Nasopharyngeal oxygen therapy produces positive end-expiratory pressure in infants

High flow nasal cannula for respiratory support in term infants

BACKGROUND

Respiratory failure or respiratory distress in infants is the most common reason for non-elective admission to hospitals and neonatal intensive care units. Non-invasive methods of respiratory support have become the preferred mode of treating respiratory problems as they avoid some of the complications associated with intubation and mechanical ventilation. High flow nasal cannula (HFNC) therapy is increasingly being used as a method of non-invasive respiratory support. However, the evidence pertaining to its use in term infants (defined as infants ≥ 37 weeks gestational age to the end of the neonatal period (up to one month postnatal age)) is limited and there is no consensus of opinion regarding the safety and efficacy HFNC in this population.

OBJECTIVES

To assess the safety and efficacy of high flow nasal cannula oxygen therapy for respiratory support in term infants when compared with other forms of non-invasive respiratory support.

SEARCH METHODS

We searched the following databases in December 2022: Cochrane CENTRAL; PubMed; Embase; CINAHL; LILACS; Web of Science; Scopus. We also searched the reference lists of retrieved studies and performed a supplementary search of Google Scholar.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that investigated the use of high flow nasal cannula oxygen therapy in infants ≥ 37 weeks gestational age up to one month postnatal age (the end of the neonatal period).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility, performed data extraction, and assessed risk of bias in the included studies. Where studies were sufficiently similar, we performed a meta-analysis using mean differences (MD) for continuous data and risk ratios (RR) for dichotomous data, with their respective 95% confidence intervals (CIs). For statistically significant RRs, we calculated the number needed to treat for an additional beneficial outcome (NNTB). We used the GRADE approach to evaluate the certainty of the evidence for clinically important outcomes.

MAIN RESULTS

We included eight studies (654 participants) in this review. Six of these studies (625 participants) contributed data to our primary analyses. Four studies contributed to our comparison of high flow nasal cannula (HFNC) oxygen therapy versus continuous positive airway pressure (CPAP) for respiratory support in term infants. The outcome of death was reported in two studies (439 infants) but there were no events in either group. HFNC may have little to no effect on treatment failure, but the evidence is very uncertain (RR 0.98, 95% CI 0.47 to 2.04; 3 trials, 452 infants; very low-certainty evidence). The outcome of chronic lung disease (need for supplemental oxygen at 28 days of life) was reported in one study (375 participants) but there were no events in either group. HFNC may have little to no effect on the duration of respiratory support (any form of non-invasive respiratory support with or without supplemental oxygen), but the evidence is very uncertain (MD 0.17 days, 95% CI -0.28 to 0.61; 4 trials, 530 infants; very low-certainty evidence). HFNC likely results in little to no difference in the length of stay at the intensive care unit (ICU) (MD 0.90 days, 95% CI -0.31 to 2.12; 3 trials, 452 infants; moderate-certainty evidence). HFNC may reduce the incidence of nasal trauma (RR 0.16, 95% CI 0.04 to 0.66; 1 trial, 78 infants; very low-certainty evidence) and abdominal overdistension (RR 0.22, 95% CI 0.07 to 0.71; 1 trial, 78 infants; very low-certainty evidence), but the evidence is very uncertain. Two studies contributed to our analysis of HFNC versus low flow nasal cannula oxygen therapy (LFNC) (supplemental oxygen up to a maximum flow rate of 2 L/min). The outcome of death was reported in both studies (95 infants) but there were no events in either group. The evidence suggests that HFNC may reduce treatment failure slightly (RR 0.44, 95% CI 0.21 to 0.92; 2 trials, 95 infants; low-certainty evidence). Neither study reported results for the outcome of chronic lung disease (need for supplemental oxygen at 28 days of life). HFNC may have little to no effect on the duration of respiratory support (MD -0.07 days, 95% CI -0.83 to 0.69; 1 trial, 74 infants; very low-certainty evidence), length of stay at the ICU (MD 0.49 days, 95% CI -0.83 to 1.81; 1 trial, 74 infants; very low-certainty evidence), or hospital length of stay (MD -0.60 days, 95% CI -2.07 to 0.86; 2 trials, 95 infants; very low-certainty evidence), but the evidence is very uncertain. Adverse events was an outcome reported in both studies (95 infants) but there were no events in either group. The risk of bias across outcomes was generally low, although there were some concerns of bias. The certainty of evidence across outcomes ranged from moderate to very low, downgraded due to risk of bias, imprecision, indirectness, and inconsistency.

