University of Groningen
Response to the authors
de Jager, Pauline; Kneyber, Martin C J
Published in:Annals of Intensive Care DOI:
10.1186/s13613-020-00694-4
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de Jager, P., & Kneyber, M. C. J. (2020). Response to the authors: Feasibility of an alternative, physiologic, individualized open-lung approach to high-frequency oscillatory ventilation in children Response. Annals of Intensive Care, 10(1), [77]. https://doi.org/10.1186/s13613-020-00694-4
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de Jager and Kneyber Ann. Intensive Care (2020) 10:77 https://doi.org/10.1186/s13613-020-00694-4
LETTER TO THE EDITOR RESPONSE
Response to the authors
Pauline de Jager
1and Martin C. J. Kneyber
1,2*© The Author(s) 2020. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://crea-tivecommons.org/licenses/by/4.0/.
We like to thank the authors for their interest in our manuscript and their positive feedback. High-frequency oscillatory ventilation (HFOV) is used in our unit for any type of PARDS when the patient meets specific cri-teria as outlined in our manuscript (in summary, peak inspiratory pressure [PIP] > 28–32 cm H2O, PEEP > 8 cm H2O, FiO2 > 0.60, and oxygenation index [OI] increases on three consecutive 1-h measurements despite increas-ing PEEP) [1]. We understand the author’s perspective that HFOV might be more effective in certain types of PARDS, but we advocate that HFOV should not only be considered in case of refractory hypoxaemia, but also when the bedside team wants to prevent ventilator set-tings becoming toxic. An individualised lung volume optimisation manoeuvre (such as the staircase incre-mental–decremental titration of the continuous distend-ing pressure (CDP) helps in identifydistend-ing patients who have potential for lung recruitability since the response is highly heterogeneous among PARDS [2]. As our data showed, such an individualised manoeuvre can be toler-ated well in terms of haemodynamic effects with a mini-mal risk of barotrauma (in fact, we observed no barotrau-mas following the manoeuvre in our cohort).
The authors raise an important point: what is the “opti-mal” frequency in relation to PARDS severity? Although the concept of the corner frequency is quite clear, it is difficult to detect at the bedside how the “optimal” fre-quency can be identified in heterogenous PARDS [3]. Basically, the lower the lung compliance, the higher the frequency probably should be. For simplicity, when we implemented the HFOV clinical algorithm in our unit, the advice was to start with 12 Hz in all patients,
irrespective of age or PARDS severity and titrate imme-diately after the lung volume optimisation manoeuvre using the PCO2 to give direction (e.g. frequency up or down). Our data confirmed that it was possible to do this in all patients, irrespective of age (Fig. 1).
We agree that in a subgroup of patients in our cohort, especially those with mild-to-moderate PARDS optimi-sation of conventional mechanical ventilation settings might have been attempted. The median OI of 38 as pointed out by the reviewer is the OI after the lung vol-ume optimisation manoeuvre, hence the high CDP we use as part of the open-lung concept confounds the OI. It is true that in general in the paediatric intensive care unit there is a relatively low use of positive end-expira-tory pressure (PEEP) and tolerance of high FiO2 instead. However, the best strategy to optimise CMV in children with severe PARDS remains uncertain [4]. To date, there is no specific PEEP strategy shown to be beneficial nor are there outcome data demonstrating that higher PEEP is better than lower PEEP in PARDS, although there are some suggestions that lower PEEP in PARDS may be associated with increased mortality [5]. We also do not know what the optimal Vt is in (severe) PARDS [6]. Hence, we advocate that HFOV should also be consid-ered if the bedside team wants to prevent ventilator set-tings becoming toxic.
We eagerly await the results of a 2-by-2 factorial ran-domised controlled trial comparing the effects of venti-lation strategy (CMV vs HFOV) with or without prone positioning (http://www.prosp ect-netwo rk.org) on patient outcome [7].
Open Access
*Correspondence: m.c.j.kneyber@umcg.nl
1 Department of Paediatrics, Division of Paediatric Critical Care Medicine,
Beatrix Children’s Hospital, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
Page 2 of 2 de Jager and Kneyber Ann. Intensive Care (2020) 10:77
Acknowledgements
Not applicable.
Authors’ contributions
MK drafted the manuscript. PdJ contributed to the intellectual content of the manuscript. Both authors read and approved the final manuscript.
Funding
None.
Availability of data and materials
Not applicable.
Ethics approval and consent to participate
Not applicable.
Consent for publication
Not applicable.
Competing interests
Dr. Kneyber received unrestricted technical support and lecture fees from Vyaire. Dr. de Jager disclosed that she does not have any potential conflicts of interest.
Author details
1 Department of Paediatrics, Division of Paediatric Critical Care Medicine,
Beatrix Children’s Hospital, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. 2 Critical Care, Anaesthesiology,
Perioperative & Emergency Medicine (CAPE), University of Groningen, Gronin-gen, The Netherlands.
Received: 27 May 2020 Accepted: 4 June 2020
References
1. de Jager P, Kamp T, Dijkstra SK, Burgerhof JGM, Markhorst DG, Curley MAQ, et al. Feasibility of an alternative, physiologic, individualized open-lung approach to high-frequency oscillatory ventilation in children. Ann Intensive Care. 2019;9(1):9.
2. de Jager P, Burgerhof JGM, Koopman AA, Markhorst DG, Kneyber MCJ. Lung volume optimization maneuver responses in pediatric high frequency oscillatory ventilation. Am J Respir Crit Care Med. 2019;199:1034–6.
3. Venegas JG, Fredberg JJ. Understanding the pressure cost of ventilation: why does high-frequency ventilation work? Crit Care Med. 1994;22(9 Suppl):S49–57.
4. Kneyber MCJ, de Luca D, Calderini E, Jarreau PH, Javouhey E, Lopez-Herce J, et al. Recommendations for mechanical ventilation of critically ill chil-dren from the Paediatric Mechanical Ventilation Consensus Conference (PEMVECC). Intensive Care Med. 2017;43(12):1764–80.
5. Khemani RG, Parvathaneni K, Yehya N, Bhalla AK, Thomas NJ, Newth CJL. PEEP lower than the ARDS network protocol is associated with higher pediatric ARDS mortality. Am J Respir Crit Care Med. 2018;198:77–89. 6. de Jager P, Burgerhof JG, van Heerde M, Albers MJ, Markhorst DG,
Kney-ber MC. Tidal volume and mortality in mechanically ventilated children: a systematic review and meta-analysis of observational studies*. Crit Care Med. 2014;42(12):2461–72.
7. Kneyber MCJ, Cheifetz IM, Curley MAQ. High-frequency oscillatory venti-lation for PARDS: awaiting PROSPect. Crit Care. 2020;24(1):118.
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Fig. 1 Level and time course of achieved frequency (F) during the first 72 h of high-frequency oscillatory ventilation (HFOV), stratified by age. “Start” is the first measurement immediately after the recruitment manoeuvre. Data are depicted as median (25–75 interquartile range). * Denotes p < 0.05
