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

Detection of exhaled carbon dioxide following intubation during resuscitation at delivery

OBJECTIVES

End tidal carbon dioxide (ETCO₂) monitoring can facilitate identification of successful intubation. The aims of this study were to determine the time to detect ETCO₂ following intubation during resuscitation of infants born prematurely and whether it differed according to maturity at birth or the Apgar scores (as a measure of the infant's condition after birth).

DESIGN

Analysis of recordings of respiratory function monitoring.

SETTING

Two tertiary perinatal centres.

PATIENTS

Sixty-four infants, with median gestational age of 27 (range 23-34)weeks.

INTERVENTIONS

Respiratory function monitoring during resuscitation in the delivery suite.

MAIN OUTCOME MEASURES

The time following intubation for ETCO₂ levels to be initially detected and to reach 4 mm Hg and 15 mm Hg.

RESULTS

The median time for initial detection of ETCO₂ following intubation was 3.7 (range 0-44) s, which was significantly shorter than the median time for ETCO₂ to reach 4 mm Hg (5.3 (range 0-727) s) and to reach 15 mm Hg (8.1 (range 0-827) s) (both P<0.001). There were significant correlations between the time for ETCO₂ to reach 4 mm Hg (r=-0.44, P>0.001) and 15 mm Hg (r=-0.48, P<0.001) and gestational age but not with the Apgar scores.

CONCLUSIONS

The time for ETCO₂ to be detected following intubation in the delivery suite is variable emphasising the importance of using clinical indicators to assess correct endotracheal tube position in addition to ETCO₂ monitoring. Capnography is likely to detect ETCO₂ faster than colorimetric devices.

WITHDRAWN: Techniques to ascertain correct endotracheal tube placement in neonates

BACKGROUND

The success rate of correct endotracheal tube (ETT) placement for junior medical staff is less than 50% and accidental oesophageal intubation is common. Rapid confirmation of correct tube placement is important because tube malposition is associated with serious adverse outcomes including hypoxaemia, death, pneumothorax and right upper lobe collapse.ETT position can be confirmed using chest radiography, but this is often delayed; hence, a number of rapid point-of-care methods to confirm correct tube placement have been developed. Current neonatal resuscitation guidelines advise that correct ETT placement should be confirmed by the observation of clinical signs and the detection of exhaled carbon dioxide (CO2). Even though these devices are frequently used in the delivery room to assess tube placement, they can display false-negative results. Recently, newer techniques to assess correct tube placement have emerged (e.g. respiratory function monitor), which have been claimed to be superior in the assessment of tube placement.

OBJECTIVES

To assess various techniques for the identification of correct ETT placement after oral or nasal intubation in newborn infants in either the delivery room or neonatal intensive care unit compared with chest radiography.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL,The Cochrane Library 2012, Issue 4), MEDLINE (January 1996 to June 2014), EMBASE (January 1980 to Juen 2014) and CINAHL (January 1982 to June 2014). We searched clinical trials registers and the abstracts of the Society for Pediatric Research and the European Society for Pediatric Research from 2004 to 2014. We did not apply any language restrictions.

SELECTION CRITERIA

We planned to include randomised and quasi-randomised controlled trials and cluster trials that compared chest radiography with clinical signs, respiratory function monitors, exhaled CO2 detectors or ultrasound for the assessment of correct ETT placement either in the delivery room or the neonatal intensive care unit.

DATA COLLECTION AND ANALYSIS

Two review authors independently evaluated the search results against the selection criteria. We did not perform data extraction and 'Risk of bias' assessments because we identified no studies that met our inclusion criteria.

MAIN RESULTS

We did not identify any studies meeting the criteria for inclusion in this review.

AUTHORS' CONCLUSIONS

There is insufficient evidence to determine the most effective technique for the assessment of correct ETT placement either in the delivery room or the neonatal intensive care unit. Randomised clinical trials comparing either of these techniques with chest radiography are warranted.

Assessment of endotracheal tube placement in newborn infants: a randomized controlled trial

OBJECTIVE

International resuscitation guidelines recommend clinical assessment and exhaled CO2 to confirm tube placement immediately after intubation. However, exhaled CO2 devices can display false negative results. In comparison, any respiratory function monitor can be used to measure and display gas flow in and out of an endotracheal tube. However, neither method has been examined in detail. We hypothesized that a flow sensor would improve the assessment of tracheal vs esophageal tube placement in neonates with a higher success rate and a shorter time to tube placement confirmation when compared with the use of a quantitative end-tidal CO2 (ETCO2) detector.

STUDY DESIGN

Between December 2013 and September 2014, preterm and term infants requiring endotracheal intubation were eligible for inclusion and randomly allocated to either ETCO2 ('ETCO2 group') or flow sensor ('flow sensor group'). All infants were analyzed according to their group at randomization (that is, analysis was by intention-to-treat).

RESULT

During the study period, a total of 110 infants (n=55 for each group) were randomized. Successful endotracheal tube placements were correctly identified in 100% of cases by the flow sensor compared with 72% of cases with the ETCO2 detector within 10 inflations (P<0.05). The median (interquartile range) number of inflations needed to identify successful tube placement was significantly lower in the flow sensor group with 2 (1 to 3) inflations vs 8 (6 to 10) inflations with the ETCO2 detector (P<0.001).

