Keeping the lung open is a key strategy to prevent postoperative pulmonary complications
It is well established that Postoperative Pulmonary Complications (PPCs) significantly contribute to perioperative morbidity and mortality, as well as to postoperative length of hospital stay 1-3. PPCs relate to anesthesia and/or surgery, and occur within a time frame of 5 to 7 days after surgery 7,8. They lack a uniform definition and include a range of rather mild to very severe events (e.g. need for supplemental oxygen, respiratory failure, atelectasis and Acute Respiratory Distress Syndrome (ARDS)). PPCs represent the major cause of death after both cardiothoracic and non-cardiothoracic surgery and thus pose a significant burden to society 9-12. The incidence of PPCs after general surgeries is 5–10% 3,13,14, while it has been reported to be as high as 30–40% after abdominal and intrathoracic surgeries 1,3,13, and even 87% after liver transplantation 15. Of note, a large multicenter study has revealed that up to one in every five patients who develops a severe PPC dies within 30 days of surgery, and patients who survive often suffer from a sustained reduction in functional status 3.
Several investigations have aimed to define reliable risk factors for the development of PPCs 1,3-5,14,16-20. While the ‘Surgical Lung Injury Prediction’ (SLIP and SLIP-2) model 17,19 and the ‘Assess Respiratory Risk in Surgical Patients in Catalonia’ (ARISCAT) risk score 1,3 represent prediction tools that are based on patient characteristics and preoperatively assessable surgery-related features, the recently published ‘Local Assessment of Ventilatory Management during General Anesthesia for surgery’ (LAS VEGAS) prediction score 14 additionally includes intraoperative events. These have been implicated as contributing to postoperative complications 21. Of note, intraoperative desaturation has been shown to be significantly associated with the development of PPCs, which could reflect the occurrence of atelectasis during ventilation, resulting in the decrease of functional residual capacity 14. Thus, perioperative ventilation approaches should ideally include adequate strategies to prevent atelectasis and desaturation 22.
Multiple randomized controlled trials have been conducted to evaluate the effect of different ventilation strategies on the development of PPCs. The majority of these interventions aimed to keep the lung open by applying recruitment maneuvers or setting higher PEEP levels, usually in combination with low tidal volumes. While some of these trials failed to show improved patient outcome 23,24, some did show positive effects 25-30, and some are still ongoing 31,32. Thus, these studies aimed to reduce PPCs by focusing on the optimization of established ventilation parameters like pressures and volumes for specific patient groups, where an overall consensus is still lacking. This may indicate that a more fundamental change in ventilation strategies is required to improve patient outcome and prevent PPCs.
FCV® keeps the lung open and results in higher efficiency of ventilation than conventional ventilation strategies
The new ventilation method FCV®, solely applied by Evone, keeps the lungs open by controlling the full ventilation cycle. As depicted in Figure 1, FCV® relies on a continuous inspiratory and expiratory flow without notable pauses 33, which are present during Volume Controlled Ventilation (VCV) and Pressure Controlled Ventilation (PCV) at the end of inspiration and expiration. FCV® aims for a linear increase or decrease in intratracheal pressure, without sudden pressure changes as compared to conventional methods. A controlled and linearized airway pressure decline has been described to induce a recruiting effect 34. Thus, FCV® prevents the bronchioles and alveoli from collapsing at the end of expiration, enhancing oxygen uptake into the blood as well as CO2 removal.
Figure 1. Intratracheal/airway pressure, flow and volume curves for FCV®, VCV and PCV (see also Schmidt et al. 2019 37)
Animal studies revealed a significantly higher ventilation efficiency of FCV® compared to the current golden standard VCV. In lung-healthy pigs, FCV® resulted in a 9% increase (P=0.002) in arterial oxygenation while using a 21% lower minute volume (P=0.02) for normoventilation as compared to VCV with similar PEEP and tidal volume settings 35. Analysis of dynamic computer tomography (CT) scans revealed that these effects were related to a better lung recruitment (Figure 2). These results were even more striking in a porcine model of acute respiratory distress syndrome (ARDS): Compared to VCV, with comparable tidal volumes and PEEP, FCV® led to a 46% increase of arterial oxygenation (P=0.035) while using a 26% lower minute volume (P<0.001) 36. In these lung-sick animals, FCV® prevented atelectasis and facilitated normal aeration in dependent (dorsal) lung parts.
