Dyspnea: A variable symptom

On my rural placement I encountered a number of respiratory patients with varying levels of dyspnea and hypoxia/desaturation. It is well known that dyspnea is not necessarily related to saturation levels, but it was interesting to see such differences between patient’s symptoms, functional levels and saturation levels.

I am going to compare three patients, and propose reasons for each of their individual dyspnea levels. The first patient is relatively young (50s) and had COPD, and was in hospital with an infective acute exacerbation. Normally the patient is independent (I) with al his ADLs and self care, and has an unlimited exercise tolerance. This patient desaturated to 82%-86% on RA after ~ 50m of ambulation, and his Borg SOB scale score 8/10. The second patient was in their late 60s, also had COPD, and was in with a non infective exacerbation. Normally this patient was I with all ADLs and self care, and was able to ambulate around the shopping centre without rests (aprox 20min). This patient desaturated to 72% on RA after ~10m of ambulation and had a Borg scale score of 0-1/10. The third patient was also in their late 60s, had COPD and was recently diagnosed with late stage lung cancer. They were on home 3-4L O2 via NP, normally I with ADLs and self care, and ambulated indoors and outdoor with a 4WW, her exercise tolerance was ~5min before needing to sit down and have a rest, due to SOB. This patient desaturated to 64% on 4L O2 via NP after ~5m ambulation. Their Borg scale score was 10/10.

The first patients acute SOBOE was most likely a result of a perfusion limitation, on top of already increased WOB (¯ complience of lungs due to their COPD). Normally the patient manages well, but they now have a V/Q mismatch due to the secretions from the chest infection blocking his bronchioles, and his WOB has now increased more then his ventilatory muscles are able to cope with. The second patients drop in saturations were most likely a result of her COPD progressing i.e. more lung tissue damage and also damage to the pulmonary capillaries. The patient did not experience an increase in SOB with the drop in their saturations, most likely due to a good level of physical function as well as seeming to have a relaxed and positive attitude which would influence the patients subjective experience of dyspnea. The third patient had a cancerous tumour nearly blocking off her left main bronchus. This would produce a substantial amount of airway resistance, which requires increased respiratory muscle WOB, plus her already increased WOB due to her end stage COPD.

It is important to know the cause of a patient’s desaturation, and possible contributing pathophysiological basis off their dyspnea, as this will direct whether physio treatment is required. Knowing the possible cause of the SOB will also guide whether the patient requires long term education about pacing themselves, ways to manage any anxiety related to the SOB, and positions of ease and potentially pulmonary rehab. The first patient was treated with ACBTs + percs + vibes+ shakes to clear secretions which helped to normalise his saturations and his SOB resolved. The second patient was prescribed domiciliary O2 and PT Rx was not indicated, the third required surgery to remove the tumour, and PT aimed to monitor her saturations, exercise tolerance and educate the patient about positions of ease and pacing her activities.