AUTHORS' CONCLUSIONS

When compared with CPAP, HFNC may result in little to no difference in treatment failure. HFNC may have little to no effect on the duration of respiratory support, but the evidence is very uncertain. HFNC likely results in little to no difference in the length of stay at the intensive care unit. HFNC may reduce the incidence of nasal trauma and abdominal overdistension, but the evidence is very uncertain. When compared with LFNC, HFNC may reduce treatment failure slightly. HFNC may have little to no effect on the duration of respiratory support, length of stay at the ICU, or hospital length of stay, but the evidence is very uncertain. There is insufficient evidence to enable the formulation of evidence-based guidelines on the use of HFNC for respiratory support in term infants. Larger, methodologically robust trials are required to further evaluate the possible health benefits or harms of HFNC in this patient population.

Effect of randomization of nasal high flow rate in preterm infants

OBJECTIVE

To assess the effect of nasal high flow (NHF) cannula on end-expiratory level (EEL), continuous distending pressure (CDP) and regional ventilation distribution in preterm infants.

DESIGN

A prospective observational clinical study with randomly applied NHF rates.

PATIENTS AND SETTING

Preterm infants requiring continuous positive airway pressure (CPAP) respiratory support in a Neonatal Intensive Care Unit.

INTERVENTIONS

Infants were measured on randomly applied flow rates at 2, 4, and 6 L/min of NHF and compared with bubble CPAP.

MEASUREMENTS AND RESULTS

Regional ventilation distribution and EEL were measured using electrical impedance tomography (EIT) and respiratory inductance plethysmography (RIP) in 24 preterm infants (31.19 ± 1.17 weeks corrected age). Changes in CDP were measured from the esophagus via the nasogastric tube. Physiological variables were also recorded. There were no differences in ventilation distribution, EEL or CDP between CPAP and NHF (P > .05). However, the physiological variables of FiO₂ (P = .01) and SpO₂ /FiO₂ (P < .01) were improved on CPAP compared with NHF.

CONCLUSION

NHF applied in random order with flow rates between 2 to 6 L/min was equally as good as CPAP in maintaining EEL and ventilation distribution in stable preterm infants. Overall oxygenation was better on CPAP compared to NHF.

New Methods for Noninvasive Oxygen Administration

Oxygen therapy is an essential part of neonatal care. Targeting oxygen saturations and preventing hypoxemia and hyperoxemia is difficult, particularly in preterm infants. The mode of oxygen delivery directly affects the stability of oxygen saturations, hypoxemia, and hyperoxemia. This stability has important clinical implications. New methods of noninvasive oxygen administration, including closed-loop automated control and servo-controlled oxygen environments, have been developed to improve oxygen saturation targeting and decrease episodes of hyperoxemia and hypoxemia.

Bubble CPAP devices for infants and children in resource-limited settings: review of the literature

Background: Early management of respiratory distress is critical to reducing mortality in infants and children in resource-limited settings. Bubble continuous positive airway pressure (bCPAP) can offer effective and affordable non-invasive respiratory support. Objective: To determine the best physical components of bubble CPAP circuits for respiratory support of children in low-resource settings. Methods: Using PubMed, CINAHL and LILACS, studies of any design in any language published before June 2017 which examined the physical components of bCPAP circuits were identified and reviewed. Results: After screening, the review included 45 articles: 17 clinical trials, 11 literature reviews, 10 technical assessments of bCPAP components, three reports of real-world implementation in low-resource settings, three cost analyses and one case report. There is no ideal bCPAP circuit for all settings and patients, but some choices are generally better than others in designing a circuit for low-resource settings. Oxygen concentrators are usually the best source of oxygen. As yet, there is no affordable and accurate oxygen blender. Nasal prongs are the simplest patient interface to use with the fewest complications but are not the cheapest option. Expiratory limbs should be at least 1 cm in diameter. Home-made pressure generators are effective, safe and affordable. Conclusion: This narrative review found many studies which evaluated the real clinical outcomes with bCPAP in the target population as well as technical comparison of bCPAP components. However, many studies were not blinded or randomised and there was significant heterogeneity in design and outcome measures. Abbreviations: bCPAP, bubble continuous positive airway pressure; CPAP, continuous positive airway pressure; FiO₂, fractional oxygen concentration; HFNC, high-flow nasal cannula; HIC, high-income countries; LMIC, low- and middle-income countries; NP, nasopharyngeal; O₂, oxygen; PEEP, positive end-expiratory pressure; PICO, Population, Intervention, Comparison and Outcome.

