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TemplateDr Unnikrishnan PP.G.StudentMedical College, Trivandrum

Maternal Collapse due to Embolism

THROMBOEMBOLISM

AMNIOTIC FLUID EMBOLISM

VENOUS AIR EMBOLISM

Anaestesiologist is often involved in the resuscitation of patients with embolic disorders

IMPORTANT CAUSES

VENOUS• .

THROMBO EMBOLISM• .

Deep Vein Thrombosis [DVT] & Pulmonary Thrombo Embolism [PTE] are the important manifestations

DVT is the most common etiology for Pulmonary Thrombo Embolism

15-24% of women with untreated DVT experience a pulmonary embolus

PTE accounts for 15% of direct maternal mortality

VENOUS THROMBOEMBOLISM

CHESTNT’S OBSTETRIC ANESTHESIA, 4/e[2009],p:837,838

Changes in coagulation

AETIOLOGY

20% DECREASE IN PLATELET COUNT

PLATELET FUNCTION INCREASED

INCREASED FACTORS I,V,VII,VIII,IX,X,XII

INCREASED THROMBIN GENERATION

FIBRINOLYSIS NORMAL / DECREASED

SHNIDER AND LEVINSONS ANESTHESIA FOR OBSTETRICS,4/e

Venous stasis

Vascular damage: caesarean > vaginal

Obstetric conditions: PIHMultiple pregnancy

AETIOLOGY

VIRCHOW’S TRIAD : HYPERCOAGULABILITY, STASIS, ENDOTHELIAL INJURY

Increasing age

Prolonged immobilization

Obesity

Thrombophilia

Previous thromboembolism

Cesarean delivery

RISK FACTORS

ASRA GUIDELINES [THIRD EDITION];Reg Anesth Pain Med 2010

PATHOPHYSIOLOGY

OCCLUSION

↑PVR,PAP

RV OVERLOAD IV SEPTUMLV

↓LV VOLUME↓COMPLIANCE

↓BP ↓CORONARY PERFUSION PRESSURE

RV ISCHEMIA RV FAILURE

PATHOPHYSIOLOGY

↓PaO₂↑P(A-a)O₂IMPAIRED GAS EXCHANGE [↑DEAD SPACE,SHUNT,HYPOXEMIA,DECREASED DIFFUSION]V/Q MISMATCHALVEOLAR HYPER VENTILATION↑AIRWAY RESISTANCE↓COMPLIANCE[EDEMA, HEMORRHAGE,LOSS OF SURFACTANT]ATELECTASIS

CLINICAL FEATURES: SYMPTOMS

DYSPNOEAPALPITATIONANXIETYCHEST PAIN [PLEURITIC]COUGHHEMOPTYSISSYNCOPECOLLAPSE

CLINICAL FEATURES: SIGNS

TACHYPNOEACREPITATION↓ED BREATH SOUNDSFEVERTACHYCARDIAACCENTUATED S₂JUGULAR VENOUS DISTENSIONLEFT PARASTERNAL HEAVEHEPATIC ENLARGEMENTTHROMBOPHLEBITIS/ FEATURES OF DVT

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 • Score 2.0 to 6.0 - Moderate • Score <2.0 - Low

Alternate interpretation• Score > 4 - PE likely. Consider diagnostic imaging. • Score 4 or less - PE unlikely. Consider D-dimer to rule out PE.

