ICU · Respiratory / ventilation
Auto-PEEP & Ventilation in Obstruction (Asthma & COPD)
Also known as Auto-PEEP · Intrinsic PEEP · Dynamic hyperinflation · Permissive hypercapnia · Ventilation in asthma · Ventilation in COPD · Status asthmaticus ventilation · Inspiratory threshold load · Breath stacking
In severe airflow obstruction (asthma, COPD), incomplete expiration traps gas and generates intrinsic (auto-) PEEP and dynamic hyperinflation, which raise the work of breathing, depress venous return and cardiac output, and risk barotrauma. Ventilation must prioritise emptying over ventilation: controlled (permissive) hypercapnia that corrects hypoxaemia while accepting hypercapnia, a low tidal volume, a low respiratory rate for a long expiratory time, a high inspiratory flow, and external PEEP kept below the measured intrinsic PEEP. If the blood pressure crashes after intubation, disconnect the circuit to let the lung deflate.
Practise this topic
On this page
Study tools
Your progress
Saved on this device.
Target exams
Definition — what auto-PEEP actually is
Auto-PEEP is occult positive end-expiratory pressure — a positive alveolar pressure at end-expiration that the ventilator cannot see because it is trapped behind obstructed or collapsed airways. In severe asthma and COPD the patient cannot fully exhale before the next breath arrives, gas accumulates, the lungs hyperinflate, and intrathoracic pressure rises. The paradigm shift: the goal of mechanical ventilation here is to empty the lung, not to normalise the CO2.[1][2][3]
References12ShowHide
- [1]Laher AE, Buchanan SK. Mechanically Ventilating the Severe Asthmatic J Intensive Care Med, 2018.PMID 29105540
- [2]Pepe PE, Marini JJ. Occult positive end-expiratory pressure in mechanically ventilated patients with airflow obstruction: the auto-PEEP effect Am Rev Respir Dis, 1982.PMID 7046541
- [3]Darioli R, Perret C. Mechanical controlled hypoventilation in status asthmaticus Am Rev Respir Dis, 1984.PMID 6703497
- [4]Williams TJ, Tuxen DV, Scheinkestel CD, et al. Risk factors for morbidity in mechanically ventilated patients with acute severe asthma Am Rev Respir Dis, 1992.PMID 1519836
- [5]Appendini L, Purro A, Patessio A, et al. Partitioning of inspiratory muscle workload and pressure assistance in ventilator-dependent COPD patients Am J Respir Crit Care Med, 1996.PMID 8912740
- [6]Ranieri VM, Dambrosio M, Brienza N Intrinsic PEEP and cardiopulmonary interaction in patients with COPD and acute ventilatory failure Eur Respir J, 1996.PMID 8804950
- [7]Blanch L, Bernabé F, Lucangelo U Measurement of air trapping, intrinsic positive end-expiratory pressure, and dynamic hyperinflation in mechanically ventilated patients Respir Care, 2005.PMID 15636649
- [8]Mosier JM, Hypes CD Mechanical Ventilation Strategies for the Patient with Severe Obstructive Lung Disease Emerg Med Clin North Am, 2019.PMID 31262414
- [9]Leatherman JW. Mechanical ventilation for severe asthma Chest, 2015.PMID 26033128
- [10]Reddy VG. Auto-PEEP: how to detect and how to prevent--a review Middle East J Anaesthesiol, 2005.PMID 16438005
- [11]Silverman R, Osborn H, Runge J, et al. IV magnesium sulfate in the treatment of acute severe asthma: a multicenter randomized controlled trial Chest, 2002.PMID 12171821
- [12]Schneider W, Lewis L, Ferguson N, et al. Repeated dyspnea score and percent FEV1 are modest predictors of hospitalization/relapse in patients with acute asthma exacerbation Respir Med, 2014.PMID 25087835