Ординатура / Офтальмология / Английские материалы / Basic Principles of Ophthalmic Surgery_Arnold_2006

Many doctors routinely drink coffee or teabeforeperforming surgery, yet studiesinvolving hand steadinesssupport the assertionthat caffeine increaseshand tremor. One study noted that after ingestion of 200mg of caffeine,tremor was significantly increasedwhen measuredwith a handheld laserpointer model. Another study, employing a high-resolution, noncontact position tracking system,found that ingestion of 200mg of caffeinecauseda 31% increasein tremor from baseline.Basedon thesedata,caffeineshould be avoidedto minimize tremor during ocularsurgery.

Performanceartists and surgeonshaveemployed ~-adrenergicblock- ing drugs to improve their performance.Severalstudiesassessthe effect of ~-blockers on ocularsurgery,or handtremor. Using the samehigh-resolu- tion, noncontactposition tracking systemasemployed for the caffeinestudy,

subjectswho ingested10mg of propranolol (a nonselective~-blocking agent) were found to have22% lesstremor than atbaseline.No adverseeffectsor sideeffectswere reported. Ophthalmology residentsgiven 40mg of propranolol1 hour before performing ophthalmic microsurgery experienceda significant reduction in tremor andperceivedanxiety.However, there wasno difference in complication ratesor difficulties during surgery.Similarly no negativeeffectsor sideeffectswere encounteredin study participants. A study involving ingestion of timolol12.5 mg aswell asa postural orthotic concluded that neither "accordeda significant benefit in allaying hand tremor." In summary, ~-blocker use,particularly oral propranolol, may diminish hand tremor, but this differencehasnot beenproven to affect surgicaloutcomes.

HAND PREPARATION

Handwashing or scrubbing is a time-honored routine in surgery.Without question, handwashingdecreasesthe surgeon'sskin flora counts, which may in turn lower postoperative infection rates,especiallyin the eventof glove failure. Severalareasof controversy surround the surgicalscrub,however.The duration of handwashinghas beenstudied, with results indicating that a 2-minute period of chlorhexidine useis equivalentto 4- and 6-minute time periods. Improved alcohol solutions for handrubbinghavebecomepopular and are presentin most institutions. A study reported that the useof a 75% aqueous alcoholic solution containingpropanol-I, propanol-2, and mecetroniumetilsulfatecausesno difference in postoperativeinfection ratescomparedwith use of 4% povidone iodine or 4% chlorhexidine gluconate.Additionally, handrubbing with analcohol-basedsolution hasbeenshown to result in a significantly

KEY POINTS

~Preparation of the surgeonincludesdetailed review of the patient'sophthalmologic and generalmedicalstatusalongwith the planned surgical procedure.

~The operating surgeonshould becomefamiliar with the complexequip-

mentto be used in the procedure, including setup,positioning, and

common malfunction remedies.

~Sleepdeprivation, physicalexertion, and caffeineingestion may all have a detrimental effect on a surgeon'sperformance.

SELF-ASSESSMENT TEST

1.In preparation for surgery,the surgeon(list all that apply)

a.Need not necessarilyexaminethe patient personally

b.Must be facile with all stepsof the plannedprocedure

c.Should be familiar with all major equipmentinvolved, including common causesof malfunction and their correction

d.Should review all pertinent ancillary testspersonally

2.List two physicalfactors that may negativelyaffect surgical performance.

3.The caffeinecontained in one cup of coffee mayinduce detrimental hand tremor. (true or false)

4.The controversy in surgicalhand preparationincludes (list all that

apply)

a.Duration of scrub

b.Composition of the antibacterialagent

c.Necessityto scrub

d.Requirementfor gloves

1orpreferred responsesto thesequestions,seepages223-224.