ECG

DIAGNOSTIC EVALUATION

RV STRAIN PATTERNRIGHT AXIS DEVIATIONP-PULMONALET INVERSION IN V₁-V₄SUPRAVENTRICULAR ARRHYTHMIASS₁Q₃T₃ PATTERN: DEEP S IN L₁ DEEP Q IN L₃ T INVERSION IN L₃

CHEST X-RAY

DIAGNOSTIC EVALUATION

BLANCHING / OLIGEMIC AREAWESTERMARK’S SIGNHAMPTONS HUMPELEVATED HEMIDIAPHRAGMFOCAL INFILTRATESPLEURAL EFFUSIONATELECTASIS

HAMPTON’S HUMP

INVASIVE HEMODYNAMIC MONITORING

ARTERIAL BLOOD GAS ANALYSIS

ELISA FOR D-DIMER

DIAGNOSTIC EVALUATION

NORMAL TO LOW PULMONARY ARTERY OCCLUSSION PRESSUREINCREASED MEAN PULMONARY ARTERY PRESSUREINCREASED CVP

WIDENED P(A-a)O₂REDUCED PaO₂REDUCED PaCO₂

HIGH SENSITIVITY ESPECIALLY WHEN COMBINED WITH A USG OF LEGLOW SPECIFICITY, SINCE D-DIMER APPEARS IN NORMAL PREGNANCY SINCE SECOND TRIMESTER

VENTILATION PERFUSION SCAN

DIAGNOSTIC EVALUATION

HIGH PROBABILITY SCAN:> 2 MODERATE TO LARGE PERFUSION DEFECTS INVOLVING >25% OF LUNG SEGMENT WITH INTACT VENTILATION

• START ANTICOAGULATIONHIGH PROBABILITY

SCAN & HIGH CLINICAL SUSPICION

• SPIRAL CT• PULMONARY ANGIOGRAPHYINDETERMINATE

SCAN & HIGH CLINICAL SUSPICION

SPIRAL CT

DIAGNOSTIC EVALUATION

HIGH SENSITIVITY AND SPECIFICITY

↓SED REQUIREMENTS FOR FURTHER TESTING

HENCE MOST COST EFFECTIVE

LESSER RADIATION TO FOETUS THAN V/P SCAN

HIGHER MATERNAL BREAST TISSUE EXPOSURE

DIAGNOSTIC EVALUATION

PULMONARY ANGIOGRAPHY

INVASIVEINTRALUMINAL FILLING DEFECT

MAGNETIC RESONANCE VENOGRAPHY

ECHOCARDIOGRAPHY

COMPRESSION USG

DIAGNOSTIC EVALUATION

SENSITIVITY AND NEGATIVE PREDICTIVE VALUE HIGH WHEN COMBINED WITH A LOWER LIMB USGCAN DETECT A CLOT OR CONSEQUENT RV DYSFUNCTIONOBVIATE NEED FOR INVASIVE PROCEDURESHASTEN START OF ANTICOAGULATION

Decreases the risk 10 fold

Begun when the high risk period begins and continued for 5-10 days

UFH : 5000 U subcutaneously Q12H

Enoxaparin : 40 mg subcutaneously Q24H

Ensure availability of FFP at the time of delivery

PROPHYLAXIS PHARMACOLOGICALINTERMITTENT PNEUMATIC COMPRESSIONELASTIC STOCKINGS

UNFRACTIONATED HEPARIN [UFH]#

THERAPY - DVT

5000 U [80-100 U / KG] IV LOADING DOSE FOLLOWED BY 15-20 U / KG / HOUR IV INFUSIONaPTT KEPT AT 1.5 TO 2.5 TIMES NORMALIV INFUSION X 5-7 DAYS S/C HEPARINDOSE MAY HAVE TO BE ↑ED BY 50% IN 2 ND AND 3 RD TRIMESTERSDISCONTINUED WHEN PATIENT BEGINS ACTIVE LABOR / 24 HOURS BEFORE CSWARFARIN CAN BE STARTED; WHEN INR 2-3, HEPARIN CAN BE STOPPEDANTICOAGULATION CONTINUED 6 WEEKS POSTPARTUM

#Sipes SL,Venous thromboembolic disease in pregnancy ;Semin Perinatol 1990#American College of Obst & Gyn Comm. on practice;ACOG Practice bulletin no:19,AUG2000

