Mechanical Insufflation-Exsufflation in the Intensive Care Unit - a case report series
Issue Name: Phys Resp Care Volume 1 (1)
Issue Date: 30 July 2026
Article Location: p2-10
Ema Swingwood Thomas Lunn Rosie O'Reilly
DOI: https://doi.org/10.56792/MDDF8177
Lead Author: Ema Swingwood ema.swingwood@uhbw.nhs.uk
Introduction
Effective airway clearance is a common challenge in the intensive care unit (ICU). The cough mechanism can be impaired due to the presence of an artificial airway, respiratory muscle weakness, prolonged inactivity and altered mucociliary clearance,1–4 increasing the risk of ventilator acquired pneumonia, extubation failure and increased length of stay and mortality.5,6
Mechanical Insufflation-Exsufflation (MI-E) is an emerging airway clearance technique used in the ICU. MI-E can be applied non-invasively, and through an artificial airway to augment expiratory flow through the delivery of rapidly alternating positive (insufflation) and negative (exsufflation) pressures to simulate a cough and aid secretion clearance.4,7,8 MI-E is recommended as a minimum standard of physiotherapy clinical practice in UK ICU’s9 and has a growing evidence base from in vivo and in vitro studies for use in the critically ill, intubated population.10 However, barriers to device implementation remain with safety concerns highlighted related to factors including high positive end expiratory pressure (PEEP) levels, risk of cardiovascular instability, lung protection and risk of pneumothoraces.10,11
The ICU hosts a highly heterogeneous patient population with varying conditions, age, comorbidities and severity of illness. This diversity presents a unique challenge for assessment, treatment and monitoring. Our case studies look to build on the current evidence base and provide clinical reasoning to illustrate the use of MI-E in less commonly described patient cases.
Method
This case series follows the CARE case report guidelines and describes the application and associated clinical reasoning for MI-E use in ICU patients. A brief patient presentation and description of the MI-E intervention will be provided for each case. This will conclude with a discussion of the implications for clinical practice with reference to the current evidence base.
Informed consent was gained from the patients or next of kin for data to be published. This case series report was deemed not to require ethical approval.12
The cases took place in an acute teaching hospital in a general intensive care unit, where MI-E forms part of usual care. MI-E is therefore a familiar treatment intervention to both the physiotherapy team and the wider multi-disciplinary team (MDT). Physiotherapists involved in the delivery of the patient contacts described ranged from Agenda for Change bandings 6-8. For clarity, adverse events were considered as anything resulting in treatment cessation or requiring medical intervention. Additionally, authors considered the ongoing clinical course of each patient to ensure any adverse events had occurred following the physiotherapy intervention, for example the development of a pneumothorax.
Case Study 1: MI-E in the deceased organ donation patient
Patient description
A 26-year-old female was admitted to ICU following an epileptic seizure leading to respiratory arrest. Imaging and ancillary testing demonstrated brain stem death and consent for organ donation was granted.
At this time, indications for physiotherapy included volume loss and absent cough, leading to retained tenacious secretions, saw-toothing on expiratory flow curve and ventilation-perfusion mismatch demonstrated by rising FiO2 requirements and hepatised lung tissue noted on lung ultrasound (Figure 1).
Therapeutic intervention
Physiotherapy treatment included MI-E, manual expiratory vibrations, saline instillation and suctioning. Manual expiratory vibrations were used to increase expiratory flow bias, thus further augmenting cough. MI-E (insufflation:exsufflation pressures of +30:-40cmH20) with a ratio of insufflation to exsufflation of 5:1 to optimise re-recruitment post exsufflation. Ten re-recruitment insufflations were utilised prior to return to ventilation.
Twice daily treatment was provided to maintain good oxygenation to body organs for donation. Table 1 demonstrates pre and post treatment ventilatory parameters after the first session of MI-E. To ensure lung viability (PO2 >40 kPa or >300mmHg on FiO2 1.0 and PEEP 5 testing,13,14 the frequency of MI-E use increased in response to dropping PaO2 in the 24 hours prior to organ retrieval (Figure 2).
Treatment outcomes
A high volume of secretions was cleared during each MI-E intervention. There were no adverse events associated to the use of MI-E. Six organs were successfully retrieved for transplant from this patient, in part due to optimised pulmonary gas exchange.
Case Study 2: MI-E in a patient requiring veno-venous extra-corporeal membrane oxygenation (VV-ECMO)
Patient description
A 33-year-old male receiving VV-ECMO treatment for aspiration pneumonia following failure to improve with conventional invasive mechanical ventilation and proning. This case relates to day nine post initiation of VV-ECMO. ECMO settings included a sweep gas flow of 6.5 L/min and a blood flow of 3.4 L/min, with no concerns about the ECMO circuit.
