It’s ‘a possibility’ driver fell asleep
THE trial of a lorry driver who pleaded not guilty to dangerous driving causing the death of a council worker heard that it was “most likely” he fell asleep at the wheel.
Evidence was heard that Vlastimil Zachar had an undiagnosed sleep condition at the time and has since been diagnosed with severe Obstructive Sleep Apnoea (OSA) since the crash on 13th August 2015.
The lorry Zachar was driving veered into the hard shoulder at Ballyhealy townland, Hollybrook, Castlebaldwin killing council worker Padraig Noone who was with colleagues cutting grass along the verge of the N4.
Called by the defence, Dr John Garvey, Consultant Respiratory Physician and Clinical Director of the Sleep Laboratory at St. Vincent’s University Hospital told the court last Tuesday that people driving with the condition had an increased risk of road traffic accidents.
The possibility of an accident for a person with the condition was two fold up to eight fold, according to Dr Garvey.
“Accidents when they occur tend to be more severe with an increased risk of injury to other people.
“There are often no brake marks, and are one car collisions,” he explained.
The doctor performed a full sleep test on Zachar on 22nd March this year.
The test was performed overnight with continuous monitoring including videoing, monitoring of eye movement, breathing, heart rate and chest and abdominal movement.
Dr Garvey said the test showed the defendant held his breath for 61 times per hour during sleep, for approximately seven seconds each time.
He added that a person with no signs of sleep apnoea would hold their breath for five times per hour.
The doctor explained that the condition happens during the night when the upper airway collapses or partially collapses.
He outlined that if a person has the condition it results in the disruption of the quality of sleep, results in a person sleeping during the day, impacting on mood and the ability to drive.
Zachar also took part in a (contd) sleep latency test, a day time test monitoring how long it takes someone to fall asleep when given the opportunity.
If a person falls asleep quickly, in less than 10 minutes, they are considered to be “significantly sleepy.”
Zachar took 8.1 minutes on average to fall asleep and he was viewed as being “moderately sleepy” during the day. In his evidence the doctor said somebody who is sleepier than they should be, is not just at an increased risk of falling asleep, but of “having micro sleeps.”
He added that people can have micro sleeps without warning.
Zachar admitted to the doctor that he remembered having micro sleeps previously.
Doctor Garvey explained that people who have micro sleeps could experience them for up to 30 seconds and would not be aware of their surroundings. He said the accused did not remember falling asleep on the day of the accident but only remembered waking up and seeing a dead person.
It was heard that Zachar is now using a Continuous Positive Airway Pressure (CPAP) device for the disorder, which blows air into his airways to prevent them from collapsing at night.
It was noted by Dr Garvey that since treatment, Zachar feels more refreshed and no longer falls asleep on three hour train journeys.
In cross examination it was heard that Zachar had no symptoms of narcolepsy but claimed to have had “a number of micro sleep episodes” that occurred while driving long distances on a motorway. However, the following day, last Wednesday 5 th December, a prosecution sleep expert didn’t rule out the possibility that Zachar fell asleep from overwork.
Called by the prosecution, Consultant Respiratory and Sleep Specialist at Beaumont Hospital Professor Richard Costello reviewed the sleep test carried out on Zachar by Dr Garvey last March.
Prof. Costello agreed with the diagnosis of Obstructive
Sleep Apnoea and didn’t challenge the conclusions reached by Dr Garvey.
He told Ms Orla Crowe SC, prosecuting, that he sought to understand why the study was done and studied the amount of time it took Zachar to fall asleep.
“I didn’t see evidence of narcolepsy,” he told the jury of four women and eight men at Sligo Circuit Criminal Court.
Narcolepsy is a condition characterized by an extreme tendency to fall asleep whenever in relaxing surroundings.
The professor said Zachar slept for five hours 53 minutes during the sleep test at St Vincent’s, after taking 24 minutes to fall asleep.
He said Zachar had a “relatively normal sleep profile” but “the most notable feature” was that he stopped breathing many times with 210 “respiratory events”, one every two minutes.
He said this was “consistent with OSA.”
The court heard that there are three symptoms for sleep apnoea: snoring, daytime sleeping and witnessed apnoea. “It does not appear that this was commented on by his partner in the past,” said Prof. Costello.
He said the term “micro-sleeps” was not a term he used in his practice.
He then told the jury that it was “entirely possible that he fell asleep due to sleep apnoea but I want to point out that insufficient sleep from excess work is another possibility.”
The court heard the kernel of the issue was whether Zachar fell asleep on the day from sleep apnoea or insufficient sleep.
Prof. Costello said people with undiagnosed OSA become accustomed to being sleepy and “just think they’re getting on, or are unfit.”
“It’s entirely possible that this man had OSA and wasn’t aware of it,” he said.
Cross-examining him, Ms Eileen O’Leary SC for the defence, put it to him that Zachar had a latte at a service station beforehand.
She asked if it appeared Zachar had OSA for long but Prof. Costello said he couldn’t comment on how quickly he developed the condition.