Outline Common causes of admissions to the ICU Critical Care - PDF document

6/1/2013 Outline • Common causes of admissions to the ICU Critical Care • Physiologic changes of pregnancy of the Obstetric Patient • Causes of obstetrical hemorrhage • Review amniotic fluid embolus (AFE) Kristina Sullivan, MD • Discuss pre-eclampsia/eclampsia Associate Professor Department of Anesthesia • ARDS in the pregnant patient Division of Critical Care Medicine • Fetal outcomes Case Report Case Report Following admission she was given prostaglandin 29 yo G1P0 woman was admitted at 39 intravaginal gel. 5 hours later she had spontaneous weeks gestation for induction of labor. She rupture of membranes followed by rapid had a h/o IDDM since the age of six. She progression of labor. A tetanic contraction of her had not suffered any complications related to uterus occurred and she was moved to the OR. her diabetes. Her pregnancy had been She was noted to be fully dilated and the decision was made to proceed with delivery by vacuum uncomplicated. extraction. The baby was born with Apgars of 5 and 8. Davies et al, Can J Anesth, 1999; 46: 456-459 Davies et al, Can J Anesth, 1999; 46: 456-459 1

6/1/2013 Case Report Case Report Coagulation studies revealed a PT of 27.5, a PTT of 149 and a fibrinogen of 60. Her Hgb was 8.6. Her delivery was complicated by a fourth degree She received embolization of the vaginal arteries vaginal tear. Following delivery of the placenta the and was transferred to the ICU. Over the next patient received oxytocin, and the tear was several hours the patient continued to bleed repaired under local. Excessive vaginal bleeding profusely despite ongoing resuscitation and was noted but uterine tone was felt to be good. correction of her coagulopathy. She was taken to The patient was resuscitated for ongoing the OR and received a hysterectomy to control the hemorrhage despite good uterine tone. bleeding. She recovered without sequelae. Davies et al, Can J Anesth, 1999; 46: 456-459 Davies et al, Can J Anesth, 1999; 46: 456-459 Obstetric Admissions to the Intensive Care Unit: Epidemiology Outcomes and Severity of Illness • Critical illness in a pregnant woman affects ~0.3% of pregnancies • 0.07-1.35% of deliveries require maternal ICU admission • Maternal mortality rates 2-30% • Majority of women are admitted post-partum (~70%) Pollock et al, Intensive Care Med 2010; 36: 1465 Selo-Ojeme et al, Arch Gynecol Obstet 2005; 272: 207 Mirghani et al, Int J Obstet Anesth 2004; 13: 82 Gilbert et al, Obstet and Gynecol, 2003; 102: 897-903 RWJ; adm 1991-1998 Loverro et al, Arch Gynecol Obstet, 2001; 265:195-198 *SAPS score predicts Mahutte et al, Obstet and Gynecol 1999; 94: 263-266 Is mortality prediction feasible in obstetric patients? mortality in ob pts adm Kilpatrick et al, Chest,1992; 101:1407-12 Gilbert et al, Obstet and Gynecol, 2003; 102: 897-903 with medical diagnoses 2

6/1/2013 Obstetric Admissions to the Obstetric Admissions to the Intensive Care Unit Intensive Care Unit • Most women admitted were young, multiparous, • McGill University ICU services preterm and postpartum • Retrospective analysis • Minority had preexisting medical problems that • 131 OB admissions (GA = 14 weeks and later plus contributed to their admission: 6 weeks postpartum) from 1991-1997 – Cardiac disease, Asthma, Blood dyscrasia, • Incidence: 0.3% of all deliveries Chronic HTN • 78% admitted postpartum • 3 deaths out of 131 admissions: massive • Mortality rate = 2.3% intracranial bleed, autoimmune cirrhosis, mixed CTD with sepsis Mahutte et al, Obstet and Gynecol, 1999; 94: 263-266 Mahutte et al, Obstet and Gynecol, 1999; 94: 263-266 Obstetric Admissions to the Intensive Care Unit: Obstetric Admissions to the 5 most common reasons Intensive Care Unit 1. Hemorrhage  abnormal placentation, uterine atony, lacerations, retained products of conception, severe coagulopathy/DIC 2. Hypertension  preeclampsia/eclampsia with or without HELLP ( H emolysis, E levated L iver enzymes, L ow P latelet count), pheochromocytoma 3. Cardiac disease  valvular diseases, cardiomyopathy, arrhythmias 4. Respiratory disorders  pulmonary edema, asthma 5. *Infection  pyelonephritis, chorioamnionitis Mahutte et al, Obstet and Gynecol, 1999; 94: 263-266 Mahutte et al, Obstet and Gynecol, 1999; 94: 263-266 *Snyder et al, J Matern Fetal Neo Med 2013; 26(5): 503-506 3