The effects of nasal continuous positive airway pressure and high flow nasal cannula on heart rate variability in extremely preterm infants after extubation: A randomized crossover trial

BACKGROUND

NCPAP and High flow nasal cannula (HFNC) are common modes of non-invasive respiratory support used after extubation. Heart rate variability (HRV) has been demonstrated as a marker of well-being in neonates and differences in HRV were described in preterm infants receiving respiratory care. The objective was to investigate the effects of NCPAP and HFNC on HRV after extubation.

METHODS

Randomized crossover trial in infants with birth weight (BW) ≤1250 g after undergoing their first elective extubation. ECG recordings were performed during 45 min while on HFNC and nasal continuous positive airway pressure (NCPAP). Time domain, non-linear, and frequency domain parameters were calculated and compared during HFNC and NCPAP using paired nonparametric tests. A secondary analysis was performed in the subgroup of infants that were successfully extubated.

RESULTS

Thirty infants with median [range] gestational age of 27 weeks [24.1-29.3] and BW of 930 g [610-1220] were studied at 5 days [1-39] of age. No differences in HRV parameters were observed between HFNC and NCPAP. In the secondary analysis, infants successfully extubated (n = 27) had a significantly higher HRV during HFNC for some time domain parameters. For instance, the standard deviation of the RR intervals (SDRR) was more likely to be higher during HFNC compared to NCPAP (HFNC: 18/27 vs NCPAP: 9/27, P = 0.017) .

CONCLUSION

During the first hours after extubation, no differences in HRV were detected between HFNC and NCPAP in the overall cohort. However, a significantly higher HRV was noted during HFNC in the subgroup of infants successfully extubated.

Children's Oxygen Administration Strategies Trial (COAST): A randomised controlled trial of high flow versus oxygen versus control in African children with severe pneumonia

Background: In Africa, the clinical syndrome of pneumonia remains the leading cause of morbidity and mortality in children in the post-neonatal period. This represents a significant burden on in-patient services. The targeted use of oxygen and simple, non-invasive methods of respiratory support may be a highly cost-effective means of improving outcome, but the optimal oxygen saturation threshold that results in benefit and the best strategy for delivery are yet to be tested in adequately powered randomised controlled trials. There is, however, an accumulating literature about the harms of oxygen therapy across a range of acute and emergency situations that have stimulated a number of trials investigating permissive hypoxia. Methods: In 4200 African children, aged 2 months to 12 years, presenting to 5 hospitals in East Africa with respiratory distress and hypoxia (oxygen saturation < 92%), the COAST trial will simultaneously evaluate two related interventions (targeted use of oxygen with respect to the optimal oxygen saturation threshold for treatment and mode of delivery) to reduce shorter-term mortality at 48-hours (primary endpoint), and longer-term morbidity and mortality to 28 days in a fractional factorial design, that compares: Liberal oxygenation (recommended care) compared with a strategy that permits hypoxia to SpO 2 > or = 80% (permissive hypoxia); andHigh flow using AIrVO 2 TM compared with low flow delivery (routine care). Discussion: The overarching objective is to address the key research gaps in the therapeutic use of oxygen in resource-limited setting in order to provide a better evidence base for future management guidelines. The trial has been designed to address the poor outcomes of children in sub-Saharan Africa, which are associated with high rates of in-hospital mortality, 9-10% (for those with oxygen saturations of 80-92%) and 26-30% case fatality for those with oxygen saturations <80%. Clinical trial registration: ISRCTN15622505 Trial status: Recruiting.

Children's Oxygen Administration Strategies Trial (COAST): A randomised controlled trial of high flow versus oxygen versus control in African children with severe pneumonia