The patient was ventilated on PC-BiPAP (Table 2) with sedation and paralysing agents being utilised to maintain good ventilation and ensure lower demand upon VV-ECMO circuit. Cardiovascular stability was optimised with minimal requirement of noradrenaline (0.01 mcg/kg/hr). A computerised tomography (CT) scan from 2 days prior demonstrated good aeration in upper and middle lobes with subtle residual airspace opacities. Moderate bilateral pleural effusions were present, with collapse and consolidation of the lower lobes, complete on the right, and almost complete on the left.
At the time of physiotherapy assessment, small quantities of secretions were being cleared by the nursing team, with no cough present secondary to paralysing agents. Indications for physiotherapy intervention included reduced lung volumes and retained secretions.
Therapeutic intervention
The MI-E device was initiated with the aim of increasing lung volume and augmentation of cough. MI-E (insufflation:exsufflation pressures of +30:-35cmH20, 4:1) was completed in alternate side lying (10 cycles left and 8 cycles right) with oxygen entrained at 15 L/min. Manual expiratory vibrations were utilised to further increase expiratory flow bias. Ten re-recruitment insufflations were utilised prior to return to ventilation.
Treatment outcome
No adverse events were noted during the MI-E intervention. Furthermore, blood pressure remained stable with no interruption of ECMO blood flow.
Copious purulent secretions were cleared, resulting in an increase in lung volumes, and associated improvements in airway resistance and dynamic lung compliance (Table 2). Figure 3 illustrates chest X-Rays changes from the day prior, and the day post MI-E intervention. As a result of increasing tidal volume (TV) and the resulting improvement in native lung CO2 clearance, ECMO sweep gas flow was weaned.
Case Study 3: MI-E in a patient with rib fractures
Patient description
This case describes the treatment of a 71-year-old, morbidly obese male who had sustained substantial rib injury by falling from a concrete wall. Injuries included left fractures laterally and anteriorly to ribs 3-9; posterior fractures to ribs 5, 8-10 with confirmed flail segments at rib 8 and 9.
At day 3 post injury the patient went to theatre for surgical rib fixation of the flail segment with drainage of a haemopneumothorax and insertion of a left sided chest drain.
Physiotherapy assessment occurred day one post operatively. At this time point the patient remained intubated and ventilated via an endotracheal tube. Key problems included ongoing pain (limiting increases to tidal volumes and cough effectiveness), evidence of retained tenacious secretions on auscultation, and hypoxia with an ongoing oxygen requirement.
Therapeutic intervention
Initial physiotherapy treatment included ventilator hyperinflation in alternate side lie with saline and suction. The patient was reliant on oxygen boluses for suctioning to prevent desaturation.
MI-E (insufflation:exsufflation pressures of +25:-35cmH20, 4:1, 3 cycles per side with 8 L/min oxygen entrained) was instigated on day 4 prior to extubation with the aim of further optimising secretion clearance and promoting extubation success. Table 3 illustrates an overview of assessment findings. The patient was extubated onto CPAP later that day.
Day one post extubation, the patient was on high flow nasal cannulae (FiO2 0.30, flow 35L/min) due to poor CPAP tolerance overnight. Assessment illustrated ongoing retained secretions due to poor cough effectiveness despite pain relief being in situ. MI-E was completed as per previous settings. Six cycles were completed in total in alternate side lying.
Treatment outcome
The patient was successfully extubated. MI-E optimised secretion clearance and augmented lung volumes illustrated through repeated auscultation, thus preventing the need for reintubation. Regular use of the device was tolerated from a pain perspective and oxygen requirements were reduced over the course of MI-E treatment. No adverse effects associated to MI-E use were reported when used with both an ETT and facemask.
Discussion
This paper describes the use of MI-E in the intubated, critically ill population, where application was consistently indicated due to absent or ineffective cough. Despite evidence promoting the use of MI-E in this patient group, barriers to widespread implementation remain.10,11 Two prominent considerations were identified in the case studies discussed: concerns regarding safety and a lack of guidance for targeted clinical application.
Patient safety
Ventilation strategies in ICU often focus on lung protection or rest, especially in the management of a patient on ECMO. When using MI-E it is therefore key to consider the high positives pressures that are used to recruit lung prior to cough augmentation. This is particularly important when large portions of the lung are either inflamed or consolidated, an issue termed as “baby lung”.15
In the ECMO case study, CT scans were analysed and showed minimal inflammation but with consolidated and collapsed lung. This was deemed potentially amenable to recruitment, following secretion clearance, with minimal risk of causing an increase in the inflammatory process. The use of positive pressure requires careful consideration due to the significant power (high pressures and rates) it can create. This power can increase lung inflammation16,17 and increased risk of pneumothorax18 if not considered.