CONCLUSION

A flow sensor would improve the assessment of successful endotracheal tube placement with a higher success rate and a shorter time compared with an ETCO2 detector.

Spontaneously Breathing Preterm Infants Change in Tidal Volume to Improve Lung Aeration Immediately after Birth

OBJECTIVE

To examine the temporal course of lung aeration at birth in preterm infants <33 weeks gestation.

STUDY DESIGN

The research team attended deliveries of preterm infants <33 weeks gestation at the Royal Alexandra Hospital. Infants who received only continuous positive airway pressure were eligible for inclusion. A combined carbon dioxide (CO2) and flow-sensor was placed between the mask and the ventilation device. To analyze lung aeration patterns during spontaneous breathing, tidal volume (VT), and exhaled CO2 (ECO2) were recorded for the first 100 breaths.

RESULTS

Thirty preterm infants were included with a total of 1512 breaths with mask leak <30%. Mean (SD) gestational age and birth weight was 30 (1) weeks and 1478 (430) g. Initial VT and ECO2 for the first 30 breaths was 5-6 mL/kg and 15-22 mm Hg, respectively. VT and ECO2 increased over the next 20 breaths to 7-8 mL/kg and 25-32 mm Hg, respectively. For the remaining observation period VT decreased to 4-6 mL/kg and ECO2 continued to increase to 35-37 mm Hg.

CONCLUSIONS

Preterm infants begin taking deeper breaths approximately 30 breaths after initiating spontaneous breathing to inflate their lungs. Concurrent CO2 removal rises as alveoli are recruited. Lung aeration occurs in 2 phases: initially, large volume breaths with poor alveolar aeration followed by smaller breaths with elimination of CO2 as a consequence of adequate aeration.

Techniques to ascertain correct endotracheal tube placement in neonates

BACKGROUND

The success rate of correct endotracheal tube (ETT) placement for junior medical staff is less than 50% and accidental oesophageal intubation is common. Rapid confirmation of correct tube placement is important because tube malposition is associated with serious adverse outcomes including hypoxaemia, death, pneumothorax and right upper lobe collapse.ETT position can be confirmed using chest radiography, but this is often delayed; hence, a number of rapid point-of-care methods to confirm correct tube placement have been developed. Current neonatal resuscitation guidelines advise that correct ETT placement should be confirmed by the observation of clinical signs and the detection of exhaled carbon dioxide (CO2). Even though these devices are frequently used in the delivery room to assess tube placement, they can display false-negative results. Recently, newer techniques to assess correct tube placement have emerged (e.g. respiratory function monitor), which have been claimed to be superior in the assessment of tube placement.

OBJECTIVES

To assess various techniques for the identification of correct ETT placement after oral or nasal intubation in newborn infants in either the delivery room or neonatal intensive care unit compared with chest radiography.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL,The Cochrane Library 2012, Issue 4), MEDLINE (January 1996 to June 2014), EMBASE (January 1980 to Juen 2014) and CINAHL (January 1982 to June 2014). We searched clinical trials registers and the abstracts of the Society for Pediatric Research and the European Society for Pediatric Research from 2004 to 2014. We did not apply any language restrictions.

SELECTION CRITERIA

We planned to include randomised and quasi-randomised controlled trials and cluster trials that compared chest radiography with clinical signs, respiratory function monitors, exhaled CO2 detectors or ultrasound for the assessment of correct ETT placement either in the delivery room or the neonatal intensive care unit.

DATA COLLECTION AND ANALYSIS

Two review authors independently evaluated the search results against the selection criteria. We did not perform data extraction and 'Risk of bias' assessments because we identified no studies that met our inclusion criteria.

MAIN RESULTS

We did not identify any studies meeting the criteria for inclusion in this review.

AUTHORS' CONCLUSIONS

There is insufficient evidence to determine the most effective technique for the assessment of correct ETT placement either in the delivery room or the neonatal intensive care unit. Randomised clinical trials comparing either of these techniques with chest radiography are warranted.

A novel airway device with tactile sensing capabilities for verifying correct endotracheal tube placement

We present a new device for verifying endotracheal tube (ETT) position that uses specialized sensors intended to distinguish anatomical features of the trachea and esophagus. This device has the potential to increase the safety of resuscitation, surgery, and mechanical ventilation and decrease the morbidity, mortality, and health care costs associated with esophageal intubation and unintended extubation by potentially improving the process and maintenance of endotracheal intubation. The device consists of a tactile sensor connected to the airway occlusion cuff of an ETT. It is intended to detect the presence or absence of tracheal rings immediately upon inflation of the airway occlusion cuff. The initial study detailed here verifies that a prototype device can detect contours similar to tracheal rings in a tracheal model.

Noninvasive Monitoring during Interhospital Transport of Newborn Infants

The main indications for interhospital neonatal transports are radiographic studies (e.g., magnet resonance imaging) and surgical interventions. Specialized neonatal transport teams need to be skilled in patient care, communication, and equipment management and extensively trained in resuscitation, stabilization, and transport of critically ill infants. However, there is increasing evidence that clinical assessment of heart rate, color, or chest wall movements is imprecise and can be misleading even in experienced hands. The aim of the paper was to review the current evidence on clinical monitoring equipment during interhospital neonatal transport.

