Biomedical subjects

Kenneth Davis

Publications and source records attributed to Kenneth Davis.

3 recordsLinked to original sources

PubMed2003

Influence of low tidal volumes on gas exchange in acute respiratory distress syndrome and the role of recruitment maneuvers.

UNLABELLED: BACKGROUND Use of a low tidal volume (V(T)) strategy in the treatment of acute respiratory distress syndrome can lead to a decrease in oxygenation. This study evaluated the safety and efficacy of a recruitment maneuver (RM) in this setting. METHODS: Twelve patients with acute respiratory distress syndrome were studied within 48 hours of diagnosis. Baseline gas exchange, hemodynamics, and respiratory mechanics were determined and patients were placed on a V(T) of 6 mL/kg. Measurements were repeated and an RM of 30 cm H20 for 40 seconds was performed. Measurements were repeated at 30 minutes and 2 hours post-RM. RESULTS: Decreasing V(T) resulted in a decrease in arterial oxygenation (from 91 +/- 9 mm Hg to 75 +/- 9 mm Hg, p < 0.01), an increase in shunt (from 19 +/- 3.7% to 23 +/- 5%, p < 0.01), and a decrease in lung compliance (from 37 mL/cm H2O to 33 mL/cm H2O, < 0.05). At 30 minutes post-RM, oxygenation improved to 99 +/- 16 mm Hg, shunt decreased to 17 +/- 3%, and lung compliance improved to 39 mL/cm H2O (p < 0.05). Two hours later, oxygenation fell (86 +/- 12 mm Hg), shunt increased (20 +/- 3%), and compliance diminished (36 mL/cm H2O). There were no hemodynamic or barotraumatic complications. CONCLUSION: An RM transiently improves gas exchange during low V(T)ventilation. RMs are well tolerated and no hemodynamic consequences were seen.

Accidents, Traffic↗

PubMed2002

Pelvic fracture in the elderly is associated with increased mortality.

OBJECTIVE: The elderly population is currently the fastest growing sector in America. The purpose of this study was to examine the age-related outcome in patients after blunt pelvic injury. METHODS: All patients admitted with a pelvic fracture during a 5-year period were identified from the trauma registry. Data retrieval included: demographics, shock (BP < 90 mm Hg) on admission, injury severity score (ISS), abbreviated injury score (AIS) for head, chest, and abdomen, intensive care unit (ICU) length of stay (LOS), hospital LOS, and mortality. All pelvic fracture patterns were classified. Patient data were then stratified by age for comparison: young (< 55 years) and elderly (> or = 55 years). Statistical analysis was performed using the Student t test, Wilcoxon rank-sum test, multiple logistic regression analysis, and chi-square test with significance set at P <.05. RESULTS: Three hundred five patients sustained a pelvic fracture (young [n = 248, 81.3%]; elderly [n = 57, 18.7%]). The only predictor of mortality was age. The 2 groups differed by gender (elderly = 54.4% females; young = 62.5% males) but not frequency of shock, ISS, or AIS for head, chest, and abdomen. Motor vehicle collision was the most common mechanism of injury (elderly = 68.4%; young = 73.8%). Lateral compression was the most common fracture pattern in both groups (elderly = 54.4%; young = 45.6%). There was no difference in transfusion (elderly = 2.5 +/- 0.7 vs young = 2.0 +/- 0.3; ns) but the elderly group was more frequently admitted to the ICU (elderly = 61.4% vs young = 46.8%; P =.065). Significantly more of the elderly group had a diagnosis of cardiovascular disease (43.9% vs 10.1%, P <.001) and diabetes mellitus (10.5% vs 2.4%, P <.014). Mortality was significantly greater in the elderly group (12.3% vs 2.3%). CONCLUSION: Elderly patients sustaining a pelvic fracture were more likely to have a lateral compression fracture pattern, longer hospital LOS, and die despite aggressive resuscitation. This difference in outcome should help trauma surgeons recognize that the elderly patient sustaining a pelvic fracture is at increased risk of death.

Adult↗

PubMed2002

Closed-loop mechanical ventilation.

Closed-loop mechanical ventilation encompasses a plethora of techniques, ranging from the very simple to the relatively complex. In the simplest form, closed-loop ventilation is the control of one output variable of the mechanical ventilator based on the measurement of an input variable. An example would be pressure support ventilation, in which flow (output) is constantly changing to maintain pressure (input) constant throughout inspiration. More complex forms of closed-loop ventilation involve measurement of multiple inputs (eg, compliance, oxygen saturation, respiratory rate) to control multiple outputs (eg, ventilator frequency, airway pressure, tidal volume). The latter type of control more closely mimics the ventilatory control and response of human physiology. This review discusses both currently available closed-loop ventilation techniques and those only available outside the United States, along with some cutting-edge techniques that have only limited use. The operation, theoretical advantages, and limitations of each technique are reviewed. When available, the literature supporting or refuting each technique will be reviewed, but, unfortunately, little has been published on certain techniques.

Algorithms↗