Research to date has suggested the need for higher insufflation pressures (>40cmH2O) when using MI-E via an artificial airway to generate sufficient expiratory flow greater than 2.7L/second to facilitate secretion clearance.18,19 All presented cases demonstrated adequate clearance achieved with lower insufflation pressure delivery (+25-30cmH2O). This is potentially a useful finding; lower MI-E insufflation pressures may reduce the risk of lung injury through barotrauma and volutrauma. Furthermore, the use of lower pressures with positive patient outcomes may eliminate clinician concern regarding safety which is a current barrier to device use in this population. The impact of MI-E delivery on resultant lung recruitment and de-recruitment is a current gap in the evidence base. Oxygen entrainment may supplement oxygenation or reduce possible desaturation risk. During ECMO, support can be maintained via higher blood flow or, as in this case, respiratory entrainment. This is appropriate only in patients with sufficient ventilation–perfusion matching. The evidence base for airway clearance in the ECMO cohort remains particularly sparse. Effective airway clearance faces unique challenges associated to reduced resting (protective) tidal volumes and associated reduced flow rates.20 A recent publication21 details the use of MI-E specifically in a patient receiving ECMO support with promising patient outcomes, whilst also using lower MI-E settings. However, as a single patient case study, this remains an under-investigated area.
Clinical caution is advised when considering MI-E in patients with relative contraindications such as rib fractures or elevated PEEP. The presence of rib fractures can be very challenging for physiotherapists as many traditional hands-on airway clearance techniques such as expiratory vibrations and manual assisted coughs are not appropriate due to risk that these techniques pose to the site of rib fractures. There is currently no evidence for or against the use of MI-E in patients with rib fractures with or without flail segments. A recent delphi study however noted clinician perception that MI-E can lead to pneumothorax in patients with flail or severely displaced rib fractures.22 The current patient case however, illustrated the beneficial impact of MI-E, which facilitated secretion clearance with no adverse effects. This highlights the importance of individualised risk assessment and balance of risk/benefit on a case-by-case basis.
Guidance for Targeted Clinical Application
There is no consensus on the optimal patient population for MI-E use, particularly in unique groups such as ECMO, organ donation and poly trauma.
This is particularly important in deceased organ donors where physiotherapy’s role remains unclear.23,24 While optimising ventilation to maintain organ perfusion is established24,25 the lack of standardised physiotherapy protocols presents challenges for MI-E initiation in these patients.24,26
In the deceased organ donor case, MI-E ensured viability of the donated organs through maintaining optimal perfusion to all organs, plus offering transplanted lungs with a reduced secretion burden. This pattern of results supports preliminary reports which illustrate a positive impact on donor oxygenation following MI-E use, whilst being both cost-effective and safe.27 An earlier single case study28 also presented pre and post physiotherapy treatment (including ventilator hyperinflation, ribcage compressions and MI-E) which resulted in improved PaO2/FiO2 ratios (from 245mmHg to 473mmHg) meaning the lungs were appropriate for procurement. These findings cannot be soley attributed to MI-E as other techniques were used in combination, however, findings remain a useful contribution to the evidence base. Limitations to the case study presented by Rodrigues-Gomes et al.28 include a lack of adverse event reporting and any longer-term outcomes. The current case series has acknowledged these gaps and reported as such, thus further contributing to the evidence base for MI-E use in this specific ICU population.
The authors acknowledge that this article provides limited information on the use of MI-E through the presentation of three clinical cases. Data presented is descriptive and limited to routinely collected information via patient records and so no inferences can be made. Cases are from a single centre where MI-E forms part of standard care and may therefore not be representative of wider UK practice. Furthermore, we acknowledge that the application of MI-E in the cases described has relied on specialist physiotherapists who are both familiar with the device and the patient populations described. This is particularly the case for the organ donation patient, whereby a recent UK mixed methods study found that only 27% (n=15) of respondents reported using advanced treatment techniques such as MI-E with this patient cohort, whereas more standard techniques including suctioning, manual techniques and positioning were used more frequently.24 The resultant advanced clinical reasoning in the current case has also occurred in an environment where the wider MDT is accepting and familiar with the use of MI-E in these more complex cases. Extrapolation of learning into other centres therefore may not occur with ease. Barriers to the implementation of MI-E in the ICU are documented and include the need for device training and experience to enhance knowledge and skills, alongside ICU MDT culture and device availability.11,29 Further work is required to determine how best to overcome such barriers. Despite the limitations discussed, the information presented contributes to the current evidence base for MI-E use in the critical care setting for more complex patient cases and illustrates potential benefits of device implementation.
Conclusion
The presented case studies aimed to demonstrate how MI-E can be used in a variety of patient cases where this intervention may not have been previously considered, be routinely used, or even thought to be contra-indicated. With careful consideration of risk factors and setting choices, these cases have shown positive treatment outcomes.
To help inform clinical decision-making, research using robust methodologies, such as randomised controlled trials, is required to evaluate the safety and effectiveness of MI-E within the critical care setting. In addition, the development of a practice-based guideline and associated teaching resources suitable for the MDT would support the optimal use of MI-E in this complex patient cohort.
Declaration of interest
Nil to declare.
Funding
No funding was sought for this project.
Acknowledgements
We are grateful to the patients and their families for providing consent to use their clinical cases.
