I am a new nurse working in a 32 bed ICU. I was wondering if any of the expereinced nurse know of an easy way to titrate drips. I feel that I am more conservative when it comes to this. Especially when your weaning someone off the vent. It seems like it is more of a judgement call and depends on the pt and where they are hemodynamically?
Also does anyone know of a good hemodynamics book that I could get? Just when I think I get the hang of it I am not so sure I do. I know alot of this comes with experience, just having the patience for that is frustrating at times.
Ok guys I just got in. Have read the forum today. I will tyr to do a "little " lecture on hemodynamics. Let me just say that I am not computer savvy so I'll try ok.
In order to learn and understand hemodynamics, we have to divide the heart into two halves, the RIGHT and the LEFT side to make it easier to understand. Just like we learn about arrhythmias, we divide the heart into two the ATRIUM and the VENTRICLE, hence we classify dysrhytmias into atrail and ventricular. So, keep this in mind.
Another concept to learn is cardiac output. When the critical care team mentions hemodynamics numbers one thing comes into our mind.... CARDIAC OUTPUT. CO is defined as the volume of blood ejected from the left ventricle per minute. CO is expressed mathematically as stroke volum (SV) X Heart rate (HR). And SV is influenced by 3 factors namely: PRELOAD ,AFTERLOAD , and CONTRACTILITY . Normal CO is 4-8L/min.
Now here is the fun part. Remember I mentioned about the RIGHT and the LEFT side of the heart? We will now apply that here.
PRELOAD -- we have heard about the Starling"s Law. To make it easier, I termed preload as VOLUME. Forget about the Starling Law, it is kinda confusing sometimes, just think of Prelaod as Volume. So, when someone says "Preloaders" you know they are talking about volume.
RIGHT SIDE OF THE HEART
the preload at the right side of the heart is the Central Venous Pressure CVP. Normal range bet 4-6mmHG. below the normal range its hypovolemia, about the high range is hypervolemia.
Treatement modalities for hypovolemia are 3 common "preloaders". See I am using the word Preloaders now.
1. Crystalloids eg. LR, NS
2. Colloids eg. hespan, dextran, plasma expanders
3. Blood and blood products eg. FFP, Cryo, RBC
Treatement for hypervolemia
1. Diuretics
LEFT SIDE OF THE HEART
preload at the left side of th heart is Pulmonary Capillary Wedge Pressure (PCWP). Normal range between 8-12mmHG. Other temred used by some physicians to denote wedge pressure are:
a. Pulmonary Artery Occlusive Pressure (PAOP)
b. Left Ventricular End-Diastolic Pressure ( LVEDP)
NOTE: LVEDP is recorded during ECHO. It is advisable to know this number since this is the patients baseline. Once you reach the patients baseline eg if LVEDP is 12. If your Wedge reading is already 12 then you know that giving fluids (preloaders) is not going to help instead it is going to overload the patient.
Treatement modalities for low wedge:
1. Preloaders ---- Fluids fluids and more fuids. If you work in an Open heart unit.... Prelaod is the first and main problemm you are going to encounter. Hence, give them as many as the patient can tolerate because once your Prelaod problem is correctly, it is smooth sailing from there on.
Treatment for high wedge:
1. Diuretics.
So overview for PRELOAD.
RIGHT side = CVP
LEFT side = PCWP
Remember, preload is "volume".
We still have two more... afterload and contractility. We'll do that later. Any question feel free to ask and if any of you fellow nurses have something to add, please do so.
Ok, we have discussed PRELOAD which is one of the DETERMINANTS OF STROKE VOLUME that eventually will affect cardiac output. To all clinicians, evaluating cardiac output is clinically relevant as it effects the heart's ability to meet the metabolic demands of the body's organs and tissues.
Before I go further, I just want to emphasize that measuring CO is not only done invasively ( eg. Swan Ganz ) but it can also be assessed non-invasively. We must remember that not all ICU patients have PA catheter in place. Common non-invasive assessments inlcude:
1. strenght of peripheral pulses
2. MAP. the say it plainly MAP is systolic minus diastolic divided by
3 plus the diastolic. MAP range is 60-80 mmHG.(FYI: We all know that diastolic is more important that systolic when we talked about coronary perfusion. Unlike all the other organs and tissues in our body, the heart obtains perfusion during diastolie not during systole. It is when the heart relaxes that the heart itself gets its nutrients, oxygenated blood. Thus, when patient are in cardiogenic shock Intra-Aortic Ballon Pump is used to increase coronary perfusion by inflating during diastole.)
