Recent discussions
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Colin Morley
Prof Colin Morley MD FRCP 23 High Street, Great Shelford, Cambridge CB22 5EH February 18th 2022 Following the call for public comments below are my thoughts and comments about ILCOR NLS-806-RFM-EtD Respiratory Function Monitoring for Neonatal Resuscitation I was surprised by the recommendation, “There is insufficient evidence to make a recommendation for or against the use of a respiratory function monitor in newborn infants receiving respiratory support at birth (low certainty evidence)”. After an extensive search of the literature, I found 227 papers about monitoring neonatal resuscitations in different ways. It is likely that I have missed some. This may be more than publications and evidence about other individual neonatal resuscitation techniques. I appreciate that the main evidence you look for are randomised controlled trials. However, when these are small, few and possibly biased in various ways it does not seem appropriate to completely ignore other evidence that has accumulated over the years such as animal and observational studies. The basis of medicine is a good understanding of physiology which underpins clinical studies. We should not ignore that. Observational studies may not be strong evidence on their own but when there are many of them all showing similar things then they should be acknowledged and used. A problem with just using randomised trials of monitoring in neonatal resuscitation is that those using a monitor must be trained and experienced in interpreting the data and ensure they look at the monitor and recognise any problems and know how to change the ventilation technique. One of the things that has been commented about using a monitor is that good training is important. People interpreting CTGs, ECGs, chest x-rays etc, and even driving a car, will not be able to do it properly without detailed training. Before a detailed study of resuscitation monitoring, it is vital that we can trust the resuscitators have been trained to use it properly. It has been suggested that watching a monitor distracts the resuscitator from looking at the baby. A problem with the subjective observations and assessments that are recommended in NRP and NLS is they are frequently inaccurate, can’t always help and may be misleading. Important aspects of neonatal resuscitation like mask leak, airway opening, head position and tidal volume can’t be assessed by observation. These can only be determined by monitoring and measuring. Neonatologists will be well trained in the Neonatal Resuscitation Program, Neonatal Life Support program, or similar, which teach resuscitation management largely from observation. This may influence the resuscitators to want to look at the baby rather than a monitor even though the monitor is showing them objective data of what is happening. A problem with RCTs in neonatal resuscitation is that some outcomes e.g. rate of intubation and surfactant treatment may be strongly influenced by training and local protocols and this may affect the results. The RCT in the ILCOR review, by Schmölzer GM, et. “Respiratory function monitor guidance of mask ventilation in the delivery room: a feasibility study”. J Pediatr; 2012 was designed to investigate whether a monitor reduced mask leak and was powered for that. It was associated with significantly less mask leak from 54% to 37%, more adjustments of mask position and airway pressure, and a lower rate of an expiratory tidal volume <8 ml/kg. Using a Resuscitation monitor was not associated with any obvious problems. The RCT by Zeballos Sarrato, “New Strategies of Pulmonary Protection of Preterm Infants in the Delivery Room with the Respiratory Function Monitoring” showed the median expiratory tidal volumes during inflations were greater in the monitor masked group (7 mL/kg) than in the visible group (5.8 mL/kg; p = 0.001). Similarly, the peak inflation pressure was (21.5 vs. 19.7 cmH2O; p < 0.001). No problems with using the monitor were reported. The RCT by van Zantan did not show any differences in outcome between the groups in particular the expired tidal volume was similar in both groups. No problems with using the monitor were reported but in answer to specific post hoc questions the resuscitators thought that more training would be helpful. In the ILCOR document The term “respiratory function monitor” is not described or defined in this document. Inexperienced readers need to know what they measure and why they might be considered useful. Monitors in use, or have been used, are: Respironics NM3, Acutronic Florian, Novametrix Ventcheck, Monivent, ResusRight, NICO CO2 monitor, Newborn resuscitation monitor (Laerdal), Augmented infant resuscitator, Next Step monitor. They do not measure the same parameters in the same way. The recommendation is, “There is insufficient evidence to make a recommendation for or against the use of a respiratory function monitor”. I suggest there is no evidence that using a respiratory function monitor causes problems and that should be clarified. There are suggestions in the ILCOR review, set out below, which are interesting and important, but most are very difficult to achieve because of the