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Biomedical subjects

Thomas L Higgins

Publications and source records attributed to Thomas L Higgins.

6 recordsLinked to original sources

New-generation pulse oximetry in the care of critically ill patients.

OBJECTIVE: To review the published, peer-reviewed studies to date on use of the new-generation pulse oximeters, which are manufactured with algorithms to filter out patients' body motions, and describe the application of new-generation pulse oximetry in clinical practice in critical care. METHODS: MEDLINE was used to locate appropriate articles on pulse oximetry for the years 1995 to 2003. Each article was examined for scientific merit, content, and applicability to clinical practice. RESULTS: A total of 17 relevant articles on the clinical performance of the new-generation pulse oximeters were reviewed, and the data were organized into a table. CONCLUSIONS: The combination of studies done in both clinical and laboratory settings did not provide any strong and convincing evidence that the performance of any single new-generation device was superior to that of any other new-generation device. However, the clinical performance of all the new-generation pulse oximetry devices was better than that of earlier devices.

Adult↗

An exploratory study using data envelopment analysis to assess neurotrauma patients in the intensive care unit.

Patients with severe head trauma were studied retrospectively to determine if Data Envelopment Analysis (DEA) could successfully model patients early in their stay in an intensive care unit. Variables examined were cerebral perfusion pressure, body temperature, mean arterial pressure, serum osmolarity and pCO2. Unlike regression-based models that focus on mean values for the group, DEA evaluates each patient individually calculating an "efficiency" score based on a patient's ability to maximize output for a given set of physiologic inputs. Patients with high efficiency scores were found to have a better chance of making a full recovery than similarly injured patients that were inefficient. This approach needs further study but may offer physicians the opportunity to improve patient outcome subject to the manipulation of individual variables from the results of a DEA model rather than aiming for normal or average physiologic values.

Brain Injuries↗

Early indicators of prolonged intensive care unit stay: impact of illness severity, physician staffing, and pre-intensive care unit length of stay.

OBJECTIVE: Scoring systems that predict mortality do not necessarily predict prolonged length of stay or costs in the intensive care unit (ICU). Knowledge of characteristics predicting prolonged ICU stay would be helpful, particularly if some factors could be modified. Such factors might include process of care, including active involvement of full-time ICU physicians and length of hospital stay before ICU admission. DESIGN: Demographic data, clinical diagnosis at ICU admission, Simplified Acute Physiology Score, and organizational characteristics were examined by logistic regression for their effect on ICU and hospital length of stay and weighted hospital days (WHD), a proxy for high cost of care. SETTING: A total of 34 ICUs at 27 hospitals participating in Project IMPACT during 1998. PATIENTS: A total of 10,900 critically ill medical, surgical, and trauma patients qualifying for Simplified Acute Physiology Score assessment. INTERVENTIONS: None. RESULTS: Overall, 9.8% of patients had excess WHD, but the percentage varied by diagnosis. Factors predicting high WHD include Simplified Acute Physiology Score survival probability, age of 40 to 80 yrs, presence of infection or mechanical ventilation 24 hrs after admission, male sex, emergency surgery, trauma, presence of critical care fellows, and prolonged pre-ICU hospital stay. Mechanical ventilation at 24 hrs predicts high WHD across diagnostic categories, with a relative risk of between 2.4 and 12.9. Factors protecting against high WHD include do-not-resuscitate order at admission, presence of coma 24 hrs after admission, and active involvement of full-time ICU physicians. CONCLUSIONS: Patients with high WHD, and thus high costs, can be identified early. Severity of illness only partially explains high WHD. Age is less important as a predictor of high WHD than presence of infection or ventilator dependency at 24 hrs. Both long ward stays before ICU admission and lack of full-time ICU physician involvement in care increase the probability of long ICU stays. These latter two factors are potentially modifiable and deserve prospective study.

APACHE↗

Hemodynamic consequences of heart-lung interactions.

The management of critically ill patients requires a fundamental understanding of cardiopulmonary interactions associated with mechanical ventilation. The hemodynamic changes due to ventilation are a result of changes in lung volume and intrathoracic pressure (ITP) and can occur during spontaneous or positive pressure ventilation despite constant tidal volumes. Pulmonary vascular resistance (PVR) and mechanical heart-lung interactions play prominent roles in determining the hemodynamic response to mechanical ventilation. Lung inflation alters PVR and right ventricular wall tension and, at high lung volume, mechanically limits cardiac volumes. The authors will consider the mechanisms of the effects of ITP on the pulmonary arterial and venous branches. These effects will aid in understanding the complex interactions between ventilation and right and left ventricular pressures and volumes, as well as the influence of lung inflation pressure on ventricular interdependence.

Cardiac Volume↗