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Air Medical Transport of a Patient with Placenta Accreta
CASE STUDY
Air Medical Transport of a Patient with Placenta Accreta Brian G. Cornelius, RN, BSN, CCRN, EMT-P, and Angela P. Cornelius, MD
Abstract Air medical transport of high-risk obstetric and postpartum patients accounts for a low number of flights nationwide. Although reflecting a low percentage, they pose potential for increased challenge because of high acuity and increased liability. High-risk obstetrical flight crew education is typically focused on care of the gestational mother and newborn infant, with less time spent on postpartum complications. While uncommon, placenta accreta is one complication that poses a significant mortality risk for postpartum patients.
Introduction Air medical transport of high-risk obstetric and postpartum patients accounts for a low percentage of flights nationwide. Simultaneously, crews may encounter an increased clinical challenge as a result of elevated patient acuity and degree of potential liability. Typically, the focus of flight crew education is on care of the gestational mother and newborn infant, with little training concerning postpartum complications. Although uncommon, placenta accreta poses a significant mortality risk for this patient population.
Case Study Air medical transport was requested for a 37-year-old woman, gravida-9, para-9, from a rural facility to a tertiary care center. The patient delivered a healthy, 39-week gestational-age boy by cesarean section without difficulty. After removal of the placenta, the physician was unable to control the hemorrhage with oxytocin (Pitocin), methylergonovine (Methergine), and bimanual uterine massage. The patient subsequently was intubated, and aggressive blood product resuscitation was initiated. She remained hypotensive and was started on a dopamine drip titrated to 20 mcg/kg/min. When the flight crew arrived, the patient had an estimated blood loss of 4000 mL, had received 8 units of red blood cells
Halo Flight, Corpus Christi, TX Address for correspondence: Brian G. Cornelius, RN, BSN, CCRN, EMT-P, Halo Flight, 1843 FM 665, Corpus Christi, TX 78415; [email protected] 1067-991X/$36.00 Copyright 2010 by Air Medical Journal Associates doi:10.1016/j.amj.2010.02.008 124
(RBCs) and 10 L of warm saline, and remained on dopamine with a blood pressure of 60/20, pulse of 140, and SpO2 98%. The patient remained under general anesthesia, and the physician obtained operative hemorrhage control through ligation of the uterine arteries. During abdominal exploration, the patient was diagnosed with placenta accreta. The flight crew started a norepinephrine (Levophed) infusion and administered an additional 2 units of RBCs, 2 units of fresh frozen plasma (FFP), and a 10 pack of platelets. The patient’s blood pressure favorably improved to 85/40, and heart rate decreased to 120 beats/min. During transport, she received an additional 2 units of RBCs and 2000 mL of saline and was maintained on the Levophed and dopamine drips. Her mentation also increased, requiring midazolam (Versed), fentanyl (Sublimaze), and vecuronium (Norcuron). Upon arrival at the receiving facility, she was taken directly to the operative suite, where a hysterectomy was performed, during which additional blood products were administered.
Discussion Postpartum hemorrhage, defined as a blood loss of greater than 500 mL, occurs in up to 18% of deliveries and is the leading cause of maternal morbidity in developed countries.1 Although risk factors and preventive strategies are clearly documented, not all cases are expected or avoidable. Uterine atony is responsible for most cases and can be managed with uterine massage in conjunction with oxytocin, prostaglandins, and ergot alkaloids. Retained placenta is a less common cause and requires examination of the placenta, exploration of the uterine cavity, and manual removal of retained tissue. Rarely, an invasive placenta causes postpartum hemorrhage and may require surgical management. Coagulopathies require clotting factor replacement for the identified deficiency. Early recognition, systematic evaluation and treatment, and prompt fluid resuscitation help minimize the potentially serious outcomes associated with postpartum hemorrhage. Risk factors for postpartum hemorrhage include a prolonged third stage of labor, multiple delivery, episiotomy, fetal macrosomia, and history of postpartum hemorrhage.2 However, it may also occur in women without apparent risk factors, so providers must be prepared to manage this condition at every delivery.3 Re-examination of the patient’s vital signs and vaginal flow before leaving the delivery area may help detect slow, steady bleeding. Air Medical Journal 29:3
While collectively termed placenta accrete, three variants of the condition are recognized. In the most common form, accreta, the placenta is attached directly to the muscle of the uterine wall. This variant accounts for approximately 75%-78% of all cases. In another 17% of patients, the placenta extends into the uterine muscle and is termed placenta increta. In the remaining 5%-7%, the placenta extends through the entire wall of the uterus and is termed placenta percreta. The reported incidence of placenta accreta averages approximately 1 in 7,000. Of note, this incidence may be increasing because of an increased number of women with previous cesarean sections. In placenta accreta, the abnormally firm attachment of the placenta to the uterine wall prevents the placenta from separating normally after delivery. The retained placenta interferes with the uterine contraction necessary to control bleeding after delivery. Severe bleeding and the surgical procedures performed in attempts to control