Scotland's largest health board has overhauled its policy around the administration of intravenous drugs following a critical report which it ordered in response to a spike in hospital superbugs cases.

NHS Greater Glasgow and Clyde commissioned the audit into its use of central venous catheters and peripheral venous catheters, which give doctors direct access to a patient's bloodstream, after an increase in the numbers of Staphylococcus aureus bacteraemia cases, better known as MRSA or MSSA, in the latter half of last year. The catheters, which are commonly used in hospitals, also present an infection risk.

The PricewaterhouseCoopers (PwC) team that carried out the confidential audit, the results of which have been released through Freedom of Information laws, made six findings, including two that were classified as "high risk" and two "medium risk".

It revealed confusion in the use of the basic apparatus across the health board. There was no approved policy for the insertion and maintenance of the catheters, which are also used to draw blood and administer fluids, increasing risk of inconsistent approaches across the board and leading to uncertainty among staff. The auditors warned: "PVCs and CVCs can be a source of infection, and the rate of infection is increased where catheter insertion and maintenance procedures are not being properly managed."

Dr Jean Turner, director of the Scotland Patients Association, said it was vital that a rigid protocol was followed at all times.

"Everybody needs to know that when they put a needle and cannula into a vein it does create a hazard," she said. "This is an important area and it is obvious that what has been going on has been a bit haphazard.

"I hope they are going to be able to implement a standard method. It should be standardised throughout Scotland. Everybody should be sticking to the same protocols religiously."

The investigation also revealed that while care plans had been introduced for patients with peripheral venous catheters, which are typically inserted into a patient's hand or arm, they were only used for central venous catheters, usually inserted into a patient's neck, in one department.The PwC team said that staff should complete a care plan form in all cases, or else rules may not be followed and bosses could receive inaccurate data on whether protocol was being followed.

Concern was also raised that too many departments were involved with management and monitoring of processes around catheters, increasing the risk of inconsistency, and that different teams used different criteria when investigating whether the equipment was being used appropriately.

Following the audit, carried out in January, NHS Greater Glasgow and Clyde tightened up its policy. Statistics produced by Health Protection Scotland show that rates of MRSA and MSSA, which have decreased in the last decade, rose in the two successive quarters in the latter half of 2013. But figures from the first quarter of this year indicate the trend has reversed with the board on course to hit national targets.

A NHSGGC spokeswoman said: "We have developed standard operating procedures for the insertion and maintenance of both peripheral vascular cannula and central venous cannula. These have been widely consulted on with front line clinical teams before being presented to NHSGGC's Infection Control Committee where they received approval on May 19, 2014.

"The care plan for Peripheral Vascular Cannula (PVC) has been updated to reflect current evidence based practice and the care bundles issued nationally. A Central Venous Cannula (CVC) care plan has also been developed in the same way."