Pulmonary embolism and anestheisa

1. Pulmonary embolism and anestheisa Presented by R1 李欣融

2. Pulmonary embolism • Pre-operative Considerations -from blood clots, tumor cells, air, amniotic fluid, foreign material -prolonged bed ridden, postpartum state, fracture of long bone, orthopedic surgery with tournique use, carcinoma, heart failure, obesity, OP time>30 mins, hypercoagulability (antithrombin III, protein S, C and plasminogen-activator deficiency)

3. PATHOPHISIOLOGY • Increase the dead space, PaCO2↑, hypoxemia vasoconstriction and reflex PVR increased  V/Q mismatch  shunt • Pulmonary surfactant loss (24-48 hrs) • Pulmonary infarctions • Pulmonary hypertension, increased RV afterload, RV failure

4. Diagnosis • Dyspnea, tachypnea, chest pain, hemoptysis, whezzing • ABG: hypoxemia with respiratory alkalosis; Arterial to end-tidal CO2 gradient increase in PE, as an adjunct to unmasking silent pulmonary embolismThe Lancet Ltd, Volume348(9043), 21/28 December 1996  p 1733 • CXR: wedge-shaped density, elevated diaphragm, enlarged pulmonary trunks • Cardiac signs: tachycardia, wide splitting S2, systemic hypotension with increased CVP

5. Diagnosis • EKG: new right axis deviation, RBBB, tall peaked T waves, a finding of an S wave in lead I, a Q wave in lead III or an inverted T wave in lead III, and new T-wave inversion in leads V1 through V4 • Normal lead 2, rather than to lead 3 • Lung scan • Pulmonary angiogram

6. From:   Goldhaber: Ann Intern Med, Volume 136(9).May 7, 2002.691-700

9. Treatments • The best treatment for pulmonary embolism is prevention. • Heparin 5000U q12h pre-op or immediately post-op in high risk patients • Oral; warfarin, aspirin or dextran therapy together • High elastic stockings and pneumatic compression

10. Treatments • Heparin-APtt: 1.5-2.4 • Low molecular weight heparin-subcutaneous at a fixed dose without monitor • Warfarin start with heparin concurrent for 4-5 days overlap • INR: 24 hrs apart • Inferior vena cava umbrella filter for bleeding tendency p’ts

11. Anesthetic Considerations • Pre-op management • Hx of pulmonary embolism-anticoagulant ;if episode >1 year, the risk of interrupting drugs is low • Spinal or epidural anaesthesia->risk of vertebral canal haematoma ↑, permanent paraplegia • Reduced by not performing such procedures within 4 hours of the last dose of low dose unfractionated heparin

12. Anesthetic Considerations • LMWH at 8 pm/evening, starting the day before surgery and continuing post-op • Today surgery: a neuroaxial block is to be undertaken will be mobile until the block is inserted. Low molecular weight heparin intra-op, at least one hour after the procedure, as recommended by Vandermeulen et al. --British Medical Journal 2000.Volume321(7267) 21 October 2000 

13. Intraoperative management • Vena cava filter placed percutaneously under local anesthesia with sedation • Regional anesthesia for hip surgery decrease the post-op deep vein thrombosis and pulmonary embolism • Inotropic agent support when embolectomy • Opioid, etomidate, ketamine • Cardiopulmonary bypass

14. Transesophageal Echocardiography • The RPA  branches to the right lobar pulmonary arteries can be followed. • The LPA  interposition of the left main bronchus interferes with the ultrasound beam in the middle portion of the left pulmonary artery. Therefore, thromboembolism is more difficult to detect in the LPA.

15. Transesophageal Echocardiography

16. During Total Knee Arthroplasty with Cement1998 by The Journal of Bone and Joint Surgery, IncorporatedVolume 80-A(3) • Medullary canal penetration during endoprosthetic procedures and intramedullary stabilization of fractures of the long bones  bone marrow into the circulatory system • Healy et al., little fat and no polymethylmethacrylate monomer activation of the clotting system • Venous stasis and intimal damage  hypercoaguable state  thrombus formation.

19. Discussion • The intensity of the echogenic showers ≠the intraoperative hemodynamic changes. • Embolic score , hemodynamic changes ≠ cement insert • Duration of tourniquet ≠ the intensity of the embolic showers • Embolic particles > 0.5 cm in maximum diameter  PVR ↑, as a critical variable morbidity and mortality • All-or-none effect of the tournique

20. RCC involved IVC • Transesophageal Echocardiography and Basket Catheter Can Prevent Tumor Embolism in a Patient with Renal Cell Carcinoma--1998 American Society of Anesthesiologists, Inc. • Easily available • Easily pushed out and removed from the incision of the inferior vena cava. • Effectively to prevent massive tumor embolism Minor pulmonary embolism could not be prevented • Further investigation would be needed to clarify the effectiveness of the basket catheter for the prevention of pulmonary embolism.

21. Malignant RCC extending to IVCThe American Journal of surgery, volume 176 August 1998 • 5 y/o survival rate:48% to 68% after completely resected, aggressive approach (IVC thrombus remove) means • Diagnosis: ultrasound, CT (can’t accurate at superior margin), MRI, venography, Current technology of gradient recall Acquisition in steady state (GRASS), color doppler

23. Intra-Op considerations • Prevention of tumor embolism control IVC above and below tumor by filter • Minimal blood loss  vascular isolation from IVC • Maintance the hemodynamic stability by ensure the venous return  Centrifual flow shunt, cardiopulmonary bypass • Reduce ischemic time of vital organ

25. Anesthetic considerations • Pre-OP evaluation of tumor extent • Intra-OP monitor : TEE, entidal CO2, CVP, Swan-Guanz, EKG, pulse oximeter • Prepare for cardiopulmonary bypass and deep hypothermic cardiac arrest • Extracorporeal venous shunting ※ J. Clin. Anesth,vol 13,December,2001

26. Anesthesia intervention • Thoracic, but Not Lumbar, Epidural Anesthesia Improves Cardiopulmonary Function in Ovine Pulmonary Embolism--2001 by International Anesthesia Research Society.Klinik und Poliklinik für Anästhesiologie und Operative Intensivmedizin, Universitätsklinikum Münster, Münster, Germany • Epidural anesthesia-induced sympathetic blockade,( thoracic and lumbar levels), • (I) 6 mL bupivacaine 0.175% (Thoracic Epidural Anesthesia [TEA] group), 6 mL saline 0.9% (TEA-Control group), respectively, via an epidural catheter (T3 level). • (II) 2.8 mL bupivacaine 0.375% (Lumbar Epidural Anesthesia [LEA] group), 2.8 mL saline 0.9% (LEA-Control group) epidurally (L4 level). • Embolization : IV injection of au- tologous blood clots (Experiment 1, 0.75 mL/kg; Experiment 2, 0.625 mL/kg).

31. Anesthesia intervention • Results: TEA was associated with significantly heart rates, decreased mean pulmonary artery pressures and central venous pressures, and significantly higher stroke volume index and oxygenation in comparison with the TEA-Control group. • TEA significantly reduced, and LEA significantly increased, hemodynamic deterioration, suggesting beneficial effects of TEA on cardiopulmonary function during pulmonary thromboembolism.

32. Thanks for your attention!