Pain and sympathetic fibres are blocked first, motor fibres blocked later. So sympathetic blockade is very common with epidurals/spinals and peripheral blocks even with low concentration solutions. Once a threshold is reached, however, no further block occurs. I suspect this threshold is the same for sympathetic fibres as for pain fibres. Ie once you have acheived total analgesia with whatever solution you use, you have probably acheived maximal sympathetic blockade.

Hope this is clear enough. Why do you ask?

ECG is harmless, non-invasive, easy and occassionally is the first sign of ischemia or arrhythmia. Riskbenefit ration strongly in favor of using it always!

Plus injecting propofol slowly rather than as a "bomb" makes for a smoother induction with less airway irritibility.

Quote from: jetproppilot on January 19, 2005, 02:07:36 AM
Have had four hematomas in eight years and without an ETT the results could've been catastrophic.

Sure, but hematomas usually happen in the post-operative period by the time the patient has been extubated. What about for intra-operative use?

I should add that no aminoglycosides were used on either patient.

Our department has had 2 reported instances (reported to our Morbidity and Mortality Review Committee) of sensori-neural deafness following general anesthesia. Both patients were otherwise well, having 1-2 hour procedures (peripheral limb surgery for one, and laparotomy for the other) with no hearing loss pre-op. They reported partial deafness both worse in one ear than the other. referal to ENT  - opinion was sensori-neural deafness (not simple conductive) of fairly high grade in one ear in each patient. So far, each has lasted 6 weeks with no signs of resolution.

Has anybody else come across this?

I have a concern with MH.

Nowadays it is really easy to give a non-triggering anesthetic. If I get a patient with known MH, or a relative of an MH patient, or even anybody remotely suspected of MH (perhaps a vague history of getting "hot" during a previous GA), then I give them a propofol infusion. Easy. No need to do cumbersome, invasive muscle biopsy tests.

Well I think there is still the need to test. What we are ending up with is a generation of patients who are suspected of MH but not biopsy-proven MH. Sure we can give them all non-triggering GA's. But what happens next generation? Do we suspect all their relatives to be MH psoitive as well? How far do we suspect? Will the history of suspected MH get reliably transmitted within the family?

I think we are already seeing a group of patients that have such a vague history, because their relative were not tested. It is easy to envisage a relative of a suspected MH patient slipping through the system and not give the history and then get a volatile anesthetic.

We still need to test all suspected MH patients, if not pre-op, then certainly post-op (or ideally as aprt of their current operation).

Datex Entropy module seems to correlate well with the BIS readings. I found this abstract:

QuoteAnesthesiology. 2004 Dec;101(6):1283-90.

 
Comparative evaluation of the Datex-Ohmeda S/5 Entropy Module and the Bispectral Index monitor during propofol-remifentanil anesthesia.

Schmidt GN, Bischoff P, Standl T, Hellstern A, Teuber O, Schulte Esch J.

Department of Anesthesiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany. guschmid@uke.uni-hamburg.de

BACKGROUND: Different analytical concepts were introduced to quantify the changes of the electroencephalogram. The Datex-Ohmeda S/5 Entropy Module (Datex-Ohmeda Division, Instrumentarium Corp., Helsinki, Finland) was the first commercial monitor based on the entropy generating two indices, the state entropy (SE) and the response entropy (RE). The aim of the current study was to compare the accuracy of SE and RE with the Bispectral Index(R) monitor (BIS(R); Aspect Medical Systems, Newton, MA) during propofol-remifentanil anesthesia. METHODS: The authors investigated 20 female patients during minor gynecologic surgery. SE, RE, BIS, mean arterial blood pressure, heart rate, and sedation level were recorded every 20 s during stepwise increase (target-controlled infusion, 0.5 microg/ml) of propofol until the patients lost response. Five minutes after loss of response, remifentanil infusion (0.4 microg . kg(-1) . min(-1)) was started. Spearman correlation coefficient and prediction probability were calculated for sedation levels with SE, RE, BIS, mean arterial blood pressure, and heart rate. The ability of the investigated parameters to distinguish between the anesthesia steps awake versus loss of response, awake versus anesthesia, anesthesia versus first reaction, and anesthesia versus extubation was analyzed with the prediction probability. RESULTS: SE correlates best with sedation levels, but no significant differences of the prediction probability values among SE, RE, and BIS were found. The prediction probability for all investigated steps of anesthesia did not show significant differences among SE, RE, and BIS. SE, RE, and BIS were superior to mean arterial blood pressure and heart rate. CONCLUSION: SE, RE, and BIS revealed similar information about the level of sedation and allowed the authors to distinguish between different steps of anesthesia. Both monitors provided useful additional information for the anesthesiologist.

I am using parecosib routinely for anything but the most minor surgery, and avoiding asthmatics and renal disease patients. I find that it is extremely effective, with markedly decreased narcotic requirements when given early enough.

Two points need to be made:

• It works at the site of injury, so it is useless giving it while a torniquet is in situ. Wait for the torniquet to be released, and then the limb becomes relatively hyperemic and more of the active drug gets to the site of injury. ALternatively, give it well before the torniquet is inflated.
• Be very careful in patients with a history of sulfur allergy. Valdecoxib, the active metabolite of parecoxib has a tricyclic structure and a sulfur element. See this warning (its a pdf file).

I commonly have my CO2 in the 50s and occassionally in the (low) 60's. Rarely higher and then only for short periods (ie I take over and ventilate).

If it looks like aspiration, smells like aspiration, sounds like aspiration, then its got to be.....?






;)

Does anyone (else) use LMAs for endarterectomies?

Works a treat the 3 times of tried it. Got to get the surgeon used to it, as it does give a degree of fullness in the neck.