difficulties with this sort of research. If ILCOR is to demand this data and outcomes before resuscitation monitoring is recommended, then these criteria should be applied to other parts of the neonatal resuscitation algorithm which are based on little or no research data. “If respiratory function monitoring is implemented, clinical outcome monitoring should continue, for both short term (e.g. face-mask leak, time to HR >100 bpm, TV within desired range and outside the range) and long term clinical outcomes (e.g. BPD, neurodevelopment impairment).” “Research priorities should include human factor assessment, methods exploring opportunities to reduce inequity, and cost-benefit analysis. Standardized operational definitions for outcomes in future studies would permit meta-analysis of results such as mask leak.” “We anticipate implementing RFM into routine clinical practice would require significant training and cost. In addition, there are human factor issues that need to be addressed should RFM be more widespread (see Research priorities section below). Cost of any new treatment or intervention is important but difficult to calculate in the resuscitation of mainly very preterm babies because of so many other confounding factors. It is important to realise that if the use of a Respiratory monitor was to reduce serious handicap the expense of the monitor could easily be cover by saving in the treatment and care costs of such a child. If ILCOR is to demand this data and outcomes before resuscitation monitoring is recommended, then these criteria should be applied to other parts of the neonatal resuscitation algorithm, some of which, are based on little or no research data. After an extensive review of the literature, I found 227 papers about monitoring neonatal resuscitations. I have roughly categorised them: 110 were either about monitoring respiratory parameters or about oxygenation 52 papers were monitoring studies with manikins, 17 were monitoring studies with animals, 26 studies where video recordings were predominantly used, 14 were studies concentrating on expired CO2, 16 were reviews. The titles and abstracts of all these paper can be Obtained from colin@morleys.net. Before you print it you should know there are 100 pages! While considering this review it is important to appreciate the following about resuscitation and respiratory monitoring before it can’t be recommended: 1. Respiratory monitoring is not a new concept. It is an integral part of modern ventilators, both adult and neonatal, measuring and displaying gas flow, inspiratory and expiratory tidal volumes, inflation and expiration times, ventilation pressures and spontaneous breathing. 2. Respiratory monitoring is a fundamental part of the care of mechanically ventilated patients in operating rooms and intensive care units (ICUs) including neonatal intensive care units and so it is already being used. Although surprisingly it is not used at one of the most important and difficult times – resuscitation at birth. 3. Neonatal resuscitation training teaches little about measurement, recording and display of physiological parameters rather it emphasises subjective observations like watching chest rise as an assessment of tidal volume even though this has been shown to be very inaccurate. This has not been the subject of a detailed and stringent review as is being suggested for monitoring. 4. Neonatal resuscitation training also recommends of a set inflating pressures to use even though there is good data that these have little relationship with the delivered tidal volume which is strongly affected by: a baby’s size, gestation, the use of antenatal steroids, volume of lung fluid present, respiratory efforts of the baby, gas leak at the mask or endotracheal tube, laryngeal obstruction of the airway, depressant drugs, equipment used, and experience of the resuscitator. This has not been the subject of a detailed and stringent review as being used for monitoring. There is little recommendation in the training to measure or control tidal volumes. 5. There is increasing data that lung injury in very preterm babies is related to high or low tidal volumes from the positive pressure ventilation used. 6. The MRSOPA mnemonic suggests treatment assessment and changes if treatment is not working such as: Mask adjustment, repositioning the head and neck, suction mouth and nose, opening the mouth, increasing the airway pressure, and using an alternative airway. These are all done on subjective assessments of the effect of the original treatment and effect of any changes. It would be more accurate and appropriate if these were measured. The 227 papers I found highlight the following about monitoring neonatal physiological signals and videos of resuscitations. The sentences below have been taken verbatim from the conclusions in some of the papers. Information about ventilation events and ventilation parameters could potentially be useful during a resuscitation situation by giving immediate feedback to the health care provider. Recording and reviewing vital physiological parameters and video imaging of neonatal resuscitation in the delivery room is a valuable tool for quality assurance, education and research and improve the quality of