Picetti et al. Critical Care (2020) 24:158 https://doi.org/10.1186/s13054-020-02875-w RESEARCH Open Access VENTILatOry strategies in patients with severe traumatic brain injury: the VENTILO Survey of the European Society of Intensive Care Medicine (ESICM) Edoardo Picetti1*, Paolo Pelosi2,3, Fabio Silvio Taccone4, Giuseppe Citerio5, Jordi Mancebo6, Chiara Robba2 and on the behalf of the ESICM NIC/ARF sections Abstract Background: Severe traumatic brain injury (TBI) patients often develop acute respiratory failure. Optimal ventilator strategies in this setting are not well established. We performed an international survey to investigate the practice in the ventilatory management of TBI patients with and without respiratory failure. Methods: An electronic questionnaire, including 38 items and 3 different clinical scenarios [arterial partial pressure of oxygen (PaO2)/inspired fraction of oxygen (FiO2) > 300 (scenario 1), 150–300 (scenario 2), < 150 (scenario 3)], was available on the European Society of Intensive Care Medicine (ESICM) website between November 2018 and March 2019. The survey was endorsed by ESICM. Results: There were 687 respondents [472 (69%) from Europe], mainly intensivists [328 (48%)] and anesthesiologists [206 (30%)]. A standard protocol for mechanical ventilation in TBI patients was utilized by 277 (40%) respondents and a specific weaning protocol by 198 (30%). The most common tidal volume (TV) applied was 6–8 ml/kg of predicted body weight (PBW) in scenarios 1–2 (72% PaO2/FIO2 > 300 and 61% PaO2/FiO2 150–300) and 4–6 ml/kg/ PBW in scenario 3 (53% PaO2/FiO2 < 150). The most common level of highest positive end-expiratory pressure (PEEP) used was 15 cmH2O in patients with a PaO2/FiO2 ≤ 300 without intracranial hypertension (41% if PaO2/FiO2 150–300 and 50% if PaO2/FiO2 < 150) and 10 cmH2O in patients with intracranial hypertension (32% if PaO2/FiO2 150–300 and 33% if PaO2/FiO2 < 150). Regardless of the presence of intracranial hypertension, the most common carbon dioxide target remained 36–40 mmHg whereas the most common PaO2 target was 81–100 mmHg in all the 3 scenarios. The most frequent rescue strategies utilized in case of refractory respiratory failure despite conventional ventilator settings were neuromuscular blocking agents [406 (88%)], recruitment manoeuvres [319 (69%)] and prone position [292 (63%)]. Conclusions: Ventilatory management, targets and practice of adult severe TBI patients with and without respiratory failure are widely different among centres. These findings may be helpful to define future investigations in this topic. Keywords: Traumatic brain injury, Mechanical ventilation, Respiratory failure * Correspondence: edoardopicetti@hotmail.com 1 Department of Anesthesia and Intensive Care, Parma University Hospital, Via Gramsci 14, 43100 Parma, Italy Full list of author information is available at the end of the article © The Author(s). 2020 Open Access 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://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Picetti et al. Critical Care (2020) 24:158 Page 2 of 9 Background 11, 12 and 14) and (c) respiratory management strat- Traumatic brain injury (TBI) is a worldwide health prob- egies (questions 13 and 15 to 38). The target audi- lem with elevated rate of mortality and disability [1]. ence was ESICM members who had agreed to Brain-injured patients with altered consciousness fre- participate in ESICM surveys at the time of their quently require intubation and invasive mechanical ven- membership registration and who treat patients with tilation to protect the airways from aspiration and to TBI in their clinical practice. The investigators invited prevent harmful secondary insults, such as hypoxemia the target participants to involve more respondents [generally defined as an arterial partial pressure of oxy- locally. Participants did not receive compensation for gen (PaO2) < 60 mmHg] and hypercapnia [generally de- their participation in the survey, which was distrib- fined as