6096 6096 6097 6097 The US Centers for Disease Control and Prevention (CDC) report on trends in pregnancy-related deaths in the United States from 2014 to 2017 showed that pregnancy-related deaths have increased from 7.2 per 100,000 in 1987 to 17.3 deaths per 100,000 live births in 2017.4 Considerable racial and ethnic disparities in mortality exist, with maternal mortality ranging from 11.6 deaths per 100,000 live births for Hispanic or Latina women to 41.7 deaths per 100,000 live births for non-Hispanic Black women. Deaths due to cardiovascular causes, cerebrovascular accidents, and other medical conditions have increased, while deaths from hemorrhage, hypertensive disorders, embolism, and anesthesia complications have declined. For deaths occurring after a live birth (compared with stillbirth, ectopic pregnancy, or abortion), indirect cardiovascular and medical causes predominate. The most common causes were cardiovascular conditions (15.5% of maternal deaths), infection (12.7%), noncardiovascular medical conditions (12.5%), and cardiomyopathy (11.5%). The other leading causes of maternal death were hemorrhage (10.7%), thrombotic pulmonary or other embolism (9.6%), cerebrovascular accident (8.2%), and preeclampsia/eclampsia (6.6%) (Table 70.2). 6098 6098 6099 6099 The United Kingdom's Centre for Maternal and Child Enquiries audit of maternal mortality for 2015 through 2017 found that their overall maternal mortality rate fell slightly but improvements in care could have made even more of a difference in outcome in 20% of cases.5 Leading causes of death in the United Kingdom and Ireland associated with pregnancy were heart disease (23%), thromboembolism (16%), epilepsy and stroke (13%), other medical conditions (11%), sepsis (10%), mental health conditions (10%), hemorrhage (8%), cancer (4%), and hypertensive disorders (2%). As in the United States, they also found large racial disparities, including a five fold increase in maternal mortality rates among Black women compared to White women. Interestingly, their review from 2009 to 2012 found that of the women who died, 68% died from medical and mental health problems versus only 32% from direct complications of pregnancy.6 The authors emphasized the multifactorial causes of death, the need for multidisciplinary review of all deaths, and the importance of including an anesthesiologist in all investigations. Specific to anesthesiology, they emphasized the value of practicing airway drills, including managing bronchospasm, maintaining postoperative standards in the postanesthesia care unit, and prompt action with good communication between teams during unexpected 6100 6100 6101 6101 6102 6102 6103 6103 6104 6104

Physiologic Variables	Change	Clinical Implications
CARDIOVASCULAR
Blood volume	140%	Hypervolemic
Plasma volume	150%	Dilutional anemia
Heart rate	115 beats/min	Mild tachycardia
Cardiac output	140%	Increased cardiac work to handle increased volume
Systemic resistance	120%	Maintains normal blood pressure with increased cardiac output and volume
Aortocaval compression	Varies	Loss of cardiac preload when supine
RESPIRATORY
Alveolar ventilation	170%	Elevated arterial PO2
Minute ventilation	150% (115% respiratory rate)	PCO2 reduced about 10 mm Hg, mild tachypnea
Functional residual capacity	120%	Rapid desaturation with apnea
Metabolic rate