The present study was conducted at a cardiovascular subspecialty center in west of Iran in 2017. The HFMEA was used for the identification and analysis of potential risks and errors in the anesthesia process of open heart surgeries. The fishbone diagram was used to identify the cause and effect relationships. The steps of HFMEA were as follows: (1) define the HFMEA topic; (2) assemble the team; (3) graphically describe the process; (4) conduct a hazard analysis; (5) actions and outcome measures; and (6) follow-up on actions taken.
After determining the process of cardiac anesthesia (step 1), a multidisciplinary team of 6 - 8 experts and management specialists, including anesthesiologists, cardiac surgeons, quality improvement experts, industrial engineers, anesthesia nurses, surgical technologists and nurses, and secretaries, was recruited, and the final results were recorded in the HFMEA worksheet (step 2). Next, a graphic representation of all anesthesia processes and activities in open heart surgeries was prepared and numbered. Overall, four major processes were identified: (1) preoperative assessment for general anesthesia; (2) induction of anesthesia; (3) maintenance of anesthesia; and (4) transfer of patient to the intensive care unit (ICU) (step 3).
Next, the sub-processes and activities were determined. In step 3, all failure modes for each activity were identified. In step 4, the modes were prioritized, as shown in
Table 1. The mode of failure was determined and recorded in the worksheet. With respect to the severity and occurrence of failure, a rating of one to four was considered; the minimum score of each failure mode was one, and the maximum score was 16 (
Table 2). For example, in the second process (induction of anesthesia), the first sub-process is “non-invasive monitor connection”; one of the activities is “connecting the pulse oximeter”; and one of the failure modes is “inappropriate location of the pulse oximeter probe”. In this case, the severity score is one, and the probability score is two; by multiplying the score, the risk score can be determined, which is equal to two in this case. This stage of risk analysis is known as quantitative risk assessment.
| Scores | Dscription |
|---|
| Hazard score | | |
| Catastrophic | 4 | Death or major permanent loss of function, suicide, rape, hemolytic transfusion reaction, and surgery/procedure on the wrong patient or wrong body part. |
| Major | 3 | Permanent lessening of bodily function, disfigurement, surgical intervention required, and increased length of stay for three or more patients. |
| Moderate | 2 | Increased length of stay or increased level of care for one or two patients. |
| Minor | 1 | No injury, no increased length of stay, and no increased level of care. |
| Probability rating | | |
| Frequent | 4 | It may happen several times in one year. |
| Occasional | 3 | It may happen several times in one to two years. |
| Uncommon | 2 | It may happen sometime in two to five years. |
| Remote | 1 | It may happen sometime in five to 30 years. |
| Probability | Severity of effect |
|---|
| Catastrophic | Major | Moderate | Minor |
|---|
| Frequent | 16 | 12 | 8 | 4 |
| Occasional | 12 | 9 | 6 | 3 |
| Uncommon | 8 | 6 | 4 | 2 |
| Remote | 4 | 3 | 2 | 1 |
In the next step, the failure modes were investigated, using a decision tree algorithm by asking three questions about criticality “is the failure mode a disadvantage in the process?”, controlled mechanisms “does an effective control measure exist for the failure mode?”, and detectability “can it be discovered by an operator under a normal system operation?”.
After identifying major failure modes, the root causes were searched; otherwise, the failure mode was not further examined (qualitative analysis).
At the end of the fourth step, if the results showed that the process must be continued, we identified and addressed the causes of numbering them. By further data collection and analysis of the cause and effect, the root causes of the failure modes were identified and divided into six groups of “manpower”, “equipment”, “method of action”, “measure”, “environment”, and “systems and materials”. The fifth step included the design and solutions. According to previous studies, medical teams try to make appropriate decisions to eliminate, control, and determine the causes of failure modes, and appropriate corrective measures are designed to control or eliminate the failure modes. Finally, in the sixth step, a follow-up of the previous steps was carried out.