Biomedical subjects

Linda Khaw

Publications and source records attributed to Linda Khaw.

4 recordsLinked to original sources

PubMed2006

Continuous muscle tissue oxygenation in critically injured patients: a prospective observational study.

BACKGROUND: Despite normalization of vital signs, critically injured patients may remain in a state of occult underresuscitation that sets the stage for sepsis, organ failure, and death. A continuous, sensitive, and accurate measure of resuscitation after injury remains elusive. METHODS: In this pilot study, we evaluated the ability of two continuous measures of peripheral tissue oxygenation in their ability to detect hypoperfusion: the Licox polarographic tissue oxygen monitor (PmO2) and the InSpectra near-infrared spectrometer (StO2). We hypothesized that deltoid muscle tissue oxygenation measurements could detect patients in "occult shock" who are at increased risk for post-injury complications. The study was designed to (1) define values for PmO2 and StO2 in patients who by all standard measures appeared to be clinically resuscitated; (2) evaluate the relationship between PmO2, StO2 and other physiologic variables including mean arterial pressure (MAP), lactate and base deficit (BD); and (3) examine the relationship between early low tissue oxygen values and the subsequent development of infections and organ dysfunction. Licox probes were inserted into the deltoid muscle of critically injured patients after initial surgical and radiologic interventions, and transcutaneous StO2 monitors were applied over the same muscle bed. PmO2, StO2, and standard physiologic data were collected continuously using a multimodal bioinformatics system. RESULTS: Twenty-eight critically injured patients were enrolled in this study at admission to the intensive care unit (ICU). For patients who appeared to be well resuscitated (defined as MAP > or = 70 mm Hg, heart rate [HR] < or = 110 bpm, BD > or = -2, and partial pressure of arterial oxygen (PaO2) = 80 and 150 mm Hg), the mean PmO2 was 34 +/- 11 mm Hg and StO2 was 63 +/- 27%. There was a strong relationship between PmO2 and BD (p < 0.001) but no significant relationship between StO2 and BD. The relationship between PmO2 and StO2 was weak but statistically significant. Early low values of both PmO2 and StO2 identified patients at risk for infectious complications or multiple organ failure (MOF). In patients who were well resuscitated by standard continuous parameters (HR and MAP), low PmO2 during the first 24 hours after admission (PmO2 < or = 25 for at least 2 hours) was strongly associated with the development of infectious complications (Odds Ratio = 16.5, 95% CI 1.49 to 183, p = 0.02). CONCLUSIONS: PmO2 is a responsive, reliable and continuous monitor of changes in base deficit. Initial low values for either PmO2 or StO2 were associated with post-injury complications. PmO2 monitoring may be useful in identifying patients in the state of occult underresuscitation who remain at risk for developing infection and MOF.

Adolescent↗

PubMed2006

Mental illness as an independent risk factor for unintentional injury and injury recidivism.

BACKGROUND: Twelve percent of Americans are diagnosed and treated for mental illness annually. The relationship between mental illness and intentional injuries such as assault and suicide has previously been described. However, unintentional injury among mentally ill adults has not been characterized. The purpose of this study was to identify relationships between mental illness diagnosis and unintentional injury. We hypothesized that diagnosed mental illness is an independent risk factor for unintentional injury and it increases the risk of recidivism. METHODS: In this retrospective cohort study, trauma registry data, medical records, and outpatient mental health care data from the San Francisco Department of Public Health Billing Information System (BIS) were used to identify patients admitted with unintentional injury at a Level I urban trauma center in 2003 and 2004. Data collected included mechanism of injury, patient outcome and disposition, mental health diagnoses, substance abuse history, presence of homelessness, number of repeat injury events, and outpatient mental health treatment history. The incidence of unintentional injury requiring admission to a trauma center and the risk of intentional injury recidivism in subjects with a mental illness diagnosis were compared with those in subjects without a mental illness diagnosis. The risk of recidivism in those who had received publicly funded outpatient treatment before their injury was also evaluated. RESULTS: Of the 1,709 patients admitted for unintentional injury, 20% had a diagnosis of mental illness. Individuals with mental illness had twice the rate of unintentional injury requiring admission (2.2-2.4 people in 1,000 vs. 1.0-1.1 in 1,000) and 4.5 times the odds of injury recidivism (odds ratio [OR] = 4.5, 95% confidence interval [CI] 3.3-6.1) as those who did not have a mental illness diagnosis. Mental illness was a more robust predictor of injury recidivism than substance abuse (OR = 3.2, 95% CI 2.3-4.3) or homelessness (OR = 2.3, 95% CI 1.5-3.4). Compared with the nonmentally ill group, subjects with mental illness had a longer hospital stay and were less likely to be discharged home. Also, their injuries were more likely the result of falling or being hit by cars, and less likely the result of motor vehicle collisions than subjects without mental illness. CONCLUSIONS: Mental illness is an independent risk factor for unintentional injury and injury recidivism. Individuals with mental illness also have a different pattern of injury and hospitalization. They tended to suffer from different mechanisms of injury, stayed in the hospital longer, and were more likely to be discharged to a skilled nursing facility. Recognition of mental illness as a risk factor for injury may prompt re-examination of resource allocation for mental health and injury prevention and highlights the mentally ill as a prime target population for unintentional injury prevention efforts.

