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Revista Colombiana de Anestesiología

Print version ISSN 0120-3347

Rev. colomb. anestesiol. vol.39 no.2 Bogotá Apr./July 2011

http://dx.doi.org/10.5554/rca.v39i2.96 

Investigación Científica y Tecnológica

Maternal Critical Care: Outcomes and Patient Characteristics in a Combined Obstetric High Dependency Unit in Medellín, Colombia

Germán A. Monsalve*, Catalina M. Martínez**, Tatiana Gallo**, María Virginia González**, Gonzalo Arango**, Alejandro Upegui**, Juan Manuel Castillo**, Juan Guillermo González**, Jorge Rubio***, Leonardo Mojica****, Mauricio de Jesús Vasco*****

* Médico Anestesiólogo, Coordinador Unidad de Alta Dependencia Obstétrica, Clínica del Prado, Medellín, Colombia. Correspondencia: Carrera 50A No.64-42, Medellín, Colombia. Correo electrónico: gerafomejia@yahoo.com
** Anestesiólogos Unidad de Alta Dependencia Obstétrica, Clínica del Prado. Medellín, Colombia
*** Anestesiólogo cardiovascular Unidad de Alta Dependencia Obstétrica, Clínica del Prado. Medellín, Colombia.
**** Anestesiólogo intensivista Unidad de Alta Dependencia Obstétrica, Clínica del Prado, Medellín, Colombia.
***** Anestesiólogo Coordinador Comité Anestesia Obstétrica SCARE. Anestesiólogo Clínica Reina Sofía, Organización Sanitas Internacional, Bogotá, Colombia. Correo electrónico: machuchovasco@yahoo.com

Recibido: septiembre 5 de 2010. Enviado para modificaciones: octubre 4 de 2010. Aceptado: abril 1 de 2011.


SUMMARY

The critically ill obstetric patient represents a complex clinical challenge that requires a multi-disciplinary approach. The aim of our study was to assess the utilization rate, admission diagnosis and maternal-fetal outcome of critically ill obstetrical patients admitted in a single institution high dependency/Intensive care Unit in Colombia, Latin America. A 3-year retrospective review of hospital records was completed. Eight hundred and nineteen patients were admitted in a 3 year period, representing 3.3 % of all deliveries, 64 % of the admissions were in the antepar-tum period. Obstetric complications accounted for 82 % of admissions; the preeclampsia - eclampsia and its complications were the most common diagnosis (50.5 %) and obstetric hemorrhage was the primary cause of severe morbidity and mortality. There were seven deaths (0.85 %). The average length of stay at the unit was 2.41 days (1-15). Nine patients were transferred to a medical/surgical Intensive Care Unit during the study. Uses of an exclusive Obstetric high dependency unit includes the concurrent availability of an obstetric, perinatal and critical care management, with low threshold for admission either antenatal or in the postnatal period, that allow an efficient and opportune management of the complex obstetric patient.

Keywords: Maternal mortality, pre-eclampsia, eclampsia, hemorrhage. (Source: MeSH, NLM).


INTRODUCTION

The critically ill obstetric patient represents a challenge that usually requires a multidisci-plinary approach. Around 7/1000 pregnant women require Intensive Care Units (ICU) admission (1) with a mortality rate that ranges between 2.2 % to 36 % (2,3).

Most published studies in this group of patients are descriptive, reporting admission diagnosis, morbidity and mortality (4). There are significant differences in admission diagnosis and outcomes when comparing developing (5) and developed (6) countries. Complications of severe Preeclampsia, hemorrhage and severe sepsis are the most common obstetric causes for admission to the ICU around the world (7).

The concept of Obstetric High Dependency Unit (OHDU) has been introduced in the literature mainly from UK hospitals (8), suggesting that its availability may potentially reduce the transfer to ICU and diseases' associated mortality.

The aim of our study was to assess the utilization rate, admission diagnosis and maternal-fetal outcome of critically ill obstetrical patients admitted in a single institution high dependency/Intensive care Unit applying the concept of low threshold and early admission.

