Critical Care Obstetrics part 12 potx

Cardiopulmonary Resuscitation in Pregnancy 99 In cases of a witnessed respiratory arrest when the airway is known to be clear but the victim is not breathing, the airway must be protected from aspiration and kept patent, and the BLS/ACLS algorithms begun. Endotracheal intubation by direct laryngos- copy is the preferred method for maintaining airway patency for the gravid arrest victim. Alternative techniques for airway management include endotracheal intubation by light stylet, esophageal tracheal combitube, laryngeal mask airway, and transtracheal ventilation. Tracheal intubation offers advantages of securely protecting the airway, facilitating oxygenation and ventilation, and providing a route for drug administration during a cardiac arrest. In the hospital setting immediate confi rmation of the tracheal tube is typically done using non - physical examination techniques, such as end - tidal (ET) carbon dioxide indicators. The presence of ET CO 2 is a reliable measure of pulmonary perfusion and, therefore, can measure the effi cacy of CPR. Esophageal detector devices may also be used to confi rm tracheal tube placement but false - negative results may be obtained in women in late gestation. False - negative results are due to decreased functional residual capacity (FRC) and tracheal compression in late pregnancy. Consequently, the gold standard for confi rmation in the pregnant women remains repeat direct visualization [23] . Even with advanced airway techniques, airway access and maintenance can be diffi cult in pregnancy due to enlarged breasts and increased pharyngeal edema. Rescuers may fi nd it necessary to use a slightly smaller endotracheal tube than normal [24] . Also, progesterone relaxes the smooth muscle of the lower esophageal sphincter and increases the propensity of the gravida to refl ux and aspirate. Breathing Rescue breathing may occur mouth - to - mouth, mouth - to - nose, mouth - to - mask, bag valve - to - mask, or ultimately by endotracheal intubation. The current guidelines call for a ratio of 2 ventilations to 30 compressions in one - or two - person CPR, pausing for ventilations in the absence of an advanced airway. With a protected airway, the 2005 guidelines call for continuous chest compression with rescue breaths every 6 seconds [25] . In pregnancy, the expanding breast tissue decreases chest wall compliance, making ventilation more diffi cult. The enlarging uterus results in upward displacement of the diaphragm leading to a decrease in the functional residual capacity (FRC) of the lungs. Maternal minute ventilation increases, probably due to a central effect of progesterone. The decrease in FRC combined with the increase in oxygen demand predisposes the pregnant woman to rapid decreases in arterial and venous oxygen tension during periods of decreased ventilation. The chronic increase in ventilation in pregnancy leads to a decline in arterial carbon dioxide tension. The maternal kidney compensates for this respiratory alkalosis by reducing serum bicarbonate concentration. The maternal respiratory alkalosis enhances fetal excretion of carbon dioxide. Hence, increases in maternal carbon dioxide levels promote fetal acidosis. During periods of hypoxia there is also decreased uteroplacental blood fl ow which further promotes fetal acidosis. Thus, the demands of the fetus and normal maternal adaptations to those demands promote rapid maternal hypoxia and acidosis in the presence of hypoventilation. This makes it more diffi cult to resuscitate the mother and ultimately the fetus. Circulation An adequately functioning heart and suffi cient quality and quan- tity of blood are necessary to deliver oxygen to the tissues. In the pulseless patient, external chest compressions provide a means of circulation, as originally described by Kouwenhoven and colleagues in 1960 [26] . The initial belief that the chest compressions cause direct compression of the heart between the sternum and the spine, leading to a rise in ventricular pressure, closure of the mitral and tricuspid valves, forcing blood into the pulmonary artery and aorta, has been disproved. We now understand the primary mechanism of blood movement involves compression - mediated fl uctuations in the intrathoracic pressure that create an arteriovenous pressure gradient peripherally [27] . External chest compressions cause a rise in intrathoracic pressure, which is dis- tributed to all the intrathoracic structures. Competent venous valves prevent transmission of this pressure to extrathoracic veins, whereas the arteries transmit the increased pressure to extrathoracic arteries, creating an artifi cial venous pressure gradient and forward blood fl ow. Werner et al. [28] used echocardiog- raphy to support the notion of the heart as a passive conduit, rather than a pump, by demonstrating that the mitral and tricuspid valves remain open during CPR. With or without an advanced airway, when chest compressions are required, they should be given at a rate of approximately 100/min. Chest compressions should only be interrupted for brief assessments and application of electrical therapy when indicated by the specifi c rhythm and cardiac circulatory effectiveness. The BLS