Neonatal Resuscitation With T-Piece Systems: Risk of Inadvertent PEEP Related to Mechanical Properties

Background: Resuscitation of infants using T-piece resuscitators (TPR) allow positive pressure ventilation with positive end-expiratory pressure (PEEP). The adjustable PEEP valve adds resistance to expiration and could contribute to inadvertent PEEP. The study indirectly investigated risk of inadvertent peep by determining expiratory time constants. The aim was to measure system expiratory time constants for a TPR device in a passive mechanical model with infant lung properties.Methods: We used adiabatic bottles to generate four levels of compliance (0.5–3.4 mL/cm H2O). Expiratory time constants were recorded for combinations of fresh gas flow (8, 10, 15 L/min), PEEP (5, 8, 10 cm H2O), airway resistance (50, 200 cm H2O/L/sec and none), endotracheal tube (none, size 2.5, 3.0, 3.5) with a peak inflation pressure of 15 cm H2O above PEEP.Results: Low compliances resulted in time constants below 0.17 s contrasting to higher compliances where the expiratory time constants were 0.25–0.81 s. Time constants increased with increased resistance, lower fresh gas flows, higher set PEEP levels and with an added airway resistance or endotracheal tube.Conclusions: The risk of inadvertent PEEP increases with a shorter time for expiration in combination with a higher compliance or resistance. The TPR resistance can be reduced by increasing the fresh gas flow or reducing PEEP. The expiratory time constants indicate that this may be clinically important. The risk of inadvertent PEEP would be highest in intubated term infants with highly compliant lungs. These results are useful for interpreting clinical events and recordings.

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Assessment of gas flow waves for endotracheal tube placement in an ovine model of neonatal resuscitation

Resuscitation ◽

10.1016/j.resuscitation.2010.02.018 ◽

2010 ◽

Vol 81 (6) ◽

pp. 737-741 ◽

Cited By ~ 13

Author(s):

G.M. Schmölzer ◽

S.B. Hooper ◽

K.J. Crossley ◽

B.J. Allison ◽

C.J. Morley ◽

...

Keyword(s):

Endotracheal Tube ◽

Gas Flow ◽

Neonatal Resuscitation ◽

Tube Placement ◽

Ovine Model ◽

Endotracheal Tube Placement

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Assessment of heart rate changes during positive pressure ventilation in asphyxia induced bradycardia porcine model of neonatal resuscitation

Paediatrics & Child Health ◽

10.1093/pch/pxy054.150 ◽

2018 ◽

Vol 23 (suppl_1) ◽

pp. e59-e60

Author(s):

Liza Espinoza ◽

Po-Yin Cheung ◽

Tze-Fun Lee ◽

Megan O’Reilly ◽

Georg Schmolzer

Keyword(s):

Heart Rate ◽

Animal Models ◽

Endotracheal Tube ◽

Positive Pressure Ventilation ◽

Porcine Model ◽

Neonatal Resuscitation ◽

Positive Pressure ◽

Newborn Piglets ◽

The Mean ◽

Neonatal Resuscitation Program

Abstract BACKGROUND The Neonatal Resuscitation Program (NRP) states that if positive pressure ventilation (PPV) was started because a baby had a low heart rate (HR), the baby’s HR should begin to increase within the first 15sec of PPV. However, this recommendation has not been examined in either an animal models nor in the delivery room. OBJECTIVES To assess changes in HR in piglets with asphyxia induced bradycardia. DESIGN/METHODS Term newborn piglets (n=30) were anesthetized, intubated, instrumented, and exposed to 40min normocapnic hypoxia followed by asphyxia. Asphyxia was achieved by clamping the endotracheal tube until the piglet had bradycardia (defined as HR 25% of baseline); at that time CPR was initiated. As per NRP protocol PPV was immediately started for 30sec followed by chest compression. HR was continuously recorded using an ECG during the whole duration of the experiment. Changes in HR during PPV were assessed and divided into four epochs (0-10sec, 5-15sec, 10-20sec and 20-30sec, respectively) after start of PPV. RESULTS The median (IQR) duration of asphyxia was similar between the groups with 189 (128–291)sec, 126 (70–197)sec, 118 (66–250)sec for 3:1C:V, SI+90 and SI+120 respectively (p=0.37; oneway ANOVA with Bonferroni). At time of start of PPV the mean (SD) HR was 35 (13)/min. An increase in HR >100/min was observed in 6/30 (5%) at 30 seconds of PPV. None achieved changes in HR at the epochs 0-10sec, 5-15sec, or 10-20sec. After 15sec of PPV 13/30 (43%) had a decrease in HR and 11/ 30 (36%) had no change in HR. CONCLUSION Adequate PPV does not increase HR in piglets with asphyxia induced bradycardia. This is contrary to the current NRP, which recommends that after 15 sec of PPV HR should be assessed.

