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treated by trans-sphenoidal selective adenomectomy in mid-pregnancy. 2001; 57: 554.
Br. J. Anaesth. 1998; 80: 850“2. 123. Dahan, M. & Chang, R. J. Pancreatitis secondary to hyperparathyroidism
110. Hana, V., Dokoupilova, M., Marek, J. & Plavka, R. Recurrent during pregnancy. Obstet. Gynecol. 2001; 98: 923“5.
ACTH-independent Cushing™s syndrome in multiple pregnancies and 124. Jaafar, R., Yun Boo, N., Rasat, R. & Latiff, H. A. Neonatal seizures due to
its treatment with metyrapone. Clin. Endocrinol. 2001; 54: 277“81. maternal primary hyperparathyroidism. J. Paediatr. Child Health 2004; 40:
111. Berwaerts, J., Verhelst, J., Mahler, C. & Abs, R. Cushing™s syndrome in 329.
pregnancy treated by ketoconazole: case report and review of the litera- 125. Schnatz, P. F. Surgical treatment of primary hyperparathyroidism during
ture. Gynecol. Endocrinol. 1999; 13: 175“82. the third trimester. Obstet. Gynecol. 2002; 99: 961“3.
112. Glassford, J., Eagle, C. & McMorland, G. H. Caesarean section in a patient 126. Tollin, S. R. Course and outcome of pregnancy in a patient with mild,
with Cushing™s syndrome. Can. Anaesth. Soc. J. 1984; 31: 447“50. asymptomatic, primary hyperparathyroidism diagnosed before concep-
113. Okawa, T., Asano, K., Hashimoto, T. et al. Diagnosis and management of tion. Am. J. Med. Sci. 2000; 320: 144“7.
primary aldosteronism in pregnancy: case report and review of the litera- 127. Schnatz, P. F. & Curry, S. L. Primary hyperparathyroidism in
ture. Am. J. Perinatol. 2002; 19: 31“6. pregnancy: evidence-based management. Obstet. Gynecol. Surv. 2002;
114. Ganguly, A. Primary aldosteronism. N. Engl. J. Med. 1998; 339: 1828“34. 57: 365“76.
115. Wyckoff, J. A., Seely, E. W., Hurwitz, S. et al. Glucocorticoid-remediable 128. Negishi, H., Kobayashi, M., Nishida, R. et al. Primary hyperparathyroidism
aldosteronism and pregnancy. Hypertension 2000; 35: 668“72. and simultaneous bilateral fracture of the femoral neck during pregnancy.
116. New, M. I. Antenatal diagnosis and treatment of congenital adrenal hyper- J. Trauma 2002; 52: 367“9.
plasia. Curr. Urol. Rep. 2001; 2: 11“18. 129. Callies, F., Arlt, W., Scholz, H. J. et al. Management of hypoparathyroidism
117. Hoepffner, W., Schulze, E., Bennek, J. et al. Pregnancies in patients with during pregnancy “ report of twelve cases. Eur. J. Endocrinol. 1998; 139:
congenital adrenal hyperplasia with complete or almost complete impair- 284“9.
ment of 21-hydroxylase activity. Fertil. Steril. 2004; 81: 1314“21. 130. Mather, K. J., Chik, C. L. & Corenblum, B. Maintenance of serum
118. Krone, N., Wachter, I., Stefanidou, M. et al. Mothers with congenital calcium by parathyroid hormone-related peptide during lactation
adrenal hyperplasia and their children: outcome of pregnancy, birth and in a hypoparathyroid patient. J. Clin. Endocrinol. Metab. 1999; 84:
childhood. Clin. Endocrinol. 2001; 55: 523“9. 424“7.




