Oxygen Therapy In Infants Research Articles

Family Integrated Care Shortens the Duration of Home Oxygen Therapy in Infants With Bronchopulmonary Dysplasia.

There have been few reports on whether family integrated care (FIC) can help premature infants with moderate to severe bronchopulmonary dysplasia (BPD) to shorten the duration of home oxygen therapy (HOT). To investigate the effect of FIC on the duration of HOT in premature infants with moderate to severe BPD. The subjects were retrospectively selected from premature infants with moderate to severe BPD in our center between June 2019 and December 2021. Patients were divided into the FIC group (n = 47) and the non-FIC group (n = 34). For univariate analysis, t test, Mann-Whitney U test, Pearson χ 2 test, or Fisher exact test was performed to explore the differences between the 2 groups. For multivariate analysis, simple and multiple linear regression was conducted to explore the effect of FIC on the duration of HOT. (1) The duration of HOT and length of stay after grouping were significantly shorter in the FIC group than in the non-FIC group ( P < .05). (2) The results of linear regression further revealed that FIC could significantly shorten the duration of HOT (simple linear regression, FIC [A] B : -12.709, 95% confidence interval (CI): -21.665 to -3.753; multiple linear regression, FIC [B] B : -11.419, 95% CI: -18.055 to -4.783). FIC improved the optimal target oxygen saturation ratio before discharge and shortened the duration of HOT in premature infants with moderate and severe BPD. FIC should be promoted in China's neonatal intensive care units, though it puts forward new requirements for nursing education and training.

Duration of monitoring after cessation of oxygen therapy in infants with bronchiolitis.

There is no evidence for how long bronchiolitis patients should be observed after coming off oxygen therapy and wide practice variation exists. We aimed to investigate whether it is safe to discharge bronchiolitis patients 4 h after cessation of oxygen therapy. A retrospective single-centre cohort study of 884 infants (n = 462 in 2018 vs. n = 422 in 2019) aged 0-24 months admitted with bronchiolitis in 2018 and 2019 was conducted after implementation of a bronchiolitis protocol recommending discharge home 4 h post-cessation of oxygen therapy in 2019. We compared the rate of readmissions and Clinical Reviews/Rapid Responses in the pre- and post-exposure cohorts. There was a significant reduction in median (interquartile range (IQR)) time to discharge post oxygen cessation by 87 min (510 (370-1033) min versus 423 (273-904) min; P < 0.001) and in median (IQR) length of stay by 6.7 h (2.11 (1.54-2.97) days vs. 1.83 (1.17-2.71) days; P < 0.001). There was no significant difference between readmissions in 2018 compared to 2019 (0.6% vs. 1.4%; P = 0.317). In 2018, there were two Clinical Reviews and in 2019 there were two Rapid Responses post-cessation of oxygen. There were 89 patients discharged within 4 h of cessation of oxygen therapy (n = 18 in 2018 vs. n = 71 in 2019; P < 0.001) with no readmissions, Clinical Reviews or Rapid Responses in the 2019 cohort. This study demonstrates that patients can be discharged 4 h after cessation of supplemental oxygen without increased risk of adverse events.

High flow nasal cannula for respiratory support in term infants.

High flow nasal cannula for respiratory support in term infants.

Outcome of HFNC Oxygen Therapy in Infants and Children Presenting in PICU with Acute Respiratory Distress

Outcome of HFNC Oxygen Therapy in Infants and Children Presenting in PICU with Acute Respiratory Distress

Association of Extubation Failure Rates With High-Flow Nasal Cannula, Continuous Positive Airway Pressure, and Bilevel Positive Airway Pressure vs Conventional Oxygen Therapy in Infants and Young Children

