Careful monitoring is important in ophthalmic surgery because the patients are usually elderly, covered with drapes, and susceptible to the effects of the oculocardiac reflex. This report presents a cardiac monitor for use in ophthalmic surgery when an anesthesiologist is unavailable. The monitor consists of a precordial chest piece, extension tubing, and an ear piece for the surgeon. The surgeon is able to continually monitor the rate, rhythm, and intensity of his patient's heart beat, and can quickly note decreased cardiac output.
Goldstein JH, Myers DN. A Simple Cardiac Monitor for Ophthalmic Surgery. Arch Ophthalmol. 1971;86(1):97-99. doi:10.1001/archopht.1971.01000010099019