Figure 2. Improved lung aeration during FCV® vs. VCV in healthy pigs, measured by Hounsfield units during dynamic computer tomography (adapted from Schmidt et al. 2018 35)
FCV® has been applied clinically in more than 40 hospitals across 11 countries. A first multicenter observational study in ENT patients revealed that FCV® using Evone and Tritube resulted in adequate etCO2 levels with minute volume in the lower normal range and driving pressures in the normal range. It was concluded that FCV® provides a new option for mechanical ventilation and that the narrow-bore tube expands the armamentarium for airway management 37.
A randomized controlled trial in laryngeal surgical patients, aiming to evaluate surgical exposure comparing Tritube with an Microlaryngeal Tube (MLT)-6, demonstrated that FCV® improved alveolar recruitment and consequently enhanced respiratory system compliance compared to VCV (63±14 vs. 46±8 ml/cmH2O, P<0.001) 38. In the same line, FCV® better maintained end-expiratory lung volume in morbidly obese patients as compared to VCV (P<0.001) during ventilation phases of only 7 minutes, with similar tidal volumes, but lower peak inspiratory pressures 39. These results strongly implicate a recruiting effect due to the constant expiratory flow and the elevated mean airway pressure 39. Furthermore, a crossover randomized controlled trial in lung-healthy patients revealed higher efficiency of ventilation when using FCV® compared to VCV 40. With similar tidal volumes and peak pressures, FCV® resulted in a 9% higher oxygenation and 4% lower arterial CO2 concentration (P<0.001), while maintaining a 10% higher mean tracheal pressure (P<0.001) 40. Together, these studies underline the higher efficiency of ventilation by FCV® as compared to VCV and indicate that FCV® may help prevent atelectasis and hypoxemia in patients during mechanical ventilation.
- Mazo V, Sabaté S, et al. Prospective external validation of a predictive score for postoperative pulmonary complications. Anesthesiology. Anesthesiology. 2014 Aug;121(2):219-31.
- Serpa Neto A, Hemmes SN, et al. Incidence of mortality and morbidity related to postoperative lung injury in patients who have undergone abdominal or thoracic surgery: a systematic review and meta-analysis. Lancet Respir Med. 2014;2:1007–15.
- Canet J, Gallart L, et al; ARISCAT Group. Prediction of postoperative pulmonary complications in a population-based surgical cohort. Anesthesiology. 2010 Dec;113(6):1338-50.
- Canet J, Sabaté S, et al. Development and validation of a score to predict postoperative respiratory failure in a multicentre European cohort: a prospective, observational study. Eur J Anaesthesiol. 2015;32:458–70.
- Güldner A, Kiss T, Serpa Neto A, Hemmes SN, Canet J, Spieth PM, Rocco PR, Schultz MJ, Pelosi P, Gama de Abreu M. Intraoperative protective mechanical ventilation for prevention of postoperative pulmonary complications: a comprehensive review of the role of tidal volume, positive end-expiratory pressure, and lung recruitment maneuvers. Anesthesiology. 2015 Sep;123(3):692-713. doi: 10.1097/ALN.0000000000000754. Review. PubMed PMID: 26120769
- Weiser TG, Makary MA, et al; Standardised metrics for global surgical surveillance. Lancet. 2009;374:1113–7.
- Canet J, Gallart L. Postoperative respiratory failure: pathogenesis, prediction, and prevention. Curr Opin Crit Care. 2014 Feb;20(1):56-62. doi: 10.1097/MCC.0000000000000045. Review. PubMed PMID: 24240985.
- Jammer I, Wickboldt N, Sander M, Smith A, Schultz MJ, Pelosi P, Leva B, Rhodes A, Hoeft A, Walder B, Chew MS, Pearse RM; European Society of Anaesthesiology (ESA) and the European Society of Intensive Care Medicine (ESICM); European Society of Anaesthesiology; European Society of Intensive Care Medicine. Standards for definitions and use of outcome measures for clinical effectiveness research in perioperative medicine: European Perioperative Clinical Outcome (EPCO) definitions: a statement from the ESA-ESICM joint taskforce on perioperative outcome measures. Eur J Anaesthesiol. 2015 Feb;32(2):88-105. doi: 10.1097/EJA.0000000000000118. PubMed PMID: 25058504.