it are the major sources of maternal morbidity and mortality. Blood transfusions are required in more than 50% of patients with placenta accreta. The principal newborn complication of this condition is prematurity. Although earlier reports suggested an associated increase in perinatal mortality, recent studies do not confirm this.4 Preterm birth complicates nearly two-thirds of cases, with an average gestational age at delivery of 34-35 weeks. Several risk factors for placenta accreta have been identified.5 Among these, the most important appears to be placenta previa. Placenta accreta complicates approximately 10% of all cases of placenta previa, with an incidence that appears to correlate with the number of previous cesarean sections. In the absence of placenta previa, accreta is rare. Maternal age greater than 35 and placental location overlying the previous uterine scar also increase the risk of accreta. Other reported risk factors include multiple previous pregnancies, previous uterine surgery, and previous dilation and curettage. Placenta accreta should be suspected in all women with placenta previa. In the majority of cases, placenta accreta remains asymptomatic until delivery. Although bleeding prior to labor is not uncommon, it is more likely related to placenta previa than to placenta accreta. MRI, combined with ultrasound, has a sensitivity of 100% in identifying placenta accrete.6 Unfortunately, most cases of placenta accreta are encountered without warning in women who are not prepared for the possibility of hysterectomy. Control of potentially life-threatening hemorrhage is the first priority; however, the patient’s desire for future fertility must be considered if at all possible. Historically, control of bleeding has been achieved by hysterectomy. Initial conservative management of placenta accreta may include curettage and/or over-sewing of the placental bed and occluding the blood vessels that supply the pelvis. Reported success rates of these maneuvers vary greatly. Another approach is to use fluoroscopy to inject gelatin sponge particles or spring coils into the blood vessels supplying the uterus.7 As noted previously, this technique is not feasible in most emergent situations but is becoming May-June 2010
increasingly more prevalent within a higher number of interventional radiology suites. Care during transport is focused on achieving hemodynamic stability and rapid transfer to a comprehensive treatment facility. The classic scenario for involvement of air medical transport is an unsuspected placenta accreta that is found during cesarean section at an outlying facility that lacks additional surgical or interventional radiologic resources. The facility rapidly exhausts available resources and requests transfer to a facility with more extensive resources. In this scenario, the limited availability of blood products at outlying facilities may necessitate the transport team bringing additional products with them on the flight. If blood products are not available, the administration of colloids such as hetastarch (Hespan) or albumin may be beneficial. If the patient remains hypoperfused after the administration of blood products, vasopressors may be necessary. As the patient in the case presentation illustrates, the use of a single pressor may not be adequate. Transport teams must ensure they have additional vasopressors available. It may also be necessary to use additional medications from the referring facility. Given the nature of hypovolemic shock, commonly used vasopressors include dopamine (in high doses 10-20 mcg/kg/min), norepinephrine, and neosynephrine.8 Caution must be exercised to avoid relative hypertension, as this may decrease clot formation and increase hemorrhage. In addition, proactive and aggressive airway management should be considered because of the altered mentation that may accompany hypoperfusion. Caution should be used in the selection of induction agents because of the hypotension that accompanies several commonly used medications. Given the necessity for large volumes of blood products, calcium levels should be monitored, as replacement will likely be necessary. During care and subsequent transport, several monitoring parameters should be considered. As with any bleeding patient requiring massive blood transfusion, the goal of 1:1 replacement should be followed.9 This may also require platelets and FFP; cryoprecipitate may also be considered. Given the difficulty of estimating blood loss, the use of measured hemoglobin may be useful. Obtained in conjunction with an arterial blood gas, the base deficit may also aid in volume replacement. Additionally, coagulation studies should be completed as a result of the high potential for disseminated intravascular coagulation. Transport should not be delayed awaiting return of laboratory results. In lieu of rapidly available laboratory measurements, the heart rate, blood pressure, and, if available, central venous pressure and urine output may be used. Desirable treatment responses include increased mentation, improved capillary refill, central venous pressure greater than or equal to 8mmHg, mean arterial blood pressure greater than 80 mmHg, and urinary output 30-60 mL/hr or greater. As this case demonstrates, a complex obstetrical patient may be every bit as complicated as more commonly seen 125
trauma or medical patients. However, given the lower case frequency and high potential for mortality, it may be more stressful for transport crews. As the number of cesarean sections increases, the likelihood of transporting a patient with placenta accreta also increases. Additional education at both the local and industry level will ultimately prove beneficial toward successful treatment of these patients.
