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Incident Reports

Perfusion Incident Reports

Clinical perfusion is a complex practice with recognized inherent risks. An incident is an event that is likely to happen. In other words, these incidents should not have happened. The level of safety in perfusion is high but improved incident reporting may help to further improve practices.

Cardiopulmonary bypass is an effective modality to facilitate cardiac surgery, patient outcomes can be negatively influenced by the occurrence of perfusion incidents. Although techniques and safety devices create a relatively secure environment for CPB, lower incident rates may be achieved with further improvements.

The use of safety devices like low-level alarms, bubble detectors, arterial line filters and written checklists made today CPB better, more reliable and appropriate than in earlier days. The knowledge and education of perfusionists today and the increased understanding of CPB physiology should mean an improved quality of CPB with better outcomes for the patient. There is more equipment in use and thus more distractions on the heart lung machine and in the operating room. There are more complex Cardioplegia delivery systems, hemoconcentrators and cell savers to be looked after

Perfusion surveys conducted earlier to identify safety techniques and incidents related to cardiopulmonary bypass (CPB) revealed the highest number of incidents and occurrences being haematological in nature i.e. protamine reactions, coagulation problems protamine-induced circuit clotting post bypass. Human error is the cause of most incidents like air embolus in a circuit not reaching the patient, accidental cannula displacement, hospital power failure and oxygenator membrane leaks. Device related incidents like heater/cooler failures, urgent return to bypass following circuit disposal. The rate of occurrence of an incident resulting in a serious injury or death was one for every 1300-1400 procedures

Perfusion Incident reports are taken from the web based. The content should be informative and hopefully encourage similar sharing from the perfusion community.

Perfusion Incident Reports

60 year old 80kg male patient. Once Cardiopulmonary bypass (CPB) commenced, there were very high pre-oxygenator P1 line pressures in the bypass circuit (450mmHg). The oxygenator was a Medtronic Fusion. P2 post-oxygenator pressures were within 'normal' range. All potential causes were eliminated but it persisted

The high P1 pressures were not resolving and the p02 oxygen measurement started to fall gradually, although not compromising patient oxygenation. Clotting levels were within range and no clots were seen in the oxygenator. The surgeon was kept informed and the situation monitored before progressing with operation. The decision was made to change out the oxygenator. The anaesthetist was informed and the patient was ventilated conventionally.

CPB was stopped and the oxygenator changed. CPB recommenced and the same high P1 pressures seen again but with no compromise to oxygenation so bypass was continued and monitored very closely. After 30 minutes, the pressures fell to 'normal' levels and remained that way for remainder of the bypass. It was also noted that patient haematocrit on CPB was high (38%) and following discussion with the anaesthetist the patient was diluted with the addition of crystalloid.

Post CPB and protamine, a distal vein graft needed repair and heparin was administered and CPB recommenced. P1 and P2 were both within 'normal levels'. As high P1 pressures seen with both devices on initial use, this was suggestive of a patient specific incident. No untoward effects were noted in the post-op period.

Action taken (includes any action by patient, or healthcare professional, or by the manufacturer or supplier)

First oxygenator returned to Medtronic for evaluation. No fault was found with the oxygenator.

In-house discussion:

Following the incident there was a feeling that perhaps the oxygenator was changed out too soon and high pre oxygenator pressures would have stabilised.

Details of incident/Nature of defect

S3 pump control knob unresponsive and unable to increase or decrease blood flow on bypass. E62 error noted on control panel. RPM remained fixed but flashed visibly to 0 RPM whilst blood flow readings remained constant.

If control knob turned to reduce or increase RPM, there was no response however, LED dot marked the current RPM value.

Details of injury (to patient/healthcare professional) - No injury to the patient.

Action taken (includes any action by patient, carer or healthcare professional, or by the manufacturer or supplier)

  • The fault occurred 10 mins before the end of bypass during de-airing of the heart after mitral surgery.
  • The surgeon informed of fault and second perfusionist brought into theatre for support.
  • Unable to reach calculated flow, blood gases were monitored closely to ensure adequate perfusion.
  • Patient tolerated enforced low flow levels.
  • De-airing of the heart performed using clamps to control blood outflow from the pump unit.
  • Patient weaned from bypass safely again using clamps.
  • Pump rebooted once safely off bypass which cleared the fault.
  • Critical incident reported at local level.
  • Heart lung machine removed from service and colleagues informed of incident.
  • Sorin engineer called to investigate and replace the faulty unit. Thought to be a fault with the drive unit not the control panel.

