Happy gas makes a return to labour wards

PUBLISHED : Thursday, 29 August, 2013, 12:00am
UPDATED : Thursday, 29 August, 2013, 5:05am

Four public hospitals that stopped offering painkilling gas to women in labour will resume its use tomorrow, a year after claims it was affecting staff.

Nitrous oxide - commonly known as laughing or happy gas - would be reintroduced in Kwong Wah, Prince of Wales, Princess Margaret and Tuen Mun hospitals from tomorrow, the Hospital Authority said yesterday.

Officials were alerted to the problem last year when staff in the labour wards at Prince of Wales Hospital in Sha Tin complained about tiredness and headaches at work.

Hospital tests found that 42 out of 48 staff were being exposed to levels of the gas above the occupational limit of 50 parts per million of inhaled air set by the Labour Department.

One obstetrician warned the high levels could cause women to miscarry.

Yesterday, the authority said recent readings of nitrous oxide in staff had fallen within safety limits.

But it was unclear whether the staff had actually been exposed to the gas in the past year.

"The recently completed monitoring of personal exposure … gave satisfactory results which are well below the occupational exposure limit as stipulated by the Labour Department," said Dr Derrick Au Kit-sing, head of human resources at the authority.

He said consultants from the University of Science and Technology had recommended several control measures.

They included stepping up the inspection and maintenance of the anaesthetic gas waste system, improving ventilation and educating staff and patients.

"The multiple control measures have been effective in bringing down the exposure [to the gas]," Au said.

Prince of Wales stopped using the gas after it found the levels of exposure in its obstetrics and gynaecology department ranged from just above the 50ppm limit to 12 times the limit.

Experts in anaesthesiology said at the time that the use of the gas to relieve pain during labour was safe and effective for mothers and their babies.