Biological research for nursing
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The purpose of this study was to examine the relationship between Czosnyka and others' Pressure Reactivity Index (PRx) and neurologic outcome in patients with acute brain injury, including traumatic brain injury (TBI) and cerebrovascular pathology. PRx measures the correlation between arterial blood pressure and intracranial pressure waves and may reflect cerebral autoregulation in response to blood pressure changes. A negative PRx reflects intact cerebrovascular response, whereas a positive PRx reflects impaired response. ⋯ For those with cerebrovascular pathology, the effect was not significant (P = 0.10) and was in the opposite direction. For individuals with TBI, PRx may provide useful information related to cerebral autoregulation that is predictive of outcome. The meaning of PRx in individuals with cerebrovascular pathology is unclear, and further study is needed to examine the paradoxical findings observed.
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Comparative Study
Comparison of autonomic nervous system indices based on abdominal pain reports in women with irritable bowel syndrome.
Abdominal pain is an important symptom in irritable bowel syndrome (IBS), but patients report typical pain intensities ranging from mild to very severe. In a sample of women, the authors sought to determine whether measures of systemic autonomic activity are related to self-reported pain intensity and the occurrence of pain in the postprandial period. ⋯ Even after statistically controlling for age, body mass index, and psychological distress, vagal heart rate variability measures were markedly lower in women reporting high pain (P < 0.01) and markedly higher in women reporting postprandial pain (P < 0.02). The vagal component of heart rate variability appears to be reduced in women with severe abdominal pain, especially in those whose pain is not postprandial.
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The immediate transition from positive pressure mechanical ventilation to spontaneous ventilation may generate significant cardiopulmonary hemodynamic alterations based on the mode of weaning selected, particularly in individuals with preexisting cardiac dysfunction. The purpose of this study was to compare hemodynamic responses associated with the initial transition to 3 modes of ventilator weaning (spontaneous ventilation/T-piece, pressure support [PS], and continuous positive airway pressure [CPAP]). Right ventricular hemodynamic responses were evaluated with a thermodilution pulmonary artery catheter; while left ventricular hemodynamic responses were measured by a transducer-tipped Millar catheter and conductance catheter. ⋯ Baseline ventricular function influenced hemodynamic response to the immediate transition from mechanical to spontaneous ventilation. There were also differential hemodynamic responses based on the ventilatory mode. Consideration of baseline cardiac function may be an important factor in the selection of an appropriate mode of spontaneous ventilation following controlled MV.
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Comparative Study
Effect of aerobic fitness on the physiological stress response in women.
Stress reactivity was assessed in aerobically fit (n = 14) and unfit (n = 8) females during the follicular phase of the menstrual cycle. Participants completed the Spielberger State-Trait Anxiety Inventory and provided a urine sample for catecholamine analysis before and after mental stress testing, Stroop Color-Word Test. ⋯ Fit and unfit participants differed significantly in baseline heart rate but not in stress reactivity or in state or trait anxiety. These data suggest that aerobic fitness does not attenuate the stress response in women prior to menopause.