Lethal level of meth in blood

An Ashburton man found dead in a ditch had enough methamphetamine in his blood to kill him, a jury has been told.

Ashburton man Kooly Managki Te Tomo, 28, is on trial at the High Court in Timaru for the manslaughter of Arran Gairns, whose body was found in an Ashburton ditch on June 1, 2014.

Earlier in the trial, the jury heard how Gairns had purchased a gram of methamphetamine in Christchurch on May 30, 2014, and smoked some before contacting a female associate to help him sell the rest.

Crown Prosecutor Andrew McRae said text evidence showed the female associate had hatched a plan to instead steal Gairns’ methamphetamine, organising Te Tomo, Desmond Kapi Marshall and another man to carry out a robbery.

On Tuesday, a Crown witness said he had seen Te Tomo chase Gairns and Marshall assault him.

Gairns then fled into the ditch, the witness said.

His body was located there the next day.

Environmental Science Research forensic toxicologist Helen Poulsen said analysis of Gairns’ blood showed a methamphetamine level of 0.7 micrograms per litre of blood.

Poulsen said this level of methamphetamine had been associated with recreational use of the drug, and levels found in the blood of people who had overdosed from using the stimulant.

In cases where death had been attributed to a methamphetamine overdose, blood levels ranged from 0.09mcg to 18mcg, she said.

‘‘The median level for these deaths is 0.96mcg, slightly higher than the level found in Gairns’’, Poulsen said.

Poulsen said Gairns’ blood also tested positive for cannabis, however the level of Tetrahydrocannabinol, the active ingredient in cannabis, in his system was not high enough to confirm its identity.

‘‘He [Gairns] is unlikely to have used cannabis shortly before his death’’, she said.

Defence Counsel James Rapley asked Poulsen if it was possible for someone to ‘‘lapse into unconsciousness’’ with a similar level of methamphetamine in their bloodstream.

‘‘I don’t know about unconsciousness, that level has been associated with causing death,’’ she said.

Forensic pathologist Catherine White said her autopsy findings were consistent with Gairns having drowned.

White said when she examined his body, Gairns had grass over his face, between his fingers and in the palm of his left hand.

White told the court watery fluid was present in his mouth, windpipe and lower airway. His lungs ‘‘oozed with copious amounts of watery fluid’’, she said.

Collections of water were present in each chest cavity, she said.

Under cross examination, Rapley asked White whether using methamphetamine could cause a cardiac arrhythmia, an irregular heartbeat. White confirmed it could. However, when asked if the post mortem showed any evidence Gairns had suffered from an arrhythmia, White said a patient needed to be ‘‘alive and have an Electrocardiogram trace’’ to track an erratic contraction.

The trial continues.