Anaesthetic management of obstetric emergencies

1. Anaesthetic management of obstetric emergencies Dr M Booyens Mb,chb (ufs), da (sa) Medical officer – anaesthesia – RMS Hospital

3. Content • Umbilical cord prolapse • Antepartum Hemorrhage (APH) • Postpartum Hemorrhage (PPH) • Hypertensive disorders • HELLP syndrome • Amniotic fluid embolism • Anaesthesia for obstetric patients • Maternal resuscitation

6. Indications for emergency cesarian section • True emergency vs urgent surgery • Emergency (threat to mother, baby or both): • Massive bleeding • Umbilical cord prolapse • Fetal distress • Close communication with obstetricians • Choice of anaesthetic technique • Maternal safety • Technical issues • Personal experience

7. Signs of fetal distress • Non-reassuring heart rate pattern • Late decelerations • Loss of variability • Depth of decelerations and rate recovery • Fetal Bradycardia (<80beats/min) • Fetal scalp pH<7,2 • IUGR • Meconium stained amniotic fluid

8. Umbilical cord prolapse • Cord is present in front of the presenting fetal part (cord presentation) • Leads to cord compression and fetal asphyxia Risk factors • Excessive cord length • Malpresentations • Low birth weight • Grand parity(>5) • Multiple pregnancies • AROM

9. Management • Immediate steep Trendelenburg position • Pt can be placed in a knee position – not ideal for anaesthesia • Manual elevation of presenting part by assistant • Fetus is elevated to relieve pressure on the cord • Palpate cord for pulsation to evaluate effectiveness • Patient is prepared for a general anaesthetic • If the fetus is not viable – vaginal delivery

11. Antepartum Hemorrhage • Most common obstetric emergency • High morbidity to mother and baby if not managed correctly • Uterus receives 12% cardiac output • Should be no delay in managing APH • May be concealed • Fetus at greater risk due to maternal haemorrhage Main problems • Hypovolaemia • Aneamia

12. Causes • Abruptio Placentae • Bleeding associated with pain • May be concealed retroplacental • Small concealed bleeds may be treated conservatively, but monitored closely • Placentae previa • Painless bleeding • Different degrees • Uterine rupture • Fetal distress • Very painful • Loss of contractions / uterine tone

14. Postpartum Hemorrhage • Defined: Blood loss >500ml post delivery • 4 T’s • Trauma: Vaginal tract laceration • Tumor: Retained products/placenta • Tone: Uterine Atony or Inversion • Thrombin: Clotting abnormalities

16. Management of Haemorrhage • Have a protocol set-up prior • Call for help • Give supplemental oxygen via facemask • If airway reflexes are lost or LOC = intubate • Remember your pelvic tilt – aortocaval compression • Two 14 G peripheral lines and blood for cross matching • Fluid resuscitation with crystalloids and colloids • Don’t fall behind • Consider vasopressors if haemodynamically unstable • Start appropriate monitoring of mother and fetus • Keep the patient informed – if awake

17. Cont… • Treat the cause – surgery • General anaesthesia • Blood transfusion as per situation • Rule of thumb: aim for an Hb of 7 • Individualize • Try and wait until bleeding is controlled • Hospital protocol for massive transfusion: 1:1:1 vs 3:1:1 • Consider auto transfusion devices • Correct coagulopathies with FFP, cryo and Plt • Keep your patient warm! • Continuous communication with obstetrician • Early communication with ICU

18. Uterotonic drugs Oxytocin • Synthetic • Causes uterine contraction and peripheral vasodilation • Mild antidiuretic effect • Can be given IM or IV • Rule of 3’s: 3U, every 3 min, times 3 • Infusion: 30U in 1L R/L – titrate to effect an BP Ergometrine • Ergot alkaloid derivative • Nausea and vomiting common side effect • Potent vasoconstriction – CI in hypertensive pt’s • 0,5mg IM or 0,125mg IV (slowly)

19. cont Carboprost (Prostaglandin F2a) • Effective uterine contractions • Also causes nausea, vomiting and diarrhoea • May produce bronchospasm • 0,25mg intramyometrialor IM every 15 min • Max dose of 2mg Misoprostol • Very similar effect as carboprost • Less potent bronchospasm • Can be given sublingual or PR

20. Surgical interventions • Rubbing of the uterus • Bimanual compression of uterus • Balloon cath of uterus (temporary) • B-Lynch suture • Ligation of uterine arteries • Ligation of internal iliac arteries • Hysterectomy • Reserved as last line

24. Amniotic fluid embolism • Incidence: 1:20000 deliveries • Effects due to anaphalctic reaction to fetal tissue • 86% mortality rate • 50% in the first hour • Amniotic fluid can enter through any break in the uteroplacental membrane • Fetal debris, prostaglandins and leukotrienes are involved

