A doctor said he “felt extremely uncomfortable” at the thought of nurse Lucy Letby being alone with a baby girl.
Letby, 33, is said to have deliberately dislodged the infant’s breathing tube shortly before consultant Dr Ravi Jayaram walked in the nursery room.
The alleged attempted murder is said to have taken place during a night-shift at the Countess of Chester Hospital’s neonatal unit in February 2016.
The Crown say Letby struck at 3.50am, less than two hours after the extremely premature-born youngster, Child K, was born.
Giving evidence on Tuesday, Dr Jayaram said: “Jo had told me she was going to the labour ward and she told me that Lucy Letby was babysitting, keeping an eye on things.
“At this point, in mid-February, we were aware as a team of a number of unexpected and unusual events and we were aware of an association with Lucy Letby.
“That’s all we were aware of. No cause and effect had been ascribed.
“I will admit it seemed entirely irrational and illogical – Jo told me she was going and Lucy was there, I felt extremely uncomfortable.
“You can call me hysterical, you can call me irrational, but that’s how I felt because of this association.
“After two-and-a-half to three minutes, I got up to to check on (Child K) to prove to myself that I needed to stop being ridiculous and irrational, and of course everything was going to be OK.
“I had not been called to review (Child K) and I had not got up because I heard alarms going off.
“I went up to nursery one and walked in.”
Phil Astbury, prosecuting, asked: “What, if anything, did you see?”
Dr Jayaram replied: “As I walked up, I saw Lucy Letby standing by the incubator and the ventilator. She didn’t have her hands in the incubator.
“The ventilator was not alarming and the incubator was not alarming and the monitor is set to alarm when the sats drop below 90%.
“I recall saying, ‘What’s happening?’ and Lucy looked and said something along the lines of, ‘She is having a desaturation’.”
Mr Astbury asked: “What, if anything, was she doing?”
Dr Jayaram said: “Nothing.
“I wasn’t aware she was looking at the monitor… She didn’t say anything to me until I asked what was happening.”
Mr Astbury asked: “Any more conversation between the two of you?”
Dr Jayaram said: “We switched into professional mode.
“It didn’t really make sense to me why the tube became dislodged. It had been secured and (Child K) was not a vigorous baby.
“It’s very difficult to dislodge an ET (endotracheal tube) without it being spotted.
“So I then removed the tube, which was not blocked.”
Dr Jayaram said he went on to give rescue breaths to Child K and her chest began to move again and her oxygen levels went up.
Child K was transferred later that day to Wirral’s Arrowe Park Hospital, where she died three days later.
Jurors were told the Crown does not allege Letby caused her death.
Ben Myers KC, defending, has told jurors the “probable cause” of the dislodgement was the child inadvertently moving it herself.
He said to Dr Jayaram: “You told the police that it might have been done on purpose.”
Dr Jayaram said: “It was certainly one of the things that crossed my mind.”
Mr Myers said: “You had ‘got her’ then?”
The consultant replied: “No, because I had not seen her do anything.”
Mr Myers said: “So did you confront her?”
Dr Jayaram said: “Absolutely not. It’s my job to deal with the baby. It’s not my job to do that.”
Mr Myers went on: “Do we see anything in your notes relating to suspicious circumstances with a dislodged tube?”
Dr Jayaram replied: “Mr Myers, that is not the sort of thing one writes in clinical notes ”
He denied the barrister’s suggestion that he had “added detail to your account as you go along”.
Mr Myers put it to Dr Jayaram that he was “very anxious” to tell the police that Child K had been sedated at the time and therefore could not have dislodged the tube.
Dr Jayaram conceded that medical notes appeared to show she was not receiving morphine when he walked into the room.
Mr Myers said: “You added that detail to support the impression you wanted to create that someone interfered with that tube?”
Dr Jayaram said: “No, in good faith I thought that she was on a morphine infusion at that time.”
Mr Myers said: “Some of the management of her care on your watch fell below the standard that she required, didn’t it?”
The consultant replied: “I disagree. There were things that we could absolutely do better in terms of intubation but I disagree entirely that the care she got was detrimental.”
Mr Myers asked: “Have you sought to distract from shortcomings in your care, at least in part, by creating this issue with Lucy Letby about this incident?
Dr Jayaram said: “Absolutely not.”
Mr Myers said: “Are you seeking to bolster suspicion about Lucy Letby by adding details after the event?”
“Absolutely not,” repeated the consultant.
Letby, originally from Hereford, denies murdering seven babies and trying to kill 10 others between June 2015 and June 2016.
The trial continues on Wednesday.