Cardiopulmonary bypass (CPB) is the keystone that enables heart surgery to be safely performed on... more Cardiopulmonary bypass (CPB) is the keystone that enables heart surgery to be safely performed on hundreds of thousands of patients around the world each year. During CPB, two crucial factors, the oxygen content of arterial blood and the pump flow rate, determine whether sufficient oxygen is supplied to the body to match its metabolic demands. With modern oxygenators, full oxygenation of the arterial blood is easily achieved. However, the pump flow rate remains important as both too low and too high flow rates may be harmful.
... In contrast, neither Parolari and colleagues31 nor van der Heijden and colleagues33 concurred... more ... In contrast, neither Parolari and colleagues31 nor van der Heijden and colleagues33 concurred as both meta-analyses, using a composite outcome that included stroke, found only a nonsignificant trend toward a lower incidence of stroke with off-pump CABG surgery.31,33 A ...
The article of Yoshitani et al.(1) regarding cerebral hypoperfusion and cognitive outcome after c... more The article of Yoshitani et al.(1) regarding cerebral hypoperfusion and cognitive outcome after cardiac surgery has some limitations (1). The arterial carbon dioxide tension (Pa co 2) values reveal a large degree of variance. As Pa co 2 is a fundamental determinant of Sjv o ...
We reported that a decline in cognitive performance 3 mo after coronary artery bypass grafting su... more We reported that a decline in cognitive performance 3 mo after coronary artery bypass grafting surgery is associated with palpable aortic atheroma, but not postoperative jugular bulb oxyhemoglobin saturation (SjO2) <50%. However, the effect of SjO2 on clinical neurologic findings is not known. S100beta is a possible surrogate biochemical marker of brain injury, and we report here the scored clinical neurologic findings in 98 patients from our previous study in relation to SjO2, cognitive performance, aortic atheroma, and S100beta. Patients underwent a scored neurologic examination and cognitive assessment the day before and 3 mo after coronary artery bypass grafting surgery. Intraoperatively, intermittent blood sampling was performed, and postoperatively, the area under the curve describing SjO2 <50% in relation to time was calculated from continuous jugular bulb reflectance oximetry. Palpation was used to assess the ascending aorta for the presence of atheroma. The jugular bulb concentration of S100beta was measured 6 h after completion of surgery. The neurologic score 3 mo after surgery did not correlate with either intra- or postoperative SjO2 (r = 0.111, P = 0.278; and r = -0.074, P = 0.467, respectively). The main determinant of neurologic score at 3 mo was the preoperative neurologic score (r(2) = 0.63, P < 0.001), whereas palpable atheroma of the ascending aorta made a small but significant contribution (r(2) = 0.034, P = 0.004). Neurologic and cognitive scores correlated before surgery (r = 0.226, P = 0.022) and at 3 mo after surgery (r = 0.348, P < 0.001). A preoperative neurologic deficit of two or more had a small but significant negative effect on cognitive performance at 3 mo (standardized beta = -0.097, P = 0.018). There was a significant univariate correlation between S100beta and the 3-mo neurologic score (r = -0.232, P < 0.05), but not a multivariate correlation (beta = -0.090, P = 0.156). Intraoperative jugular bulb oxyhemoglobin saturation (SjO2) and postoperative SjO2 <50% do not have an important influence on long-term neurologic outcome after coronary artery bypass graft surgery. Subtle preoperative neurology is associated with long-term cognitive decline, and aortic atheroma is a risk factor for both cognitive and neurologic decline.
Applied Cardiopulmonary Pathophysiology Acp, May 1, 2012
ABSTRACT Background: In the last two decades, coronary artery bypass grafting (CABG) surgery has ... more ABSTRACT Background: In the last two decades, coronary artery bypass grafting (CABG) surgery has increasingly been performed without cardiopulmonary bypass (CPB) that is ‘off-pump’. A strong motivation for performing CABG surgery off-pump was to avoid CPB which has been believed to cause of cognitive decline. However, accumulating evidence from systematic reviews and meta-analyses comparing on- and off-pump CABG surgery indicate that CPB may not be the cause of cognitive decline [1]. Several additional randomised controlled trials (RCTs) comparing cognition after on- and off-pump CABG surgery have been published since the last meta-analyses. Objectives: The aim of this study was to undertake a systematic review the literature and meta-analysis to compare cognition following on- and off-pump CABG surgery. Methods: RCTs comparing continuous measures of cognitive outcome after on- and off-pump CABG surgery were identified by literature searching. Data extraction enabled data from seven psychometric tests (Auditory Verbal Learning Test, Grooved Pegboard, Trail-Making A and B, Digit Symbol, Digit Span, and Stroop Colour Word Test) to be amalgamated. Data was grouped into early (< six months) and late (≥ six months) postoperative periods and analysed using Revman 5. Results: A systematic literature search conducted in Medline, Embase, PsychINFO and The Cochrane Library yielded 13 studies totalling 2285 patients that could be included in the meta-analysis. No significant differences were found between on- and off-pump groups in any of the psychometric tests in either early or late postoperative periods. Conclusions: To-date, this is the largest meta-analysis comparing cognition following on- and off-pump CABG surgery and the absence of difference is consistent with previous systematic reviews and meta-analyses. The results are highly suggestive that CPB may not be the cause cognitive decline associated with CABG surgery.