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Evaluation of a Humidified Nasal High-Flow Oxygen System, Using Oxygraphy, Capnography and Measurement of Upper Airway Pressures

Anaesthesia and Intensive Care ◽

10.1177/0310057x1103900620 ◽

2011 ◽

Vol 39 (6) ◽

pp. 1103-1110 ◽

Cited By ~ 121

Author(s):

J. E. Ritchie ◽

A. B. Williams ◽

C. Gerard ◽

H. Hockey

Keyword(s):

Healthy Volunteers ◽

Airway Pressure ◽

Gas Flow ◽

Air Entrainment ◽

High Flow ◽

Positive Pressure ◽

Mean Airway Pressure ◽

Flow Rates ◽

Oxygen Fraction ◽

Airway Pressures

In this study, we evaluated the performance of a humidified nasal high-flow system (Optiflow™, Fisher and Paykel Healthcare) by measuring delivered FiO2 and airway pressures. Oxygraphy, capnography and measurement of airway pressures were performed through a hypopharyngeal catheter in healthy volunteers receiving Optiflow™ humidified nasal high flow therapy at rest and with exercise. The study was conducted in a non-clinical experimental setting. Ten healthy volunteers completed the study after giving informed written consent. Participants received a delivered oxygen fraction of 0.60 with gas flow rates of 10, 20, 30, 40 and 50 l/minute in random order. FiO2, FEO2, FECO2 and airway pressures were measured. Calculation of FiO2 from FEO2 and FECO2 was later performed. Calculated FiO2 approached 0.60 as gas flow rates increased above 30 l/minute during nose breathing at rest. High peak inspiratory flow rates with exercise were associated with increased air entrainment. Hypopharyngeal pressure increased with increasing delivered gas flow rate. At 50 l/minute the system delivered a mean airway pressure of up to 7.1 cmH2O. We believe that the high gas flow rates delivered by this system enable an accurate inspired oxygen fraction to be delivered. The positive mean airway pressure created by the high flow increases the efficacy of this system and may serve as a bridge to formal positive pressure systems.

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Motor responses to positive-pressure breathing in the developing opossum

Journal of Applied Physiology ◽

10.1152/jappl.1985.58.5.1489 ◽

1985 ◽

Vol 58 (5) ◽

pp. 1489-1495 ◽

Cited By ~ 3

Author(s):

J. P. Farber

Keyword(s):

Airway Resistance ◽

Upper Airway ◽

Abdominal Muscle ◽

Positive Pressure ◽

Postnatal Life ◽

Abdominal Muscles ◽

Upper Airways ◽

Motor Responses ◽

Upper Airway Resistance ◽

Upper Airway Muscles

The suckling opossum exhibits an expiration-phased discharge in abdominal muscles during positive-pressure breathing (PPB); the response becomes apparent, however, only after the 3rd-5th wk of postnatal life. The purpose of this study was to determine whether the early lack of activation represented a deficiency of segmental outflow to abdominal muscles or whether comparable effects were observed in cranial outflows to muscles of the upper airways due to immaturity of afferent and/or supraspinal pathways. Anesthetized suckling opossums between 15 and 50 days of age were exposed to PPB; electromyogram (EMG) responses in diaphragm and abdominal muscles were measured, along with EMG of larynx dilator muscles and/or upper airway resistance. In animals older than approximately 30 days of age, the onset of PPB was associated with a prolonged expiration-phased EMG activation of larynx dilator muscles and/or decreased upper airway resistance, along with expiratory recruitment of the abdominal muscle EMG. These effects persisted as long as the load was maintained. Younger animals showed only those responses related to the upper airway; in fact, activation of upper airway muscles during PPB could be associated with suppression of the abdominal motor outflow. After unilateral vagotomy, abdominal and upper airway motor responses to PPB were reduced. The balance between PPB-induced excitatory and inhibitory or disfacilitory influences from the supraspinal level on abdominal motoneurons and/or spinal processing of information from higher centers may shift toward net excitation as the opossum matures.