an arterial partial pressure of carbon dioxide uted via the ESICM office, thus protecting data confi- (PaCO2) > 45 mmHg] [2]. TBI patients may develop se- dentiality and anonymity. The survey was registered vere respiratory failure and acute respiratory distress within the ESICM Survey portfolio and no ethical ap- syndrome (ARDS) during intensive care unit (ICU) stay proval was required. The questionnaire was not spe- [3, 4]. Lung-protective ventilation strategies, with low cifically tested in a pilot cohort of potential tidal volumes (TVs) and moderate-to-high positive end- respondents but underwent a peer-review process expiratory pressure (PEEP), are associated with improved within the ESICM Research Committee. outcomes in ARDS and non-ARDS patients [5, 6] and are characterized by “low ranges” oxygenation targets Data analyses and statistical methods and permissive hypercapnia [7, 8]. This approach, con- Data from the questionnaire were exported as a comma- sidering its potential adverse cerebrovascular effects, is separated value report from the Surveymonkey® software difficult to apply in TBI patients, regardless of the pres- package and subsequently stored as an Excel file (Micro- ence of intracranial hypertension [2, 9, 10]. Traditionally, soft Corp, Redmond, WA). Descriptive statistics were in TBI patients, low PEEP and high TVs are generally computed for all study variables. The results are pre- applied for tight CO2 control [5]; however, recent evi- sented as numbers and percentage. Two main subdivi- dence suggests that, even in TBI patients, the use of high sions were considered in the population: one based on TVs is associated with the development of acute lung in- geographic area (Europe vs. Others), one based on ICU jury [9, 11]. As such, brain-injured patients have been characteristics [specialized neuro-ICU (NICU) vs. non- excluded from the major trials exploring the effect of specialized NICU]. Results for the population as a whole lung-protective ventilation strategies in ARDS [12, 13], and for the sub-group subdivision are reported. Differ- and consequently optimal ventilatory strategies have not ences between groups (e.g. specialized NICU vs. non- been established yet in this setting [14, 15]. We therefore specialized NICU, Europe vs. Others) were assessed performed an international survey with the aim to inves- using a chi-squared test for binary variables in 2 × 2 or tigate the practice in the respiratory management of TBI r × c contingency tables. Cells with fewer than 5 cases patients, with and without respiratory failure. were grouped with other cells taking care that the new group was clinically appropriate. For the questions Methods where more than one test was necessary (for example This international survey was endorsed by the European So- questions concerning rescue strategies), a Bonferroni ciety of Intensive Care Medicine (ESICM) and promoted by correction for multiple comparisons was adopted. Stata the Neuro-intensive Care (NIC) and the Acute Respiratory software release 13.0 was used for the statistical analysis Failure (ARF) sections. An electronic questionnaire, includ- (StataCorp, 2013, Stata Statistical Software, Release 13; ing 38 items and 3 different clinical scenarios [PaO2 / in- StataCorp LP, College Station, TX). P < 0.05 was consid- spired fraction of oxygen (FiO2) (PaO2/FiO2) > 300, 150– ered as statistically significant. 300, < 150], was available on the ESICM website between November 2018 and March 2019 (Appendix 1 in the Results Additional file 1). The survey was developed by two investi- The total number of respondents was 687 from 676 cen- gators (E.P. and C.R.) following a non-systematic review of tres around the world [the number of respondents in re- the literature on respiratory management in TBI patients. lation to completed items is shown Table S1 in the The questionnaire was created considering some issues Additional file 1). Most of the respondents (n = 472 around this topic, such as low levels of