THERAPY - DVT

GREATER ANTITHROMBOTIC ACTIVITY [ANTIFACTOR Xa]THAN ANTICOAGULANT ACTIVITY [ANTIFACTOR IIa]DON’T AFFECT aPTT

#Sipes SL,Venous thromboembolic disease in pregnancy ;Semin Perinatol 1990#American College of Obst & Gyn Comm. on practice;ACOG Practice bulletin no:19,AUG2000

LOW MOLECULAR WEIGHT HEPARIN [LMWH]

Enoxaparin 40 MG OD-BD [1 MG = 100 U] PROPHYLAXIS 30-80 MG BD THERAPEUTIC ANTICOAGULATION

Dalteparin 2500-5000 U OD-BD THROMBOPROPHYLAXIS100 U/KG BD THERAPEUTIC ANTICOAGULATION

PULMONARY EMBOLISM-TREATMENT: GOALS

SUPPORT MATERNAL CIRCULATION

PROVIDE ADEQUATE MATERNAL AND FOETAL OXYGENATION

PREVENT RECURRENCE

MINIMIZE LONG TERM MORBIDITY

PULMONARY EMBOLISM-TREATMENT #

Standard UFH; 80-150U/kg followed by continuous infusion of 15-25 U/kg/hour to keep aPTT at twice normal values

#American College of Obst & Gyn Comm. on practice;ACOG Practice bulletin no:19,AUG2000#Weiner CP et al; management of thromboembolic disease during pregnancy; Clinical Obstet Gynecol 1985

ABSOLUTEINTRACRANIAL BLEEDSERIOUS ACTIVE BLEEDINGRECENT BRAIN/EYE/SPINAL SURGERYSEVERE THROMBOCYTOPENIARELATIVEHEMORRHAGIC DIATHESISRECENT STROKERECENT MAJOR SURGERYSEVERE UNCONTROLLED HYPERTENSION [DBP>110 MM OF HG]BACTERIAL ENDOCARDITIS

CONTRA INDICATIONS- ANTICOAGULATION

Transvenous implantation of an IVC filter

INFERIOR VENACAVAL INTERRUPTION

ANTICOAGULATION CONTRAINDICATED ANTICOAGULATION FAILED PROXIMAL DVT RECURRENT EMBOLI

THROMBOLYSIS

MASSIVE EMBOLISM WITH HEMODYNAMIC INSTABILITY

ECHO EVIDENCE OF RV HYPOFUNCTIONEXTENSIVE ILEOFEMORAL THROMBOSIS40% OBSTRUCTION ON PULMONARY

ANGIOGRAPHY

Monitoring of coagulation: Thrombin time [Most sensitive]aPTTFDP

Complications:Maternal hemorrhage, Placental abruption

THROMBOLYSIS

STREPTOKINASE

UROKINASE

RECOMBINANT TISSUE PLASMINOGEN ACTIVATOR [ rt- PA ]

THROMBOLYSIS

2,50,000 IU OVER 30 TO 60 MINUTES FOLLOWED BY 1,00,000 IU/HOUR FOR 24 HOURS

LESS ANTIGENICINITIAL DOSE 4400 IU FOLLOWED BY 4400 IU / KG /HOUR

CLOT SPECIFICDOES NOT INTRODUCE SYSTEMIC FIBRINOLYSIS10 MG IV BOLUS ; FOLLOWED BY 90 MG IN 2 HOURS

SURGICAL EMBOLECTOMY

THROMBOLYSIS CONTRAINDICATED THROMBOLYSIS FAILEDRAPIDLY DETERIORATING PATIENT

ANAESTHETIC IMPLICATIONS- ANTICOAGULATED PATIENT

ANTICIPATE AIRWAY BLEEDING

ARRANGE BLOOD PRODUCTS

ANTICOAGULATION & NEURAXIAL BLOCKADE

AMNIOTIC FLUID

EMBOLISM

INCIDENCE 1 IN 8000- 1 IN 30,00025-80% MATERNAL MORTALITY50% FOETAL DEATH

AMNIOTIC FLUID EMBOLISM

DEVASTATING EMERGENCY

HIGH MORTALITY

NEUROLOGICAL DYSFUNCTION

HOW DOES IT STARTS?

