Regulation of oxygen concentration delivered to infants via nasal cannulas

Extended CPAP or low-flow nasal cannula for intermittent hypoxaemia in preterm infants: a 24-hour randomised clinical trial

OBJECTIVE

Optimal timing of continuous positive airway pressure (CPAP) cessation in preterm infants remains undetermined. We hypothesised that CPAP extension compared with weaning to low-flow nasal cannula (NC) reduces intermittent hypoxaemia (IH) and respiratory instability in preterm infants meeting criteria to discontinue CPAP.

DESIGN

Single-centre randomised clinical trial.

SETTING

Level 4 neonatal intensive care unit.

PATIENTS

36 infants <34 weeks' gestation receiving CPAP≤5 cmH2O and fraction of inspired oxygen (FiO2) ≤0.30 and meeting respiratory stability criteria.

INTERVENTIONS

Extended CPAP was compared with weaning to low-flow NC (0.5 L/kg/min with a limit of 1.0 L/min) for 24 hours.

OUTCOMES

The primary outcome was IH (number of episodes with SpO2<85% lasting ≥10 s). Secondary outcomes included: coefficient of variability of SpO2, proportion of time in various SpO2 ranges, episodes (≥10 s) with SpO2<80%, median cerebral and renal oxygenation, median effective FiO2, median transcutaneous carbon dioxide and bradycardia (<100/min for≥10 s).

RESULTS

The median (IQR) episodes of IH per 24-hour period was 20 (6-48) in the CPAP group and 76 (18-101) in the NC group (p=0.03). Infants continued on CPAP had less bradycardia, time with SpO2 <91% and <85%, and lower FiO2 (all p<0.05). There were no statistically significant differences in IH<80%, median transcutaneous carbon dioxide or median cerebral or renal oxygenation.

CONCLUSION

In preterm infants meeting respiratory stability criteria for CPAP cessation, extended CPAP decreased IH, bradycardia and other hypoxaemia measures compared with weaning to low-flow NC during the 24-hour intervention.

TRIAL REGISTRATION NUMBER

NCT04792099.

Environmental or Nasal Cannula Supplemental Oxygen for Preterm Infants: A Randomized Cross-Over Trial

OBJECTIVE

To test the hypothesis that environmental compared with nasal cannula oxygen decreases episodes of intermittent hypoxemia (oxygen saturations <85% for ≥10 seconds) in preterm infants on supplemental oxygen by providing a more stable hypopharyngeal oxygen concentration.

STUDY DESIGN

This was a single center randomized crossover trial with a 1:1 parallel allocation to order of testing. Preterm infants on supplemental oxygen via oxygen environment maintained by a servo-controlled system or nasal cannula with flow rates ≤1.0 L per kg per minute were crossed over every 24 hours for 96 hours. Data were collected electronically to capture real time numeric and waveform data from patient monitors.

RESULTS

Twenty-five infants with gestational age of 27 ± 2 weeks (mean ± SD) and a birth weight of 933 ± 328 g were studied at postnatal day 36 ± 26. The number of episodes of intermittent hypoxemia per 24 hours was 117 ± 77 (median, 98; range, 4-335) with oxygen environment vs 130 ± 63 (median, 136; range, 16-252) with nasal cannula (P = .002). Infants on oxygen environment compared with nasal cannula also had decreased episodes of severe intermittent hypoxemia (P = .005). Infants on oxygen environment compared with nasal cannula had a lower proportion of time with oxygen saturations <85% (.05 ± .03 vs .06 ± .03, P < .001), and a lower coefficient of variation of oxygen saturation (P = .02).

CONCLUSIONS

In preterm infants receiving supplemental oxygen, servo-controlled oxygen environment decreases hypoxemia compared with nasal cannula.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02794662.

In-hospital outcomes of premature infants with severe bronchopulmonary dysplasia

OBJECTIVE

To characterize in-hospital outcomes of premature infants diagnosed with severe bronchopulmonary dysplasia (BPD).

STUDY DESIGN

Retrospective cohort study including premature infants with severe BPD discharged from 348 Pediatrix Medical Group neonatal intensive care units from 1997 to 2015.

RESULTS

There were 10 752 infants with severe BPD, and 549/10 752 (5%) died before discharge. Infants who died were more likely to be male, small for gestational age, have received more medical interventions and more frequently diagnosed with surgical necrotizing enterocolitis, culture-proven sepsis and pulmonary hypertension following 36 weeks of postmenstrual age compared with survivors. Approximately 70% of infants with severe BPD were discharged by 44 weeks of postmenstrual age, and 86% were discharged by 48 weeks of postmenstrual age.

CONCLUSIONS

A majority of infants diagnosed with severe BPD were discharged home by 44 weeks of postmenstrual age. These results may inform discussions with families regarding the expected hospital course of infants diagnosed with severe BPD.

Current concepts of oxygen therapy in neonates

Use of high oxygen concentrations in treating neonatal illness has been challenged in the past few decades. In the face of evidence suggesting adverse outcomes (both clinical and biochemical) with use of high oxygen concentrations, the current guidelines appear to favour use of the lowest possible concentrations of oxygen for the shortest time to treat ill neonates. Current delivery room guidelines recommend using room air when initiating positive pressure ventilation during resuscitation. Targeting appropriate oxygen saturation when delivering supplemental oxygen, both in the delivery room and neonatal intensive care unit (NICU), are now the new emerging standards in neonatal care. Investments in good quality pulse oximeters and oxygen blenders in neonatal care units is now seen as critical to improve newborn survival.