evidence, lack of good [69%]) were from Europe. Italy was the country with the quality studies and controversial results from observational highest number of respondents (n = 86), followed by trials. The survey was designed to identify (a) characteristics Sudan (n = 60), the USA (n = 47) and Brazil (n = 43) of the participants demographics, type of hospital/specialty (Fig. 1). The majority of respondents were intensivists and available neuromonitoring tools (questions 1 to 10), (b) (n = 328 [48%]) and anesthesiologists (n = 206 [30%]) protocols for mechanical ventilation and weaning (questions working in mixed general and NICUs (n = 278 [41%]). Picetti et al. Critical Care (2020) 24:158 Page 3 of 9 Fig. 1 Number of respondents per country. Only countries with a number of responses > 20 have been included. Abbreviations: USA = United States of America. The number of respondents is shown in brackets Baseline characteristics of the survey participants are The most frequent rescue strategies utilized in case of shown in Table 1. refractory respiratory failure, despite the application of a A standard protocol for mechanical ventilation in TBI lung-protective ventilation strategy, were neuromuscular patients was utilized by 277 (40%) respondents and a blocking agents (NMBAs) [406 (88%)], followed by re- specific weaning protocol by 198 (30%). Automated ven- cruitment manoeuvres [319 (69%)] and prone position tilation modes were utilized by 331 (50%) participants. A [292 (63%)] (Table 3). driving pressure < 15 cmH2O and a plateau pressure < Data regarding comparisons between European versus 30 cmH2O were utilized by most respondents [respect- non-European respondents and non-specialized versus ively 436 (68%) and 616 (95%)]. specialized NICUs are reported in Table S2 in the Ventilator settings and respiratory targets utilized in Additional file 1. European respondents, when compared the three clinical scenarios with different respiratory fail- to non-European, had (1) less frequently standardized ure severity are reported in Table 2. The most common protocols for mechanical ventilation and weaning, (2) TV applied was 6–8 ml/kg/predicted body weight (PBW) higher PaCO2 targets, (3) a higher utilization of neuro- in case of PaO2/FiO2 ≥ 150 (72% for PaO2/FiO2 > 300 monitoring to set PaO2 targets and (4) more frequent and 61% for PaO2/FiO2 150–300) and 4–6 ml/kg/PBW use of NMBAs as rescue strategy for refractory respira- in case of PaO2/FiO2 < 150 (53%). In patients without tory failure. intracranial hypertension, the most utilized highest PEEP Respondents working in specialized NICUs, compared and PaCO2 targets in all 3 clinical scenarios were to those from non-specialized NICUs, had (1) a less fre- 15 cmH2O (30% for PaO2/FiO2 > 300, 41% for PaO2/ quent use of plateau pressure target < 30 cmH2O and (2) FiO2 150–300 and 50% for PaO2/FiO2 < 150) and 36–40 higher PaO2 targets. mmHg (51% for PaO2/FiO2 > 300, 47% for PaO2/FiO2 Data regarding available bedside neuromonitoring be- 150–300 and 37% for PaO2/FiO2 < 150) respectively. In tween non-specialized versus specialized NICUs are re- patients with intracranial hypertension, the most utilized ported in Table S3 in the Additional file 1. Except for highest PEEP was 5 cmH2O in scenario 1 (27%) and near-infrared spectroscopy (NIRS), specialized NICUs, 10 cmH2O in scenarios 2–3 (32% for PaO2/FiO2 150– compared to non-specialized NICUs, had more available 300 and 33% for PaO2/FiO2 < 150) whereas the PaCO2 bedside neuromonitoring tools. targets were 36–40 mmHg in all 3 scenarios (43% for PaO2/FiO2 > 300, 49% for PaO2/FiO2 150–300 and 47% Discussion for PaO2/FiO2 < 150). The most common PaO2 target This international survey provides important informa- was 81–100 mmHg in all the 3 groups (57% for PaO2/ tion regarding the respiratory management of TBI pa- FiO2 > 300, 53% for PaO2/FiO2 150–300 and 45% for tients admitted to ICU. The main results of our survey PaO2/FiO2 < 150). can be summarized as follows: (1) few respondents uti- The most