While the negligent administration of anaesthesia to 86-year-old Chow Fong Heng by a nurse at the Singapore General Hospital (SGH) two years ago was a “gross error,” it did not directly lead to the death of the elderly woman, according to Coroner Marvin Bay on Wednesday (19 Dec).
The “gross error” he mentioned specifically referred to the “calculations” made by the nurse who was responsible for administering the anaesthesia process, who had “apparently” confused “the application of units of milligramme and millilitre, and mistaken the dose selection for the rate selection” with regards to the amount of lignocaine that ought to have been given to Madam Chow.
The nurse would be required to input 41.7 mg per hour for dose selection in the intravenous smart pump, while she would be required to key in 4.17ml per hour for rate selection in the machine.
She admitted in the inquiry that she “had mistaken” the dose selection for the rate selection, which resulted in her having administered 10 times the required dosage to Madam Chow.
The nurse also admitted that she did not make any revisions or confirmation with her colleague as to whether the settings had been correctly entered, and had instead attended to another patient after keying in the figure and continued with her routine duties afterwards.
Coroner Bay expressed concern over the knowledge that the nurse was tasked to administer the anaesthesia to Madam Chow despite being “unfamiliar with the (system),” considering “she had limited exposure to its usage” and would be prone to making grave errors as a result, from a logical standpoint.
“There should be no doubt that misadministration of sedative drugs can have extremely dire consequences,” said the coroner.
Findings by a forensic pathologist had shown that the elderly patient’s death resulted from septicaemia, or blood poisoning, and multi-organ failure.
Channel NewsAsia reported that according to a testimony by a medical officer from SGH’s National Heart Centre, “severe overdoses of the anaesthetic called lignocaine can result in seizures, morbidity and mortality”.
However, Coroner Bay maintained that Madam Chow died of natural causes.
Madam Chow’s medical records indicated that she suffered from terminal renal disease, on top of other conditions such as hyperlipidaemia, or having high levels of cholesterol in her blood, and hypertension.
Dr Ong Hui Shan, who reviewed Madam Chow’s condition after the overdose took place, revealed that while the patient’s mental state had “deteriorated,” the lignocaine toxicity was immaterial in relation to Madam Chow’s death, as she was already suffering from “life-threatening conditions which included sepsis, renal failure and ischaemic heart disease”.
Madam Chow was admitted to SGH on 24 May two years ago after a special site on her left arm created to facilitate her dialysis was infected and contained pus. Pathogens were later discovered in her bodily discharges.
A National Heart Centre doctor prescribed lignocaine for her treatment after discovering that Madam Chow’s heartbeat became rapid six days after the infection on her arm was discovered.
The Straits Times reported that the nurse, or Nurse C as she was referred to in the inquiry, administered the anaesthetic fluid on 31 May. Two hours after the error took place, The Renal Intermediate Care Centre was given a notification regarding the mistake.
Speaking to Channel NewsAsia, chief of nursing at SGH Dr Tracy Carol Ayre said: “We are sorry for the demise of Mdm Chow and regret the incident even though it did not directly contribute to her death”.
“SGH has informed the inquiry of steps taken to remind and reinforce the importance of strict compliance of requirements imposed in counterchecking where medications and sedatives are administered, and also in ensuring that nurses have the requisite competency and knowledge when tasked to administer medication to patients,” she added.
Dr Ayre also said: “We have also shared the lessons learnt with all our nurses, as part of our ongoing efforts to achieve zero harm for our patients. Appropriate action has been taken against the staff involved.”
Despite Dr Ayre’s statement regarding “appropriate action”, SGH confirmed that the nurse has not been dismissed from the hospital.