Covid-19 is proving to be a many-headed monster. And though most people will steadily improve and recover, a small percentage (up 4%) suffer a precipitous, unpredicted and sometimes delayed decline. Experts are warning that waiting for the “classic” symptoms – difficulty in breathing and high fever – may mean that some cases of pneumonia and other complications may be missed. But how do you know whether you’re the one who will need hospitalisation? Will you end up in ICU? How do you know when you’re out of the woods? And are there any specific ways of assessing whether you’re getting better or worse?
Most of us can put up with the sweats, aches, cough and deep fatigue for a few days if we know that we’ll turn the corner and begin a couple of weeks of gradual recovery. Michael, a 27-year-old coronavirus patient, told me: “At first, it was like wading through a sea of treacle just to reach the loo. I felt like a small child was sitting on my chest so that breathing was really hard work. Then after a couple of days, my breathing eased and I could potter around my flat like my grandmother does, though a bit slower. The thought of going out for a 5K run, which I used to do in about 24 minutes, still feels impossible. But I’m in my third week and I can feel that I’m on the mend. I wish that someone had told me that it would take this long because not knowing is really scary.”
As Michael’s GP, I would have been the obvious person to advise him on what to expect. But the truth is that the presentations, complications and consequences of this novel virus are still unfolding; the initial phone triage pathway that doctors like me were advised to follow at the start of the crisis was pragmatic and generally safe but didn’t cover the myriad exceptions to the rule that have since become apparent.
One concern is that pneumonia can develop, which only causes symptoms of shortness of breath once it is at an advanced stage. Pneumonia occurs when the tiny air sacs in the lungs (alveoli) become inflamed by a virus, bacteria, fungus or irritant particle and fill with fluid or pus, making it hard to breathe. Too little oxygen in the lungs means that the blood can’t pick up enough to carry to every organ and cell in the body (resulting in a condition called hypoxia). Sustained hypoxia causes organ failure and cell death. Administering oxygen via a mask or CPAP machine can help at first but if the alveoli are too bunged up then no amount of oxygen will help and mechanical breathing assistance (ventilation) becomes necessary.
It can be hard to know when a chest infection that affects bigger airways but leaves the alveoli able to function is developing into a potentially dangerous pneumonia. Pointers are a temperature over 37.8C, a pulse rate over 100 beats per minute, crackling sounds heard through a stethoscope and oxygen saturation levels in the blood lower than 95%. A chest X-ray or CT scan may also show abnormalities that point to pneumonia. But none of these is entirely reliable on its own; for example, your pulse rate may be high if you’re unfit, anxious, have just consumed caffeine or have a fever from any cause.
Oxygen saturation levels are a measure of how much oxygen is getting round your body and can be fairly reliably assessed with a little gadget called a pulse oximeter that clips on to your finger. Two wavelengths of lights are emitted by an LED inside the device on one side of the finger. The light that passes through the fingertip is measured and the amount that has been absorbed by the oxygen in the blood is calculated to give an oxygen saturation – or “sats” – reading. A figure is displayed, which is the percentage of the maximum amount of oxygen that the blood should carry, and the ingenious little gadget – which runs on one AAA battery – also displays heart rate.
Pulse oximetry is a useful adjunct in deciding who needs treatment, admission to hospital, oxygen therapy, a transfer to intensive care, ventilation and then, at the other end of the tunnel, who can be safely discharged home and reassured that they’re on the mend. Oximeters don’t work well if your hands are cold, you have shellac on your nails or the battery is flat.
Anyone who is too breathless to complete a sentence, has severe chest pain, is drowsy, confused or unable to stand up due to dizziness will need urgent assessment, usually with a 999 call. Relying on a sats measurement isn’t safe if you’re clearly seriously unwell and deteriorating. But in a more borderline call, a sats reading of over 96%, a heart rate under 90 beats per minute and a respiratory rate of under 20 breaths per minute are reassuring.
GP surgeries have been given pulse oximeters to lend to patients at home to monitor their progress either as the infection is developing or as recovery kicks in. We’ve only got two for 5,000 patients and had a bit of difficulty getting one of them back from a patient who understandably wanted to hang on to it. You can buy them online or from some pharmacies (costing £20-60) and there are a lot of Chinese-made ones on eBay.
But the real message isn’t to rush out to bag a pulse oximeter at all costs. The message is that this Hydra of a virus can present in insidious ways, especially in the frail and elderly. If you are feeling increasingly ill, confused or drowsy, don’t wait until you can’t breathe or until the pulse oximeter arrives. Get help: call 111 or your GP as a first step if you can, and 999 if it feels like you can’t wait.
Ann Robinson is a GP
