Publications by authors named "Natalie Koons"

Background: This learning opportunity was designed to provide an interactive, virtual, educational anesthesiology program for interested medical students and to offer an opportunity to learn more about an institutional culture through a question and answer (Q&A) with program faculty preceptors for the 2020-2021 anesthesiology residency application cycle. We sought to identify if this virtual learning program was a valuable educational tool through a survey.

Methods: A short Likert-scale survey was sent to medical students before and after participation in a session using REDCap electronic data capture tool.

View Article and Find Full Text PDF

Background: Shock index (SI) equals the ratio of heart rate (HR) to systolic blood pressure (SBP) with clinical evidence that it is more sensitive for trauma patient status assessment and prediction of outcome compared with either HR or SBP alone. We used lower body negative pressure (LBNP) as a human model of central hypovolemia and compensatory reserve measurement (CRM) validated for accurate tracking of reduced central blood volume to test the hypotheses that SI: (1) presents a late signal of central blood volume status; (2) displays poor sensitivity and specificity for predicting the onset of hemodynamic decompensation; and (3) cannot identify individuals at greatest risk for the onset of circulatory shock.

Methods: We measured HR, SBP, and CRM in 172 human subjects (19-55 years) during progressive LBNP designed to determine tolerance to central hypovolemia as a model of hemorrhage.

View Article and Find Full Text PDF

Background: Females routinely receive bupivacaine for obstetric and regional anesthesia. An accidental overdose of bupivacaine can result in cardiotoxicity and cardiac arrest. Intralipid (ILP) rescues bupivacaine-induced cardiotoxicity in male rats.

View Article and Find Full Text PDF

Background: Based on previous experiments in nonhuman primates, we hypothesized that DO crit in humans is 5-6 ml O ·kg  min .

Study Design And Methods: We measured the compensatory reserve (CRM) and calculated oxygen delivery (DO ) in 166 healthy, normotensive, nonsmoking subjects (97 males, 69 females) during progressive central hypovolemia induced by lower body negative pressure as a model of ongoing hemorrhage. Subjects were classified as having either high tolerance (HT; N = 111) or low tolerance (LT; N = 55) to central hypovolemia.

View Article and Find Full Text PDF

Study Objective: Anesthesiologists are at high risk for needlestick injury. Such injuries pose a serious health threat from exposure to bloodborne pathogens. This retrospective analysis aimed to examine needlestick injury rate among anesthesia providers between 2010 and 2020 at the University of California Los Angeles, Department of Anesthesiology and Perioperative Medicine to determine specialty-specific factors associated with these injuries.

View Article and Find Full Text PDF

Osteosarcoma (OS) is an aggressive mesenchymal cell tumor that carries a poor long-term prognosis. Despite definitive surgery for the primary tumor and adjuvant chemotherapy, pulmonary metastasis is common and is the primary cause of morbidity. To improve outcomes for patients, we have developed and optimized a phenotypic screen for drugs that may target OS disseminated tumor cells (DTCs) and inhibit their metastatic outbreak rather than merely screening for cytotoxic activity against proliferating cells, as is commonly conducted in conventional drug discovery approaches.

View Article and Find Full Text PDF

Hemorrhage is a leading cause of death following traumatic injuries in the United States. Much of the previous work in assessing the physiology and pathophysiology underlying blood loss has focused on descriptive measures of hemodynamic responses such as blood pressure, cardiac output, stroke volume, heart rate, and vascular resistance as indicators of changes in organ perfusion. More recent work has shifted the focus toward understanding mechanisms of compensation for reduced systemic delivery and cellular utilization of oxygen as a more comprehensive approach to understanding the complex physiologic changes that occur following and during blood loss.

View Article and Find Full Text PDF

Background: Traumatic injuries were the most common reason for admission of pediatric patients to military hospitals during the recent wars in Iraq and Afghanistan. We compare survival and interventions between female and male pediatric casualties.

Materials And Methods: This is a secondary analysis of a previously described dataset from the Department of Defense Trauma Registry.