... Philadelphia: WB Saunders, 1984:157. 3. Winnie AP. ... pump prime dose. Given a normal adult ... more ... Philadelphia: WB Saunders, 1984:157. 3. Winnie AP. ... pump prime dose. Given a normal adult (65 kg body weight) the only difference between the 250 KIU/mL group in Nuttall's study and the Full-Dose group is the pump prime load (88 mg vs. 280 mg). ...
Recently, it was reported that cardiotomy suction blood contains high levels of S100. Therefore,... more Recently, it was reported that cardiotomy suction blood contains high levels of S100. Therefore, the reinfusion of suction blood may be responsible for the low predictive value of S100 for cognitive decline after cardiac surgery with cardiopulmonary bypass. Consequently, it is expected that off-pump cardiac surgery will result in a lower release of S100. Methods. S100 was measured after induction of anesthesia, at closure of the chest, and 8 hours and 20 hours after admittance at the intensive care unit in 187 patients randomly assigned to off-pump or on-pump coronary artery bypass grafting. In addition, arterio-jugular S100 differences were estimated in a subset of 61 patients. In a minority of the off-pump procedures, cell-saver blood was returned to the patients. Results.
Reductions in cerebral venous oxyhemoglobin saturation (SjO2) occur during the rewarming phase of... more Reductions in cerebral venous oxyhemoglobin saturation (SjO2) occur during the rewarming phase of hypothermic cardiopulmonary bypass (CPB). We prospectively investigated the effects of propofol on these reductions in SjO2 (SjO2 <50%). Fiberoptic jugular bulb catheters were inserted in 30 patients undergoing coronary artery bypass grafting. Patients were randomly allocated to a test or control group. Test group patients (n = 15) received a propofol IV infusion titrated to electroencephalographic burst suppression during CPB. No significant differences in SjO2 <50% were found between the groups either by blood sampling and bench oximetry or fiberoptic oximetry. The arteriovenous difference in lactate concentration became negative in 59 of 120 samples. Propofol was associated with an increased incidence of hypotension (mean arterial pressure <50 mm Hg) (P = 0.023), an increased requirement for vasoconstrictor therapy (P = 0.025), and increases in the lactate oxygen index (P < 0.01). Propofol, when administered in doses that produce electroencephalographic burst suppression, does not attenuate the frequency or extent of reductions of SjO2 below 50% during rewarming from hypothermic CPB. However, it is associated with arterial hypotension and an increase in cerebral anaerobic metabolism. Reductions in cerebral venous oxyhemoglobin saturation during the rewarming phase of cardiopulmonary bypass may be related to brain injury. When administered in doses sufficient to produce electroencephalographic burst suppression, propofol did not attenuate the frequency or extent of such reductions in cerebral venous oxyhemoglobin saturation.
ABSTRACT The field of Web development has evolved and diversified significantly in recent years, ... more ABSTRACT The field of Web development has evolved and diversified significantly in recent years, and narrowing the gap between the requirements of academia and the demands of industry remains a challenge. Moreover, many faculty members often struggle with knowing “how much” of a particular subject they should teach to their students and at what level. This small-scale, exploratory study seeks to uncover the existence of “threshold concepts” within Web development. Threshold concepts are the fundamental concepts which, once mastered, allow a learner to progress to a deeper understanding of a subject. An online questionnaire was sent out to 24 instructors within UK higher education institutions who teach Web development subjects. Nine participants responded to the questionnaire and interviews were conducted with five to discuss and expand on the responses provided, resulting in the identification of four areas that were perceived as difficult for students to grasp when learning Web development. Analysis of these areas suggests that threshold concepts do exist within the subject and we offer up two candidates for the field of Web development: basic programming principles and decomposition and abstraction. Designing a curriculum based on threshold concepts and less on the latest methods, tools, and techniques can go a long way in helping students to become experts in their chosen discipline.
