Severe Pre-eclampsia vs Untreated HTN

[anes]

34 y/o G6P4 all by c-section, 35 weeks gestation, pre-eclampsia with 2 previous pregnancies, meth abuse, morbid obesity (bmi 55), severe osa, pulmonary htn, chronic hypertension (controlled with labetalol). Can't recall why she presented but was found to be pre-eclamptic (mild proteinuria, no visual symptoms, no headaches, normal platelets, normal LFTs, mildly elevated pressures 140s/90s). Admitted for supervision of high risk pregnancy, and plan for repeat c-section.

She was kept in the hospital for 3 days and her anti-hypertensives were held (for whatever reason, possibly oversight on part of the obstetrics team). Patient states that without labetalol her SBP would routinely reach 180s. During these three days her HR and blood pressure slowly crept up until they were hovering around 160's systolic. All of the other parameters were unchanged, FHR was reassuring. The ob/gyns decided to call this severe pre-eclampsia and started a mag infusion. They also decided that after patient met NPO criteria (1 am) that they would proceed with c-section.

So to get to my question. Why is this considered severe pre-eclampsia and not just pre-eclampsia with untreated chronic hypertension? I mean, she's a known severe hypertensive and isn't receiving treatment.

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[THP]

It's hard to say. It can be difficult to diagnose pre eclampsia in these patients, especially if they have some baseline renal dysfunction from their chronic HTN. Did she have a baseline 24hr urine total protein or protein/Cr ratio to compare? It may be she has been non-compliant and they are looking for any excuse to get her delivered. 35 weeks sounds like a great time for delivery to me. She sounds like a ticking time bomb for something awful to happen.

 

[anes]

I don't recall if she had baseline labs (my guess would be no). I agree that it was a good time to deliver her (35weeks). But without fetal distress, true severe pre-eclampsia, hellp, or eclampsia is there any reason to do this case at 1 am?

I'm asking from the perspective of an anesthesiologist. She's obviously extremely high risk from our standpoint. The difference between the type of help available at 1am versus 8am is night and day. We refused to do this case at 1 am (unless they declared it an emergency) and delayed until morning. The patient and the baby did well. Needless to say, the ob/gyns were not happy with us.

Also, FWIW, the patient stated that she was rigid in taking her beta blocker because of previous pre-eclampsia. She also said to me "I don't know why they haven't been giving me my labetalol since i've been here".

 

[Global Disrobal]

I can't give you a clear cut answer from the details presented as I don't think you have the full story at hand especially the pulmonary hypertension piece, which would in itself present a higher risk to her than the superimposed preeclampsia. With that said, we (as obstetricians) predominantly refrain from calling difficult surgeries in the middle of the evening, but there are times (as I'm sure you'd understand), where you much rather operate on the difficult patient under a controlled and stable condition than an emergent one (e.g. eclampsia, cardiopulmonary arrest). Nevertheless, it is hard to gauge why the asked for the emergent 1 AM delivery; but it appears that you don't know either. I would recommend discussing the decision making process with the attending obstetrician as a team so that all parties can voice their concerns.

 

[anes]

I can't give you a clear cut answer from the details presented as I don't think you have the full story at hand especially the pulmonary hypertension piece, which would in itself present a higher risk to her than the superimposed preeclampsia. With that said, we (as obstetricians) predominantly refrain from calling difficult surgeries in the middle of the evening, but there are times (as I'm sure you'd understand), where you much rather operate on the difficult patient under a controlled and stable condition than an emergent one (e.g. eclampsia, cardiopulmonary arrest). Nevertheless, it is hard to gauge why the asked for the emergent 1 AM delivery; but it appears that you don't know either. I would recommend discussing the decision making process with the attending obstetrician as a team so that all parties can voice their concerns.

The reason for the urgent delivery was that her SBP hit the threshold of 160 mmHg (which would make her severe pre-eclampsia). No other reason whatsoever. The reason that they wanted it done at 1 am is because that is when she would NPO for 8 hours. Her pulmonary hypertension was mild, and likely secondary to chronic meth use. Either way, the pulm htn was relatively low on our concerns for her anesthetic.

My main question was... how do you differentiate severe pre-eclampsia from untreated chronic hypertension? Couldn't a patient have mild pre-eclampsia, and the blood pressure elevation be due to withholding anti-hypertensives? Would somebody with blood pressure elevation secondary to chronic hypertension (superimposed on mild pre-eclampsia) be at higher risk than somebody whose blood pressure was solely because of preeclampsia? Are there actual guidelines to make the decision?

 

[Global Disrobal]

By definition and standard practice, superimposed preeclampsia is severe in behavior and treated as such, whereas de no preeclampsia (in an otherwise non-hypertensive patient) can be classified as mild or severe. As I mentioned earlier, the only way to answer your question regarding the diagnosis at hand would be to have the full presentation at hand, not your cross section snapshot. You are correct in that systolic hypertension can be simple hypertension exacerbation, but more information is needed to make the determination including the pulse pressure and volume status.

