Clinical:
Pulmonary embolism (PE) is a common and potentially lethal condition that can cause death in all age groups. A good clinician should consider the diagnosis if any suspicion of pulmonary embolism exists, because prompt diagnosis and treatment can dramatically reduce the morbidity and mortality of the disease. Unfortunately, the diagnosis is often missed, because pulmonary embolism frequently causes only vague and nonspecific symptoms.
The variability of presentation sets the patient and clinician up for potentially missing the diagnosis. The challenge is that the "classic" presentation with abrupt onset of pleuritic chest pain, shortness of breath, and hypoxia is rarely the case. Studies of patients who die unexpectedly of pulmonary embolism reveal that they complained of nagging symptoms often for weeks before death related to pulmonary embolism. Forty percent of these patients had been seen by a physician in the weeks prior to their death.
Symtoms that could order to a suspicion PE include:
History:
- The classic triad symtoms are hemoptysis, dyspnea, chest pain. But they are not specific.
- Pleuritic chest pain: the “classic” symtom often exist with frequency 88%, sometimes it is vague with back pain, shoulder pain, upper abdominal pain,
- Dypsnea
- Cough
- Panic, fear
- Sweat
- Swoon
Physical:
- Tachypea : more than 25 /m
- Rales
- accentuated second heart sound
- tachycardia: more than 100 /m
- T 3 or T4 gallop
- Cyanosis
- clinical signs and symptoms suggesting thrombophlebitis

However, diagnosis is usually based on subclinical, because the clinical is nonspecific and easily to have a míâtake in diagnosis with other disease
Laboratory Studies:
- The white blood cell (WBC) count may be normal or elevated. A WBC count as high as 20,000 is not uncommon in patients with PE
- The PO2 on arterial blood gases analysis (ABG) has a zero or even negative predictive value in a typical population of patients in whom PE is suspected clinically. This is contrary to what has been taught in many textbooks, and it seems counterintuitive, but it is demonstrably true
- D-dimer is a unique degradation product produced by plasmin-mediated proteolysis of cross-linked fibrin. D-dimer is measured by latex agglutination or by an enzyme-linked immunosorbent assay (ELISA) and a test result is considered positive if the level is greater than 500 ng/mL.
Imaging Studies
- initial chest radiographic: they may show the Westermark sign (ie, a dilatation of the pulmonary vessels proximal to an embolism along with collapse of distal vessels, sometimes with a sharp cutoff).
- Vascular ultrarsound: deep vein thrombosis
- Helical CT:
- ventilation-perfusion (V/Q) scanning
- Electrocardiography
o The most common ECG abnormalities in the setting of pulmonary embolism (PE) are tachycardia and nonspecific ST-T wave abnormalities. The finding of S 1 Q 3 T 3 is nonspecific and insensitive in the absence of clinical suspicion for PE.

discreminate tachypnea and hyperventilation

Tachypnea: (Pronounced tack-ip-nea.) Abnormally fast breathing. A respiratory rate that is too rapid. The normal rate of respirations (breaths per minute) depends on a number of factors, including the age of the individual and the degree of exertion.
The prefix tachy- means swift or rapid; it comes from the Greek word tachys, meaning "swift." The word ending -pnea denotes a relationship to breathing; it comes from the Greek pnoia, meaning breath.
Hyperventilation Hyperventilation is rapid or deep breathing that can occur with anxiety or panic. It is also called overbreathing, and may leave you feeling breathless.
When you breathe, you inhale oxygen and exhale carbon dioxide. Excessive breathing leads to low levels of carbon dioxide in your blood. This causes many of the symptoms you may feel if you hyperventilate.
Feeling very anxious or having a panic attack are the usual reasons that you may hyperventilate