Pulmonary embolism (PE) can be detected and investigated through several tests: Pulse oximetry monitors for hypoxemia and oxygen supplementation is initiated, while further tests are done. Electrocardiograms can show changes indicating conditions like pulmonary embolism or right heart strain. Arterial blood gases may demonstrate hypoxemia, hypocapnia, or acidosis in PE. Chest x-rays can reveal signs of PE like enlarged heart size or perfusion deficits on lung scans. D-dimer tests if elevated suggest a thrombus, while normal levels rule out recent clots. CT pulmonary angiograms are best to diagnose or rule out PE due to speed, availability and ability to detect other lung abnormalities

1. PULMONARY EMBOLISM
DETECTION
Fatima Al Awadh

2. EMERGENCY INVESTIGATIONS
Pulse Oximetry
ElectroCardioGram.
Arterial Blood Gases.
Complete Blood Count.
Cardiac Enzymes.
Chest Radiograph.

3. PULSE OXIMETRY
detection and
ongoing monitoring
of hypoxaemia with
initiation of oxygen
supplementation as
necessary, while
undertaking
diagnostic work-up
for its cause.

4. ELECTROCARDIOGRAM
Acute coronary syndromes ST-T-segment changes.
Pericarditis, cardiac tamponade low voltage.
Pulmonary embolism tachycardia.
Right atrial enlargement p-wave changes
Change in the QRS right (COPD, pulmonary
hypertension) or left (hypertension, valvular heart
disease).

5. ARTERIAL BLOOD GASES
Hypercapnia exacerbation of COPD, stroke, or upper airway
obstruction.
Hypocapnia anxiety and hyperventilation, as in pulmonary
embolism.
Hypoxaemia ARDS, pneumonia, COPD, asthma, pulmonary
embolism, interstitial lung disease, stroke, or upper airway
obstruction.
Acidosis sepsis, pulmonary oedema, exacerbation of COPD
Alkalosis anxiety, dehydration, or pulmonary embolism.

6. COMPLETE BLOOD COUNT
Leukocytosis infectious process, autoimmune disease,
and leukemia.
Eosinophilia parasitic disease, certain vasculitides (e.g.,
Churg-Strauss syndrome), asthma, eosinophilic pneumonia, or
cocaine.
Anaemia the primary reason for dyspnoea
or may accompany it in drug-related lung
injury, acute chest syndrome of sickle cell disease, pulmonary
alveolar haemorrhage, or widespread infectious processes.
Thrombocytopenia viral infections, including influenza,
SARS, and Hantavirus pulmonary syndrome.

7. CARDIAC ENZYMES
Acute myocardial infarction
Myocarditis
Takotsubo cardiomyopathy
or Hypothyroidism.
Troponin I/T, Myoglobin, and CK-MB

8. CHEST RADIOGRAPH
Pulmonary venous congestion and an enlarged heart
CHF.
Parenchymal infiltrates infectious pneumonia, or
pulmonary oedema.
Pleural effusion CHF, liver failure, pulmonary embolism,
or pleuritis.
Lung hyperinflation COPD, exacerbation of asthma, or
foreign body aspiration.
Unilateral lucidity pneumothorax or a diaphragmatic
hernia.
Prominent hilar vessels pulmonary hypertension.

9. SPECIFIC INVESTIGATIONS FOR PE
CT angiography of the chest

10. D-DIMER
a by-product of intrinsic fibrinolysis.
elevated levels occur in the presence of a recent
thrombus.
not specific for venous thrombus.
absence of elevated levels suggests the absence
of recent thrombus because the test is sensitive.

11. V/Q SCANS
detect areas of lung that are ventilated but not perfused,
as occurs in PE
results are reported as low, intermediate, or high
probability of PE based on patterns of V/Q mismatch
completely normal scan excludes PE with nearly 100%
accuracy
Perfusion deficits may occur in many other lung
conditions, including pleural effusion, chest mass,
pulmonary hypertension, pneumonia, and COPD.

12. ABNORMAL PERFUSION
SCAN
Showing multiple peripheral perfusion defects in both lungs. In the pre

13. NORMAL VENTILATION SCAN
This "mismatch" between abnormal perfusion and normal
ventilation of the right lung indicates a high probability of acute
pulmonary embolism.

14. CT ANGIOGRAPHY OF THE CHEST
The best investigation for diagnosing and excluding pulmonary
embolism.
Fast, available, and noninvasive.
Also detect pulmonary parenchymal disease, pulmonary oedema,
airway and vascular abnormalities, pleural effusion.
The sensitivity is highest in lobar and segmental vessels and lowest
for emboli sub-segmental vessels and thus is less sensitive than
perfusion scans.
Sensitivities range from 53 to 100%; Specificities range from 81 to
100%.

16. REFERENCES
Merck Manuals.
Gyton Medical Physiology.
WALTER C. MORGAN, HEIDI L. HODGE, Diagnostic Evaluation of Dyspnea. Am
Fam Physician. 1998 Feb 15;57(4):711-716.
Conrad Wittram, Michael M. Maher, Albert J. Yoo, Mannudeep K. Kalra, , Jo-Anne
O. Shepard, and, Theresa C. McLoud, CT Angiography of Pulmonary Embolism:
Diagnostic Criteria and Causes of Misdiagnosis September 2004 Volume 24, Issue
5.
WWW.BestPractise.bmj.com

17. “Thank You”