Discussion
We used a Delphi process to design a care bundle (POPC-CB), for patients at moderate to high risk of post-operative pulmonary complications which may have the potential to improve clinical outcomes. The proposed interventions are implemented throughout the perioperative journey: prior to the operation, supervised exercise programme and inspiratory muscle training, and during the operation, low tidal volume ventilation with individualised PEEP, use of routine monitoring to avoid hyperoxia and efforts made to limit neuromuscular blockade, and also post-operatively, deep breathing exercises and mandatory elevation of the head of the bed.
The quality and extent of clinical evidence to support each of the proposed components of the POPC-CB is variable. The Delphi process did not involve a formal evaluation of the strength of evidence for the interventions included in the care bundle, nor for those that were rejected. Some of the individual interventions have been evaluated by others using GRADE or Jadad methodologies (Guyatt et al.
2011; Jadad et al.
1996). A Cochrane review of preoperative inspiratory muscle training demonstrated efficacy at reducing POPC (Katsura et al.
2015). Using GRADE criteria, the Cochrane reviewers suggested the strength of evidence for pneumonia reduction was moderate whilst the strength of evidence for atelectasis and adverse event reduction was low and recommended caution due to the potential for overestimation of treatment effect. Although our Delphi process supports the inclusion of supervised preoperative exercise programme, the evidence for improved postoperative clinical outcomes is limited (O’Doherty et al.
2013). A meta-analysis of nine prehabilitation trials in 435 abdominal surgery patients suggests that supervised exercise can reduce overall postoperative complications, and five of these studies specifically demonstrated a reduction in postoperative pulmonary complications (Moran et al.
2016). A very low quality rating was observed using GRADE criteria due to the small sample sizes and significant risk of bias. Furthermore, the precise components of such a supervised programme have not been fully evaluated in relation to POPC reduction.
Protective lung ventilation strategies incorporating tidal volumes 5–8 mL/kg, higher PEEP and control of plateau pressure are beneficial in critically ill patients with acute lung injury or ARDS (Villar et al.
2006; Petrucci and Iacovelli
2007). In ICU patients without ARDS, a protective lung strategy reduced pulmonary and systemic inflammation and reduced the development of lung injury (Determann et al.
2010). A meta-analysis of 20 studies, using GRADE criteria, suggested the evidential strength for protective lung strategy in patients without ARDS to be moderate and high in reducing lung injury and mortality, respectively, but low in preventing pneumonia (Neto et al.
2012). These findings from critical care patients led to perioperative research exploring whether protective lung ventilation has a role during major surgery. The IMPROVE trial compared a ‘protective’ strategy of tidal volume 6–8 mL/kg ideal body weight, PEEP 6–8 cm H
2O, recruitment manoeuvers every 30 min with ‘conventional’ management of tidal volume 10–12 mL/kg, and PEEP and recruitment manoeuvers at clinicians’ discretion. The protective strategy was associated with a reduction in a composite of pulmonary and septic complications (Futier et al.
2013a). In another trial, PROVHILO, all patients received tidal volumes 8 mL/kg and were randomly assigned to either rather high PEEP of 12 and regular recruitment manoeuvers or to low PEEP 0–2. The result shows no difference in post-operative pulmonary complications but shows increased adverse events in the high PEEP group (Prove Network Investigators for the Clinical Trial Network of the European Society of Anaesthesiology et al.
2014). Even in critically ill ventilated ARDS patients, high versus very high PEEP levels was not shown to influence outcome (Brower et al.
2004). A meta-analysis of 15 studies investigating protective lung ventilation involving 2127 surgical patients concluded that intraoperative low tidal volume is associated with less pulmonary complications but no difference in mortality and length of hospital stay (Neto et al.
2015). The authors used the Jadad criteria to rate the quality of this evidence with seven studies scoring 4/5, seven 3/5 and one 2/5. Our Delphi consensus suggests low tidal volumes for all patients with individualised PEEP and recruitment manoeuvres at the discretion of the attending anaesthetist.
Inadequate reversal of neuromuscular blockade is associated with POPC. Post-operative residual curarization (PORC) is the incomplete recovery of muscle function following perioperative use of neuromuscular blocking agents. The prevalence of PORC is anything between 4 and 45%, when defined as train-of-four < 0.9 and is associated with adverse outcomes including POPC (Berg et al.
1997). Whilst the Delphi consensus recommendation is to limit neuromuscular blockade by careful monitoring of neuromuscular function and effective reversal, we acknowledge that ongoing research assessing the impact of neuromuscular blockade on POPC is awaiting publication and no specific drug or technique can be recommended. The potential for hyperoxia to cause harm is contentious. The association between hyperoxia and atelectasis is well established, although the magnitude of this effect may be overestimated (Pryor et al.
