Date Heard: September 30, 2016 | Full Decision [PDF]
In October 2008, the 48-year-old plaintiff was diagnosed with endometrial cancer. Treatment was to be by way of surgery to remove her uterus, fallopian tubes, and ovaries.
Following the surgery, the plaintiff informed her surgical team that she was aware during the surgery. During the surgery, she experienced extreme pain. She could not communicate this to her doctors. She had an explicit memory of the surgery that could be recalled without any prompting.
The plaintiff underwent a pre-operative assessment by an anaesthesiologist. Her medical history of chronic pain, migraines and fibromyalgia led her to become a chronic opioid user. She also had malignant hyperthermia. Malignant hyperthermia is a hypermetabolic disorder of the skeletal muscle and patients with the disorder can have a life-threatening reaction when exposed to volatile anaesthetics. Patients with malignant hyperthermia can be treated with nitrous oxide and intravenous drugs (Total Intravenous Anesthetic or TIVA) by way of anaesthetic. This condition and the chronic opioid use were the two main factors to be taken into account when planning for the anaesthesia to be delivered during her surgery.
The pre-operative assessment and other available electronic records were reviewed prior to surgery by the two defendant anaesthesiologists G and M.
TIVA delivers general anaesthetic through the bloodstream rather than through ordinary inhaled anaesthetics. It is more difficult to monitor the amount of anaesthetic when using TIVA as compared to monitoring with anaesthetic gases. At the time of the plaintiff’s procedure, there was no way to immediately measure the level of anaesthesia in the blood.
A patient receiving TIVA may be required to be paralyzed during the surgery as well. This was required in the plaintiff’s surgery so that she would not buck or cough. If a patient is paralyzed during surgery the anaesthetist has to rely on less reliable signs that the anaesthetic may be light such as changes in heart rate, changes in blood pressure, whether the patient is sweating and whether the patient is tearing. These are called sympathetic responses. The plaintiff showed no sympathetic signs of awareness during the surgery.
The goals of a general anaesthetic are to achieve unconsciousness, to achieve amnesia, to achieve analgesia, and to achieve muscle relaxation. The overall goal is to get the patient safely and alive through surgery, without awareness, without pain, and without memory of the event. Balanced anaesthetic involves the anaesthetist administering a variety of drugs – hypnotic sedatives, which produce unconsciousness (Propofol is a hypnotic sedative); narcotics that provide analgesia (Fentanyl is a narcotic); benzodiazepines that provide amnesia and muscle relaxants that provide muscle relaxation.
The surgery began at 8:00 a.m. and lasted 2.67 hours. The defendant G was present throughout. The defendant M attended at the beginning of the procedure but did not stay in the operating room. M acted in a supervisory role.
At the time of the surgery, the defendant G was completing a fellowship in cardiovascular anaesthesia. The defendant M was a staff anaesthesiologist who completed a cardiovascular anaesthesiology fellowship in 2006. He was an assistant professor of anaesthesia at the University of Toronto, involved in the teaching of fellows, residents, and students. He was scheduled to perform a procedure that required his hands-on involvement simultaneously with the plaintiff’s procedure.
The surgery began with the administration of nitrous oxide at a rate of 53 per cent relative to the amount of oxygen. This was reduced at approximately 8:45 a.m. to 17 per cent as the surgeons reported that the plaintiff’s bowels were becoming distended.
The plaintiff’s position was that the defendant G administered an inappropriately low dose of Propofol and failed to compensate for the lowering of the nitrous oxide. As to the defendant M it was her position that his supervision was inadequate. The defendant defended on the basis that the treatment was a matter of clinical judgment, the plaintiff’s expert conclusions were arrived at with the benefit of hindsight and in any case the treatment was not the but for cause of the plaintiff’s awareness.
The court undertook a comprehensive review of the law on the standard of care and causation.
It was necessary for the court to resolve two factual disputes that were of significance in determining the liability issues. These were the rate at which the defendant G administered the Propofol infusion and secondly, the manner in which the plaintiff’s pre-operative opioid use was taken into account.
Propofol Infusion Rate
The Propofol infusion rate was set by the defendant G at 50 mcg/kg/min at the beginning of the surgery. The defendant G recorded increases in the infusion rate at 9:15 a.m., 9:50 a.m., and 10:20 a.m. by way of an upward arrow on the anesthetic record. According to the defendant, these were increases of 25 mcg in keeping with the available pump adjustments. In addition the defendant G claimed that he raised the Propofol infusion rate from 50 to 100 at 8:10 a.m. after the plaintiff was intubated. This change was not documented.