MATERIAL AND METHODS

Clínica Del Prado is an obstetric center with approximately 8,000 deliveries per year, with a rate of cesarean sections of 32 % and a proportion of high-risk obstetric patients of 20 %. It is the major obstetric centre in Medellin, Colombia.

Patients admitted to the OHDU of the Clínica del Prado between November of 2005 and November of 2008 were included in this report. The OHDU has 6 beds, equipped with invasive, non invasive hemodynamic maternal monitoring and fetal continuous monitoring. One bed has the capability of mechanical ventilation and measurement of cardiac output with pulmonary artery catheter (PAC) or minimally invasive monitoring. Renal replacement therapy is available by nephrology if is needed.

The unit is located adjacent to the Post Anesthetic Care Unit, Operating rooms and delivery rooms; it is staffed by anesthesiologists, with availability 24 hours a day of specialists in maternal-fetal medicine, surgery, respiratory therapy, blood bank services and a relation nurse/patient of 1 to 2. Throughout the hospitalization, if pertinent, the new born remain next to the mother by the availability of open servocrib. There is complete availability of epidural or systemic analgesia for labor and delivery in mothers that can't be transferred to the delivery room because of the severity of her disease or because of the use of invasive hemodynamic monitoring, can be done at the unit.

DATA COLLECTION

After approval by institutional review board, we revised the charts of all pregnant patients and patients admitted in the first 40 postpar -tum days to the OHDU. Information was pro-spectively collected as part of the OHDU standard operating protocol, including the following data: age, gestational age, pregnancies, assistance to prenatal care, parity, main diagnosis for admission differentiating between obstetrics pathologies and the presence of co morbid conditions; therapeutic intervention (i.e. mechanical ventilation, hemodynamic invasive monitoring, renal replacement therapy and the use of vasoactive medication); time between onset of symptoms and admission, major obstetric morbidity, (organ failure, need for transfusions and therapeutic interventions); post-operative complications, length of stay in the unit, referrals to ICU, transfer of the newborn to the neonatal intensive care unit (NICU) and fetal and maternal mortality.The severity score used was the APACHE II (9). The shock state was defined by the Conference and International Consensus 2000 (10). ARDS by the Confer -ence and Consensus American-European (11). Severe sepsis, septic shock and multi organic dysfunction syndrome (MODS), according to the definition of the Thoracic American College and the Critical Care Medicine society (12). Disseminated Intravascular Coagulation (DIC) was defined according to thrombosis and hemostasis score13. Perinatal and Maternal Mortality was defined according to the Inter -national Classification of Illnesses14 as every death that occurs during pregnancy until the first 6 postpartum weeks.

RESULTS

During the study period (3 years) 819 patients were admitted to the OHDU, representing the 3.3 % of the 24,749 deliveries in our institution. Demographics are illustrated in the Table 1. The APACHE II score at 24 hours was 9.13 + 6.2 (mean + SD) with 11.62 % of predicted mortality. The average length of stay at the unit was 2.41 days (1-15). Obstetric reasons for admission were 82 % (Table 2) with an antepartum admission rate of 64 %. Severe preeclampsia including HELLP syndrome and major obstetric hemorrhage were the main admission diagnoses; morbidity associated to severe preeclampsia is shown in the Graphic 1. The main reason for admission due to obstetric hemorrhage was uterine atony and placenta accreta. All patients taken to Emergency Peri-partum Hysterectomy (EPH) were admitted to the OHDU. The incidence of EPH was 2.1/ 1000 deliveries during the study period. Other obstetric admission causes were acute fatty liver of pregnancy (AFLP), amniotic fluid embolism (AFE), peripartum Cardiomyopathy (PC), sepsis secundary to abortion and continuous fetal monitoring in patients with high risk of fetal intrapartum death.