Background: In Africa, the clinical syndrome of pneumonia remains the leading cause of morbidity and mortality in children in the post-neonatal period. This represents a significant burden on in-patient services. The targeted use of oxygen and simple, non-invasive methods of respiratory support may be a highly cost-effective means of improving outcome, but the optimal oxygen saturation threshold that results in benefit and the best strategy for delivery are yet to be tested in adequately powered randomised controlled trials. There is, however, an accumulating literature about the harms of oxygen therapy across a range of acute and emergency situations that have stimulated a number of trials investigating permissive hypoxia. Methods: In 4200 African children, aged 2 months to 12 years, presenting to 5 hospitals in East Africa with respiratory distress and hypoxia (oxygen saturation < 92%), the COAST trial will simultaneously evaluate two related interventions (targeted use of oxygen with respect to the optimal oxygen saturation threshold for treatment and mode of delivery) to reduce shorter-term mortality at 48-hours (primary endpoint), and longer-term morbidity and mortality to 28 days in a fractional factorial design, that compares: Liberal oxygenation (recommended care) compared with a strategy that permits hypoxia to SpO 2 > or = 80% (permissive hypoxia); andHigh flow using AIrVO 2TM compared with low flow delivery (routine care). Discussion: The overarching objective is to address the key research gaps in the therapeutic use of oxygen in resource-limited setting in order to provide a better evidence base for future management guidelines. The trial has been designed to address the poor outcomes of children in sub-Saharan Africa, which are associated with high rates of in-hospital mortality, 9-10% (for those with oxygen saturations of 80-92%) and 26-30% case fatality for those with oxygen saturations <80%. Clinical trial registration: ISRCTN15622505 Trial status: Recruiting.

Physiology of non-invasive respiratory support

Non-invasive ventilation (NIV) is used in neonates to treat extrathoracic and intrathoracic airway obstruction, parenchymal lung disease and disorders of control of breathing. Avoidance of airway intubation is associated with a reduction in the incidence of chronic lung disease among preterm infants with respiratory distress syndrome. Use of nasal continuous positive airway pressure (nCPAP) may help establish and maintain functional residual capacity (FRC), decrease respiratory work, and improve gas exchange. Other modes of non-invasive ventilation, which include heated humidified high-flow nasal cannula therapy (HHHFNC), nasal intermittent mandatory ventilation (NIMV), non-invasive pressure support ventilation (NI-PSV), and bi-level CPAP (SiPAP™), have also been shown to provide additional benefit in improving breathing patterns, reducing work of breathing, and increasing gas exchange when compared with nCPAP. Newer modes, such as neurally adjusted ventilatory assist (NAVA), hold the promise of improving patient-ventilator synchrony and so might ultimately improve outcomes for preterm infants with respiratory distress.

High flow nasal cannula for respiratory support in preterm infants

BACKGROUND

High flow nasal cannulae (HFNC) are small, thin, tapered binasal tubes that deliver oxygen or blended oxygen/air at gas flows of more than 1 L/min. HFNC are increasingly being used as a form of non-invasive respiratory support for preterm infants.

OBJECTIVES

To compare the safety and efficacy of HFNC with other forms of non-invasive respiratory support in preterm infants.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 1), MEDLINE via PubMed (1966 to 1 January 2016), EMBASE (1980 to 1 January 2016), and CINAHL (1982 to 1 January 2016). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised or quasi-randomised trials comparing HFNC with other non-invasive forms of respiratory support in preterm infants immediately after birth or following extubation.

DATA COLLECTION AND ANALYSIS

The authors extracted and analysed data, and calculated risk ratio, risk difference and number needed to treat for an additional beneficial outcome.

MAIN RESULTS

We identified 15 studies for inclusion in the review. The studies differed in the interventions compared (nasal continuous positive airway pressure (CPAP), nasal intermittent positive pressure ventilation (NIPPV), non-humidified HFNC, models for delivering HFNC), the gas flows used and the indications for respiratory support (primary support from soon after birth, post-extubation support, weaning from CPAP support). When used as primary respiratory support after birth compared to CPAP (4 studies, 439 infants), there were no differences in the primary outcomes of death (typical risk ratio (RR) 0.36, 95% CI 0.01 to 8.73; 4 studies, 439 infants) or chronic lung disease (CLD) (typical RR 2.07, 95% CI 0.64 to 6.64; 4 studies, 439 infants). HFNC use resulted in longer duration of respiratory support, but there were no differences in other secondary outcomes. One study (75 infants) showed no differences between HFNC and NIPPV as primary support. Following extubation (total 6 studies, 934 infants), there were no differences between HFNC and CPAP in the primary outcomes of death (typical RR 0.77, 95% CI 0.43 to 1.36; 5 studies, 896 infants) or CLD (typical RR 0.96, 95% CI 0.78 to 1.18; 5 studies, 893 infants). There was no difference in the rate of treatment failure (typical RR 1.21, 95% CI 0.95 to 1.55; 5 studies, 786 infants) or reintubation (typical RR 0.91, 95% CI 0.68 to 1.20; 6 studies, 934 infants). Infants randomised to HFNC had reduced nasal trauma (typical RR 0.64, 95% CI 0.51 to 0.79; typical risk difference (RD) -0.14, 95% CI -0.20 to -0.08; 4 studies, 645 infants). There was a small reduction in the rate of pneumothorax (typical RR 0.35, 95% CI 0.11 to 1.06; typical RD -0.02, 95% CI -0.03 to -0.00; 5 studies 896 infants) in infants treated with HFNC. Subgroup analysis found no difference in the rate of the primary outcomes between HFNC and CPAP in preterm infants in different gestational age subgroups, though there were only small numbers of extremely preterm and late preterm infants. One trial (28 infants) found similar rates of reintubation for humidified and non-humidified HFNC, and two other trials (100 infants) found no difference between different models of equipment used to deliver humidified HFNC. For infants weaning from non-invasive respiratory support (CPAP), two studies (149 infants) found that preterm infants randomised to HFNC had a reduced duration of hospitalisation compared with infants who remained on CPAP.

