C.VEN/BA-M1/06
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Detailed Proof Table for this specific manufacturer-model (Brand A - Model 1) maintained at the manufacturer-recommended maintenance interval (6m)
Each individual segment of the Summary Proof Tables (Table 5) is provided with a "drill down" link that reveals the Detailed Proof Table shown below. This table shows a breakdown of the various batches of data (in this case four batches) that support the aggregated data shown in the Summary Proof Table. This example is using hypothetical data and is for illustrative purposes only. Please refer to the notes below the table for an explanation of the analysis used to derive the various parameters shown in the table.
This table was last updated on 7-14-17
- Back to Table 5.3HE Critical care ventilators (illustrative hypothetical example) (the Summary Proof Table), to Table 5, Table 1, The database Tables or the Main Page
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Data aggregator/ provider ID code | Facility code | Data batch # | Sample size (# of devices) (N) | Time period (years) (E/N=) (T) | Experience base (# of device-yrs) (E) | Is the size of the experience base acceptable? (Table 11) | # of MR 1 failures (M) | # of PM Code 9 failures (W) | Total # of DR-related failures (M+W=) (R) | MTBF for DR-related reliability (E/R) | Level of Severity of DR-related failure modes | Is the level of DR-related reliability acceptable? (Table 12) | PM Priority level (See Table 12) | # of (PM Code F) SV-related failures (S) | MTBF for SV-related reliability (E/S) | Level of Severity of SV-related failure modes | Is the level of SV-related reliability acceptable? (Table 12) | PM Priority level (See Table 12) | ||||
System S1 | F45 | C.VEN/BA-M1/06/DB1 | 40 devs | 2.0 yrs | 80.0 dev-yrs | Yes - Good | 0 | 1 | 1 | 80 years | LOS 3 (Life- threatening) | Yes - Good reliability and safety | 2 | 40 years | LOS 3 (Life- threatening) | No - Poor reliability and safety | ||||||
Facility F2 | F2 | C.VEN/BA-M1/06/DB2 | 12 devs | 1.0 yrs | 12.0 dev-yrs | No - Inadequate | 0 | 1 | 1 | 12 years | LOS 3 (Life- threatening) | No - Poor reliability and safety | 0 | Undeter -mined (>12 years) | LOS 3 (Life- threatening) | Unknown | ||||||
ISO Contractor C1 | F21 | C.VEN/BA-M1/06/DB23 | 100 devs | 4.0 yrs | 400.0 dev-yrs | Yes - Very good | 2 | 2 | 4 | 100 years | LOS 3 (Life- threatening) | Yes - Good reliability and safety | 1 | 400 years | LOS 3 (Life- threatening) | Yes -Very good reliability and safety | ||||||
CMMS Vendor V1 | F17 | C.VEN/BA-M1/06/DB12 | 500 devs | 2.0 yrs | 1000.0 dev-yrs | Yes - Substantial | 2 | 6 | 8 | 125 years | LOS 3 (Life- threatening) | Yes - Good reliability and safety | 3 | 333 years | LOS 3 (Life- threatening) | Yes - Very good reliability and safety | ||||||
Aggregated data for this man-model at this interval | All sources | C.VEN/BA-M1/06 | 652 devs | 2.3 yrs | 1492 dev-yrs | Yes - Substantial | 4 | 10 | 14 | 107 years | LOS 3 (Life- threatening) | Yes - Good reliability and safety | PM Piority 2* | 6 | 249 years | LOS 3 (Life- threatening) | Yes -Very good reliability and safety | PM Priority 3 | ||||
Analysis
With respect to the experience base being considered acceptable. The reported total of 1492 device-years (line 6 column 6) is considered to be "Substantial" since it is >500 device-years. (Table 11).