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Interrupter technique in infancy: Higher airway resistance and lower short-term variability in preterm versus term infants

Pediatric Pulmonology ◽

10.1002/ppul.23771 ◽

2017 ◽

Vol 52 (10) ◽

pp. 1355-1362 ◽

Cited By ~ 3

Author(s):

Jakob Usemann ◽

Désirée Demann ◽

Pinelopi Anagnostopoulou ◽

Insa Korten ◽

Olga Gorlanova ◽

...

Keyword(s):

Airway Resistance ◽

Short Term ◽

Term Infants ◽

Short Term Variability

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Delivery Room Management of Asphyxiated Term and Near-Term Infants

Neonatology ◽

10.1159/000516429 ◽

2021 ◽

pp. 1-13

Author(s):

Marlies Bruckner ◽

Gianluca Lista ◽

Ola D. Saugstad ◽

Georg M. Schmölzer

Keyword(s):

Preterm Infants ◽

Newborn Infants ◽

Neonatal Resuscitation ◽

Birth Asphyxia ◽

Delivery Room ◽

Temperature Management ◽

Term Infants ◽

Term Newborn ◽

Resuscitation Guidelines ◽

Delivery Room Management

Approximately 800,000 newborns die annually due to birth asphyxia. The resuscitation of asphyxiated term newly born infants often occurs unexpected and is challenging for healthcare providers as it demands experience and knowledge in neonatal resuscitation. Current neonatal resuscitation guidelines often focus on resuscitation of extremely and/or very preterm infants; however, the recommendations for asphyxiated term newborn infants differ in some aspects to those for preterm infants (i.e., respiratory support, supplemental oxygen, and temperature management). Since the update of the neonatal resuscitation guidelines in 2015, several studies examining various resuscitation approaches to improve the outcome of asphyxiated infants have been published. In this review, we discuss current recommendations and recent findings and provide an overview of delivery room management of asphyxiated term newborn infants.

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Abstract 170: Temperature Maintenance and Oxygen Use in Newborns at Birth: A Surveillance of Clinical Practice and Compliance with Neonatal Resuscitation Guidelines

Circulation ◽

10.1161/circ.130.suppl_2.170 ◽

2014 ◽

Vol 130 (suppl_2) ◽

Author(s):

Georg M Schmölzer ◽

Roxanne Pinson ◽

Marion Molesky ◽

Heather Chinnery ◽

Karen Foss ◽

...

Keyword(s):

Body Temperature ◽

Knowledge Transfer ◽

Oxygen Saturation ◽

Neonatal Resuscitation ◽

Positive Pressure ◽

Respiratory Therapists ◽

Vaginal Deliveries ◽

Resuscitation Guidelines ◽

The Right ◽

Continuous Positive Pressure

Background: Guidelines of neonatal resuscitation are revised regularly. Gaps in knowledge transfer commonly occur when the guidelines are communicated to the clinical practitioners. Maintaining body temperature and supporting oxygenation are main goals that clinical practitioners aim to achieve in assisting newborns during the feto-neonatal transition at birth. Objectives: In this study, we aim to examine the compliance to guidelines in neonatal resuscitation regarding the temperature maintenance and oxygen use in newborns at birth. Methods: From October to November 2013, a prospective questionnaire surveillance was conducted in all attended deliveries at all four hospitals in Edmonton, Alberta, Canada. All clinical practitioners (registered nurses, physicians and respiratory therapists) were requested to complete the questionnaires immediately after the attended delivery regarding temperature maintenance and oxygenation monitoring. Descriptive statistics were used with mean±SD (range) and % presented. Results: During the 14-days study period, data was obtained in 518 of 712 (73%) attended deliveries of newborns with gestational age 38.6±2.0 (23-42) weeks and birth weight 3324±589 (348-6168) g. Of these deliveries, 58% were normal vaginal deliveries and 29% were cesarean sections. There were 8.8% and 8.4% newborns who required positive pressure ventilation and continuous positive pressure, respectively. Radiant warmer heat was used in 81% (419/518) with 63% (266/419) turned to full power. Room temperature was 21.6±1.6 (17-31)°C. Body temperature at 30-60 min after birth was 36.8±0.5 (32.4-38.1)°C with hypothermia (<36.5°C) in 17%. Percutaneous oxygen saturation was measured in 15% newborns and 96% had sensors placed at the right wrist. At the initiation of resuscitation, 21% oxygen was used in 76% and the oxygen concentration was adjusted according to an oxygen saturation chart in 17%. In 70% of the cases, clinical practitioners commented that this chart was not helpful. Conclusions: Gaps in knowledge transfer contribute to non-compliance in the guidelines of neonatal resuscitation for temperature maintenance and oxygen use. Caution is needed to avoid hypothermia and hyperoxia in at-risk populations such as prematurity.

