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Patients with serious illness or
injury or life-threatening states invariably require close observation
to detect changes in function or state. Electronic monitoring complements
the information gathered from direct physical examination by providing
(1) repetitive or continuous assessment that does not disturb the
patient, (2) a means for detecting the effect of interventions,
and (3) warning signals for physiological disturbances that permit
staff to observe multiple patients simultaneously. Current monitoring
devices also frequently have the capacity to store data that can
be reviewed subsequently for analysis. Because of the vital importance
of circulatory and respiratory function, much of the monitoring
in common use tracks activity of these systems, and such monitoring
is the focus of this section.
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Monitoring of respiratory rate provides valuable clues about
disturbances in respiratory function (see Chapter 102). Processes that decrease respiratory system compliance
often cause the respiratory rate to increase; processes that depress
ventilatory drive cause the respiratory rate to decrease. Such monitoring may
be useful both in hospitalized patients and in those at home who
are at risk for breathing disturbances. Respiratory rate is assessed by
devices that monitor breathing movement, gas flow, or gas exchange.
Each approach is described briefly in the following sections and is
shown in Figure 106-1 and in the Table 106-1.
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