With respect to the pulmonary hypertension, I'm shocked to hear anyone, especially one from anesthesia consider pulmonary hypertension (PHTN) as "low concern." Yes, many of us consider mild PHTN diagnosed in the pregnancy a possible false positive due to inherent blood viscosity changes of pregnancy, but with legitimate PHTN (non-idiopathic) I would still worry more about that than the hypertension.

Lastly, with respect to your question for management of various forms of preeclampsia, you can look up the latest SMFM clinical guidelines (https://www.smfm.org/publications/166-hypertension-in-pregnancy) or any of the expert opinions by Baha Sibai.

 

[anes]

By definition and standard practice, superimposed preeclampsia is severe in behavior and treated as such, whereas de no preeclampsia (in an otherwise non-hypertensive patient) can be classified as mild or severe. As I mentioned earlier, the only way to answer your question regarding the diagnosis at hand would be to have the full presentation at hand, not your cross section snapshot. You are correct in that systolic hypertension can be simple hypertension exacerbation, but more information is needed to make the determination including the pulse pressure and volume status.

With respect to the pulmonary hypertension, I'm shocked to hear anyone, especially one from anesthesia consider pulmonary hypertension (PHTN) as "low concern." Yes, many of us consider mild PHTN diagnosed in the pregnancy a possible false positive due to inherent blood viscosity changes of pregnancy, but with legitimate PHTN (non-idiopathic) I would still worry more about that than the hypertension.

Lastly, with respect to your question for management of various forms of preeclampsia, you can look up the latest SMFM clinical guidelines (https://www.smfm.org/publications/166-hypertension-in-pregnancy) or any of the expert opinions by Baha Sibai.

How would the diagnosis of mild pulmonary hypertension change my management of a patient? I wouldn't be more likely to place a central line or swan. Somebody with pulm htn the goals are to pretty much the same as somebody without pulm htn (maintain normoxia, maintain normocarbia, maintain normal pH, avoid hypovolemic, and maintain normal blood pressure). This patient isn't on epoprostenol, sildenafil, calcium channel blockers, so the likelihood of dramatic right heart failure is low. If she crashed, we always have Transesophageal echo available. If her PA pressure is significantly elevated or shows signs of RHF we have milrinone and NTG available in our pyxis. It's nice to know that she has mild pulm HTN, but again it doesn't change my management.

Now if she had severe pHTN (on infusions) the management may change.

 

[Global Disrobal]

Easy tiger! No one is challenging your knowledge of pulmonary hypertension management... If you read my posts (without getting defensive) again, what I'm telling you is that 1) you don't have the full picture based on what you're presenting, 2) the pulmonary hypertension would be more of a concern in this patient than the hypertension despite how comfortable you seem to feel with it in a pregnant woman in as many co-morbidities as you list, and 3) it's truly hard to gauge why they elected to deliver at 1 AM with what little information you're providing.

If you came to this forum to get some validation for your refusal to deliver at 1 AM, then I'm sorry as I can't give you that "make me feel good" credit. Furthermore, I've worked with numerous anesthesia staff in residency, fellowship, military, and practice, and I can count on one hand the number of times that the delivery has been refused by anesthesia and all of those were due purely to staffing not disagreement with obstetric management. As I said before, go talk to the OB attending(s) on that evening, and simply ask why they wanted to deliver at 1 AM. It'll get you a much more valid answer than this forum.

 

[anes]

Easy tiger! No one is challenging your knowledge of pulmonary hypertension management... If you read my posts (without getting defensive) again, what I'm telling you is that 1) you don't have the full picture based on what you're presenting, 2) the pulmonary hypertension would be more of a concern in this patient than the hypertension despite how comfortable you seem to feel with it in a pregnant woman in as many co-morbidities as you list, and 3) it's truly hard to gauge why they elected to deliver at 1 AM with what little information you're providing.

If you came to this forum to get some validation for your refusal to deliver at 1 AM, then I'm sorry as I can't give you that "make me feel good" credit. Furthermore, I've worked with numerous anesthesia staff in residency, fellowship, military, and practice, and I can count on one hand the number of times that the delivery has been refused by anesthesia and all of those were due purely to staffing not disagreement with obstetric management. As I said before, go talk to the OB attending(s) on that evening, and simply ask why they wanted to deliver at 1 AM. It'll get you a much more valid answer than this forum.

My question really had nothing to do with the delivery at 1 am. That was just some background. My question was specifically regarding diagnosing severe pre-eclampsia vs mild preeclampsia with untreated chronic htn.

 

[THP]

If you have pre-existing hypertension and then develop pre-eclampsia (superimposed) we don't distinguish between mild and severe because it is considered severe by convention. See Global Disrobal post above.

Superimposed preeclampsia is not always a cut and dry diagnosis. The best way to figure it out is if there is new development of proteinuria. Unfortunately life is not always that simple. Current trend is for proteinuria to be less of a defining characteristic but rather looking for "severe features". Lab abnormalities, neurologic symptoms, uncontrollable HTN, etc. Of course fetal well being is also an important consideration.