neonatal resuscitation provided. Recording and reviewing neonatal resuscitation is considered highly beneficial for learning and improving resuscitation skills and is recommended by providers participating in it. During mask ventilation, resuscitators were unable to accurately assess chest wall movement visually from either head or side view. Facemask leak is large during resuscitation of preterm infants using round silicone masks. Tidal volumes delivered during PPV inflations are much higher than those generated during spontaneous breathing by an infant on CPAP. High VT delivery during mask PPV at birth was associated with brain injury. Strategies to limit VT delivery during mask PPV should be used to prevent high VT delivery. Using an RFM was associated with significantly less mask leak, more mask adjustments, and a lower rate of excessive expired tidal volume. A difficult part of neonatal resuscitation is subjectively assessing spontaneous breathing. 1. Providing effective PPV seems easy. However, performing the procedure correctly is extremely challenging. Airway obstruction and face mask large leaks are common. It is estimated that two-thirds of continued neonatal respiratory depression after the time of birth is caused by ineffective or improperly provided PPV. 2. Airway obstruction and face-mask leak are common during the first 2 min of PPV. An RFM enables detection of important airway obstruction and mask leaks. 3. Laryngeal closure impedes non-invasive iPPV at birth and may reduce the effectiveness of non-invasive respiratory support in premature infants immediately after birth. (This would not have been recognised without physiological monitoring) 4. Initial resuscitation via an endotracheal tube, using currently recommended pressures, rarely produced adequate tidal volumes. Resuscitation via an endotracheal tube or a face mask was most effective when the infant's inspiratory effort coincided with an inflation. 5. Substantial tidal volume changes occur before, during and after surfactant administration in the delivery room. Complete airway obstruction is common. Monitoring respiratory function during this procedure may help to assess the delivered tidal volume and airway pressures after surfactant treatment. 6. In 56% of the neonatal resuscitations interruptions in ventilation are frequent with 60% ventilation fraction during the first 30s of PPV. Eliminating disruption for improved quality of PPV delivery should be emphasized when training newborn resuscitation providers. 7. 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. 8. Two-person mask ventilation technique reduces mask leak by approximately 50% compared to the standard one-person mask ventilation method. 9. Video recording identified strengths and weaknesses in the performance of neonatal resuscitation and can facilitate targeted education and quality assurance programmes. 10. Prolonging inflation times during face mask resuscitation of prematurely born infants did not improve ventilation as prolonged inflation did not lead to longer inflation flow times. 11. Expired tidal volumes were significantly greater if the infant inspired during the inflation. 12. Training with a simple RFM significantly reduced the occurrence of excessive PIP and expired tidal volumes 13. EtCO2 monitoring in the DR did not reduce the proportion of admission PCO2 levels outside of the prespecified range in a population of infants supported mostly with noninvasive ventilation. 14. Data have shawn that ECO2 levels can indicate the relative degree of lung aeration after birth and can be used to clinically assess ventilation in the immediate newborn period. 15. Observing tidal volume and ECO2 waveforms adds objectivity to clinical assessments. ECO2 could help assess lung aeration and improve lung recruitment immediately after birth. 16. Infants with congenital diaphragmatic hernia, particularly those who have undergone fetoscopic endoluminal tracheal occlusion have a low lung compliance at birth, and this is further reduced by administration of a neuromuscular blocking agent. 17. Facemask leak is large during resuscitation of preterm infants using round silicone masks. Tidal volumes delivered during PPV inflations are much higher than those generated during spontaneous breathing by an infant on CPAP. 18. Face mask obstruction is common during PPV of preterm infants in the DR. Oropharyngeal airways are associated with significantly higher rates of partial obstruction. 19. Most preterm infants breathe when receiving mask ventilation and this probably contributes to the stabilization of the infants after birth. 20. The 50th percentile for spontaneous tidal volume in preterm infants during mask CPAP ranged from 4.2 to 5.8 mL/kg, with wide individual variation observed in the first minutes after birth. 21. Positive pressure ventilation, guided by VT and EtCO2, potentially optimize lung aeration without excessive tidal volume administered. 22. A sustained inflation of 10 seconds at 25 cmH2O in preterm infants at birth was not effective unless infants breathed. The speculation is that active glottic adduction may be responsible for most ventilation failures. 23. Recordings of physiological parameters and video imaging can improve documentation by providing detailed information. 