R v Pegios

[2008] NSWDC 104

CITATION:	R v Pegios [2008] NSWDC 104 This decision has been amended. Please see the end of the judgment for a list of the amendments.
HEARING DATE(S):	10,11,12,13, 16 June 2008
JUDGMENT DATE:	16 June 2008
JURISDICTION:	Criminal
JUDGMENT OF:	Murrell SC DCJ at 1
DECISION:	See paragraph 26
CATCHWORDS:	Manslaughter by gross negligence - dentist death of patient - no case submission - judge alone trial.
CASES CITED:	R v Misra [2004} EWCA Crim 2375 R v Adomako [1995] 1AC 171 R v Bateman (1925) 19 CR App R 8
PARTIES:	Department of Public Prosecution - Crown Dr G Pegios - Defendant
FILE NUMBER(S):	07/11/0232
COUNSEL:	Mr B Hughes - Crown Prosecutor Mr S Littlemore SC- Defendant
SOLICITORS:	The Office of the Director of Publib Prosecution - Crown Guild Legal - Defendant

IN THE DISTRICT COURT
OF NEW SOUTH WALES

16 June 2008

Coram: Judge H G Murrell SC

R v Pegios

No. 07/11/0232

Decision on No Case Submission

1. On 8 November 2002, the accused, a dentist, performed a dental implant procedure upon Sabatini Catignani. During the procedure, the accused used sedation. Mr Catignani suffered a critical loss of blood oxygen saturation, and died of hypoxic brain damage.

2. The accused is being tried before me, sitting as a judge alone, on the charge that, on 8 November 2002 at Kogarah, he unlawfully killed the deceased (manslaughter).

3. The Crown says that the accused was grossly negligent in that:

(1) while subjecting the deceased to sedation in his surgery, the accused negligently administered excessive drugs, causing the deceased to lose consciousness or become deeply sedated, and thereby risking airway compromise and oxygen desaturation; and
(2) the accused negligently failed to respond appropriately when the deceased experienced oxygen desaturation.

4. There is no dispute that the dentist/patient relationship gave rise to a duty of care (to take reasonable care to avoid foreseeable injury), or that the accused's acts/omissions caused the death of the deceased from hypoxic brain damage.

5. At the close of the prosecution case, the accused submitted that there is no case to answer because, on the prosecution case taken at its highest, there is no evidence capable of satisfying a properly-instructed tribunal of fact:

(1) as to the substance of the relevant duty of care (as to what a fair and reasonable standard of care and competence required);
(2) that the accused negligently breached that duty (rather than simply misjudging the situation); or
(2) that the degree of any such negligence was so "gross" or "wicked" that the accused's conduct amounted to a crime against the State.

The Evidence

6. Loss of consciousness may result in oxygen desaturation (hypoxia) because the patient cannot voluntarily ensure that the airway is clear. If prolonged, hypoxia can damage the brain and heart. Consequently, it is important that a health-care professional administering sedation maintain patient consciousness (if the procedure is being conducted under conscious sedation) and/or monitor oxygen saturation (to prevent a patient undergoing conscious sedation from falling into deep sedation/unconsciousness, or if the procedure is intentionally conducted while the patient is in deep sedation/ a state of unconsciousness).

7. Relevantly, the accused administered the drugs midazolam (a sedative, total amount 17mg) and propofol (an anaesthetic with a sedative effect when given in subanaesthetic doses, total amount 150 mg) and administered nitrous oxide.

8. The accused employed an oxymeter to monitor the oxygen saturation in the deceased's bloodstream. It was set to emit an audible alarm if the deceased's oxygen saturation level fell below 90%. Digital oxymeter readings were displayed continuously and were recorded at five minute intervals by an experienced registered nurse.

9. Associate Professor Woods, a dentist, gave evidence that blood is "fairly saturated" with oxygen if the oxygen saturation is over 95%, and that an oxygen saturation of 90% was not adequate. Dr Viljoen described the accused's baseline oxygen saturation reading of 94% as "mildly hypoxaemic". All expert witnesses agreed that oxygen saturation should be maintained at a level above 90% (at least) and should be monitored by an oxymeter set to emit an alarm if saturation fell to 90% (or, perhaps, 92 - 93%). Below 90%, a patient is considered to be hypoxic, and the oxygen saturation level and the related partial pressure level (a measure of dissolved oxygen in the blood) may fall sharply. There is a high risk of damage below 75 - 80% saturation (Dr Padley). A saturation level of 65% is a critical emergency that will "certainly have an adverse outcome" if it continues for 3 - 4 minutes (Dr Kaplan).

10. According to his statement, during the procedure, when the deceased's oxygen saturation level fell below 90%, the accused interrupted the procedure, extended the deceased's neck to open the airway, and did not recommence the procedure until the deceased's oxygen levels had risen above 90% (paragraph 42 of the accused's principal statement).