Extubation failure (EF) has been associated with worse outcomes in critically ill children. The relative efficacy of different modes of noninvasive respiratory support (NRS) to prevent EF is unknown. To study the reported relative efficacy of different modes of NRS (high-flow nasal cannula [HFNC], continuous positive airway pressure [CPAP], and bilevel positive airway pressure [BiPAP]) compared to conventional oxygen therapy (COT). MEDLINE, Embase, and CINAHL Complete through May 2022. Randomized clinical trials that enrolled critically ill children receiving invasive mechanical ventilation for more than 24 hours and compared the efficacy of different modes of postextubation NRS. Random-effects models were fit using a bayesian network meta-analysis framework. Between-group comparisons were estimated using odds ratios (ORs) or mean differences with 95% credible intervals (CrIs). Treatment rankings were assessed by rank probabilities and the surface under the cumulative rank curve (SUCRA). The primary outcome was EF (reintubation within 48 to 72 hours). Secondary outcomes were treatment failure (TF, reintubation plus NRS escalation or crossover to another NRS mode), pediatric intensive care unit (PICU) mortality, PICU and hospital length of stay, abdominal distension, and nasal injury. A total of 11 615 citations were screened, and 9 randomized clinical trials with a total of 1421 participants were included. Both CPAP and HFNC were found to be more effective than COT in reducing EF and TF (CPAP: OR for EF, 0.43; 95% CrI, 0.17-1.0 and OR for TF 0.27, 95% CrI 0.11-0.57 and HFNC: OR for EF, 0.64; 95% CrI, 0.24-1.0 and OR for TF, 0.34; 95% CrI, 0.16- 0.65). CPAP had the highest likelihood of being the best intervention for both EF (SUCRA, 0.83) and TF (SUCRA, 0.91). Although not statistically significant, BiPAP was likely to be better than COT for preventing both EF and TF. Compared to COT, CPAP and BiPAP were reported as showing a modest increase (approximately 3%) in nasal injury and abdominal distension. The studies included in this systematic review and network meta-analysis found that compared with COT, EF and TF rates were lower with modest increases in abdominal distension and nasal injury. Of the modes evaluated, CPAP was associated with the lowest rates of EF and TF.

Effect of Early High-Flow Nasal Oxygen vs Standard Oxygen Therapy on Length of Hospital Stay in Hospitalized Children With Acute Hypoxemic Respiratory Failure

Nasal high-flow oxygen therapy in infants with bronchiolitis and hypoxia has been shown to reduce the requirement to escalate care. The efficacy of high-flow oxygen therapy in children aged 1 to 4 years with acute hypoxemic respiratory failure without bronchiolitis is unknown. To determine the effect of early high-flow oxygen therapy vs standard oxygen therapy in children with acute hypoxemic respiratory failure. A multicenter, randomized clinical trial was conducted at 14 metropolitan and tertiary hospitals in Australia and New Zealand, including 1567 children aged 1 to 4 years (randomized between December 18, 2017, and March 18, 2020) requiring hospital admission for acute hypoxemic respiratory failure. The last participant follow-up was completed on March 22, 2020. Enrolled children were randomly allocated 1:1 to high-flow oxygen therapy (n = 753) or standard oxygen therapy (n = 764). The type of oxygen therapy could not be masked, but the investigators remained blinded until the outcome data were locked. The primary outcome was length of hospital stay with the hypothesis that high-flow oxygen therapy reduces length of stay. There were 9 secondary outcomes, including length of oxygen therapy and admission to the intensive care unit. Children were analyzed according to their randomization group. Of the 1567 children who were randomized, 1517 (97%) were included in the primary analysis (median age, 1.9 years [IQR, 1.4-3.0 years]; 732 [46.7%] were female) and all children completed the trial. The length of hospital stay was significantly longer in the high-flow oxygen group with a median of 1.77 days (IQR, 1.03-2.80 days) vs 1.50 days (IQR, 0.85-2.44 days) in the standard oxygen group (adjusted hazard ratio, 0.83 [95% CI, 0.75-0.92]; P < .001). Of the 9 prespecified secondary outcomes, 4 showed no significant difference. The median length of oxygen therapy was 1.07 days (IQR, 0.50-2.06 days) in the high-flow oxygen group vs 0.75 days (IQR, 0.35-1.61 days) in the standard oxygen therapy group (adjusted hazard ratio, 0.78 [95% CI, 0.70-0.86]). In the high-flow oxygen group, there were 94 admissions (12.5%) to the intensive care unit compared with 53 admissions (6.9%) in the standard oxygen group (adjusted odds ratio, 1.93 [95% CI, 1.35-2.75]). There was only 1 death and it occurred in the high-flow oxygen group. Nasal high-flow oxygen used as the initial primary therapy in children aged 1 to 4 years with acute hypoxemic respiratory failure did not significantly reduce the length of hospital stay compared with standard oxygen therapy. anzctr.org.au Identifier: ACTRN12618000210279.