292
SECTION 5: OTHER DISORDERS
BLOOD DISORDERS
17
M. Joanne Douglas and Penny Ballem



Background preexisting disorders or in response to an acute peripartum com-
plication such as acute abruption with DIC, severe preeclampsia,
Normal hematological indices during pregnancy
or postpartum hemorrhage (PPH). Careful counseling of the
Multiple changes occur to the hematological system during preg- patient should be undertaken, even under emergent conditions,
nancy as outlined in Table 17.1.1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 It is to alert them to the risks of blood products. In patients considered
essential that the clinician be familiar with these in order to at high risk of hemorrhage, techniques used to attempt to
determine what is normal and what is abnormal when reviewing decrease the need for homologous transfusion include auto-
logous donation,22 and, at the time of operative delivery, acute
laboratory results in the pregnant woman.
hemodilution.23
Significant advances have been made in the inactivation of
Hematological testing during pregnancy
viruses in the manufacture of fractionated blood products
(e.g. clotting factor preparations); however, it is critical that we
A routine, complete blood count during early pregnancy (first
continue to balance benefit of transfusion with risk of viral trans-
trimester) is important to identify common, preexisting hemato-
mission. Recombinant gene technology has enabled the develop-
logical disorders that may impact on the pregnancy. In the
ment of some products, such as specific coagulation factors.
uncomplicated pregnancy, a repeat blood count in the third
For the most part, the cost of these preparations is still prohibitive
trimester is done to assess the hematocrit in preparation for
and we still remain dependent on plasma-derived products.
delivery.
However, recombinant activated factor VII (rVIIa) is being used
Coagulation screening is performed only:
 to investigate a significant bleeding history increasingly to treat massive hemorrhage in the obstetric patient,
 to follow factor levels in patients with established disorders as well as for specific factor deficiencies or acquired factor inhibi-
tors (see below).24,25,26
 during acute peripartum complications such as preeclampsia,
massive hemorrhage or disseminated intravascular coagulation
(DIC)
Apheresis
 to monitor anticoagulation therapy.
Apheresis involves the separation of blood into its various com-
Screening assays include platelets, prothrombin time (PT),
ponents and is a technique used during pregnancy to treat certain
activated partial thromboplastin time (aPTT), and fibrinogen
conditions (e.g. myasthenia gravis, thrombotic thrombocyto-
(see Table 17.2). The subjective nature of the bleeding time as a
penic pupura), through the removal of a causative antibody. A
measure of platelet function and its established lack of sensitivity
and specificity18,19 as a predictor of clinical bleeding, has pre- complete review on this topic discussed the risks and potential
benefits and outlined the reports where it has been used in
cluded its usefulness.
pregnancy.27
Currently, several centers use thromboelastography (TEG) to
detect the risk of clinical bleeding;20 however, the sensitivity
and specificity of this test remain unproven.21 Another point
of care instrument, the platelet function analyzer (PFA-100’),
Red cell abnormalities and anemias
is thought to represent an ˜˜in vitro™™ bleeding time. Although
small studies have been done in obstetric patients, the evi-
dence at present is insufficient to recommend its routine use Anemia occurs commonly during pregnancy, frequently due
in predicting platelet function and the risk of an epidural to hemodilution, (physiologic anemia of pregnancy) or impro-
hematoma.21 Thus, the ability of any test to predict the risk per nutrition, such as inadequate intake of iron or folate.
of bleeding into the epidural space during regional anesthesia However, the broad spectrum of hemoglobinopathies, thalasse-
remains unknown. mic syndromes, hemolytic anemias, and anemias related to
primary bone marrow disorders can all occur in pregnancy.
Furthermore, there is an increasing number of pregnant women
Transfusion during pregnancy
with chronic disorders, such as renal failure, solid organ trans-
plants, and rheumatologic conditions, which can be associated
The indications for transfusion of blood products during preg-
with anemias related to impaired erythropoiesis or drugs. The
nancy are relatively few. In most instances, the need for blood
management of these patients relates to the potential effect
products arises in preparation for delivery in patients with


Obstetric Anesthesia and Uncommon Disorders, eds. David R. Gambling, M. Joanne Douglas and Robert S. F. McKay. Published by Cambridge University Press.
# Cambridge University Press 2008.
5 Other disorders


