On a previously quiet Monday afternoon I received a call from the OB floor. "we are going for a stat c/s" was the report given by the nurse. I headed immediately towards the OB OR. I encountered the patient at the elevators leading to the 6th floor. I breifly got a history from the nurses accompanying the patient. She was 36 years old at 36 weeks gestation. She was experiencing brisk vaginal bleeding associated with severe abdominal cramps and pain. The ambulance decided to divert to our hospital because of the urgency of the situation. She was wheeled straight to the OR and hooked up to monitors. I found out that she had a history of hypertension taking Labetalol, w/ NKDA. She was also known to have a placenta previa w/ possible accreta. She was scheduled by her regular obstetrician to undergo a planned cesarian section and hysterectomy a week or so.
Preinduction VS: BP 120/60 HR 110 RR: rapid sats: 98%. Pt expressing pain and is anxious.
Induction is with ketamine 100mg, fentanyl 50 mcg, sux 90 mg all in rapid sequence with cricoid pressure. After incision, the infant was delivered in 1 minute, and is not in distress.
The patient tolerates induction, has 2 IV lines (20G L and 18G R). Within 5 minutes of induction the plethysmographer tracing goes flat and no blood pressure is able to be recorded. 3 mg of phenylephrine is given IV and the blood pressure returns to 90s/40s. The patient is not typed or crossed so type 0 negative blood is procured on an emergent basis and 2 units of O- PRBCs are given over 20 minutes. A R IJ central line and L rad arterial line are placed with some difficulty. Hemostasis is obtained within 10 minutes of incision. The patient experiences only two more episodes of severe hypotension (30's/10's) and (50's/20's) both treated with epinephrine 0.5 mg bolus. A hysterectomy is performed, ancef 1 gm is given IV, versed is given 2 mg to prevent recall along w/ scopolamine 0.4 mg IV. The patient is intermittent run on 50% nitrous oxide and Desflurane depending on blood pressures. The patient makes 200 mL's of urine for the case, receives 3.5 L crystalloid, 2 u PRBCs (O-), 500 mLs hespan, and EBL is 1500 mL. During the case it is discovered that from faxed medical records she is A- and the specimen states that she has antibodies. The patient remains intubated and is transferred to the ICU. Because she is starting to develop hypotension again, the decision is made to transfuse her units of blood, this time A- matched blood. A Hg drawn after her first two units is 7.9 g/dl. The patient did continue to have brisk bleeding from the vagina immediately after surgery, but this was controlled and no oozing occurred from her central line site or arteral line site. After surgery her PTT came back at >200s (significantly prolonged), however, her fibrinogen level was only mildly low with a normal PT and INR. Upon arrival to the ICU she was 34 C.
This represents a case of severe maternal hemorrhage associated with placental abruption and placenta increta (discovered at operation). Placental abruption is not uncommon occurring in 1/100 to 1/150 deliveries, but is not commonly as severe as in this particular patient. It carries of perinatal mortality of 20%, so rapid delivery is often mandated for fetal and maternal salvage. This patient did have a few risk factors for abruption including advanced maternal age (36 y/o) and history of hypertension. Other risk factors, African american race, multiparity, cigarette smoking and cocaine abuse were either negative or unknown. Patients who experience abruption of the placenta are at high risk for DIC as demonstrated by Gilabert and colleagues in 1985. They explained that large venous sinuses beneath the abrupted placenta could allow thrombopastic material to enter the maternal circulation. Fortunately, in this patient no signs or evidence of DIC presented itself.
Treating hemorrhagic shock typically involves ensuring the maintenance of DO2. Since DO2=CO X (Hb x 1.34 x SaO2) + (PaO2 x 0.0031), maintaining an adequate cardiac output and Hb level are the principal factors. Secondarily, O2 extraction at the tissue level can compensate for decreased DO2. PaO2 in this regard is insignificant and the saturation is usually not so low as to be rendered clinically important in this regard. Initially, colloids and crystalloids should be utilized to maintain cardiac output, which in healthy individuals will easily compensate for a lowered Hb and in some cases DO2 may be elevated after hemorrhage compensated by crystalloid infusion due to improved rheologic effects.