Non obstetric causes for admission were severe sepsis and septic shock mainly from urinary, pulmonary and intraabdominal sources. The second cause for medical admission was cardiac disease, including rheumatic valvular disease, rhythm abnormalities and antico-agulation therapy in patients with mechanical prosthetic valves. Among respiratory conditions, non fatal pulmonary thromboembolism was the main cause for admission; other diagnoses were severe pneumonia and ARDS. The endocrine reasons were diabetes mellitus complications mainly diabetic ketoacidosis and ges-tational diabetes. Sickle-cell disease, idiopathic thrombocytopenic purpure, Von Willembrand's disease, cyclic neutropenia and severe throm-bocytopenia associated to malaria and dengue hemorrhagic fever, were the main causes of hematologic admissions.

Among the anesthetic complications, total spinal anesthesia and difficult airway management complications were the main causes for admission. Interventions and procedures in the OHDU are shown in the Table 3.

Transfer to another ICU was required primarily for patients that need subspecialty evaluation that was not available at our center. (table 4); i.e. one patient with an AFLP and liver failure who required evaluation for a liver transplantation group and two cases of peripartum cardio-myopathy to be evaluated for the cardiac transplantation group.

During this 3 year study period, 7 mothers died corresponding to 0.85 % of all admissions. APACHE II in this group of patients was 29.5 + 2.4 (mean + SD) with 67.2 % of predicted mortality. The causes of death are tabulated in table 5. The main cause of death was MODS associated to a hemorrhagic shock in 57.1 % (4 patients). Perinatal deaths were 42 corresponding to 8% from the total of patients admitted antepartum.

DISCUSSION

Utilization of critical care services for obstetric patients has been reported previously in ranges that vary from 0.1 to 1 % of all deliveries (15,16), and is frequently done in general surgical/medical intensive care units; uses of HDU in obstetric scenarios have been described in ranges between 1.1-2.67 % (8,17). Our admission incidence was 3.3 %, similar to other case series (18), probably because we have a high rate of patients that are referred from other centers, a growing high risk obstetric service and a low threshold for admission.

Zeeman and Cols (17) report their admissions using the concept of integrated intermediate-intensive care units for the care of the critically ill pregnant patient. It consists in a special care unit that seeks for an impact in decreasing morbidity and mortality in patients with acute organ dysfunction (compromise of maximum 2 organs), who require higher monitoring and surveillance than what is offered in a general ward and if not treated appropriately could result in death ("near misses") (19).

Medical and surgical ICUs in our city have an extremely high occupancy rate and early referral of obstetric patients to these units is especially difficult; due to this situation we decided to create an OHDU in our center. Since the establishment of the unit, the complexity of the patient's pathology has increased demanding in some of them a higher level of care, even reaching classic criteria for ICU admission like mechanical ventilation, use of a PAC, vasopressor and ino-tropic support and renal replacement therapy, interventions that can be provided in a timely fashion.

Karnad et al. (20) describe an ICU antepartum admission rate of 45.4 %; this proportion in our unit was 64 %. The early admission allows us to begin treatment when patients are "still pregnant". Commonly, staff from medical/surgical ICUs is not familiarized with aspects of obstetric pathology such as continuous fetal monitoring or procedures like deliveries in patients in whom the risk of transportation to the delivery suite is significant, either due to severity of the disease or the need for strict hemodynamic monitoring during the entire peripartum period.

Since our institution is an urban referral center, most of the admissions are patients who live in the city or in adjacent rural areas, with a high proportion of prenatal care (92 %) opposed to other reports where mortality is directly related to a low prenatal care. Munnur et al 21 report that obstetric patients admitted to an ICU who did not receive prenatal care had higher APACHE II scores compared with patients receiving regular prenatal care.

