Would you be so kind and explain to me this intubation and BP?

[Wackie]

---

Members don't see this ad.

I'll present the question first since some of you hate paying attention. 😛
Why would intubation lower BP, and also why does intubation work so well for hypoxia? Do accessory muscle use make the lungs less efficient?

Here's the story (and this was over a week ago, so details are fuzzy):

We get this 72 yr old fellar. He's working hard to breathe, using accessory muscles even while on a mask. He had no interest in talking and would occasionally follow people around the room with his eyes. Most of the time he stared straight ahead. The paramedics got him with 02 sats in the 40's and they managed to get him into the 60's. They gave nitro and the patient had asprin before the paramedics arrived...you know typical stuff for chest pain, sob.

I look at the monitor to jot down his BP and holy moly, it's 220/195 (I do all of the documentation for the doctor). And then something goes wrong with the equipment and we can't get a constant measurement on him. I don't remember what his pulse was. I think he was like 104 or so, but don't count on my memory. The doctor hears fluid in the lungs and gives a little of "this" to try and get fluid out of his lungs as well as a little of "that" to lower his BP (I can't remember the drug names. But you guys are smart fellars so I figure you prolly already know).
He had been released from the hosptial only two days prior with a beautiful chest x-ray. We got another in the ED and it's heart failure times eleventy billion.
The doc gives time for the drugs to work. The lungs sound better and his BP dropped to 185/150-something, but he's still circling the drain. We pull blood gasses on him and they're into the 100's. So, the doc intubates.
It goes smoothly and we walk out. We see a patient and while I pull up labs, the doctor goes to back to see the critical one. Soon, I hear him loudly bitching out the staff over not letting him know his BP dropped to 60, and he drops into a chair and tells the entire story to another doctor standing there.

Why would the BP bottom out after intubation? Why would intubating lower the blood gasses when, by the x-ray, the patient was lucky to have any gas exchange in his lungs regardless?

 

[NinerNiner999]

This sounds like an episode of flash pulmonary edema that was perhaps overzealously treated with nitrates and lasix (both of which can bottom out BP). This, combined with the (hypothetically negligible) effect of paralytics and sedatives for RSI could have resulted in the BP given. Of course, this is based solely on your interpretation of the situation...

 

[ERMudPhud]

A few things in your history are a bit confusing like a BP of 220/195 doesn't sound like a valid BP and "blood gasses in the 100's" doesn't mean much to me unless you are talking maybe about pC02 but I'll try to answer your questions anyway.

Why would intubation lower BP? lots of reasons
1. The drugs we use may lower BP. Propafol is a good example
2. The patient is freaking out because he feels like he is smothering and you've now sedated him taking away the whole freaking out, fight or flight response thus decreasing adrenergic tone
3. Airtrapping in COPD leading to increased intrathoracic pressure, decreased venous return, and dropped cardiac output.
4. Too much PEEP leading to same effect as in 3

Why would intubation raise 02sats in someone whose lungs are already working for crap?
1. You are directly delivering 100% 02 right into the trachea. Something a face mask will never accomplish
2. In CHF positive pressure can counterbalance some of the effects of pulmonary edema
3. In COPD/asthma positive pressure may help stent open the airways

Hope that helps

 

[Wackie]

A few things in your history are a bit confusing like a BP of 220/195 doesn't sound like a valid BP and "blood gasses in the 100's" doesn't mean much to me unless you are talking maybe about pC02 but I'll try to answer your questions anyway.

Why would intubation lower BP? lots of reasons
1. The drugs we use may lower BP. Propafol is a good example
2. The patient is freaking out because he feels like he is smothering and you've now sedated him taking away the whole freaking out, fight or flight response thus decreasing adrenergic tone
3. Airtrapping in COPD leading to increased intrathoracic pressure, decreased venous return, and dropped cardiac output.
4. Too much PEEP leading to same effect as in 3

Why would intubation raise 02sats in someone whose lungs are already working for crap?
1. You are directly delivering 100% 02 right into the trachea. Something a face mask will never accomplish
2. In CHF positive pressure can counterbalance some of the effects of pulmonary edema
3. In COPD/asthma positive pressure may help stent open the airways

Hope that helps

I'm going to start jotting down numbers before my memory starts failing next time. 😡
It was my first critical care case for documenting, so bare with me. 🙂