Application Analysis of Accompanying Nursing Mode Combined with Health Education in Hyperbaric Oxygen Therapy for Infants with Hypoxic Ischemic Encephalopathy

To study application effect of accompanying nursing mode and health education on infants with hypoxic ischemic encephalopathy (HIE) treated with hyperbaric oxygen therapy (HBOT) via pure oxygen chamber. 124 cases of HIE infants treated with pure oxygen chamberHBOT admitted to our department (December 2018-December 2019) were chosen as the research samples, and split into experimental group and control group according to the order of admission, with 62 cases in each group. The control group received routine nursing while and the experimental group received accompanying nursing mode combined with health education to compare the mental development index (MDI), psychomotor development index (PDI), height, weight, neurological sequelae, efficacy and family members’ satisfaction with HBOT between the two groups. After nursing, MDI and PDI in experimental group were obviously higher compared with control group (P&lt;0.001);After nursing, the height and weight indexes in experimental group were obviously higher compared with control group (P&lt;0.05);After nursing, the total incidence of neurological sequelae in experimental group (3.2%) was obviously lower compared with control group (P&lt;0.05);After nursing, the total number of effective infants in experimental group was obviously higher compared with control group (P&lt;0.05);After nursing, the number of family members satisfied with HBOT in experimental group was obviously higher compared with control group (P&lt;0.05).The accompanying nursing mode combined with health education can greatly improve clinical indicators of HIE infants treated with pure oxygen chamber HBOT, promote their physical and mental development, and then improve the satisfaction of the family members with pure oxygen chamber HBOT, which should be promoted and applied in clinical practice as a high-quality nursing mode.

The starting rate for high-flow nasal cannula oxygen therapy in infants with bronchiolitis: Is clinical judgment enough?

To determine whether in infants with bronchiolitis admitted to a pediatric intensive care unit (PICU) the starting rate for high-flow nasal cannula (HFNC) therapy set by the attending physicians upon clinical judgment meets patients' peak inspiratory flow (PIF) demands and how it influences respiratory mechanics and breathing effort. We simultaneously obtained respiratory flow and esophageal pressure data from 31 young infants with moderate-to-severe bronchiolitis before and after setting the HFNC rate at 1 L/kg/min (HFNC-1), 2 L/kg/min (HFNC-2) or upon clinical judgment and compared data for PIF, respiratory mechanics, and breathing effort. Before HFNC oxygen therapy started, 16 (65%) infants had a PIF less than 1 L/kg/min (normal-PIF) and 15 (45%) had a PIF more than or equal to 1 L/kg/min (high-PIF). Normal-PIF-infants had higher airway resistance (p < .001) and breathing effort indexes (e.g., pressure rate product per min [PTP/min], p = .028) than high-PIF-infants. Starting the HFNC rate upon clinical judgment (1.20-2.05 L/kg/min) met all infants' PIFs. In normal-PIF-infants, the clinically judged flow rate increased PIF (p = .081) and tidal volume (p = .029), reduced airway resistance (p = .011), and intrinsic positive end-expiratory pressure (p = .041), whereas, in both high-PIF and normal-PIF infants, it decreased respiratory rate (p < .001) and indexes of breathing effort such as PTP/min (in normal-PIF infants, p = .004; in high-PIF infants, p = .001). The 2 L/kg/min but not 1 L/kg/min rate induced similar effects. The wide PIF distribution in our PICU population of infants with bronchiolitis suggests two disease phenotypes whose therapeutic options might differ. An initial flow rate of nearly 2 L/kg/min meets patients' flow demands and improves respiratory mechanics and breathing effort.