The main causes for admission to our unit were complications of preeclampsia- eclampsia and hemorrhagic events as has been reported in other case series (22). This report shows a high need for arterial invasive hemodynamic monitoring, in accordance with the major admission diagnosis. As part of our protocol, we use an arterial line to strictly control blood pressure and diminish hemorrhagic CNS complications in these patients(23). During the study period we had only one case of an intraparenchimal cerebral hemorrhage secondary to severe hypertension in a patient that was admitted from another institution already with this complication, no surgical treatment was required she was discharged without neurological disability. The incidence of pulmonary edema was 6 %, higher than 3 % previously reported by Sibai et al (24). When a PAC was required for the diagnosis and treatment of pulmonary edema, ventricular dysfunction was observed In 10 % of the cases, similar to previous reports in severe preeclampsia using non invasive and invasive monitoring (25). The Incidence of acute renal failure in preeclamptic patients was 5.8 %, associated entirely with the presence of HELLP syndrome, mostly in patients who were referred from other institutions in whom diagnosis were delayed. However renal replacement therapy was necessary in only 1 %. This incidence is lower than reported by Drakeley et al (26) in which dialysis need in preeclamptic patients admitted in a medical ICU was 10 %.

The second cause of admission to the OHDU was major obstetric hemorrhage secondary mainly to uterine atony and placenta accreta, in spite of having protocols of prophylaxis and pharmacological treatment of uterine atony (oxytocin, misoprostol, methergine and carbe-tocin) and protocols to diagnose placenta accreta in high risk patients( placenta previa and uterine scars). When medical treatment fails, the next measures to control hemorrhage in our centre are haemostatic sutures and hysterectomy with an elevated morbidity given by a high rate of transfusion and relaparotomy 27. As mentioned previously, we have a high incidence of EPH (2.1/ 1000 deliveries) as definitive measure to control hemorrhage compared to previous reports 28 , we don't have early availability of measures widely recognized to treat uterine atony as uterine balloon tamponade, hypogastric arterial ligation and interventional radiology.

Six patients were admitted with confirmed diagnosis of pulmonary thromboembolism. None of them presented cardiovascular collapse, right ventricular dysfunction or other findings suggestive of massive embolism, at any time. Most of these patients were in early postpartum period but two of them were 18 and 29 weeks of gestation respectively in whom thrombophilia was confirmed. We have included systematically, spiral computed tomography in our algorithm of diagnosis in all obstetric patients with suspected pulmonary embolism (PE) since the potential risks associated with this test, are minimal compared with the consequences of misdiagnosis (29). Patients with PE received initial anticoagulant therapy with low molecular weight heparins (LMWH) initially and later warfarin was maintained for minimum 6 months.

In our institution, all the pregnant patients with diagnosis of severe sepsis and septic shock for any cause are admitted to the OHDU ideally in the first 6 hours to initiate the early gold therapy protocol in severe sepsis (30). Although obstetric patients were excluded in the Rivers et al. original protocol, we have incorporated it as a strategy of management in this group of patients. We had 40 patients admitted with this diagnosis in which we applied the protocol finding a high rate of interventions and low rate of complications and mortality (31).

Four patients died secondary to obstetric hemorrhage in our unit during the study period; two patients after uterine atony, one secondary to placental abruption and one due to uterine rupture. In three of these patients peripartum hysterectomy was required, and in one, a perimortem cesarean section was performed after uterine rupture. MODS was the end cause of death in this group of patients, persistent coagulopathy after 24 hours of hysterectomy and a high consumption of blood products was observed. Obstetric hemorrhage is the second cause of maternal mortality in Latin America after hypertensive disorders (32). Sosa et al (33) report that retained placenta, multiple pregnancy, macrosomia (defined as a birth weight of 4,000 g or more), episiotomy, and suture are all risk factors for severe morbidity secundary to hemorrhage in a Latin American population; on the other hand another risk factors, such as maternal age, multiparity augmentation, induction with oxytocin during the first or second stage of labor, and preterm birth, were not associated with increased risk of severe postpartum hemorrhage. In our report mortality secondary to hemorrhage was associated to multiparity, late admission and delayed transfusion of blood components in the patients admitted from another centers.