- Amar D, Munoz D, Shi W, Zhang H, Thaler HT. A clinical prediction rule for pulmonary complications after thoracic surgery for primary lung cancer. Anesth Analg. 2010 May 1;110(5):1343-8. doi: 10.1213/ANE.0b013e3181bf5c99. Epub 2009 Oct 27. PubMed PMID: 19861366.
- Rahmanian PB, Kröner A, Langebartels G, Özel O, Wippermann J, Wahlers T. Impact of major non-cardiac complications on outcome following cardiac surgery procedures: logistic regression analysis in a very recent patient cohort. Interact Cardiovasc Thorac Surg. 2013 Aug;17(2):319-26; discussion 326-7. doi: 10.1093/icvts/ivt149. Epub 2013 May 10. PubMed PMID: 23667066; PubMed Central PMCID: PMC3715168.
- Lawrence VA, Hilsenbeck SG, Mulrow CD, Dhanda R, Sapp J, Page CP. Incidence and hospital stay for cardiac and pulmonary complications after abdominal surgery. J Gen Intern Med. 1995 Dec;10(12):671-8. PubMed PMID: 8770719.
- Smetana GW, Lawrence VA, Cornell JE; American College of Physicians. Preoperative pulmonary risk stratification for noncardiothoracic surgery: systematic review for the American College of Physicians. Ann Intern Med. 2006 Apr 18;144(8):581-95. Review. PubMed PMID: 16618956.
- Khuri SF, Henderson WG, DePalma RG, Mosca C, Healey NA, Kumbhani DJ; Participants in the VA National Surgical Quality Improvement Program. Determinants of long-term survival after major surgery and the adverse effect of postoperative complications. Ann Surg. 2005 Sep;242(3):326-41; discussion 341-3. PubMed PMID: 16135919; PubMed Central PMCID: PMC1357741.
- LAS VEGAS investigators. Epidemiology, practice of ventilation and outcome for patients at increased risk of postoperative pulmonary complications: LAS VEGAS – an observational study in 29 countries. Eur J Anaesthesiol. 2017 Aug;34(8):492-507. doi: 10.1097/EJA.0000000000000646. PubMed PMID: 28633157; PubMed Central PMCID: PMC5502122.
- De Gasperi Feltracco P, Ceravola E, Mazza E. Pulmonary complications in patients receiving a solid-organ transplant, Crit Care 2014; 20 (4) 411-419.
- McAlister FA, Bertsch K, Man J, Bradley J, Jacka M. Incidence of and risk factors for pulmonary complications after nonthoracic surgery. Am J Respir Crit Care Med. 2005 Mar 1;171(5):514-7. Epub 2004 Nov 24. PubMed PMID: 15563632.
- Kor DJ, Warner DO, Alsara A, Fernández-Pérez ER, Malinchoc M, Kashyap R, Li G, Gajic O. Derivation and diagnostic accuracy of the surgical lung injury prediction model. Anesthesiology. 2011 Jul;115(1):117-28. doi: 10.1097/ALN.0b013e31821b5839. PubMed PMID: 21694510; PubMed Central PMCID: PMC3986041.
- Canet J, Gallart L. Predicting postoperative pulmonary complications in the general population. Curr Opin Anaesthesiol. 2013 Apr;26(2):107-15. doi: 10.1097/ACO.0b013e32835e8acd. Review. PubMed PMID: 23407154.
- Kor DJ, Lingineni RK, Gajic O, Park PK, Blum JM, Hou PC, Hoth JJ, Anderson HL 3rd, Bajwa EK, Bartz RR, Adesanya A, Festic E, Gong MN, Carter RE, Talmor DS. Predicting risk of postoperative lung injury in high-risk surgical patients: a multicenter cohort study. Anesthesiology. 2014 May;120(5):1168-81. doi: 10.1097/ALN.0000000000000216. PubMed PMID: 24755786; PubMed Central PMCID: PMC3999474.