25. Risk factors • Age>25 • Multiparous women • Obstructed labour • Multiple pregnancy • Abruptio placentae • Uterine rupture • Placenta praevia

26. Symptoms • Sudden onset of tachypnoea, cyanosis, shock and generalized bleeding. • Three major pathophysiological manifestations • Acute pulmonary embolism • DIC • Uterine atony • Pulmonary oedema and right heart failure within the first 30min • Often a diagnosis of exclusion, but should not be last on the differential

27. Management • Mainly supportive • ABC’s • Deliver the fetus as soon as possible • Mechanical positive pressure ventilation • Inotropic support • Invasive monitoring • Coagulation monitoring and management • Uterotonic drugs • ICU admission

28. Hypertensive disorders • Pregnancy induced Hypertension • Chronic Hypertension • Preeclampsia • SBP>140mmHg or DBP>90mmHg after 20weeks gestation with proteinuria (>300mg/d) that resolves within 48h after delivery • Superimposed preeclampsia • Eclampsia • Seizures • HELLP syndrome

29. Pathophysiology • Vascular dysfunction of placenta • Leads to abnormal prostaglandin metabolism • Elevated TXA2 and decrease in Prostacyclin • TXA2 potent vasoconstrictor and promotor of plt aggregation • Decrease production of nitric oxide and increase endothelin-1 • Severe pre-eclampsia: • BP>160/110 • Proteinurea>5g/day • Increased creatinine • IUGR • Pulmonary oedema • CNS manifestations

31. Complications Neurological • Headache • Visual disturbances • Hyperexcitability • Seizures • Intracranial haemorrhage • Cerebral oedema Pulmonary • Upper airway oedema • Pulmonary oedema Cardiovascular • Decreased intravascular volume • Increased SVR • Hypertension • Heart failure Hepatic • Impaired function • Elevated enzymes • Hematoma • Rupture Renal • Proteinuria • Sodium retention • Decreased GFR • Failure Heamatological • Coagulopathy • Thrombocytopenia • Plt dysfunction • Microangiopathichemolysis

32. Management • Bed rest • Sedation • Antihypertensives • B-blokkers: Labetalol 5-10mg IV every 10min • Hydralazine 5mg Iv (max of 20mg) • Ca-channel blokkers: Nifedipine 10mg oral • MgSO4 • Delivery!!!!

34. Anaesthesia • Mild preeclampsia only requires caution and vigilance • Normal anaesthetic practices • Severe disease • Hypertension controlled and hypovolaemia should be corrected prior to surgery • Epidural is the golden standard – requires skill • Plt count> 70 for regional techniques • Invasive monitoring • Hypotension should be treated with small doses of vasopressors • Goal directed fluid therapy • Nitrocine, labetalol or MgSO4 can be used to treat hypertension • Magnesium potentiates muscle relaxants • Calcium gluconate antidote

35. Eclampsia • ABC’s • Left lateral position – bag mask ventilation • Obtain IV access • Control seizures with 4g Magnesium IV over 5-10min • Magnesium infusion @ 1g/hr • Monitor levels • Delivery with GA as soon as possible • Consult ICU for post-op

36. HELLP syndrome • Evidence of haemolysis • Falling Hb without bleeding • Haemoglobinuria • Elevated bilirubin • Elevated LDH • Fragmentation on smear • Elevated liver enzymes • AST, ALT, GGT, ALP • RUQ pain • Falling or low plt count • <100

37. Suggested technique for GA • Supine position with wedge under right hip and ramped • Preoxygenate with 100% oxygen for 3-5min • Patient is cleaned and draped • RSI • Cricoid pressure • Propofol 2mg/kg or Ketamine 1-2mg/kg iv • SUX 1,5mg/kg • Surgery is started once ETT is secured • Avoid hyperventilation (keep ETCO2>25) • Volatile agents: MAC 0,8 – avoid atomy • Consider TIVA in cases were pt is at risk of atony • Once neonate is born: give bolus of 3U oxytocin IV • Opioids may no be given • Consider post-op Abd wall blocks • Patient is extubated fully awake and reversed in the head-up position

38. Maternal resuscitation – Key points • After 20w gestation: wedge under right hip to minimize aortocaval compression • Chest compressions done over sternum • Fetus should be delivered as soon as possible • Front room c/s • Decreases aortocaval compression • Improves survival of mom and baby • Aspiration risk: intubate as soon as possible • Consider obstetric causes of arrest with H’s and T’s • Normal dosages of drugs should be used • Adrenaline

39. H’s T’s • Toxins (anaphylaxis/anaesthetic) • Tension pneumothorax • Thrombi • Cardiac • Pulmonary • Bone cement • Air • Tamponade • Trauma • qT prolongation • pulmonary hyperTension • Hypoxia • Hypovolaemia • Hyper/HypoKalemia • Hydrogen ion (acidosis) • Hypothermia • Hypoglycaemia • malignant Hyperthermia • Hypervagal

41. Questions?