Adolescent↗

PubMed2004

Thromboembolism after trauma: an analysis of 1602 episodes from the American College of Surgeons National Trauma Data Bank.

OBJECTIVE: Venous thromboembolic events (VTE) are potentially preventable causes of morbidity and mortality after injury. We hypothesized that the current clinical incidence of VTE is relatively low and that VTE risk factors could be identified. METHODS: We queried the ACS National Trauma Data Bank for episodes of deep venous thrombosis (DVT) and/or pulmonary embolism (PE). We examined demographic data, VTE risk factors, outcomes, and VTE prophylaxis measures in patients admitted to the 131 contributing trauma centers. RESULTS: From a total of 450,375 patients, 1602 (0.36%) had a VTE (998 DVT, 522 PE, 82 both), for an incidence of 0.36%. Ninety percent of patients with VTE had 1 of the 9 risk factors commonly associated with VTE. Six risk factors found to be independently significant in multivariate logistic regression for VTE were age > or = 40 years (odds ratio [OR] 2.01; 95% confidence interval [CI] 1.74 to 2.32), lower extremity fracture with AIS > or = 3 (OR 1.92; 95% CI 1.64 to 2.26), head injury with AIS > or = 3 (OR 1.24; 95% CI 1.05 to 1.46), ventilator days >3 (OR 8.08; 95% CI 6.86 to 9.52), venous injury (OR 3.56; 95% CI 2.22 to 5.72), and a major operative procedure (OR 1.53; 95% CI 1.30 to 1.80). Vena cava filters were placed in 3,883 patients, 86% as PE prophylaxis, including in 410 patients without an identifiable risk factor for VTE. CONCLUSIONS: Patients who need VTE prophylaxis after trauma can be identified based on risk factors. The use of prophylactic vena cava filters should be re-examined.

Adolescent↗

PubMed2003

Trauma assessment training with a patient simulator: a prospective, randomized study.

BACKGROUND: Patient simulators are computer-controlled mannequins that may increase realism during trauma training by providing real-time changes in vital signs and physical findings during trauma scenarios. We hypothesized that trauma assessment training on a patient simulator would be as effective as training with a more traditional moulage patient/actor. METHODS: This study was conducted during a surgery intern orientation at two academic trauma centers. Interns (n = 60) attended a basic trauma course, and were then randomized to trauma assessment practice sessions with either the patient simulator (n = 30) or a moulage patient (n = 30). After practice sessions, interns were randomized a second time to an individual trauma assessment test on either the simulator or the moulage patient. Two surgeon-judges rated each intern live and on video for completion of 50 predetermined assessment objectives (total score) divided into sections (primary and secondary survey, general performance, diagnostic studies/procedures, and plan) and the identification and management of an acute neurologic deterioration in the test patient (event score). Multiple linear regression with random student effects was used to estimate the independent effects of all study variables. RESULTS: Within randomized groups, mean trauma assessment test scores for all simulator-trained interns were higher when compared with all moulage-trained interns (71 +/- 8 vs. 66 +/- 8, respectively; p = 0.02). Simulator training independently showed a small but statistically significant improvement in both the total score and the event score (+4.6 and +8.6, respectively; p < 0.05). CONCLUSION: Use of a patient simulator to introduce trauma assessment training is feasible and compares favorably to training in a moulage setting. Continued research in this area of physician education is warranted.

Educational Measurement↗