Critical care medicine
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Critical care medicine · Jun 1990
Predictive equation for assessing energy expenditure in mechanically ventilated critically ill patients.
Traditional formulas, such as the Harris and Benedict equation (HBE), do not accurately predict energy expenditure (EE) in mechanically ventilated, critically ill patients (MVCIP). The purpose of this study was to develop a predictive EE equation to assess EE requirements in MVCIP. A portable metabolic cart was used to measure indirectly EE in 112 MVCIP. ⋯ The HBE underestimated measured EE by 34 +/- 19% and in 79 patients deviated greater than 15%. Using the new equation, only 15 patients' EE deviated greater than 15% from measured EE. The new predictive EE equation can accurately assess EE in MVCIP.
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Critical care medicine · Jun 1990
Trending of impedance-monitored cardiac variables: method and statistical power analysis of 100 control studies in a pediatric intensive care unit.
The NCCOM3-R6 monitor continuously monitors cardiac output and five other cardiovascular variables from the thoracic electrical bioimpedance signal. We averaged data over 5-min intervals for 130 min in 100 control studies in 40 pediatric ICU patients, age 0.04 to 20.39 yr (median 1.39) and weighing 2.0 to 59.5 kg (median 8.8). For individual studies, 99% of the 5-min averages of cardiac output fell within +/- 44% of the baseline cardiac output for that study. ⋯ When we averaged data for 100 studies, 5-min interval observations for each variable did not deviate from baseline over a 2-h period (p greater than .70). With a sample size of 100 studies, we could detect a change in cardiac output of +/- 5% at the p less than .005 level with a power of 0.95. We conclude that with a sufficiently large sample size, studies employing the NCCOM3 can detect clinically significant cardiovascular changes due to pharmacologic or procedural stressors.
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A retrospective review of 99 consecutive patients with flail chest after trauma was conducted to determine the incidence and significance of delayed presentation. Patients ranged in age from 7 to 88 yr (mean 50.3). Hospitalization ranged from 1 to 129 days (mean 23). ⋯ Delayed presentation occurred in 22 (22%) patients from 1 to 10 days after injury. Reasons for delayed diagnosis included intubation and mechanical ventilation before complete physical examination, development of pulmonary complications with the attendant increased work of breathing, and physician error. The time of presentation was not associated with patient age, sex, severity of injury, need for mechanical ventilation, duration of ventilation, incidence of pulmonary morbidity, or mortality.