Book 4, case 1-Sickle cell and obstetrics

Question 1

Why do patients with sickle cell take hydroxyurea?

Answer 1

administered to reduce the number of sickle cell
crises via its ability to increase circulating fetal hemoglobin, which, in turn, reduces
the rate and extent of HbS sickling.

Question 2

Pathophys of sickle cell:

Answer 2

Valine for glutamic acid in beta chains of hgb=HGb s. Hgb s molecules can polymerize making a sickled shape=hemolyiss and ischemic end organ injury

Question 3

Why doesn’t sickling happen always in venous blood?

Answer 3

Even though HbS starts to polymerize at PO2 of 50 mmHg, this is time dependent-it transitions to lungs where oxygenation reverses that.

Question 4

What is aplastic crisis? How do you treat it?

Answer 4

bone marrow suppression secondary to
infection (typically Parvovirus B 19) or folate deficiency leads to decreased red blood
cell production leading to a profound anemia. Treatment: correction of folate deficiency and admin of blood until bone marrow suppression resolves (4-7 days)

Question 5

EValuation of sickle cell pt and a pregnant sickle cell pt at that:

Answer 5

Full H&P 
Questions about frequency of crisis 
INquire about hx of acute chestsyndrome 
Examine for signs of infxn 
evaluate volume status 
if SOB: CXR

Question 6

What is an exchange transfusion, and would you do it in preggo sickle cell pts?

Answer 6

The procedure involves slowly removing the person’s blood and replacing it with fresh donor blood or plasma-nah, I wouldjust give a transfusion of leukocyte reduced hemoglobin S free red blood cells to achieve a Hct of 30% (leukocyte reduced)

Question 7

If pt has low plt (82k for example) but is huge and possible difficult airway-and you wanna do regional-what are you going to do to prepare-exam wise?

Answer 7

I would evaluate the patient for signs of coagulopathy (bruising,
mucosal bleeding, bleeding at IV sites), make sure that there was not an unacceptable
downward trend in her platelet level, and judiciously provide fluids for volume
replacement (overaggressive fluid administration risks pulmonary and cerebral edema
in the setting of severe preeclampsia).
Postoperatively, I would ensure adequate platelet levels and allow for complete
resolution of motor and sensory function prior to removing the neuraxial catheter (to
allow for better detection of the change in motor or sensory function associated with
epidural or spinal hematoma formation). Following the removal of the catheter, I
would order hourly neuro-checks for 12 hours, to more quickly identify the signs and
symptoms of epidural or spinal hematoma

Question 8

Shortly after achieving adequate levels with the epidural, the case begins and the
baby is quickly delivered. A few minutes after delivery, the mother complains of
difficulty breathing and then begins seizing. What do you think is going on?

Answer 8

The timing of her dyspnea and seizure, occurring shortly after delivery
of the baby, is consistent with amniotic fluid embolism. However, I would also
consider that her symptomatology might be the result of local anesthetic toxicity (this
possibility should be considered in any situation where a patient experiences an
altered mental state, neurologic symptoms, or cardiovascular instability following the
administration oflocal anesthetic for regional anesthesia), preeclampsia/eclampsia
(the increased capillary permeability associated with preeclampsia could lead to
pulmonary edema and dyspnea), or her sickle cell disease (vaso-occlusive crisis can
lead to dyspnea and/or seizures).

Question 9

Signs and symptoms of amniotic fluid embolism?

Answer 9

The first or early phase consists of pulmonary hypertension (secondary to
pulmonary vasospasm), hypotension (secondary to right heart failure), hypoxia
(secondary to ventilation-perfusion mismatching), seizure, and cardiac arrest. For
those who survive the first phase, the second phase consists of left ventricular failure

Question 10

IF you have to leave the catheter for a long time for some reason:

Answer 10

I would ensure that a sterile occlusive dressing

was placed over the catheter insertion site and assess the patient daily for signs or
symptoms of infection, such as fever, backache, headache, erythema, and tenderness
over the insertion site.

Question 11

Nitrous oxide in sickle cell pt who recently had eye surgery:
So if you can’t supplement with nitrous in uterine atony, then what:
How long to avoid nitrous after eye surgery? How long to avoid nitrous after the other eye stuff?

Answer 11

NO.I would want to continue administering 100% oxygen to minimize the
amount of deoxygenated hemoglobin S, thereby reducing the risk of significant
sickling.
Secondly,this very soluble gas could result in the expansion of the intra-vitreal
bubble, leading to increased intra-ocular pressure, central retinal artery occlusion, and
retinal and/or optic nerve ischemia.

If you cant’ supplement with nitrous in uterine atony-reduce inhalational agent to less than 0.5%, administer 100% O2 and supplement with narcotics

Avoid nitrous for 7-45 days after eye surgery
Particularly dangerous with sulfur hexafluoride and perfluoropropane
Avoid for 15 minutes before intraocular gas
Avoid for 7-10 days after sulfur hexafluoride
Avoid for at least a month after perfluoropropane

Question 12

What makes you nervous about nitrous post eye surgeries? Would you feel okay if the surgeon had used air?

