relação FR/VC apresentaram baixa sensibilidade e especificidade para prever a falha na extubação em recém-nascidos de muito baixo peso.

Predicting successful extubation of very low birthweight infants

Objective: To determine the accuracy of three tests used to predict successful extubation of preterm infants. Study design: Mechanically ventilated infants with birth weight <1250 g and considered ready for...

32ndConferenceoftheEuropeanTeratologySociety

A brief period of endotracheal continuous positive airway pressure (ETT-CPAP) can predict extubation outcome but longer periods are associated with increased work of breathing and extubation failure. In ventilated preterm infants, brief ETT-CPAP does not increase the work of breathing and can be used to predict the outcome of extubation.

Extubation from low-rate intermittent positive airways pressure versus extubation after a trial of endotracheal continuous positive airways pressure in intubated preterm infants.

Failure of extubation and subsequent reintubation may result in additional stress and trauma to the premature infant. Testing infants about to be extubated with a period of endotracheal CPAP has been suggested as a method of demonstrating readiness for extubation. However, this process has been criticized as increasing the neonate's work of breathing and perhaps increasing the likelihood of extubation failure. In premature infants having their endotracheal tube removed, is direct extubation from low rate intermittent positive pressure ventilation (IPPV) more successful than that following a period of endotracheal continuous positive airway pressure (CPAP)? The standard search strategy of the Neonatal Review Group as outlined in the Cochrane Library was used. This included searches of the Oxford Database of Perinatal Trials, Cochrane Controlled Trials Register, MEDLINE, previous reviews including cross references, abstracts, conferences, symposia proceedings, expert informants and journal hand searching mainly in the English language. All trials using random or quasi-random allocation of premature infants to endotracheal CPAP or direct extubation following a period of IPPV were included. Data were extracted using standard methods of the Cochrane Collaboration and its Neonatal Review Group, with separate evaluation of trial quality and data extraction by each author and synthesis of data using relative risk. Direct extubation from low rate ventilation is associated with a trend to increased chance of successful extubation when compared to extubation after a period of endotracheal CPAP, RR 0.45 (0.19,1.07), RD -0.103 (-0.200,-0.006), NNT 10 (5,167). When only truly randomized trials are considered, this result becomes both statistically significant and clinically important, RR 0.10 (0.01,0.78), RD -0.201 (-0.319,-0.083), NNT 5 (3, 12). Similar differences are seen for the secondary outcome, apnea. Preterm infants no longer requiring endotracheal intubation and IPPV should be directly extubated without a trial of ETT CPAP.

Does continuous positive airway pressure (CPAP) during weaning from intermittent mandatory ventilation in very low birth weight infants have risks or benefits? A controlled trial

The purpose of this study was to evaluate three ventilator weaning strategies and to evaluate whether the use of continuous positive airway pressure (CPAP) via a nasopharyngeal or endotracheal tube would increase the likelihood of extubation failure in very low birth weight (VLBW) infants. We studied prospectively 87 preterm infants (mean +/- SD; birth weight: 1078 +/- 188 g; gestational age: 28.8 +/- 2.2 weeks) who were in the process of being weaned from intermittent mandatory ventilation (IMV). Infants were assigned by systematic sampling to one of the following three treatment groups: (1) direct extubation from IMV (D.EXT) (n = 30); (2) preextubation endotracheal CPAP (ET-CPAP) for 12-24 hr (n = 28); or (3) postextubation nasopharyngeal CPAP (NP-CPAP) for 12-24 hr (n = 29). Failure was defined as the need for resumption of mechanical ventilation within 72 hr of extubation due to frequent or severe apnea and/or respiratory failure (pH < 7.25, PaCO2 > 60 mm Hg, and/or requirement for oxygen FiO2 > 60%). There were no significant differences in failure rates among the three procedures. Failures were 2/30 (7%) in D.EXT; 4/28 (14%) in ET-CPAP; and 7/29 (24%) in the NP-CPAP. There were also no differences in FiO2, PaO2, and respiratory rates before and after discontinuation of IMV among the three groups. PaCO2 values were slightly higher in the NP-CPAP group 12-24 hr after weaning from IMV. We were unable to demonstrate a clear difference in extubation outcome by use of CPAP administered via an endotracheal or nasopharyngeal tube when compared to direct extubation from low-rate IMV in VLBW infants.

Successful Direct Extubation of Very Low Birth Weight Infants From Low Intermittent Mandatory Ventilation Rate

It is common practice to use endotracheal continuous positive airway pressure for various time periods up to 24 hours before attempting extubation in infants who are mechanically ventilated. A few studies in newborns have indicated that airway resistance is increased through small endotracheal tubes. This increases the work of breathing and the likelihood of subsequent ventilatory failure. In this study, 27 very low birth weight infants who were 1/2 to 28 days old at the time of extubation were randomly divided into two groups. One group of 13 study infants were extubated directly from intermittent mandatory ventilation rates of six to ten per minute, and the other 14 control infants were placed on continuous positive airway pressure through endotracheal tubes for six hours prior to an attempt to extubate. There was no difference between the two groups in gestational age, postnatal age, weight, or severity of lung disease at the time of extubation. All 13 study infants were successfully extubated without significant apnea or respiratory acidosis. Of the 14 control infants, only seven were successfully extubated; six infants had significant apnea and in one infant respiratory acidosis with pH 7.13 and PCO2 65 developed while receiving continuous positive airway pressure (13/13 v 7/14, P less than .005). The seven infants who failed the preextubation trial of continuous positive airway pressure were later extubated from low intermittent mandatory ventilation rates without significant apnea or respiratory acidosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of endotracheal continuous positive airway pressure on sensitivity to carbon dioxide and on respiratory timing in preterm infants

