Question index:
Questions received during this symposium have been paraphrased
and the answers submitted by the panelists are presented.

Is the sodium in sodium bicarbonate bad for your blood pressure?
Is the high blood pressure during stress bad for you?
Why is my husband's blood pressure highest in the morning?
How often should I take my blood pressure?
How high does BP have to be to qualify one as hypertensive?
Where can you get blood pressure testing machines?
Can the blood pressure be too low? Mine is 110/65.

Dr. Toto's answers
(Back to question index)

Is the sodium in sodium bicarbonate bad for your blood pressure?
Dr. Toto:
You are right, if you administer sodium bicarbonate, you are taking in sodium. The reason why sodium bicarbonate is administered is that bicarbonate is a base, which is the opposite of an acid. In patients who have kidney failure, their kidneys can't excrete acid normally. As a consequence, acid builds up in the blood. So the sodium bicarbonate is given as an antidote to the acid. Unfortunately, you can't just give bicarbonate. You have to give the bicarbonate with something else. Bicarbonate is a negatively charged substance. Sodium is a positively charged substance. So we don't want to give sodium, but we are stuck. If we are going to give bicarbonate to help treat the acid, we have to give sodium with it because the alternative would be potassium bicarbonate; and potassium, of course, is dangerous for other reasons. So there is an offset if you're being administered a lot of sodium bicarbonate in your diet.

Will that affect the blood pressure? Usually only slightly, if at all. Salt is sodium chloride, and the chloride appears to make the effects of sodium on blood pressure worse than when sodium is given as bicarbonate.

(Back to question index)

Is the high blood pressure during stress bad for you? My doctor says to measure your blood pressure at your highest stress point, and then he wants it down.
Dr. Toto:
As you just said, your blood pressure varies throughout the day. I don't have any scientific basis to say that you should check your blood pressure during your highest stress point because it turns out that if you have kidney disease, even if you are at your lowest stress point, your blood pressure may still not be normal. That is because a lot of patients with kidney disease who have high blood pressure don't have the normal variation in the blood pressure during the day that a normal person does.

The normal variation in blood pressure is such that during the evening, particularly when you are asleep, your blood pressure goes down. It is called nocturnal dipping because the blood pressure is sort of up during the day, and then it dips down at night, and then it comes back up in the morning. There have been over 30 studies done in patients with chronic kidney failure, most on dialysis but many pre- dialysis, where they have attached ambulatory blood pressure monitors to the arm and measured blood pressure continuously for 24 and up to 48 hours. These studies, virtually every one of them, with only one or two exceptions, illustrate clearly that the normal decline in blood pressure does not occur.

The implication is that the overall burden or load of blood pressure to the heart and to the brain and to the kidneys is higher because of that. Even if the blood pressure dips down some, if it doesn't dip down normally, you carry a higher risk. So as far as measuring your blood pressure when you are at your highest stress, and what if it is normal? Then I guess you would say... what would you conclude? That that particular stressful moment wasn't driving your blood pressure up. But it wouldn't exclude it from going up at some other stressful time when you didn't measure it.

Audience member:
But does spiking of blood pressure during the day due to stress damage the kidneys and other organs?

Dr. Toto:
You want to know if the spiking can harm the kidneys? I don't know. I suppose if it is spiked up for minutes, the risk would be low. If it spikes up for hours, maybe that would be injurious. But we don't know the answer to that question.

(Back to question index)

My husband has had a stroke, and I monitor his blood pressure regularly, constantly. Why is it in the morning it is like 176/95 and then during the day it is 135/80?
Dr. Toto:
Is he taking medicine? Yes. It could be due to the type or timing of administration of the medication that he is on. It may be that the blood pressure medication that he is on is not working for a full 24 hours. Ideally if you are hypertensive and you are taking blood pressure medication and it is working the way we want it to, your blood pressure should be normal through the entire time. Now the fact that his blood pressure is higher in the morning and then comes down during the day--I would suspect that is related to that, the timing of his medication. I don't know which ones he is on and when he takes them, but that would be my guess.

