Sleep disorder sees man's careless driving conviction set aside

David Savieti suffered a cardiac arrest after his vehicle crossed the centre line and crashed...
David Savieti suffered a cardiac arrest after his vehicle crossed the centre line and crashed into another vehicle after falling asleep at the wheel. Photo: ODT
A hospital worker who was convicted of careless driving has had his conviction set aside after being diagnosed with a severe sleep disorder.

David Savieti suffered a cardiac arrest after his vehicle crossed the centre line and crashed into another vehicle after falling asleep at the wheel more than three years ago.

He nearly died in the aftermath of the crash that happened in the Auckland suburb of Mt Roskill. The female driver of the other car was also injured.

During his recovery in hospital, Savieti was diagnosed with obstructive sleep apnoea (OSA), a medical condition that causes poor quality sleep and can lead to excessive daytime sleepiness.

In 2018, Savieti was convicted of careless driving causing injury in the Auckland District Court and sentenced to 80 hours' community work and ordered to pay reparation of $665.50. A later appeal to the High Court in 2019 was dismissed.

However, in a judgment released yesterday, the Court of Appeal has set aside Savieti's conviction as the evidence did not establish beyond reasonable doubt that Savieti was driving carelessly.

Evidence provided in the appeal referenced how one of the consequences of prolonged chronic tiredness was that the sufferer was unable to recognise they were tired, given its regularity.

From this, retired neuropsychiatrist Dr Peter Fenwick outlined it was unlikely Savieti would have realised he might fall asleep at the wheel.

In the initial trial, the prosecution argued Savieti was careless because, even though he did not know he had OSA, he was driving when he would normally be having an afternoon nap.

However, respiratory and sleep specialist Dr Andrew Veale - who gave evidence on Savieti's behalf - argued that there were a number of factors that indicated Savieti would have had no concern about driving, in particular that Savieti claimed he had never fallen asleep at the wheel and crashed.

Veale told the Herald said he was glad Savieti's conviction had been set aside.

"I thought it was inappropriate that he was convicted in the initial court case."

Veale, from the NZ Respiratory and Sleep Institute, described OSA as a disorder where muscles in the throat relax, leading to a complete obstruction of the throat, prohibiting breathing. In response, the brain is woken - or goes through an arousal - and breathing is restored briefly before the process begins again.

Even though the person is often not woken during this process, it caused repeated sleep fragmentation, leading to people becoming sleepy during the day.

"That can range from people who just aren't firing on all cylinders, right through to people you have to wake two or three times in the midst of a conversation," Veale said.

Veale said Savieti's OSA was very severe, which saw him stop breathing or partially stop breathing when sleeping 114 times per hour - almost two times per minute.

Roughly 9 per cent of people between 30-60 years of age suffered from OSA. The severity of Savieti's case was uncommon but not rare.

As OSA was more common in Māori and Polynesian men, Veale said Savieti had little indication he had a sleep disorder.

"[Savieti] had not being diagnosed with a sleep disorder, all his family members snored and had obstructions as well, which is very common in Polynesian families, so there was no clue to him that he had a disorder which might result in him having a crash.

"His background and his family had normalised what you or I might have thought was abnormal."

Veale also explained how the transition from feeling tired and sleepiness could happen in an instant, giving people little opportunity to act.

Citing obesity as one of the chief causes of OSA, Veale said societal factors which enabled obesity should be targeted. However, he noted the issue was complex.

"This is why it's so difficult to create regulation because most sleepy people who have a crash, don't have sleep apnea, and the majority of people with sleep apnea will never have a crash."

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