BACKGROUND
The occurrence of postoperative pulmonary complications is strongly associated with increased hospital mortality and prolonged postoperative hospital stay.(11 Mazo V, Sabaté S, Canet J, Gallart L, de Abreu MG, Belda J, et al. Prospective external validation of a predictive score for postoperative pulmonary complications. Anesthesiology. 2014;121(2):219-31.,22 Serpa Neto A, Hemmes SN, Barbas CS, Beiderlinden M, Fernandez-Bustamante A, Futier E, Hollmann MW, Jaber S, Kozian A, Licker M, Lin WQ, Moine P, Scavonetto F, Schilling T, Selmo G, Severgnini P, Sprung J, Treschan T, Unzueta C, Weingarten TN, Wolthuis EK, Wrigge H, Gama de Abreu M, Pelosi P, Schultz MJ; PROVE Network investigators. 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(12):1007-15.) Postoperative pulmonary complications could, at least in part be prevented by using so-called lung protective mechanical ventilation strategies, which may include use of low tidal volume (VT), positive end-expiratory pressure (PEEP) and low oxygen fractions (FiO2).(33 Serpa Neto A, Simonis FD, Schultz MJ. How to ventilate patients without acute respiratory distress syndrome? Curr Opin Crit Care. 2015;21(1):65-73.)
TIDAL VOLUMES
Anesthesiologists commonly used ventilation strategies with high VT during
general anesthesia for surgery because this strategy has the potential to re-open
those lung regions that collapse at end-expiration. This could reduce the need for
high FiO2, as it reduces ventilation-perfusion mismatch, and as such
prevent oxygen toxicity.(44 Bendixen HH, Hedley-Whyte J, Laver MB. Impaired oxygenation in surgical
patients during general anesthesia with controlled ventilation. A concept of
atelectasis. N Engl J Med. 1963;269:991-6.) Moreover, use of high VT was considered to be
safe since intraoperative ventilation usually only last hours. Animal research,
though, convincingly demonstrated that high VT ventilation in animals with
healthy lungs has a strong potential to cause lung injury, even when
short-lasting.(33 Serpa Neto A, Simonis FD, Schultz MJ. How to ventilate patients without
acute respiratory distress syndrome? Curr Opin Crit Care.
2015;21(1):65-73.)
Furthermore, one randomized controlled trial (RCT) comparing ventilation with low
VT (6mL/kg predicted body weight - PBW) with ventilation with high
VT (10mL/kg PBW) in critically ill patients with uninjured lungs
confirmed that ventilation with high VT induces lung
injury,(55 Determann RM, Royakkers A, Wolthuis EK, Vlaar AP, Choi G, Paulus F, et
al. Ventilation with lower tidal volumes as compared with conventional tidal volumes
for patients without acute lung injury: a preventive randomized controlled trial.
Crit Care. 2010;14(1):R1.) and
metaanalyses of observational studies showed an association between VT
size and duration of ventilation.(66 Serpa Neto A, Cardoso SO, Manetta JA, Pereira VG, Espósito DC,
Pasqualucci Mde O, et al. Association between use of lung-protective ventilation with
lower tidal volumes and clinical outcomes among patients without acute respiratory
distress syndrome: a meta-analysis. JAMA. 2012;308(16):1651-9.,77 Serpa Neto A, Simonis FD, Barbas CS, Biehl M, Determann RM, Elmer J, et
al. Association between tidal volume size, duration of ventilation, and sedation
needs in patients without acute respiratory distress syndrome: an individual patient
data meta-analysis. Intensive Care Med. 2014;40(7):950-7.) Several
small clinical trials of intraoperative ventilation further improved our
understanding of the harmful effects of high VT,(33 Serpa Neto A, Simonis FD, Schultz MJ. How to ventilate patients without
acute respiratory distress syndrome? Curr Opin Crit Care.
2015;21(1):65-73.) and recently three randomized
controlled trials convincingly showed that a ventilation strategy that uses low
VT prevents development of postoperative pulmonary
complications.(88 Severgnini P, Selmo G, Lanza C, Chiesa A, Frigerio A, Bacuzzi A, et al.
Protective mechanical ventilation during general anesthesia for open abdominal
surgery improves postoperative pulmonary function. Anesthesiology.
2013;118(6):1307-21.