24. The use of a nasal tube led to large leak, more obstruction, and inadequate tidal volumes compared with face mask. 25. Expiratory volumes were higher, mask leakage lower, and mean airway pressure slightly higher with upright versus standard resuscitator when ventilating a manikin. 26. Directly after birth, ductal shunting is influenced by breathing effort, predominantly with an increase in left-to-right shunt due to inspiration. 27. Tidal volume is highly variable during the anaesthetic care of neonates, and potentially injurious tidal volume is frequently delivered; thus, we suggest close tidal volume monitoring using a dedicated neonatal RFM. 28. Video recording was well-accepted by the staff, useful for objective assessment of performance during resuscitation, and can be used as an educational tool in a low-resource setting. 29. Video recording of neonatal resuscitations, as a standard of care quality assurance activity to enhance caregivers’ learning and create opportunities that improve patient safety is feasible. 30. A video study showed the more corrective ventilation strategies employed the greater the need for intubation. 31. Video recording enables information about adherence to guidelines, technical, behavioural and communication skills within the resuscitation team. 32. ECG may not be reliable and other monitoring, such as cardiac ultrasound and PO, may offer more benefit. 33. Very preterm infants breathe at birth when receiving PPV, but the respiratory effort was significantly lower when compared with infants receiving CPAP only. The reduced breathing effort observed likely justified applying PPV in most infants. 34. This study provides reference ranges of exhaled carbon dioxide, exhaled tidal volumes, and respiratory rate for the first ten minutes after birth in term infants who transition without resuscitation. 35. Two models of self-inflating bags could not provide safe minimum tidal volumes (2.5-5 mL); six models exceeded safety inflation pressure limit >45 cm H2O, representing 6% of their inflations 36. Prenatal caffeine infusion had no significant effect on acute haemodynamic parameters in ventilated preterm lambs during the cardiorespiratory transition. 37. ECG may be inaccurate during resuscitation after asphyxia. 38. Tactile stimulation showed a significant increase in SpO2 in preterm infants. 39. Recording and reviewing neonatal resuscitation is considered highly beneficial for learning and improving resuscitation skills and is recommended by providers participating in it. 40. Wearable eye-tracking technology is feasible to identify gaze fixation on the respiratory monitor display and is well accepted by providers. Neonatal providers look at exhaled tidal volume more than any other parameter. 41. The display of information from an RFM improved the effectiveness of newborn facemask ventilation training. 42. Ventilation correction interventions recommended by the MRSOPA mnemonic improved tidal volume delivery in some cases, but lead to ineffective or excessive tidal volumes in others. Mask leak and obstruction can be induced by MRSOPA manoeuvres. 43. Adding video-debriefing to standard Helping-Babies-Breathe training had an effect on birth attendants' competence attainment and retention over 6 months in Uganda. 44. Parents consider reviewing recordings of neonatal resuscitation as valuable. These positive parental experiences could allay concerns about sharing recordings of neonatal resuscitation with parents. 45. Facemask placement in term and late-preterm infants during neonatal stabilisation are associated with apnoea and this effect is more pronounced after the first compared with subsequent applications. 46. At birth, neonates innately brake expiratory flow to defend FRC gains and redistribute gas to less aerated regions. Yours sincerely, Colin Morley -
Jaqueline Tonelotto
I agree wuth the recomendation that suctioning of clear amniotic fluid from the nose and mouth should not be used as a routine step .Airway positioning and suctioning should be considered if airway obstruction is suspected . -
Jaqueline Tonelotto
I agree. I think the use of ECG is more important than monitoring respiratory function, because we need limited financial resource and we need to practice the good evidences -
Mariza Pereira da silva
Suctioning of clear amniotic fluid is provided when there appears to be excessive fluid pouring out from the mouth and or nose and interfering with satisfactory respiration. -
Manuela Abreu E Lima
It seems that it is not a cost-effective tool (cost outweighs the benefit) -
Manuela Abreu E Lima
It seems to be more important at the time of external cardiac massage -
Emma Crose
n/a -
Shri Alurkar
I don't mind using PEWS as long as it is followed by some specifics of what exactly is wrong with the patient. " Can you see this patient because he is pewsing a 12" should be avoided. -
ANA PAULA CAVANHA
I believe that the use of ECG in the delivery room will add to what is currently being done, but its use must be trained and there are also hospitals that do not have the conditions to have access to ECG in delivery room. -
Jaqueline Tonelotto
I agree. The use of ECG allows more accurace during ressuscitation.