Elder abuse accusation

The leap to wanting to sue rubs me wrong. Please don't jump to that right off the bat (plus you'll never win).

Once you're exonerated, move on. Sometimes clients and caregivers aren't a good match, that's all.

"Today I got a call to leave my clients. Yesterday she called the ambulance saying she cannot breathe. 

Who called you? Do you work for an agency? Or was it a relative of the clients? Why does her calling the ambulance have anything to do with you? Where you on duty? What are the grounds of abuse?

I think you need to get more information, and provide it here as well.   Who is "she"?  You write that you have "clients."   Was it the one under care who called, or a relative, or friend?

Were you present when the person in care experienced difficulty breathing?  Was she using oxygen,  if she was supposed to?  What exactly happened, if you were in fact there when the incident occurred.    And were you there when she called 911, and when the paramedics arrived?   Did she make any comments to them that addressed your care?

I am also somewhat appalled at already considering suing for distress.   Notwithstanding the inference of a relationship becoming hostile, to sue for emotional distress requires documentation of the distress by a qualified professional, as well as how that distress affected you, your ability to work, etc. 

You'd need to get a qualified mental health professional to support your claim of emotional distress, and frankly, unless the evidence and your distress is patently existent, and has caused you harm, it's not an easy claim to prove.

I do understand that you're concerned this may affect your future job options.  That's a legitimate concern.   Are police or APS investigating you?    Go over everything that happened and prepare your own summary so you can ensure that you provide responses that address your situation.

Let them investigate. It will be easy to prove that there was no abuse.

You seriously want to sue a senior that you caregive for? For emotional distress?

I'm a bit shocked that you are even asking this. Old people get paranoid, have delusions, hallucinations, can't articulate their thoughts well and a whole host of other things that a mandated reporter would feel they needed to document, so you are probably in the wrong line of work if an accusation causes emotional distress.

Time to find a new job because you can't caregive for someone feeling the way you do about this client.

Your history without complaint speaks well of you. I am uncertain what her calling an ambulance because she could not breathe has to do with this case, but apparently she lodged some sort of complaint in the ER? Was she confused, do you know? Sometimes a lack of oxygen to the brain causes confusion, and these days any ER admission of anyone it is part of "intake" to ask if anyone is abusing you. So there may have been some confusion.
I would do nothing. How did you find out you are being investigated?
If you are being investigated someone will show up to question you. Welcome them in and tell them you are frightened and appalled that this has happened, that you have done home care for 8 years and have never experienced such a thing. Ask them if the person lodging a complaint against you has been deemed to be competent, as you understood that your client was taken to hospital complaining of inability to breathe and you are aware that this can cause oxygen deprivation and possible confusion.
You might offer also to take a lie detector test, or once you know the accusation you may consider hiring someone to do your own for you.
The awful thing here is that seniors are occ. taken advantage of due to their fragility. But may also be prone to make false accusations. I saw this first hand with my beloved brother who became quite paranoid at one point about money and feeling people were watching so as to take his. And saw it often as a nurse.
I understand you must be quite terrified. Do you work for an agency or on your own? I would just tell you to be open and to answer questions until you find out the accusations. If they are very bad I would consider hiring a defense attorney to accompany you when questioned. Often this is the end of questions, in such cases, where there is no real case.
Sorry this is happening to you.