Three patients died from other causes: the first patient was a 32 weeks pregnant patient, who developed an AFLP, with associated acute liver failure and a grade III encephalopathy in whom a cesarean section under general anesthesia was performed; she required vasopressor and inotropic support and renal replacement therapy in our unit. She was referred to a center with the possibility of liver transplantation where she died after a fatal brain hemorrhage. The second patient a 40 week pregnant, 17 year old patient, who three minutes after cesarean delivery under epidural anesthesia, developed neurologic compromise followed by cardiovascular collapse and severe coagulopathy; an amniotic fluid embolism was suspected, 8 hours later, she died in spite of inotropic, vasopressor and use of blood products. The third case was a 20 week pregnant, 21 years old patient with a septic shock secondary to septic abortion. The maternal mortality in AFLP is reported with values as low as 18 %. Infectious and bleeding complications remain the most life threatening. Liver transplantation has a very limited role, because of the great potential for recovery with delivery but should be considered in patients whose clinical course continues to deteriorate with advancing fulminant hepatic failure after the first 1 to 2 days postpartum without signs of hepatic regeneration (34). Amniotic fluid embolism syndrome accounts for approximately 10 % of all maternal deaths in the United States and can result in permanent neurologic deficits in up to 85 % of survivors (35).We don't have data about the incidence of AFE in Colombia, and exact diagnosis of this entity is not always possible due to the lack of systematic autopsy in events of maternal mortality. We had no fatalities in patients with preexisting medical conditions in spite of severe organic involvement especially in patients admitted with tropical infectious diseases like malaria, dengue hemorrhagic fever or septic shock associated to zoonosis.

With the aim of evaluating the severity of patient's disease at 24 hours from admission, we use, although debated in these group of patients, the APACHE II score. The observed mortality rate in our group was much lower than predicted. This observation has been already reported in the past where has been proved that the APACHE II score is a model that has a good discrimination but overestimates mortality and it may be possible to recalibrate the APACHE II for obstetric admissions or to develop a new specific model (36).

Pollock et al (37) did a systematic review of all publications of obstetric intensive care admissions, including a total of 40 eligible studies reporting outcomes for 7,887 women; they conclude that the ICU admission profile of women was similar in developed and developing countries; however, the maternal mortality rate remains higher for ICUs in developing countries, supporting the need for ongoing service delivery improvements.

Our study shows a group of patients with classic admission criteria to a combined OHDU/ ICU with low mortality rates probably associated to low threshold of admissions, an elevated rate of prenatal care and a high proportion of patients with a low interval between onset of illnesses and admission to the OHDU; all these issues have previously been reported as directly related with mortality (20,21).

To our knowledge this is the first report in Latin America using the concept of OHDU as an strategy used in high occupancy obstetric centers and specially in developing countries, where referral of obstetric patients to ICU's is very difficult in order to provide better care of the high risk pregnant patient and to improve the transition between the operating/delivery room and the ICU's, furthermore is useful by treating patients admitted with special conditions that should not be treated in a general ward.

In summary, the creation of the OHDU in our institution, being the biggest obstetric center in our city, has allowed us to manage obstetric patients with rare medical conditions and the usual complications of the common obstetric pathology. The initial admission criteria proposed at the creation of our unit have been broadened to more complex diseases; initially we were an intermediate care unit and a bridge to ICUs, now we are able to manage patients with some classic ICU criteria, in an appropriate environment that includes the possibility of treating them while pregnant and during labor. Decisions about pregnant patient care in the OHDU should be made collaboratively with the anesthesiologist, maternal-fetal specialists, nurses, and neonatologist. Applying the concept of low threshold and early antepartum admission in high income obstetric centers, would possibly decrease the mortality associated to this group of patients.

REFERENCES

1. Hazelgrove JF, Price C, Pappachan VJ, et al. Multicenter study of obstetric admissions to 14 intensive care units in southern England. Crit Care Med. 2001;29:770-5.

2. Bouvier-Colle MH, Salanave B, Ancel PY, et al. Obstetric patients treated in intensive care units and mortality. Eur J Obstet Gynecol Reprod Biol. 1996;65:121-5.

3. Dias de Souza JP, Duarte G, Basile-Filho A. Near-miss maternal mortality in developing countries. Eur J Obstet Gynecol Reprod Biol. 2002;104:80.