11. The accused administered drugs and the nurse recorded the deceased's oxygen saturation levels as follows.

Time	Oxymeter reading	Midazolam	Propofol
8.00	86
8.02	84	1mg
8.10	94	1mg
Surgery commenced
8.14	1mg
8.15	96
8.18	1mg	20mg
8.20	95	1mg	10mg
8.23	1mg	10mg
8.25	96
8.27	1mg	10mg
8.30	95
8.31	1mg	10mg
8.33	1mg	10mg
8.35	84
8.36	1mg	20mg
8.39	1mg	20mg
8.40	89	1mg	10mg
8.41	1mg	10mg
8.45	91
8.48	1mg	10mg
8.50	88
8.52	1mg	10mg
8.55	94
9.00	73
9.05	88
9.10	90
9.15	85
9.20	88
9.25	91
9.30	86
9.35	94
9.40	90
9.45	63

Surgery terminated and emergency procedures instituted.

12. P 21, the 1996 Australian and New Zealand College of Anesthetists/ Royal Australasian College of Dental Surgeons guideline on Sedation for Dental Procedures applicable in 2002, was tendered. It provides:

"Sedation for dental procedures includes the administration by any route or technique of all forms of drugs which result in depression of the central nervous system. The objective of these techniques is to produce a degree of sedation whereby rational communication with the patient is continuously possible , so that uncomfortable and/or stressful procedures may be facilitated. The drugs and techniques used should provide a margin of safety which is wide enough to render unintended loss of consciousness unlikely ." (my emphasis)

13. Associate Professor Woods, a dental practitioner who authored the text "Guide to the Use of Drugs in Dentistry", said that the quantity of local anaesthetics employed "represents a high maximum dose" and that the intravenous doses of midazolam and propofol "appear high but not excessive for a large person in good health". The deceased was a large person in apparently reasonable health for his age, who failed to disclose a heart condition and medication regime that may have been relevant. With the benefit of a complete patient history, Associate Professor Woods was of the opinion that gaseous sedation with local anaesthesia would have been preferable, and that it would have been safer to undertake shorter procedures. Associate Professor Woods considered that the procedure "was simply too long" for the deceased to tolerate.

14. Dr Viljoen, a dental surgeon with more than 20 years experience in administering intravenous sedation, considered that the deceased was an appropriate patient for intravenous sedation in a dental surgery. He said that, with intravenous sedation, a dentist should avoid deep sedation, ensuring that the patient could be aroused easily throughout the procedure. In his experience, it was rare for oxygen saturation to fall below 90%. He expressed surprise at the dose of 17 mg midazolam, comparing it with the 5 mg dose usually required in the absence of the "potentiating effect" of propofol. He described the way in which the accused used midazolam and propofol as "very unusual" and referred to the "synergistic effect" when those drugs were administered together (i.e. the combined effect of the drugs was not additive, but was multiplied). He opined that the simultaneous administration of the drugs was "potentially very likely to cause loss of consciousness, with all the dangers associated with the unconscious airway", and said that "loss of consciousness will almost certainly occur", contrary to the P 21 guideline. He disapproved of the continuation of the procedure after 8:35 am as, from that time, the patient was "mostly hypoxemic".

15. Dr Jackson, a periodontist who has used intravenous sedation in his practice for about 20 years, said that "both the number and dosage of drugs administered in this case were excessive and unlikely to maintain a state of conscious sedation". He considered that 17 mg of midazolam was a high dose. He could not express a view about the propofol dose as he does not use that drug, but he noted the "potentiating effect" of the drug combination. He said that "for a period of almost one hour, the dentist failed to take appropriate action to manage the situation when the pulse oximeter was constantly alarming and the physical signs of hypoxia would have become increasingly apparent." In his opinion, "the physical signs of hypoxia (such as depression of respiration and cyanosis) would have been apparent long before (9.45 am)." Cyanosis is the development of a blue colour in the skin. It is first apparent in the lips, so is clearly visible to an operating dentist. It commences when oxygen saturation is in the range 80 - 85% (on average, at 83%). In Dr Jackson's opinion, the accused should have terminated the procedure after 8:40 am because "stopping the surgical procedure and extending the patient's neck to improve the airway was clearly and demonstrably failing to reverse the situation of a patient becoming increasingly hypoxic". Dr Jackson "absolutely would not have continued" past 9 am. Appropriate action would have included confirming that the patient was conscious and responsive, clearing the airway, administering oxygen using positive pressure ventilation, administering flumazinal to reverse the effect of midazolam, and contacting paramedics.

16. Dr Padley, an anaesthetist experienced in dental procedures, said that the deceased was an acceptable candidate for conscious sedation, but sedation should have been confined to conscious sedation. In accordance with the P 21 guideline, the drug regime should have provided a margin of safety wide enough to avoid loss of patient consciousness. He said that the doses of fentanyl, midazolam and propofol that were administered were "excessive and would be sufficient to render a 67-year-old man unconscious or semiconscious." The combination of drugs was "very likely to have caused unconsciousness", although he could not say that unconsciousness certainly resulted, nor could he say when it occurred. He would have expected a dose of midazolam of up to 5 mg, but said that a lower dose should be employed when the drug is used in combination with an opanoid, such as the accused employed. The propofol should have been administered in small doses and with caution. The deceased was over-sedated and "was at risk of the complications of hypoxia, which are cardiac arrest and hypoxic brain injury". He would have stopped the procedure at 9 am, when the oxymeter gave a reading of 73%, as one should "always assume that the low pulse oxymetry reading is correct and only consider machine error when patient hypoxia has been definitely excluded ". In his view, the periodic interruption of the procedure was an inadequate response as the deceased must have been deeply sedated or unconscious.