The defendant G did not have an independent recollection of the Propofol infusion and relied on his usual routine and practice. He argued that it was his daily practice to start Propofol infusion at a rate of 50 mcg to ensure that the pump was working and assess the patient’s reaction and to then increase the infusion rate to 100 after intubation.
The court acknowledged that the invariable practice of a professional can be given significant weight. However it found that given the inconsistencies between the contemporaneous written record and the defendant’s evidence of his invariable practice, the written record was more reliable in this case. The court also held that the defendant had not been administering anaesthesia unsupervised for a significant enough period of time such that what he describes as his ordinary practice should be given deference.
In Dickie v. Minett, 2012 ONSC 4474 (CanLII), aff’d 2014 ONCA 265 (CanLII) the Court of Appeal accepted that it was appropriate for the trial judge to rely on invariable practice. The court distinguished Dickie from the immediate case in a number of ways. In Dickie, the defendant oral surgeon had been practicing for 20 years during which 30% of his practice involved the procedure in question. The defendant G’s experience was comparably limited, as at the time of the plaintiff’s procedure, he had about 2 years of unsupervised practice of anaesthesia – of which only 5-10 percent involved TIVA. In Canada, he was not licensed to practice as an anaesthesiologist on his own until December 2009. Prior to that time, under the terms of his fellowship, he was required to at least review his anaesthesia plan with the staff anaesthetist who was supervising him. As a result, the court found that the defendant G did not have sufficient experience working independently for the court to be satisfied that he had established an invariable practice, let alone an invariable practice entitled to deference.
Further, in Dickie, the oral surgeon’s contemporaneous notes were supportive of his stated invariable practice. In contrast, the defendant G relied on his evidence of invariable practice to explain away his inaccurate charting and the inconsistency of his version of events with letters written by the defendant M subsequently.
Aside from the lack of evidence supporting the claim of invariable or usual practice, there were some other elements of the written chart and evidence that added to the reasons for the court’s rejection of the defence position that the infusion pump was turned from 50 mcg/kg/min to 100 mcg/kg/min immediately after induction of the patient. In particular, the defendant G wrote the Propofol infusion rate of 50 mcg to cover almost the entire first hour of the procedure. He could have placed an up arrow at 8:10 a.m. but did not do so. This would have been consistent with his charting of the other increases. It would have been simple to do.
Further, in cross-examination the defendant G acknowledged that the only thing he had not charted was his claimed initial increase in the Propofol infusion rate immediately following induction of the plaintiff. For instance, he charted changes in blood pressure every 5 minutes. It did not make sense that the defendant could accurately and frequently chart so many other elements during the procedure but would inaccurately write out the Propofol infusion rate over the first hour of the procedure. The anaesthetic record was otherwise completely accurate. It was therefore reasonable to rely on the written record of the Propofol infusion rate.
Further, both defendants made notes on the patient chart under interdisciplinary clinical notes discussing the plaintiff’s intra-operative awareness, yet neither note dealt with the dosages that she had received during her procedure or the Propofol infusion rate. In the court’s view if the defendants had reviewed the anaesthetic chart and noted such a glaring inaccuracy in charting, they would have made a note contemporaneously to the procedure, rather than first presenting their explanations for the chart several years later after action against them had been commenced.
The total amount of Propofol prepared for the procedure was known, but the defendants did not testify as to the amount that was left in the syringes by the end of the procedure. There was no written record that the defendant G went to check the pump settings (as he claimed) after becoming apprised of the plaintiff’s period of awareness.
Following the surgery, the defendant M met with the plaintiff and then with the defendant G. Subsequent to this meeting, the defendant M prepared an incident report. Under the reason for the incident, it stated Light Total Intravenous Anaesthesia. This was inconsistent with a starting rate of 100 mcg and a finishing rate of 175 mcg as claimed by the defendant G.
The defendant M also met with the Chair, Site Chief, and Chair of Quality Control of the Department of Anaesthesia. Subsequently, he wrote a letter indicating that he and this group had concluded that the plaintiff had received an inadequate amount of anaesthesia. The defendant M also wrote two other letters including a letter to the plaintiff’s physician to guide future anaesthesia. None of these letters made reference to the defendant G advising M following the surgery that he had increased the Propofol to 100 mcg after intubation.