Answer 12

B/c we are worried about nitrous oxide expansion of an intra-ocular bubble.
Nitrous oxide should be discontinued 15 minutes prior to the injection of intra-
vitreal gas for retinal detachment surgery.

Nitrous should be avoided for a variable amount of time depending on the type of
gas injected:
o Air - avoid nitrous oxide for 5 days
o Sulfur Hexafluoride - avoid nitrous oxide for 10 days
o Perfluoropropane - avoid nitrous oxide for at least 30 days

Question 13

Is sickle cell disease associated with pulmonary hypertension?

Answer 13

YES

Question 14

Bleeding continues and you institute the massive blood transfusion protocol.
You have given 5 units of PRBCs and 4 units of FFP. The patient’s blood
pressure drops to 78/44 mmHg and is not responsive to additional doses of
phenylephrine. What do you think is going on?

Answer 14

The most likely causes of her nonresponsive hypotension are
inadequate blood or fluid replacement and/or hypocalcemia secondary to massive
blood transfusion (the citrate preservative in blood products can chelate calcium
during massive blood transfusion). However, I would also be considering other
potential causative or contributory factors, such as: ( 1) myocardial depression from
acidosis or anesthesia; (2) magnesium toxicity (vasodilation and myocardial
depression); (3) right heart failure due to the pulmonary hypertension associated with
sickle cell lung disease; (4) transfusion reaction; and (5) pulmonary
thromboembolism.

Question 15

Signs of citrate intoxication:

Answer 15

increased
central venous pressure, narrow pulse pressure, prolonged QT interval, flattened T
waves, widened QRS complexes, and increased intraventricular end-diastolic
pressure.

Question 16

If pt has opioid addiction, reassure them that what:

Answer 16

reassure the patient pre-operatively that her potential

opioid dependence would not deter me from providing adequate pain control post-
operatively; (2) explain to the nurses in recovery that she will likely require

significantly more pain medicine than their typical patient (one of the main risk
factors for inadequate pain control in opioid dependent patients is the biases of
healthcare personnel); (3) supply intravenous or oral opioids equivalent in strength to
her normal daily dose; ( 4) provide epidural morphine, recognizing that higher than
normal amounts may be required to achieve the desired amount of analgesia; and (5)
make 2-3 times the normal amount of anticipated opioids available to her for
breakthrough pain.

Rb: sickle cell patients in pain can lead to sickling!

Question 17

TAP block:

Answer 17

T7-L1: inject local anesthetic in plane between internal oblique and transversus abdominus muscles.

Question 18

Addicted pt says pt comfortable with just epidural morphine-are you d/c scheduled Iv/oral narcotics until pt complaines of pain?

Answer 18

No.I would have the nurse continue the scheduled administration of
systemic opioids in an amount equivalent to her pre-admission dose, and explain to
her that patients who take opioids chronically are at increased risk for perioperative
opioid withdrawal.However, I recognize that there is always a risk of postoperative respiratory
depression with the administration of narcotics for pain control. Therefore, I would
talk to the nurse about the importance of close clinical observation, and order
continuous postoperative monitoring of oxygenation (e.g. pulse-oximetry)

Question 19

What is acute chest syndrome? ANd ehat are you going to do about it/

Answer 19

typically presents with fever, tachypnea, cough, hypoxemia, pulmonary
infiltrate, and chest pain
provide
supplemental oxygen, bronchodilators, incentive spirometry, and chest physiotherapy;
(2) administer antibiotics to cover atypical and encapsulated organisms; (3) ensure
adequate pain control; (4) correct any anemia with simple blood transfusion; and,
depending on the severity of the patient’s condition, (5) consider exchange
transfusion and/or mechanical ventilation.

Question 20

Pt is annoying and says she doesn’t want a pregnancy test-she is breastfeeding and can’t be preggo-wyd?

And then what do you do when you have to get one?

Answer 20

Therefore, I would carefully review my institution’s policy, and assuming there was
no requirement for mandatory pregnancy testing, I would provide informed consent,
have the patient sign a waiver of all legal rights as it pertains to an undetected
pregnancy, and proceed with the case.

If she had to: I would explain to her that given the potential for harmful affects on
the baby’s development and the increased risk for spontaneous abortion or preterm
labor, the facility requires preoperative pregnancy testing prior to elective surgery. I
would further explain that she has every right to refuse pregnancy testing, but the
facility would then be forced to exercise their right to refuse service.

Question 21

Tourniquets in pts with sickle cell?

Answer 21

I would prefer to avoid tourniquet use in this patient with sickle cell
disease because of the regional venostasis, acidosis, and deoxygenation of
hemoglobin that occurs distal to the tourniquet. However, since tourniquets have
been utilized safely in sickle cell patients for up to two hours, I would agree to his
plan if it were necessary for the successful completion of the procedure while trying to prevent things that can contribute to sickling such as: hypoxia, acidosis, dehydration, hypothermia, and hyperthemia