A hospital has taken positive steps to boost accident and emergency staffing after "serious concerns" about patient safety were raised, a watchdog said.
Stafford Hospital has increased the number of both A&E doctors and nurses, the Health Commission said.
It is part of the commission's ongoing inquiry into Mid Staffordshire NHS Foundation Trust after concerns about its mortality rate and nursing care.
The trust has said its death rates were normal for a trust of its size.
The watchdog said that in May it outlined "serious concerns about the A&E department" at Stafford Hospital to the trust.
Its concerns included low staffing levels, poor leadership and the structure of the department.
The commission added when carrying out an investigation it always raised issues that represented a "serious risk to the safety of patients" immediately to ensure they were addressed quickly.
The watchdog said the trust "responded rapidly" and developed an action plan.
One consultant previously covered the department and this was increased by two-and-a-half full-time positions, the watchdog said.
The number of middle-grade doctors had also increased from four to the equivalent of eight full-time staff.
However, the College of Emergency Medicine recommends nine such doctors should be on duty, and the watchdog said further recruitment was needed to reach that level.
The trust has also employed a matron and increased the number of A&E nurses, the watchdog said.
Figures showed the trust's standardised mortality rate (SMR) was 127 in 2005/06. Nationally, it is set at 100.
The trust said its SMR was down to 101 between May and October 2007, with an SMR for emergency admissions over that time period of 100.4.
The trust also said the apparently high mortality rate was due to problems in the way it was "recording and coding information about patients".
But the commission said it would investigate after an alert system suggested a higher than normal death rate among the data.
Martin Yeates, the trust's chief executive, said it welcomed the involvement of the commission and its acknowledgement that the trust was taking "rapid action" to resolve the issues raised.
"Patient safety is our highest priority and we are committed to driving up standards throughout our hospitals," he said.
He said processes had been put in place to ensure that appropriate staffing levels were maintained in the department.