AUTHORS' CONCLUSIONS

HFNC has similar rates of efficacy to other forms of non-invasive respiratory support in preterm infants for preventing treatment failure, death and CLD. Most evidence is available for the use of HFNC as post-extubation support. Following extubation, HFNC is associated with less nasal trauma, and may be associated with reduced pneumothorax compared with nasal CPAP. Further adequately powered randomised controlled trials should be undertaken in preterm infants comparing HFNC with other forms of primary non-invasive support after birth and for weaning from non-invasive support. Further evidence is also required for evaluating the safety and efficacy of HFNC in extremely preterm and mildly preterm subgroups, and for comparing different HFNC devices.

Bubble continuous positive airway pressure for children with severe pneumonia and hypoxaemia in Bangladesh: an open, randomised controlled trial

BACKGROUND

In developing countries, mortality in children with very severe pneumonia is high, even with the provision of appropriate antibiotics, standard oxygen therapy, and other supportive care. We assessed whether oxygen therapy delivered by bubble continuous positive airway pressure (CPAP) improved outcomes compared with standard low-flow and high-flow oxygen therapies.

METHODS

This open, randomised, controlled trial took place in Dhaka Hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh. We randomly assigned children younger than 5 years with severe pneumonia and hypoxaemia to receive oxygen therapy by either bubble CPAP (5 L/min starting at a CPAP level of 5 cm H2O), standard low-flow nasal cannula (2 L/min), or high-flow nasal cannula (2 L/kg per min up to the maximum of 12 L/min). Randomisation was done with use of the permuted block methods (block size of 15 patients) and Fisher and Yates tables of random permutations. The primary outcome was treatment failure (ie, clinical failure, intubation and mechanical ventilation, death, or termination of hospital stay against medical advice) after more than 1 h of treatment. Primary and safety analyses were by intention to treat. We did two interim analyses and stopped the trial after the second interim analysis on Aug 3, 2013, as directed by the data safety and monitoring board. This trial is registered at ClinicalTrials.gov, number NCT01396759.

FINDINGS

Between Aug 4, 2011, and July 17, 2013, 225 eligible children were recruited. We randomly allocated 79 (35%) children to receive oxygen therapy by bubble CPAP, 67 (30%) to low-flow oxygen therapy, and 79 (35%) to high-flow oxygen therapy. Treatment failed for 31 (14%) children, of whom five (6%) had received bubble CPAP, 16 (24%) had received low-flow oxygen therapy, and ten (13%) had received high-flow oxygen therapy. Significantly fewer children in the bubble CPAP group had treatment failure than in the low-flow oxygen therapy group (relative risk [RR] 0·27, 99·7% CI 0·07-0·99; p=0·0026). No difference in treatment failure was noted between patients in the bubble CPAP and those in the high-flow oxygen therapy group (RR 0·50, 99·7% 0·11-2·29; p=0·175). 23 (10%) children died. Three (4%) children died in the bubble CPAP group, ten (15%) children died in the low-flow oxygen therapy group, and ten (13%) children died in the high-flow oxygen therapy group. Children who received oxygen by bubble CPAP had significantly lower rates of death than the children who received oxygen by low-flow oxygen therapy (RR 0·25, 95% CI 0·07-0·89; p=0·022).

INTERPRETATION

Oxygen therapy delivered by bubble CPAP improved outcomes in Bangladeshi children with very severe pneumonia and hypoxaemia compared with standard low-flow oxygen therapy. Use of bubble CPAP oxygen therapy could have a large effect in hospitals in developing countries where the only respiratory support for severe childhood pneumonia and hypoxaemia is low-flow oxygen therapy. The trial was stopped early because of higher mortality in the low-flow oxygen group than in the bubble CPAP group, and we acknowledge that the early cessation of the trial reduces the certainty of the findings. Further research is needed to test the feasibility of scaling up bubble CPAP in district hospitals and to improve bubble CPAP delivery technology.

