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PULMONARY EMBOLISM – INFECTIOUS BLOOD DISEASE A. S. Yadugiri, G.Aishwarya. II B.E. (BiomedicalEngineering) Dept. of Biomedical Engineering Rajalakshmi Engineering College, Thandalam, Chennai – 602105 E-mail: [email protected] [email protected] ABSTRACT The proposed paper discusses about the infectious blood diseases named as pulmonary embolism. This proposed paper mainly deals with increasing rate of blood disease in the lungs. Pulmunoary Embolism is the blockage in vein and due to circulation moves to the main artery which goes from heart to lungs. This paper fully discuses about the golden standard for diagonsis pulmonary enbolism is pulmonary angiography and treatment is caval filters. It is a deadly infectious disesase. Pulmonary angiography is used less often due to wider acceptance of CT scans, which are non-invasive. The cavalfilters treatment the filters are placed in inferior venacava below the orgin of renal vessels. It occurs in 1% of patient admited in hospital and resposible for 5% death of all hospital death. It may occur due to amniotic fluid ,placenta,air , fat, tumour and septic emboli from endo cardiatis affecting tricuspid or pulmonary valve. The treatments are anticouglation thromblitic threapy, caval filters.. KEY WORDS Blockage in vein, Main artery, Pulmonary angiography, Caval filters. 1. Introduction Pulmunoary Embolism occurs silent. It is the blockage in vein and due to circulation moves to the main artery which goes from heart to lungs. Usually this is due to embolism of a thrombus (blood clot) from the deep veins in the legs, a process termed venous thromboembolism. A small proportion is due to the embolization of air, fat , amniotic fluid placenta tumours and spectic emboli from endo carditis affecting tricuspid or pulmonary valve . The obstruction of the blood flow through the lungs and the resultant pressure on the right ventricle of the heart leads to the symptoms and signs of PE. The risk of PE is increased in various situations, such as cancer and prolonged bed rest.apparopriate therapy and mortality is decreased from 30-10% yet 100,000200,000 death occur per year in USA.diagnosis of the disease is very difficult. Clinical accuracy of the diagnosis is low. It the prospective investigations of PE study 755 patients had v/q lung scan and PE Angiography because of suspected PE within 24hrs study.. PULMONARY EMBOLISM Pulmonary embolism can be usefully consider under the heading venous thromboembolism 75%of pulmonary embolism derived from DVT in the lower limb and 60% of patient with DVT will have evidence of PE on scanning even the absence of the symptoms rarely PE may occur due to amniotic fluid, placenta, air, fat, tumour and septic emboli from endocarditis affecting tricuspid or pulmonary valves. Pulmonary emboli occur in 1% of the patients admitted in the hospital and are responsible for 5% death. He suggested 3 modes of death in PE STUDIES RELATED TO PULMONARY EMBOLISM: One of the major studies related to PE is PIOPED(Prospective investigation of pulmonary embolism). Prior to the lung scan and PE Angiography, PIOPED investigators estimated that chest x-ray , EKG, and Arteial blood gas ananlysis. The results of PIOPED makes it clear that clinical diagnosis for PE is inaccurate Accuracy of clinical diagnosis of PE in the PIOPED thus v/q lungs and PE angiography is done for diagnosis Accuarcy in clinical diagnosis of PE in PIOPED study CLINICAL NO OF PATIENTSS PROBABILITY 80-100% 90 19-79% 569 0-19% 228 Sudden(instant within ten minutes) Rapid (ten minutes to one hour) Gradual (more than one hour) HUMAN ET AL STUDIES “ The mechanism of sudden death in coronary pulmonale is unclear but it seems likely that combination of factors are involved including mechanical and humoral effects” PERCENTAGEPERCENTAGE HAVING PE CONDITIONS ASSOCIATED IN PE 10 64 26 68 30 9 Surgery 1. orthopedic 2. gynaecological cancer 3. major abdnominal 4. coronary artery 5. by pass grafting 6. renal transplantation 7. splenectomy Trauma Immobilized medical patients Cancer Pregnancy/oral contraceptives Obesity Air travel FRAMINGHAM STUDY : His study in relation with heart indicated that obesity among women is long time risk factor of PE. High degree of ancient observation that of interruption of pulmonary circulation paralyzes primarily the heart rather than respiration in turn cardiac paralyses might result from alteration of coronary blood flow. “PE is caused sudden death due to the reduced blood flow to the brain”. BARDIN STUDY He suggested that disorder under discussion might result in the sudden death through a reflex arc starting from pulmonary nerve endings,reaching vagus sympathetic or phrenic nerve fibres, the posterior cervical roots & from the respiratory & cardiac centers. LERICHE STUDY In 1947 he concluded that immediate cause of death by