9 Futier E, Constantin JM, Paugam-Burtz C, Pascal J, Eurin M, Neuschwander
A, Marret E, Beaussier M, Gutton C, Lefrant JY, Allaouchiche B, Verzilli D, Leone M,
De Jong A, Bazin JE, Pereira B, Jaber S; IMPROVE Study Group. A trial of
intraoperative low-tidal-volume ventilation in abdominal surgery. N Engl J Med.
2013;369(5):428-37.-1010 Ge Y, Yuan L, Jiang X, Wang X, Xu R, Ma W. [Effect of lung protection
mechanical ventilation on respiratory function in the elderly undergoing spinal
fusion]. Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2013;38(1):81-5.
Chinese.) Low
VT ventilation is becoming standard of care in the operation room, as
suggested by a report on intraoperative ventilation practices in a large number of
university hospitals in the USA showing that VT nearly halved over the
last decade, to 7 to 8mL/kg PBW.(1111 Wanderer JP, Ehrenfeld JM, Epstein RH, Kor DJ, Bartz RR,
Fernandez-Bustamante A, et al. Temporal trends and current practice patterns for
intraoperative ventilation at U.S. academic medical centers: a retrospective study.
BMC Anesthesiol. 2015;15:40.) It is possible, but certainly not proven, that a further
reduction of VT during intraoperative ventilation could even further
reduce development of postoperative pulmonary complications.
POSITIVE END-EXPIRATORY PRESSURE
Induction of anesthesia, especially when using high FiO2, has the
potential to induce atelectasis. Ventilation with low VT could further
increase alveolar instability.(1212 Dreyfuss D, Saumon G. Ventilator-induced lung injury: lessons from
experimental studies. Am J Respir Crit Care Med. 1998;157(1):294-323.
Review.) PEEP has the potential to open collapsed lung regions, and
could maintain the alveoli open during the whole breath cycle.(1212 Dreyfuss D, Saumon G. Ventilator-induced lung injury: lessons from
experimental studies. Am J Respir Crit Care Med. 1998;157(1):294-323.
Review.) However, anesthesiologists have
been reluctant to use PEEP since it could lead to cardiac compromise, mandating
volume expansion and perhaps even vasoactive drugs.(1313 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;384(9942):495-503.) Notably, in the randomized controlled trial
mentioned above comparing ventilation with a low VT (6mL/kg predicted PBW)
with ventilation with high VT (10mL/kg PBW) in critically ill patients
with uninjured lungs,(55 Determann RM, Royakkers A, Wolthuis EK, Vlaar AP, Choi G, Paulus F, et
al. Ventilation with lower tidal volumes as compared with conventional tidal volumes
for patients without acute lung injury: a preventive randomized controlled trial.
Crit Care. 2010;14(1):R1.)
an independent association between use of higher levels of PEEP and the development
of the acute respiratory distress syndrome was observed. The three RCTs of
intraoperative ventilation mentioned above actually compared bundles of
lung-protection: low VT with high levels of PEEP, and high VT
without PEEP.(88 Severgnini P, Selmo G, Lanza C, Chiesa A, Frigerio A, Bacuzzi A, et al.
Protective mechanical ventilation during general anesthesia for open abdominal
surgery improves postoperative pulmonary function. Anesthesiology.
2013;118(6):1307-21.
9 Futier E, Constantin JM, Paugam-Burtz C, Pascal J, Eurin M, Neuschwander
A, Marret E, Beaussier M, Gutton C, Lefrant JY, Allaouchiche B, Verzilli D, Leone M,
De Jong A, Bazin JE, Pereira B, Jaber S; IMPROVE Study Group. A trial of
intraoperative low-tidal-volume ventilation in abdominal surgery. N Engl J Med.
2013;369(5):428-37.-1010 Ge Y, Yuan L, Jiang X, Wang X, Xu R, Ma W. [Effect of lung protection
mechanical ventilation on respiratory function in the elderly undergoing spinal
fusion]. Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2013;38(1):81-5.
