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| No. 10 | 
Sep 25, 2005, 12:38 PM
 Hyperventilation Originally Posted by hrtprncss HI quick question, I know that sedation then let's say norcuron then barb coma, with concommitant use of mannitol and other things are being implemented. I just want to know how many people still use hyperventilation as a technique to decrease ICP, i know it's been basically supposedly phased out...But is anyone still hyperventilating a patient, post 24 hours, to well i don't mean to control ICP but used as a short term adjunct to temporary decrease it in emergent situations...Curious to know...hrtprncss
There is alot of literature (especially pediatric) which shows detrimental effects of prolonged hyperventilation (terrible ischemia). Short term (usually less then 6-8 hours) not too terrible but DO NOT abruptly stop, you have to slowly increase the CO2, an abrupt increase (as you know) is bad news.
Mike
 | | Advertisement Sponsored Links | | | | No. 11 |
Sep 25, 2005, 12:40 PM
Some info Originally Posted by mwbeah There is alot of literature (especially pediatric) which shows detrimental effects of prolonged hyperventilation (terrible ischemia). Short term (usually less then 6-8 hours) not too terrible but DO NOT abruptly stop, you have to slowly increase the CO2, an abrupt increase (as you know) is bad news.
Mike
Here is an abstract:
J Neurosurg. 1991 Nov;75(5):731-9. Related Articles, Links Adverse effects of prolonged hyperventilation in patients with severe head injury: a randomized clinical trial. Muizelaar JP, Marmarou A, Ward JD, Kontos HA, Choi SC, Becker DP, Gruemer H, Young HF.
Division of Neurological Surgery, Medical College of Virginia, Richmond.
There is still controversy over whether or not patients should be hyperventilated after traumatic brain injury, and a randomized trial has never been conducted. The theoretical advantages of hyperventilation are cerebral vasoconstriction for intracranial pressure (ICP) control and reversal of brain and cerebrospinal fluid (CSF) acidosis. Possible disadvantages include cerebral vasoconstriction to such an extent that cerebral ischemia ensues, and only a short-lived effect on CSF pH with a loss of HCO3-buffer from CSF. The latter disadvantage might be overcome by the addition of the buffer tromethamine (THAM), which has shown some promise in experimental and clinical use. Accordingly, a trial was performed with patients randomly assigned to receive normal ventilation (PaCO2 35 +/- 2 mm Hg (mean +/- standard deviation): control group), hyperventilation (PaCO2 25 +/- 2 mm Hg: HV group), or hyperventilation plus THAM (PaCO2 25 +/- 2 mm Hg: HV + THAM group). Stratification into subgroups of patients with motor scores of 1-3 and 4-5 took place. Outcome was assessed according to the Glasgow Outcome Scale at 3, 6, and 12 months. There were 41 patients in the control group, 36 in the HV group, and 36 in the HV + THAM group. The mean Glasgow Coma Scale score for each group was 5.7 +/- 1.7, 5.6 +/- 1.7, and 5.9 +/- 1.7, respectively; this score and other indicators of severity of injury were not significantly different. A 100% follow-up review was obtained. At 3 and 6 months after injury the number of patients with a favorable outcome (good or moderately disabled) was significantly (p less than 0.05) lower in the hyperventilated patients than in the control and HV + THAM groups. This occurred only in patients with a motor score of 4-5. At 12 months posttrauma this difference was not significant (p = 0.13). Biochemical data indicated that hyperventilation could not sustain alkalinization in the CSF, although THAM could. Accordingly, cerebral blood flow (CBF) was lower in the HV + THAM group than in the control and HV groups, but neither CBF nor arteriovenous difference of oxygen data indicated the occurrence of cerebral ischemia in any of the three groups. Although mean ICP could be kept well below 25 mm Hg in all three groups, the course of ICP was most stable in the HV + THAM group. It is concluded that prophylactic hyperventilation is deleterious in head-injured patients with motor scores of 4-5.(ABSTRACT TRUNCATED AT 400 WORDS)
| | No. 12 |
Sep 25, 2005, 12:43 PM
Info
Caveat,
When reading articles (whole 'nother topic) and taking information from people, I would hope that everyone is like I am:
"Let me do some research on my own and see if what they said is true..."