saying that “the patient with PE dies as well from cardiac as from respiratory causes yet also dies from cerebral causes PILCHER STUDY CLINICAL FEATURES OF PULMONARY EMBOLISM Acute massive pulmonary embolism The clinical features are of acute heamondynamic collapse with central chest pain, apprehension of low cardiac output and syncope. The phatophysiology is due to acute abstruction of more than 50% of either the main or proximal pulmonary artery, leading to an acute redction of cardiac output and right ventricular dilation. On examination there is a sinus tachycardiac , hypotention and peripheral vasoconstriction. Tachypnonea is typically present cyanosis and elevated JVP. A right ventricular gallop may be heard with wide splitting of second heart sound. Local signs. Other signs of pulmonary hypotention are not expected in acute massive pulmonary embolism. Other decreases urine output Investigation Chest radiography often subtile;oligamic lungs Field ,slight increases hilar Shadow ECG S 1Q3T3 T waves decreases Acute massive PE V1- V4 Right bundle-branch Pathophysiology major Block. heamodynamic effect Decreases the cardiac output; Acute heart failure; disorder Blood gases PaCO2 decreases PaO2;decreases V/Q scan prefusion. major area of decreases Pulmonary definite diagonsis Angiography ventilation-prefusion . ratio Cardiac arrest in acute PE Patients Symptoms sudden syncope, faintness Central chest pain, Deceased 26 Survived 2 Total 28 apprehension Sever dysponea. Episode of cardiac arrest Signs Reversible Cardiovascular 13 major circulatory collapse; Due to electromechanical dissociation 12 Due to asystole 01 Tachycardiac; hypotention; Increases jugular venous pressure Irreversible Gallop rhythm; P2 widely Due to electromechanical dissociation 22 Due to asystole 3 Due to ventricular filling after 1 split. Respiratory severe cyanosis, otherwise no Atrio ventricular block Total 39 Blood gases decreases PaCO2 V/Q scan on prefision defect not matched Acute minor pulmonary embolism The majority of patients will present with so called pulmonary infraction syndrome with pluerisy shortness of breath and haemoptysis. Clinically there may be plueral rubs and sign of a plueral effusion. The chest radiography may show wedge shaped opacity due to heamorrhages, pleural effusion or an elevated diaphragm. Some cases present with isolated breathlessness and these patients tend to have more effective central thrombus if pulmonary angiography is performed. Acute small/medium PE Pathophysiology occulusion of segmental Pulmonary artery-infraction +_effusion. the ventilation scan. Pulmonary definite diagonsis Angiography Acute embolism in patients with chronic cardio pulmonary disease Patients with a small degree of cardiopulmonary reserve may demonstrate a major sudden deterioration in their clinical state even with small pulmonary emboli. The clinical features of PE may be obscured by clinical feature of the underlying diseases and diagosis can be difficult in this important situation. A high index of suspicion is required if successful investigation and management in this group of patient are to be achived. Chronic pulmonary embolism leading to thromboembolic pulmonary hypertention. Symptoms pluerisy, restied breathing, heamophysis . Signs Cardiovascular tachycardia. Respiratory pleural rub raised Hemidiaphragm, crepiations effusion Other low grade fever This is a relatively rare but important condition which arises without a history of prevous acute PE in over 50% of cases. Patient typicaly present with a history of exertional breathlessness, syncope and chest pain developing over a months or years. On examinationther are signs of pulmonary hypertention with a loud pulmonary components to second heart sound and a right ventricular heaves. The JVP is raised and there may be v waves indicating tricuspid reguration. Patient with a pulmonary hypertention secondary to chronic pulmonary emboli should be considered for thromboendarterectomy an operation that involves removal of organised obstucting thrombus via an endarterectomy. The operation should be caried out with specalit centers despite a significant oprative mortality ,it has a high degree of success. Acute massive PE Pathophysiology Investigation Chest radiography pleuropulmonary opacities; Microvasculature, pulmonary Pleural effusion; linear shadow; Hypertention ,right heart falure. Raised hemidiaphragm ECG cornic occulision of pulmonary sinus tachycardia Symptoms RV exertional dysponea, late- Exertional syncope symptoms And RV faliure. Signs Cardiovascular disease late may be minimal early -RV heave ,loud split P2 Terminal -sign of RV faliure. Investigation Chest radiography enlarged pulmonary artery trunk Symptoms of PE are sudden-onset dyspnea (shortness of breath), tachypnea (rapid breathing), chest pain of a "pleuritic" nature (worsened by breathing), cough and