A comparison of different bedside techniques to determine endotracheal tube position in a neonatal piglet model

RATIONALE

Endotracheal tube (ETT) malposition is common and an increasing number of non-invasive techniques to aid rapid identification of tube position are available. Electrical impedance tomography (EIT) is advocated as a tool to monitor ventilation.

OBJECTIVE

This study aimed to compare EIT with five other non-invasive techniques for identifying ETT position in a piglet model.

METHODOLOGY

Six saline lavage surfactant-depleted piglets were studied. Periods of ventilation with ETT placed in the oesophagus or a main bronchus (MB) were compared with an appropriately placed mid-tracheal ETT. Colorimetric end-tidal CO(2) (Pedi-Cap®), SpO(2) and heart rate, tidal volume (${\rm V}_{{\rm T}_{{\rm ao}} } $) using a hot-wire anemometer at the airway opening, tidal volume using respiratory inductive plethysmography (${\rm V}_{{\rm T}_{{\rm RIP}} } $) and regional tidal ventilation within each hemithorax (EIT) were measured.

RESULTS

Oesophageal ventilation: Pedi-Cap® demonstrated absence of color change. ${\rm V}_{{\rm T}_{{\rm ao}} } $, ${\rm V}_{{\rm T}_{{\rm RIP}} } $, and EIT correctly demonstrated no tidal ventilation. SpO(2) decreased from mean (SD) 96 (2)% to 74 (12)% (P < 0.05; Bonferroni post-test), without heart rate change. MB ventilation: SpO(2) , heart rate and Pedi-Cap® were unchanged compared with mid-tracheal position. ${\rm V}_{{\rm T}_{{\rm ao}} } $ and ${\rm V}_{{\rm T}_{{\rm RIP}} } $ decreased from a mean (SD) 10.8 (5.6) ml/kg and 14.6 (6.2) ml/kg to 5.5 (1.9) ml/kg and 6.4 (2.6) ml/kg (both P < 0.05; Bonferroni post-test). EIT identified the side of MB ventilation, with a mean (SD) 95 (3)% reduction in tidal volume in the unventilated lung.

CONCLUSIONS

EIT not only correctly identified oesophageal ventilation but also localized the side of MB ventilation. At present, no one technique is without limitations and clinicians should utilize a combination in addition to clinical judgement.

Confirmation of correct tracheal tube placement in newborn infants

Tracheal intubation remains a common procedure during neonatal intensive care. Rapid confirmation of correct tube placement is important because tube malposition is associated with serious adverse outcomes. The current gold standard test to confirm tube position is a chest radiograph, however this is often delayed until after ventilation has commenced. Hence, point of care methods to confirm correct tube placement have been developed. The aim of this article is to review the available literature on tube placement in newborn infants. We reviewed books, resuscitation manuals and articles from 1830 to the present with the search terms "Infant, Newborn", "Endotracheal intubation", "Resuscitation", "Clinical signs", "Radiography", "Respiratory Function Tests", "Laryngoscopy", "Ultrasonography", and "Bronchoscopy". Various techniques have been studied to help clinicians assess tube placement. However, despite 85 years of clinical practice, the search for higher success rates and quicker intubation continues. Currently, chest radiography remains the gold standard test to confirm tube position. However, rigorous evaluation of new techniques is required to ensure the safety of newborn infants.

Assessment of flow waves and colorimetric CO2 detector for endotracheal tube placement during neonatal resuscitation

AIM

Clinical assessment and end-tidal CO(2) (ETCO(2)) detectors are routinely used to verify endotracheal tube (ETT) placement. However, ETCO(2) detectors may mislead clinicians by failing to identify correct placement under a variety of conditions. A flow sensor measures gas flow in and out of an ETT. We reviewed video recordings of neonatal resuscitations to compare a colorimetric CO(2) detector (Pedi-Cap®) with flow sensor recordings for assessing ETT placement.

METHODS

We reviewed recordings of infants <32 weeks gestation born between February 2007 and January 2010. Airway pressures and gas flow were recorded with a respiratory function monitor. Video recording were used (i) to identify infants who were intubated in the delivery room and (ii) to observe colour change of the ETCO(2) detector. Flow sensor recordings were used to confirm whether the tube was in the trachea or not.

RESULTS

Of the 210 infants recorded, 44 infants were intubated in the delivery room. Data from 77 intubation attempts were analysed. In 35 intubations of 20 infants both a PediCap® and flow sensor were available for analysis. In 21 (60%) intubations, both methods correctly identified successful ETT placement and in 3 (9%) both indicated the ETT was not in the trachea. In the remaining 11 (31%) intubations the PediCap® failed to change colour despite the flow wave indicating correct ETT placement.

CONCLUSION

Colorimetric CO(2) detectors may mislead clinicians intubating very preterm infants in the delivery room. They may fail to change colour in spite of correct tube placement in up to one third of the cases.