Effect of time and body position on ventilation in premature infants

[Clinical study of prone positioning in invasive respiratory support for neonatal respiratory distress syndrome]

OBJECTIVES

To assess the effectiveness and safety of prone positioning in the treatment of neonatal respiratory distress syndrome (NRDS) using invasive respiratory support.

METHODS

A prospective study was conducted from June 2020 to September 2023 at Suining County People's Hospital, involving 77 preterm infants with gestational ages less than 35 weeks requiring invasive respiratory support for NRDS. The infants were randomly divided into a supine group (37 infants) and a prone group (40 infants). Infants in the prone group were ventilated in the prone position for 6 hours followed by 2 hours in the supine position, continuing in this cycle until weaning from the ventilator. The effectiveness and safety of the two approaches were compared.

RESULTS

At 6 hours after enrollment, the prone group showed lower arterial blood carbon dioxide levels, inspired oxygen concentration, oxygenation index, rates of tracheal intubation bacterial colonization, and Neonatal Pain, Agitation and Sedation Scale scores compared to the supine group (P<0.05). There were no significant differences between the groups in terms of pH, arterial oxygen pressure, positive end-expiratory pressure, duration of mechanical ventilation, accidental extubation, ventilator-associated pneumonia, air leak syndrome, skin pressure sores, feeding intolerance, and grades II-IV intraventricular hemorrhage (P>0.05).

CONCLUSIONS

Compared to supine positioning, prone ventilation effectively improves oxygenation, increases comfort, and reduces tracheal intubation bacterial colonization in neonates requiring mechanical ventilation for NRDS, without significantly increasing adverse reactions.

Effect of body position on ventilation distribution in healthy newborn infants: an observational study

OBJECTIVES

Newborn infants have unique respiratory physiology compared with older children and adults due to their lungs' structural and functional immaturity and highly compliant chest wall. To date, ventilation distribution has seldom been studied in this age group. This study aims to assess the effect of body position on ventilation distribution in spontaneously breathing healthy neonates.

DESIGN

Prospective observational study.

SETTING

Maternity wards of Oulu University Hospital.

PATIENTS

20 healthy, spontaneously breathing, newborn infants.

INTERVENTIONS

Electrical impedance tomography data were recorded with a 32-electrode belt (Sentec AG, Landquart, Switzerland) in six different body positions in random order. Ventilation distribution was retrospectively assessed 10 minutes after each position change.

MAIN OUTCOME MEASURES

In each position, regional tidal impedance variation (ΔZ) and ventral-to-dorsal and right-to-left centre of ventilation were measured.

RESULTS

The mean global ΔZ was the largest in supine position and it was smaller in prone and lateral positions. Yet, global ΔZ did not differ in supine positions, ventilation distribution was more directed towards the non-dependent lung region in supine tilted position (p<0.001). In prone, a reduction of global ΔZ was observed (p<0.05) corresponding to an amount of 10% of global tidal variation in supine position. In both lateral positions, tidal ventilation was distributed more to the corresponding non-dependent lung region.

CONCLUSIONS

Prone or lateral body positioning in healthy spontaneously breathing newborns leads to a redistribution of ventilation to the non-dependent lung regions and at the same time global tidal volume is reduced as compared with supine.

Imaging of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a multifactorial disease with many associated co-morbidities, responsible for most cases of chronic lung disease in childhood. The use of imaging exams is pivotal for the clinical care of BPD and the identification of candidates for experimental therapies and a closer follow-up. Imaging is also useful to improve communication with the family and objectively evaluate the clinical evolution of the patient's disease. BPD imaging has been classically performed using only chest X-rays, but several modern techniques are currently available, such as lung ultrasound, thoracic tomography, magnetic resonance imaging and electrical impedance tomography. These techniques are more accurate and provide clinically meaningful information. We reviewed the most recent evidence published in the last five years regarding these techniques and analyzed their advantages and disadvantages.