hemoptysis (coughing up blood). More severe cases can include signs such as cyanosis (blue discoloration, usually of the lips and fingers), collapse, and circulatory instability. About 15% of all cases of sudden death are attributable to PE. On physical examination, a pleural rub may be audible by stethoscope over affected areas of the lung. Strain on the right ventricle may be detected as a left parasternal heave, a loud pulmonary component of the second heart sound, raised jugular venous pressure, and more rarely leg swelling. The major symptoms/ most frequent symptoms are dyspnea and pleuritic chest pain. Incidence of pleuritic pain and dyspnea in patients with angiographically documented PE Enlarged heart, prominent RV. ECG signs of RV hypertropy and strain Blood gases exertional decrease PaO2 or STUDY NO OF PATIENTS Bell.et al Dalen PIOPED 327 124 117 desaturation V/Q scan may be non abnormality. Pulmonary usually diagnotic; may need Angiography lung biopsy to confirm the Diagnosis Symptoms of pulmonary embolism include difficulty breathing, chest pain on inspiration, and palpitations. Clinical signs include low blood oxygen saturation and cyanosis, rapid breathing, and a rapid heart rate. Severe cases of PE can lead to 1. collapse, 2. abnormally low blood pressure, and 3. sudden death. Diagnosis is based on these clinical findings in combination with laboratory tests (such as the D-dimer test) and imaging studies, usually CT pulmonary angiography. Treatment is typically with anticoagulant medication, including heparin and warfarin. Severe cases may require thrombolysis with drugs such as tissue plasminogen activator (tPA) or may require surgical intervention via pulmonary thrombectomy. % WITH PLEURITIC PAIN 74 57 66 % WITH DYPSNEA 84 77 73 Diagnosis The diagnosis of PE is based primarily on validated clinical criteria combined with selective testing because the typical clinical presentation (shortness of breath, chest pain) cannot be definitively differentiated from other causes of chest pain and shortness of breath. The decision to do medical imaging is usually based on clinical grounds, i.e. the medical history, symptoms and findings on physical examination, followed by an assessment of clinical probability. The most commonly used method to predict clinical probability, the Wells score, is a clinical prediction rule, whose use is complicated by multiple versions being available. In 1995, Wells et al. initially developed a prediction rule (based on a literature search) to predict the likelihood of PE, based on clinical criteria. The prediction rule was revised in 1998 This prediction rule was further revised when simplified during a validation by Wells et al. in 2000. In the 2000 publication, Wells proposed two different scoring systems using cutoffs of 2 or 4 with the same prediction rule. In 2001, Wells published results using the more conservative cutoff of 2 to create three categories. An additional version, the "modified extended version", using the more recent cutoff of 2 but including findings from Wells's initial studies were proposed. Most recently, a further study reverted to Wells's earlier use of a cutoff of 4 points to create only two categories. There are additional prediction rules for PE, such as the Geneva rule. More importantly, the use of any rule is associated with reduction in recurrent thromboembolism. The Wells score clinically suspected DVT - 3.0 points alternative diagnosis is less likely than PE 3.0 points tachycardia - 1.5 points immobilization/surgery in previous four weeks - 1.5 points history of DVT or PE - 1.5 points hemoptysis - 1.0 points malignancy (treatment for within 6 months, palliative) - 1.0 points Traditional interpretation Score >6.0 - High (probability 59% based on pooled datal) Score 2.0 to 6.0 - Moderate (probability 29% based on pooled data) Score <2.0 - Low (probability 15% based on pooled datal) Alternate interpretation Score > 4 - PE likely. Consider diagnostic imaging. Score 4 or less - PE unlikely. Consider D-dimer to rule out PE Pulmonary angiography A pulmonary angiography is is a procedure that uses a special dye (contrast material) and x-rays to see how blood flows through the lungs. How the Test is Performed This test is done in a hospital. You will be asked to lie on an x-ray table. Electrocardiogram (ECG) leads are taped to your arms and legs to monitor the electrical impulses of the heart. Before the test starts, you will be given a mild sedative to help you relax. An area of your body, usually the arm or groin, is cleaned and numbed with a local numbing medicine (anesthetic). The radiologist makes a small surgical cut in an artery in the area that has been cleaned, and inserts a thin hollow tube called a catheter. The catheter is placed through the artery and carefully moved up into and through the heart chambers and into the pulmonary