2004). A meta-analysis of 17 randomised controlled trials with 8093 mixed surgical patients used the Jadad score to assess quality and found six studies scored 5/5, four 4/5 and 7 less than 4, with sub-group analysis suggesting that hyperoxia can reduce surgical site infection in colorectal surgery patients (Yang et al.
2016).
Post-operative care from a specialist physiotherapist is a commonplace; however, the interventions delivered by physiotherapists vary significantly, and there is a scarcity of good-quality clinical evidence to inform practice with many small, underpowered studies using inadequate randomisation and unclear interventions (ÖRman and Westerdahl
2010; Pasquina et al.
2006). The incremental benefit of the proposed deep breathing exercises is uncertain, particularly when other aspects of post-operative physiotherapy, such as early mobilisation, are provided (Mackay et al.
2005). A Cochrane review of post-operative incentive spirometry following upper abdominal surgery described a small number of poor-quality studies which were unable to demonstrate any effect on postoperative complications (do Nascimento Junior et al.
2014). Elevation of the head of the bed, allowing gravity to help minimise pulmonary aspiration of oropharyngeal secretions and perhaps improve effectiveness of coughing, has been shown to reduce ventilator-associated pneumonia in critically ill patients although no evidence is available in POPC reduction (Wang et al.
2016).
I COUGH, a post-operative pulmonary care bundle, demonstrated a trend towards reduction in POPC (Cassidy et al.
2013). I COUGH incorporates Incentive spirometry, Coughing and deep breathing, Oral hygiene, Understanding (patient education), Get up (mobilisation) and Head of bed elevation. I COUGH was applied to all patients, not just those at high risk of POPC, and it was evaluated in a single centre and was evaluated prior to widespread adoption of enhanced recovery pathways. Our POPC-CB is designed to supplement established guidelines for enhanced recovery, not replace them (Lassen et al.
2009; ERAS society guidelines
n.d.). Although this protocol is designed for all patients undergoing major surgery, elements of ERAS pathways are relevant to reducing the incidence of POPC. These include optimal analgesia, avoidance of nasogastric tubes and bowel preparation, minimisation of ‘nil by mouth’, avoidance of sodium and water overload, routine early post-operative mobilisation, multi-modal analgesia and prevention of nausea and vomiting. A quality improvement programme incorporating ICOUGH into ERAS pathways has reduced POPC over time (Moore et al.
2017).
Strengths and limitations
An expert consensus using Delphi techniques is fundamentally dissimilar to a systematic review of evidence, and this is both a strength and a weakness. We made no attempt to inform or influence the experts, and the POPC-CB reflects opinions not necessarily supported by clinical evidence. Several components in this proposed CB have been the subject of detailed studies whilst others such as high-flow nasal oxygen and continuous positive airway pressure are under evaluation (Futier et al.
2013b). Conversely, some interventions that were considered but not selected for the POPC-CB have good evidence of clinical efficacy such as perioperative oral decontamination (Spreadborough et al.
2016).
During the Delphi process, ‘avoiding hyperoxia’ (excessively high partial pressure of oxygen, measured directly or detected from pulse oximetry) as an intra-operative component proved controversial leading to one expert withdrawing from the consensus amid concerns that some clinicians may misinterpret this component as ‘permissive hypoxaemia’ or avoidance of high inspired oxygen during critical airway interventions such as intubation. We believe that avoiding hypoxaemia is a fundamental part of anaesthetic management and therefore should not require inclusion within the POPC-CB.
Research recommendations
Prior to an evaluation of the clinical effectiveness of this POPC-CB, it is necessary to gain more information about the uptake of enhanced recovery programmes and, more specifically, the feasibility of undertaking this study. Only 50% of survey respondents screen patients for POPC risk, and a consistent screening of all patients needs to be implemented. Consistent delivery of all aspects of the care bundle will need to be specified, for example, what is meant by ‘supervised exercise programme’. It is uncertain to what extent these measures are part of routine clinical practice. Recent data from the UK suggest that protective lung ventilation in major open abdominal surgery is rarely used (Patel et al.
2016). Robust collection of post-operative outcome data, using standardised measures, is essential, and this may require additional local resources (Myles et al.
2016). Alternatively, large databases of surgical patients could potentially relate provision of POPC-CB components to the incidence of POPC.
