<prompt> A 60-year old obese male with a history of chronic smoking since childhood presents in ICU with pelvic fracture due to fall from height. On the 4th day of the ICU stay, he developed sudden tachypnoea, fall in SpO2 and hypotension. On 2D echo, there was a dilation of right ventricle and tricuspid regurgitation. What would be the next immediate step?D-dimer assayAdministration of heparinPericardiocentesisSystemic thrombolysis  <response>: Ans. D . Systemic thrombolysis Ref: Harrison 19e p1631-1637, 18e p2170-2177; Sabiston 19e p295-297; Schwartz 9e p787-789: Bailey 26e p917Clinical picture mentioned in this question is highly suggestive of deep venous thrombosis leading to pulmonary embolism. As the patient has developed pulmonary embolism with hypotension and tachypnea, the immediate step would be Systemic thrombolysis.Anticoagulation is the foundation for successful treatment of DVT and PE. Immediately effective anticoagulation is initiated with a parenteral drug: unfractionated heparin UFH, low-molecular-weight heparin LMWH, or fondaparinux. One should use a direct thrombin inhibitors argatroban, lepirudin, or bivalirudin in patients with proven or suspected heparin-induced thrombocytopenia. Parenteral agents are continued as a transition or bridge to stable, long-term anticoagulation with a vitamin K antagonist exclusively warfarin in the United States. Warfarin requires 5-7 days to achieve a therapeutic effect. During that period, one should overlap the parenteral and oral agents.- Harrison 18e p2173Successful fibrinolytic therapy rapidly reverses right heart failure and may result in a lower rate of death and recurrent PE by 1 dissolving much of the anatomically obstructing pulmonary arterial thrombus, 2 preventing the continued release of serotonin and other neurohumoral factors that exacerbate pulmonary hypertension, and 3 lysing much of the source of the thrombus in the pelvic or deep leg veins, thereby decreasing the likelihood of recurrent PE. The preferred fibrinolytic regimen is 100 mg of recombinant tissue plasminogen activator tPA administered as a continuous peripheral intravenous infusion over 2 hours. Patients appear to respond to fibrinolysis for up to 14 days after the PE has occurred. Contraindications to fibrinolysis include intracranial disease, recent surgery, and trauma. The only FDA-approved indication for PE fibrinolysis is massive PE.- Harrison 18e p2173.Pulmonary EmbolismRisk factors for pulmonary embolism are the risk factors for thrombi formation within venous circulation.Calf venous thrombosis: Low risk for embolismThrombosis of larger veins: High risk for embolism due to loosely attached thrombus to venous wallMC site for DVT: Calf veinsQMC source for pulmonary emboli: Proximal vein of lower extremityQ femoro-popliteal and iliac veinPulmonary EmbolismRisk Factors for Pulmonary Thromboembolism Age increasing ageQ Obesity Q Immobility bed rest 4daysQ PregnancyQ and PuerperiumQ High dose estrogen therapyQ Surgery trauma especially of pelvis, hip or lower limbQ Malignancy especially pelvis, abdominal, metastatic Heart failureRecent MIQ Nephrotic syndromeQ Inflammatory bowel diseaseQ PolycythemiaQ PNHQ or Lupus anticoagulant Behcets syndromeQ HomocystinuriaQ Paralysis of lower limb Varicose veins, InfectionClinical features:Symptoms: Dyspnea chest pain, hemoptysis and coughSigns: Tachypnea MCQ. fever, unilateral leg swelling, wheeze, pleural friction rubAny patient with high likelihood of pulmonary embolism on clinical evaluation straightaway undergoes imaging tests, while a patient with low clinical likelihood should first undergo D-dimer test.Factors for Clinical Assessment of Pulmonary Embolism Clinical signs and symptoms of DVTQ An alternative diagnosis is less likely than pulmonary embolism Heart rate 100minQ HemoptysisQ Immobilization or previous surgery in 4 weeksQ Previous DVTPEQ MalignancyQ on treatment, treatment in past 6 months ECG Changes in Pulmonary EmbolismSinus tachycardia: MC and non-specific finding on ECGQFeatures of Acute Right Heart StrainHighly predictive of PE Acute right axis deviation P pulmonale Right bundle branch block Inverted T waves ST segment change S1Q3T3Q: Seen in 12 patients- S wave in lead I- Q wave in lead III- Inverted T wave in lead III- S wave in lead I, II. and III S1S2S3Diagnosis:D-dimer: Excellent screening test for the diagnosis of PEQ.Best investigation in clinical suspicion of PE: Multidetector CTQ.Eung scanning is now a 2nd line diagnostic test for PE.Pulmonary angiography: Gold standard for diagnosis of PEQ but expensive and cumbersomeTreatment:Anticoagulation is the foundation for successful treatment of DVT and PE. Immediately effective anticoagulation is initiated with a parenteral drug, unfractionated heparin UFHQ.The only FDA-approved indication for PE fibrinolysis is massive PEQ.Pulmonary embolectomy: The risk of intracranial hemorrhage with fibrinolysis has prompted a renaissance of surgical embolectomy. 