artery, which leads to the lungs. The doctor can see live x-ray images of the area on a TV-like monitor, and uses them as a guide. Once the catheter is in place, dye (contrast material) is injected into catheter. X-ray images are taken to see how the dye moves through the lung arteries. The dye helps highlight any blockages in blood flow. The catheter is occasionally flushed with saline solution containing a drug called heparin to help keep blood in the tube from clotting. Your pulse, blood pressure, and breathing are monitored during the procedure. After the x-rays are taken, the needle and catheter are withdrawn. Pressure is immediately applied to the puncture site for 10-15 minutes to stop the bleeding. After that time the area is checked and a tight bandage is applied. The leg should be kept straight for 12 hours after the procedure. The x-ray will show normal structures for the age of the patient. What Abnormal Results Mean Abnormal results may be due to: Blood clot in the lungs Narrowed blood vessel Primary pulmonary hypertension Pulmonary embolism Tumor Risks How to Prepare for the Test You should not eat or drink anything for 4 - 8 hours before the test. You will be asked to wear a hospital gown and sign a consent form for the procedure. Jewelry should be removed from the area being imaged. Tell your health care provider: If you are pregnant If you have ever had any allergic reactions to x-ray contrast material or iodine substances If you are allergic to any medications Which medications you are taking (including any herbal preparations) If you have ever had any bleeding problems How the Test Will Feel The x-ray table is hard and cold, but you may ask for a blanket or pillow. You may feel a brief sting when the numbing medicine is given and a brief, sharp, stick as the catheter is inserted. You may feel some pressure as the catheter moves up into the lungs. The contrast dye can cause a feeling of warmth and flushing. This is normal and usually goes away in a few seconds. Occasionally abnormal cardiac rhythm can develop during the procedure. The doctors will monitor your heart and can treat any abnormal rhythms that develop. Other risks include: Allergic reaction to the contrast dye Blood vessel damage Blood clot traveling to the lungs, causing an embolism Excessive bleeding or blood clot, which can reduce blood flow to the leg There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most experts feel that the risk is low compared with the benefits. Pregnant women and children are more sensitive to the risks of x-rays. COMPUTED TOMOGRAPHY Pulmonary angiography (or pulmonary arteriography) is a cardiological medical procedure. Pulmonary blood vessels are x-rayed to detect arteriovenous malformations. Why the Test is Performed Direct angiography is the injection of radiocontrast into the circulation with subsequent fluoroscopy (direct Xray visualisation) of the lungs. A more common form of direct angiography, is the catheterisation of the right atrium of the heart and injection of radiocontrast into the right heart. The test is used to detect blood clots and other blockages in the blood flow in the lung (pulmonary embolism). A popular form of pulmonary angiography is computed tomography pulmonary angiography (CTPA). This involves venous contrast only. Normal Results Invasive pulmonary angiography was first performed in 1931 by Egas Moniz and colleagues.[1] Robb and You may have some tenderness and bruising at the site of the injection after the test. Steinberg described pulmonary angiography by infusion of peripheral radiocontrast.[2][3] CTPA was introduced in the 1990s as an alternative to ventilation/perfusion scanning, which relies on radionuclide imaging of the blood vessels of the lung. It is regarded as a highly sensitive and specific test for pulmonary embolism.[1] Interpretation On CTPA, the pulmonary vessels are filled with contrast, and appear white. Any mass filling defects (embolus or other matter such as fat or amniotic fluid) appears darker. Generally, the scan should be complete before the contrast reaches the left side of the heart and the aorta, which could result in artifacts. CTPA is typically only requested if pulmonary embolism is suspected clinically. If the probability of PE is considered low, a blood test called D-dimer may be requested. If this is negative, risk of a PE is considered negligible and CTPA or other scans are generally not performed. Most patients will have undergone a chest X-ray before CTPA is requested After initial concern that CTPA would miss smaller emboli, a 2007 study comparing CTPA directly with ventilation/perfusion scanning found that CTPA identified more emboli without decreasing the risk of long-term complications compared to V/Q scanning Contraindications CTPA is generally avoided in pregnancy due to the amount of ionizing radiation required, which may