3. Skin color and temperature
4. LOC
5. Urine output.
Now, let us go to the second factor affecting Stroke Volume. AFTERLOAD.
AFTERLOAD
It is defined as the "Resistance" to ejection of the end-diastolic volume and the amount of ventricular wall tension. In order words, i refer to AFTERLOAD as RESISTANCE. The more constricted the vessels, the more the heart will exert effort to pump blood. Afterload is not directly measured, it is a calculated value or a derived parameter obtained when a PA catheter is in place.
RIGHT SIDE OF THE HEART
The AFTERLOAD at the Right side of the Heart is Pulmonary Vascular Resistance (PVR). Normal range is 50-250.
Treatement for Low PVR:
1. Most of the time nothing at all.
Treatement for elevated PVR:
1. Mostly referred to as Pulmonary Hypertension. We use one common vasodialator. Nitroglycerine.
2. Sometimes Lasix. More than likely, patient with Pulmonary Hypertension tend to have PE, hence a diuretics.
3. Sometimes, MS is used. If your patient is on a vent, this drug is safe to use.
LEFT SIDE OF THE HEART
The AFTERLOAD at the Left side of the Heart is Systemic Vascular Resistance (SVR). Normal Range is 800-1200.
Treatement for low SVR.
1. If patient is not septic, vasopressors are being used. However, remember you have to make sure that your Preload problem is resolved or else when vasopressors are administered prior to resolution of Preload problem, you are going to end with additional problem. If your patient is dry, adding a vasopressor agent can cause tachycardia. And tachycardia is bad for coronary perfusion. During tachycardia, there is little time for the heart to repolarize ( rest) and isn't it that the heart gets perfused during the resting phase? Diastole? So take care of the preload problem before inititating a vasopressor.
Common Vasopressors:
a. Dopamine. Star higher than the renal dose to avail of the vasoconstrictive effects of the drug.
b. Levophed. I love this drug. Levophed leave them dead. No limit on Levophed. You can go as high as you can. The only problem is the bad side effects which is peripheral vasoconstriction.
c. Epinephrine. I hate to say this but this drug is coined as the "Drug of the Dead." I rarely use this unless necessary.
d. Sodium Bicarbonate. I added this here because most of the time when all the above vasopressors are used and still very low SVR ( hypotensive ), patients are more than likely acidotic. And most drugs do not work on a acidic medium.
2. if the patient is septic. Very LOW SVR is the initial phase of the hyperdynamic state of shock. Aggresive use of Preloaders and Vasopressor are utilized.
Specializes in ICU, Agency, Travel, Pediatric Home Care, LTAC, Su.
You had mentioned EDV. Just wanted to comment that Baxter makes continuous cardiac output swans that give you the EDV reading, haven't worked with them in a while, but they are sweet!
Very nice review! I can't wait for tips/pearls on drug titration.
I am just curious, why do you think cardiologists ask for SBP, rather than DBP when in fact DBP is perfect to check cardiac perfusion? What's the DBP parameter to say that coronary perfusion is fine. Can you give us some tips on giving fluids to increase preload? When to choose colloids over cystalloids? When do we say patient we have already given enough fluids - do we wait until we hear crackles? There are still a lot of questions in my mind ....being new taking care of hearts. We choose NEo over Levo in my unit - don't know why.
Most MD's still wants to know more about systolic pressure than daistolic because it tells them target organ perfusion. I am not sure in your practice but have you noticed most of the docs still want to know whethere the systolic is between 120 to 160? Most still do however, when you tell them it is below 80mmHg they tend to worry. Why is that?
First, that is not adequate perfusion for any target organs.
Second, you can bet that the diastolic is way below 50mmHG which is not good for coronary perfusion.
On question about daistolic pressure limit. I would follow the rule of => 60 to 80mmHG as a good rule of thumb for diastolic.
On fluids:
It is safe to start with crystalloids first before colloids. These are easier removed by giving Lasix just in case you overload the patient. You facility/unit should have a protocol on giving fluids. In my unit, we have and we used LR and NS first followed by Hespans. Then of course blood is the best. Obtain H/H to determine if blood is needed.
How to know if fluids are enough, do we wait till patients have crackles?
I make it a habit to read the ECHO result of the patients undergoing CABG or any cardiac surgeries for that matter. In that result you will obtain pertinent baseline informations of the patient. Your LVEDP which is similar to wedge pressure, your EF and your left ventricular function. Most, if not all CABG comes out with a PA catheter. Monitor CVP and Wedge ( although I do not recommend doing wedge pressure every hour, look at your PA diastolic this is a resemblance of your wedge trends ), if these numbers are way up than your pre-op numbers then you are more likely going into pulmonary edema or getting "Wet."