Acknowledgements
The POPC-CB investigators:
Belda, F. Javier
Department of Surgery, University of Valencia, Valencia, Spain
Blobner, Manfred
Klinik für Anaesthesiologie
Technische Universität München
München
Blot, Stijn
Dept. of Internal Medicine, Ghent University, Ghent, Belgium and Burns Trauma & Critical Care Research Centre, The University of Queensland, Brisbane, Australia
Bugedo, Guillermo
Professor, Department of Intensive Care Medicine
Pontificia Universidad Catolica de Chile
Cabrini, Luca MD
Department of Anaesthesia and Intensive Care
Ospedale Istituto Scientifico San Raffaele, Milan, Italy
Canet, Jaume PhD
Chief of Department of Anaesthesiology
Hospital Universitari Germans Trias i Pujol
Barcelona, Spain
Chiumello, Davide
Dipartimento di Anestesia, Rianimazione ed Emergenza-Urgenza, Fondazione IRCCS Ca′ Granda - Ospedale Maggiore Policlinico, Milano, Italy
Engoren, Milo MD
Department of Anesthesiology
University of Michigan
Gallart, Lluis Tenured Professor
Department of Anesthesiology, Hospital del Mar. IMIM. Universitat Autonoma de Barcelona, Barcelona
G. Cosío, Borja MD, PhD
Director, Research Unit
Department of Respiratory Medicine
Hospital Universitario Son Espases
Spain
Guérin, Claude
University of Lyon and INSERM 955 Créteil, France
Jachymiak, Izabela
Department of Anesthesiology and Intensive Care - Podhalański Specialist Hospital. Pope John Paul II in Nowy Targ
Jammer, Ib
Department of Clinical Medicine, University of Bergen, Bergen, Norway
Department of Anaesthesiology and Intensive Care, Haukeland University Hospital, Bergen, Norway
Lamas, Cristiane da Cruz MD MRCP PhD
Instituto Nacional de Cardiologia and Unigranrio, Rio de Janeiro, Brazil
Makowski, Arystarch MD, PhD
Consultant in Anaesthesia and Critical Care
Medway NHS Foundation Trust
Malbouisson, Luiz Marcelo MD, PhD
Divisão de Anestesiologia
Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo
Matamis, D
ICU Head
Papageorgiou Hospital, Thessaloniki, Greece
Moonesinghe, Ramani
FRCA MRCP FFICM MD (Res)
Consultant in Anaesthesia and Intensive Care Medicine, UCLH
Hon Senior Lecturer in Anaesthesia, UCL
Moore, John
Clinical Director
Adult Critical care
Manchester Royal Infirmary
Mythen, Monty MBBS MD FRCA FFICM FCAI (Hon)
Smiths Medical Professor of Anaesthesia and Critical Care, University College London
Paugam-Burtz, C
Departement of Anesthesiology and perioperative care medicine
Hôpital Beaujon, HUPNVS APHP
Pearse, Rupert MD FRCA FFICM
NIHR Research Professor & Consultant in Intensive Care Medicine
Queen Mary University of London
Pelosi, Paolo MD, FERS
Department of Surgical Sciences and Integrated Diagnostics, IRCCS AOU San Martino IST, University of Genoa, Genoa, Italy
Poelaert, Jan MD, PhD
Chair and Director
Department of Anesthesiology and Perioperative Medicine; Acute and Chronic Pain Therapy
Universitair Ziekenhuis Brussel
Ponssen, Huibert MD
Albert Schweitzer Hospital, Dordrecht, the Netherlands
Department: Intensive Care
Rasmussen, Bodil Steen
Professor, MD, PhD
Department of Anaesthesia and Intensive Care Medicine
Aalborg University Hospital
Sander, Michael
Department of Anaesthesiology, Intensive Care Medicine and Pain Therapy
University Hospital Gießen and Marburg GmbH
Justus-Liebig-Universität Gießen
Schuerer, Douglas MD, FACS, FCCM
Washington University School of Medicine
Department of Surgery, St. Louis, MO
Smetana, Gerald W. M.D.
Division of General Medicine and Primary Care
Beth Israel Deaconess Medical Center, Boston
Professor of Medicine
Harvard Medical School
Summers, Charlotte BSc BM PhD MRCP FFICM
University Lecturer in Intensive Care Medicine
Division of Anaesthesia
University of Cambridge School of Clinical Medicine
Addenbrooke’s Hospital
Talmor, Daniel MD, MPH
Department of Anesthesia, Critical Care, and Pain Medicine
Beth Israel Deaconess Medical Center and Harvard Medical School
Valkenet, Karin
UMC Utrecht in Action and Coördinating researcher PREPARE study, Dep. Rehabilitation, Nursing Science & Sport, University Medical Center Utrecht, The Netherlands
Veličković, Jelena MD
Clinical Centre of Serbia, Belgrade, Serbia
University of Belgrade, School of Medicine
Vincent, Jean-Louis
Professor of Intensive Care Medicine (Université Libre de Bruxelles)
Dept of Intensive Care, Erasme Univ Hospital
President, World Federation of Societies of Intensive and Critical Care Medicine (WFSICCM)
Wren, Sherry M. MD, FACS
Professor of Surgery
Stanford University School of Medicine