PATHOPHYSIOLOGY

AMNIOTIC FLUID ENTRY

ACTIVATES PROCOAGULANT SYSTEM DIC

PULMONARY MICROEMBOLIZATION

FIRST PHASE[30 MIN] SECOND PHASE

BIPHASIC RESPONSE

PULMONARY VASOSPASM

PULMONARY HYPERTENSION

RIGHT HEART DYSFUNCTION

LVF, PULMONARY EDEMA

ARDS

DIC

“ANAPHYLACTOID SYNDROME OF PREGNANCY”

?COMMON MECHANISM

AFE

SEPSIS

ANAPHYLAXIS

CLINICAL FEATURES

A/C RESPIRATORY FAILURE, HYPOXIA

HEMODYNAMIC COLLAPSE

COAGULOPATHY

ANXIETY NAUSEA CHILLS• .

CYANOSIS COMA• .

More details: AFE Registry Criteria by Clark et al 1983-1995

DIFFERENTIAL DIAGNOSIS

•PLACENTAL ABRUPTION

•ECLAMPSIA

•UTERINE RUPTURE

OBSTETRIC CONDITIONS

•PULMONARY EMBOLISM , VAE

•M.I., CVA, ASPIRATION PNEUMONIA

•ANAPHYLAXIS

NON OBSTETRIC CONDITIONS

•TOTAL SPINAL ANESTHESIA

•LOCAL ANESTHETIC TOXICITY

ANESTHETIC COMPLICATIONS

DIAGNOSIS

CHEST X-RAY• NORMAL / DIFFUSE

PULMONARY OEDEMA

INVASIVE MONITORING• ↑CVP,PAP,PACWP

DIAGNOSIS

IMMUNOSTAINING

• MONOCLONAL ANTIBODY DIRECTED AGAINST A GLYCOPROTEIN FOUND IN AMNIOTIC FLUID

DETECTION OF ZINC COPROPORPHYRIN IN MATERNAL PLASMA• A COMPONENT OF MECONIUM

MANAGEMENT

• OXYGEN• INTUBATION• MECHANICAL VENTILATIONOXYGENATION &

VENTILATION

• LARGE BORE IVA• IV FLUIDS & BLOOD PRODUCTS• INTRA ARTERIAL / PA CATHETER• INOTROPES

HEMODYNAMIC SUPPORT

MANAGEMENT

• CRYOPPT,FFP,PLATELETS,BLOOD• CRYOPPT REPLACES FIBRINOGEN &

FIBRONECTIN HELP IN REMOVAL OF CELLULAR DEBRIS BY RES

• ?EPIDURAL HEMATOMA

CORRECT COAGULOPATHY

• CCF,PULMONARY EDEMA,ARDS• ARF, NEUROLOGICAL SEQUELAE

TREAT SEQUELAE OF SHOCK

MANAGEMENT

• NECESSARY TO SUCCESSFULLY PERFORM CPR IN THIRD TRIMESTERDELIVERY

FOETAL MONITORING

VENOUS AIR EMBOLISM

• ..

Malinow et al published the first study of VAE during cesarean delivery in 1987¹

Subclinical VAE occurred in 97% of patients receiving GA for cesarean delivery²

VAE occurred in approx 67% of patients receiving neuraxial anesthesia³

1.Malinow AM et al,Anesthesiology 19872.Lew TWK et al, VAE during CS,Anesth Analg 19933.Handler JS,VAE during CS Reg Anesth 1990