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Manual ventilation devices in neonatal resuscitation: Tidal volume and positive pressure-provision

Resuscitation ◽

10.1016/j.resuscitation.2009.10.008 ◽

2010 ◽

Vol 81 (2) ◽

pp. 202-205 ◽

Cited By ~ 38

Author(s):

Charles C. Roehr ◽

Marcus Kelm ◽

Hendrik S. Fischer ◽

Christoph Bührer ◽

Gerd Schmalisch ◽

...

Keyword(s):

Tidal Volume ◽

Neonatal Resuscitation ◽

Positive Pressure ◽

Manual Ventilation

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Frequency response of the chest: modeling and parameter estimation

Journal of Applied Physiology ◽

10.1152/jappl.1975.39.4.523 ◽

1975 ◽

Vol 39 (4) ◽

pp. 523-534 ◽

Cited By ~ 47

Author(s):

R. Peslin ◽

J. Papon ◽

C. Duviver ◽

J. Richalet

Keyword(s):

Frequency Response ◽

Gas Flow ◽

Airway Resistance ◽

Mechanistic Model ◽

Normal Subjects ◽

Order Equation ◽

Mean Values ◽

Tissue Compliance ◽

Linear Differential ◽

Gas Compressibility

The frequency response of the respiratory system was studied in the range from 3 to 70 Hz in 15 normal subjects by applying sinusoidal pressure variations around the chest and measuring gas flow at the mouth. The observed input-output relationships were systematically compared to those predicted on the basis of linear differential equations of increasing order. From 3 to 20 Hz the behavior of the system was best described by a 3rd-order equation, and from 3 to 50 Hz by a 4th-order one. A mechanistic model of the 4th order, featuring tissue compliance (Ct), resistance (Rt) and inertance (It), alveolar gas compressibility (Cg) and airway resistance (Raw), and inertance (Iaw) was developed. Using that model, the following mean values were found: Ct = 2.08–10(-2)1-hPa-1 (1 hPa congruent to 1 cm of water); Rt = 1.10-hPa-1(-1)-s; It = 0.21–10(-2)hPa-1(-1)-s2; Raw = 1.35-hPa-1(-1)-s; Iaw = 2.55–10(-2)hPa-1(-1)-s2. Additional experiments devised to validate the model were reasonably successful, suggesting that the physical meaning attributed to the coefficients was correct. The validity of the assumptions and the physiological meaning of the coefficients are discussed.

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Novel Neonatal Simulator Provides High-Fidelity Ventilation Training Comparable to Real-Life Newborn Ventilation

Children ◽

10.3390/children8100940 ◽

2021 ◽

Vol 8 (10) ◽

pp. 940

Author(s):

Joanna Haynes ◽

Peder Bjorland ◽

Øystein Gomo ◽

Anastasia Ushakova ◽

Siren Rettedal ◽

...

Keyword(s):

Skill Acquisition ◽

Low Cost ◽

Negative Relationship ◽

Real Life ◽

Neonatal Resuscitation ◽

Healthcare Personnel ◽

Positive Pressure ◽

High Fidelity ◽

High Resource ◽

Clinical Conditions

Face mask ventilation of apnoeic neonates is an essential skill. However, many non-paediatric healthcare personnel (HCP) in high-resource childbirth facilities receive little hands-on real-life practice. Simulation training aims to bridge this gap by enabling skill acquisition and maintenance. Success may rely on how closely a simulator mimics the clinical conditions faced by HCPs during neonatal resuscitation. Using a novel, low-cost, high-fidelity simulator designed to train newborn ventilation skills, we compared objective measures of ventilation derived from the new manikin and from real newborns, both ventilated by the same group of experienced paediatricians. Simulated and clinical ventilation sequences were paired according to similar duration of ventilation required to achieve success. We found consistencies between manikin and neonatal positive pressure ventilation (PPV) in generated peak inflating pressure (PIP), mask leak and comparable expired tidal volume (eVT), but positive end-expiratory pressure (PEEP) was lower in manikin ventilation. Correlations between PIP, eVT and leak followed a consistent pattern for manikin and neonatal PPV, with a negative relationship between eVT and leak being the only significant correlation. Airway obstruction occurred with the same frequency in the manikin and newborns. These findings support the fidelity of the manikin in simulating clinical conditions encountered during real newborn ventilation. Two limitations of the simulator provide focus for further improvements.

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