FUNDING

International Centre for Diarrhoeal Disease Research, Bangladesh, and Centre for International Child Health, University of Melbourne.

A novel technique of non-invasive ventilation: Pharyngeal oxygen with nose-closure and abdominal-compression--Aid for pediatric flexible bronchoscopy

OBJECTIVE

To evaluate the safety, feasibility and efficacy of a novel non-invasive ventilation (NIV) technique--pharyngeal oxygen with nose-closure and abdominal-compression (PhO2 -NC-AC)--to aid pediatric flexible bronchoscopy (FB).

DESIGN

A prospective 1 year study of patients who received FB. A basic PhO2 flow (0.5-1.0 L/kg/min, maximal 5.0 L/min) was routinely applied. Active NIV was initiated when the heart rate dropped <80 beats/min or desaturation was <80% for >10 sec. It was performed as follows: NC 1 sec for inspiration then released, followed by AC 1 sec for active expiration at a rate of 20-30 cycles/min until vital signs returned to acceptable levels for >10 sec. When the patients were stable, supplementary NIV was optionally given. Cardiopulmonary parameters were collected and analyzed.

MEASUREMENTS AND MAIN RESULTS

Three hundred thirty-seven FBs, including 188 therapeutic, were conducted in 286 patients with a mean age of 18.3 months (± 14.4, 10 min to 12 years) and a mean body weight of 13.5 kg (± 6.7, 0.5-35 kg). Three hundred thirty-three active NIVs were executed with a mean duration of 87.8 sec (± 40.4, 28-190 sec). A significantly longer FB duration (33.2 ± 16.7 min vs. 7.2 ± 2.8 min, P < 0.001) and a higher application rate of active NIV (1.44/FB vs. 0.42/FB) were noted in the therapeutic compared to the diagnostic group. Vital signs and blood gases (35 cases) improved rapidly and returned to baseline within 3 min. All FBs were safely and successfully completed without significant complications.

CONCLUSIONS

PhO2 -NC-AC is a simple, safe and effective NIV technique for respiratory support and rescue during various pediatric FB procedures.

Physiologic effect of high-flow nasal cannula in infants with bronchiolitis

OBJECTIVE

To assess the effect of delivering high-flow nasal cannula flow on end-expiratory lung volume, continuous distending pressure, and regional ventilation distribution in infants less than 12 months old with bronchiolitis.

DESIGN

Prospective observational clinical study.

SETTING

Nineteen bed medical and surgical PICU.

PATIENTS

Thirteen infants with bronchiolitis on high-flow nasal therapy.

INTERVENTIONS

The study infants were measured on a flow rate applied at 2 and 8 L/min through the high-flow nasal cannula system.

MEASUREMENTS AND RESULTS

Ventilation distribution was measured with regional electrical impedance amplitudes and end-expiratory lung volume using electrical impedance tomography. Changes in continuous distending pressure were measured from the esophagus via the nasogastric tube. Physiological variables were also recorded. High-flow nasal cannula delivered at 8 L/min resulted in significant increases in global and anterior end-expiratory lung volume (p < 0.01) and improvements in the physiological variables of respiratory rate, SpO2, and FIO2 when compared with flows of 2 L/min.

CONCLUSION

In infants with bronchiolitis, high-flow nasal cannula oxygen/air delivered at 8 L/min resulted in increases in end-expiratory lung volume and improved respiratory rate, FIO2, and SpO2.

High-flow nasal cannula therapy for respiratory support in children

BACKGROUND

Respiratory support is a central component of the management of critically ill children. It can be delivered invasively via an endotracheal tube or non-invasively via face mask, nasal mask, nasal cannula or oxygen hood/tent. Invasive ventilation can be damaging to the lungs, and the tendency to use non-invasive forms is growing. However, non-invasive delivery is often poorly tolerated by children. High-flow nasal cannula (HFNC) oxygen delivery is a relatively new therapy that shows the potential to reduce the need for intubation and be better tolerated by children than other non-invasive forms of support. HFNC therapy differs from other non-invasive forms of treatment in that it delivers heated, humidified and blended air/oxygen via nasal cannula at rates > 2 L/kg/min. This allows the user to deliver high concentrations of oxygen and to potentially deliver continuous distending pressure; this treatment often is better tolerated by the child.

