P082: HAVE YOU EVER BITTEN INTO SWISS CHEESE? WE CERTAINLY HAVE!
Peter Kovacs, MD; Bernardine Cabral, MD; Zachary Deutch, MD; University of Florida - Jacksonville
Introduction: We present a case of near respiratory arrest in an out-of-OR setting (MRI scanner) which illustrates the “Swiss Cheese” phenomenon of medical errors. No single major factor, but a series of lesser risk factors aligned perfectly, creating a dangerous situation for the patient, who fortunately suffered no significant harm.
Methods/Case Description: A 64 year-old female, 5’6” and 400 pounds (BMI 65), presented to our hospital MRI suite for imaging of her cervical, thoracic, and lumbar spine. Anesthesia support was requested for claustrophobia. The scan was scheduled for noon but the anesthesiologist was unavailable until 2:00 pm due to case overrun in the main OR. The patient was evaluated and general anesthesia via endotracheal tube (ETT) was planned. The Datex/Aestiva MRI machine and MRI-compatible equipment were prepared and cursorily checked. After pre-oxygenation, general anesthesia was induced with propofol and succinylcholine, and a 7.5 ETT was placed without difficulty.
Positive pressure ventilation was not possible after connection of the ETT to the breathing circuit. The bellows did not rise and a hissing sound was audible. A crack and leak were discovered in the plastic cover where inspiratory and expiratory limbs connect. The breathing circuit was disconnected, and an Ambu-bag requested from the radiology personnel. There was no Ambu on the anesthetic machine or in the MRI suite. Within minutes, one was obtained from the adjacent Emergency Department and the patient was successfully ventilated. During the delay, the patient’s oxygen saturation declined (nadir in the 40s); other vitals were unaffected. The anesthesiologist decided to defer the MRI and awaken the patient to assess possible anoxic injury. Fortunately none was evidenced, and the patient was discharged home after a routine recovery in PACU.
Results/Contributory Factors: What were the holes in our cheese?
- production pressure, rushing to make up time
- unfamiliar locale and equipment
- support personnel untrained in anesthetic care
- poor preparation (cursory machine check, failure to verify availability of emergency equipment)
- hyper-obese patient with minimal respiratory reserve
Discussion/Conclusion: This is a cautionary tale, an example of how medical errors of the “Swiss Cheese” variety actually transpire. If one (or at most two) of the contributory factors listed are removed, our near miss does not occur.
If the anesthesiologist checks everything properly despite being 2 hours behind schedule, the machine leak is found before induction.
If the case happens in a familiar location (e.g. main OR), an anesthesia tech and other trained team members are present, as opposed to radiology personnel who are not trained in basic anesthetic care (let alone the complications thereof).
If case is done in main OR, anesthesia machines are checked by anesthesia techs prior to each case, and an Ambu-bag is hanging on back of each one.
If the patient is not morbidly obese, the “acceptable” period of apnea lengthens considerably.
This type of near miss can happen anytime when small pitfalls are allowed to multiply, align, and create a critical situation.