Supplemental O2 for MAC Cases: Is it Valuable? Is it a Hazard?

Doris M. Penndorf, CRNA

To the Editor

I need advice on addressing what I feel is an unsafe practice in our operating room regarding supplemental oxygen to patients having cataract extraction utilizing M.A.C.

Currently the patient has applied NIBP, EKG, pulse oximeter, and I additionally add a sternal notch stethoscope. A large curved perforated aluminum bar (placed in the traditional ‘ether screen” location) with 8-10 L/M oxygen flowing through it and out near the patient’s head is installed, the patient is sedated minimally, and the retrobulbar block is administered by the surgeon. The patient is then draped with disposable draping material with the long body sheet tented up onto one IV poll to allow visualization of the patient’s lower face and to allow escape of accumulated supplemental oxygen and exhaled carbon dioxide.

My concerns are:

1. Sedating a geriatric patient without nasal oxygen in place

2. Collection of such a large volume of oxygen under the drapes

a. Does not help oxygenation much (minimally raises the SaO2 per pulse oximeter readings)

b. Creates a potential fire hazard

c. May promote rebreathing of the exhaled carbon dioxide which is not being properly vented away from the patient?

3. Potential fire hazard

a. Cautery is used (battery operated, but still hot enough to bum the drape material)

b. Disposable draping material is used

c. High flow oxygen is accumulating under the drapes

Fires in the OR are reported and the dangers are worse with the unregulated flammability of disposable drapes. I even saw a lengthy article on the subject in a professional firefighting journal.

I would appreciate any information to provide a safer anesthesia experience for our patients.

Doris M. Penndorf, CRNA Winsted, CT

Editor’s Note: Readers are invited to respond and replies will be considered for publication in this column.