The Effect of Cardiopulmonary Bypass Perfusion Pressure on Myocardial Gas Tensions in the Presence of Coronary Stenosis

Khuri, Shukri F.; Brawley, Robert K.; O'Riordan, J; Donahoo, James S.; Pitt, Bertram; Gott, Vincent L.

doi:10.1016/s0003-4975(10)65759-1

Cited by 18 publications

(3 citation statements)

References 11 publications

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“…17 However, the present study considers fixed outflow resistances and ignores effects of cerebral autoregulation under the assumption that the drastic change in perfusion pressure and flow from a physiological to CPB scenario is too large to be compensated by autoregulation. 18 The time dependency of cerebral autoregulation cannot be completely discounted however and it may be possible to truly capture this effect using a more realistic approach to outflow resistance modeling that is capable of capturing the transition from physiological to CPB perfusion in a time-dependent fashion.…”

Section: Study Limitations and Future Directionmentioning

confidence: 99%

Aortic Outflow Cannula Tip Design and Orientation Impacts Cerebral Perfusion During Pediatric Cardiopulmonary Bypass Procedures

et al. 2013

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Abstract-Poor perfusion of the aortic arch is a suspected cause for peri-and post-operative neurological complications associated with cardiopulmonary bypass (CPB). High-speed jets from 8 to 10FR pediatric/neonatal cannulae delivering 1 L/min of blood can accrue sub-lethal hemolytic damage while also subjecting the aorta to non-physiologic flow conditions that compromise cerebral perfusion. Therefore, we emphasize the importance of cannulation strategy and hypothesize engineering better CPB perfusion through a redesigned aortic cannula tip. This study employs computational fluid dynamics to investigate novel diffuser-tipped aortic cannulae for shape sensitivity to cerebral perfusion, in an in silico cross-clamped aortic arch model modeled with fixed outflow resistances. 17 parametrically altered configurations of an 8FR end-hole and several diffuser cone angled tips in combination with jet incidence angles toward or away from the head-neck vessels were studied. Experimental pressure-flow characterizations were also conducted on these cannula tip designs. An 8FR end-hole aortic cannula delivering 1 L/min along the transverse aortic arch was found to give rise to backflow from the brachicephalic artery (BCA), irrespective of angular orientation, for the chosen ascending aortic insertion location. Parametric alteration of the cannula tip to include a diffuser cone angle (tested up to 7°) eliminated BCA backflow for any tested angle of jet incidence. Experiments revealed that a 1 cm long 10°diffuser cone tip demonstrated the best pressure-flow performance improvement in contrast with either an end-hole tip or diffuser cone angles greater than 10°. Performance further improved when the diffuser was preceded by an expanded four-lobe swirl inducer attachment-a novel component. In conclusion, aortic cannula orientation is crucial in determining net head-neck perfusion but precise angulations and insertion-depths are difficult to achieve practically. Altering the cannula tip to include a diffuser cone angle has been shown for the first time to have potential in ensuring a net positive outflow at the BCA. Cannula insertion distanced from the BCA inlet may also avoid backflow owing to the Venturi effect, but the diffuser tipped cannula design presents a promising solution to mitigate this issue irrespective of in vivo cannula tip orientation.

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Section: Study Limitations and Future Directionmentioning

confidence: 99%

Aortic Outflow Cannula Tip Design and Orientation Impacts Cerebral Perfusion During Pediatric Cardiopulmonary Bypass Procedures

et al. 2013

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“…Since the original description of the direct measurement of Pmcoj (Brantigan et al, 1972a), subsequent studies have confirmed the increase of Pmco? during myocardial ischemia or anoxia (Brantigan et al, 1972b;Furuse et al, 1973;Khuri et al, 1975aKhuri et al, , 1975bMacGregor et al, 1974;O'Riordan et al, 1977aO'Riordan et al, , 1977b. Even with lesser degrees of ischemia, it was observed (O'Riordan et aL, 1977b) that Pmcc>2 provides a much more sensitive index of ischemia than myocardial Pch measurements, since Pmcc^ changes more extensively; the magnitude of PmccHi rise also was related to the degree of S-T segment change (O'Riordan et al, 1977a, Khuri et al, 1975c.…”

Section: Discussionmentioning

confidence: 99%

Rate of rise of myocardial PCO2 during early myocardial ischemia in the dog.

Case¹,

Felix²,

Castellana³

1979

Circulation Research

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SUMMARYWe have investigated the rate of rise of myocardial Pco» (Pmco») after coronary artery occlusion using a new method for this measurement. Previous studies of Pmcch have been limited by the slow response of the only available method, and no increase in Pmcoi prior to 3 minutes after occlusion has been found. We have implanted a miniature PcOj electrode, with a 63% response time of 14 seconds, into the left ventricle of 14 open-chest dogs. After abrupt coronary occlusion, Pmcoi began to rise in 13.6 ± 1.1 seconds in heparinized dogs and in 7.5 ± 0.7 seconds in unheparinized dogs. The subsequent magnitude of the increase in Pmcoi was 24, 88, 171, and 222 mm Hg at 2, 5, 10, and 15 minutes after occlusion. The rate of rise of Pmcoi was essentially linear from 1 minute to 10 minutes at a rate of 18.3 mm Hg/min. The rate of rise was slower during the first 30 seconds after occlusion (6.1 mm Hg/min) and also from 30 seconds to 1 minute (9.7 mm Hg/min). This rate of rise is much greater than that previously observed and reflects the severe myocardial acidosis developing during ischemia. A rise in Pmco, is one of the earliest metabolic changes that has been observed during myocardial ischemia. Ore Res 45:324-330, 1979

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“…Myocardial acidosis before AC is indicative of myocardial ischemia that can be due to the severity of the patient's underlying coronary artery disease or to the conditions of perfusion, such as low systemic perfusion pressure in the presence of coronary artery obstruction or left ventricular hypertrophy. 24 Regional myocardial acidosis during AC has been shown to relate to adverse short-term clinical outcomes. 2,7,11 In our models, regional myocardial acidosis during this period had the highest risk ratio and was the most important myocardial pH variable in affecting long-term survival; it was also more important than the other 4 non-pH variables in the model.…”

Section: Table 2 Optimum Threshold Points Of Continuous Variables With Automatic Interaction Detection Algorithm With Mortality During Pementioning

confidence: 99%

Intraoperative regional myocardial acidosis and reduction in long-term survival after cardiac surgery

Khuri

Healey

Hossain³

et al. 2005

The Journal of Thoracic and Cardiovascular Surgery

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The Effect of Cardiopulmonary Bypass Perfusion Pressure on Myocardial Gas Tensions in the Presence of Coronary Stenosis

Cited by 18 publications

References 11 publications

Aortic Outflow Cannula Tip Design and Orientation Impacts Cerebral Perfusion During Pediatric Cardiopulmonary Bypass Procedures

Aortic Outflow Cannula Tip Design and Orientation Impacts Cerebral Perfusion During Pediatric Cardiopulmonary Bypass Procedures

Rate of rise of myocardial PCO2 during early myocardial ischemia in the dog.

Intraoperative regional myocardial acidosis and reduction in long-term survival after cardiac surgery

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