Cardiopulmonary bypass (CPB) is the keystone that enables heart surgery to be safely performed on... more Cardiopulmonary bypass (CPB) is the keystone that enables heart surgery to be safely performed on hundreds of thousands of patients around the world each year. During CPB, two crucial factors, the oxygen content of arterial blood and the pump flow rate, determine whether sufficient oxygen is supplied to the body to match its metabolic demands. With modern oxygenators, full oxygenation of the arterial blood is easily achieved. However, the pump flow rate remains important as both too low and too high flow rates may be harmful.
... In contrast, neither Parolari and colleagues31 nor van der Heijden and colleagues33 concurred... more ... In contrast, neither Parolari and colleagues31 nor van der Heijden and colleagues33 concurred as both meta-analyses, using a composite outcome that included stroke, found only a nonsignificant trend toward a lower incidence of stroke with off-pump CABG surgery.31,33 A ...
The article of Yoshitani et al.(1) regarding cerebral hypoperfusion and cognitive outcome after c... more The article of Yoshitani et al.(1) regarding cerebral hypoperfusion and cognitive outcome after cardiac surgery has some limitations (1). The arterial carbon dioxide tension (Pa co 2) values reveal a large degree of variance. As Pa co 2 is a fundamental determinant of Sjv o ...
We reported that a decline in cognitive performance 3 mo after coronary artery bypass grafting su... more We reported that a decline in cognitive performance 3 mo after coronary artery bypass grafting surgery is associated with palpable aortic atheroma, but not postoperative jugular bulb oxyhemoglobin saturation (SjO2) <50%. However, the effect of SjO2 on clinical neurologic findings is not known. S100beta is a possible surrogate biochemical marker of brain injury, and we report here the scored clinical neurologic findings in 98 patients from our previous study in relation to SjO2, cognitive performance, aortic atheroma, and S100beta. Patients underwent a scored neurologic examination and cognitive assessment the day before and 3 mo after coronary artery bypass grafting surgery. Intraoperatively, intermittent blood sampling was performed, and postoperatively, the area under the curve describing SjO2 <50% in relation to time was calculated from continuous jugular bulb reflectance oximetry. Palpation was used to assess the ascending aorta for the presence of atheroma. The jugular bulb concentration of S100beta was measured 6 h after completion of surgery. The neurologic score 3 mo after surgery did not correlate with either intra- or postoperative SjO2 (r = 0.111, P = 0.278; and r = -0.074, P = 0.467, respectively). The main determinant of neurologic score at 3 mo was the preoperative neurologic score (r(2) = 0.63, P < 0.001), whereas palpable atheroma of the ascending aorta made a small but significant contribution (r(2) = 0.034, P = 0.004). Neurologic and cognitive scores correlated before surgery (r = 0.226, P = 0.022) and at 3 mo after surgery (r = 0.348, P < 0.001). A preoperative neurologic deficit of two or more had a small but significant negative effect on cognitive performance at 3 mo (standardized beta = -0.097, P = 0.018). There was a significant univariate correlation between S100beta and the 3-mo neurologic score (r = -0.232, P < 0.05), but not a multivariate correlation (beta = -0.090, P = 0.156). Intraoperative jugular bulb oxyhemoglobin saturation (SjO2) and postoperative SjO2 <50% do not have an important influence on long-term neurologic outcome after coronary artery bypass graft surgery. Subtle preoperative neurology is associated with long-term cognitive decline, and aortic atheroma is a risk factor for both cognitive and neurologic decline.
Applied Cardiopulmonary Pathophysiology Acp, May 1, 2012
ABSTRACT Background: In the last two decades, coronary artery bypass grafting (CABG) surgery has ... more ABSTRACT Background: In the last two decades, coronary artery bypass grafting (CABG) surgery has increasingly been performed without cardiopulmonary bypass (CPB) that is ‘off-pump’. A strong motivation for performing CABG surgery off-pump was to avoid CPB which has been believed to cause of cognitive decline. However, accumulating evidence from systematic reviews and meta-analyses comparing on- and off-pump CABG surgery indicate that CPB may not be the cause of cognitive decline [1]. Several additional randomised controlled trials (RCTs) comparing cognition after on- and off-pump CABG surgery have been published since the last meta-analyses. Objectives: The aim of this study was to undertake a systematic review the literature and meta-analysis to compare cognition following on- and off-pump CABG surgery. Methods: RCTs comparing continuous measures of cognitive outcome after on- and off-pump CABG surgery were identified by literature searching. Data extraction enabled data from seven psychometric tests (Auditory Verbal Learning Test, Grooved Pegboard, Trail-Making A and B, Digit Symbol, Digit Span, and Stroop Colour Word Test) to be amalgamated. Data was grouped into early (< six months) and late (≥ six months) postoperative periods and analysed using Revman 5. Results: A systematic literature search conducted in Medline, Embase, PsychINFO and The Cochrane Library yielded 13 studies totalling 2285 patients that could be included in the meta-analysis. No significant differences were found between on- and off-pump groups in any of the psychometric tests in either early or late postoperative periods. Conclusions: To-date, this is the largest meta-analysis comparing cognition following on- and off-pump CABG surgery and the absence of difference is consistent with previous systematic reviews and meta-analyses. The results are highly suggestive that CPB may not be the cause cognitive decline associated with CABG surgery.