algorithms include the use of automated external defi brillators (AEDs). AED availability and rapid deployment has lead to improved survival. ACLS involves additional electrical and pharmacologic therapy, invasive monitoring, and other therapeutic techniques to correct cardiac arrhythmias, metabolic imbalances, and other causes of cardiac arrest. Defi brillators can be used without signifi cant complications to the fetus in pregnant women [29] . The fetus has a relatively high fi brillation threshold and the electrical current density reaching the fetus is small. Nanson and colleagues evaluated women during and after pregnancy and compared transthoracic impedance values. Because there was no signifi cant difference, the authors concluded that no modifi cations to the recommendations for non - pregnant patients were necessary [30] . Concurrent with establishing cardiac function, resuscitators must assure that arrest victims have adequate quality and quan- tity of blood remaining in the vascular tree for circulation. Although volume administration, which can lead to decreased cerebral and coronary blood fl ow, is generally not recommended during treatment of cardiac arrest, it should be strongly Chapter 7 100 considered in cardiopulmonary arrest related to postpartum hemorrhage or circulatory collapse as seen with amniotic fl uid embolism. Accordingly, early in the resuscitation, resources should be mobilized to obtain blood products to refi ll the vascular tree and manage ongoing hemorrhage. Current data suggest that the optimal product for resuscitations involving massive hemorrhage is whole blood or reconstitutes thereof. However, overzealous fl uid resuscitation, particularly with crystalloid fl uids, before controlling hemorrhage and in the early phases of resuscitation, actually decreases survival [31 – 35] . Factor VII concentrates, now available in many medical centers in the United States, provide an improved means of correcting coagulopathies also common to obstetric hemorrhage. There are now several reports of using recombinant factor VII concentrates in uncon- trolled obstetric hemorrhage [31 – 35] . The reader is referred to Chapter 22 in this text for more information regarding the management of hemorrhage in pregnancy. This stage of the primary and secondary survey of BLS/ACLS should include an assessment of the fetal status and whether or not delivery of the fetus would be of benefi t to mother and/or fetus. Morris and colleagues [36] evaluated neonatal survival following emergency cesarean section in trauma patients presenting to nine Level I trauma centers. The authors suggest adding Doppler fetal heart tone (FHT) assessment to the primary survey along with assessment of maternal circulation. If FHTs are not present, the authors suggest the fetus should otherwise be ignored and treatment directed toward maternal survival. Nonetheless, delivery of the fetus can be considered in the secondary survey if fetal distress is present. More importantly, delivery may be a means of improving effectiveness of maternal CPR efforts even in cases of antecedent fetal death. This has led to a recommenda- tion by some to avoid using precious time for assessment of fetal status when moving forward with cesarean section for maternal benefi t [37] . The e ffect of p regnancy on c ardiopulmonary r esuscitation Pregnancy produces physiologic changes that have profound effects on cardiopulmonary resuscitation. Pregnancy - specifi c physiologic changes and recommended intervention changes to CPR are summarized in Tables 7.5 and 7.6 . There are signifi cant changes in the pulmonary, cardiovascular and renal systems. Some of these changes have been briefl y described above. A more comprehensive description of these changes and their impact on CPR follows. From the circulatory perspective, pregnancy represents a high - fl ow, low - resistance state characterized by a high cardiac output (CO) and low systemic vascular resistance (SVR). Cardiac output increases by 50% of non - pregnant values. The uterus receives up to 30% of cardiac output compared with 2 – 3% in the non - gravid patient. The increase in CO satisfi es the increase in oxygen demands of the growing fetus, the placenta, and the mother. In the latter half of pregnancy, aortocaval compression by the gravid uterus renders resuscitation more diffi cult in the pregnant woman than in her non - pregnant counterpart. The pregnant uterus exerts pressure on the inferior vena cava common iliac vessels, and abdominal aorta. In the supine position, such uterine obstruction may lead to sequestration of up to 30% of circulating blood volume [38] , decreasing venous return, causing supine hypotension, and decreasing effectiveness of thoracic compressions. Furthermore, the enlarged uterus poses an obstruction to forward blood fl ow, particularly when arterial pressure and volume are decreased, as in cardiac arrest. The u se of d rugs for r esuscitation Changes in the gravida woman ’ s response to drugs may also hinder effective resuscitation. Vasopressors used in ACLS, especially alpha - adrenergic or combined alpha and beta agents, are capable of producing uteroplacental vasoconstriction, leading to decreased fetal oxygenation and carbon