Prolonged Continuous Monitoring of Regional Lung Function in Infants with Respiratory Failure

RATIONALE

Electrical impedance tomography (EIT) allows instantaneous and continuous visualization of regional ventilation and changes in end-expiratory lung volume at the bedside. There is particular interest in using EIT for monitoring in critically ill neonates and young children with respiratory failure. Previous studies have focused only on short-term monitoring in small populations. The feasibility and safety of prolonged monitoring with EIT in neonates and young children has not been demonstrated yet.

OBJECTIVES

To evaluate the feasibility and safety of long-term EIT monitoring in a routine clinical setting and to describe changes in ventilation distribution and homogeneity over time and with positioning in a multi-center cohort of neonates and young children with respiratory failure.

METHODS

At four European University Hospitals, we conducted an observational study (NCT02962505) on 200 patients with post-menstrual ages (PMA) between 25 weeks and 36 months, at risk for or suffering from respiratory failure. Continuous EIT data were obtained using a novel textile 32-electrode interface and recorded at 48 images/s for up to 72 hours. Clinicians were blinded to EIT images during the recording. EIT parameters and the effects of body position on ventilation distribution were analyzed offline.

RESULTS

The average duration of EIT measurements was 53±20 hours. Skin contact impedance was sufficient to allow image reconstruction for valid ventilation analysis during 92[77-98]% (median[interquartile range]) of examination time. EIT examinations were well tolerated, with minor skin irritations (temporary redness or imprint) occurring in 10% of patients and no moderate or severe adverse events. Higher ventilation amplitude was found in the dorsal and right lung areas when compared with the ventral and left regions respectively. Prone positioning resulted in an increase in the ventilation-related EIT signal in the dorsal hemithorax, indicating increased ventilation of the dorsal lung areas. Lateral positioning led to a redistribution of ventilation towards the dependent lung in preterm infants and to the non-dependent lung in patients with PMA above 37 weeks.

CONCLUSIONS

EIT allows continuous long-term monitoring of regional lung function in neonates and young children for up to 72 hours with minimal adverse effects. Our study confirmed the presence of posture-dependent changes in ventilation distribution and their dependency on PMA in a large patient cohort. Clinical trial registered with ClinicalTrials.gov (NCT02962505).

Effect of Position Change From the Bed to a Wheelchair on the Regional Ventilation Distribution Assessed by Electrical Impedance Tomography in Patients With Respiratory Failure

Background: There is limited knowledge about the effect of position change on regional lung ventilation in patients with respiratory failure. This study aimed to examine the physiological alteration of regional lung ventilation during the position change from lying in bed to sitting on a wheelchair.

Methods: In this study, 41 patients with respiratory failure who were weaned from the ventilators were prospectively enrolled. The electrical impedance tomography (EIT) was used to assess the regional lung ventilation distribution at four time points (T_base: baseline, supine position in the bed, T_30min: sitting position in the wheelchair after 30 min, T_60min: sitting position in the wheelchair after 60 min, T_return: the same supine position in the bed after position changing). The EIT-based global inhomogeneity (GI) and center of ventilation (CoV) indices were calculated. The EIT images were equally divided into four ventral-to-dorsal horizontal regions of interest (ROIs 1–4). Depending on the improvement in ventilation distribution in the dependent regions at T_60min (threshold set to 15%), the patients were divided into the dorsal ventilation improved (DVI) and not improved (non-DVI) groups.

Results: When the patients moved from the bed to a wheelchair, there was a significant and continuous increase in ventilation in the dorsal regions (ROI 3 + 4: 45.9 ± 12.1, 48.7 ± 11.6, 49.9 ± 12.6, 48.8 ± 10.6 for T_base, T_30min, T_60min, and T_return, respectively; p = 0.015) and CoV (48.2 ± 10.1, 50.1 ± 9.2, 50.5 ± 9.6, and 49.5 ± 8.6, p = 0.047). In addition, there was a significant decrease in GI at T_60min compared with T_base. The DVI group (n = 18) had significantly higher oxygenation levels than the non-DVI group (n = 23) after position changing. ROI4_Tbase was significantly negatively correlated with the ΔSpO₂ (R = 0.72, p < 0.001). Using a cutoff value of 6.5%, ROI4_Tbase had 79.2% specificity and 58.8% sensitivity in indicating the increase in the dorsal region related to the position change. The corresponding area under the curve (AUC) was 0.806 (95% CI, 0.677–0.936).