In our case it was decided to transfuse unmatched type O negative blood. According to the ASA committee on transfusion medicine (4th edition), it is recommended to give uncrossmatched type 0 negative blood only when the patient is experiencing signs of organ dysfunction related to decreased O2 delivery. In males and post menopausal females, it is recommneded that type O positive be used. Only 20% of the population is considered Rh -, and therefore, type O Rh-negative blood is less common and should be utilized only when necessary. The concern is that giving a female who is still may yet have children in the future, you may cause her to develop anti-D antibodies (or antibodies against the D antigen in the Rh system). This is referred to as sensitization. In other words, giving type O-positive blood is unlikely to cause any reaction at all to any one unless they are Rh-negative and already sensitized (unlikely unless they have had previous transfusions or pregnancies). In historical studies, patients will develop anti-D antibodies about 80% of the time if they are Rh-D negative and are exposed to Rh positive blood. However, recent studies in trauma victims who require massive ressuscitation with fluid and blood products have found that sensitization occurs in only 30% of these individuals. It is hypothesized that the intense stress response brought on by the trauma or illness suppresses the normal immune response and reduces the likelihood of sensitization. In our case, our patient was required to have a cesarian section followed by hysterectomy and furthermore had received Rhogam. Therefore, O Rh positive blood would probably have been a better choice in retrospect so as to conserve the more rare type O Rh-negative blood. Some may question this approach given that our patient had received Rhogam which acts by destroying fetal RBCs that cross into the maternal circulation. In this case, one might suppose that the Rh immunoglobulin still circulating in the mother, might destroy RBCs transfused if they were type O positive. The standard dose is 300 mcg, and this only destroys about 15 mL of RBCs.
One other caveat in our patient is that she was positive for antibodies, although nothing more was specified. Our pt was type A Rh-negative. This indicates that she most likely received Rhogam (Antibodies) to prevent sensitization of the mother to fetal Rh-positive antigens, thus causing risk in future pregnancies for hemolytic disease of the newborn, a disease in which the fetus' RBCs are attacked as foreign by antibodies that manage to cross the placenta from the mother. Receiving Anit-D antibodies (Rhogam) will cause a subsequent type and screen to show antibodies, but they are unlikely to cause problems. Regardless of whether she had actual antibodies on the type and screen or not, given the patient's dire clinical situation, an emergency transfusion was indicated.
In our patient a sample was immediately sent to the blood bank to do a type and screen. However, in the mean time, 2 units of type O negative blood was given. The type and screen took 15 minutes and a electronic match was performed so that we had type A negative blood in only 30 minutes. A question was raised as to whether the patient could receive her type specific blood now after having received two units of type O negative blood. According to Yao and Artusio textbook, referring to published ASA guidelines, it is recommended to continue using type O negative blood if whole blood is given after only two units. However, whole blood is rarely used today, and the amount of serum in packed cells is very small and quickly diluted into the volume of blood in the patient. Therefore, the recommendation is to switch back to type specific blood even after several units of type O negative packed RBCs. At our institution, the blood bank does not specify a cut off for the number of type O negative blood given before we are unable to switch back to type specific blood.
When a type and screen is done, the screen portion refers to the mixing of the patient's serum with a commercially available donor RBC reagents. RBC surfaces contain up to 300 different antigens. In patients who have not been exposed to blood (transfusion or pregnancy), it is very unlikely that there will be unanticipated antibodies. In these cases, autoantibodies are the most likely culprit of a postive antibody screen. However, it is important to send the blood in a purple top tube (which contains EDTA to prevent a false positive). Certain medications may also result in a false positive: Ibuprofen, penicillins, cephalosporins, tetracyclines, antihistamines, sulfonamides, levodopa, methyldopa are a few of the most notorious ones. Furthermore, an autocontrol may be run and result in a positive. This test reacts the patients serum against their own RBCs and if positive should be followed by a direct antiglobulin test. The Type and Screen takes about 10 minutes. Not all antibodies are clinically relevant, however, when the screen comes back positive for antibodies, i.e., the patient's serum contains antibodies that might cause a hemolytic reaction to a transfusion, the antibody type is not known until further investigation. Clinically significant antibodies are: Anti-A,B, D, C, E, c, e, Fya, Fyb, Kell, Jka, Jkb, S, and s.
In summary, in an emergency use type O Rh positive blood unless you are transfusing a female is might become pregnant in the future; in this case use the more rare blood type O Rh-negative. In an emergency, always send a type and screen even if you are planning on using type O blood and switch to type specific blood as soon as possible. If the screen comes back positive for antibodies, a brief discussion with the lab is in order to find out if this occured at room temperature or at 37C (temp the screen should be done at). In some cases a false positive will occurr (due to medications or treatment received as in our patient Rhogam). Armed with this information, a benefit to risk analysis should ensure quickly to determine whether or not a transfusion is merited in the face of a known positive screen for antibodies.