dioxide exchange. Clinical experience with the pharmacologic agents used in ACLS is limited in pregnancy, particularly when the drugs are used for acute life - threatening situations. In the acute situation, absent or poor maternal cardiac output produces fetal hypoxia and hypercarbia. Thus, despite the potential for uteroplacental vascular vasoconstriction, the benefi ts of these drugs in restoring maternal circulation outweigh their risks. Most of the data concerning fetal effects of these drugs come from chronic use rather than limited dosing in the acute arrest setting. Beginning with the 2000 American Heart Association ACLS guidelines, amiodarone became the drug of choice for treatment of wide - complex tachycardia, stable narrow - complex tachycardia, monomorphic and polymorphic VT, and potentially for shock - refractory VF/VT. Placental transfer occurs with amiodarone at approximately a quarter of the maternal dose. Amiodarone has been labeled a category D drug by the manufac- turer. With chronic use, fetal effects such as growth restriction, hypothyroid goiter, enlarged fontanels, and transient bradycardia in the newborn have all been reported [39] . The drug has been used to successfully treat resistant fetal tachycardia both transplacentally and by direct insertion into the umbilical cord [39] . As with the vasopressors, the concerns raised about chronic use should not negate using amiodarone for maternal resuscitation. Vasopressin was added as a fi rst - line pressor agent in the 2000 CPR guidelines. However, in the 2005 guidelines epinephrine remains the drug of choice as the fi rst - dose pressor agent given in various scenarios given the available data. Nonetheless vasopressin may have a lower adverse affect profi le than epinephrine and the 2005 guidelines allow its use primarily to use primarily when a second pressor dose is required [40,41] . See Figure 7.2 . Some controversy remains about high - dose ( > 1 mg and usually 4 – 5 mg) epinephrine in these scenarios [41 – 44] . At present, the consensus appears to be to use regular - dose epinephrine initially Cardiopulmonary Resuscitation in Pregnancy 101 Table 7.5 Relevant maternal physiologic changes in pregnancy and their effect on CPR [66,70,71] . Measured parameter Direction of change Values in normal pregnancy Effect on CPR Respiratory Pharyngeal edema Increases – May need smaller endotracheal tube, increases diffi culty with intubation and airway control Minute ventilation Increases 50% – Increased development of hypercarbia Oxygen consumption Increases 20% – More rapid development of hypoxia FRC Decreases 20% – More rapid development of hypoxia Arterial PCO 2 Decreases 28 – 32 torr Serum bicarbonate Decreases 18 – 21 mEq/L Decreased acid buffering capability Chest wall compliance Decreases – More diffi cult intubation, increased ventilation pressures Cardiovascular Cardiac output Increases 50% 6.2 ± 1.0 L/min Increases the circulatory demand during CPR Blood volume Increases 30 – 50% – Dilutional anemia with decreased O 2 carrying capacity Heart rate Increases 15 – 20% 83 ± 10 beats/min SVR Decreases 20% 1210 ± 256 dynes/sec/cm − 5 COP Decreases 15% 18 ± 1.5 mmHg Propensity to pulmonary edema PCWP Decreases 7.5 ± 1.8 mmHg Aortocaval compression Increases – Lateral uterine displacement required to maintain venous return and hence cardiac output Hematologic Most clotting factors Increase – Propensity to thrombosis; thromboembolic disease high on differential diagnosis Gastrointestinal Motility Decreases – Increased risk of aspiration, need to protect airway Lower esophageal sphincter tone Decreases – Increased risk of aspiration, need to protect airway Renal Compensated respiratory alkalosis Increases – Modifi cation of target values and increase ventilation required, avoid bicarbinate in CPR Glomerular fi ltration rate Increases – Drug clearance may be modifi ed but consider high dose for prolonged, resistant cardiac arrest [45] . Spohr et al. recently summarized the current data regarding drug therapy for CPR [45] . Adenosine, lidocaine, procainamide, and beta - blockers, also used in the treatment of tachyarrhyth- mias, all appear to be safe in pregnancy [46] . Resuscitators should remember that during pregnancy, the volume of distribution and drug metabolism may vary from non - pregnant norms. Page [47] reviewed the multiple factors contrib- uting to altered therapeutic blood levels of drugs in pregnancy. They include increased intravascular volume, reduced drug protein binding, increased clearance of renally excreted drugs, progesterone - activated increased hepatic metabolism, and altered gastrointestinal absorption due to changes and gastric secretion and gut motility. The agents used in ACLS are recommended in standard doses. However, if the victim does not respond to standard doses, higher doses should be considered to account for the expanded plasma volume of pregnancy. Modifi cations of b asic l ife s upport and a dvanced c ardiac l ife s upport in p regnancy The anatomic and physiologic changes of pregnancy require several modifi cations in ECC (Tables 7.5 & 7.6 ). Most important, to affect an increase in venous return and reduced supine hypotension, the uterus must be displaced to the