common ventilator settings and respiratory lized specific protocols for mechanical ventilation and targets in the 3 clinical scenarios are presented in Fig. 2. weaning in TBI, (2) low TVs with a PaCO2 target of 36– Picetti et al. Critical Care (2020) 24:158 Page 4 of 9 Table 1 Baseline characteristics of the overall population 40 mmHg are frequently utilized, (3) lower levels of Respondents (n = 687) PEEP are employed in case with intracranial hyperten- Gender sion, (4) NMBAs are the most common rescue strategy Male 452 (66%) in cases of refractory respiratory failure and finally (5) a great variability in practices exists. Female 235 (34%) To our knowledge, this is the largest survey published Age (years) so far regarding ventilator strategies in head injured pa- < 35 115 (17%) tients. Respondents are coming from different countries 35–45 282 (41%) around the world, and therefore, our results are repre- 45–65 249 (36%) sentative of the worldwide current clinical practice in > 65 41 (6%) this field. Specialty Ventilator settings and respiratory targets in TBI Intensive care medicine 328 (48%) Lung-protective ventilation strategies have shown to Anesthesiology 206 (30%) have a beneficial impact on outcome in patients with Neurocritical care 61 (9%) and without ARDS [15]. In particular, low TVs are a Internal medicine 35 (5%) fundamental component of lung-protective ventilation Others 57(8%) and their utilization is associated with a reduced mortal- ity in ARDS patients [5, 6]. Although low TVs can po- Post-specialization experience in critical care (years) tentially cause hypercapnia and consequent intracranial 1–5 180 (26%) cerebral vessel vasodilation, the use of high TVs in TBI 6–10 149 (22%) patients (> 9 ml/kg/PBW), with normal lung at ICU ad- > 10 358 (52%) mission, is associated with the development of ARDS Type of ICU [11]. Prospective studies regarding low TVs are lacking Mixed general and neuroICU 278 (41%) in TBI and the optimal TV value still need to be estab- lished in this setting. Surprisingly, the majority of our re- General ICU 271 (39%) spondents declared that they utilize low TVs, even in Specialized neuroICU 130 (19%) specialized NICUs, thus suggesting that the concept of Others 8 (1%) lung-protective ventilation is gaining interest even in this ICU beds group of patients. <5 111 (16%) The application of PEEP, as well as low TVs, is an im- 6–10 196 (29%) portant component of lung-protective ventilation [7]. PEEP reduces atelectasis and improves PaO2 and lung 11–15 133 (19%) compliance [7]. Traditionally, low PEEP levels (≤ 5 > 15 247 (36%) mmHg) have been utilized in acute brain injury patients Affiliation admitted to ICU [5], because of the potential risks on University 501 (73%) cerebral circulation and intracranial pressure (ICP); in Non-university 186 (27%) particular, the effect of PEEP on ICP seems to be related Available bedside neuromonitoring to both hemodynamic factors and respiratory system compliance [9, 10]. Elevated PEEP levels may reduce sys- ICP 546 (80%) temic venous return, mean arterial pressure and PbtO2 149 (22%) consequently cerebral perfusion pressure (CPP) with NIRS 215 (31%) detrimental consequences on cerebral blood flow (CBF), TCD 442 (64%) mainly in cases of altered cerebral autoregulation [16]. Cerebral microdialysis 50 (7%) On the other hand, respiratory system compliance influ- Intermittent EEG 522 (76%) ences the effect of PEEP on ICP and brain circulation [17–19]: in patients with low compliance, a PEEP in- Continuous EEG 262 (38%) crease (up to 10–12 cmH2O) is not associated with ICP Pupillometer 85 (12%) increase; in contrast, in patients with normal compli- SjVO2 209 (30%) ance, PEEP induces lung overdistension, reduction in Abbreviations: ICU intensive care unit, ICP intracranial pressure, PbtO2 brain cerebral venous return and ICP increases. We found that tissue oxygen tension, NIRS near infrared spectroscopy, TCD transcranial Doppler, EEG electroencephalography, SjVO2 jugular venous oxygen saturation most of