Comparison between intrathoracic blood volume and cardiac filling pressures in the early phase of hemodynamic instability of patients with sepsis or septic shock

PURPOSE: The purpose of this study was to analyze three different variables of cardiac preload; central venous pressure (CVP), pulmonary artery occlusion pressure (PAOP), and intrathoracic blood volume index (ITBVI) that served as the best indicator of cardiac function, that is, cardiac index (C1) or stroke index (SI). MATERIALS AND METHODS: This was a prospective study in 57 critically ill patients with sepsis or septic shock in whom 581 hemodynamic profiles were analyzed. One patient was included a second time after a period of 6 weeks. All patients were sedated and mechanically ventilated. Each patient had a 7.5-Frfive-lumen pulmonary artery catheter (PAC) and a 4-Fr catheter with an integrated thermistor and fiberoptic that was advanced into the descending aorta via a femoral artery sheath. The study was performed in the surgical intensive care unit of a university hospital. RESULTS: Linear regression analysis of the first profile for each case (n = 58) revealed a significant correlation between ITBVI and SI (r = 0.66). For comparison, correlations for PAOP/SI (r = 0.06) and CVP/SI (r = 0.10) were poor. The analysis of all second profiles showed that only the change in ITBVI reflected the change in SI (r = 0.67), whereas PAOP (r = 0.07) and CVP (r = 0.05) failed. Furthermore, a positive change in SI (n = 265) was most often associated with an increase in ITBVI (n = 189, 71.3%), less for PAOP (n = 122, 46.0%) and CVP (n = 137, 51.7%). A reduction in SI (n = 256) was accompanied by a decrease in ITBVI (n = 176, 68.8%), PAOP (n = 119, 46.5%), and CVP (n = 118, 46.1%). An increase in ITBVI (n = 269) was accompanied by an increase in SI in 189 cases (70.3%). In these, PAOP increased only in 91 (48.1%) and CVP in 101 cases (53.4%), respectively. Accordingly, a positive change in PAOP (n = 218) was associated with an increase in SI in 122 cases (56.0%). ITBVI increased in 91 (74.6%) and CVP in 84 (68.9%) of these cases. A decrease in ITBVI (n = 250) was associated with a decrease in SI in 176 cases (70.4%). Decreases in PAOP (n = 89, 50.6%) and CVP (n = 91, 51.7%) did not reflect these changes. However, when PAOP (n = 229) and SI decreased (n = 119, 52.0%), ITBVI decreased in 89 (74.8%) and CVP in 73 cases (61.3%). CONCLUSIONS: In comparison with cardiac filling pressures, ITBVI seems to be the more reliable indicator of cardiac preload in patients with sepsis or septic shock.     

Insulin status differentially affects energy transduction in cerebral mitochondria from male and female rats

Effects of STZ diabetes and treatment with insulin on cerebral mitochondrial metabolism in the male and female rats were examined. Diabetic state resulted in generalized decrease in the state 3 respiration rates in the males with practically all the substrates except glutamate where the opposite effect was seen. Diabetic state had no adverse effect on the respiratory activity in the females. Insulin treatment had no restorative effect in the males. By contrast in the females, adverse effects were noted. The cytochromes contents decreased in STZ diabetes with the effect being more pronounced in the males; treatment with 1 unit of insulin restored the cytochromes contents. STZ diabetes also resulted in decreased dehydrogenases activities with the effect being more pronounced in the females: insulin treatment resulted in hyper-stimulation of glutamate dehydrogenase and succinate DCIP reductase activities; restoration of malate dehydrogenase activity was only partial. The results point out that STZ diabetes and insulin treatments differentially affect cerebral mitochondrial energy metabolism in the male and female rats.     

The effect of methylphenidate on the sleep-wake cycle of brain-injured patients undergoing rehabilitation

BACKGROUND AND PURPOSE: A number of neuro-stimulants are routinely used as part of post-acute care of hospitalized brain-injured patients. To our knowledge, the effect of these stimulants on the sleep-wake cycles of brain-injured patients undergoing rehabilitation has not been addressed. We examined the effect of one of the most commonly used neuro-stimulants, methylphenidate, on the sleep-wake behavior of brain-injured patients undergoing rehabilitation at a dedicated brain injury clinic. PATIENTS AND METHOD: For this study, records of patients admitted between January and December 1999 were scrutinized retrospectively for the data on observationally defined sleep-wake distribution. A total of 30 patients diagnosed with traumatic brain injury were identified as having been observed for a full 24h a day for at least 10 days. Some of these patients (n=17) were administered methylphenidate on clinical grounds. They served as the experimental group, while the unmedicated patients (n=13) served as controls. For the present analysis, the sleep-wake cycles were arbitrarily designated as nighttime and daytime, respectively. A cumulative sleep-wake quantity in a 24-h period was also observed. RESULT: The average number of hours of sleep during a 24-h period was not significantly different for the two cohorts. Similar trends emerged for the nighttime and daytime observations. On the whole, methylphenidate appears not to have unfavorable effects on sleep-wake cycles, presently defined as nighttime, daytime and 24-h, in the traumatic brain injury population. CONCLUSION: This study sought to gain better understanding of the effect of methylphenidate on daytime sleepiness and nighttime sleep, and the data suggest that administration of methylphenidate does not appear to have an adverse effect on sleep-wake quantity.     

Improving Teamwork, Confidence, and Collaboration Among Members of a Pediatric Cardiovascular Intensive Care Unit Multidisciplinary Team Using Simulation-Based Team Training

Findings show that simulation-based team training (SBTT) is effective at increasing teamwork skills. Postpediatric cardiac surgery cardiac arrest (PPCS-CA) is a high-risk clinical situation with high morbidity and mortality. Whereas adult guidelines managing cardiac arrest after cardiac surgery are available, little exists for pediatric cardiac surgery. The authors developed a post-PPCS-CA algorithm and used SBTT to improve identification and management of PPCS-CA in the pediatric cardiovascular intensive care unit. Their goal was to determine whether participation aids in improving teamwork, confidence, and communication during these events. The authors developed a simulation-based training course using common postcardiac surgical emergency scenarios with specific learning objectives. Simulated scenarios are followed by structured debriefings. Participants were evaluated based on critical performance criteria, key elements in the PPCS-CA algorithm, and Team Strategies and Tools to Enhance Performance and Patient Safety (Team STEPPS) principles. Surveys performed before, immediately after, and 3 months after participation evaluated perception of skill, knowledge, and confidence. The study had 37 participants (23 nurses, 5 cardiology/critical care trainees, 5 respiratory therapists, and 4 noncategorized subjects). Confidence and skill in the roles of team leader, advanced airway management, and cardioversion/defibrillation were increased significantly (p < 0.05) immediately after training and 3 months later. A significant increase (p < 0.05) also was observed in the use of Team STEPPS concepts immediately after training and 3 months later. This study showed SBTT to be effective in improving communication and increasing confidence among members of a multidisciplinary team during crisis scenarios. Thus, SBTT provides an excellent tool for teaching and implementing new processes.