References 1. The Prevention and Management of Postpartum Haemorrhage: Report of Technical Working Group, Geneva 3-6 July 1989. Geneva: World Health Organization, 1990. 2. Stones RW, Paterson CM, Saunders NJ. Risk factors for major obstetric haemorrhage. Eur J Obstet Gynecol Reprod Biol 1993;48:15-8. 3. Sherman SJ, Greenspoon JS, Nelson JM, Paul RH. Identifying the obstetric patient at high risk of multiple-unit blood transfusions. J Reprod Med 1992;37:649-52. 4. Miller DA. Obstetric hemorrhage. December 18, 2002. Available at http://www.obfocus.com/high-risk/bleeding/hemorrhagepa.htm. Accessed March 15, 2010. 5. Clark SL, Koonings PP, Phelan JP. Placenta previa/accreta and prior cesarean section. Obstet Gynecol. 1985;66:89-92. 6. Levine D, et al. Placenta accreta: evaluation with color Doppler US, power Doppler US, and MRI imaging. Radiology. 1997;205:773-776. 7. Descargues G, Douvrin F, Degre S, et al. Abnormal placentation and selective embolization of the uterine arteries. Eur J Obstet Gynecol Reprod Biol. 2001;99(1):47-52. 8. Wilson M, Davis DP, Coimbra R. Diagnosis and monitoring of hemorrhagic shock during the initial resuscitation of multiple trauma patients: a review. J Emerg Med. 2003;24(4):413-22. 9. Ketchum L, Hess JR, Hiippala S. Indications for Early Fresh Frozen Plasma, Cryoprecipitate and Platelet Transfusion in Trauma. J Trauma 2005:60:6:S51-S58.
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Air Medical Journal 29:3
Air Medical Transport of a Patient with Placenta Accreta Brian G. Cornelius, RN, BSN, CCRN, EMT-P, and Angela P. Cornelius, MD
Abstract Air medical transport of high-risk obstetric and postpartum patients accounts for a low number of flights nationwide. Although reflecting a low percentage, they pose potential for increased challenge because of high acuity and increased liability. High-risk obstetrical flight crew education is typically focused on care of the gestational mother and newborn infant, with less time spent on postpartum complications. While uncommon, placenta accreta is one complication that poses a significant mortality risk for postpartum patients.
Introduction Air medical transport of high-risk obstetric and postpartum patients accounts for a low percentage of flights nationwide. Simultaneously, crews may encounter an increased clinical challenge as a result of elevated patient acuity and degree of potential liability. Typically, the focus of flight crew education is on care of the gestational mother and newborn infant, with little training concerning postpartum complications. Although uncommon, placenta accreta poses a significant mortality risk for this patient population.
Case Study Air medical transport was requested for a 37-year-old woman, gravida-9, para-9, from a rural facility to a tertiary care center. The patient delivered a healthy, 39-week gestational-age boy by cesarean section without difficulty. After removal of the placenta, the physician was unable to control the hemorrhage with oxytocin (Pitocin), methylergonovine (Methergine), and bimanual uterine massage. The patient subsequently was intubated, and aggressive blood product resuscitation was initiated. She remained hypotensive and was started on a dopamine drip titrated to 20 mcg/kg/min. When the flight crew arrived, the patient had an estimated blood loss of 4000 mL, had received 8 units of red blood cells
Halo Flight, Corpus Christi, TX Address for correspondence: Brian G. Cornelius, RN, BSN, CCRN, EMT-P, Halo Flight, 1843 FM 665, Corpus Christi, TX 78415; [email protected] 1067-991X/$36.00 Copyright 2010 by Air Medical Journal Associates doi:10.1016/j.amj.2010.02.008 124
(RBCs) and 10 L of warm saline, and remained on dopamine with a blood pressure of 60/20, pulse of 140, and SpO2 98%. The patient remained under general anesthesia, and the physician obtained operative hemorrhage control through ligation of the uterine arteries. During abdominal exploration, the patient was diagnosed with placenta accreta. The flight crew started a norepinephrine (Levophed) infusion and administered an additional 2 units of RBCs, 2 units of fresh frozen plasma (FFP), and a 10 pack of platelets. The patient’s blood pressure favorably improved to 85/40, and heart rate decreased to 120 beats/min. During transport, she received an additional 2 units of RBCs and 2000 mL of saline and was maintained on the Levophed and dopamine drips. Her mentation also increased, requiring midazolam (Versed), fentanyl (Sublimaze), and vecuronium (Norcuron). Upon arrival at the receiving facility, she was taken directly to the operative suite, where a hysterectomy was performed, during which additional blood products were administered.