Jehovah™s Witness parturients at high risk of hemorrhage or
Table 17.1 Hematological changes of normal in parturients on dialysis. Maternal hypertension has been seen
pregnancy1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 in women on erythropoietin.28
Parameter Direction of change Time of peak or nadir

Anesthetic considerations for the management
Blood volume Increase (45“55%) 34“36 weeks
of parturients with anemia
RBC mass Increase (15“20%) Term
Ferritin Decrease 28“32 weeks
Patients with compensated anemia tolerate anesthesia well. The
MCV Increase 24“28 weeks
choice of anesthetic technique and specific drugs are determined
WBCs Mild“moderate Term
by the underlying disease. There is no clear threshold hemoglobin
increase (25%)
level below which transfusion is essential. In a well-compensated
Platelet count Same or decrease 32“36 weeks (nadir)
patient, with chronic iron deficiency for example, a cesarean
Factors VII, Increase
section (C/S) can be undertaken safely with a hemoglobin
VIII, X, XII
below 8 g/dl. Unless there is evidence of ongoing hemolysis,
Fibrinogen Increase Term
active bleeding or severe symptomatology, compensated anemia
Factor IX Unchanged
should not be treated with transfusion. If transfusion is required
Factor XI Decrease (62%) Term
then proper counseling of the patient should be undertaken with
Protein C Unchanged
regard to the risks. Supplemental oxygen should be administered
Protein S Decrease (40“50%) 12 weeks
to women with a hemoglobin level less than 8 g/dl although 7 g/dl
ATIII Unchanged
is the level when compensatory changes to cardiac output occur.
Regional techniques are not contraindicated unless there is a
RBC ¼ red blood cell; WBC ¼ white blood cell; MCV ¼ mean cell
concomitant hemostatic defect due to dysfunctional platelets
volume; AT III ¼ antithrombin III
(uremia) or thrombocytopenia (such as aplastic anemia). The
temperature of the environment should be controlled for patients
with temperature-sensitive hemolysis. In patients with combined
Table 17.2 Common coagulation studies and findings
cytopenias (thrombocytopenia and neutropenia), consideration
in factor deficiencies16,17
should be given to appropriate interventions such as antibiotics,
or transfusion of specific products, such as platelets.
Factor deficiency PT aPTT TT

prolonged a prolonged a
I prolonged
Thalassemias and hemoglobinopathies
II prolonged may be prolonged normal
V prolonged may be prolonged normal
Inherited abnormalities of hemoglobin synthesis (thalassemias)
VII prolonged normal normal
or structure (hemoglobinopathies) are important from the per-
VIII normal prolonged normal
spective of the fetus and mother.29 Inherited abnormalities of
VWF normal prolonged normal
hemoglobin structure or synthesis may produce asymptomatic
IX normal prolonged normal
maternal anemia or lead to severe complications with increased
X prolonged prolonged normal
perinatal morbidity and mortality.30 For practitioners caring for
XI normal usually prolonged normal
women with a hemoglobinopathy who are in the early stages
XII normal prolonged normal
of pregnancy, it is important to discuss their need or desire for
XIII normal normal normal
prenatal diagnosis.30 In patients with ongoing chronic extravas-
cular hemolysis and ineffective erythropoiesis, iron overload is an
a
Less sensitive than thrombin time
important and usually avoidable complication. Thus, iron sup-
PT ¼ prothrombin time; aPTT ¼ activated partial thromboplastin
plementation in pregnancy should be withheld pending review
time; TT ¼ thrombin time
of the serum ferritin. Supplemental folic acid is essential in all
patients with these syndromes, due to the extra demands placed
on the marrow in pregnancy.
of the anemia on maternal and fetal well-being. An understanding
Thalassemia
of the pathophysiology of the anemia, inheritance patterns, and
The thalassemia syndromes are a group of inherited disorders that
other mechanisms of involvement of the fetus is essential.
lead to quantitative defects in the synthesis of globin chain sub-
Transfusion of red blood cells (RBCs) is only one potential inter-
units.29 For example, there is deficient production of the alpha-
vention and other therapeutic maneuvers should be weighed
globin chain in alpha-thalassemia and of the beta-globin chain in
against the risks associated with transfusion. In most patients,
beta-thalassemia, the two most common thalassemias seen in
particularly those with long-standing anemia, there is good
North America. The majority of patients with thalassemia have a
physiologic compensation in the mother and expectant manage-
benign carrier state (heterozygous beta thalassemia and the 2 gene
ment is appropriate. The use of erythropoietin in pregnancy is
deletion of alpha thalassemia) and these usually present as a mild
still controversial, with numerous case reports of its use in



