Blood pressure wave propagation : a multisensor setup for cerebral autoregulation studies

Objective. Cerebral autoregulation is critically important to maintain proper brain perfusion and supply the brain with oxygenated blood. Non-invasive measures of blood pressure (BP) are critical in assessing cerebral autoregulation. Wave propagation velocity may be a useful technique to estimate BP but the effect of the location of the sensors on the readings has not been thoroughly examined. In this paper, we were interested in studying whether the propagation velocity of a pressure wave in the direction from the heart to the brain may differ compared with propagation from the heart to the periphery, as well as across different physiological tasks and/or health conditions. Using non-invasive sensors simultaneously placed at different locations of the human body allows for the study of how the propagation velocity of the pressure wave, based on pulse transit time (PTT), varies across different directions. Approach. We present a multi-sensor BP wave propagation measurement setup intended for cerebral autoregulation studies. The presented sensor setup consists of three sensors, one placed on each of the neck, chest and finger, allowing simultaneous measurement of changes in BP propagation velocity towards the brain and to the periphery. We show how commonly tested physiological tasks affect the relative changes of PTT and correlations with BP. Main results. We observed that during maximal blow, valsalva and breath hold breathing tasks, the relative changes of PTT were higher when PTT was measured in the direction from the heart to the brain than from the heart to the peripherals. In contrast, during a deep breathing task, the relative change in PTT from the heart to the brain was lower. In addition, we present a short literature review of the PTT methods used in brain research. Significance. These preliminary data suggest that the physiological task and direction of PTT measurement may affect relative PTT changes. The presented three-sensor setup provides an easy and neuroimaging compatible method for cerebral autoregulation studies by allowing measurement of BP wave propagation velocity towards the brain versus towards the periphery

The consideration of post-exercise impact on SCAT3 scores in athletes immediately following a head injury

Examine effects of high-intensity exercise and physical impacts during rugby match on self-report symptoms in The Sport Concussion Assessment Tool (SCAT3), and its ability to differentiate head-injured players from controls. Methods: Symptoms were assessed immediately following completion of a rugby match (median 60 minutes). Players removed from the match for assessment due to a head hit were classified as head injured. Controls completed match without head hit. Results: 209 players (67 female; 33 ± 13 years) participated with 80 experiencing a head injury. Symptom severity was significantly greater in head injured (26.2 ± 17.6) compared with controls (8.9 ± 11.5, P 16 symptom severity, misclassifying them as suspected concussion. There were no significant sex differences. Factor analysis produced four symptom clusters of which Headache was most discriminatory between the head injured (median = 1.7) and controls (median = 0.0). Conclusion: These findings demonstrate that exercise and contact during a game affect symptom assessment, increasing the likelihood of misclassifying players with suspected concussion. Factor characterization of symptoms associated with head injury using an exercised comparison group provides more useful discrimination. These results highlight the necessity for objective measures to diagnose concussions outside of symptom self-report

Human adaptations to multiday saturation on NASA NEEMO

Human adaptation to extreme environments has been explored for over a century to understand human psychology, integrated physiology, comparative pathologies, and exploratory potential. It has been demonstrated that these environments can provide multiple external stimuli and stressors, which are sufficient to disrupt internal homeostasis and induce adaptation processes. Multiday hyperbaric and/or saturated (HBS) environments represent the most understudied of environmental extremes due to inherent experimental, analytical, technical, temporal, and safety limitations. National Aeronautic Space Agency (NASA) Extreme Environment Mission Operation (NEEMO) is a space-flight analog mission conducted within Florida International University's Aquarius Undersea Research Laboratory (AURL), the only existing operational and habitable undersea saturated environment. To investigate human objective and subjective adaptations to multiday HBS, we evaluated aquanauts living at saturation for 9-10 days via NASA NEEMO 22 and 23, across psychologic, cardiac, respiratory, autonomic, thermic, hemodynamic, sleep, and body composition parameters. We found that aquanauts exposed to saturation over 9-10 days experienced intrapersonal physical and mental burden, sustained good mood and work satisfaction, decreased heart and respiratory rates, increased parasympathetic and reduced sympathetic modulation, lower cerebral blood flow velocity, intact cerebral autoregulation and maintenance of baroreflex functionality, as well as losses in systemic bodyweight and adipose tissue. Together, these findings illustrate novel insights into human adaptation across multiple body systems in response to multiday hyperbaric saturation

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Cerebral blood flow in the internal carotid artery throughout the menstrual cycle in young, healthy women

Previous reports suggest female sex hormones may affect cerebral blood flow and cerebral flow velocity in women. The purpose of this study was to examine whether changes in cerebral blood flow occur throughout the menstrual cycle phases that are associated with fluctuations in sex hormones in young, healthy women

