[16703029]
In april 2207, i wrote to you about a case for which i gave the anesthetic that resulted in the death of a patient associated with the use of a stryker cement restrictor. I have attached a copy of my letter from april 2007. I have also enclosed a copy of a letter that i recently received from stryker in response to this event. As you will see the stryker response has nothing to do with the actual event. Instead of addressing the issue on the cement restrictor, they instead elected to test their retained sample of the cement. This was clearly not a cement issue at all. I wrote to stryker and pointed out this error, but also wanted you to be aware of the manner in which they handled this incident. I would like to provide supplemental information on a fatal incident involving a medical device used in surgery, during an anesthetic i administered at hospital in 2007. I reported my experience in writing to the device manufacturer through their regional representative and also shared my experience with the hospital quality officer who told me that he filed an mdr. I wrote to the manufacturer asking for verification that they indeed received my report, but got no response. The hospital quality officer was not prepared to show me a copy of the mdr he filed and was not in fact completely sure that it was filed, so i would like to independently report these events. We just completed a case review of this event in our anesthesia department peer review meeting, so i actually have more information now than anyone had back in january. I hope you will find this is supplemental information for a file you already have. The patient was a male. The medical device involved was a howmedica 30 mm large bone plug canal sizes 18-22 mm, lot 02190xxnea. Drs. Implanted the device, manufactured by stryker orthopaedics, in the patient's left femur. The use of the device took place in 2007. The patient died ten days later, without ever regaining pre-operative responsiveness. The patient broke his hip on or about eleven days before, and presented for hemiarthroplasty one day later, in the morning. He was alert and stable medically but had a history of poorly controlled hypertension. He received sedation for comfort and had an uneventful spinal anesthetic. He received supplemental oxygen by nasal prongs. The surgeon positioned the patient on his right side for surgery. Additional sedation was administered as surgery proceeded, but the patient would awaken periodically, especially when the surgery produced vibration of the table. The case went uneventfully until the surgeon decided the femoral prosthesis would require cement instead of the previous plan for a press fit. The surgeon next discovered that the size of the cement restrictor or bone plug he wished was not part of the hospital's current stock. Instead he was forced to trip a larger plug. His first effort to place the plug was not successful in getting to the necessary depth inside the femur, so he removed the plug, trimmed it further, and drove it with a mallet in the proper position. With the first placement of the plug, the patient awoke and asked me if there was any way he could see what the surgeons were doing. I told him that it was not possible because of the drapes used to keep the site sterile. A few seconds later, the plug went in for the second time and the patient rapidly became agitated, moving his arms, and no longer responding to my efforts to find out what was alarming him. To keep him under control, i administered a small dose of propofol and then needed to increase his oxygen flow since his oxygen saturation fell from the high 90's to the 80's. As the patient seemed to stabilize, still well sedated, i looked up to see the surgeons starting to apply the cement. In the post anesthesia recovery unit, the patient was somewhat responsive to commands to cough or breath deeply, but required 100% oxygen from a non-rebreathing mask to keep his spo2 in the low 90's. We transferred the patient to the icu where he was soon intubated and ventilated. He had an episode of hypotension that was corrected and then slowly regained good pulmonary function over the next week. The patient underwent a multitude of diagnostic tests including a normal ct scan of his head. A d-dimer test was consistent with a pulmonary embolus. He was evaluated for the possibility of a septic event. In summary, nothing definitive emerged and the patient regained apparently normal cardiopulmonary function, but did not awaken. In consultation with the family, the patient was extubated on the morning 2007, and expired later that day. An autopsy found an area of lung consolidation and an area of subendocardial infarction in his heart. Neither of these findings would have caused the patient's loss of mental function. The medical literature has a number of articles reporting the occurrence of air emboli as often as 35-40% during placement of hip prostheses. The fact that this patient was positioned on his right side made us consider the possibility of a paradoxical air embolus in which air would pass upward through a probe-patent foramen ovale. We found such a case reported from japan. The autopsy reported that his patient did not have a probe-patent foramen ovale. Perhaps air, debris, clot, or fat did manage to cross the capillaries of the lung to reach the left side of the heart to cause diffuse brain injury and also the infarction of the subendocardium. We can only speculate. The autopsy did not report any findings from examination of the brain to explain the clinical course. The surgeon's dictation did not include any mention of trimming the bone plug or placing it inside the femur twice, but this would seem an unintentional omission since the bone plug is not normally a key item in the procedure. Anesthesiologists often encounter agitation during the cementing of a hip prosthesis that we attribute to the plastic moner entering the circulation, but in this case the patient reacted ahead of the application of the cement. Effects of cement moner are normally transient. The manufacturer's representative informally confirmed that the bone plug has a means of venting air so that the air captured in the shaft of the femur is not forced into the patient venous circulation. We have no way of knowing if the vent remained open during the second passage of the plug down the femur. We do know that the fit was tight enough that it required the use of a mallet to position the plug. Since the hip is as high if not higher than the heart during this procedure and since the bone will hold open any veins cut in the reaming prior to application of the plug, the introduction of air seems a possibility worthy of consideration, as noted in "air embolism in hip surgery," anaesthesia 35(9), 858-862 (1980). One might think that it would be possible to create a safer bone plug that deployed after placement in the femur rather than acting as if it where a syringe plunger sliding the shaft of the femur. Thank you very much for your consideration of this incident. As the baby boomers approach the age of common hip fracture in the coming decade, we are going to repeat this type of surgery much more frequently. It would certainly be nice to solve this type of problem now. The response to anesthetics in the elderly has become a hot research topic in my specialty, and i have now begun to wonder how much of the problem of altered mental status following surgery comes not from the anesthetic but the surgery itself.
Patient Sequence No: 1, Text Type: D, B5