Visual display format affects the ability of anesthesiologists to detect acute physiologic changes. A laboratory study employing a clinical display simulator.

BACKGROUND: Anesthesiologists use data presented on visual displays to monitor patients' physiologic status. Although studies in nonmedical fields have suggested differential effects on performance among display formats, few studies have examined the effect of display format on anesthesiologist monitoring performance. METHODS: A computer-based clinical display simulator was developed to evaluate the efficacy of three currently used display formats (numeric, histogram, or polygon displays) in a partial-task laboratory simulation. The subjects' task consisted solely of detecting any changes in the values of the physiologic variables depicted on a simulated clinical display. Response latency and accuracy were used as measures of performance. RESULTS: Thirteen anesthesia residents and five nonmedical volunteers, were enrolled as subjects. Use of either the histogram or polygon displays significantly improved response latencies and allowed greater accuracy compared with the numeric display in the anesthesia residents. Neither response latency nor accuracy improved with additional exposure to these displays. In contrast, display format did not significantly affect response latency or accuracy in the nonmedical volunteers. CONCLUSIONS: The results of this study suggest that graphic displays may enhance the detection of acute changes in patient physiologic status during anesthesia administration. This research also demonstrates the importance of assessing performance on clinical devices by studying actual users rather than random subjects. Further research is required to elucidate the display elements and characteristics that best support different aspects of the anesthesiologist's monitoring tasks.

Changes in fitness and shipboard task performance following circuit weight training programs featuring continuous or interval running.

Pre- and post-physiological data were collected on 57 Navy men (mean age = 19.5 years) who participated in either circuit weight training/continuous run (CWT/CR) (N = 31) or circuit weight training/interval run (CWT/IR) (N = 26) programs. Measured variables included 4 measures of upper torso dynamic strength (one repetition maximum [1 RM] for arm curl, bench press, shoulder press, and lat pull-down); two measures of lower torso dynamic strength (1 RM) for knee extension and leg press); one measure of power (number of revolutions completed on an arm ergometer (Monark) at maximum drag); three measures of muscular endurance (number of repetitions at 60% 1 RM for bench press and leg press and maximal number of bent-knee sit-ups in 120 s); one stamina measure (time to exhaustion on a cycle ergometer (Monark) maximal work capacity [MWC] test; and three simulated shipboard tasks: manikin shoulder drag, open/secure a water tight door and paint bucket carry. Composite shipboard performance derived from the summed time (s) required to complete the three tasks was also calculated. Results show performance on the manikin shoulder drag and majority of evaluative fitness measures was significantly (p less than 0.05) enhanced following both circuit weight training/run formats. Significantly (p less than 0.05) higher values for shoulder press (F = 7.2), arm ergometer (F = 5.3), and sit-ups (F = 6.8) and lower values for leg press muscular endurance (F = 5.1) were observed in CWT/IR when compared to CWT/CR.(ABSTRACT TRUNCATED AT 250 WORDS)

Decrements in logical reasoning performance under conditions of sleep loss and physical exercise: the factor of sentence complexity.

Baddeley's Logical Reasoning Test was used in a series of Sustained Operations (SUSOP) studies involving 100 US Marine Corps enlisted subjects, to assess the effects of sleep loss and long-term physical exercise on the ability to process complex information. The percent correct answers to the eight Logical Reasoning sentence types involving different voice (active vs passive), use of negatives, and outcome (true vs false) were analyzed over three days across three levels of exercise and rest conditions in the seven studies. A multivariate analysis of variance indicated no differences on the baseline day among the seven studies. Analyses on the baseline day and throughout the next two continuous workdays (CWs) showed consistently higher percent correct for the actively worded than for the passively worded sentences. The sleep loss over the two CWs resulted in a significant decrease in percent correct for the statements which had active wording. Sleep loss had no effect on statements with passive wording. There were no differences in comprehension between groups which had different rest conditions (no rest, 3- or 4-hr. nap, 8-hr. sleep) between the two CWs for any of the sentences; and there was no recovery from prerest to postrest. Fatigue due to exercise during either CW had no effect on comprehension for any of the sentence types. The sleep loss effects on comprehension seem due to a lessening of the attention given to those more simple sentences in active voice, whereas increased arousal may have been elicited by the more complex sentences in passive voice. The increased attention to the passive statements may have overcome the effects of sleep loss. The present study shows the usefulness of analyzing responses to the logical reasoning test by sentence complexity for indicating selective cognitive changes in the processing of information.

Altered circadian periodicities in oral temperature and mood in men on an 18-hour work/rest cycle during a nuclear submarine patrol.

A group of nuclear submariners was studied to examine whether an 18-h routine (6-h on, 12-h off watch) during a 10-week submerged patrol affected the 24-h circadian rhythm in oral temperature, Thayer's activation, Mood 'Activity' (MA) and Mood 'Happiness' (MH). They were observed during three phases of the patrol: Phase 1, the beginning 8-day period; Phase 2, the middle of the voyage; and Phase 3, the last 7-8 day period. The group-synchronized 24-h rhythm in oral temperature disappeared during Phase 3. The group-synchronized 24-h rhythms in Thayer's activation and in MA and MH disappeared during Phases 2 and 3. A group-synchronized 18-h rhythm was not produced in any of the variables in any phase, except MH during Phase 2. Periodicity analysis of the individuals' data showed that a loss of 24-h rhythmicity in oral temperature was due not only to reduced circadian amplitude but also to a dispersion of Time of Peak (TOPs). Loss of 24-h rhythm in 'Activation', 'Happiness', and 'Activity' was predominantly due to a wider dispersion of TOPs. The 18-h routine did appear to exert a small modulating effect on rhythmic activity in the variables examined in this study. Since the sleep/wakefulness cycle was well entrained by the 18-h routine, the submariners experienced a spontaneous internal desynchronization between the activity cycle and the cycles or oral temperature and psychological states. The performance and health consequences of this chronic dyschronism have yet to be explored. We suggest further research to determine the usefulness of an index of synchronization among the physiological and psychological variables, and the relationship of the desynchronizing effects to performance.

An attempted validation study of the birthdate-based biorhythm (BBB) hypothesis.

The birthdate-based biorhythm (BBB) hypothesis was examined for utility as a predictor of human performance. Data from quizzes of 26 students taken periodically throughout a semester, and measures over 1 month of landing performance by seven pilots were analyzed by multiple regression/correlation methods. Regression equations were developed to test the correspondence between performance and cycle phases. A second analysis used a nonorthogonal least-square spectrum method to determine if the data contained any systemic rhythms in the intradian range. No significant results were obtained whcih would support the BBB hypothesis as a predictor of human performance. Also, no evidence was found to substantiate the existence of the three proposed BBB cycles.