damage the fetus CTPA is contraindicated in known or suspected allergy to contrast media or in renal failure (where contrast agents could worsen the renal function) Acquisition The best results are obtained using multidetector computed tomography (MDCT) scanners An intravenous cannula is required for the administration of the 50-150 ml. of radiocontrast. This is injected, usually automatically, by a syringe driver, at a rate of 4 ml./second. Many hospitals use bolus tracking, where the scan commences when the contrast is detected at the level of the proximal pulmonary arteries. If this is done manually, scanning commences about 10–12 seconds after the injection has started. Slices of 1-3 mm. are performed at 1-3 mm. intervals, depending on the nature of the scanner (single- versus multidetector) State of the art CT machines can complete a scan in approximately five seconds and it is possible to complete the entire procedure (set-up, injection and scanning) in the space of five minutes. What is CT angiography? Angiography is a minimally invasive medical test that helps physicians diagnose and treat medical conditions. Angiography uses one of three imaging technologies and, in some cases, a contrast material to produce pictures of major blood vessels throughout the body. Angiography is performed using: x-rays with catheters computed tomography (CT) magnetic resonance imaging (MRI) CT imaging uses special x-ray equipment to produce multiple images and a computer to join them together in multidimensional views. In CT angiography (CTA), computed tomography using a contrast material produces detailed images of both blood vessels and tissues. What are the benefits vs. risks? If you have a history of allergy to x-ray contrast material, your radiologist may advise that you take special medication for 24 hours before CT angiography to lessen the risk of allergic reaction. Another option is to undergo a different exam that does not call for contrast material injection. If a large amount of x-ray contrast material leaks out from the vessel being injected and spreads under the skin where the IV is placed, skin damage or damage to blood vessels and nerves, though unlikely, can result. If you feel any pain in this area during contrast material injection, you should immediately inform the technologist. Women should always inform their physician and x-ray or CT technologist if there is any possibility that they are pregnant Nursing mothers should wait for 24 hours after contrast material injection before resuming breast-feeding. The risk of serious allergic reaction to contrast materials that contain iodine is extremely rare, and radiology departments are well-equipped to deal with them. Benefits Angiography may eliminate the need for surgery. If surgery remains necessary, it can be performed more accurately. CT angiography is able to detect narrowing of blood vessels in time for corrective therapy to be done. CT angiography gives more precise anatomical detail of blood vessels than magnetic resonance imaging (MRI). Many patients can undergo CT angiography instead of a conventional catheter angiogram. Compared to catheter angiography, which involves placing a catheter (plastic tube) and injecting contrast material into a large artery or vein, CT angiography is a much less invasive and more patient-friendly procedure. This procedure is a useful way of screening for arterial disease because it is safer and much less time-consuming than catheter angiography and is a cost-effective procedure. There is also less discomfort because contrast material is injected into an arm vein rather than into a large artery in the groin. No radiation remains in a patient's body after a CT examination. X-rays used in CT scans usually have no side effects. Risks There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk. What are the limitations of CT Angiography? A person who is very large may not fit into the opening of a conventional CT scanner or may be over the weight limit for the moving table. CT angiography should be avoided in patients with advanced kidney disease or severe diabetes, because xray contrast material can further harm kidney function. If a patient's heart is not functioning normally, or if there are multiple blocked blood vessels, CT angiograms may be hard to interpret. CT angiograms are not yet as reliable as selective catheter injections (performed after puncture of the artery in the groin) in imaging small tortuous arteries, particularly coronary arteries in the rapidly moving heart. TRAETMENTS INVOLVED IN PULMONARY EMBOLISM CAVAL FILTERS An inferior vena cava filter, also IVC filter a type of vascular filter, is a medical device that is implanted into the inferior vena cava to prevent fatal pulmonary emboli (PEs). Inferior vena cava filter - Gunther Tulip IVC filters are used in case of contraindication to