- Futier E, Marret E, Jaber S. Perioperative positive pressure ventilation: an integrated approach to improve pulmonary care. Anesthesiology. 2014 Aug;121(2):400-8. doi: 10.1097/ALN.0000000000000335. Review. PubMed PMID: 25050494.
- Riss S, Mittlböck M, Riss K, Chitsabesan P, Stift A. Intraoperative complications have a negative impact on postoperative outcomes after rectal cancer surgery. Int J Surg. 2014;12(8):833-6. doi: 10.1016/j.ijsu.2014.07.003. Epub 2014 Jul 9. PubMed PMID: 25014647.
- O’Gara B, Talmor D. Perioperative lung protective ventilation. BMJ. 2018 Sep 10;362:k3030. doi: 10.1136/bmj.k3030. Review. PubMed PMID: 30201797.
- PROVE Network Investigators for the Clinical Trial Network of the European Society of Anaesthesiology, Hemmes SN, Gama de Abreu M, Pelosi P, Schultz MJ. High versus low positive end-expiratory pressure during general anaesthesia for open abdominal surgery (PROVHILO trial): a multicentre randomised controlled trial. Lancet. 2014 Aug 9;384(9942):495-503. doi: 10.1016/S0140-6736(14)60416-5. Epub 2014 Jun 2. PubMed PMID: 24894577.
- Treschan TA, Kaisers W, Schaefer MS, Bastin B, Schmalz U, Wania V, Eisenberger CF, Saleh A, Weiss M, Schmitz A, Kienbaum P, Sessler DI, Pannen B, Beiderlinden M. Ventilation with low tidal volumes during upper abdominal surgery does not improve postoperative lung function. Br J Anaesth. 2012 Aug;109(2):263-71. doi: 10.1093/bja/aes140. Epub 2012 Jun 1. PubMed PMID: 22661750.
- Sundar S, Novack V, Jervis K, Bender SP, Lerner A, Panzica P, Mahmood F, Malhotra A, Talmor D. Influence of low tidal volume ventilation on time to extubation in cardiac surgical patients. Anesthesiology. 2011 May;114(5):1102-10. doi: 10.1097/ALN.0b013e318215e254. PubMed PMID: 21430518; PubMed Central PMCID: PMC3500383.
- Unzueta C, Tusman G, Suarez-Sipmann F, Böhm S, Moral V. Alveolar recruitment improves ventilation during thoracic surgery: a randomized controlled trial. Br J Anaesth. 2012 Mar;108(3):517-24. doi: 10.1093/bja/aer415. Epub 2011 Dec 26. PubMed PMID: 22201185.
- Severgnini P, Selmo G, Lanza C, Chiesa A, Frigerio A, Bacuzzi A, Dionigi G, Novario R, Gregoretti C, de Abreu MG, Schultz MJ, Jaber S, Futier E, Chiaranda M, Pelosi P. Protective mechanical ventilation during general anesthesia for open abdominal surgery improves postoperative pulmonary function. Anesthesiology. 2013 Jun;118(6):1307-21. doi: 10.1097/ALN.0b013e31829102de. PubMed PMID: 23542800.
- Futier E, Pereira B, Jaber S. Intraoperative low-tidal-volume ventilation. N Engl J Med. 2013 Nov 7;369(19):1862-3. doi: 10.1056/NEJMc1311316. PubMed PMID: 24195559.
- Park SH. Perioperative lung-protective ventilation strategy reduces postoperative pulmonary complications in patients undergoing thoracic and major abdominal surgery. Korean J Anesthesiol. 2016 Feb;69(1):3-7. doi: 10.4097/kjae.2016.69.1.3. Epub 2016 Jan 28. Review. PubMed PMID: 26885294; PubMed Central PMCID: PMC4754263
- Choi ES, Oh AY, In CB, Ryu JH, Jeon YT, Kim HG. Effects of recruitment manoeuvre on perioperative pulmonary complications in patients undergoing robotic assisted radical prostatectomy: A randomised single-blinded trial. PLoS One. 2017 Sep 6;12(9):e0183311. doi: 10.1371/journal.pone.0183311. eCollection 2017. PubMed PMID: 28877238; PubMed Central PMCID: PMC5587235.
