use left lateral uterus displacement in pregnant patient ACLS

This pregnant patient has experienced a sudden cardiac arrest (SCA). The American Heart Association (AHA) has guidelines for maternal SCA. A maternal code blue should involve a multidisciplinary team including intensivists, obstetricians, anesthesiologists, neonatologists, and obstetrical nursing. It is recommended that the resuscitation is conducted with the uterus displaced off the aortocaval vessels to allow adequate venous return, preload, and cardiac output. This is particularly true in later stages of pregnancy when the uterus is above the umbilicus, as in this case. Positioning should be with manual left lateral displacement of the uterus (choice D is correct). ACLS in pregnant patients has been in the left lateral decubitus position or with the patient tilted to the left with a tiltboard to displace the uterus, but on the basis of randomized trials examining hypotension during cesarean deliveries, manual left lateral displacement of the uterus with the patient in the supine position is recommended because it allows for optimization of chest compressions. Chest compressions are performed at the usual rate and in the usual position on the chest. All electricity energy recommendations are the same, and the same medications should be administered at the same dosages as in the patient who is not pregnant. One caveat is that internal fetal monitor leads should be detached or removed. External monitors should also be detached or removed to prevent interference with compressions or limiting of lateral displacement of the uterus. All IV lines should be placed above the level of the diaphragm to allow for adequate delivery of medications to the central circulation (choice B is incorrect).

In pregnancy, the patient should be assumed to have a difficult airway because of rapid development of hypoxemia because of decreased functional residual capacity and increased oxygen consumption, as well as some component of shunting. The risk of aspiration is increased owing to the enlarging uterus and decreased lower esophageal sphincter tone. There is a narrowing of the upper airway owing to edema related to effects of estrogen, and a smaller endotracheal tube is recommended. There is also a reduction in thoracic compliance. The rate of failed intubation is high in the pregnant population (eight times higher on first pass). Video laryngoscopy and rapid sequence intubation is preferred, and cricoid pressure is no longer clearly recommended.

Special consideration should be given to hypermagnesemia, as magnesium is often used for preterm labor and for preeclampsia and eclampsia. In the case of SCA, if the patient is receiving IV magnesium, as in this case, the magnesium infusion should be discontinued and not be resumed (choice A is incorrect), and reversal agents such as calcium chloride or calcium gluconate should be administered to reverse possible magnesium toxicity.

If there is no return of spontaneous circulation after 4 min at this stage of pregnancy (uterine fundus at or beyond the umbilicus which usually corresponds to >20 weeks’ gestation), the AHA recommends perimortem cesarean delivery (PMCD), also called “resuscitative hysterotomy.” Ideally, this should start at 4 min after arrest, with the baby delivered by 5 min after the arrest (waiting for 20 min as in choice C is incorrect). Alternatively, if the head of the baby is in the perineum, a forceps or vacuum delivery should be performed if it can be done within 5 min of the start of cardiorespiratory collapse. In some cases, open cardiac massage is recommended after 15 min. If the baby is not considered viable, or after cesarean section, extracorporeal life support (ECLS) using veno-arterial extracorporeal membrane oxygenation, or extracorporeal CPR (ECPR), can be considered. In a systemic review of ECLS in pregnancy, ECPR was the indication for ECLS in 16% of cases.

In pregnancy, some of the common causes of SCA can be remembered using the mnemonic A-H: A, anesthetic complications; B, bleeding; C, cardiovascular; D, drugs; E, embolic causes (including venous thromboembolism [VTE], amniotic fluid embolism [AFE], and air embolism); F, fever; G, general, including hypoxia and electrolyte disturbances and the usual h’s and t’s (the five h’s of hypovolemia, hypoxia, hydrogen ion [acidosis], hypoglycemia, and hypothermia and the five t’s of toxins, tamponade [cardiac], tension pneumothorax, thrombosis [pulmonary or cardiac], and trauma); and H, hypertension.

Epidemiologically, some of the common causes of SCA in pregnancy in developed countries include pulmonary embolism; hemorrhage; sepsis; peripartum cardiomyopathy; stroke; preeclampsia and eclampsia; and anesthesia-related complications such as difficult or failed intubation, local anesthetic toxicity, aspiration, and high neuraxial block. Less common causes include amniotic fluid embolism; coronary embolism; air embolism; myocardial infarction and preexisting cardiac disease, such as congenital heart disease; acquired heart disease; anaphylaxis; poisoning; and aortic dissection. The overall prevalence of SCA in pregnancy in the United States is 13.4 events per 100,000 delivery hospitalizations or one in 9,000, and in one large study seven of 10 women survived to hospital discharge. Overall, SCA in pregnancy is associated with high maternal and neonatal mortality rates, but the former are better than that in in-hospital arrests in women who are not pregnant. Risk factors include advanced age, underlying medical conditions, enrollment in Medicare or Medicaid, and/or being of non-Hispanic Black ethnicity. Obesity may also be a risk factor. The AHA reports SCA in one in 12,000 admissions for delivery due to hemorrhage, heart failure, AFE, sepsis, aspiration pneumonia, VTE, preeclampsia and eclampsia, and complications of anesthesia. The most common initial rhythms are PEA in 51%, asystole in 26%, and a shockable rhythm in 12%.1234567

Footnotes

  1. SEEK Questionnaires ↩

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  3. Chu J, Johnston TA, Geoghegan J; Royal College of Obstetricians and Gynaecologists. Maternal collapse in pregnancy and the puerperium: green-top guideline no. 56. BJOG. 2020;127(5):e14-e52. PubMed ↩

  4. Ford ND, DeSisto CL, Galang RR, et al. Cardiac arrest during delivery hospitalization : a cohort study. Ann Intern Med. 2023;176(4):472-479. PubMed ↩

  5. Naoum EE, Chalupka A, Haft J, et al. Extracorporeal life support in pregnancy: a systematic review. J Am Heart Assoc. 2020;9(13):e016072. PubMed ↩

  6. Panchal AR, Bartos JA, Cabañas JG, et al; Adult Basic and Advanced Life Support Writing Group. Part 3: adult basic and advanced life support: 2020 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2020;142(16_suppl_2):S366-S468. PubMed ↩

  7. Zelop CM, Einav S, Mhyre JM, et al; American Heart Association’s Get With the Guidelines-Resuscitation Investigators. Characteristics and outcomes of maternal cardiac arrest: a descriptive analysis of Get with the guidelines data. Resuscitation. 2018;132:17-20. PubMed ↩