The court was satisfied that, in this case, fact finding must be based on the written record. This finding was made for four reasons: (1) as a result of the finding that there was no evidence to support the defendants’ claim of invariable practice; (2) due to the findings regarding the tenuous nature of the defendant G’s claim that he turned the infusion pump to 100 mcg/kg/min at approximately 8:10 a.m.; (3) due to the finding that the defendant G’s evidence that he checked the pump after the procedure was not reliable; and (4) because the defendant M’s independent recollection was unreliable and inconsistent with his contemporaneous notes.
If there were facts known at the time relevant to the incident, review, and reporting, this should have been documented. It was critical to know what infusion rate of Propofol was administered to the plaintiff for her future care. If the Anaesthetic Record was inaccurate, the court would have expected to see that noted in a written record. It wasn’t.
At the time of the surgery, the plaintiff had a prescription for a morphine variant, M-Eslon, for chronic pain, with a dosage of 90 mg. three times daily. The defendants submit that she informed the defendant G that she was taking a total of 30 to 60 mg. per day. This was accepted by the court, as the plaintiff’s testimony and recollection were inconsistent and also incongruent with the records of other health practitioners.
Standard of Care
There were 4 main issues relating to the standard of care that the court was required to rule upon. These involved the defendant M’s supervision of the defendant G, the plaintiff’s preoperative use of Temazepam, her preoperative use of narcotics, and the administration of Propofol.
The experts agreed that the defendants had all of the information necessary to exercise their clinical judgment and that they turned their minds to the right things when formulating the anaesthetic plan.
The defendant M viewed the defendant G as a reliable, experienced, and independent Fellow. The staffing process at the hospital allowed a Fellow with sufficient experience to carry out a procedure independently.
The defendants met with each other and discussed the plaintiff’s malignant hyperthermia, the use of TIVA, the plaintiff’s opiate intake on the morning of surgery and the implication this would have on the pain medication she would receive during her surgery. They did not discuss specific drugs and doses at any time. They understood that a balanced anaesthesia approach would be used.
The plaintiff’s expert testified that it is up to the staff anaesthetist to make sure that the plan is conducted appropriately,that the plan is being adhered to, that there are no variances from the plan, and that any surprises need to be addressed as well. As the defendant M was responsible, he failed to meet the standard. Specifically, the expert did not testify that the defendant M was required to discuss dosages with the defendant G.
The defence expert testified that the supervisory model used by the defendant M is commonly used at a teaching hospital. A Fellow is a fully trained anaesthetist who will discuss the case with the supervisor, but it is his case to do. If the plan met the standard, the Fellow would be free to go ahead. The Fellow can independently administer the entirety of the anaesthesia. The supervisor can cover the Fellow from another operating room if a problem arises.
The court accepted the evidence of the defence expert on the issue of the standard of care of a supervisor. It was preferred to that of the plaintiff’s expert who had no experience supervising Fellows. The plaintiff’s expert did not identify any specific breach of care, but appeared to impose some form of vicarious strict liability on the supervisor. The court found that the defendant M met the standard of care in his supervision of the defendant G.
The plaintiff was taking Temazepam to help her sleep. The plaintiff’s expert testified that this preoperative use of Temazepam would increase the Propofol requirements. The court found that there was not sufficient cogent evidence to establish on a balance of probabilities that pre-operative use of Temazepam increases Propofol requirements. Therefore, there was no need to consider whether the standard of care required consideration of this aspect of the plaintiff’s medical history and whether this requirement had been breached.
Both experts agreed that the standard of care required a prudent anaesthetist to consider the plaintiff’s pre-operative opiate use in planning her anaesthesia. Initially, the plaintiff’s expert’s evidence was that the pain medicine doses administered to the plaintiff fell below the appropriate therapeutic range applicable to her balanced anaesthesia. The defence expert’s evidence was that it fell within the appropriate therapeutic range.
After cross-examination the plaintiff’s expert agreed that the pain medication the defendant G provided to the plaintiff did fall within the appropriate range. He acknowledged that in 2008, anaesthetists had not come to an agreement on the dosage increase necessary to counteract a patient’s past pre-operative opioid use – there was no formula or actual calculation to predict that. There was no agreed upon percentage increase. He further agreed that, in this respect, where to set the analgesic dose of opioids within the range was a question of clinical judgment in any particular case.