- Bluth T, Teichmann R, Kiss T, Bobek I, Canet J, Cinnella G, De Baerdemaeker L, Gregoretti C, Hedenstierna G, Hemmes SN, Hiesmayr M, Hollmann MW, Jaber S, Laffey JG, Licker MJ, Markstaller K, Matot I, Müller G, Mills GH, Mulier JP, Putensen C, Rossaint R, Schmitt J, Senturk M, Serpa Neto A, Severgnini P, Sprung J, Vidal Melo MF, Wrigge H, Schultz MJ, Pelosi P, Gama de Abreu M; PROBESE investigators; PROtective VEntilation Network (PROVEnet); Clinical Trial Network of the European Society of Anaesthesiology (ESA). Protective intraoperative ventilation with higher versus lower levels of positive end-expiratory pressure in obese patients (PROBESE): study protocol for a randomized controlled trial. Trials. 2017 Apr 28;18(1):202. doi: 10.1186/s13063-017-1929-0. Erratum in: Trials. 2017 Jun 1;18(1):247. PubMed PMID: 28454590; PubMed Central PMCID: PMC5410049.
- English translation “Method and device for ventilating a patient”, D. Enk. Priority March 2016
- Wirth S, Springer S, Spaeth J, Borgmann S, Goebel U, Schumann S. Application of the Novel Ventilation Mode FLow-Controlled EXpiration (FLEX): A Crossover Proof-of-Principle Study in Lung-Healthy Patients. Anesth Analg. 2017 Oct;125(4):1246-1252.
- Schmidt J, Wenzel C, Mahn M, Spassov S, Schmitz HC, Borgmann S, Lin Z, Haberstroh J, Meckel S, Eiden S, Wirth S, Buerkle H, Schumann S. Improved lung recruitment and oxygenation during mandatory ventilation with a new expiratory ventilation assistance device: A controlled interventional trial in healthy pigs. Eur J Anaesthesiol. 2018 Oct 35(10):736-744.
- Schmidt J, Wenzel C, Spassov S, Wirth S, Schumann S. Expiratory Ventilation Assistance during mandatory ventilation in porcine ARDS improves arterial oxygenation – a randomised controlled animal study [Abstract]. Eur J Anaesthesiol 2018; 35 e-supplement 56: 7
- Schmidt J, Günther F, Weber J, Wirth S, Brandes I, Barnes T, Zarbock A, Schumann S, Enk D. Flow-controlled ventilation during ear, nose and throat surgery. A prospective observational study. Eur J Anaesthesiol. ePub 2019 Feb 5.
- Schmidt J, Günther F, Weber J, Wirth S, Schumann s. Improved airway management and ventilation with a cuffed endotracheal tube with an outer diameter of 4.4 mm for laryngeal surgery – a randomized controlled trial. Euroanaesthesia 2019, Abstract 3269.
- Weber J, Straka L, Schmidt J, Borgmann S, Wirth S, Schumann S. Flow-controlled ventilation improves end-expiratory lung volume in obese patients – a crossover controlled interventional trial. Euroanaesthesia 2019, Abstract 3315.
- Weber J, Schmidt J, Straka LMM, Wirth S, Schumann S. Flow-controlled ventilation improves oxygenation in mechanically ventilated lung-healthy patients – a crossover controlled interventional trial. Euroanaesthesia 2019, Abstract 3301.
- Kristensen MS, Abildstrøm HH. Endotracheal video-laryngoscope guided intubation with a 2.4 mm cuff’ed tube and active expiration by a dedicated ventilator versus a standard tube/ventilator. A randomized single blinded study in patients with a predicted difficult airway. – A paradigm shift in airway management? Euroanaesthesia 2019, Abstract 3755.
Symposium Flow Controlled Ventilation blowing away VILI Erasmus Medical Center (Rotterdam, the Netherlands) is organizing a hybrid symposium on Fow Controlled Ventilation blowing away VILI. The event will be held on the 28th of October in Rotterdam but...