Discussion Postpartum hemorrhage, defined as a blood loss of greater than 500 mL, occurs in up to 18% of deliveries and is the leading cause of maternal morbidity in developed countries.1 Although risk factors and preventive strategies are clearly documented, not all cases are expected or avoidable. Uterine atony is responsible for most cases and can be managed with uterine massage in conjunction with oxytocin, prostaglandins, and ergot alkaloids. Retained placenta is a less common cause and requires examination of the placenta, exploration of the uterine cavity, and manual removal of retained tissue. Rarely, an invasive placenta causes postpartum hemorrhage and may require surgical management. Coagulopathies require clotting factor replacement for the identified deficiency. Early recognition, systematic evaluation and treatment, and prompt fluid resuscitation help minimize the potentially serious outcomes associated with postpartum hemorrhage. Risk factors for postpartum hemorrhage include a prolonged third stage of labor, multiple delivery, episiotomy, fetal macrosomia, and history of postpartum hemorrhage.2 However, it may also occur in women without apparent risk factors, so providers must be prepared to manage this condition at every delivery.3 Re-examination of the patient’s vital signs and vaginal flow before leaving the delivery area may help detect slow, steady bleeding. Air Medical Journal 29:3
While collectively termed placenta accrete, three variants of the condition are recognized. In the most common form, accreta, the placenta is attached directly to the muscle of the uterine wall. This variant accounts for approximately 75%-78% of all cases. In another 17% of patients, the placenta extends into the uterine muscle and is termed placenta increta. In the remaining 5%-7%, the placenta extends through the entire wall of the uterus and is termed placenta percreta. The reported incidence of placenta accreta averages approximately 1 in 7,000. Of note, this incidence may be increasing because of an increased number of women with previous cesarean sections. In placenta accreta, the abnormally firm attachment of the placenta to the uterine wall prevents the placenta from separating normally after delivery. The retained placenta interferes with the uterine contraction necessary to control bleeding after delivery. Severe bleeding and the surgical procedures performed in attempts to control it are the major sources of maternal morbidity and mortality. Blood transfusions are required in more than 50% of patients with placenta accreta. The principal newborn complication of this condition is prematurity. Although earlier reports suggested an associated increase in perinatal mortality, recent studies do not confirm this.4 Preterm birth complicates nearly two-thirds of cases, with an average gestational age at delivery of 34-35 weeks. Several risk factors for placenta accreta have been identified.5 Among these, the most important appears to be placenta previa. Placenta accreta complicates approximately 10% of all cases of placenta previa, with an incidence that appears to correlate with the number of previous cesarean sections. In the absence of placenta previa, accreta is rare. Maternal age greater than 35 and placental location overlying the previous uterine scar also increase the risk of accreta. Other reported risk factors include multiple previous pregnancies, previous uterine surgery, and previous dilation and curettage. Placenta accreta should be suspected in all women with placenta previa. In the majority of cases, placenta accreta remains asymptomatic until delivery. Although bleeding prior to labor is not uncommon, it is more likely related to placenta previa than to placenta accreta. MRI, combined with ultrasound, has a sensitivity of 100% in identifying placenta accrete.6 Unfortunately, most cases of placenta accreta are encountered without warning in women who are not prepared for the possibility of hysterectomy. Control of potentially life-threatening hemorrhage is the first priority; however, the patient’s desire for future fertility must be considered if at all possible. Historically, control of bleeding has been achieved by hysterectomy. Initial conservative management of placenta accreta may include curettage and/or over-sewing of the placental bed and occluding the blood vessels that supply the pelvis. Reported success rates of these maneuvers vary greatly. Another approach is to use fluoroscopy to inject gelatin sponge particles or spring coils into the blood vessels supplying the uterus.7 As noted previously, this technique is not feasible in most emergent situations but is becoming May-June 2010