Accuracy of a novel system for oxygen delivery to small children

OBJECTIVE

Oxygen therapy for infants and small children in developing countries is often not available. Entrainment devices may provide an accurate and precise concentration of oxygen when used at the flow rates appropriate for infants and small children.

METHODS

A continuously adjustable entrainment device was tested to determine the concentrations and flows of oxygen delivered by using low inlet flow rates suitable for therapy for infants and small children and 3 distinct oxygen delivery systems that varied in their resistive load.

RESULTS

The use of long and large bore, low resistance tubing (similar to a mask) resulted in the delivery of oxygen concentrations that tracked closely (accurate and precise) to values indicated by the entrainment device. The directly connected system with lower resistance (similar to a hood) produced a similar profile of concentrations and flow rates to the large bore tubing but with even greater accuracy. The use of a long and narrow tubing with higher resistance (similar to a cannula) did not deliver accurate oxygen concentrations. In fact, this high-resistance system failed to work as intended, and instead of entraining air, a large proportion (sometimes >50%) of the oxygen delivered to the entrainment device was ejected through its vents.

CONCLUSIONS

Entrainment devices can deliver accurate oxygen concentrations at low flow rates if used with low resistance delivery systems; however, entrainment devices are not suitable for use with high resistance delivery systems such as a standard nasal cannula.

Improved care and growth outcomes by using hybrid humidified incubators in very preterm infants

OBJECTIVE

To identify changes in temperature, fluid and electrolyte management, growth, and short-term outcome in extremely low birth weight (ELBW) infants nursed in humidified hybrid incubators (HI group) compared with a cohort of patients cared for in nonhumidified conventional incubators (CI group).

METHODS

Body temperature (BT), fluid and electrolyte balance, and growth velocity (GV) were collected retrospectively on 182 ELBW infants. The CI group included ELBW infants cared for with radiant warmers followed by an incubator without humidity. The HI group included ELBW infants cared for in the radiant warmer mode in a Giraffe OmniBed, followed by the incubator mode using high humidity.

RESULTS

The CI group included more multiple births (50.6%) than the HI group (35.8%; P < .05), but there was no difference in demographic characteristics. BT was similar during the first week. The HI group had less fluid intake, urine output, and insensible water loss, less maximum weight loss, and a lower incidence of hypernatremia during the first week than did the CI group (P < .05). The HI group also had a lower frequency of electrolyte sampling and packed red cell transfusion (P < .05), a higher incidence of hyponatremia on postnatal day 1 than the CI group (P < .05), and a higher GV than the CI group (15.2 +/- 5.0 vs 13.5 +/- 4.8 g/kg per day), especially among those with a birth weight of <or=749 g (P < .01). There was no difference in sepsis, necrotizing enterocolitis, intraventricular hemorrhage, and all bronchopulmonary dysplasia (BPD), but there was a decreased incidence of severe BPD (5.1% [HI] vs 16.4% [CI]; P < .05) and duration of assisted ventilation in the HI group compared with the CI group (15.5 +/- 2.1 vs 19.6 +/- 2.4 days, respectively; P = .068).

CONCLUSIONS

Use of a humidified hybrid incubator improved care for ELBW infants by making it possible to decrease fluid intake, improve electrolyte balance, and enhance GV without a disturbance of BT compared with conventional care. By adjusting fluid intake when using these devices, benefits may be enhanced and the risk of BPD and severe BPD may be reduced.

Standardizing nasal cannula oxygen administration in the neonatal intensive care unit

OBJECTIVE

A multicycle, quality improvement method was used to standardize nasal cannula O2 administration and weaning in the NICU.

METHODS

A 2-armed nasal cannula standardized order form (nasal cannula for stable O2 arm and nasal cannula for stable flow arm) was developed after review of the literature, surveying of the practice of NICU physicians and nurse practitioners, and development of consensus among these providers. Outcomes were measured by tracking the distribution of protocol arm chosen, days on O2, weeks on nasal cannula, and disposition of infants who were supported by nasal cannula. Data were collected in an SPSS statistical data set.

RESULTS

Of the 90 infants evaluated, 12 were supported on the stable O2 arm and 53 on the stable flow arm for their entire nasal cannula course. Twenty-five infants switched between arms of support. Patients who were on the stable flow arm of the standard order set for their entire nasal cannula course experienced fewer O2 days but more days on nasal cannula. A subpopulation of infants were supported on nasal cannula flow 0.5 to 1.0 L, with fraction of inspired O2 of 21%. When data from the first 10 weeks of observation were compared with that of the second 10 weeks, the rate of discharge on O2 had decreased from 13 (30%) of 44 to 3 (7%) of 39.

CONCLUSIONS

The multiple steps of literature review, practice surveys, and consensus-building resulted in enthusiastic reception of the nasal cannula standardized order form. The 2-armed nasal cannula protocol forced caregivers to consider which method of support was most beneficial for each infant who was on nasal cannula and allowed a subpopulation of NICU patients to be supported with a lower fraction of inspired O2 than previously used in the NICU.

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.

Oxygen therapy in pediatrics

Oxygen therapy is the most important aspect of supportive care in the management of a critically ill child. Knowledge of the physiology of oxygenation is a key to the proper oxygen therapy. High flow systems are more dependable devices for oxygenation and their use needs to be stressed. Patients on oxygen need close monitoring. Ventilatory support and Continuous Positive Airway Pressure (CPAP) is mandatory in some patients in addition to oxygen therapy for the prevention and treatment of hypoxia.