our respondents utilize lower PEEP levels in case of intracranial hypertension, thus suggesting that there is still concern regarding the cerebrovascular Table 2 Ventilator settings and respiratory targets utilized in the three clinical scenarios PaO2/FiO2 TV (ml/kg PBW) Highest PEEP Highest PEEP PaCO2 PaCO2 PaO2 (mmHg) SpO2 (%) no-IH IH no-IH IH (cmH2O) (cmH2O) (mmHg) (mmHg) Picetti et al. Critical Care 1) > 300 6–8 15 5 36–40 36–40 81–100 > 95 [433(72%)] [182(30%)] [163(27%)] [308(51%)] [260(43%)] [345(57%)] [311(52%)] 4–6 10 10 41–45 30–35 55–80 92–94 [136(23%)] [158(26%)] [155(26%)] [105(18%)] [249(41%)] [101(17%)] [257(43%)] 8–10 8 8 any PaCO2* 41–45 101–120 88–91 [21(3%)] [94(15%)] [135(23%)] [93(16%)] [42(8%)] [93(15%)] [33(5%)] other 5 15 30–35 46–55 nmt** (2020) 24:158 [11(2%)] [69(13%)] [52(8%)] [54(9%)] [8(1%)] [44(7%)] other other 46–55 any PaCO2* > 120 [98(16%)] [96(16%)] [16(2%)] [7(1%)] [18(4%)] other other [25(4%)] [35(6%)] 2) 150–300 6–8 15 [218(41%)] 10 36–40 36–40 81–100 92–94 [331(61%)] 10 [136(25%)] [171(32%)] [250(47%)] [262(49%)] [283(53%)] [258(48%)] 4–6 8 [71(13%)] 8 41–45 30–35 55–80 > 95 [192(36)] 5 [23(5%)] [131(24%)] [110(21%)] [176[33%)] [115(21%)] [228(43%)] 8–10 other [88(16%)] 5 any PaCO2* 41–45 101–120 88–91 [3(1%)] [103(19%)] [91(19%)] [54(9%)] [84(16%)] [50(9%)] other 15 46–55 any PaCO2* nmt** [10(2%)] [54(11%)] [35(6%)] [10(2%)] [35(6%)] other 30–35 46–55 > 120 [77(14%)] [34(6%)] [4(1%)] [19(4%)] other other [20(4%)] [30(6%)] 3) < 150 4–6 15 [239(50%)] 10 36–40 36–40 81–100 92–94 [252(53%)] 10 [95(20%)] [158(33%)] [175(37%)] [224(47%)] [218(45%)] [227(47%)] 6–8 8 [37(7%)] 8 41–45 30–35 55–80 > 95 [203(42%)] 5 [14(3%)] [94(20%)] [118(25%)] [129[26%)] [151(32%)] [148(31%)] 8–10 other [96(20%)] 15 any PaCO2* 41–45 101–120 88–91 [9(2%)] [91(19%)] [87(16%)] [75(16%)] [61(13%)] [106(22%)] other 5 46–55 any PaCO2* nmt** [16(3%)] [55(11%)] [48(10%)] [15(3%)] [36(7%)] other 30–35 46–55 > 120 [83(17%)] [29(7%)] [9(2%)] [14(3%)] other other [19(5%)] [29(6%)] *If arterial pH is in range **Adjusted to Abbreviations: TV tidal volume, PEEP positive end-expiratory pressure, PaCO2 partial pressure of arterial carbon dioxide, PaO2 partial pressure of arterial oxygen, SpO2 arterial blood oxygen saturation, IH intracranial hypertension, PBW predicted body weight, nmt neuromonitoring Page 5 of 9 Picetti et al. Critical Care (2020) 24:158 Page 6 of 9 Fig. 2 The commonest ventilator settings and respiratory targets in the three clinical scenarios. Abbreviations: TV = tidal volume, PBW = predicted body weight, PEEP = positive end-expiratory pressure, IH = intracranial hypertension, PaCO2 = arterial partial pressure of carbon dioxide, PaO2 = arterial partial pressure of oxygen, SpO2 = arterial blood oxygen saturation, FiO2 = inspired oxygen fraction effects of PEEP on ICP. However, surprisingly, our re- related to the potential ischemic side effects of hypocap- sults show that physicians are keen to use quite high nia on the injured brain [21]. Currently, hyperventilation PEEPs (up to 15 in patients with PaO2/FiO2 > 300) in pa- is suggested only in case of emergency with life- tients without intracranial hypertension, which is in con- threatening risk of cerebral herniation [22]. However, re- trast with growing evidence challenging the utility of cent findings suggested that mild, short-term hyperventi- “open lung approach” [20]. Probably, the availability of lation is able to reduce ICP, without a clinically adequate neuro and cardiorespiratory monitoring tools significant reduction of cerebral oxygenation and metab- could be useful in setting the right level of PEEP, but olism [23]. In fact, most responders aimed to a target of more prospective randomized studies are needed to 36–40 mmHg of CO2, and only a minority accept mild identify the correct level of PEEP in head-injured hypercapnia, even in the absence of intracranial patients. hypertension. Data from our survey show that hyperventilation is Regarding PaO2 level, the majority of respondents