Application of a High-Flow Nasal Cannula for Prevention of Postextubation Atelectasis in Children Undergoing Surgery: A Randomized Controlled Trial.

General anesthesia-induced atelectasis is common, and persistent postoperative atelectasis is associated with pulmonary complications. We aimed to evaluate the preventive effects of a high-flow nasal cannula (HFNC) on postoperative atelectasis and respiratory complications in infants and small children. In this prospective randomized controlled trial, children (≤2 years) receiving general anesthesia (>2 hours) were randomized into the control and HFNC groups. At the end of the surgery, the first lung ultrasound evaluation was performed in both groups. In the postanesthetic care unit (PACU), the control group received conventional oxygen therapy, while the HFNC group received oxygen via HFNC, with a flow rate of 2 L kg-1 min-1. Before discharge to the ward, a second lung ultrasound examination was performed. The primary outcome was the lung ultrasound score at PACU discharge. The secondary outcomes included the lung ultrasound score at the end of surgery, the incidence of significant atelectasis at PACU discharge, and other postoperative outcomes. Lung ultrasound score and the incidence of atelectasis at the end of surgery did not differ significantly between the control (n = 38) and HFNC (n = 40) groups. After staying in the PACU, both groups showed a reduced lung ultrasound score and atelectasis incidence. However, the HFNC group had a significantly lower consolidation score than the control group (0; interquartile range [IQR] = 0-1 vs 3; IQR = 2-4; P< .001). Additionally, none of the patients had significant atelectasis in the HFNC group, compared to 6 patients in the control group (0% vs 15.8%; odds ratio [OR] = 0.444; 95% confidence interval for OR, 0.343-0.575; P = .011). Incidence of desaturation (oxygen saturation [Spo2] ≤ 95%), postoperative complications, and the length of hospital stay did not differ between the groups. Preventive use of HFNC after surgery improves the lung ultrasound score and reduces postoperative atelectasis compared to conventional oxygen therapy in infants and small children.

High-flow nasal cannula oxygen therapy in infants with acute lower respiratory tract infection. An experience in hospitals of the City of Buenos Aires.

During the winter, infants with acute lower respiratory tract infection (ALRTI) overburden health resources. In the Autonomous City of Buenos Aires, 35 000 children are seen at the hospitals every year; 8-10 % of them are admitted to the general hospitalization ward and 5-12 % of these, to the intensive care unit (ICU). In 2017, the Department of Maternal and Child Health of the Autonomous City of Buenos Aires included high flow nasal cannula (HNFC) oxygen therapy in the ALRTI protocol in the general ward of 3 hospitals. The objective of this study was to describe its outcomes and explore the potential factors related to therapeutic failure. Prospective, descriptive study with infants < 18 months old hospitalized due to ALRTI in 3 hospitals (Durand, Elizalde, Gutiérrez) between June and September 2017. All children unable to comply with low-flow therapeutic targets received HNFC oxygen therapy; admission to the ICU was considered a failure. Out of 522 patients hospitalized due to ALRTI, 39.7% required HNFC oxygen therapy. No significant baseline differences were observed between patients receiving HNFC and conventional oxygen therapy. Failure was observed in only 8.7% of patients with HNFC oxygen therapy. The decrease in respiratory rate was significantly greater and longer in patients with support success versus those with failure (p < 0.01). No complications were recorded. The implementation of HNFC oxygen therapy under a protocol in the general wards was a safe measure. Patients with therapeutic failure showed a smaller reduction in respiratory rate during treatment.