Conclusions: Position change may improve the ventilation distribution in the study patients. The EIT can visualize real-time changes of the regional lung ventilation at the bedside to guide the body position change of the patients in the intensive care unit (ICU) and measure the effect of clinical practice.

Trial Registration: Effect of Early Mobilization on Regional Lung Ventilation Assessed by EIT, NCT04081129. Registered 9 June 2019—Retrospectively registered. https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S00096WT&selectaction=Edit&uid=U00020D9&ts=2&cx=v2cwij.

Factors that impact the accuracy with which nurses place preterm infants with respiratory distress syndrome in the prone position

Prone positioning is an important treatment procedure for preterm infants with Respiratory Distress Syndrome (RDS). However, the accuracy with which preterm infants in the Neonatal Intensive Care Unit (NICU) are placed in the prone position is impacted by several factors. The current study aimed to identify these factors. One hundred and twenty-eight nurses were included in this cross-sectional study. Direct observations of the research subjects were used to collect the research data. The participants completed a research questionnaire that included their demographic data and three others to obtain information on their clinical experience, knowledge of positioning, caring behaviors, and efficacy. Independent factors likely to affect preterm infant positioning were evaluated using multivariate logistic regression. The alpha level was set at 5%. Knowledge (p=0.002) and caring behavior (p=0.009) significantly influenced the accuracy with which nurses placed preterm infants with RDS in the prone position. Nursing efficacy, infant’s bodyweight, gestational age, the institution, and DNR decisions did not significantly impact accuracy. NICU nursing staff require interventions to increase their knowledge of the accurate positioning of preterm infants with RDS.

Aerosol drug delivery to spontaneously-breathing preterm neonates: lessons learned

Delivery of medications to preterm neonates receiving non-invasive ventilation (NIV) represents one of the most challenging scenarios for aerosol medicine. This challenge is highlighted by the undersized anatomy and the complex (patho)physiological characteristics of the lungs in such infants. Key physiological restraints include low lung volumes, low compliance, and irregular respiratory rates, which significantly reduce lung deposition. Such factors are inherent to premature birth and thus can be regarded to as the intrinsic factors that affect lung deposition. However, there are a number of extrinsic factors that also impact lung deposition: such factors include the choice of aerosol generator and its configuration within the ventilation circuit, the drug formulation, the aerosol particle size distribution, the choice of NIV type, and the patient interface between the delivery system and the patient. Together, these extrinsic factors provide an opportunity to optimize the lung deposition of therapeutic aerosols and, ultimately, the efficacy of the therapy.

In this review, we first provide a comprehensive characterization of both the intrinsic and extrinsic factors affecting lung deposition in premature infants, followed by a revision of the clinical attempts to deliver therapeutic aerosols to premature neonates during NIV, which are almost exclusively related to the non-invasive delivery of surfactant aerosols. In this review, we provide clues to the interpretation of existing experimental and clinical data on neonatal aerosol delivery and we also describe a frame of measurable variables and available tools, including in vitro and in vivo models, that should be considered when developing a drug for inhalation in this important but under-served patient population.

Oxygenation Instability Assessed by Oxygen Saturation Histograms during Supine vs Prone Position in Very Low Birthweight Infants Receiving Noninvasive Respiratory Support

OBJECTIVE

To evaluate the effect of prone vs supine position on the oxygenation instability among very low birth weight (VLBW) infants receiving noninvasive respiratory support, as assessed by the average oxygen saturation (SpO₂) histograms.

STUDY DESIGN

Sixty-nine histograms from 23 VLBW infants were studied prospectively. Each infant was studied during 3 consecutive 3-hour periods of alternating positions; 12 infants started the study while prone and 11 infants started supine, by random order. Histogram classification system was used to quantify oxygenation stability and time spent in different SpO₂ ranges.

