nppe is an uncommon complication of extubation in the early post - operative period and most commonly caused by laryngospasm .
acute laryngeal spasm results in airway obstruction and can cause life threatening pulmonary edema due to negative intra thoracic pressure .
the incidence of nppe has been reported to be 0.05 to 0.1% of all anesthesiology practices however it may be underreported due to failure of recognizing or misdiagnosing .
a 37-year - old male patient was referred to the emergency department due to developing of severe chest pain , hypotension , and dyspnea following septoplasty operation . on admission ,
physical examination revealed blood pressure of 70/40 mmhg , heart rate of 75/min , bilateral diffuse crackles at the lung and wheezy breathing .
oxygen saturation was 60 - 70% while breathing high - flow oxygen through a face mask .
twelve - lead resting electrocardiography ( ecg ) revealed deep and down - sloping st - segment depressions of 3 mm in the precordial leads [ figure 1 ] .
due to elevated cardiac biomarkers on admission ( troponin i level : 2,1 ng / dl and creatine kinase myocardial band ( ck - mb ) level : 7,4 mg / dl ) he immediately underwent cardiac catheterization with the diagnosis of non - st elevation myocardial infarction , acute pulmonary edema and cardiogenic shock .
twelve - lead resting electrocardiography showing deep and down - sloping st segment depressions in the precordial leads bedside transthoracic echocardiography showed .
ejection fraction was normal , estimated pulmonary arterial pressure was not elevated and there was no evidence of thrombus in the main pulmonary artery .
there was only increase in diffuse density of the lungs supporting congestion : [ figure 2 ] .
thoracic computerized tomography angiography demonstrating increase in diffuse density of the lungs supporting acute diagnosis acute pulmonary edema after coronary angiography , the patient was followed in the intensive care unit . during the follow - up , his oxygen saturation and blood pressure levels
were increased , chest pain , and dyspnea were improved with high - flow oxygen , inotropic support , and diuretics .
based on these laboratory parameters , imaging results and clinical course , the patient was diagnosed as hypoxia - induced acute subendocardial myocardial infarction , which is an unexpected result of negative pressure pulmonary edema .
nppe is one of the causes of non - cardiogenic pulmonary edema which occurs with increased inspiration effort and upper respiratory tract obstruction following upper respiratory , oropharyngeal , and nasal surgeries .
nppe , usually occurs during emergence from general anesthesia in the early post - operative period especially after upper respiratory tract surgery and may less frequently occur in various clinical situations ( electroconvulsive therapy , etc . ) .
upper respiratory tract obstruction caused by laryngospasm which occurs especially after extubation has been suggested as the most common cause of the nppe . increased inspiration effort caused by upper respiratory tract obstruction elevates the negative intrathoracic pressure and this condition progresses to the nppe .
there are some investigations which reports healthy , young , and well - built adults are more prone to nppe because of their ability to further increase the negative intrathoracic pressure .
an entirely different population carries high nppe risk which consist of the patients who are obese and patients who have obstructive sleep apnea syndrome , mediastinal mass , and upper respiratory tract obstruction . depending on the clinical circumstance ,
if diagnosed early , many patients do not need aggressive therapies but some patients will need invasive or non - invasive mechanical ventilation . patients usually respond to well fluid restriction , diuretics and corticosteroids . to the best of our knowledge ,
the diagnosis of nppe was missed in the early post - operative period , and therefore , the clinical status of the patient deteriorated with time .
the complains of chest pain and dyspnea were misdiagnosed as acute coronary syndrome , acute pulmonary edema and hypotensive shock in the emergency service . in conclusion ,
other than anesthesiologists , the cardiologists , pulmonologists , and emergency physicians must be aware of the nppe , a diagnosis of exclusion , in the differential diagnosis of acute pulmonary edema .
 negative pressure pulmonary edema ( nppe ) is defined as fluid transudation into the pulmonary interstitium which occurs as a result of elevated negative intrathoracic pressure caused by the upper respiratory tract obstruction and strong inspiratory effort . 
 nppe is usually seen during emergence from general anesthesia in the early post - operative period especially after upper respiratory tract surgery . 
 we present a case of a 37-year - old male patient who underwent septoplasty operation and developed nppe which could not diagnosed and progressed to acute subendocardial myocardial infarction . 
INTRODUCTION
CASE REPORT
DISCUSSION