294
Chapter 17


anemia in early pregnancy. Most follow a similar pattern to their the degree of hemodynamic compensation with regard to the
nonthalassemic counterparts, with the physiologic anemia of chronic anemia, its relative oxygen-carrying capacity, and its
pregnancy causing a drop in hemoglobin, which is progressive relationship to anesthesia. There is no specific contraindication
until the middle of the last trimester. The nadir of the hemoglobin to the use of a particular anesthetic technique. However, in the
will be significantly below the normal range for pregnancy, but severely anemic patient, narcotic analgesia for labor is relatively
these patients usually compensate well for the degree of anemia. contraindicated due to the increased risk of hypoxemia, and,
The 3 gene deletion state of alpha thalassemia (hemoglobin if used, oxygen saturation should be monitored and oxygen
H disease) is usually a mild to moderate hemolytic anemia in supplementation provided, if required. There are risks and bene-
the nonpregnant state, associated with splenomegaly and chronic fits to general and regional anesthesia for C/S. Careful attention
anemia. By the third trimester, some patients with this disorder must be paid to fluid balance.
may be symptomatic from anemia. Fetal well-being and growth There is one report of successful intraoperative blood salvage
should be followed carefully, and either evidence of compromise in a woman with placenta accreta and b-thalassemia intermedia
who refused transfusion of blood products.34
of the latter or significant symptoms in the mother may be an
indication for transfusion.
Sickling syndromes
There is limited experience with patients who have the most
severe form (homozygous state) of b-thalassemia in pregnancy. Of the clinical sickling disorders, Hb SS and Hb SC disease have the
Many have symptomatic hemosiderosis by the time they reach most impact in pregnancy. Anemia is common and, as there is an
increased risk of infection and vaso-occlusive crises,29,35,36 fre-
the childbearing years with associated delayed sexual develop-
quent assessment is required throughout pregnancy.29,30 There is
ment and cardiomyopathy. Fourteen pregnancies in nine
patients with homozygous b-thalassemia are reported in the an increased incidence of IUGR due to vaso-occlusion of placental
literature.31 Obstetric management was complicated by severe vessels.29 In a cohort study of women with Hb SS disease there was
an increase in early fetal loss.37 The use of prophylactic red cell
anemia, chronic hypoxia, and myocardial hemosiderosis from
iron overload. Cardiac dysrhythmias and congestive heart failure transfusion to maintain Hb A levels above 20% to minimize sickling
are common in this setting and are aggravated by the physiologi- is controversial due to the risk of transfusion transmitted infec-
tion.29,38,39 Some recommend transfusion only in those patients
cal changes of pregnancy. Fetal problems included fetal loss,
who develop complications during pregnancy.39 There is evidence
preterm labor, and intrauterine growth restriction (IUGR).
Another rare, reported complication in a pregnant woman with to suggest that, in patients who receive transfusion, the use of