left. Left lateral displacement can be achieved by: (i) manual displacement of the uterus by a member of the resuscitation team; (ii) positioning of the patient on an operating room table that can be tilted laterally; (iii) positioning a wedge under the right hip; (iv) using a Cardiff resuscitation wedge or (v) using a human wedge [48] . The human wedge kneels on the fl oor with the patient ’ s back placed on the thighs of the human wedge. The human wedge uses one arm to stabilize the patient ’ s shoulder and the other arm to stabilize the pelvis. The human wedge maneuver has the advantage that it may Chapter 7 102 Table 7.6 Primary and secondary ABCD surveys: modifi cations for pregnant women. Reproduced from [72] . ACLS Approach Modifi cations to BLS and ACLS Guidelines Primary ABCD Survey Airway No modifi cations. Breathing No modifi cations. Circulation Place the woman on her left side with her back angled 15 ° to 30 ° back from the left lateral position. Then start chest compressions. or Place a wedge under the woman ’ s right side (so that she tilts toward her left side). or Have one rescuer kneel next to the woman ’ s left side and pull the gravid uterus laterally. This maneuver will relieve pressure on the inferior vena cava. Defi brillation No modifi cations in dose or pad position. Defi brillation shocks transfer no signifi cant current to the fetus. Remove any fetal or uterine monitors before shock delivery. Secondary ABCD Survey Airway Insert an advanced airway early in resuscitation to reduce the risk of regurgitation and aspiration. Airway edema and swelling may reduce the diameter of the trachea. Be prepared to use a tracheal tube that is slightly smaller than the one you would use for a non - pregnant woman of similar size. Monitor for excessive bleeding following insertion of any tube into the oropharynx or nasopharynx. No modifi cations to intubation techniques. A provider experienced in intubation should insert the tracheal tube. Effective preoxygenation is critical because hypoxia can develop quickly. Rapid sequence intubation with continuous cricoid pressure is the preferred technique. Agents for anesthesia or deep sedation should be selected to minimize hypotension. Breathing No modifi cations of confi rmation of tube placement. Note that the esophageal detector device may suggest esophageal placement despite correct tracheal tube placement. The gravid uterus elevates the diaphragm: Patients can develop hypoxemia if either oxygen demand or pulmonary function is compromised. They have less reserve because functional residual capacity and functional residual volume are decreased. Minute ventilation and tidal volume are increased. Tailor ventilatory support to produce effective oxygenation and ventilation. Circulation Follow standard ACLS recommendations for administration of all resuscitation medications. Do not use the femoral vein or other lower extremity sites for venous access. Drugs administered through these sites may not reach the maternal heart unless or until the fetus is delivered. Differential diagnosis and decisions Decide whether to perform emergency hysterotomy. Identify and treat reversible causes of the arrest. Consider causes related to pregnancy and causes considered for all ACLS patients (see the 6 H ’ s and 6 T ’ s, in Part 7.2: “ Management of Cardiac Arrest ” ). be employed without equipment, utilizing an untrained person. Its obvious disadvantage of the wedge is that it must be displaced when defi brillation becomes necessary. The back of an upside down chair may also function as a leaning post to support a woman in a laterally tilted position. The maternal propensity for hypoxia and hypercapnia (which lead to decreases in utero placental perfusion) suggests that the pregnant woman may benefi t from sodium bicarbonate in an arrest situation in order to keep maternal pH greater than 7.10. This idea is hazardous and should be discarded. Sodium bicarbonate crosses the placenta very slowly. Accordingly, with rapid correction of maternal metabolic acidosis, her respiratory com- pensation will cease with normalization of her PCO 2 toward the non - pregnant state. For example, if the maternal PCO 2 increases from 20 to 40 mmHg as a result of bicarbonate administration, fetal PCO 2 will also increase. However, the fetus will not receive the benefi t of the bicarbonate. If the fetal pH was 7.0 before maternal bicarbonate administration, the normalization of maternal pH will be achieved at the expense of increasing the fetal PCO 2 by 20 mmHg, resulting in a reduction in fetal pH to Cardiopulmonary Resuscitation in Pregnancy 103 approximately 6.84. Even in the non - pregnant state, sodium bicarbonate is considered potentially harmful in patients with hypoxic lactic acidosis, such as commonly occurs in non - intu- bated patients undergoing prolonged cardiopulmonary arrest. Carbon dioxide generated in tissues is not well cleared by low blood fl ow [49] . Adequate ventilation and restoration of perfusion are the mainstays of control of acid – base balance during cardiac arrest. The buffering of blood with bicarbonate does not benefi t the patient [50] . Thrombolytic t herapy Unfractionated and low molecular weight heparins have been used extensively