VENOUS AIR EMBOLISM

Pressure gradient as small as -5 cm of H₂O

PATHOPHYSIOLOGY

Surgical Field

Heart

RISK FACTORS

PATHOPHYSIOLOGY

LEFT UTERINE DISPLACEMENT

TRENDELENBERG POSITION

REDUCED CVP

EXTERIORISATION OF UTERUS

PATHOPHYSIOLOGY

AIR

P-HTN

V/Q MISMATCH

IMPAIRED GAS

EXCHANGE

Paradoxical Air Embolism may occur in case of intracardiac defects

PATHOPHYSIOLOGY

AIR TRAP RV-PA

PUL BLOOD FLOW STOP ↓LV FILLING

↓COCARDIAC ARREST

Morbidity and mortality depends on

CLINICAL FEATURES

CLINICAL FEATURES

VOLUME OF AIRRATE OF INFUSION OF AIRSITE OF EMBOLIZATION>3 ML / KG OF AIR IS FATAL

GASPING RESPIRATIONHEAVY, NON RADIATING RETROSTERNAL CHEST PAIN

ARRHYTHMIARAISED CVPHYPOTENSIONDECREASED OXYGEN SATURATIONCHANGE IN HEART SOUNDSMILL WHEEL MURMERINCREASED AIRWAY PRESSURE

Trans esophageal echo

Doppler Ultrasound

ETCO₂ETN₂PULMONARY ARTERY PRESSURECVPECG

MONITORING / DIAGNOSIS

DETECT <0.015 ML / KG/MIN OF AIRHIGHLY SENSITIVE

COMBINATION OF A PRECORDIAL DOPPLER & ETCO₂ HAVE HIGH SENSITIVITY & SPECIFICITY

P-WAVE CHANGES, ST-T ↓,HEART BLOCK, BRADYCARDIA

PREVENT FURTHER AIR ENTRY

MANAGEMENT

NOTIFY SURGEONFLOOD THE SURGICAL FIELD WITH SALINEJUGULAR COMPRESSIONLOWER THE HEAD / 15⁰ HEAD DOWN TILT IN LEFT LATERAL DECUBITUS POSITION-DURANTS POSITION

TREAT INTRAVASCULAR AIR

MANAGEMENT

ASPIRATE AIR VIA CENTRAL VENOUS CATHETER [>200ML OF FOAM OVER A PERIOD OF 3 MINUTES]DISCONTINUE NITROUS OXIDEFiO₂ :1.0PRESSORS /INOTROPESCHEST COMPRESSIONNEURODIAGNOSTIC IMAGINGHYPERBARIC O₂ THERAPY IN PARADOXICAL AIR EMBOLISM

5-10⁰ HEAD UP TILT WHEN UTERUS IS EXTERIORIZED

PRECORDIAL DOPPLER MONITORING IN HIGH RISK CASES

ADEQUATE HYDRATION TO RAISE CVP AND LA PRESSURE

PREVENTION

REFERENCES

•Chestnut’s Obstetric Anesthesia Principles and Practice, David H. Chestnut,[2009] 4/e•Shnider and Levinsons anesthesia for obstetrics,4/e•Why Mothers Die 2004-2005 Report; the Confidential Review of Maternal Deaths in Kerala•ASA Abstracts, Cardiac Arrest during Labor: Amniotic Fluid Embolism with Thrombus in Patent Foramen Ovale. Aparna Dalal, M.D., Mark Shulman, M.D. Anesthesiology, Caritas St. Elizabeth's Medical Center, Boston, MA, Anesthesiology 2008; 109 A1337• Martin SR, Foley MR. Intensive care in obstetrics: an evidence-based review. Am J Obstet Gynecol. 2006 Sep;195(3):673-89. • Porat S, Leibowitz D, Milwidsky A, Valsky DV, Yagel S, Anteby EY.Transient Intracardiac thrombi in Amniotic fluid embolism.BCOG. 2004 May;111(5):506-10.• Saad A, El-Husseini N, Nader GA, Gharzuddine W. Echocardiographically detected mass "in transit" in early amniotic fluid embolism. Eur J Echocardiogr. 2006 Aug;7(4):332-5. Epub 2005 Aug 10.

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