View Article and Find Full Text PDF

Hemorrhagic shock can be mitigated by timely and accurate resuscitation designed to restore adequate delivery of oxygen (DO ). Current doctrine of using systolic blood pressure (SBP) as a guide for resuscitation can be associated with increased morbidity. The compensatory reserve measurement (CRM) is a novel vital sign based on the recognition that the sum of all mechanisms that contribute to the compensatory response to hemorrhage reside in features of the arterial pulse waveform.

View Article and Find Full Text PDF

Background: Current out-of-hospital protocols to determine hemorrhagic shock in civilian trauma systems rely on standard vital signs with military guidelines relying on heart rate and strength of the radial pulse on palpation, all of which have proven to provide little forewarning for the need to implement early intervention prior to decompensation. We tested the hypothesis that addition of a real-time decision-assist machine-learning algorithm, the compensatory reserve measurement (CRM), used by combat medics could shorten the time required to identify the need for intervention in an unstable patient during a hemorrhage profile as compared with vital signs alone.

Methods: We randomized combat medics from the Army Medical Department Center and School Health Readiness Center of Excellence into three groups: group 1 viewed a display of no simulated hemorrhage and unchanging vital signs as a control (n = 24), group 2 viewed a display of simulated hemorrhage and changing vital signs alone (hemorrhage; n = 31), and group 3 viewed a display of changing vital signs with the addition of the CRM (hemorrhage + CRM; n = 22).

View Article and Find Full Text PDF

Hemorrhagic shock can be mitigated by timely and accurate resuscitation designed to restore adequate delivery of oxygen (DO2) by increasing cardiac output (CO). However, standard care of using systolic blood pressure (SBP) as a guide for resuscitation may be ineffective and can potentially be associated with increased morbidity. We have developed a novel vital sign called the compensatory reserve measurement (CRM) generated from analysis of arterial pulse waveform feature changes that has been validated in experimental and clinical models of hemorrhage.

View Article and Find Full Text PDF

Background: Hemorrhage remains the leading cause of death following traumatic injury in both civilian and military settings. Heart rate variability (HRV) and heart rate complexity (HRC) have been proposed as potential "new vital signs" for monitoring trauma patients; however, the added benefit of HRV or HRC for decision support remains unclear. Another new paradigm, the compensatory reserve measurement (CRM), represents the integration of all cardiopulmonary mechanisms responsible for compensation during relative blood loss and was developed to identify current physiologic status by estimating the progression toward hemodynamic decompensation.

View Article and Find Full Text PDF

Disturbance of normal homeostasis occurs when oxygen delivery and energy stores to the body's tissues fail to meet the energy requirement of cells. The work submitted in this review is important because it advances the understanding of inadequate oxygen delivery as it relates to early diagnosis and treatment of circulatory shock and its relationship to disturbance of normal functioning of cellular metabolism in life-threatening conditions of hemorrhage. We explored data from the clinical and exercise literature to construct for the first time a conceptual framework for defining the limitation of inadequate delivery of oxygen by comparing the physiology of hemorrhagic shock caused by severe blood loss to maximal oxygen uptake induced by intense physical exercise.

View Article and Find Full Text PDF

Circulating blood volume (BV) and maximal oxygen uptake (Vo) are physiological characteristics important for optimal human performance in aerospace and military operational environments. We tested the hypothesis that BV and Vo are lower in older people independent of sex. To accomplish this, a "data mining" effort of an historic database generated from NASA and U.

View Article and Find Full Text PDF

Heat stress followed by an accompanying hemorrhagic challenge may influence hemostasis. We tested the hypothesis that hemostatic responses would be increased by passive heat stress, as well as exercise-induced heat stress, each with accompanying central hypovolemia to simulate a hemorrhagic insult. In aim 1, subjects were exposed to passive heating or normothermic time control, each followed by progressive lower-body negative pressure (LBNP) to presyncope.

View Article and Find Full Text PDF