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Technologies of Time |

The Technologies of Time Measurement: Implications at the Bedside and the Bench

Stanley Joel Reiser, MD, MPA, PhD
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From The University of Texas-Houston Health Science Center, Houston, Texas.

Requests for Reprints: Stanley J. Reiser, MD, MPA, PhD, The University of Texas-Houston Health Science Center, Box 20708, Houston, TX 77225; e-mail, sreiser@heart.med.uth.tmc.edu. For reprint orders in quantities exceeding 100, please contact the Reprints Coordinator; phone, 215-351-2657; e-mail, reprints@mail.acponline.org.

Ann Intern Med. 2000;132(1):31-36. doi:10.7326/0003-4819-132-1-200001040-00006
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It is remarkable how central time has been in key technologies developed to evaluate illness. Time-centered technologies can be divided into two basic categories: those that generate the data used by physicians to diagnose and follow illness and those that organize data into formats that reveal their essential medical messages. This essay examines how such technologies have emerged and influenced clinical and laboratory practice.

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Grahic Jump Location
Figure 1.
A clinical chart from the late 19th century.top linemiddle linebottom line(6)

This chart presents a visual and chronological portrait of a clinical case report. The patient's illness is tracked over 57 days. Written at the top of the chart are basic facts about the patient's age, occupation, country of residence, onset of illness, hospital admission date, diagnosis, therapy, and the numbered thermometer assigned for her monitoring. (The inconsistency of thermometers of this time, from instrument to instrument, made it desirable to track the illness of a particular patient with a particular thermometer.) Timelines showing the patient's physiologic responses to the illness and therapy are created through graphs of body temperature ( ), pulse ( ), and respiration ( ). The therapies administered—baths, ice packs, and digitoxin—are noted on the timeline, as are the patient's reactions to the therapy (she refuses baths on day 17, asks for them on day 20, and objects again on day 22). This clinical chart demonstrates the ability of the time-series graph to structure information so that comparative and predictive judgments can be made from it and to give to the viewer a readily comprehensible and evolutionary picture of an event. Reprinted from Wunderlich .

Grahic Jump Location
Grahic Jump Location
Figure 2.
Graphing the contractions of the heart.(21)

To portray the movements of a frog's heart in response to various stimuli, the detached organ is placed on a small stage. A lightweight, bullet-shaped rod set on top of the heart transmits its motions to a long lever, which makes inscriptions on a rotating cylinder. When the cylinder has completed a revolution and produced a tracing, the cylinder is lowered and a second tracing is generated below it, then a third, and so forth. Comparative measurements of the amplitude and duration of the pulsations portrayed in the tracings are made to determine the influence of the experimental interventions on the heart. Reprinted from Marey .

Grahic Jump Location




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