during pregnancy. In cases of acute cardiopulmonary thrombosis, therapy with these agents has proven helpful in both non - pregnant and pregnant patients. There is much less data regarding the use of other thrombolytic therapies during pregnancy including recombinant tissue plasminogen activators (TPA). Generally, pregnancy is considered a contraindication to TPA therapy but there are several case reports of successful use during pregnancy [51 – 53] . The use of such agents increases the risk of hemorrhage, particularly in the scenario when operative delivery has or is likely to occur. Nonetheless, the use of these agents should not be completely excluded when alternative therapies have been unsuccessful. Complications and a ftercare of c ardiopulmonary r esuscitation d uring p regnancy Unfortunately, CPR is rarely effective in restoring spontaneous circulation and permitting neurologically intact recovery to hospital discharge. Successful resuscitation is reported in 6 – 15% of patients suffering in - hospital cardiac arrest [54,55] . In pregnancy, survival may be even less likely given the maternal physiologic changes that predispose her to rapid hypoxia and complicated resuscitative efforts. Fortunately, the paucity of underlying disease may improve the likelihood of success. For survivors, cardiopulmonary resuscitation may impose secondary complications on both mother and fetus. Ongoing sup- portive and therapeutic care will be necessary, paying careful attention to common areas of injury and ongoing risk. Care is best accomplished by a multidisciplinary team. Neonatal and maternal care providers should assess for injuries. Maternal injuries may include: (i) fractures of ribs and sternum; (ii) hemotho- rax and hemopericardium; (iii) rupture of internal organs (especially the spleen and uterus); and (iv) lacerations of organs (most notably the liver). Damaging effects to the fetus consist of central nervous toxicity from medications and reduced uteroplacental perfusion with possible fetal hypoxemia and acidemia. Fetal monitoring may be used to assess ongoing fetal status; however, maternal resuscitation should be the primary goal. Perimortem c esarean d elivery Historically, perimortem cesarean delivery (PMCD) was a widely accepted practice. In fact, the term cesarean developed from the Roman period (715 – 763 BC) when PMCD was practiced under the law of Caesar ( lex Cesare ), not for maternal or fetal benefi t, rather to allow woman and children to be buried separately for religious ritual [56] . In ancient Greek mythology the fi rst cesarean section was performed by Apollo, on his wife Coronois, as she was being burned on a funeral pyre. Their son, Asclepius, is said to be the demigod of medicine and healing. The Staff of Asclepius, a rod entwined with a single serpent, has become the symbol for physicians across the globe. The fi rst documented case of maternal survival from a PMCD took place in Switzerland, when a farmer named Jacob Nufer performed a cesarean delivery on his own wife [57] . Since then, over 250 reports of maternal survival from PMCD have been described. Recognition that the gravid uterus may prevent proper CPR techniques by restoring adequate cardiac output, has led many to theorize that immediate PMCD may assist in maternal resuscitation. The theory is that the low - resistance, high - volume uteroplacental unit sequesters blood and hinders effective CPR. Delivery leads to a decrease in aortocaval obstruction, and increase in effectiveness of compressions, and an increase in maternal cardiac output. In a recent review by Katz et al., 12 of 22 case reports showed a sudden and often dramatic improve- ment in pulseless gravidas following uterine evacuation [58] . When considering PMCD, several factors need to be addressed. Clearly, the timing of the operation is critical for infant survival. Survival appears to be inversely proportional to the time between the mother ’ s cardiac arrest and her delivery. In 1986, Katz et al. introduced the idea of the “ 4 - minute rule ” for PMCD, basing their recommendations on the idea that maternal neurologic injury would commence 6 minutes after the cessation of cerebral perfusion [59] . If delivery is accomplished within 5 minutes of maternal cardiac arrest, intact neurologic survival is likely [15,59] . Beyond 15 minutes, neonatal death or impaired survival is generally seen. Primate studies confi rm brain damage in utero with as little as 6 minutes of complete asphyxia and severe cellular damage occurring by 8 minutes [60] . Nonetheless scattered reports describe infant survival at longer intervals following arrest, implying that cesarean delivery should be performed post arrest if signs of fetal life are still present [61,62] . In light of the evolving timing of the limits of fetal viability, one group of authors attempted to develop an algorithm to assist clinicians in determining when and who would benefi t from a postmortem cesarean section [36] . The “ potentially salvageable ” infant was defi ned as an estimated gestational age of at least 26 weeks with the confi rmation of fetal cardiac activity by Doppler ultrasound. In this group, 75% of the infants survived. The authors postulated that 60% of the infant