Therefore, the court concluded that the defendant G did not breach the standard of care in his administration of pain medication (narcotic opioid) to the plaintiff.
Both experts agreed that until the nitrous oxide was reduced, the plaintiff had appropriate anaesthetic. Both agreed that the decrease of nitrous oxide was a substantial reduction.
The plaintiff’s expert testified that when the nitrous oxide was reduced from 53 to 17 per cent the defendant G was required to do something to compensate but didn’t. Nitrous oxide at 17 per cent was only 16 per cent of an anaesthetic dose that would prevent half of the patient population from moving to surgical stimulation. Additionally, the nitrous oxide at 17 per cent was providing only 20 per cent of an amnestic dose that was going to produce amnesia in half of all patients. The court accepted the evidence that the standard of care required the defendant G to do something when the nitrous oxide was decreased. This conclusion was based on dose ranges and blood concentration calculations.
The defence expert testified that when a significant portion of nitrous oxide is lost, it is logical to replace it with another anaesthetic agent such as Propofol. However, his opinion that the standard of care had been met was premised on the concurrent delivery of a Propofol dose of 100 mcg to the patient at the time the nitrous oxide was decreased. While he was of the opinion that the administration of Dilaudid at the time of the nitrous oxide reduction compensated for the reduction, this was a view held in the context of a 100mcg dose of Propofol, which was not the case.
In this case, the court had found that the Propofol was not increased from 50 to 100 mcg until some 20 to 25 minutes after the decrease in nitrous oxide.
The defendant G had therapeutic options at the time he reduced nitrous oxide, which included increasing the Propofol infusion rate, giving a bolus of Propofol, use a step down method of administering Propofol, dampening the rate of reduction of nitrous oxide, and increasing the dose of other agents being administered. The plaintiff’s vital signs were stable and she could have tolerated more Fentanyl, Propofol, or Midazolam.
Both experts agreed that the standard of care requires a prudent anaesthetist to select drug dosages carefully and to try to put the patient within the range that the relevant literature would support.
The plaintiff’s expert identified a target range of Propofol blood level concentration of 3-4 mcg/mil while the defence expert gave a range of 2-5 mcg/mil. Both agreed that there was no way to know exactly what infusion rate of Propofol leads to what level of blood concentration of Propofol in any particular patient. Both relied on the Schuttler study to calculate the blood concentration level. Using calculations based on the study showed that at a Propofol dosage of 50 mcg, the plaintiff’s blood concentration level was below the lower limit of even the defence expert’s therapeutic target range.
As the infusion dosage fell below the therapeutic range, this was not an error of clinical or medical judgment where the responsibility is to choose a dose within the range. The defendants were also unable to rely on patient variability as a reason for the plaintiff’s awareness, as again she was not dosed based on average therapeutic doses. The infusion rate of 50 mcg/kg/min was not expected by the literature to lead to a blood concentration level for her within the appropriate range.
The court found that the defendant G did not meet the standard of care in his administration of the infusion of Propofol and specifically that – in the period between the reduction in nitrous oxide and the first uptick in the infusion rate of Propofol (approximately 9:15 a.m.) – the infusion rate was insufficient and below the therapeutic range.
Awareness occurs in approximately 1 of every 1000 patients undergoing general anaesthetic. Both experts agreed that it was not possible to guarantee to a patient that awareness will not occur despite the best of intentions, and that despite the honest and intelligent exercise of medical judgment, an adverse event can still occur.
The court found that the plaintiff’s awareness did not result from unique patient variability. It resulted from the significant reduction of nitrous oxide without the defendant G implementing any of the means available to address the decrease. He failed to administer in this critical period a Propofol infusion predicted to provide a blood concentration level within the therapeutic range. Here there was a discrete loss of an important agent and a delay in implementing a replacement agent at the very time the Propofol infusion was too low to be within the predicted goalposts of blood concentration levels. This all resulted from the defendant G’s actions or inactions.
In all of the circumstances the Plaintiff has established causation on a balance of probabilities.
The quantum of damages had been agreed upon.
Plaintiff counsel: Stephen J. MacDonald and Jill M. Edwards
Defence Counsel: Eric S. Block, Kosta Kalogiros