4. Kilpatrick SJ, Matthay MA. Obstetric patients requiring critical care. A five year review. Chest. 1992;101:1407-12.

5. Vásquez DN, Estenssoro E, Canales HS, et al. Clinical characteristics and outcomes of obstetric patients requiring ICU admission. Chest. 2007;131: 718-24.

6. Collop NA, Sahn SA. Critical illness in pregnancy. An analysis of 20 patients admitted to a medical intensive care unit. Chest. 1993;103:1548-52.

7. Panchal S, Arria A, Harris P, et al. Intensive care utilization during hospital admission for delivery. Anesthesiology. 2000;92:1537-44.

8. Ryan M, Hamilton V, Bowen M, et al. The role of a high-dependency unit in a regional obstetric hospital. Anaesthesia 2000;55:1155-58.

9. Knaus WA, Draper EA, Wagner DP, et al. APACHE II: a severity of disease classification system. Crit Care Med. 1985;13:818-29.

10. Antonelli M, Levy M, Andrews PJ, et al. Hemodynamic monitoring in shock and implications for management. International Consensus Conference. Intensive Care Med. 2007;33:575-90.

11. Bernard GR, Artigas A, Brigham KL, et al. The American-European Consensus Conference on ARDS. Definitions, mechanisms, relevant outcomes, and clinical trial coordination. Am J Respir Crit Care Med. 1994;149:818-24.

12. Marshall JC, Cook DJ, Christou NV, et al. Multiple organ dysfunction score: a reliable descriptor of a complex clinical outcome. Crit Care Med. 1995;23: 1638-52.

13. Taylor FB Jr, Toh CH, Hoots WK, et al. Towards definition, clinical and laboratory criteria, and a scoring system for disseminated intravascular coagulation. Thromb Haemost. 2001;86:1327-30.

14. World Health Organization (WHO). International statistical classification of diseases and related health problems, 10th revision. Geneva: WHO; 1992.

15. Lapinsky SE, Kruczyinski K, Slutsky AS. Critical care in the pregnant patient. Am J Respir Crit Care Med. 1995;152:427-55.

16. Lapinsky SE, Kruczynski K, Seaward GR, et al. Critical care management of the obstetric patient. Can J Anaesth. 1997;44:325-29.

17. Zeeman GG, Wendel GD Jr, Cunningham FG. A blueprint for obstetric critical care. Am J Obstet Gynecol. 2003;188:532-6.

18. Saravanakumar K, Davies L, Lewis M, et al. High dependency care in an obstetric setting in the UK. Anaesthesia. 2008;63:1081-6.

19. Baskett TF, Sternadel J. Maternal intensive care and near-miss mortality in obstetrics. Br J Obstet Gy-naecol. 1998;105:981-4.

20. Karnad DR, Lapsia V, Krishnan A, et al. Prognostic factors in obstetric patients admitted to an Indian intensive care unit. Crit Care Med. 2004;32:1294-9.

21. Munnur U, Karnad DR, Bandi VD, et al. Critically ill obstetric patients in an American and an Indian public hospital: comparison of case-mix, organ dysfunction, intensive care requirements, and outcomes. Intensive Care Med. 2005;31:1087-94.

22. Mahutte NG, Murphy-Kaulbeck L, Le Q, et al. Obstetric admissions to the intensive care unit. Obstet Gynecol. 1999;94:263-6.

23. Martin JN Jr, Thigpen BD, Moore RC, et al. Stroke and severe preeclampsia and eclampsia: a paradigm shift focusing on systolic blood pressure. Obstet Gynecol. 2005;105:246-54.

24. Sibai BM, Mabie BC, Harvey CJ, et al. Pulmonary edema in severe preeclampsia-eclampsia: analysis of thirty-seven consecutive cases. Am J Obstet Gynecol. 1987;156:1174-9.

25. Gilbert WM, Towner DR, Field NT, et al. The safety and utility of pulmonary artery catheterization in severe preeclampsia and eclampsia. Am J Obstet Gynecol. 2000;182:1397-403.

