Practical aspects of working in the operating room

Intraoperative neurophysiologic

monitoring• Electrophysiologic recordings in an

electrical hostile environment• Electrophysiologic recordings in an

anesthetized patients• The need to obtain interpretable records

in a short time• Interpretation of results must occur

promptly • What changes to report and what not to

report?• Communication with the surgeon• Relation with the anesthesia team• Relations with other members of the

operating room team

Electrophysiologic recordings in an

electrical hostile environment • Survey an operating room that you

not familiar with for sources of electrical interference– Best done the evening before an operation

• Always be in the operating room early enough to solve unexpected problems

• Always monitor the recorded potentials directly during an operation– EEG tells the signature of interference; averaged potentials do not

Find the source of interference

Electrophysiologic recordings in an

anesthetized patient• Advantages:

– Can use needle electrodes freely– Can stimulate peripheral nerves supramaximal

• Disadvantages:– Can cause injury by too strong electrical stimulation of nerves or CNS

The need to obtain interpretable records in

a short time• Use optimal stimulus and recording parameters

• Reduce noise as much as possible at its source

• Use optimal placement of electrode wirings

• Plan your recordings ahead to avoid waste of time

Interpretation of results must occur

promptly• Prepare yourself ahead of time so you understand the recordings and their interpretation

• Understand the different kinds of changes that can occur and their meaning with regard to pathologies

What to report to the surgeon?

INFORMATION THAT IS OF VALUE

• Changes in recorded potentials

• All unusual events• In case of dramatic changes:

– First assume a biologic cause and always notify surgeon immediately

– Then check equipment etc.

What changes to report?

• Changes in the recorded potentials that are larger than the normal (small) variations

What not to report?

• Data without interpretationA stream of numbers

without interpretation is of little value

Communication with the surgeon

• The surgeon is not a physiologist• Therefore: Provide interpreted results, not raw data

• Place the observed changes in relationship to the ongoing operation

• You must know the basic steps in the operation you are monitoring

Interpretation of pathologic changes

• Which parameters are important?

• What to use as reference values?

• What is significant?

Change in relation to what?

• How to get a representative baseline

Which parameters are important?

• Latency• Amplitude

Non-pathologic changes

• Change in anesthesia• Change in body temperature

Artifacts

• Stimulus artifacts• Movement artifacts• Irrigation with cold saline may cause changes in recorded potentials

False positivesFalse negatives

• Limited relevance for intraoperative monitoring

Relation with the anesthesia team

• Always discuss a case with the anesthesia team before an operation– What kind of anesthesia they want to use

– How that will influence your workFor that you must know the basics of modern anesthesia techniques

Relation with the anesthesia team

• Interchange of information– You can provide information of value for the anesthesia team

– They can let you know of changes in vital signs and in anesthesia regimen

Relation with the anesthesia team

• Discuss each operation with the anesthesiologists in advance

• Ask to be informed about any changes in the anesthesia regimen that may occur during an operation

• Watch their displays and understand what they mean

• Treat the anesthesiologists as your friends and try to understand their situation and problems

Relations with other members of the operating

room team• Keep a good relationship with all nurses in the operating room (they control the environment)

• Do not be afraid of offering a helping hand

• Remember that they (and you) are all there for one single purpose, namely to provide the best possible care for the patient

Practical aspects of working in the operating room

• Should the person who is responsible for monitoring be present in the operating room? YES

• Can monitoring be done by watching a display of recorded potentials in an another room? NO