thalassemia is spinal cord compression by extramedullary hema- leukodepleted red cells reduces febrile transfusion reactions
topoiesis.32 Treatment with blood transfusion resulted in a com- and viral transmission but no data prove a particular benefit.40
plete recovery. Bone marrow transplantation is being used to Maternal mortality in sickling disorders is generally due to septi-
treat this disorder and there is one report of a successful preg- cemia, thromboembolism, or cardiac failure after a hemolytic cri-
nancy following this procedure.29 sis.35 Chronic lung disease, secondary to obliteration of pulmonary
In a population-based study, pregnancy associated with thalas- arterioles and interstitial fibrosis, has been reported and may lead
semia minor was uneventful, other than for a high rate of IUGR.33 to pulmonary hypertension and right heart failure.41
Other sickling syndromes are milder with improved maternal
Hemoglobinopathies29 and fetal outcome. Hb SD disease is rarer than Hb SS but maternal
The homozygous states for hemoglobin C (a2/bc2) and E (a2/be2) are and fetal outcome is generally better. The combination of Hb S and
relatively benign conditions that may present clinically as chronic Hb F does not generally produce clinical problems. Hb E when
hemolysis. Such patients behave in pregnancy as any patient with combined with Hb S produces mild disease. Sickle cell trait is the
chronic hemolytic anemia, with increased demand for the nutri- heterozygous form of sickle cell disease with a hemoglobin pheno-
tional building blocks used for erythropoiesis. Individuals with type AS. It is benign with most patients being asymptomatic.
these disorders are susceptible, although rarely, to a number of However, such patients will still have increased demands for ery-
acute crises: megaloblastic crisis from inadequate folate supple- thropoiesis in pregnancy and supplemental folic acid is essential.
mentation, and aplastic and hypersplenic crises, which may follow
acute viral illness. These patients may present with combined
Anesthesia and the sickling syndromes
abnormalities particularly in association with the thalassemias.
Some combinations are beneficial in terms of the severity of anemia Anesthetic management aims to prevent sickling (see Figure 17.1).
(for instance, patients with beta-chain hemoglobinopathies gener- As sickling tends to occur under conditions of stasis, hypothermia,
ally do better than those with alpha-thalassemia trait) and others acidosis, and hypoxemia, anesthetic management should attempt
to avoid these.42 Areas of anesthetic controversy in sickle cell
detrimental, with a more severe clinical course.
disease include use of direct intra-arterial pressure monitoring in
preeclamptic patients (stasis from a noninvasive blood pressure
Anesthesia in the thalassemias and
cuff vs. risk of vaso-occlusion), regional versus general anesthesia
hemoglobinopathies
(generally accepted that regional is best although some suggest
Anesthetic concerns relate to the underlying cardiac status in the otherwise) and use of prophylactic blood transfusion (possible
improved outcome vs. risk of disease).42
setting of severe forms of thalassemia and, more commonly, to



