Page 156 - Libro 2

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PART 3 — PERIPHERAL ARTERIAL
this instance, the hands will change color when ex- posed to cold. The progression of this color change is white, changing to blue, and then red when the hands are warmed. These symptoms can occur con- sistently when picking up a cold item, such as a glass of ice water, but are also seen when the en- tire body is slightly cooled, such as with seasonal changes in outside temperature. In this situation, the cool mornings in the spring or fall result in the wearing of lighter clothing, and the vasospastic re- sponse triggers the autonomic sympathetic system to constrict. This is an overreaction in those with primary Raynaud’s, resulting in the color changes. This reaction can be reduced by dressing warmer than usual.
Testing for primary Raynaud’s can be accom- plished using waveform analysis of the digital trac- ings and/or a digital temperature monitoring device (Fig. 8-15). The digital pulse should be taken prior to immersion in ice water, and it may appear normal or may exhibit a “peaked pulse” on the anacrotic (systolic) portion (Fig. 8-16) that is frequently seen in primary Raynaud’s.19 There are several stress level meters or biofeedback monitors available, which are accurate to 􏰀0.1°C and are not expensive (usually less than $30). Prior to beginning the testing and challenge by immersion into ice water, the hands should be warmed to a minimum of 28°C (82°F). Immerse the hands in warm (not hot) water for sev- eral minutes, until they feel warm to the touch. In addition, the testing room should be comfortably warm at 23° to 24°C (74° to 76°F), so the patient is not cooled by the environment.
For this exam, the patient sits comfortably in a chair (one having a back will facilitate this) with a towel placed over the lap. This will avoid water
Figure 8-15 A digital temperature monitoring device used for Raynaud’s testing.
AB
Figure 8-16 Digital PPG waveforms. A: A normal waveform. B: A “peaked pulse” waveform frequently seen in primary Raynaud’s.
getting on the patient when the hands are removed from the water.
A “resting” digital pulse is then recorded from both hands and digital blood pressures are measured, if indicated, or a component of individual protocols. The PPG should be secured to the wrist to avoid “pulling” of the probe away from the digit. Securing the probe to the digit with double-stick tape (see Fig. 8-11A) will provide a clean tracing. If a thermometer is used, again the sensing probe should be secured to the digit with a Velcro strap and secured at the wrist as with the PPG probe.
It is helpful to place the hands in large disposable latex gloves (if there is no latex allergy) and secure the glove at the wrist with a strip of tape (Fig. 8-17). This will prevent the hands from getting wet and will allevi- ate the need to dry the hands when removed from the ice water. The hands should be immersed into the ice water, to just below the top of the gloves (Fig. 8-18).
Figure 8-17 The use of disposable gloves to protect PPG sensors used during cold sensitivity testing.