Neo vs. Levo:
Some clinicians do Neo than Levo. It is their preferences. I rarely your Neo.
Specializes in Step down, ICU, ER, PACU, Amb. Surg.
XIGRIS,
Thank you soooooooooo much. You have been more than a help. Some of the things our surgeon has asked for in the recent past are making more sense to me now than they already did. Absitively brilliant!!!! I am forever indebted to you for your little 2 part mini-in service!!!
Specializes in CCU (Coronary Care); Clinical Research.
Regarding drips, it is interesting to read what other hospitals are doing. Our first line is dopamine (we have a whole list of orders for fluid replacement also). If hr increases to >100 we are then to go to epi...we hardly ever use levophed or neo...i see neo a little more than levophed but neither are used much after our hearts. As for fluids...some of our docs prefer hespan and some prefer albumin...we have some standing parameters for these...if no uo and pawp > (usually) 18 or so (depending on the doc) we can give lasix...
Xigris, Just got back online after the weekend, thanks a lot for sharing your knowledge with all of us. Personally I'm printing and saving, as I know I'll forget it over the holidays....and I have learned if I read and reread something, after about the 5th read, I have learned it !
Thanks again for your time. It makes a real difference, reading it and having it explained by someone who knows and understands it.
It seems like it is more of a judgement call and depends on the pt and where they are hemodynamically? 
XIGRIS
234 Posts
Ok guys I just got in. Have read the forum today. I will tyr to do a "little " lecture on hemodynamics. Let me just say that I am not computer savvy so I'll try ok.
In order to learn and understand hemodynamics, we have to divide the heart into two halves, the RIGHT and the LEFT side to make it easier to understand. Just like we learn about arrhythmias, we divide the heart into two the ATRIUM and the VENTRICLE, hence we classify dysrhytmias into atrail and ventricular. So, keep this in mind.
Another concept to learn is cardiac output. When the critical care team mentions hemodynamics numbers one thing comes into our mind.... CARDIAC OUTPUT. CO is defined as the volume of blood ejected from the left ventricle per minute. CO is expressed mathematically as stroke volum (SV) X Heart rate (HR). And SV is influenced by 3 factors namely: PRELOAD ,AFTERLOAD , and CONTRACTILITY . Normal CO is 4-8L/min.
Now here is the fun part. Remember I mentioned about the RIGHT and the LEFT side of the heart? We will now apply that here.
PRELOAD -- we have heard about the Starling"s Law. To make it easier, I termed preload as VOLUME. Forget about the Starling Law, it is kinda confusing sometimes, just think of Prelaod as Volume. So, when someone says "Preloaders" you know they are talking about volume.
RIGHT SIDE OF THE HEART
the preload at the right side of the heart is the Central Venous Pressure CVP. Normal range bet 4-6mmHG. below the normal range its hypovolemia, about the high range is hypervolemia.
Treatement modalities for hypovolemia are 3 common "preloaders". See I am using the word Preloaders now.
1. Crystalloids eg. LR, NS
2. Colloids eg. hespan, dextran, plasma expanders
3. Blood and blood products eg. FFP, Cryo, RBC
Treatement for hypervolemia
1. Diuretics
LEFT SIDE OF THE HEART
preload at the left side of th heart is Pulmonary Capillary Wedge Pressure (PCWP). Normal range between 8-12mmHG. Other temred used by some physicians to denote wedge pressure are:
a. Pulmonary Artery Occlusive Pressure (PAOP)
b. Left Ventricular End-Diastolic Pressure ( LVEDP)
NOTE: LVEDP is recorded during ECHO. It is advisable to know this number since this is the patients baseline. Once you reach the patients baseline eg if LVEDP is 12. If your Wedge reading is already 12 then you know that giving fluids (preloaders) is not going to help instead it is going to overload the patient.
Treatement modalities for low wedge:
1. Preloaders ---- Fluids fluids and more fuids. If you work in an Open heart unit.... Prelaod is the first and main problemm you are going to encounter. Hence, give them as many as the patient can tolerate because once your Prelaod problem is correctly, it is smooth sailing from there on.
Treatment for high wedge:
1. Diuretics.
So overview for PRELOAD.
RIGHT side = CVP
LEFT side = PCWP
Remember, preload is "volume".
We still have two more... afterload and contractility. We'll do that later. Any question feel free to ask and if any of you fellow nurses have something to add, please do so.