295
5 Other disorders


during C/S in a patient with sickle cell trait.49 Death was attributed
to severe, concealed aorto caval compression: such that once it
was relieved a large volume of hypoxemic, acidotic blood was
returned to the circulation causing cardiac arrest.49 In another
report, a parturient with Hb SS disease developed progressive
neurologic symptoms post-C/S under spinal anesthesia. Initial
symptoms were attributed to vasoocclusive pain crises. However,
progression of symptoms suggested a pulmonary embolus, foll-
owed by bilateral motor and sensory deficits in a T11-S2 distri-
bution. The woman received anticoagulation following a normal
MRI scan and she made a full recovery.50 There is one report of
the use of an epidural colloid patch in a woman with Hb SS
disease who developed a postdural puncture headache following
spinal anesthesia. The authors were reluctant to do an epidural
blood patch for theoretical safety concerns, including a local
inflammatory reaction leading to activation of the coagulation
cascade and a risk of a medullar vasoocclusive crisis.51
Figure 17.1 A typical peripheral blood smear from a patient with sickle cell
There are two case reports of pheochromocytoma associated
disease demonstrating numerous sickle cells and a rare target cell. (See color
with sickle cell disease.46,52 In one case, the woman had a com-
plate section.)
bined C/S and excision of the pheochromocytoma under general
anesthesia.46 Prior to that surgery she had an exchange trans-
Epidural analgesia has been used for labor analgesia as well
as for control of the pain during sickle cell crisis.43 There are fusion to increase her levels of hemoglobin A. In the second
case where a pheochromocytoma was suspected, the woman
two reports of a sickle cell crisis in previously asymptomatic
had a C/S under combined spinal“epidural anesthesia followed
parturients with sickle cell disease; one was attributed to induc-
by removal of the pheochromocytoma five months later.52
tion of labor and the other to stress during labor. Both received
neuraxial analgesia for the management of pain.44,45 Shivering
increases oxygen consumption and may be detrimental to the
Hemolytic anemias
patient with sickle cell disease. Efforts should be made to limit it
by using warm intravenous fluids and possibly forced air warm-
Hemolytic anemias are classified as inherited or acquired. Of the
ing devices and by keeping the environmental temperature warm.
inherited group the most common are secondary to:
Measurement of oxygen saturation during labor and delivery will
 membrane disorders making the red cell less flexible in the
guide the use of supplemental oxygen.
microcirculation and, thus, susceptible to hemolysis
Regional and general anesthesia are acceptable for C/S,46,47
 metabolic abnormalities, which increase sensitivity to oxidant
although a review of surgery in sickle cell disease found that sickle
stress. Abnormal hemoglobins may make the RBC susceptible
cell disease-related postoperative complications were more
to hemolysis.
frequent in Hb SS patients who received regional anesthesia.48
Acquired disorders causing RBC hemolysis fall into two main
The authors postulated that the results could have been affected
groups:
by the fact that C/S is more commonly performed under regional
 those related to immune-mediated hemolysis
anesthesia and might be associated with more complications
 those associated with mechanical hemolysis due to microan-
than other surgery.
giopathy or other uncommon mechanical stresses (mechanical
Principles of anesthetic management include maintenance of
hemolysis related to artificial heart valves).
intravascular volume (crystalloid), supplemental oxygen to avoid
Hemolysis can occur in the intravascular space causing release
sickling from hypoxia, avoidance of acidosis, adequate left uter-
of free hemoglobin with resulting hemoglobinuria and hemosi-
ine displacement, maintenance of normothermia, and preven-
derinuria, or more commonly extravascularly in the reticulo-
tion of peripheral venous stasis. The above principles apply to all
endothelial (RE) system primarily of the liver and spleen. Common
patients with any capacity for sickling, including the heterozy-
laboratory parameters of ongoing chronic hemolysis include a
gous Hb S carrier state. In the more severe disorders, especially
raised reticulocyte count, increased lactic dehydrogenase
Hb SS, transfusion of warmed RBCs to maintain oxygen-carrying
(LDH), increased unconjugated bilirubin, and, in specific disor-
capacity and increase the blood content of Hb A, when appro-
ders, morphologic abnormalities on the peripheral smear.
priate, is the other parameter to be considered, although this is
controversial.42 Furthermore, as these patients are at risk of high
Inherited hemolytic disorders
output cardiac failure, some may require more invasive monitor-
Hereditary spherocytosis This autosomal dominant disorder
ing. Oxygen saturation monitoring should be continued during
has an incidence of 200“300 per million population and is the
the postoperative period as hypoxia may occur.
most common membrane disorder. The pathognomonic feature
Complications from anesthesia in patients with sickle cell trait
is the presence of spherocytes in peripheral blood associated with
are rare. There has been one case of an intraoperative death



296
Chapter 17


increased osmotic fragility of red cells on special testing in the Thus, these patients may not have splenomegaly. They do not
laboratory. As a result of increased destruction of the abnormal have spherocytes on a peripheral smear but show reticulocytosis,
cells in the RE system, these patients commonly present with raised LDH and bilirubin, and increased hemosiderin in the
anemia, splenomegaly, and jaundice. Splenectomy is curative, but urine. This condition is rare in pregnancy, and does not respond
because of the usually mild nature of this disorder, many patients well to corticosteroids. Transfusion can be problematic and the
do not undergo splenectomy.53 The diagnosis may be made during use of a blood warmer and maintenance of a warm environment
pregnancy,54,55 and although there are reports of hemolytic crises is critical. Since IgM antibodies do not cross the placenta, fetal
during pregnancy most patients tolerate pregnancy well.56,57 involvement does not occur.

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