deaths may have been avoided by earlier recognition of fetal distress and earlier cesarean delivery. With evolving technology, determination of what Chapter 7 104 gestational age defi nes fetal viability will be left to the discretion of the delivering physician and the resources available for neonatal resuscitation. To date, we have not identifi ed any lawsuits brought against physicians for the wrongful performance of a PMCD. The 4 - minute limit to initiate delivery, as advocated by Katz and colleagues [58,59] and the American College of Obstetricians and Gynecologists is derived from the theoretical physiologic advantages for resuscitating the mother, as well as from extrapo- lation of data on infant survival. While such data suggests an ideal arrest - to - delivery interval, in actual practice these goals are rarely achieved. It must be emphasized that no data exist to prospec- tively document actual maternal benefi ts of perimortem cesarean section. There are many anecdotal examples of improved maternal response to resuscitation after perimortem cesarean. However, maternal death remains the most likely outcome regardless of arrest - to - delivery interval. None - the - less, in light of both the anecdotal experiences suggesting benefi t to mother and fetus, and the dismal outcomes without intervention, we support the concept of the 4 - minute rule based on the currently available evidence. In the setting of perimortem cesarean section performed for the likely salvageable fetus, the staff should be well versed in the techniques of neonatal resuscitation as these infants are likely to suffer from respiratory and circulatory depression at birth. Women with chronic illnesses are less likely to have a normal surviving infant by perimortem cesarean section, compared to previously healthy women who suffer cardiac arrest following an acute obstetric event. The n eurologically i mpaired p atient f ollowing r esuscitation On the rare occasion when a patient is successfully resuscitated but left brain dead and a cesarean section has not been performed, several medical, social, ethical and legal dilemmas follow. In most circumstances, advance directives are not available to guide the physician in the decision - making process. A decision must be made, based on gestational age, family wishes (or medical power of attorney), and available resources, on whether to extend the maternal life for fetal benefi t. To arrive at a decision involving the prolongation of pregnancy in a brain - dead pregnant patient, the physician must be guided by basic ethical and legal principles. If an advance directive is available and deemed lawful, it must be interpreted within the context of the situation and with the patient ’ s values in mind. If a durable power of attorney or next of kin are not available, or if there is confl ict within the family, then legal counsel is recommended. Keep in mind that the decision to prolong maternal life for the benefi t of the fetus must fi rst be consistent with the values of the patient as determined by the next of kin. Historically, gestational age at the timing of the event was often cited as the most important variable, with the assumption that prolongation of a pregnancy was rarely successful beyond 2 – 4 weeks, and thus should only be considered in the gravid women beyond 24 weeks gestational age [63] . However, more recent cases have demonstrated that pregnancy can be prolonged for as long as 204 days following severe neurologic injury, and as early as 15 weeks gestation in a brain - dead patient [64,65] . Therefore, the more relevant questions for the physician and family are if prolongation of the pregnancy is what the patient would have wanted and if so, when is the appropriate time for delivery to optimize the health of the neonate? If the decision is made to prolong the pregnancy, a unique set of medical complications must also be addressed in anticipation of expected physiologic changes following brain death. Discussion of the somatic support of a brain dead gravida is beyond the scope of this chapter, but is covered comprehensively in a review by Mallampalli and colleagues [66] . Case p resentation A 22 - year - old primigravida was admitted to the hospital for mild pre - eclampsia and preterm contractions at 32 weeks. Her pregnancy was remarkable for a 12 - year history of insulin - dependent diabetes. Her blood sugar control was reasonable on an insulin pump. She had no overt consequences of microvascular injury. She was given pneumatic compression stockings for use while in bed. The 2 - week admission was remarkable for episodes of short- ness of breath associated with ambulation and with pneumatic compression stocking use. She was evaluated clinically. Chest X - ray, pulse oximetry, and an ECG were performed. Throm- boembolic disease was entertained but ultimately considered unlikely. Because of the discomfort with the compression stockings they were discontinued and she was started on thrombopro- phylactic doses of heparin. She labored spontaneously in the 36th week but had arrest of dilatation at 8 cm. After unsuccessful oxytocin labor stimulation, she was taken for cesarean section on a weekend morning. The delivery occurred using the labor