BET 1: High-flow nasal oxygen therapy in bronchiolitis

A shortcut review was carried out to establish whether high-flow nasal oxygen was better than standard oxygen therapy in infants with signs and symptoms of bronchiolitis at reducing the need...

Use of high-flow nasal cannula oxygen therapy in infants and children.

Heated, humidified high-flow nasal cannula (HHHFNC) therapy provides warmed, humidified oxygen to infants and children in respiratory distress at flow rates that deliver higher oxygen concentrations and some positive airway pressure compared with standard low-flow therapy. Increased use and experience is informing practice and establishing the benefits of HHHFNC use in a variety of clinical conditions. The focus of this practice point is to describe best practices for HHHFNC in (non- neonatal) paediatric patients with moderate-to-severe respiratory distress and to offer a safe, practical approach to oxygen delivery, and support.

Stress Oximetry: Description of a Test to Determine Readiness for Discontinuing Oxygen Therapy in Infants with Chronic Lung Disease.

Background In infants with CLD there are no objective tests to monitor an infant's progress towards weaning out of oxygen inhalation therapy (O2IT). A test involving staged maneuvers of increasing respiratory stress while decreasing oxygen support, termed Stress Oximetry (StressOx), has been used at our center for weaning O2IT. Objective To report the clinical utility of “StressOx” in evaluating readiness for discontinuing O2IT in infants with CLD. Methods A retrospective review was done of StressOx tests administered at our center from 2002-2008. StressOx was performed based on a consistent clinical protocol in all eligible infants on O2IT. O2IT was generally discontinued after infant had passed two StressOx tests and subsequently infants were monitored for a minimum of 7 days to determine successful weaning. Results There were 279 infants with 899 tests that met inclusion criteria. An average of 3 tests per infant was done, one week apart. The test had a specificity of 97.4% and a positive predictive value of 99.6% in determining success of discontinuing O2IT. Conclusions StressOx appears to be a clinically useful test that may help in determining an infant's ability to successfully wean out of O2IT. Further validation of this test is warranted.

A Randomized Trial of High-Flow Oxygen Therapy in Infants with Bronchiolitis: Franklin D, Babl FE, Schlapbach LJ, et al. N Engl J Med. 2018;378:1123-31

A Randomized Trial of High-Flow Oxygen Therapy in Infants with Bronchiolitis: Franklin D, Babl FE, Schlapbach LJ, et al. N Engl J Med. 2018;378:1123-31

A Randomized Trial of High-Flow Oxygen Therapy in Infants with Bronchiolitis

BackgroundHigh-flow oxygen therapy through a nasal cannula has been increasingly used in infants with bronchiolitis, despite limited high-quality evidence of its efficacy. The efficacy of high-flow oxygen therapy through a nasal cannula in settings other than intensive care units (ICUs) is unclear.MethodsIn this multicenter, randomized, controlled trial, we assigned infants younger than 12 months of age who had bronchiolitis and a need for supplemental oxygen therapy to receive either high-flow oxygen therapy (high-flow group) or standard oxygen therapy (standard-therapy group). Infants in the standard-therapy group could receive rescue high-flow oxygen therapy if their condition met criteria for treatment failure. The primary outcome was escalation of care due to treatment failure (defined as meeting ≥3 of 4 clinical criteria: persistent tachycardia, tachypnea, hypoxemia, and medical review triggered by a hospital early-warning tool). Secondary outcomes included duration of hospital stay, duration of oxygen therapy, and rates of transfer to a tertiary hospital, ICU admission, intubation, and adverse events.ResultsThe analyses included 1472 patients. The percentage of infants receiving escalation of care was 12% (87 of 739 infants) in the high-flow group, as compared with 23% (167 of 733) in the standard-therapy group (risk difference, −11 percentage points; 95% confidence interval, −15 to −7; P<0.001). No significant differences were observed in the duration of hospital stay or the duration of oxygen therapy. In each group, one case of pneumothorax (<1% of infants) occurred. Among the 167 infants in the standard-therapy group who had treatment failure, 102 (61%) had a response to high-flow rescue therapy.ConclusionsAmong infants with bronchiolitis who were treated outside an ICU, those who received high-flow oxygen therapy had significantly lower rates of escalation of care due to treatment failure than those in the group that received standard oxygen therapy. (Funded by the National Health and Medical Research Council and others; Australian and New Zealand Clinical Trials Registry number, ACTRN12613000388718.)