Never take anything at face value, you will become a better practitioner if you "verify" that what your doing is the standard.  Mike
| | No. 13 |
Sep 25, 2005, 12:52 PM
Thank you, another HYPOTHETICAL situation....let's say you're in CT or for arguments sake let's just say MRI a place where the ICP has been elevated may it be from moving the patient and irritating the patient for some reason. Then your patient exhibits signs of herniations(this might be an extreme example) and the ICP shoots up and it won't come down. When medications are not readily available at hand, and you decide to manually bag the patient to decrease the ICP. Then do you recommend that when the patient goes back to the unit, to place that patient on a higher rate on the ventilator? as oppose to the original RR before you went down? Please keep in mind this is hypothetical and sometimes and not always, things are not within reach such as medications...
| | No. 14 |
Sep 25, 2005, 01:07 PM
Yeah Originally Posted by hrtprncss Thank you, another HYPOTHETICAL situation....let's say you're in CT or for arguments sake let's just say MRI a place where the ICP has been elevated may it be from moving the patient and irritating the patient for some reason. Then your patient exhibits signs of herniations(this might be an extreme example) and the ICP shoots up and it won't come down. When medications are not readily available at hand, and you decide to manually bag the patient to decrease the ICP. Then do you recommend that when the patient goes back to the unit, to place that patient on a higher rate on the ventilator? as oppose to the original RR before you went down? Please keep in mind this is hypothetical and sometimes and not always, things are not within reach such as medications...
Short term, hyperventilation has its place. I certainly would use it if I had nothing else (in the short term). But, I wouldn't take the CO2 too low (maybe 20-25).
Mike
| | No. 15 |
Sep 25, 2005, 01:22 PM
Thank you, thanks for the info and in regards to taking it face value, i was basically curious to know if there was deviations as to what the literature says compared to what's done in real settings as handled by other neuro RN's.
| | No. 16 |
Sep 25, 2005, 05:39 PM
Originally Posted by mwbeah Are you implying...........?
Lets see, I work with propofol daily. When the BP drops, I believe that you turn the infusion down.....correct me if I am wrong..........
I am a Doctoral Neuroscience student.........I should know the formula..... (JK)
(One question, how can Right atrial pressure affect ICP?)
The CPP number which has been evidenced based is 70mmHg or above with injury:
Chan K H, Miller J D, Dearden N M, Andrews P J D & Midgley S. "The effects of changes in cerebral perfusion pressure upon middle cerebral artery blood flow velocity and jugular bulb venous oxygen saturation after severe brain trauma." J.Neurosurgery 1992; 77: 55- 61.
I wasn't implying anything and my post certainly wasn't directed towards you. Just trying to add my perspective as an experienced neurosurgery nurse and educate those that are new or unfamiliar with that particular scenario.
Additionally, the propofol drip can be turned down, but if you're titrating to sedation and the sedative effects are not therapeutic when the MAP rises sufficiently to support ideal CPP, then it may be necessary to try an alternative drug for sedation.
Good luck with your Doctorate.
| | No. 17 |
Sep 25, 2005, 06:26 PM
Thank-you everyone and we do have to remember that not everyone is posting from America or even a first world country. There are times when we will get questions from people who do not have access to "the latest and the best" but who are interested in what is being done elsewhere.
| | No. 18 |
Mar 27, 2008, 08:40 PM
Re: Propofol
Um, I am not a doctoral neuroscience student but if you had elevated Right atrial pressure--thus leading to JVD and back up of blood would it be implausible to assume a possibility of increased ICP?
Thoughts? Originally Posted by mwbeah  Are you implying...........?
Lets see, I work with propofol daily. When the BP drops, I believe that you turn the infusion down.....correct me if I am wrong..........
I am a Doctoral Neuroscience student.........I should know the formula..... (JK)
(One question, how can Right atrial pressure affect ICP?)
The CPP number which has been evidenced based is 70mmHg or above with injury:
Chan K H, Miller J D, Dearden N M, Andrews P J D & Midgley S. "The effects of changes in cerebral perfusion pressure upon middle cerebral artery blood flow velocity and jugular bulb venous oxygen saturation after severe brain trauma." J.Neurosurgery 1992; 77: 55- 61. |
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