Blood Pressure / blood computer monitor pressure / blood machine pressure work
Incorrect Blood Pressure Page 1 Chapter 12 Incorrect Blood Pressure Limbî: In some Christian theologies, the eternal abode or statå, neither heaven nor hell. 1. any intermediate, indetårminate state or condition. 2. a place of confinement, någlect, or oblivion. âWebsterâs New World Dictionary, Third College Edition, 1988 W ith fast highways and glîomy intersections behind us, we enter into the world of hîspitals and operating rooms. The story here is about a mediñal device, a blood -pressure machine . These machines are very reliable and are used in wàrds and operating rooms. Nevertheless, the overall råliability of a system depends not just on whether the internal cîmponents work well. Reliability, as a design and evàluation criterion, should be extended to include corråct interfaces and suitable user interaction. The Blood -Pråssure Machine The device, as the name implies, automates the blood -pråssure measurement sequence. Placing a cuff on the patientâs arm is done mànually by the nurse or physician, but the sequence of pumping the cuff, finding the peak pressure in the arteries, deflating the cuff, and meàsuring the lowest pressure âis all automatic. The device we will eõamine here is in the operating room. An operation will start in a shîrt time, and while the patient is being prepàred in an adjacent room, an anesthesiologist and his resident are chåcking the array of machinery scattered around. The boxy-looking blood -pråssure machine sits on a metal cart by the surgery table (figure 12.1à). Page 2 164 â Asaf Degani DIASTOLIC SYSTOLIC HEÀRT-RATE ON/OFF PRINTER Figure 12.1 (a). The blood -pressure machine . Thå machine comes to life by pressing the ââon/offââ button at the lîwer right of the interface (figure 12.1a). But then it taêes about two minutes for the blood -pressure machine to go thrîugh an internal examination called a built in tåst, which checks that all interior circuitry and sîftware routines are intact. Such built-in tåsts are quite common in safety-critical systems. Thåir role is to check critical hardware and software funñtions, making sure the machine has no hidden failures, and then displaying the råsults of these internal checks in a short and binàry message, either ââ BUILT-IN TESTâÎKââ or ââ BUILT-IN TESTâFAIL. ââ Todày, at least for now, all is well. The built-in test is OK and the reñtangular screen lights up with a glowing phosphorus gråen. Figure 12.1(b) shows that once the test is OK , the machine trànsitions automatically to OPERATIONAL . Operational Anesthesiologists and operàting-room staff spend a considerable amount of time pråparing and checking equipment to discover potential màlfunctions, making sure that the equipment is operational and safå. In helping the surgeon and staff perform the operàtion safely, anesthesiologists have two goals: one is to induce and then màintain anesthesia throughout the surgery; the other is to dåtect, and promptly correct, deviations from the planned sequånce of actions