26. Drakeley AJ, Le Roux PA, Anthony J, et al. Acute renal failure complicating severe preeclampsia requiring admission to an obstetric intensive care unit. Am J Obstet Gynecol. 2002;186:253-6.

27. Cardona A; Monsalve G; Vasco M, et al. Obstetric hemorrhage: morbidity and mortality in a high dependency unit in Medellin, Colombia South America. Poster presentations. Journal of Perinatal Medicine. 2007;35(s2):S101-S301.

28. Flood KM, Said S, Geary M, et al. Changing trends in peripartum hysterectomy over the last 4 decades. Am J Obstet Gynecol. 2009;200:632.e1-6.

29. Marik PE, Plante LA. Venous thromboembolic disease and pregnancy. N Engl J Med. 2008;359: 2025-33.

30. Rivers E, Nguyen B, Havstad S, et al. Early goal-directed therapy in the treatment of severe sepsis and septic shock. N Engl J Med. 2001;345:1368-77.

31. Monsalve G, Arango G, Osorio A, Arango J, Mojica L, et al. Early Goal Directed Therapy (EGDT) for severe sepsis and sep- tic shock in the pregnant patient. outcome in 34 consecutive patients. Anesth Analg. 2008; 106:A-202.

32. Khan KS, Wojdyla D, Say L, et al. WHO analysis of causes of maternal death: a systematic review. Lancet. 2006;367:1066-74.

33. Sosa CG, Althabe F, Belizán JM, et al. Risk factors for postpartum hemorrhage in vaginal deliveries in a Latin-American population. Obstet Gynecol. 2009;113:1313-9.

34. Hay JE. Liver disease in pregnancy. Hepatology. 2008;47:1067-76.

35. Moore J, Baldisseri MR. Amniotic fluid embolism. Crit Care Med. 2005;33:S279-85.

36. Harrison DA, Penny JA, Yentis SM, Fayek S. Case mix, outcome and activity for obstetric admissions to adult, general critical care units: a secondary analysis of the ICNARC Mix Programme Database. Critical Care. 2005;9:S25-37.

37. Pollock W, Rose L, Dennis CL. Pregnant and postpar-tum admissions to the intensive care unit: a systematic review. Intensive Care Med. 2010;36:1465-74.

Conflicto de intereses: Ninguno declarado.
Financiación: Recursos propios de los autores.

1. Hazelgrove JF, Price C, Pappachan VJ, et al. Multicenter study of obstetric admissions to 14 intensive care units in southern England. Crit Care Med. 2001;29:770-5.         [ Links ]

2. Bouvier-Colle MH, Salanave B, Ancel PY, et al. Obstetric patients treated in intensive care units and mortality. Eur J Obstet Gynecol Reprod Biol. 1996;65:121-5.         [ Links ]

3. Dias de Souza JP, Duarte G, Basile-Filho A. Near-miss maternal mortality in developing countries. Eur J Obstet Gynecol Reprod Biol. 2002;104:80.         [ Links ]

4. Kilpatrick SJ, Matthay MA. Obstetric patients requiring critical care. A five year review. Chest. 1992;101:1407-12.         [ Links ]

5. Vásquez DN, Estenssoro E, Canales HS, et al. Clinical characteristics and outcomes of obstetric patients requiring ICU admission. Chest. 2007;131: 718-24.         [ Links ]

6. Collop NA, Sahn SA. Critical illness in pregnancy. An analysis of 20 patients admitted to a medical intensive care unit. Chest. 1993;103:1548-52.         [ Links ]

7. Panchal S, Arria A, Harris P, et al. Intensive care utilization during hospital admission for delivery. Anesthesiology. 2000;92:1537-44.         [ Links ]

8. Ryan M, Hamilton V, Bowen M, et al. The role of a high-dependency unit in a regional obstetric hospital. Anaesthesia 2000;55:1155-58.         [ Links ]