... Philadelphia: WB Saunders, 1984:157. 3. Winnie AP. ... pump prime dose. Given a normal adult ... more ... Philadelphia: WB Saunders, 1984:157. 3. Winnie AP. ... pump prime dose. Given a normal adult (65 kg body weight) the only difference between the 250 KIU/mL group in Nuttall's study and the Full-Dose group is the pump prime load (88 mg vs. 280 mg). ...
Recently, it was reported that cardiotomy suction blood contains high levels of S100. Therefore,... more Recently, it was reported that cardiotomy suction blood contains high levels of S100. Therefore, the reinfusion of suction blood may be responsible for the low predictive value of S100 for cognitive decline after cardiac surgery with cardiopulmonary bypass. Consequently, it is expected that off-pump cardiac surgery will result in a lower release of S100. Methods. S100 was measured after induction of anesthesia, at closure of the chest, and 8 hours and 20 hours after admittance at the intensive care unit in 187 patients randomly assigned to off-pump or on-pump coronary artery bypass grafting. In addition, arterio-jugular S100 differences were estimated in a subset of 61 patients. In a minority of the off-pump procedures, cell-saver blood was returned to the patients. Results.
Reductions in cerebral venous oxyhemoglobin saturation (SjO2) occur during the rewarming phase of... more Reductions in cerebral venous oxyhemoglobin saturation (SjO2) occur during the rewarming phase of hypothermic cardiopulmonary bypass (CPB). We prospectively investigated the effects of propofol on these reductions in SjO2 (SjO2 <50%). Fiberoptic jugular bulb catheters were inserted in 30 patients undergoing coronary artery bypass grafting. Patients were randomly allocated to a test or control group. Test group patients (n = 15) received a propofol IV infusion titrated to electroencephalographic burst suppression during CPB. No significant differences in SjO2 <50% were found between the groups either by blood sampling and bench oximetry or fiberoptic oximetry. The arteriovenous difference in lactate concentration became negative in 59 of 120 samples. Propofol was associated with an increased incidence of hypotension (mean arterial pressure <50 mm Hg) (P = 0.023), an increased requirement for vasoconstrictor therapy (P = 0.025), and increases in the lactate oxygen index (P < 0.01). Propofol, when administered in doses that produce electroencephalographic burst suppression, does not attenuate the frequency or extent of reductions of SjO2 below 50% during rewarming from hypothermic CPB. However, it is associated with arterial hypotension and an increase in cerebral anaerobic metabolism. Reductions in cerebral venous oxyhemoglobin saturation during the rewarming phase of cardiopulmonary bypass may be related to brain injury. When administered in doses sufficient to produce electroencephalographic burst suppression, propofol did not attenuate the frequency or extent of such reductions in cerebral venous oxyhemoglobin saturation.
ABSTRACT The field of Web development has evolved and diversified significantly in recent years, ... more ABSTRACT The field of Web development has evolved and diversified significantly in recent years, and narrowing the gap between the requirements of academia and the demands of industry remains a challenge. Moreover, many faculty members often struggle with knowing “how much” of a particular subject they should teach to their students and at what level. This small-scale, exploratory study seeks to uncover the existence of “threshold concepts” within Web development. Threshold concepts are the fundamental concepts which, once mastered, allow a learner to progress to a deeper understanding of a subject. An online questionnaire was sent out to 24 instructors within UK higher education institutions who teach Web development subjects. Nine participants responded to the questionnaire and interviews were conducted with five to discuss and expand on the responses provided, resulting in the identification of four areas that were perceived as difficult for students to grasp when learning Web development. Analysis of these areas suggests that threshold concepts do exist within the subject and we offer up two candidates for the field of Web development: basic programming principles and decomposition and abstraction. Designing a curriculum based on threshold concepts and less on the latest methods, tools, and techniques can go a long way in helping students to become experts in their chosen discipline.
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