epidural from a recumbent position with a left lateral tilt. Just as the rectus fascia was incised, she suddenly expressed great anxiety, attempted to sit up and then collapsed unresponsive. Cardiac monitoring initially showed bradycardia to the 40s and then became erratic. There was no palpable pulse. Within the fi rst 2 minutes of the event, a hospital “ code blue ” was initiated, the baby was quickly delivered, endotracheal intubation was attempted and chest compressions begun. The initial intubation was unsuccessful and bag/mask ventilation was performed. Two 1 - mg doses of epinephrine followed by 1 mg of atropine were given intravenously without response. Lidocaine and calcium were given and a second attempt at endotracheal intubation was successful within 4 minutes into the resuscitation. The cardiac monitors showed only a fl at line tracing. External cardiac monitors were disconnected. Cardioversions with 200, 360 and 360 J were attempted with intermittent CPR and rhythm monitoring without a positive response. Four mg of epinephrine was given intravenously; there was no response. Cardiopulmonary Resuscitation in Pregnancy 105 Eight minutes into the resuscitation, the potential etiologies of the arrest were reviewed. Given the absence of an apparent coagu- lopathy, anaphalactoid syndrome of pregnancy was considered unlikely. However, the history of previous events, now more sus- picious for possible thromboembolic phenomenon, put a large pulmonary embolism at the top of the differential diagnoses. The pulseless electrical activity (PEA) identifi ed earlier in the resuscitation supported this possibility. Left lateral thoracotomy and pericardotomy were performed and open cardiac massage was initiated. Within 30 seconds a palpable beat was noted with subsequent beats following in increasingly rapid succession. By 12 – 15 minutes into the resuscitation the patient had a sustained rhythm and a blood pressure of 70/40. Bilateral chest tubes were placed. She was given 80 mg/kg of heparin. An hour into the resuscitation a portable pulmonary arteriogram demonstrated bilateral distal fi lling defects in the pulmonary vasculature. Ultimately, to maintain an adequate blood pressure, the patient was given multiple 4 - mg doses of epinephrine. She needed levoephedrin, dopamine and neosyn- ephrin drips and required cardiac massage on two subsequent occasions to maintain an adequate cardiac output. She received a total of 10 units of packed red blood cells during the fi rst 4 hours of the resuscitation and 2 units of FFP. Crystalloid fl uids were limited to 800 mL during the fi rst 3 hours. Three hours into the resuscitation her pupils were fi xed and dilated. There was no response to stimulation despite the fact that no pharmacologic sedation had been given. The patient was warmed, the wounds closed and she was transferred to the ICU. Within 18 hours of the arrest she was appropriately responsive. She was extubated within 72 hours. She was discharged from the hospital on post arrest day 40 with moderate lower extremity spasticity and short - term memory loss but otherwise neurologically intact. Her cardiac output at discharge was 25%. Over the course of 2 years her cardiac and neurologic function completely normalized. The baby has done well. Summary Sudden cardiac arrest is uncommon in pregnancy and is usually catastrophic when it occurs. Because SCA arrest in pregnancy is a rare event, medical facilities and personnel must maintain com- petency by training and practice. While successful resuscitation is uncommon, early aggressive resuscitation by well - trained and skilled attendants improves the likelihood of survival. The latest guidelines for CPR by the American Heart Association make several recommendations for change from the previous algorithms. Pregnancy necessitates several modifi cations to standard CPR that include displacement of the uterus off the vena cava to facilitate venous return. Modifi cations to pharmacologic or electrical therapy are usually not necessary. Immediate action is critical for both mother and baby. In pregnant and non - pregnant individuals there is a window of opportunity in the fi rst 5 minutes after the arrest. This short window of time includes decisions about and performance of emergency cesarean section if that course is elected. Urgent cesarean delivery in SCA victims may be of benefi t to both mother and baby. Precisely because SCA is an uncommon event on the labor and delivery unit, it is often unexpected. Thus, training and drilling for such events should be a priority in order to maintain a state of alert and readiness by hospital personnel. We concur with Morris and colleagues [67] that the best opportunity for good outcome occurs when inertia can be avoided. We must avoid (i) the inertia of fear that proven procedures and medications in non - pregnant patients will adversely affect the fetus, (ii) the inertia of indecision about emergent surgical delivery, (iii) the inertia of hopelessness for the desperately ill mother, delivered or undelivered, and (iv) the peculiarly American condition of medi- colegal dystocia. References 1 Zheng ZJ et al. Sudden cardiac death in the United States, 1989 to 1998 . Circulation 2001 ; 104 : 2158 – 2163 . 