not often utilized in TBI patients. This is probably chose a target of 81–100 mmHg, greater than those used in ARDS patients (55–80 mmHg) and just a minority of respondents accept mild hypoxemia, especially in non- Table 3 Rescue strategies utilized in case of refractory specialized NICU centres [12]. This choice could be respiratory failure linked to the concern of hypoxia and its detrimental ef- Type of rescue strategy Respondents (n = 464) fects on brain-injured patients, but, on the other hand, - NMBAs 406 (88%) to the recent evidence regarding the risk related to - Recruitment manoeuvres 319 (69%) hyperoxia on critically ill patients [24–27]. - Prone position 292 (63%) Rescue strategies for refractory respiratory failure - Bronchoscopy 239 (52%) In case of refractory respiratory failure, several rescue - V-V ECMO 220 (47%) manoeuvres are generally employed as adjunct to in- - NO 115 (25%) vasive mechanical ventilation to ameliorate gas ex- - Extracorporeal CO2 removal (DECAP®) 39 (8%) change. NMBAs have been utilized in ARDS patients - Prostacycline 38 (8%) to improve gas exchange with inconclusive effects on Abbreviations: NMBAs neuromuscular blocking agents, V-V ECMO veno-venous mortality [28, 29]. Neuromuscular blockade is the extracorporeal membrane oxygenation, NO nitric oxide, CO2 carbon dioxide most frequently used rescue strategy by our Picetti et al. Critical Care (2020) 24:158 Page 7 of 9 respondents; this can be related to their possible heparin is necessary for this method with low risk of beneficial effect also on intracranial hypertension [30, bleeding, the efficacy of CO2 extracorporeal CO2 re- 31]. However, the utilization of NMBAs should take moval is limited and rarely used in the clinical prac- into account their side effects (such as muscle weak- tice [44]. ness) and should be reserved to the most severe cases Ventilatory strategies in trauma patients could take [30]. into account the phase of treatment and the underlying Recruitment manoeuvres can reduce atelectasis and injuries [45]. increase lung expiratory lung volumes with potential benefit on gas exchange and lung injury [32]. However, Limitations their use has been recently questioned by a recent study As with all methods of data collection, survey research showing an increase in mortality in ARDS patients also comes with a few drawbacks as inflexibility and val- undergoing lung recruitment manoeuvres and titrated idity. This survey presents also other limitations. First, PEEP (to the best respiratory system compliance) vs. low the response rate cannot be calculated considering the PEEP [33]. Recruitment manoeuvres can have potential design of this survey; in fact, ESICM members are in- side effects on the injured brain causing increased intra- vited to involve more participants locally, thus making thoracic pressure similar to the application of high level impossible to obtain the total number of people who re- of PEEP [34]. Despite these effects, they represent the ceived the survey. Second, respondents from specialized second most utilized rescue strategy in our survey. Data NICUs were included together with those working in are lacking about the optimal recruitment strategy in general ICUs. This might be considered a methodo- TBI patients with ARDS but in this context the use of logical limitation but, as TBI patients are treated world- neuromonitoring (i.e. ICP) seems to be mandatory to wide not only in specialized NICUs, we believe that our optimize systemic oxygenation without causing side approach produced more generalizable findings. Third, effects. this survey was developed by two investigators without a Prone position is frequently utilized in ARDS pa- prior systematic review of the literature or pilot testing tients because of its ability to improve ventilation/per- in a smaller sample of participants; this might further fusion ratio, to increase end-expiratory lung volume limit the quality of the questionnaire and data. Fourth, and to decrease VILI by ameliorating the