Details of incident/Nature of defect

Before bypass a small amount of fluid was noticed on the floor beneath the oxygenator, although this was believed to be condensation. On bypass a small amount of blood was noticed to be leaking from the oxygenator fiber block. The volume was minimal, approximately one drop every 5mins, the surgeon was informed and it was agreed to continue the case without further action unless the leak volume increased.

Details of injury (to patient/healthcare professional):None

Action taken (includes any action by patient, carer or healthcare professional or by the manufacturer or supplier)

The case proceeded without any intervention. Following the procedure the oxygenator was flushed and retained for analysis by the supplier. The subsequent report from Medtronic stated the following

  • The case proceeded without any intervention. Following the procedure the oxygenator was flushed and retained for analysis by the supplier. The subsequent report from Medtronic stated the following
  • 'At Medtronic's Quality Laboratory, inspection showed a blood path through the mandrel-to-heat exchanger bond. No fiber leak was observed. The leak in this case was coming from a mechanical joint and clearly not a 'water to blood' leak across the heat exchanger. This was a leak path to the outside of the device due to a bonding issue that has since been corrected in production, you can see from the diagram where the leak path to the outside of the device is located and from where the Affinity in question was leaking.
  • Medtronic has identified that mandrel-heat exchanger bond leaks are most likely related to a UV adhesive void in the bond joint. In response to these leaks, an internal corrective action was initiated and resulted in improved manufacturing process. The mandrel is actually a mechanical joint between two pieces of plastic bonded together. It is the mating joint where the heat exchanger is attached to the oxygenator bundle, last step in the assembly process. The diagram shows where the joint (i.e. mandrel) is located. The joint is designed so that it is always under positive pressure and leaks from the inside out, thereby being a fluid leak from the blood side of the oxygenator to atmosphere.'

resource

Details of incident/Nature of defect

During cardiopulmonary bypass (MVR+CABG) blood was seen in the water lines that connect the heater cooler unit to the oxygenator's heat exchanger. This obviously suggests a leak in the heat exchanger and the patients' blood and water could be potentially mixing. The water lines were immediately switched off and disconnected, and the consultant surgeon informed. The recommended procedure is to change out the oxygenator following heat exchanger leak. However, the consultant cardiac surgeon felt that this was not a safe option at the time as the oxygenator was still working, so we remained on bypass. The cross clamp was removed and the patient was rewarmed from 28Centigrades to 34Centigrades using the separate heat exchanger on the cardioplegia circuit and two fluid warmers donated by the anaesthetic team. Once the patient reached 34Centigrades , the patient was ventilated and bypass was terminated and the oxygenator replaced with a new one. Bypass was re-commenced and the patient fully rewarmed. Bypass was discontinued and the patient was stable. It should be noted that a full heat exchanger leak test was performed before the bypass circuit was primed and no fault was detected (water circulated at 37oC for 5mins prior to adding prime solution, no pressure test).

Details of injury (to patient/healthcare professional):Unknown. Patient stable and extubated the following morning.

Action taken (includes any action by patient, carer or healthcare professional or by the manufacturer or supplier):

Microbiology was informed and antibiotics were given. A water sample from the heater cooler unit was sent to the lab for investigation, and the oxygenator was sent to Medos.

Details of incident/Nature of defect

Patient commenced on cardiopulmonary bypass, flow/line pressure normal, on bypass just over 1 minute venous blood appeared very blue as did arterial blood, had just cross clamped and cardioplegia just running, informed surgeon and anaesthetist problem with blood gas blender. FiO2 at 60%, and gas flow at 2.5L, on commencing bypass. Adjusted FiO2 to 100%, and gas flow to 10L, palpated end of air/O2 line with finger, very little air/O2 going into oxygenator. Traced line back to vaporiser, large tear observed on tubing at back of the vaporiser, line seemed perished. Anaesthetist put tape/sleek on tubing and a tie wrap, which solved problem. Poor oxygenation for over 2minutes, blood gases were pO2=50 mm Hg, PCO2=51 mm Hg. Repeat blood gases after the repair were PO2=399 mm Hg, PCO2=54 mm Hg. Adjusted FiO2 and gas flow then repeated blood gases were PO2=222 mm Hg, PCO2=34 mm Hg. Case continued without incident, exited CPB without problem.