17. Dr Kaplan, an anaesthetist who has worked with dentists for 14 years, said that anything beyond conscious sedation was inappropriate in a dental surgery because of the risk of airway obstruction and associated complications. Disregarding the propofol dose, the quantity of midazolam used was excessive. Normally, a maximum of 5 mg of midazolam was required for a lengthy procedure. The maximum that he had used was 8 mg, and that was for a 4 1/2 hour procedure. Further, the drug combination was "synergistic". Propofol "potentiates" the effect (exaggerates the side effects) of midazolam. Dr Kaplan said that the combined effect of the drugs administered "would certainly have made (the deceased) deeply sedated or possibly anaesthetised and there is some evidence that that is the case". In the context of the preceding low readings, the reading of 73% at 9 am would have caused him to stop the procedure, provided that was possible.

Negligence

18. The standard of care required of the accused was that of the reasonable person in his position, ie a general dentist undertaking intravenous sedation in his/her surgery in 2002, who was exercising a fair and reasonable standard of care and competence to avoid foreseeable injury. In order to establish negligence, more is required than medical error or misjudgment.

19. The Crown alleged that a fair and reasonable standard of care and competence precluded the administration of drugs in the quantities and/or combination administered by the accused because that drug regime was very likely to cause the deceased to lose consciousness and a reasonable dentist operating in a surgery in 2002 would not have implemented a drug regime likely to result in a loss of patient consciousness.

20. I accept the accused’s submission that there is no evidence that, in 2002, the P 21 guideline was used and/or accepted by general dentists as the standard to which they should conform. However, all Crown witnesses assumed that the spirit (if not the letter) of the P 21 guideline applied to proper dental practice in 2002. Consequently, the guideline does provide some evidence of appropriate practice in 2002. The guideline is consistent with the thrust of the expert evidence that, in 2002, proper practice for intravenous sedation in a dental surgery required that the patient be maintained in a state of conscious sedation and that, as far as possible, deep sedation or unconsciousness be avoided. The reason for maintaining consciousness is to avoid airway compromise and the associated risk of oxygen desaturation which, at levels below 90%, can fall rapidly, threatening significant cardiac or brain damage.

21. Taking the Crown case at its highest (and disregarding the evidence of Associate Professor Woods), the evidence is that, in isolation, the dose of midazolam greatly exceeded an appropriate dose to maintain conscious sedation and that, when the "synergistic" effect of the drug combination is considered, the drug regime was likely to result in deep sedation, if not unconsciousness. In other words, the drug regime was likely to achieve an inappropriate loss of consciousness that was associated with a serious risk of injury. Consequently, it is open to the court to conclude that the deliberate administration of the drugs in question breached a reasonable standard of care and was not merely a medical error or misjudgment.

22. Similarly, the experts agreed that, because of the degree and duration of oxygen desaturation indicated by the oxymeter (and, according to some, by clinical signs which must have been present), the procedure should have been terminated by 9 am at the latest, and appropriate measures should have been taken to restore oxygen saturation. Associate Professor Woods did not comment on this issue, but he did say that, had the procedure been completed by 9 am, the deceased would have survived. There was a lengthy delay between 9 am and 9:45 am, when the procedure was terminated and emergency action was taken. It is open to the court to conclude that the continuation of the procedure after 9 am went beyond medical error or misjudgment and amounted to a negligent breach of the accused's duty of care to the deceased.

Degree of Negligence

23. The offence of manslaughter requires gross negligence in circumstances where what is at risk is the life of the individual to whom the accused owes a duty of care: R v Misra [2004] EWCA Crim 2375, applying R v Adomako [1995] 1 AC 171.

24. As to the degree of negligence needed to establish manslaughter, in R v Bateman(1925) 19 Cr App R 8 at 11, the Lord Chief Justice said:

"judges have used many epithets, such as "culpable," "criminal," "gross," "wicked," "clear," "complete." But, whatever epithet be used and whether an epithet be used or not, in order to establish criminal liability the facts must be such that, in the opinion of the jury , the negligence of the accused went beyond a mere matter of compensation between subjects and showed such disregard for the life and safety of others as to amount to a crime against the State and conduct deserving of punishment." (my emphasis)

25. Whether medical negligence is so "culpable" or "gross" as to warrant criminal punishment is a matter of degree. As such, it is quintessentially a matter for jury assessment.

26. The application is refused.

17/06/2008 - Catchwords added - Paragraph(s) 0