OBJECTIVES

To determine whether HFNC therapy is more effective than other forms of non-invasive therapy in paediatric patients who require respiratory support.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 4); MEDLINE via PubMed (January 1966 to April 2013); EMBASE (January 1980 to April 2013); CINAHL (1982 to April 2013); and LILACS (1982 to April 2013). Abstracts from conference proceedings, theses and dissertations and bibliographical references to relevant studies were also searched. We applied no restriction on language.

SELECTION CRITERIA

We planned to included randomized controlled trials (RCTs) and quas-randomized trials comparing HFNC therapy with other forms of non-invasive respiratory support for children. Non-invasive support encompassed cot, hood or tent oxygen; low-flow nasal cannulae (flow rates ≤ 2 L/min); and continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BiPAP) delivered via facial or nasal mask/cannula. Treatment failure was defined by the need for additional respiratory support. We excluded children with a diagnosis of bronchiolitis.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed all studies for selection and data extraction. We used standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

Our search yielded 922 records. A total of 109 relevant records were retrieved with reference to our search criteria. After duplicates and irrelevant studies were removed, 69 studies were further scrutinized. Of these, 11 studies involved children. No study matched our inclusion criteria.

AUTHORS' CONCLUSIONS

Based on the results of this review, no evidence is available to allow determination of the safety or effectiveness of HFNC as a form of respiratory support in children.

Nasopharyngeal oxygen with intermittent nose-close and abdomen-compression: a novel resuscitation technique in a piglet model

OBJECTIVE

To evaluate the efficacy of a simple and novel cardiopulmonary resuscitation (CPR) technique, nasopharyngeal oxygen with intermittent nose-close and abdomen-compression (NPO(2) -NC-AC) in an animal model.

DESIGN

Prospective piglet study.

SETTING

In an animal physiology laboratory of a medical university. PIGLETS: Six healthy piglets <14 days old.

INTERVENTIONS

Spontaneous breathing of the anesthetized piglets (n = 6) was medically ceased until severe bradycardia (<20 beat/min). NPO(2) -NC-AC CPR trial was then initiated by delivering NPO(2) at 1.0-1.5 L/kg/min and intermittently performing the NC-AC maneuver: (1) NC for inspiration, occluded nostrils for 1 sec; and (2) AC for expiration, released nostrils, and compressed the abdomen for 1 sec. NC-AC was repeated at a rate of 30/min for 5 min. This CPR trial was repeated three times in each piglet. Cardiopulmonary variables were monitored, recorded, and compared.

MEASUREMENTS AND MAIN RESULTS

A total of 18 CPR trials were performed. All of these acute life-threatening asphyxia events rapidly improved within 1 min of CPR. Cardiopulmonary variables recovered to the baseline levels and oxygenation continually increased. The intratracheal pressure (P(tr) ) values of positive end expiratory pressure and peak inspiratory pressure values were 4.3 ± 0.8 cmH(2) O and 26.2 ± 4.1 cmH(2) O, respectively. Chest wall movement was observed when the P(tr) reached 17.5 ± 3.1 cmH(2) O. All six piglets fully recovered after 63.8 ± 7.2 min of experiment without additional support.

CONCLUSIONS

NPO(2) -NC-AC is a simple and effective CPR technique for severe acute cardiopulmonary asphyxia in piglets. It may be clinically applicable for supportive or rescue use.

CPAP review

Continuous positive airway pressure (CPAP) is widely used in neonatal units both as a primary mode of respiratory support and following extubation from mechanical ventilation. In this review, the evidence for CPAP use particularly in prematurely born infants is considered. Studies comparing methods of CPAP generation have yielded conflicting results, but meta-analysis of randomised trials has demonstrated that delivering CPAP via short nasal prongs is most effective in preventing re-intubation. At present, there is insufficient evidence to establish the safety or efficacy of high flow nasal cannulae for prematurely born infants. Observational studies highlighted that early CPAP use rather than intubation and ventilation was associated with a lower incidence of bronchopulmonary dysplasia (BPD), but this has not been confirmed in three large randomised trials. Meta-analysis of the results of randomised trials has demonstrated that use of CPAP reduces extubation failure, particularly if a CPAP level of 5 cm H2O or more is used. Nasal injury can occur and is related to the length of time CPAP is used; weaning CPAP by pressure rather than by "time-cycling" reduces the weaning time and may reduce BPD. In conclusion, further studies are required to identify the optimum mode of CPAP generation and it is important that prematurely born infants are weaned from CPAP as soon as possible.

