What makes you say that this pt is septic? What two lines? How would you admin the O2? Why would you consider intubation? If the SPO2 didn't improve and when would you make that decision? I'm asking not to offend, but to learn from others in the field.
I kind of covered a couple of these in my post above, must have been at the same time as you were posting.
This pt has severe sepsis because he is:
Febrile (temp >38 celsius)
Tachycardic (rate >90)
Tachypneic (rate >20)
(and I would presume he will have white cell abnormalities)
He also has hypotension.
So clinically, he fits the criteria for SIRS, and as he is in a nursing home he has a good chance of having a respiratory focus (and the rales of course point to that as well)
Need good, large bore IV access because first and foremost this patient needs aggressive fluid resuscitation. Sepsis causes a number of problems (well, craploads actually, it's an incredibly complex beast) and leaky capillaries is a major one. These patients lose and enormous amount of fluid from their capillaries, and the also tend to make enormous quantities of poor quality urine. Added to this the fact that they will have likely had poor oral intake, possibly for some days, and you end up with a really crappily perfused, dry as hell patient. These patients need multiple litres of fluid. Many multiple litres.
This will be one of the few times that I give high concentration of O2. Even if he had a relatively normal SpO2, I would still give O2, because septic patients have an enormously increased O2 demand at a tissue level. This is why SCVO2 is measured to get an idea of perfusion (although there is some doubt about how useful it is)
Intubation is probably indicated (or is indicated, it's whether we do it there or at hospital that is the question) to maximise O2 delivery with high FiO2 if needed and to add some PEEP to ensure recruitment of alveoli (someone smarter than I am needs to explain that better, or correct me if I'm wrong)
It will also help relieve some of the workload, this patient is breathing up hard, burning a lot of energy with thei respiratory muscles, adding to the lactate production and sucking up O2. Once tubed, head up 30degrees, careful suctioning of tube and oropharynx, try not to add more bugs to the stew.
I forgot to mention the mineralcorticoids if/when vasporessin is started. If we get to that point it suggests a relative adrenal insufficiency so steroids are indicated. 100mg for a start, repeated 8 hourly (not that I'll have him for that long)