Chinese.) It is not possible to conclude
from these trials whether benefit was due to use of low VT or higher
levels of PEEP or both, but one recently published RCT in non-obese patients
undergoing planned abdominal surgery comparing intraoperative ventilation with low
levels of PEEP (0 - 2cmH2O) with high levels of PEEP (12cmH2O),
showed no differences between the two randomization arms with respect to the
occurrence of postoperative pulmonary complications.(1313 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;384(9942):495-503.) In that RCT, use of the higher PEEP levels was
associated with intraoperative hypotension and higher need for vasoactive
drugs.(1313 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;384(9942):495-503.) A recent
metaanalysis including data from the larger RCTs mentioned above and several other
investigations of ventilation in the operating room confirm that high levels of PEEP
do not prevent postoperative pulmonary complications when low VT are
used.(1414 Serpa Neto A, Hemmes SN, Barbas CS, Beiderlinden M, Biehl M, Binnekade
JM, et al. Protective versus conventional ventilation for surgery: a systematic
review and individual patient data meta-analysis. Anesthesiology. 2015 May 15. [Epub
ahead of print].) It could
very well be that a minimum of 2cmH2O of PEEP is sufficient in most
patients, and that further increases should be individualized, e.g., based on
oxygenation. We cannot exclude, though, that obese patients or patients undergoing
laparoscopic abdominal surgery during which insufflation of gas in the abdominal
cavity could induce more atelectasis, do benefit from higher levels of PEEP, but
randomized controlled trial evidence is lacking.
OXYGEN FRACTIONS
Seen the uncertainties surrounding the use of PEEP in the operation room, anesthesiologist may want to improve oxygenation with the use of higher FiO2, despite the fact that this could induce reabsorption atelectasis(33 Serpa Neto A, Simonis FD, Schultz MJ. How to ventilate patients without acute respiratory distress syndrome? Curr Opin Crit Care. 2015;21(1):65-73.) and increase the production of reactive oxygen which could injure cellular structures.(33 Serpa Neto A, Simonis FD, Schultz MJ. How to ventilate patients without acute respiratory distress syndrome? Curr Opin Crit Care. 2015;21(1):65-73.) There is increasing evidence that both ventilation with high FiO2 and/or high arterial oxygen levels are associated with increased mortality in critically ill patients, an effect that appears to be independent of other factors than disease severity.(33 Serpa Neto A, Simonis FD, Schultz MJ. How to ventilate patients without acute respiratory distress syndrome? Curr Opin Crit Care. 2015;21(1):65-73.) At present, there are no sufficiently powered trials that investigated the effects of higher FiO2 on occurrence of postoperative pulmonary complications. Despite the evidence for harm of high FiO2 in non-surgical patients, higher levels of FiO2 are increasingly used, as suggested by the report on intraoperative ventilation practices in university hospitals in the USA mentioned above.(1111 Wanderer JP, Ehrenfeld JM, Epstein RH, Kor DJ, Bartz RR, Fernandez-Bustamante A, et al. Temporal trends and current practice patterns for intraoperative ventilation at U.S. academic medical centers: a retrospective study. BMC Anesthesiol. 2015;15:40.)
FUTURE STUDIES
At present several RCTs of intra-operative ventilation are running, including the
international ‘Protective Ventilation With Higher Versus Lower PEEP During General
Anesthesia for Surgery in Obese Patients’ (PROBESE) trial,(1515 Schultz MJ. Protective Ventilation Network Projects [Internet]. 2015.
[cited 2015 Mai 21]. Available from:
https://sites.google.com/site/proveneteu/provenet-studies
https://sites.google.com/site/proveneteu...
) the French trial comparing
protective to conventional ventilation (VT of 5mL/kg PBW plus PEEP vs.
VT of 10mL/kg PBW without PEEP) in surgery for lung
cancer,(1515 Schultz MJ. Protective Ventilation Network Projects [Internet]. 2015.
[cited 2015 Mai 21]. Available from:
https://sites.google.com/site/proveneteu/provenet-studies
https://sites.google.com/site/proveneteu...
) and the
international ‘Protective Ventilation With Higher Versus Lower PEEP During General
Anesthesia for Thorax Surgery’ (PROTHOR).(1515 Schultz MJ. Protective Ventilation Network Projects [Internet]. 2015.
[cited 2015 Mai 21]. Available from:
https://sites.google.com/site/proveneteu/provenet-studies
https://sites.google.com/site/proveneteu...
) The results of these trials all have the potential to
further improve safety of intra-operative ventilation.
CONCLUSIONS
We advise to use low tidal volume, low levels of positive end-expiratory pressure, and low levels of low oxygen fractions during intra-operative ventilation.
