• Users Online: 3509
  • Print this page
  • Email this page

 Table of Contents    
Year : 2011  |  Volume : 55  |  Issue : 1  |  Page : 10-11  

Negative pressure pulmonary oedema

Department of Anaesthesiology, Command Hospital (CC), Lucknow, Uttar Pradesh, India

Date of Web Publication9-Feb-2011

Correspondence Address:
Mukul C Kapoor
Department of Anaesthesiology, Command Hospital (CC), Lucknow, Uttar Pradesh
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0019-5049.76566

Rights and Permissions

How to cite this article:
Kapoor MC. Negative pressure pulmonary oedema. Indian J Anaesth 2011;55:10-1

How to cite this URL:
Kapoor MC. Negative pressure pulmonary oedema. Indian J Anaesth [serial online] 2011 [cited 2021 Jul 26];55:10-1. Available from: https://www.ijaweb.org/text.asp?2011/55/1/10/76566

Pulmonary oedema is defined as abnormal accumulation of fluid in the extravascular compartment of the lung. Negative pressure pulmonary oedema (NPPO) represents a pure form of hydrostatic oedema. [1] NPPO has also been referred to as 'post-obstructive pulmonary oedema' and 'laryngospasm-induced pulmonary oedema'. It characteristically occurs after relief of upper airway obstruction, generally from laryngospasm. Other reported causes of NPPO are impacted foreign body trachea/bronchus, epiglottitis, strangulation, vocal cord palsy, acromegaly, goitre, inspissated tracheal secretions, direct suctioning of the endotracheal tube adapter, hiccoughs, croup,temporomandibular joint arthroscopy, difficult intubation, haematoma, upper airway tumour, oropharyngeal surgery, Ludwig angina, obesity, obstructive sleep apnoea, mediastinal tumour, biting/obstruction of the endotracheal tube/laryngeal mask and falling back of tongue. [1],[2]

The incidence of NPPO, as a complication of all anaesthetics, is said to be 0.05-0.1%. [2] It has however been suggested that the occurrence of NPPO is under-reported, as it is often unrecognized or misdiagnosed.[2] The morbidity and mortality of an un-recognized event of NPPO is as high as 40%. [3] Patients are usually young, athletic males capable of generating profound negative intra-thoracic pressure (ITP). [4] (Healthy human subjects can generate negative ITP to a reported maximum of -140 cm H 2 O.) [5]

In case the obstruction is primarily during inspiration, the patient tries to overcome the obstruction with a forced inhalation effort (Muller manoeuvre). This results in development of high negative ITP and a rise in venous return, which induces hydrostatic transudation of fluid into the extra-vascular compartment. In case there is obstruction during both inspiration and expiration, high positive ITP prevents the development of oedema. However, oedema develops on relief of the obstruction due to a sudden fall in the ITP. [6] It has been suggested that the aetiology of pulmonary oedema represents an interplay between several factors, which include cardiogenic and neurogenic mechanisms, as well as hypoxia. [7]

Although negative ITP is the primary pathological event in the genesis of NPPO, hypoxia, hypercarbia, acidosis, and hyperadrenergic state contribute to its development. Increased right heart filling, decreased left heart filling, increased left ventricular afterload and decreased LV ejection lead to increased pulmonary capillary hydrostatic pressure. [8] Hypoxaemia increases pulmonary vascular resistance resulting in a rise in pulmonary capillary wedge pressure. Hypoxaemia alters the capillary integrity and precipitates a hyperadrenergic status. This along with the hypercarbia, redistributes blood from the systemic circulation to the pulmonary circulation. Hypoxaemia and acidaemia have myocardial depressant effects, which also contributes to pulmonary oedema formation. [9],[10] Another potential cause cited is capillary leak due to capillary disruption from shear stretching forces of high ITP or extreme hypoxia. [11] However, a recent study has established that hydrostatic forces are the primary mechanism behind NPPO and that the alveolar epithelium remains functionally intact in acute NPPO. [1] The combination of increased preload and afterload leads to a marked rise in hydrostatic pressure in the pulmonary microvasculature, and, as dictated by the Starling equation, fluid filters out of the microcirculation into the lung interstitium. [1]

The most common clinical presentation of NPPO is the occurrence of airway obstruction on emergence from general anaesthesia, followed by the rapid onset of respiratory distress, haemoptysis and clinical/radiological features consistent with bilateral pulmonary oedema. Typically, NPPO radiologically manifests as Kerley lines, peribronchial cuffing and, in severe cases, as central alveolar oedema. Cardiac size is usually normal as hypervolaemia is not present. [6] Resolution of the clinical and radiological features is rapid, usually within 24 h.