High flow nasal cannula for respiratory support in preterm infants

BACKGROUND

High flow nasal cannulae (HFNC) are small, thin, tapered cannulae used to deliver oxygen or blended oxygen and air at flow rates of > 1 L/min. HFNC can be used to provide high concentrations of oxygen and may deliver positive end-expiratory pressure.

OBJECTIVES

To compare the safety and efficacy of HFNC with other forms of non-invasive respiratory support in preterm infants.

SEARCH STRATEGY

The strategy included searches of the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010), MEDLINE, CINAHL, EMBASE and abstracts from conference proceedings.

SELECTION CRITERIA

Randomised or quasi-randomised trials comparing HFNC with other non-invasive forms of respiratory support in preterm infants immediately after birth or following extubation.

DATA COLLECTION AND ANALYSIS

Data were extracted and analysed by the authors. Relative risk, risk difference and number needed to treat were calculated.

MAIN RESULTS

Four studies were identified for inclusion in the review. The studies differed in the interventions compared (nasal continuous positive airway pressure (CPAP), humidified HFNC, non-humidified HFNC), the flow rates provided and the indications for respiratory support. Meta-analysis and subgroup analysis were not possible. When used as primary respiratory support after birth, one trial found similar rates of treatment failure in infants treated with HFNC and nasal CPAP. Following extubation, one trial found that infants treated with HFNC had a significantly higher rate of reintubation than those treated with nasal CPAP. Another trial found similar rates of reintubation for humidified and non-humidified HFNC, and the fourth trial found no difference between two different models of equipment used to deliver humidified HFNC.

AUTHORS' CONCLUSIONS

There is insufficient evidence to establish the safety or effectiveness of HFNC as a form of respiratory support in preterm infants. When used following extubation, HFNC may be associated with a higher rate of reintubation than nasal CPAP. Further adequately powered randomised controlled trials should be undertaken in preterm infants comparing HFNC with nasal CPAP and with other means of respiratory support; or of support following extubation. These trials should measure clinically important outcomes.

Physiologic effects of nasopharyngeal administration of supplemental oxygen at various flow rates in healthy neonatal foals

OBJECTIVE

To evaluate the effects of various flow rates of oxygen administered via 1 or 2 nasal cannulae on the fraction of inspired oxygen concentration (FIO2) and other arterial blood gas variables in healthy neonatal foals.

ANIMALS

9 healthy neonatal (3- to 4-day-old) foals.

PROCEDURES

In each foal, a nasal cannula was introduced into each naris and passed into the nasopharynx to the level of the medial canthus of each eye; oxygen was administered at 4 flow rates through either 1 or both cannulae (8 treatments/foal). Intratracheal FIO2, intratracheal end-tidal partial pressure of carbon dioxide, and arterial blood gas variables were measured before (baseline) and during unilateral and bilateral nasopharyngeal delivery of 50, 100, 150, and 200 mL of oxygen/kg/min.

RESULTS

No adverse reactions were associated with administration of supplemental oxygen except at the highest flow rate, at which the foals became agitated. At individual flow rates, significant and dose-dependent increases in FIO2, PaO2, and oxygen saturation of hemoglobin (SaO2) were detected, compared with baseline values. Comparison of unilateral and bilateral delivery of oxygen at similar cumulative flow rates revealed no differences in evaluated variables.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that administration of supplemental oxygen via nasal cannulae appeared to be a highly effective means of increasing FIO2, PaO2, and SaO2 in neonatal foals. These findings may provide guidance for implementation of oxygen treatment in hypoxemic neonatal foals.

Safe paediatric intensive care. Part 1: Does more medical care lead to improved outcome?

Neonatal and paediatric intensive care has improved the prognosis for seriously sick infants and children. This has happened because of a pragmatic approach focused on stabilisation of vital functions and immense technological advances in diagnostic and therapeutic procedures. However, the belief that more medical care must inevitably lead to improved health is increasingly being questioned. This issue is especially relevant in developing countries where the introduction of highly specialised paediatric intensive care may not lead to an overall fall in child mortality. Even in developed countries, the complexity and availability of therapeutics and invasive procedures may put seriously ill children at additional risk. In both developing and industrialised countries the use of safe and simple procedures for appropriate periods, particular attention to drug prescription patterns and selection of appropriate aims and modes of therapy, including non-invasive methods, may minimise the risks of paediatric intensive care.

Oxygen administration in infants

The main methods of oxygen administration to infants are reviewed. Some methods are more economical and therefore more useful in developing countries. All the methods have potential complications and therefore need to be carefully supervised.