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Letters & E-mails
Do Antibiotics Mask Flashing's Risk?
OSD Staff
Publish Date: August 7, 2008

Do Antibiotics Mask the Risk Of Infection from Flashing?
Re: "What's Wrong With Flashing Cataract Instruments?" (July, page 54). On page 56 of this article, a manager of a Missouri ASC says, "The surgical site infection rates do not support AORN's statement at all." If this ASC's patients don't receive prophylactic antibiotics before cataract surgery, then this nurse's point may be valid. But if patients are routinely treated pre-surgically with prophylactic antibiotics, then this nurse's point — and the argument's linchpin that flashing isn't associated with an increased risk of infection — is potentially misleading. Could it be that flashing is associated with an increased risk of infection, but that these infections are hidden and killed by the antibiotics, thereby masking and preventing the identification of an increased risk of infection associated with flashing ophthalmic (and other types of surgical) instruments?

This question about prophylactic antibiotics and its answer are part and parcel to any discussion about the risk of infection associated with flashing ophthalmic instruments. Nevertheless, it's rarely discussed in articles about this topic. I think not to address this issue is a potential oversight.

Before such conclusions as this Missouri manager's can result in a change in practice favoring routine flashing, controlled studies need to be done and referenced involving flashed ophthalmic instrument sets with one group of cataract patients receiving prophylactic antibiotics while the other does not. I believe such a study is possible and would be deemed medically ethical.

This type of study might reveal a significant difference between the infection rates associated with these two groups, suggesting a possible increased risk associated with flashing. To contend, if not argue, that flashing doesn't pose an increased risk of infection without discussing other relevant factors — such as whether patients were treated pre-surgically with antibiotics — is to miss the point, possibly subordinate patient safety and suggest erroneously that a potentially unsafe practice is without risk.

Lawrence F. Muscarella, PhD
The Q-Net Monthly
[email protected]

Sevoflurane vs. Desflurane
Re: "10 Ways to Save on Supply Costs" (May, page 42). The author suggests that you encourage your anesthesia providers to use sevoflurane instead of desflurane by "showing them the formula for calculating the cost differences in inhalation anesthesia per minimum alveolar concentration (MAC) hour." You must be under the impression that we are unaware of this formula and don't know how to calculate this expense. Additionally, you think (or were informed) that less sevoflurane is used per case when compared to desflurane simply because 1 MAC of sevoflurane is 2.1 percent and 1 MAC of desflurane is 6.0 percent. I'm not sure you understand the use of the minimum alveolar concentration concept as it applies to the patient. Use your formula and run 1 MAC of desflurane at 0.5L/min of fresh gas flow for an abdominoplasty, mastopexy or liposuction case that typically takes four hours. Now run 1 MAC of sevoflurane at the FDA-approved 1 to 2L/min fresh gas flows for 2 MAC hours (don't forget the over pressurization immediately after induction). What must you do after the initial 2 MAC hours? Increase your fresh gas flows to a minimum of 2L/min to avoid potential renal complications.

You'll see that desflurane (with FDA-approved low fresh-gas flows) is actually less expensive than sevoflurane. Desflurane also has the added advantage of earlier eye opening and decreased time to extubation (Nathanson et al. Anest Analg 1995; 81:1186-90) plus faster return of airway reflexes (McKay et al. Anest Analg 2005; 100:697-700). Faster extubation cuts OR time and faster airway reflexes cut PACU time. Sevoflurane has its advantages also, but using it doesn't save money.

Saving money in the anesthesia department should result from a discussion with the anesthesia providers.

David P. Volk, MS, CRNA
President, Bay Anesthesia P.C.
[email protected]

For the Record