Page 154 - Libro 2

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PART 3 — PERIPHERAL ARTERIAL
AB
Figure 8-11 PPG probe placement. A: Using double-sided tape to maintain contact with the skin and (B) with a clip-style device.
THORACIC OUTLET SYNDROME
Neurovascular compression affecting the upper ex- tremity, known as thoracic outlet syndrome, is com- mon and, to some degree, can be found in up to 60% of persons without the patient necessarily developing symptoms.18 Symptoms result from compression by structures in the shoulder girdle and usually they can be reproduced with the upper extremity in a specific position or when carrying out a particular activity.
Figure 8-12 A PPG recording illustrating the use of PPG to record digital systolic pressure. The beginning of the tracing demonstrates normal pulsatile flow; pressure in an occluding cuff is increased until the pulsatile signal is obliterated; pres- sure is slowly released until the pulsatile signal returns; the point at which flow resumes is the systolic pressure which, in this example, is indicated at 84 mm Hg.
The most convenient method to test for TOS is to record PPG digital waveforms with the patient warm, sitting, and with arms resting comfortably in the lap (Figs. 8-13 and 8-14). Pulses are then recorded with:
􏰂 Arms resting in the lap
􏰂 Elbows to the rear and arms almost upright,
palms to front (military position)
􏰂 Arms elevated above the head
􏰂 Arms abducted rearward
􏰂 Arms straight out to the sides (abducted) with
head ahead, and then turned fully to the left
and then to the right (Adson maneuver)
􏰂 Any other position that elicits symptoms Finally, waveforms should be recorded with arms
resting in the lap to document that pulses are pres- ent at the completion of the study. If any position causes the waveform to become flattened, maintain this position for approximately 30 seconds to estab- lish if the patient develops symptoms (the patient may require assistance to maintain the position). Remember, up to 60% of persons can demonstrate compression without necessarily developing symp- toms. For a TOS study to be reported as positive, the systolic pressures/pulse waveforms must be signif- icantly affected by the maneuvers and the patient must develop symptoms.
COLD SENSITIVITY
As mentioned, Raynaud’s disease is classified as pri- mary or secondary and a careful history can suggest one rather than the other. Secondary Raynaud’s is as- sociated with symptoms involving one or more digits or the entire hand, with the symptoms or signs be- ing asymmetrical. These patients often will present