RESULTS

The fraction of inspired oxygen values were similar in both positions. Unstable histograms were more common in supine vs prone position (20/34 [59%] vs 10/35 [29%]; P = .02, respectively). Analyzing oxygenation stability as per position change revealed that a change from prone to supine increased oxygenation instability, and supine to prone decreased instability (P = .02). In the supine vs prone position, percent of time spent in SpO₂ ≤80% and <90% was higher (5.0 ± 4.2 vs 2.4 ± 3.4 [P < .001] and 24.1 ± 13.7 vs 13.2 ± 10.0 [P < .001], respectively), and percent of time in SpO₂ >94% was lower (39.7 ± 26.0 vs 52.4 ± 23.4 [P = .04]).

CONCLUSIONS

Prone positioning decreased oxygenation instability and resulted in higher oxygenation among VLBW premature infants on noninvasive respiratory support. SpO₂ histograms allow easy bedside assessment of oxygenation instability, and quantification of the time spent at different SpO₂ ranges.

Effect of Body Position on Cardiorespiratory Stabilization and Comfort in Preterm Infants on Continuous Positive Airway Pressure

PURPOSE

The purpose of the study is to investigate the effect of four body positions (supine, prone, left lateral, right lateral) on cardiorespiratory stabilization and comfort in preterm infants receiving Nasal Continuous Positive Airway Pressure (NCPAP).

DESIGN AND METHODS

In the study conducted as a randomized crossover design, the sample was composed of 20 preterm infants receiving NCPAP therapy. At each change of position, the baby was allowed to stabilize for 15 min, and heart rate and oxygen saturation values were recorded every 10 min for the next 60 min. The comfort levels of the infants in each position were evaluated at 30th and 60th minutes using the Premature Infant Comfort Scale.

RESULTS

At the end of the study, it was determined that there was no statistically significant difference between heart rate (p = .83), respiratory rate (p = .90) and oxygen saturation (p = .15) of the infants in terms of their positions. When the mean comfort scores of the preterm infants were compared in terms of position, it was found that there was a difference between the positions (p < .01). According to the scale evaluation, the highest comfort level of the infants was in the prone position, which was followed by right lateral, supine and left lateral positions.

PRACTICE IMPLICATIONS

Prone position was the most comfortable for preterm infants. However, comfort levels of preterm infants were also high enough in other positions so that no intervention is needed. In order to ensure comfort and cardiorespiratory stabilization, any of the four body positions can be chosen.

Single-centre prospective observational study on postdelivery room care

OBJECTIVES

As quality of care in the delivery room has major impact on outcome of preterm infants, multiple guidelines have been established in recent years. There is, however, little evidence on how to proceed during postdelivery room care, the time of transfer and admission to the neonatal intensive care unit (NICU). The aim of this study was to identify processes taking place during this period with potential impact on outcome.

STUDY DESIGN

Prospective observational study.

SETTING

Single-centre German tertiary NICU.

PATIENTS

40 inborn preterm infants undergoing postdelivery room care.

MAIN OUTCOME

Prevalence of prolonged duration of postdelivery room care, disconnections from the ventilator and positioning of preterm infants.

RESULTS

Total duration of postdelivery room care and NICU admission procedures were shorter in infants transferred in a transport incubator compared with using a NICU care station from birth. Extremely low birth weight (ELBW) infants spend 8% of the time in prone position in contrast to 39% in non-ELBW. Total duration of disconnection from the ventilator was 50 s and was ten times longer in infants who had nasal CPAP compared with infants intratracheally intubated. Infants with nCPAP had longer duration of disconnection from the ventilator if body weight was >1000 g or if they were transferred in a transport incubator.

CONCLUSIONS

Multiple parameters like birth weight or type of transport affect neonatal care during the postdelivery room period. Prospective studies are needed to identify and optimise parameters within this period that affect long-term outcome.

Physiological Effect of Prone Position in Children with Severe Bronchiolitis: A Randomized Cross-Over Study (BRONCHIO-DV)

OBJECTIVE

To assess the effect of the prone position on physiological measures, including inspiratory effort, metabolic cost of breathing, and neural drive to the diaphragm as compared with the supine position in infants with severe bronchiolitis requiring noninvasive ventilation.

