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Like woodenpug said, "it depends". that's such a great answer.
look at the cause of the tachypnea. in this case it's CHF, but what if it was an acid-base derangement instead? then slowing down the rate would not be appropriate. we had a lady whose resp rate was 4-5...someone suggested we bag her but her pH was 7.6, her body was attempting to compensate for metabolic alkalosis and increasing her respiratory rate would have been inappropriate (her vitals were stable and saturations in the 90s).
in your case, did you give anything besides oxygen and mso4? the morphine works in conjunction with diuresis as it dilates the vessels allowing them to accomodate more fluid. so the pulmonary edema passes through the alveolar membrane and is subsequently diuresed as it passes through the kidneys. albuterol and lasix are other medications that works in tandem with o2 and mso4. and there are plenty of additional meds that we consider when someone has an acute CHF episode.
you're right about the anxiolytic effect of morphine, but there's a vascular effect that comes into play as well.
you seem to have good skills in processing disease, pharmacology and clinical pictures. keep up the good work!
Morphine is used primarily for its effect on preload and afterload reduction. It is also anxiolytic and analgesic. This is why it's so effective in Myocardial Infarction. As veins dilate, the amount of blood returning to the heart drops, so there is less fluid volume to "congest" or back up into the lungs from the failing heart. Pain is relieved, the pt is less anxious, lowering metabolism and thus overall O2 requirements. As blood pressure drops, so too does systemic vascular resistance (or afterload), allowing the heart to pump more effectively because there is now less resistance opposing it.
Tachypnea of anxiety can be treated by rebreathing from a paper bag, or if that fails, then sedation with something like a mild benzodiazepine may be more appropriate. But, morphine is never used to treat the tachypnea of CHF. If someone is oxygen starved like a classic CHF presentation, giving morphine to decrease respiratory drive would be tantamount to cutting off his oxygen completely. That is, the fast breathing pattern isn't a reflection of CO2 retention (a problem of COPD); it is the lack of oxygen or hypoxia that is driving the tachypnea of CHF. Morphine's essential effect here is on the cardiovascular system and hence, by decreasing myocardial workload, it then lowers O2 demand. This is what will then slow the breathing.
Again, it is not because of the opiate depressive effect on the respiratory center of the brain. Giving enough morphine to slow breathing is, in effect, likened to giving someone a heroin overdose.
I'm trying to wrap my head around pharmacologically reducing the patient's RR when it is his body trying to compensate for lack of oxygen. Is this action always appropriate for tachypnea? Thank you in advance for sharing your experiences!
simply put, morphine reduces the need for o2.
it also assists with the oft concurrent anxiety levels.
diuretics, nitrates, beta blockers, ace inhibitors...whatever is appropriate for the pt...are typically the meds that will stabilize chf symptoms.
morphine, is still a minor component of the tx regimen.
because of its near-immediate effects, it indeed, palliates the pt in distress.
as to the bolded (emphasis, mine), no..not always appropriate.
as with any treatment, it needs to be based on pt presentation.
keep in mind, morphine is only used til the other meds take effect...
so the chance of overdosing and/or resp depression, are extremely rare.
hoping this makes sense to you...someone...anyone??
leslie
Menji
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I'm a student nurse. In clinical recently, a patient developed tachypnea. This was thought to be due to CHF. Oxygen was given, and morphine was administered for its respiratory depressive effects. I understand that we gave the morphine to prevent the patient from exhausting himself and to ease his work of breathing. I'm trying to wrap my head around pharmacologically reducing the patient's RR when it is his body trying to compensate for lack of oxygen. Is this action always appropriate for tachypnea? Thank you in advance for sharing your experiences!