6/1/2013 Pregnant and Post partum admissions to the Respiratory Changes in Pregnancy ICU: a systematic review Pollock et al; Intensive Care Med 2010; 36: 1465-1474 Pulmonary Function • 40 eligible studies from several databases reporting outcomes for 7,887 women were analyzed (all retrospective Forced Expiratory Volume No change and majority single center) in 1 second • 24 studies developing countries, 15 from developing Functional Residual Decreased 10-25% countries and 1 from US and India Capacity • Confirms low incidence of ICU admission (median Total Lung Capacity Minimal decrease 2.7/1000) • Most common reasons for admission: Minute Ventilation Increased 20-40% – Hypertensive d/o of pregnancy Alveolar Ventilation Increased 50-70% – Obstetrical hemorrhage • Higher rate of mortality in developing countries (14% vs. 3%) Lapinsky S., Crit Care Med, 2005 Vol. 33, No. 7 1616-1622 Cardiovascular Changes in Lung Volume Changes in Pregnancy Pregnancy Hemodynamics Nonpregnant lung volumes Pregnant lung volumes Heart Rate Increased 10-30% Pulmonary Artery No change Occlusion Pressure Cardiac Output Increased 30-50% Systemic Vascular Decreased 20-30% Resistance Pulmonary Vascular Decreased 20-30% Resistance Lapinsky S., Crit Care Med, 2005 Vol. 33, No. 7 1616-1622 Mendoza-Asensi, Clin Pulm Med, 2009; 16:21-27 4

6/1/2013 Cardiovascular Changes in Pregnancy Arterial Blood Gas (continued) in the Pregnant Patient • Blood volume increases up to 2 L (30-50% above normal intravascular volume) Arterial Blood Gas – High uterine and placental blood flow demand PaO2* No change (up to 600 mL/min at term) – Increased pelvic venous capacitance PaCO2 Reduced to 28-32 Torr – Protects mother against blood loss during delivery Serum Bicarbonate Reduced to 18-21 mEq/L • Body position alters hemodynamics after 20 weeks – 30% reduction in ejection fraction in supine position *oxygen consumption increases nearly 20% at term but is offset by increase in – Left lateral position improves venous return cardiac output Lapinsky S., Crit Care Med, 2005 Vol. 33, No. 7 1616-1622 Lapinsky S., Crit Care Med, 2005 Vol. 33, No. 7 1616-1622 Fetal Oxygen Delivery Case Report • Determinants: – Maternal arterial oxygen content Diagnosis: – Uterine Blood Flow Post-partum hemorrhage secondary to amniotic fluid embolus leading to a severe – Hgb Concentration coagulopathy (DIC) – Maternal and Fetal Oxygen – Hgb dissociation curves Lapinsky S., Crit Care Med, 2005 Vol. 33, No. 7 1616-1622 Davies et al, Can J Anesth, 1999; 46: 456-459 5

6/1/2013 Obstetric Admissions to the Hemorrhage Intensive Care Unit • Accounts for ~17% of maternal deaths • Causes: 1. Hemorrhage  abnormal placentation , atony, – Abnormal placentation: Acreta (deep in wall), Increta (penetrates muscle), or Percreta (through wall and into another organ) lacerations, retained products of conception, – Uterine atony severe coagulopathy/DIC – Cervical/Vaginal laceration 2. Hypertension  preeclampsia/eclampsia with or without – Coagulopathy/DIC (Amniotic fluid embolus, Abruptio placentae, HELLP ( H emolyisis, E levated L iver enzymes, L ow P latelet HELLP, Retained dead fetus) count) • Treatment: 3. Cardiac disease  valvular diseases, cardiomyopathy, – Supportive with volume resuscitation – Drugs arrhythmias (uterine atony  ergot derivatives, prostaglandin analogues, 4. Respiratory disorders  pulmonary edema (ARDS), oxytocin) asthma (coagulopathy  Factor VIIa) 5. Infection  pyelonephrtis, chorioamnionitis – Extreme cases of hemorrhage: embolization of uterine or iliac Mahutte et al, Obstet and Gynecol, 1999; 94: 263-266 arteries or surgical exploration +/- hysterectomy Lapinsky S., Crit Care Med, 2005 Vol. 33, No. 7 1616-1622 Amniotic Fluid Embolism Amniotic Fluid Embolus • Exceedingly rare • Neonatal outcome poor with mortality rate of • United States registry and United Kingdom registry – US: 46 in 1995 20-25% – UK: 44 in 2005 • Occurs intrapartum or immediate postpartum • Estimated to occur in 1 in 8,000 to 1 in 80,000 period deliveries • NO PROVEN RISK FACTORS • High mortality (60% in older reports; 27% in newer • ONSET CANNOT BE PREDICTED population based study; 37% in 2005 UK registry) Gist et al, Anesthesia and Analgesia, 2009; 108: 1599-1602 Gist et al, Anesthesia and Analgesia, 2009; 108: 1599-1602 6