anticoagulation, failure of anticoagulation or complication to anticoagulation in patients who have a venous thromboembolic disease or in prophylactic use for patients with a high risk of pulmonary embolism. Placement IVC filters are placed endovascularly, meaning that they are inserted via the blood vessels. Historically, IVC filters were placed surgically, but as designs changed they could be placed via the groin through a thin tube or catheter. With modern filters which can be compressed into much thinner catheters, however, access to the venous system can be obtained either via the femoral vein (the large vein in the groin),the internal jugular vein (the large vein in the neck.) or via the arm veins with one design. Choice of route depends mainly on the amount and location of blood clot within the venous system. To place the filter, a catheter is guided into the IVC using fluoroscopic guidance, then the filter is pushed through the catheter and deployed into the desired location, usually just below the junction of the IVC and the lowest renal vein. Review of prior cross-sectional imaging or a venogram of the IVC is performed before deploying the filter to assess for potential anatomic variations, thrombi within the IVC, or areas of stenoses, as well as to estimate the diameter of the IVC. Rarely, ultrasound-guided placement is preferred in the setting of contrast allergy, renal insufficiency, and when patient immobility is desired. The size of the IVC may affect which filter is deployed, as some (such as the Birds Nest) are approved to accommodate larger cavas. There are situations where the filter is placed above the renal veins (e.g. pregnant patients or women of childbearing age, renal or gonadal vein thromboses, etc.). Also, if there is duplication of the IVC, the filter is placed above the confluence of the two IVCs or a filter can be placed within each IVC. Indications for use Most filters are placed for the following reasons. Failure of anticoagulation; eg development of deep vein thrombosis (DVT) or pulmonary emboli (PE) despite adequate anticoagulation. Contraindications to anticoagulation; eg a patient at risk of PE who has another condition that puts them at risk of bleeding, such as a recent bleed into the brain, or a patient about to undergo major surgery Large clots in the vena cava or iliac veins Patients at high risk of having a PE DEATH RATE IN PE 9 8 death rate white men 7 6 death rate white women 5 death rate non white men 4 3 Retrieval Most IVC filters are permanent, but some filters are now available that are "retrievable." Retrievable filters are fitted with some sort of device (that varies from model to model) that allows them to be pulled back into a catheter (technically a "sheath") and removed from the body, often through the Jugular vein. Previously, filters that had been in the IVC for less than three weeks were considered suitable to attempt retrieval, as filters that have been in place longer might have been overgrown by cells from the IVC wall and there was an increased risk of IVC injury if the filter is dislodged. Newer designs, and developments in techniques mean that some filters can now be left in for prolonged periods and retrievals after a year are now being reported. This would include the ALN, Option, Tulip and Celect filters. death rate non white women 2 1 0 1962- 1965- 1970- 1975- 198064 69 74 79 84 Localization of PE in subject who were the victim of sudden unexpected death AREA TOTAL PERCENTAGE Major pulmonary 8 16.1 artery Right and left 10 20.4 branches Right branch 7 14.2 Left branch 2 4.1 Lobar and 7 14.2 segmental artery(unilateral) Lobar and 5 10.2 segmental artey(bilateral) Sub-segmental artery(unilateral) Sub-segmental artey(bilateral) 3 6.1 7 14.2 PROGNOSIS: The prognosis of acute PE depends on several factors among the most of the important presence of concomitant disease especially malignancy previous cardiac or PE disease, patients age, size, localization, age of PE, degree of pulmonary hypertension. Acute PE reflected by degree of pulmonary hypertension & presence of pulmonary(or) cardiac disease. CONCLUSION: Thus the pulmonary embolism is considered as a deadly infectious disease which leads to death immediately. Thus immediate diagnosis& treatment for the various symptoms of PE has been discussed thoroughly in this paper. ACKNOWLEDGEMENTS The authors wish to thank the Chairperson and Principal, for all the facilities provided and all the staff members of the department of Biomedical Engineering who have rendered their support, guidance and encouragement to us in the making of this paper. REFERENCES: Book on pulmonary embolism by M.Morpugo Book on current diagnosis and treatment in cardiology by Michael.H.Crawford Book on principles of medicine by Davidson Harrisons text book of medicine Golwalla text book of medicine Pulmonary embolism by Paul.D. stein