Dr. Daugirdas:
Just a clarification. The nocturnal dipping happens like at 3 a.m. in the morning. Usually blood pressure tends to be high in the morning. So if the medications have worn off, that is not that uncommon.

(Back to question index)

How often should I take my blood pressure?
Dr. Toto:
I think that if you are hypertensive, what I mean by regularly is daily. I think that it is hard to do all these things if you are a sick person and you have to take pills and you're trying to work and so forth. What I mean by regularly is I mean daily, at the same time, sort of as a routine thing. And how many times a day you should take your blood pressure we don't know. Should you take it daily for the rest of your life or should you take it daily until your blood pressure is under control and you know your diet is the same and you know you're taking your medicines and then maybe you can go to once a week or once a month or something like that.

I think that it is so important that people who are hypertensive should own a blood pressure machine and they should be able to use it or have somebody else who can use it and that they should measure it daily and make sure that it is staying under control. I think, actually, everybody who is hypertensive should be supplied with one free and learn how to use it. I think it is that important. It is that big of an issue actually in the hypertensive population in general, not just those with kidney disease.

(Back to question index)

How high does BP have to be to qualify one as hypertensive?
Dr. Toto:
The current guideline says that an abnormal elevation in the blood pressure is 140 mm systolic, 140 or greater systolic; or 90 or greater diastolic. Now that is the United State's Joint National Committee's current recommendation. The World Health Organization's definition of high blood pressure is different from that. I think theirs is still higher than that, although I think they are convening to bring it down. Theirs is more like 159 or 160. At least in the renal population, I don't think that anybody would accept that 150-something is normal, especially not in a diabetic.

For reasons of time, I didn't show you other evidence, but there is no question that in the diabetic a systolic blood pressure over 145 is really bad news for their kidneys, and as we discussed, there is evidence in diabetics, especially, with proteinuria, that one needs to lower the blood pressure to the normal range, 120-130/75-80, to get maximum protection of the kidneys.

(Back to question index)

Where can you get blood pressure testing machines?
Dr. Toto:
They are available at pretty much any drug store. I don't know what the drug store chains are here in Canada, but they all sell them. Usually they have an array of them now. There are several different manufacturers. There are even ones that you can put on your finger that will measure blood pressure. The technology is still evolving in this area, but it has gotten a lot better. I think when there is concern about whether or not my machine works, the best way to handle that, and what I tell my patients is: Get the machine, measure the blood pressures, bring the machine with you to my office, and I measure the blood pressure with my cuff on the wall and with their machine at the same time.

Audience member;
Do you recommend any particular brand?

Dr. Toto::
A particular one? No. I don't have any favorites.

(Back to question index)

Can the blood pressure be too low? Mine is 110/65.
Dr. Toto:
That is a really good question. I didn't want to get into that on the curve. That is why I said I was hoping you would bring it up during the discussion. There is evidence in dialysis populations and actually one of the major contributors to this was a Canadian group that showed that in dialysis patients low blood pressure was worse in terms of risk for death in dialysis in patients who had low blood pressure. However, this was believed to be due to the development of heart failure. Heart failure in the dialysis patient is usually associated with low blood pressure, not high blood pressure.

In other words, what I am saying is that low blood pressure as a risk factor for death in those patients was probably actually a marker that the patients actually had disease of their heart, too, that was failing. In terms of is there a blood pressure that is too low for your organs--I think that in somebody who has had a stroke or in somebody who is at risk for falling, and this mostly applies to older people, elderly patients, probably they need a higher systolic blood pressure than 110. But the evidence from studies done recently in a diabetic population, just the general Type 2 diabetics, adult onset diabetic population, shows that when you lower blood pressure down to as low as 110-120 systolic, you continue to have reduced risk of cardiovascular death events.

So what blood pressure is too low? The blood pressure is too low if you are dizzy or having symptoms when you stand up or get out of bed. Move around and you check your blood pressure and if you are symptomatic at the blood pressure level, then I think that is too low. But if your blood pressure is 110 systolic and you are controlled on medications, I don't think it is too low for you.