increasingly more prevalent within a higher number of interventional radiology suites. Care during transport is focused on achieving hemodynamic stability and rapid transfer to a comprehensive treatment facility. The classic scenario for involvement of air medical transport is an unsuspected placenta accreta that is found during cesarean section at an outlying facility that lacks additional surgical or interventional radiologic resources. The facility rapidly exhausts available resources and requests transfer to a facility with more extensive resources. In this scenario, the limited availability of blood products at outlying facilities may necessitate the transport team bringing additional products with them on the flight. If blood products are not available, the administration of colloids such as hetastarch (Hespan) or albumin may be beneficial. If the patient remains hypoperfused after the administration of blood products, vasopressors may be necessary. As the patient in the case presentation illustrates, the use of a single pressor may not be adequate. Transport teams must ensure they have additional vasopressors available. It may also be necessary to use additional medications from the referring facility. Given the nature of hypovolemic shock, commonly used vasopressors include dopamine (in high doses 10-20 mcg/kg/min), norepinephrine, and neosynephrine.8 Caution must be exercised to avoid relative hypertension, as this may decrease clot formation and increase hemorrhage. In addition, proactive and aggressive airway management should be considered because of the altered mentation that may accompany hypoperfusion. Caution should be used in the selection of induction agents because of the hypotension that accompanies several commonly used medications. Given the necessity for large volumes of blood products, calcium levels should be monitored, as replacement will likely be necessary. During care and subsequent transport, several monitoring parameters should be considered. As with any bleeding patient requiring massive blood transfusion, the goal of 1:1 replacement should be followed.9 This may also require platelets and FFP; cryoprecipitate may also be considered. Given the difficulty of estimating blood loss, the use of measured hemoglobin may be useful. Obtained in conjunction with an arterial blood gas, the base deficit may also aid in volume replacement. Additionally, coagulation studies should be completed as a result of the high potential for disseminated intravascular coagulation. Transport should not be delayed awaiting return of laboratory results. In lieu of rapidly available laboratory measurements, the heart rate, blood pressure, and, if available, central venous pressure and urine output may be used. Desirable treatment responses include increased mentation, improved capillary refill, central venous pressure greater than or equal to 8mmHg, mean arterial blood pressure greater than 80 mmHg, and urinary output 30-60 mL/hr or greater. As this case demonstrates, a complex obstetrical patient may be every bit as complicated as more commonly seen 125
trauma or medical patients. However, given the lower case frequency and high potential for mortality, it may be more stressful for transport crews. As the number of cesarean sections increases, the likelihood of transporting a patient with placenta accreta also increases. Additional education at both the local and industry level will ultimately prove beneficial toward successful treatment of these patients.
References 1. The Prevention and Management of Postpartum Haemorrhage: Report of Technical Working Group, Geneva 3-6 July 1989. Geneva: World Health Organization, 1990. 2. Stones RW, Paterson CM, Saunders NJ. Risk factors for major obstetric haemorrhage. Eur J Obstet Gynecol Reprod Biol 1993;48:15-8. 3. Sherman SJ, Greenspoon JS, Nelson JM, Paul RH. Identifying the obstetric patient at high risk of multiple-unit blood transfusions. J Reprod Med 1992;37:649-52. 4. Miller DA. Obstetric hemorrhage. December 18, 2002. Available at http://www.obfocus.com/high-risk/bleeding/hemorrhagepa.htm. Accessed March 15, 2010. 5. Clark SL, Koonings PP, Phelan JP. Placenta previa/accreta and prior cesarean section. Obstet Gynecol. 1985;66:89-92. 6. Levine D, et al. Placenta accreta: evaluation with color Doppler US, power Doppler US, and MRI imaging. Radiology. 1997;205:773-776. 7. Descargues G, Douvrin F, Degre S, et al. Abnormal placentation and selective embolization of the uterine arteries. Eur J Obstet Gynecol Reprod Biol. 2001;99(1):47-52. 8. Wilson M, Davis DP, Coimbra R. Diagnosis and monitoring of hemorrhagic shock during the initial resuscitation of multiple trauma patients: a review. J Emerg Med. 2003;24(4):413-22. 9. Ketchum L, Hess JR, Hiippala S. Indications for Early Fresh Frozen Plasma, Cryoprecipitate and Platelet Transfusion in Trauma. J Trauma 2005:60:6:S51-S58.
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Air Medical Journal 29:3