-
Responsible editor: Jorge Ibrain Figueira Salluh
REFERÊNCIAS
-
1Mazo V, Sabaté S, Canet J, Gallart L, de Abreu MG, Belda J, et al. Prospective external validation of a predictive score for postoperative pulmonary complications. Anesthesiology. 2014;121(2):219-31.
-
2Serpa Neto A, Hemmes SN, Barbas CS, Beiderlinden M, Fernandez-Bustamante A, Futier E, Hollmann MW, Jaber S, Kozian A, Licker M, Lin WQ, Moine P, Scavonetto F, Schilling T, Selmo G, Severgnini P, Sprung J, Treschan T, Unzueta C, Weingarten TN, Wolthuis EK, Wrigge H, Gama de Abreu M, Pelosi P, Schultz MJ; PROVE Network investigators. 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(12):1007-15.
-
3Serpa Neto A, Simonis FD, Schultz MJ. How to ventilate patients without acute respiratory distress syndrome? Curr Opin Crit Care. 2015;21(1):65-73.
-
4Bendixen HH, Hedley-Whyte J, Laver MB. Impaired oxygenation in surgical patients during general anesthesia with controlled ventilation. A concept of atelectasis. N Engl J Med. 1963;269:991-6.
-
5Determann RM, Royakkers A, Wolthuis EK, Vlaar AP, Choi G, Paulus F, et al. Ventilation with lower tidal volumes as compared with conventional tidal volumes for patients without acute lung injury: a preventive randomized controlled trial. Crit Care. 2010;14(1):R1.
-
6Serpa Neto A, Cardoso SO, Manetta JA, Pereira VG, Espósito DC, Pasqualucci Mde O, et al. Association between use of lung-protective ventilation with lower tidal volumes and clinical outcomes among patients without acute respiratory distress syndrome: a meta-analysis. JAMA. 2012;308(16):1651-9.
-
7Serpa Neto A, Simonis FD, Barbas CS, Biehl M, Determann RM, Elmer J, et al. Association between tidal volume size, duration of ventilation, and sedation needs in patients without acute respiratory distress syndrome: an individual patient data meta-analysis. Intensive Care Med. 2014;40(7):950-7.
-
8Severgnini P, Selmo G, Lanza C, Chiesa A, Frigerio A, Bacuzzi A, et al. Protective mechanical ventilation during general anesthesia for open abdominal surgery improves postoperative pulmonary function. Anesthesiology. 2013;118(6):1307-21.
-
9Futier E, Constantin JM, Paugam-Burtz C, Pascal J, Eurin M, Neuschwander A, Marret E, Beaussier M, Gutton C, Lefrant JY, Allaouchiche B, Verzilli D, Leone M, De Jong A, Bazin JE, Pereira B, Jaber S; IMPROVE Study Group. A trial of intraoperative low-tidal-volume ventilation in abdominal surgery. N Engl J Med. 2013;369(5):428-37.
-
10Ge Y, Yuan L, Jiang X, Wang X, Xu R, Ma W. [Effect of lung protection mechanical ventilation on respiratory function in the elderly undergoing spinal fusion]. Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2013;38(1):81-5. Chinese.
-
11Wanderer JP, Ehrenfeld JM, Epstein RH, Kor DJ, Bartz RR, Fernandez-Bustamante A, et al. Temporal trends and current practice patterns for intraoperative ventilation at U.S. academic medical centers: a retrospective study. BMC Anesthesiol. 2015;15:40.
-
12Dreyfuss D, Saumon G. Ventilator-induced lung injury: lessons from experimental studies. Am J Respir Crit Care Med. 1998;157(1):294-323. Review.
-
13PROVE 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;384(9942):495-503.
-
14Serpa Neto A, Hemmes SN, Barbas CS, Beiderlinden M, Biehl M, Binnekade JM, et al. Protective versus conventional ventilation for surgery: a systematic review and individual patient data meta-analysis. Anesthesiology. 2015 May 15. [Epub ahead of print].
-
15Schultz MJ. Protective Ventilation Network Projects [Internet]. 2015. [cited 2015 Mai 21]. Available from: https://sites.google.com/site/proveneteu/provenet-studies
» https://sites.google.com/site/proveneteu/provenet-studies
Publication Dates
-
Publication in this collection
Apr-Jun 2015
History
-
Received
13 May 2015 -
Accepted
01 June 2015