STUDY DESIGN

Fourteen infants, median age 33 days (IQR [first and third quartiles], 25-58) were randomized to receive 7 cmH₂O continuous positive airway pressure for 1 hour in the prone position or in the supine position, which was followed by cross-over to the supine position and the prone position for 1 hour, respectively. Flow, esophageal, airway, gastric, and transdiaphragmatic pressures, as well as electrical activity of the diaphragm were simultaneously recorded. The modified Wood clinical asthma score was also assessed.

RESULTS

Median esophageal pressure-time product per minute was significantly lower in the prone position than in the supine position (227 cmH₂O*s/minute [IQR, 156-282] cmH₂O*s/minute vs 353 cmH₂O*s/minute [IQR, 249-386 cmH₂O*s/minute]; P = .048), as were the modified Wood clinical asthma score (P = .033) and electrical activity of the diaphragm (P = .006). The neuromechanical efficiency of the diaphragm, as assessed by transdiaphramagtic pressure to electrical activity of the diaphragm swing ratio, was significantly higher in the prone position than in the supine position (1.1 cmH₂O/µV [IQR, 0.9-1.3 cmH₂O/µV] vs 0.7 cmH₂O/µV [IQR, 0.6-1.2 cmH₂O/µV], respectively; P = .022).

CONCLUSIONS

This study suggests a benefit of the prone position for infants with severe bronchiolitis requiring noninvasive ventilation by significantly decreasing the inspiratory effort and the metabolic cost of breathing. Further studies are needed to evaluate the potential impact of these physiological findings in a larger population.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT02602678.

Neonatal outcome of small for gestational age preterm infants

Small for gestational age (SGA) preterm neonates (birth weight < -2 SDS) are considered to have increased risk of bronchopulmonary dysplasia (BPD) compared to appropriate for GA (AGA) neonates. It is unclear if SGA infants have increased risk for respiratory distress syndrome (RDS) and mortality. We analyzed data from 515 neonates born <30 weeks GA, 98(19%) were SGA. SGA were compared to AGA by univariate analysis and logistic regression analysis (LRA). Significant variables at univariate analysis were IUGR (67 vs 7%, p = 0.000), chorioamnionitis (1 vs 13%, p = 0.017), pre-eclampsia (62 vs 18%, p = 0.000), surfactant retreatment (47 vs 25%, p = 0.000), BPD (32 vs 20%, p = 0.015), death (30 vs 12%, p = 0.000), SatO2/FiO2 on day 3 (376 vs 433, p = 0.013), and SatO2/FiO2 ratio on day 28 (400 vs 448, p = 0.000). LRA found the following associations: regarding mortality, a decreased Sat/FiO2 ratio on day 3 (OR 1.99, 95% CI 1.26-3.16, p = 0.003); regarding BPD, surfactant retreatment (3.70, 2.11-6.49, p = 0.000), being SGA (2.69, 1.36-5.36, p = 0.005), decreasing GA (1.05, 1.03-1.08, p = 0.000), decreasing SatO2/FiO2 ratio on day 3 (1.25, 1.11-1.40, p = 0.000); and regarding severe RDS, pre-eclampsia (2.68, 1.58-4.55, p = 0.000) and decreasing GA (1.06, 1.04-1.08, p = 0.000).

CONCLUSIONS

In our cohort of preterm infants, being SGA was significantly associated with BPD, but not with increased risk of mortality or RDS due to multiple pathophysiologic mechanisms. What is Known: • Small for gestational age preterm neonates are considered to have increased risk of bronchopulmonary dysplasia (BPD) compared to appropriate for GA neonates. • It is still unclear if SGA infants have increased risk for respiratory distress syndrome (RDS) and mortality. What is New: • In our cohort of 515 preterm infants (19% SGA), being SGA was significantly associated with BPD, but not with increased risk of mortality or RDS. • These results may be explained by the heterogeneity of mechanisms leading to SGA condition and by multiple mechanisms involving lung growth impairment and other factors.