Radiologically, the two patho-physiological phases in the development of pressure oedema are interstitial oedema and alveolar flooding. Interstitial oedema occurs with a rise in transmural arterial pressure of 15-25 mmHg and is characterized by the appearance of peribronchial cuffing, Kerley lines and subpleural effusion. With increases in transmural pressure to greater than 25 mmHg, there is extension of oedema into alveolar spaces, creating nodular areas of opacity that coalesce into frank consolidations. [6]

Differential diagnoses of NPPO include aspiration pneumonitis, acute lung injury, cardiogenic pulmonary oedema, fluid overload, drug-induced non-cardiogenic pulmonary oedema and anaphylaxis. Treatment modalities range from oxygen supplementation through mask, to mask CPAP, tracheal intubation and positive pressure ventilation. Some cases require minimal supportive care, including maintenance of a patent airway and administration of supplemental oxygen; however, most of the patients require reintubation and ventilation with positive airway pressure. [4] It is important to apply positive pressure to the airway early. Nasal bi-level positive airway pressure, mask CPAP and intubation and ventilation with PEEP have been used successfully. [2] Diuretics are often administered but their role is uncertain. [4] Early relief of laryngospasm with neuromuscular blockers has been suggested to "break" the laryngospasm and put a stop to the sustained negative ITP, hyperadrenergic drive and hypoxia implicated in the pathogenesis of NPPO. [2]

   References Top

1.Fremont RD, Kallet RH, Matthay MA, Ware LB. Postobstructive pulmonary edema: A case for hydrostatic mechanisms. Chest 2007;131:1742-6.  Back to cited text no. 1
2.McConkey PP. Post obstructive pulmonary oedema: A case series and review. Anaesth Intensive Care 2000;28:72-6.  Back to cited text no. 2
3.Goldenberg JD, Portugal LG, Wenig BL, Weingarten RT. Negative pressure pulmonary edema in the otolaryngology patient. Otolaryngol Head Neck Surg 1997;117:62-6.  Back to cited text no. 3
4.Deepika K, Kenaan CA, Barrocas AM, Fonseca JJ, Bikazi GB. Negative pressure pulmonary edema after acute upper airway obstruction. J Clin Anesth 1997;9:403-8.  Back to cited text no. 4
5.Cook CD, Mead J. Maximum and minimum airway pressures at various lung volumes in normal children and adults. Fed Proc 1960;19:377.  Back to cited text no. 5
6.Gluecker T, Capasso P, Schnyder P, Gudinchet F, Schaller MD, Revelly JP, et al. Clinical and radiologic features of pulmonary edema. Radiographics 1999;19:1507-31.  Back to cited text no. 6
7.Holmes JR, Hensinger RN, Wojtys EW. Postoperative pulmonary edema in young, athletic adults. Am J Sports Med 1991;19:365-71.  Back to cited text no. 7
8.Rowbotham JL, Scharf SM. Effects of positive and negative pressure ventilation on cardiac performance. Clin Chest Med 1983;4:161-83.  Back to cited text no. 8
9.Lorch DG, Sahn SA. Post extubation pulmonary edema following anesthesia induced by upper airway obstruction. Chest 1986;90:802-5.  Back to cited text no. 9
10.Koch SM, Abramson DC, Ford M, Peterson D, Katz J. Bronchoscopic findings in postobstructive pulmonary oedema. Can J Anaesth 1996;43:73-6.  Back to cited text no. 10
11.Kallet RH, Daniel BM, Gropper M, Matthay MA. Acute pulmonary edema following upper airway obstruction: Case reports and brief review. Respir Care 1998;43:476-80.  Back to cited text no. 11

This article has been cited by
1 Recurrent negative pressure pulmonary oedema after tracheal extubation
Shalendra Singh,Monish Nakra,Anand Shankar K,Mathews Jacob
Medical Journal Armed Forces India. 2012;
[Pubmed] | [DOI]


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

  In this article

 Article Access Statistics
    PDF Downloaded2594    
    Comments [Add]    
    Cited by others 1    

Recommend this journal