Benefits of the humidified low-flow oxygen therapy in infants with mild-moderate bronchiolitis.

To investigate the clinical benefits of using humidification in low-flow oxygen therapy. Specific objectives were to investigate via an assessment of the number of nasal lavages whether humidification can help to decrease the nasal mucus viscosity, to determine whether it can relieve feeding difficulties by comparing the weight gain in infants, to ascertain whether it can relieve respiratory distress by assessing the heart and respiratory rates and contribute to improved clinical outcomes, measured by the length of stay and oxygen requirements. There is no evidence to support the use of humidification in low-flow oxygen therapy as a usual clinical practice in the management of bronchiolitis. A controlled quasi-experimental study. A total of 97 infants were included, aged ≤6months, with bronchiolitis, low-flow oxygen therapy and bronchodilators nebulised with hypertonic saline 3%. Data from the control group (nonhumidified) were gathered from 2010-2012 (49 infants), and data from the group with humidification from 2012-2014 (48 infants). Linear and Poisson regressions were performed adjusting for relevant characteristics of patients. Humidification was shown to be associated with significant reductions in the number of nasal lavages in infants with Sant Joan de Déu Bronchiolitis Scores of BROSJOD≤7, in the heart rate of infants with mixed bronchodilators treatment, and in the length of stay and oxygen requirements of infants with Score BROSJOD≤5. No differences in weight and respiratory rate were found. Humidification in low-flow oxygen therapy is an effective nursing intervention to improve the clinical outcomes of infants with mild-moderate bronchiolitis. Humidifying the nasal mucosa can help to reduce the need for professional procedures, oxygen requirements and hospitalisation length. Further research into the economic savings involved is recommended.

Humidified high flow nasal cannula oxygen therapy in acute bronchiolitis

Background: Bronchiolitis is a major cause of morbidity and leading cause of hospitalization, mostly in early childhood without coexisting illnesses. Traditionally dry oxygen is provided at 100% concentration via low flow nasal prongs. However, the latest studies have revealed that oxygen therapy via heated, humidified, high flow nasal cannula (HFNC) allows the delivery of high inspired gas flows which is better than the traditional one. Methods: All previously healthy children between 1 and 24 months of age with an established clinical diagnosis of moderate to severe bronchiolitis (clinical severity score ?4) were enrolled for study. The patients were divided into two groups: Patients in Group 1 received HFNC oxygen therapy (HFNC group) while those in Group 2 received conventional oxygen therapy (non-HFNC group). The patients were randomized in each arm by simple randomization. Outcome parameters measured were duration of hospital stay, duration of pediatric intensive care unit (PICU) stay, oxygen saturation (SPO2), respiratory rate, adverse event (respiratory failure), need for intermittent positive pressure ventilation or continuous positive airway pressure. Results: Out of 100 patients studied, 50 received HFNC oxygen and 50 received conventional oxygen. There was early and better improvement in SPO2 and respiratory rate (p&lt;0.001), decreased length of hospital stay (p&lt;0.001) and PICU stay (p&lt;0.01) among the patients in HFNC group as compared to non-HFNC group. The most common adverse event during the hospital course was respiratory failure which was seen among 4 patients in non-HFNC group and none among HFNC group developed such complication. Conclusion: The use of HFNC oxygen therapy in infants hospitalized with acute bronchiolitis reduces PICU and hospital stay as well as the potential complications which will substantially reduce the hospital cost.

