About Intraoperative Monitoring

In the past, patients were monitored during their surgeries primarily with a blood pressure cuff, electrocardiogram (ECG) and a stethoscope. Since the 1960s an array of techniques have arisen to allow the anesthesiologist to more carefully monitor your condition while you are "asleep". These include tools to measure your blood oxygen and carbon dioxide content, temperature and, in selected cases, pressures within your arteries and lungs. This has coincided with a dramatic improvement in the rate of anesthesia related death, at least in part due to the better monitoring.

Since 1986, the American Society of Anesthesiologists (ASA) has adopted standards for the use of these the new monitoring tools.

The Challenge

While standard intraoperative monitoring gives your surgeon and anesthesiologist a good picture of the status of your heart and lungs during your surgery, it is more difficult for them to tell if there is anything going wrong with your nervous system. For surgeries that place these organs at risk, such as those to decompress the spinal cord or remove abnormal brain tissue, specialized monitoring is often useful to help avoid or minimize injury during surgery. These tools are now available to your surgeon in the form of neurophysiologic monitoring.

Neurophysiologic Monitoring

Neurophysiologic monitoring is an assortment of monitoring tools or techniques that may be used by your surgeon in different combinations to obtain a picture of the function of your nervous system at various points during your surgery. They usually record brain waves produced in response to several types of stimulation including small electrical pulses applied to peripheral nerves, flashes of light to the eyes and clicks of sound to the ears. Muscles are also monitored for abnormal electrical activity that might suggest injury to the nerve supplying them. There are no lasting side effects from this stimulation. It does, however, allow your surgeon to assess the integrity of the part of the nervous system that he or she is working on or near to. This, in turn, allows for a quick response to evidence of injury or dysfunction,

More complex surgeries to insert stimulation devices in the brain monitor local brain cell activity to guide placement of the stimulator wire.

Richard A. O'Brien MD FRCP(C) MBA

Vice President - Quality Assurance/Medical Director

This data is provided for informational purposes only. It does not substitute for individualized advice from a qualified physician. Although attempts have been made to ensure the material is accurate and up to date it is provided in an 'as is' state. Neither the author nor Impulse Monitoring Inc. assumes any liability for errors or omissions or any problems that might arise due to them. Always consult your physician or qualified health professional before acting on information that concerns your health.