To determine the effects of continuous positive airway pressure (CPAP) on ventilatory response to CO2 and inspiratory and expiratory duration in preterm infants, 24 preterm infants with an average birth weight of 1220 g were studied at a mean age of 10.6 days. CPAP was applied via an uncuffed endotracheal tube. Testings were performed between ambient pressure and a positive airway pressure of 10 cm H2O. Approximately 2/3 of the applied pressure was transmitted to the esophagus. All infants demonstrated a ventilatory response to carbon dioxide of less than 50 ml/min per mm Hg Pco2 at ambient pressure, and no infant showed significant improvement at increasing levels of CPAP. Drive to breathe, as reflected in the inspiratory flow rate (Vt/Ti) also failed to change significantly. It may be concluded that in the apparent absence of significant changes in lung volume, CPAP fails to increase sensitivity to CO2 in preterm infants recovering from hyaline membrane disease.

FACTORS AFFECTING LUNG VOLUME IN POST EXTUBATED NEONATES

Extubated neonates previously treated with endotracheal continuous positive airway pressure (CPAP) maintain arterial oxygen tension (PaO2) and functional residual capacity (FRC) equivalent to values at 2-3 cm CPAP without alteration in inspired oxygen concentration. To determine the factors that maintain PaO2 and FRC after extubation we studied arterial blood gases, lung mechanics, and FRC in 15 neonates weighing 1.4 to 4.4 kg. Intraesophageal pressure, air flow, and tidal volume provided for calculation of lung compliance (CL), and lung inspiratory (RI) and expiratory (RE) resistance. Following extubation at zero CPAP, increases occurred in mean (± SEM) PaO2 from 59.3 (± 5.8) to 79.5 (± 4.0) mm Hg (P<0.05); FRC from 53.9 (± 6.0) to 67.3 (± 10.0) ml; RE from 148.0 (± 17.3) to 167.5 (± 25.7) cm H2O/L/second, and CL from 1.70 (± 0.33) to 2.09 (± 0.4) ml/cm H2O. I:E ratio decreased from 0.95 (± 0.05) at zero CPAP to 0.83 (± 0.07) after extubation (P<0.05). A significant correlation existed between FRC and expiratory resistance for all patients (P<0.01). No significant alterations occurred in PaCO2, base excess, minute ventilation, tidal volume, respiratory rate and heart rate. The changes in FRC with changes in expiratory resistance after extubation indicate that upper airway resistance, possibly at the laryngeal level may have a major role in maintenance of an adequate FRC after extubation.

Influence of lung inflation on respiratory control in neonates.

Influence of lung inflation on respiratory control in neonates.

Immediate effects of positive-pressure breathing on the ventilatary response to CO2.

ArticleImmediate effects of positive-pressure breathing on the ventilatary response to CO2.D C Flenley, L D Pengelly, and J Milic-EmiliD C Flenley, L D Pengelly, and J Milic-EmiliPublished Online:01 Jan 1971https://doi.org/10.1152/jappl.1971.30.1.7MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByObstructive sleep apnea syndrome and asthma: the role of continuous positive airway pressure treatmentAnnals of Allergy, Asthma & Immunology, Vol. 101, No. 4Differential Inspiratory Muscle Pressure Contributions to Breathing during Dynamic HyperinflationAmerican Journal of Respiratory and Critical Care Medicine, Vol. 156, No. 2Measurements of PEEP-Induced Changes in Lung VolumeChest, Vol. 112, No. 1The influence on the breathing pattern in man of moderate levels of continuous positive and negative airway pressure and of positive end-expiratory pressure during air and CO 2 inhalationActa Physiologica Scandinavica, Vol. 138, No. 3Breathing Responses to Imposed Mechanical Loads1 January 2011Load compensation during positive pressure breathing in anesthetized manRespiration Physiology, Vol. 65, No. 3Effect of endotracheal continuous positive airway pressure on sensitivity to carbon dioxide and on respiratory timing in preterm infantsPediatric Pulmonology, Vol. 2, No. 2Therapy of Hyaline Membrane DiseaseRESPIRATORY MUSCLES RESPONSE TO LOADINGMuscle activity during chest wall restriction and positive pressure breathing in manRespiration Physiology, Vol. 35, No. 3Current Therapy in Hyaline Membrane DiseaseClinics in Perinatology, Vol. 5, No. 2EFFECT OF CONTINUOUS POSITIVE AIRWAY PRESSURE BREATHING ON CARDIORESPIRATORY FUNCTION IN INFANTS WITH RESPIRATORY DISTRESS SYNDROMEActa Paediatrica, Vol. 66, No. 1Some Steady-State Effects of Respiratory LoadsChest, Vol. 70, No. 1Occlusion pressure as a measure of respiratory center output cm conscious manRespiration Physiology, Vol. 23, No. 2Immediate ventilatory response to elastic loads and positive pressure in manRespiration Physiology, Vol. 18, No. 3A New Stimulant for Ventilatory Failure?The Lancet, Vol. 301, No. 7806The Role of the Intrinsic Properties of the Respiratory Muscles in the Regulation of VentilationChest, Vol. 61, No. 2The role of the vagus nerves in the respiratory response to CO2 under hyperoxic conditionsPfl�gers Archiv European Journal of Physiology, Vol. 336, No. 2 More from this issue > Volume 30Issue 1January 1971Pages 7-11 https://doi.org/10.1152/jappl.1971.30.1.7PubMed4249901History Published online 1 January 1971 Published in print 1 January 1971 Metrics