Details of injury (to patient/healthcare professional):None.

Action taken (includes any action by patient, carer or healthcare professional or by the manufacturer or supplier):

Replaced defective tubing, must replace/check tubing more frequently.

Independent root cause analysis (RCA) of the incident causing the death of a Pediatric cardiac surgery patient at united Bristol health care NHS trust on 27 may 2005

The Gritten Report was published by the University Hospitals of Bristol National Health Service Foundation Trust on the root cause analysis (RCA) of the death of a 5 month old infant undergoing complex cardiac surgery on May 25, 2005. A police investigation and coroner's inquest found a verdict of 'unlawful killing'. In English law unlawful killing means that the killing was done without lawful excuse and in violation of criminal law including murder, manslaughter and infanticide. The finding of unlawful killing must be beyond reasonable doubt; that is, the evidence must be overwhelmingly obvious that death would result, that no other thing is taken into account. Otherwise a verdict of accidental death or death by misadventure would apply. The death was the result of a calcium overdose by a perfusionist that caused irreversible brain damage and subsequent death the day after surgery. The hospital put safeguards into place immediately to minimize any similar incidents happening again.

The RCA report concluded that this was a unique but avoidable incident and that the problems of greatest significance were:

  • Lack of regulation of perfusion as a profession: ".... little in the way of legislation governing their practice or conduct."
  • Inconsistently applied perfusion protocols and guidance.
  • Lack of perfusion checklists and double-checking.
  • Poor perfusion team communication.
  • Inadequate risk assessments and performance management by perfusionists.

Examples of incidents that have occurred

The following are four examples of published or known incidents.

  • During CPB, the perfusionist was handed a unit of blood to add to the reservoir. Allegedly the blood had been checked by the circulating nurse and the second perfusionist. A few minutes after it had been added, the nurse realized that another patients' blood had been given. Surgery was completed with the patient undergoing two complete blood exchanges while on bypass. He developed generalized DIC in the ICU and died on the second post-operative day. A lawsuit was filed against the perfusionist, hospital and surgeon and was settled out of court for an amount in excess of (equivalent to) EUR 665.000 or $1,064,000 USD.
  • In connection with a mitral valve replacement, the surgeon inserted a vent into the left atrium via the left superior pulmonary vein. When the vent sucker was turned on a large amount of air was pumped into the heart because the vent line had been positioned incorrectly (reversed) in the pump head. The aortic X-clamp was not in place at the time. The patient suffered severe neurological damage. A lawsuit was filed against the perfusionist, surgeon and hospital and was settled out of court for an amount in excess of (equivalent to) EUR 830.000 or $1,300,000 USD.
  • During CPB, the perfusionist allowed the reservoir to empty when the surgeon accidentally occluded the venous line. Air was pumped to the patient who subsequently died. An arterial line filter was in use but the perfusionist was using the purge port to measure pressure. As such there was no continuous purge to the reservoir. A low level alarm was also in use but failed to function. The patient had significant neurologic damage. A lawsuit was filed against the perfusionist, hospital and surgeon and was settled out of court for an amount in excess of (equivalent to) EUR 235.000 or $376,000 USD.
  • Contrary to the oxygenator instructions for use and standard and known operating procedures, the perfusionist closed the reservoir vent port during perfusion. The reservoir pressurized and emptied resulting in massive air entering the heart from the venous line. The patient was pronounced dead on the table (DOT). A lawsuit was filed against the hospital, surgeon, perfusionist and oxygenator manufacturer. It was settled out of court for an amount in excess of (equivalent to) EUR 665.000 or $1,064,000 USD.

Trouble shooting deals with an unanticipated failure after the failure occurs by

  • Identifying the failure
  • Choosing qualified investigators
  • Gathering the facts
  • Identifying the hazards
  • Identifying why the controls failed
  • Making plans to prevent future events
  • Assessing the results of the plan
  • Informing all interested players
  • Performing follow-up investigations to ensure compliance