Medical Pharmacology Chapter 12:  Anxiolytics and Sedative-Hypnotics

Preoperative Medication: Sedative Hypnotics and Other Agents and Issues

• ⁴Steroids

  • Overview: patients who may need need steroid administration  immediately before surgery

    1. Patients being treated for hypoadrenocorticism

    2. Patients who have pituitary-adrenal axis suppression due to ongoing or previous steroid treatment -- generally more suppression would be anticipated if the treatment had been for longer duration and at higher dosages

    3. General rule: Consider preoperative treatment give the patient has been on steroids for one month in the last six months preceding surgery.

  •  The major clinical perioperative consequences of  pituitary-adrenal axis suppression is the inability of the patient to respond properly to surgical stress. 

    • Accordingly, supplemental steroid protocols could include:

      • Method #1:  Appropriate dose of  cortisol preoperatively followed by IV infusion of a likely higher cortisol dose during the next 12-24 hours (adult patients)

      • Method #2: Administration of  an appropriate dose of hydrocortisone (Cortef, Solu-Cortef) intravenously before, during and then after the procedure.  This approach is an effort to estimate a maximal amount of steroids that would be released in response to surgical stress. 

        • Generally, the risk-benefit ratio for steroid administration and dosage is small.

• Antibiotics:

  • Antibiotics are considered for administration immediately before surgery for "contaminated, potentially contaminated, or dirty surgical wounds."

  • Prophylactic antibiotics may be used for certain patients groups including:

    • Elderly patients

    • Immunosuppressed patients

    • Patients taking steroids

    • Patients who are at risk for development of endocarditis, including patients with valvular heart disease, patients who have mitral valve prolapse, and patients who have prosthetic valves.

  • The reason that the anesthesia provider is involved in antibiotic administration is that the antibiotics will be administered immediately preceding the surgical procedure-just before potential contamination could occur.

  • Approximately 60%-70% of patients receive antibiotics intraoperatively or just prior to the beginning of the procedure.

  • The antibiotics class most commonly used is the cephalosporins.

  •   Side effects and complications may occur with antibiotic administration.  The side effects may include:

    1. Allergic reactions

    2. Hypotension

    3. Bronchospasm (examples here might be penicillin or vancomycin (Vancocin))

  • Side effect frequency: Approximately 5% of patients have some "allergic" reaction to cephalosporin. 

    • Furthermore, the cross-reactivity between cephalosporins and penicillins is estimated to be about 5%-20%

  • Some antibiotics are noted for their tendency because nephrotoxicity (renal toxicity).  

    • These antibiotics include the aminoglycosides, vancomycin (Vancocin) and polymixins.

  • Ototoxicity is associated both with vancomycin (Vancocin) and aminoglycoside administration.

  • A specific side reaction of clindamycin (Cleocin) use is pseudomembranous colitis.  

  • Aminoglycosides enhanced neuromuscular-blocking properties of muscle relaxants.

• Insulin:

  • Overview: Because of interruption of normal eating schedules and the stress associated with surgery, specific plans are required to manage the insulin-dependent patient.  

    • Collaboration between the anesthesia provider surgeon and endocrinologist is the basis for determining how insulin will be provided.

  • Several approaches (methods) are available.

    1. One approach is the administration of 1/4 to one-half of the usual daily intermediate-acting insulin dose preoperatively in the morning of surgery followed by a glucose-containing fluid infusion.

    2. A second approach is the administration of no insulin or no glucose preoperatively accompanied by intraoperative  blood glucose monitoring, allowing regular insulin or glucose administration intraoperatively and postoperatively as required

    3. A third approach is based on initiation of insulin and glucose infusion immediately preoperatively along with frequent serum glucose level determinations.

References

• ¹Preoperative Medication in Basis of Anesthesia, 4th Edition, Stoelting, R.K. and Miller, R., p 119- 130, 2000) 

• Hobbs, W.R, Rall, T.W., and Verdoorn, T.A., Hypnotics and Sedatives; Ethanol In, Goodman and Gillman's The Pharmacologial Basis of Therapeutics, pp. 364-367 (Hardman, J.G, Limbird, L.E, Molinoff, P.B., Ruddon, R.W, and Gilman, A.G.,eds) TheMcGraw-Hill Companies, Inc., 1996.

• ³Sno E. White The Preoperative Visit and Premedication in Clinical Anesthesia Practice pp.  576-583 (Robert Kirby and Nikolaus Gravenstein, eds) W.B.  Saunders Co., Philadelphia, 1994

• ⁴John R. Moyers and Carla M. Vincent Preoperative Medication in Clinical Anethesia, 4th edition, 551-565, (Paul G. Barash, Bruce. F. Cullen, Robert K. Stoelting, eds) Lippincott Williams and Wilkins, Philadelphia, PA, 2001

• ⁵Gertler, R., Brown, H. C, Mitchell, D.H and Silvius, E.N Dexmedetomidine (Precedex): a novel sedative-analgesic agent, BUMC Proceedings 2001; 14:13-21 .