Blog Post 1 - AA

Anagha Arvind
Sep 15, 2019
4 min read

Author: Anagha Arvind

Date: September 15, 2019

Project: Anesthesia Delivery and Monitoring

Team Members: Adin Field, Gordon Ellis, Jordon Bibian, Anagha Arvind

Blog Contents:

1. Background Research

a. What is anesthesia? How does it work? (Ongoing research...)

b. Intra-operative and Intra-anesthetic awareness (Ongoing research...)

c. Standards for Basic Anesthetic Monitoring

2. Needs Statements with Scoping (ongoing...)*

3. Initial list of stakeholders*

4. References

*from lectures about Design Approach, Needs Statements, Stakeholders

Background (ongoing research...)

What is anesthesia? (4) How does it work? (Ongoing research...)

- Anesthetics are used during surgeries to reduce and prevent post-operative pain. There are different types of anesthesia (eg. local, regional, general), but we will be focusing mainly on the effects of general anesthesia.

- General anesthesia is mostly used in major operations such as cardiac surgeries, caesarian sections and replacement surgeries.

- It needs to be administered by an anesthesiologist via mask or IV. It will cause the patient to become unconscious and most of their bodily functions to slow or continue with assistance.

- Many patients are intubated for breathing assistance.

- The anesthesiologist monitors certain vital signs during the surgery (explained below) and after the surgery.

Intra-operative and Intra-anesthetic Awareness (1,2)

- While general anesthesia should cause total unconsciousness, there are many cases where patients are able to recall experiences during their operation

- 1 or 2 in every 1000 patients experience this occurrence known as intra-operative or intra-anesthetic awareness, and seems to have a higher incidence with children

- A large multi-center study conducted in the United States in 2004 determined that the frequency of this happening was about 0.13% which translates to around 2000 cases every year.

- In many cases of intra-operative awareness, the patient experiences something inconsequential such as hearing what the physicians and nurses are talking about.

- However, in many situations, patients develop post traumatic stress disorder or depression due to the immense pain they felt during the operation.

- Under these conditions, patients typically experienced insomnia, nightmares, anxiety and flashbacks.

- The reason they developed PTSD was because they were in severe pain but were helpless due the paralysis caused by neuromuscular blocking that was administered to them.

- In a study with 11785 patients who was administered general anesthesia, the incidence of awareness was 0.18% for those who has taken neuromuscular blockers and 0.10% for those who did not. Out of the19 patients who experienced awareness, 7 (36%) said they felt some pain, either at the site of the endotracheal tube (mild soreness) to severe pain at the point of operation.

- The physicians and anesthesiologists need to use proper equipment to monitor anesthesia depth during the procedure, and its effects after the operation.

- About 2% of legal cases against anesthesiologists are due to intra-operative awareness

Patient-related factors

- Age

- Limited cardiac reserves

- drug resistance/ substance abuse

- usage of cocaine, alcohol or benzodiazepines

- history of difficult intubation

- past episodes of intra-operative awareness

Causes and risk factors

- insufficient anesthetic medication due to hemodynamic instability. Some patients cannot tolerate the sufficient dose due to poor cardiac function or hypovolemia

- some patients may have different anesthetic requirements based on the function of their target receptors. This also refers to patients who have a greater need for anesthetic drugs (opioid or alcohol users)

- equipment malfunction or misuse

Current options in monitoring anesthesia depth (on-going research on this topic...)

- awareness could still happen in the presence of monitors

- The "Practice Advisory for Intra-operative Awareness and Brain Function Monitoring" ruled brain activity monitors as a practice advisory and not a practice standard so doctors do not completely rely on them for anesthesia depth

- Example of brain activity monitor: BIS (Bispectral Index Monitoring)

- Uses 3 electrodes placed on patient's forehead to record the electroencephalogram (record of brain activity) and generates a number between 0 and 100. If the BIS value is lower than 40, the patient is in deep anesthesia state. If the value is above 80, patient is under light sedation.

- Does not directly quantify level of of consciousness but shows neuronal processing

- Similar devices that analyze brain activity are used to monitor anesthesia depth: AEP (Auditory Evoked Potentials) and the Narcotrend.

- When a patient has experienced intra-operative awareness, they must be assessed and reassessed continuously and referred to the anesthesiologist for follow ups for explanations and resources, such as supportive care or counseling. (2)

Standards for Basic Anesthetic Monitoring according to ASA (3)

1. Qualified anesthesia personnel present in room throughout any procedure that requires anesthesia (general or regional).

2. Patient's vitals (oxygenation, ventilation, circulation and temperature) continually evaluated.

I. Inspired gas - the concentration of oxygen measured by an oxygen analyzer with a low concentration limit alarm in use

II. Blood oxygenation - pulse oximetry w/ variable pitch pulse tone and low threshold alarm

III. Ventilation - Qualitative signs of chest excursion, observation of reservoir breathing bag, breathing sounds. Quantitative monitoring of volume of expired gas. Mechanical ventilator → audible signal when alarm threshold is exceeded

IV. Circulation - continuous electrocardiogram display from beginning of anesthesia until ready to leave anesthetizing location. Arterial BP and heart rate evaluated every 5 mins. Pulse palpation, heart sounds, monitoring of a tracing of intra-arterial pressure, ultrasound peripheral pulse, pulse plethysmography or oximetry

V. Body Temp - monitored when clinically significant changes in body temp happen

Need Statement (Ongoing...) < team input >

Problem: 0.1-0.2% of surgeries result in intra-operative awareness. This causes PTSD in these individuals and account for 2% of legal claims against anesthetists

Population: Patients undergoing surgery that require general anesthesia, predominantly in the United States

Outcome: To decrease the number of patients who experience intra-operative awareness while under anesthesia

Scoping from general to specific:

Specific

- A method to prevent the 0.1-0.2% of cardiac and replacement surgery patients in the United States who experience intra-operative and intra-anesthetic awareness and consequently develop post-traumatic stress disorder.

- A way to reduce the percentage of patients in the United States who experience intra- operative and intra-anesthetic awareness while under general anesthesia.

- A method to reduce the incidence of awareness for anesthetized patients in the United States. General

Initial list of Stakeholders < team input >

- American Society of Anesthesiologists (ASA)

- Task Force on Intra-operative Awareness

- Patients undergoing surgery

- Patient families

- Anesthesiologists

- Other health care providers (attending physician, nurses)

- Insurance companies

- Hospital Administrators and Governing Bodies

- American Association of Nurse Anesthetists (AANA)

- Anesthesia Awareness Registry