“The doctors have gone with him. But he wasn’t great on the sideline and, I’m told that he was responsive and was improving before he actually went to the hospital.
“We got two very experienced doctors there. They’ve done the usual HIA. He’s passed all that well.
“My job’s not to question doctors. They’re both comfortable with that and comfortable with him coming back onto the field.
“I don’t think there’s anything to worry about there in terms of the process. Unfortunately, I think he’s copped a second hit that’s quite heavy and there’s been a bit of a poor result on the back of that.”
Katoa copped three head knocks during the afternoon, the first coming in the warm-up when he was on the wrong end of an accidental but nasty looking hit from teammate Lehi Hopoate as the two contested a ball, but was passed fit to play.
Katoa than copped an accidental elbow from a teammate in the 10th minute and came off for a HIA but passed that and returned to the game.
In the second half, his day was officially done when he got caught in an awkward position trying to make a tackle and came off second best.
He had been off the field for five minutes, when he started feeling unwell, according to Tongan staff.
In total, Katoa played 41 minutes, where he made 59m off five carries along with 16 tackles, but he had six misses.
The incident capped off a tough night for Tonga, as they were outclassed by the Kiwis in front of 38,000 fans in Auckland.
The Kiwis outscored Tonga seven tries to two, with Dylan Brown claiming a brace and assisting two more.
The Kiwis will face Samoa in the Pacific Cup final next Sunday in Sydney.
Ben Francis is an Auckland-based reporter for the New Zealand Herald who covers breaking sports news.