Every number looks close to normal: is she fine?

Breathing rate: when oxygen runs low or acid builds up, the brain speeds up breathing to make up for it.

Ten o'clock on a surgical ward, and Alex, a student nurse, is doing obs: short for observations, the vital signs. Mrs Smith in bed twelve had her hip replaced two days ago.

I'm fine, love, she says. Alex writes down six numbers, and each one looks close to normal. If you were Alex, would you be worried? Hold that thought.

So how did Alex get those numbers? Let's rewind and watch. Alex counts her breathing for fifteen seconds while she chats, and times it by four.

Sixteen. Sats 96 percent. Heart rate 98. Blood pressure 118 on 72. Temperature 37.8.

Alert. Close enough to normal. Done. Pause here, and count the problems. There are three.

Her breathing was counted for fifteen seconds while she talked. Each number was checked on its own. And nobody compared them with the six o'clock set.

Sam, the supervising nurse, looks at the chart and says, close to normal doesn't mean fine. The numbers tell a story. Let's read it.

Serious events, like a cardiac arrest, are often preceded by changes in the obs, sometimes up to a day before. Where you work changes the chart. Each state and territory has its own, and hospitals can adjust the triggers.

Some, like Between the Flags in New South Wales, colour each vital sign by zone. Others, like Queensland's Q-ADDS, give each vital sign points and add them up, so small changes count together.

New Zealand's national chart adds them up too. First, breathing rate. A normal adult at rest takes about 12 to 20 breaths a minute. Alex counts again for a full minute, still holding her wrist so she doesn't notice.

Twenty two. At six it was sixteen. When oxygen runs low or acid builds up, the brain speeds up breathing to make up for it.

That's why it often changes first. Second, oxygen saturation, or sats: how much oxygen the blood is carrying. Healthy adults usually sit at 95 percent or above.

Hers is 96. But the clip measures oxygen, not how hard she's working to get it. So good sats alone don't mean she's fine. Third, heart rate.

Normal is 60 to 100 beats a minute. Hers is 98, up from 82. Fever or infection can make the heart beat faster, to move more blood and oxygen around the body.

Fourth, blood pressure. 118 on 72, a little lower than at six. It can hold steady for a while, because the heart speeds up and blood vessels tighten to make up for it.

So a falling blood pressure can be a late sign. Fifth, temperature. Normal is about 36.5 to 37 degrees, and a fever is 38 or more.

Hers is 37.8, up from 37. The immune system turns up the body's thermostat to fight infection. But older people may not get a fever at all.

Sixth, consciousness. Is she alert, and making sense? She is. New confusion or drowsiness is a warning sign, because the brain needs a steady supply of oxygen and blood.

Now read them together, next to six o'clock. Breathing up. Heart rate up. Temperature up. Blood pressure drifting down.

Sats just holding. That's a body working harder to keep up. Alone, each number looks okay. Together, they tell a story. Alex tells Sam.

Her breathing is 22 over a full minute, up from 16. Heart rate and temperature are up, blood pressure is drifting down. I'm worried about her.

Sam says, so am I. And worry counts. In Australia and New Zealand, the rules for escalating, calling in more senior help, include a staff member's concern, even when the numbers look okay.

Sam tells the nurse in charge, and they agree to check her obs again sooner. At the next check, she's breathing 24, and her sats have dropped to 91 percent.

Alex picks up the phone. If you've seen our ISBAR video, you know how that call went. Your turn. Pause if you need more time.

Which vital sign often changes first? Three, two, one. Breathing rate. Her blood pressure is normal, so she's fine. True or false?

Three, two, one. False. Blood pressure can hold up until late. Every number looks close to normal, but you're worried.

What do you do? Three, two, one. Speak up. Worry is a reason to escalate on its own.

So: count breathing for a full minute, compare with the last set, read the numbers together, and say when you're worried. Think back to the start.

Would you have been worried? Alex still checks every number. But now Alex reads the story. Comment below: which vital sign do you find hardest to take?

Subscribe for next time: surviving your first week on placement. Alex, Sam and Mrs Smith are fictional. Charts and triggers vary between states and hospitals, so always follow your local policy.

This is general education only.