The ever evolving role of technology in healthcare services now allow hospitals to diagnose faster, with greater accuracy than ever before and increasingly in a manner which is least invasive. It allows hospitals to treat better and help patients recover faster. Most of the processes in high risk clinical areas of a hospital like the operating room, intensive care area etc., involve usage of medical equipment. But faulty medical equipment or use of equipment in a manner other than in which it was intended to may lead to serious disability or death of patient. Few examples are wrong delivery of drug through non calibrated infusion pump, and patient suffering from a burn injury due to loose contact with patient plate while using electrosurgical equipment inside operating room. The NABH accreditation standard ROM 6a, mandates that top management of hospitals should ensure proactive risk management across the organisation. As per NABH accreditation standard FMS 1a, the hazard identification and risk analysis (HIRA) exercise is to be conducted by hospital and it should take all the necessary steps to eliminate or reduce such hazards and associated risks. It is mandatory to monitor adverse events and near misses in the hospital, as per NABH accreditation standard CQI 4f.
| Table 1: Numerical Effects Scoring | ||
| Severity (S) | Occurrence (O) | Detectability (D) |
| Major : 3 | Frequent : 3 | Low : 3 |
| Moderate : 2 | Occasional : 2 | Medium : 2 |
| Minor: 1 | Rare : 1 | High : 1 |
The failure mode and effect analysis (FMEA) is one of the tools that can be used for performing HIRA on processes involving medical equipment. The FMEA, like any other process improvement methodology, is a team activity wherein relevant members from different departments will be involved. The goals of FMEA are as follows:
- To identify the failure modes in the process involving medical equipment
- Establish the risks and the consequences of these failure modes
- Identify and implement mitigation strategies for the effects
- Assess the success of the mitigation strategies
- Implement modifications to hospital procedures as appropriate
A hospital-patient related process is any repetitive action that involves transformation of inputs i.e. resources like clinicians, medical equipment, materials into an output i.e. desired service like patient being diagnosed for specific problem. Process mapping will help to identify the major steps in any process. The road map for implementation of FMEA is as follows:
- Select a process or sub process involving medical equipment
- List the potential failure modes i.e. how it may fail
- List the potential effects of the failure
- Estimate the severity number (S) i.e. a numerical measure as given in Table 1 of how serious is the effect of the failure on the patient
- List potential causes or mechanisms of failure
- Estimate the occurrences number (O) i.e. a numerical measure as given in Table 1. It is a measure of probability that a particular failure mode will actually happen
- Estimate the detection number (D) i.e. a numerical measure as given in Table 1. It is a measure of probability that a particular failure mode would be detected by process members
- Compute the risk priority number (RPN = SxOxD)
- Determining corrective and preventive actions i.e. mitigation strategies for the effects including list of individual responsible for completing the action
- Prioritising actions based on the RPN
- Recomputed RPN after corrective actions to hospital procedures as appropriate are computed
The scoring for S, O and D can be taken in a scale of one to 10, but during the cross function teams’ brainstorming session it was noticed that lot of disagreement was happening between the members of group on arriving at a score for any sub process. Hence, it was decided to take numeric measures for S, O and D in the range of one to 3.
| FMEA Computation table | |||||||||
| Worksheet of defibrillator using external paddle | |||||||||
| Steps of usage of defibrillator | Potential failure mode | Effects of failure: Description | Effects of failure: Severity | Effects of failure: Probability of occurence | Effects of failure: Detectability | RPN Number | Significance of failure | Causes of failure | Mitigating strategies |
| Switch on defibrillator | Unit not working | Can’t use unit | Major (3) | Occassional (2) | Medium (2) | 12 | Yes | a) Batteries not charged due to: | |
| 1) Power cord of unit was disconnected | Nursing: Adopt shift-wise visual inspection of defibrillator as part of crash cart checklist and weekly testing unit on test load | ||||||||
| 2) Defective power cord | Clinical Engineer: Regular preventive maintenance and calibration | ||||||||
| 3) Forgot to switch on power outlet | Nursing: Adopt shift-wise visual inspection of defibrillator as part of crash cart checklist and weekly testing unit on test load | ||||||||
| 4) Less functional power | Nursing and Engineering team | ||||||||
| b) Unit malfunctioning | Clinical Engineer: Regular preventive maintenance and calibration | ||||||||
| Apply conductive gel on defibrillator paddle | Improper conductivity between the patient skin and unit | Electrical arc generation leading to burn on patient | Moderate (2) | Ocassional (2) | Medium (2) | 8 | Yes | Paddle surface not clean | Nursing: Cleaning of paddle unit after every usage unit |
| Conductive gel is old | Nursing: Shiftwise visual inspection | ||||||||
| Wrong conductive gel usage | Nursing: Shiftwise visual inspection and SS adoption | ||||||||
| Excessive or low gel application | Nursing/ Clinician: User training | ||||||||
| Select desired energy | Selection knob being loose or non functional | Improper or non selection of energy | Major (3) | Rare (1) | High (1) | 3 | Yes | Hardware malfunctional | Clinical Engineer: Regular preventive maintenance and calibration |
| Position paddles on patient’s chest and deliver shock | Loose connectivity of paddle cable from unit | Improper or non selection of energy | Major (3) | Rare (1) | High (1) | 3 | Yes | Hardware malfunctional | Clinical Engineer: Regular preventive maintenance and calibration |
| Position paddles on patient’s chest and deliver shock | Improper selection of position of paddle on surface | Insufficient energy delivery or electric arc | Moderate (2) | Ocassional (2) | High (1) | 4 | Yes | User Training | Nursing/ Clinician: Increase frequency of user training including refreshers |
| Position paddles on patient’s chest and deliver shock | Improper force exerted between patient skin and unit | Insufficient energy delivery | Moderate (2) | Frequent (2) | Low (3) | 12 | Yes | User Training | Nursing/ Clinician: Increase frequency of user training including refreshers |
FMEA Case Study
The following FMEA case study was done to eliminate the possible failure modes in the use of defibrillator in a hospital. Defibrillators apply an electric shock to establish a more normal cardiac rhythm in patients who are experiencing ventricular fibrillation or another shockable rhythm. The defibrillator is a lifesaving equipment used in emergency situations and any failure/ wrong use while applying electric shock can lead to first or second degree burns or death of the patient.
The process of using a defibrillator with an external paddle whenever code blue is initiated in a hospital is shown in the FMEA computation table. The failure mode for each sub process is tabulated along with effect of each failure, its severity, occurrence and detectability. The possible cause of failure and mitigating strategies is also filled. The rating for S, O and D are fixed based on detailed brainstorming session between nursing team, clinicians, head of emergency department and clinical engineering. The risk priority number for each failure is calculated to understand which sub process needs priority focus. As we can notice, the following sub process needs improvements.
1) Switching on defibrillator
2) Positioning of paddles on patient chest and deliver shock
6) Application of conductive gel on paddle
The team assigned the relevant members to work on mitigating strategy. The hospital team, based on FMEA study, revisited process on maintenance of life saving equipment including defibrillator and improved on timely preventive maintenance and calibration. The frequency of training and visual inspection process during daily rounds also increased. The team decided to review the sub process again after three months, based on the corrective action taken and to revisit the RPN number. The RPN score for step 1, 2 and 6 came down to 6, 4 and 8 respectively, after implementing the corrective measures on ground.
The FMEA for defibrillator helped the organisation to strengthen internal processes and to avoid the potential defect in process, which could have affected patient care. Similar studies can be done in other areas where medical equipment is involved, as part of the HIRA exercise.