2 Thel MC , O ’ Connor CM . Cardiopulmonary resuscitation: historical perspective to recent investigations . Am Heart J 1999 ; 137 : 39 – 48 . 3 Cobb LA et al. Changing incidence of out - of - hospital ventricular fi brillation, 1980 – 2000 . JAMA 2002 ; 288 : 3008 – 3013 . 4 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care . Circulation 2005 ; 112 ( 24 Suppl ): IV1 – 203 . 5 Dildy GA , Clark SL . Cardiac arrest during pregnancy . 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Dildy. © 2010 Blackwell Publishing Ltd. 8 Neonatal Resuscitation Christian Con Yost & Ron Bloom Department of Neonatology, University of Utah Health Sciences, Salt Lake City, UT, USA Introduction Under normal circumstances, the transition from womb to world is a series of dramatic and rapid physiologic changes leading to the birth of an infant prepared to continue the processes of growth and development. The goal of delivering a healthy infant intact ready to continue normal development is, unfortunately, not always possible. Pregnancies and/or deliveries complicated by common and uncommon conditions, discussed throughout this text, are at increased risk of failing to successfully make the transition to extrauterine life. Modern diagnostic tools often, but not always, allow for anticipation of infants at risk of not making a successful transition, and, thus, permit the perinatal team to plan for neonatal resuscitation and/or medically necessary interven- tions. However, more acute and often unanticipated conditions such as a sudden prolapsed cord, an abruption or a previously unrecognized congenital anomaly may result in the need for an unanticipated, but nevertheless, skillful resuscitation. At birth, neonatal resuscitation may be necessary. However, because it is not possible to predict every infant who may require resuscitation, the ability to conduct an effective resuscitation is an integral part of the considerations and planning for any delivery. Regardless of level of care, a trained and experienced team, readily available, is an integral part of perinatal care. These teams must be provided with appropriate and well functioning equipment needed to resuscitate a newborn [1] . Skilled and experienced personnel with the right equipment can usually intervene successfully on a compromised infant ’ s behalf. The approach to neonatal resuscitation has continually changed since the late 1980s when the teaching of neonatal resuscitation became commonplace. Over the last 20 years, we have reconsid- ered our approach to resuscitation and have questioned some of our previous assumptions. We are now considering approaches to assisted ventilation and the use of oxygen from a whole new perspective. This chapter will not address the details of exactly how to perform a resuscitation. This is very well taught in the Neonatal Resuscitation Program of the American Academy of Pediatrics/ American Heart Association [2] and the details exceed the bounds of this chapter. What we will discuss are some of the new ideas, approaches and principles as well as some basic elements of neonatal resuscitation. In this context, we will discuss the role of continuous positive airway pressure versus intermittent manda- tory ventilation. We will also discuss the growing dialogue regarding the use of oxygen in the resuscitative process. Elements of b irth d epression Causes of b irth d epression While all deliveries involve a complex physiologic transition at birth, infants of those mothers cared for by the high - risk obstetric team, especially if premature, are at a greater risk of birth depression. The newborn infant may be depressed at birth through a variety of mechanisms, some of which are unrelated to asphyxia. Birth depression requiring resuscitation of a neonate cannot always be predicted, but at least among infants born of high - risk pregnancies, it should be expected. Maternal or placental conditions can result in birth depression. For example, diminished uterine blood fl ow may result from maternal hypotension, eclampsia, regional anesthesia or uterine contractions. Placental abnormalities such as an abruption, edema, or infl ammatory changes may reduce placental gas exchange. Fetoplacental blood fl ow may also be compromised due to sustained and unrelieved cord compression from a nuchal or prolapsed umbilical cord. Compromising conditions or events may also be primarily fetal in origin. These include drug - induced central nervous system (CNS) depression, CNS anomalies, spinal cord injury, mechani- cal airway obstruction, pulmonary immaturity, congenital anomalies and infection. All of these events or conditions, maternal and . Cardiopulmonary Resuscitation and Emergency Cardiovascular Care . Circulation 2005 ; 112 ( 24 Suppl ): p. IV152 . 108 Critical Care Obstetrics, 5th edition. Edited by M. Belfort, G Cardiopulmonary resuscitation in intensive care unit and non - intensive care unit patients. Immediate and long - term survival . Arch Intern Med 1995 ; 155 : 127 7 – 128 0 . 56 Ritter JW . Postmortem. therapeutic care will be necessary, paying careful attention to common areas of injury and ongoing risk. Care is best accomplished by a multidisciplinary team. Neonatal and maternal care providers