Sex differences in cerebral autoregulation are unaffected by menstrual cycle phase in young, healthy women

Sex is known to affect the prevalence of conditions such as stroke. However, effects of sex on cerebral blood flow regulation are still not well understood. Critical to this understanding is how fluctuations in hormones across the menstrual cycle affect cerebral autoregulation. We measured autoregulation in the early follicular, late follicular, and midluteal phases during spontaneous and induced blood pressure oscillations in 26 young, healthy individuals (13 women and 13 men, age: 26 +/- 4 yr). Men participated three times, similar to 1-3 wk apart. Beat-by-beat blood pressure, heart rate, end-tidal CO2, and transcranial Doppler ultrasonography of the middle (MCA) and anterior (ACA) cerebral arteries were obtained. We did not find a difference in cerebral autoregulation across the menstrual cycle in women but found significantly improved autoregulation in the MCA and ACA of women compared with men. Women demonstrated significantly lower MCA gain (0.97 +/- 0.13 vs. 1.17 +/- 0.14%/mmHg, P = 0.001), higher MCA phase (46.1 +/- 12.6 vs. 35.8 +/- 7.9 degrees, P = 0.019), and higher ACA phase (40.5 +/- 10.8 vs 31.5 +/- 8.5 degrees, P = 0.040) during repeated squat-to-stand maneuvers. Women also had lower MCA gain (1.50 +/- 0.11 vs. 1.72 +/- 0.30%/mmHg, P = 0.029) during spontaneous fluctuations in pressure while standing and less of a decrease in MCA flow velocity (-18.7 +/- 2.7 vs. -23.2 +/- 6.0%, P = 0.014) during sit-to-stand maneuvers. Our results suggest that young women have improved cerebral autoregulation compared with young men regardless of menstrual cycle phase and that autoregulation is relatively robust to acute fluctuations in female sex hormones. Sex is known to affect the prevalence of conditions such as stroke. However, effects of sex on cerebral blood flow regulation are still not well understood. Critical to this understanding is how fluctuations in hormones across the menstrual cycle affect cerebral autoregulation. We measured autoregulation in the early follicular, late follicular, and midluteal phases during spontaneous and induced blood pressure oscillations in 26 young, healthy individuals (13 women and 13 men, age: 26 +/- 4 yr). Men participated three times, similar to 1-3 wk apart. Beat-by-beat blood pressure, heart rate, end-tidal CO2, and transcranial Doppler ultrasonography of the middle (MCA) and anterior (ACA) cerebral arteries were obtained. We did not find a difference in cerebral autoregulation across the menstrual cycle in women but found significantly improved autoregulation in the MCA and ACA of women compared with men. Women demonstrated significantly lower MCA gain (0.97 +/- 0.13 vs. 1.17 +/- 0.14%/mmHg, P = 0.001), higher MCA phase (46.1 +/- 12.6 vs. 35.8 +/- 7.9 degrees, P = 0.019), and higher ACA phase (40.5 +/- 10.8 vs 31.5 +/- 8.5 degrees, P = 0.040) during repeated squat-to-stand maneuvers. Women also had lower MCA gain (1.50 +/- 0.11 vs. 1.72 +/- 0.30%/mmHg, P = 0.029) during spontaneous fluctuations in pressure while standing and less of a decrease in MCA flow velocity (-18.7 +/- 2.7 vs. -23.2 +/- 6.0%, P = 0.014) during sit-to-stand maneuvers. Our results suggest that young women have improved cerebral autoregulation compared with young men regardless of menstrual cycle phase and that autoregulation is relatively robust to acute fluctuations in female sex hormones. NEW & NOTEWORTHY This is the first study to investigate thoroughly the effects of menstrual cycle phase and sex differences in cerebral autoregulation in young, healthy individuals. Cerebral autoregulation was unaffected by menstrual cycle phase during both repeated squat-to-stand and sit-to-stand maneuvers. However, women demonstrated significantly improved cerebral autoregulation in the middle and anterior cerebral arteries, suggesting women were able to maintain cerebral blood flow during changes in blood pressure more efficiently than men. NEW & NOTEWORTHY This is the first study to investigate thoroughly the effects of menstrual cycle phase and sex differences in cerebral autoregulation in young, healthy individuals. Cerebral autoregulation was unaffected by menstrual cycle phase during both repeated squat-to-stand and sit-to-stand maneuvers. However, women demonstrated significantly improved cerebral autoregulation in the middle and anterior cerebral arteries, suggesting women were able to maintain cerebral blood flow during changes in blood pressure more efficiently than men