I do remember his systolic was 220, then 185.
C02 was into the 100's (don't know if there was a p in front of it, but I think so). There were a bunch of different gasses I had to write down. I know for sure all of them were way out of normal range and the doc used them to make a decision on whether or not to intubate. As he went over it with another doctor, he said he gave him a very small dose of the meds (lasix sounds familiar) and that it shouldn't have dropped so much. The way he was talking sounded like he thought the intubation had played a part in it. We got busy and I wasn't able to ask him how. 🙁

 

[mikecwru]

I'll present the question first since some of you hate paying attention. 😛
Why would intubation lower BP, and also why does intubation work so well for hypoxia? Do accessory muscle use make the lungs less efficient?

Here's the story (and this was over a week ago, so details are fuzzy):

We get this 72 yr old fellar. He's working hard to breathe, using accessory muscles even while on a mask. He had no interest in talking and would occasionally follow people around the room with his eyes. Most of the time he stared straight ahead. The paramedics got him with 02 sats in the 40's and they managed to get him into the 60's. They gave nitro and the patient had asprin before the paramedics arrived...you know typical stuff for chest pain, sob.

I look at the monitor to jot down his BP and holy moly, it's 220/195 (I do all of the documentation for the doctor). And then something goes wrong with the equipment and we can't get a constant measurement on him. I don't remember what his pulse was. I think he was like 104 or so, but don't count on my memory. The doctor hears fluid in the lungs and gives a little of "this" to try and get fluid out of his lungs as well as a little of "that" to lower his BP (I can't remember the drug names. But you guys are smart fellars so I figure you prolly already know).
He had been released from the hosptial only two days prior with a beautiful chest x-ray. We got another in the ED and it's heart failure times eleventy billion.
The doc gives time for the drugs to work. The lungs sound better and his BP dropped to 185/150-something, but he's still circling the drain. We pull blood gasses on him and they're into the 100's. So, the doc intubates.
It goes smoothly and we walk out. We see a patient and while I pull up labs, the doctor goes to back to see the critical one. Soon, I hear him loudly bitching out the staff over not letting him know his BP dropped to 60, and he drops into a chair and tells the entire story to another doctor standing there.

Why would the BP bottom out after intubation? Why would intubating lower the blood gasses when, by the x-ray, the patient was lucky to have any gas exchange in his lungs regardless?

BP drops after intubation for a lot of reasons
1. Induction drug related. vasodilation, anxiolysis
2. Increased intrathoracic pressure, complications related to that autopeep, pneumothorax

Intubation helps for several reasons and some unique ones for heart failure
1. You use pressure to blow open the lungs
2. You can deliver 100% oxygen
3. The pressure effects that can cause you blood pressure to drop mechnically cause the drug effects we try to get in heart failure, it decreases the venous return to the heart and decreases the pressure (afterload) the heart has to pump against
4. When you paralyze, sedate someone, you decrease oxygen consumption. In a very ill person, oxygen consumption just to do the work of breathing can get very high.

mike

 

[BKN]

I'm going to start jotting down numbers before my memory starts failing next time. 😡
It was my first critical care case for documenting, so bare with me. 🙂

I do remember his systolic was 220, then 185.
C02 was into the 100's (don't know if there was a p in front of it, but I think so). There were a bunch of different gasses I had to write down. I know for sure all of them were way out of normal range and the doc used them to make a decision on whether or not to intubate. As he went over it with another doctor, he said he gave him a very small dose of the meds (lasix sounds familiar) and that it shouldn't have dropped so much. The way he was talking sounded like he thought the intubation had played a part in it. We got busy and I wasn't able to ask him how. 🙁

Acute Pulmonary Edema in a patient with an OK heart leads to a sympathetic storm: severe hypertension, tachycardia and sometimes to severe hypercarbia (PCO2>100 = imminent death).

So your Docs intubated him and put him on the blower. Under postive airway pressure the alveoli clear the fluid (see Starling's equation as applied to the pulmonary vasculature). His lungs clear, the emergency is past - the sympathetic drive goes away, his pressure drops to normal. then he's a little overventilated, the intrathoracic pressure is now positive and > than the right atrial pressure decreasing blood return to the heart. BP drops.

So reduce the ventilatory pressures. tidal volumes and rate and things will perk up.

Anyway, that's my 1970's era physiology and critical care explanation.🙄