9. Knaus WA, Draper EA, Wagner DP, et al. APACHE II: a severity of disease classification system. Crit Care Med. 1985;13:818-29.         [ Links ]

10. Antonelli M, Levy M, Andrews PJ, et al. Hemodynamic monitoring in shock and implications for management. International Consensus Conference. Intensive Care Med. 2007;33:575-90.         [ Links ]

11. Bernard GR, Artigas A, Brigham KL, et al. The American-European Consensus Conference on ARDS. Definitions, mechanisms, relevant outcomes, and clinical trial coordination. Am J Respir Crit Care Med. 1994;149:818-24.         [ Links ]

12. Marshall JC, Cook DJ, Christou NV, et al. Multiple organ dysfunction score: a reliable descriptor of a complex clinical outcome. Crit Care Med. 1995;23: 1638-52.         [ Links ]

13. Taylor FB Jr, Toh CH, Hoots WK, et al. Towards definition, clinical and laboratory criteria, and a scoring system for disseminated intravascular coagulation. Thromb Haemost. 2001;86:1327-30.         [ Links ]

14. World Health Organization (WHO). International statistical classification of diseases and related health problems, 10th revision. Geneva: WHO; 1992.         [ Links ]

15. Lapinsky SE, Kruczyinski K, Slutsky AS. Critical care in the pregnant patient. Am J Respir Crit Care Med. 1995;152:427-55.         [ Links ]

16. Lapinsky SE, Kruczynski K, Seaward GR, et al. Critical care management of the obstetric patient. Can J Anaesth. 1997;44:325-29.         [ Links ]

17. Zeeman GG, Wendel GD Jr, Cunningham FG. A blueprint for obstetric critical care. Am J Obstet Gynecol. 2003;188:532-6.         [ Links ]

18. Saravanakumar K, Davies L, Lewis M, et al. High dependency care in an obstetric setting in the UK. Anaesthesia. 2008;63:1081-6.         [ Links ]

19. Baskett TF, Sternadel J. Maternal intensive care and near-miss mortality in obstetrics. Br J Obstet Gy-naecol. 1998;105:981-4.         [ Links ]

20. Karnad DR, Lapsia V, Krishnan A, et al. Prognostic factors in obstetric patients admitted to an Indian intensive care unit. Crit Care Med. 2004;32:1294-9.         [ Links ]

21. Munnur U, Karnad DR, Bandi VD, et al. Critically ill obstetric patients in an American and an Indian public hospital: comparison of case-mix, organ dysfunction, intensive care requirements, and outcomes. Intensive Care Med. 2005;31:1087-94.         [ Links ]

22. Mahutte NG, Murphy-Kaulbeck L, Le Q, et al. Obstetric admissions to the intensive care unit. Obstet Gynecol. 1999;94:263-6.         [ Links ]

23. Martin JN Jr, Thigpen BD, Moore RC, et al. Stroke and severe preeclampsia and eclampsia: a paradigm shift focusing on systolic blood pressure. Obstet Gynecol. 2005;105:246-54.         [ Links ]

24. Sibai BM, Mabie BC, Harvey CJ, et al. Pulmonary edema in severe preeclampsia-eclampsia: analysis of thirty-seven consecutive cases. Am J Obstet Gynecol. 1987;156:1174-9.         [ Links ]

25. Gilbert WM, Towner DR, Field NT, et al. The safety and utility of pulmonary artery catheterization in severe preeclampsia and eclampsia. Am J Obstet Gynecol. 2000;182:1397-403.         [ Links ]

26. Drakeley AJ, Le Roux PA, Anthony J, et al. Acute renal failure complicating severe preeclampsia requiring admission to an obstetric intensive care unit. Am J Obstet Gynecol. 2002;186:253-6.         [ Links ]

27. Cardona A; Monsalve G; Vasco M, et al. Obstetric hemorrhage: morbidity and mortality in a high dependency unit in Medellin, Colombia South America. Poster presentations. Journal of Perinatal Medicine. 2007;35(s2):S101-S301.         [ Links ]

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