distribution this survey refers only to physicians’ clinical practice in of the TV [32]. This manoeuvre is able to ameliorate respiratory management of TBI without including pa- mortality in ARDS only if applied for more than 12 tients’ data. h/day and in patients with a PaO2/FiO2 < 150 [32]. Small studies have been published so far involving pa- Conclusions tients with neurological damage; in this situation, des- In conclusion, this survey shows that important differ- pite an improvement in systemic/brain oxygenation, ences in the clinical practice in the ventilatory manage- an increase in ICP has been often observed [35–39]. ment of TBI patients with and without respiratory As consequence, patients with brain injury have been failure still exist. Lung-protective ventilation strategies generally excluded from the only available trial on seem to be more frequently applied in the clinical prac- prone position on ARDS patients [13]. tice in brain-injured patients, although most respondents Recently, extracorporeal membrane oxygenation still seem to have concerns regarding the use of high (ECMO) has been utilized as a rescue strategy in ARDS PEEP in case of intracranial hypertension. Future studies patients [39, 40]. Historically, ECMO was not utilized in are warranted to clarify the huge practice variability TBI patients because of the risk of cerebral bleeding re- among centres. lated to the use of anticoagulation. Recently, some case reports and small case series have suggested a potential Supplementary information beneficial use of ECMO in TBI patients [41]. Surpris- Supplementary information accompanies this paper at (https://doi.org/10. ingly, nearly half of our respondents would use ECMO 1186/s13054-020-02875-w). in TBI patients as rescue respiratory strategy. This could be related to the possibility to adopt heparin-free veno- Additional file 1. Appendix 1, Table S1, Table S2, − Table S3. (DOCX 40 kb) venous (VV) ECMO with consequent less risk of bleeding complications [42, 43]. However, the role of Abbreviations TBI: Traumatic brain injury; ARDS: Acute respiratory distress syndrome; ECMO in TBI patients with refractory respiratory ther- PaO2: Arterial partial pressure of oxygen; FiO2: Inspired fraction of oxygen; apy requires further investigations. ESICM: European Society of Intensive Care Medicine; PBW: Predicted body Finally, only a small amount of our respondents weight; PEEP: Positive end-expiratory pressure; ICU: Intensive care unit; TV: Tidal volume; CO2: Carbon dioxide; NICU: Neuro-ICU; PaCO2: Arterial suggested the use of extracorporeal CO2 removal (i.e. partial pressure of CO2; NMBAs: Neuromuscular blocking agent; DECAP®) in TBI patients; although a small dose of ICP: Intracranial pressure; CPP: Cerebral perfusion pressure; CBF: Cerebral Picetti et al. Critical Care (2020) 24:158 Page 8 of 9 blood flow; ECMO: Extracorporeal membrane oxygenation; VV: Veno-venous; 10. Frisvold SK, Robba C, Guérin C. 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The authors declare that they have no competing interests. 19. Robba C, Bragazzi NL, Bertuccio A, Cardim D, Donnelly J, Sekhon M, et al. Effects of prone position and positive end-expiratory pressure on Author details noninvasive estimators of ICP: a pilot study. J Neurosurg Anesthesiol. 2017; 1 Department of Anesthesia and Intensive Care, Parma University Hospital, Via 29(3):243–50. Gramsci 14, 43100 Parma, Italy. 2Department of Anesthesia and Intensive 20. Pelosi P, Rocco PRM, Gama de Abreu M. Close down the lungs and keep Care, IRCCS for Oncology and Neurosciences, Genoa, Italy. 3Department of them resting to minimize ventilator-induced lung injury. Crit Care. 2018; Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, 22(1):72. Italy. 4Department of Intensive Care, Erasme Hospital, Université Libre de 21. Coles JP, Fryer TD, Coleman MR, Smielewski P, Gupta AK, Minhas PS, Bruxelles (ULB), Brussels, Belgium. 5School of Medicine and Surgery, et al. 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