With respect to this device being classified as device restoration-critical at LOS 3 (potential for life-threatening injury). Based on the reported total of 14 DR-related failures (line 6 column 10), the MTBF (mean time between failures) for this type of device, when maintained at a 6-month interval is 107 years (1492 device -years/ 14 failures), which makes its DR-related reliability/ safety Acceptable at the "good reliability" level (75-150 years). See Table 12
With respect to this device being classified as safety verification-critical at LOS 3 (potential for life-threatening injury). Based on the reported total of 6 SV-related failures (line 6 column 15), the MTBF (mean time between failures) for this type of device, when maintained at a 6-month interval is 249 years (1492 device -years/ 6 failures), which makes its SV-related reliability/ safety Acceptable at the "very good reliability" level (>150 years). See Table 12
Based on these findings - although potentially-critical this particular manufacturer-model should not be considered a PM Priority 1 device. In spite of the high level of the severity of the outcome if it fails (potentially life-threatening), its demonstrated good - very good level of reliability means that it should be considered a 'PM Priority 2 device. See Table 12
Table 5A Thresholds for acceptability of the size of the experience base (Copied from Table 11 - Still tentative)
Experience base thresholds (tentative) | Amount of data (device-yrs) |
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Inadequate | <50 |
Good | 50-200 |
Very good | 200-500 |
Substantial | >500 |
Table 5B Definitions of the five different levels of device risk (copied from Table 12 - Still tentative)
The level of risk associated with a device failure caused by not completing the device's PM in a timely manner (which increases the risk that the device will fail) is determined by both the level of severity of the potential adverse outcome if the device fails (LOS 1, LOS 2, or LOS 3) and the device's demonstrated PM-related reliability (expressed as an MTBF* or mean time between failures).
So, devices that have at least one high severity failure mode (LOS 3) combined with a demonstrated poor PM-related reliability (MTBF less than 75 yrs) should be considered to represent the highest risk and labeled PM Priority 1 devices.
Devices with better levels of reliability (represented by longer MTBFs) and/or lower severity outcomes should be considered PM Priority 2, 3, 4 or 5 devices. The full hierarchy of different combinations of the worst-case severity of the result of the device failing and the device's demonstrated reliability is shown in the table below.
(This table was last updated on 4-9-16)
Level of potential risk | Outcome Severity Level A, B, C, or D Devices with at least one failure mode with severity level LOS 3 (Life-threatening injury) | Outcome Severity Level E, F, or G Devices with at least one failure mode with severity level LOS 2 (Possible patient injury) | Outcome Severity Level H Devices with at least one failure mode with severity level LOS 1 (Disruption of patient care) |
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"PM Priority 1 device" (potentially) high risk | Poor reliability (MTBF <75 yrs) | ||
"PM Priority 2 device" (potentially) mod - high risk | Good reliability (MTBF 75-150 yrs) | Poor reliability (MTBF <50 yrs) | |
"PM Priority 3 device" (potentially) moderate risk | Very good reliability (MTBF >150 yrs) | Good reliability (MTBF 50-100 yrs) | Poor reliability (MTBF <25 yrs) |
"PM Priority 4 device" (potentially) low risk | Very good reliability (MTBF >100 yrs) | Good reliability (MTBF 25-50 yrs) | |
"PM Priority 5 device" (potentially) very low risk | Very good reliability (MTBF >50 yrs) |
- For definitions of Outcome Severity Levels A thru H - see column 5 of Table 4
Abbreviations | |
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DR | Device restoration, as in the device restoration-related tasks listed in a device's recommended PM procedure. |
SV | Safety verification, as in the safety verification-related tasks listed in a device's recommended PM procedure. |
Level of Severity (LOS) 1 | A device whose failure could be life-threatening i.e. that could cause the patient (or the user) to lose his or her life. |
Level of Severity (LOS) 2 | A device whose failure could cause a patient injury. |
Level of Severity (LOS) 3 | A device whose failure could cause a disruption of care, such as, delaying treatment or diagnosis, or requiring one or more patients to be rescheduled. |
MTBF | Mean Time Between Failures - is the inverse of the device's failure rate. For example, a device that failed twice in nine years has an MTPF of 4.5 years. |