Observed-to-expected MRI fetal lung volume can predict long-term lung morbidity in infants with congenital diaphragmatic hernia

Objective: Congenital diaphragmatic hernia (CDH) causes pulmonary hypoplasia and pulmonary hypertension, which are associated with long-term respiratory problems in infants. The aim of this study was to establish a marker for predicting lung function at 1 year of age in infants with CDH.Materials and methods: Infants with isolated CDH who were delivered after 35 weeks of gestation from April 2008 to June 2016 at Nagoya University Hospital were registered. Regarding alive infants with CDH, only those who underwent follow-up for at least 1 year were registered. Finally, 48 infants were analyzed in this study.Results: Gestational age at diagnosis, amniotic lamellar body count at birth, observed-to-expected MRI fetal lung volume (percent FLV), liver herniation, and polyhydramnios were found to be significant parameters for predicting mortality in infants with CDH. Regarding alive infants with CDH, percent FLV was the only significant parameter to predict need for oxygen therapy at 1 year of age (p < .05). There was a significant negative correlation between percent FLV and duration of oxygen therapy in infants with CDH (r = .516, p < .001).Conclusions: Percent FLV is a useful predictor of long-term lung morbidity in infants with CDH.

Hypoxic pulmonary vasoconstriction, carotid body function and erythropoietin production in adult rats perinatally exposed to hyperoxia.

Adult animals that have been perinatally exposed to oxygen-rich atmospheres (hyperoxia), recalling those used for oxygen therapy in infants, exhibit a loss of hypoxic pulmonary vasoconstriction, whereas vasoconstriction elicited by depolarizing agents is maintained. Loss of pulmonary hypoxic vasoconstriction is not linked to alterations in oxygen-sensitive K(+) currents in pulmonary artery smooth muscle cells. Loss of hypoxic vasoconstriction is associated with early postnatal oxidative damage and corrected by an antioxidant diet. Perinatal hyperoxia damages carotid body chemoreceptor cell function and the antioxidant diet does not reverse it. The hypoxia-elicited increase in erythropoietin plasma levels is not affected by perinatal hyperoxia. The potential clinical significance of the findings in clinical situations such as pneumonia, chronic obstructive pulmonary disease or general anaesthesia is considered. Adult mammalians possess three cell systems that are activated by acute bodily hypoxia: pulmonary artery smooth muscle cells (PASMC), carotid body chemoreceptor cells (CBCC) and erythropoietin (EPO)-producing cells. In rats, chronic perinatal hyperoxia causes permanent carotid body (CB) atrophy and functional alterations of surviving CBCC. There are no studies on PASMC or EPO-producing cells. Our aim is to define possible long-lasting functional changes in PASMC or EPO-producing cells (measured as EPO plasma levels) and, further, to analyse CBCC functional alterations. We used 3- to 4-month-old rats born and reared in a normal atmosphere or exposed to perinatal hyperoxia (55-60% O2 for the last 5-6days of pregnancy and 4weeks after birth). Perinatal hyperoxia causes an almost complete loss of hypoxic pulmonary vasoconstriction (HPV), which was correlated with lung oxidative status in early postnatal life and prevented by antioxidant supplementation in the diet. O2 -sensitivity of K(+) currents in the PASMC of hyperoxic animals is normal, indicating that their inhibition is not sufficient to trigger HPV. Perinatal hyperoxia also abrogated responses elicited by hypoxia on catecholamine and cAMP metabolism in the CB. An increase in EPO plasma levels elicited by hypoxia was identical in hyperoxic and control animals, implying a normal functioning of EPO-producing cells. The loss of HPV observed in adult rats and caused by perinatal hyperoxia, comparable to oxygen therapy in premature infants, might represent a previously unrecognized complication of such a medical intervention capable of aggravating medical conditions such as regional pneumonias, atelectases or general anaesthesia in adult life.

G118(P) Weaning Home Oxygen Therapy in Infants with Chronic Lung Disease of Prematurity

BackgroundCurrently there are no evidence based guidelines to standardise the process of weaning home oxygen therapy in infants with chronic lung disease of prematurity (CLDP). Weaning decisions are based on...