No abstract

ABSTRACT. The response of cerebral blood volume (CBVR) to a small induced change in arterial carbon dioxide tension was studied by near-infrared spectroscopy in 17 newborn infants born from 26 wk of gestation to term. All 17 infants were undergoing mechanical ventilation but had apparently normal brains. The CBVR per kPa change in arterial carbon dioxide tension within the range 3.9 to 9.6 kPa was calculated from the change in total cerebral Hb concentration (

No abstract

Background: The perioperative management of antiplatelet therapy in noncardiac surgery patients who have undergone previous percutaneous coronary intervention (PCI) remains a dilemma. Continuing dual antiplatelet therapy (DAPT) may carry a risk of bleeding, while stopping antiplatelet therapy may increase the risk of perioperative major adverse cardiovascular events (MACE). Methods: Occurrence of Bleeding and Thrombosis during Antiplatelet Therapy In Non-Cardiac Surgery (OBTAIN) was an international prospective multicentre cohort study of perioperative antiplatelet treatment, MACE, and serious bleeding in noncardiac surgery. The incidences of MACE and bleeding were compared in patients receiving DAPT, monotherapy, and no antiplatelet therapy before surgery. Unadjusted risk ratios were calculated taking monotherapy as the baseline. The adjusted risks of bleeding and MACE were compared in patients receiving monotherapy and DAPT using propensity score matching. Results: A total of 917 patients were recruited and 847 were eligible for inclusion. Ninety-six patients received no antiplatelet therapy, 526 received monotherapy with aspirin, and 225 received DAPT. Thirty-two patients suffered MACE and 22 had bleeding. The unadjusted risk ratio for MACE in patients receiving DAPT compared with monotherapy was 1.9 (0.93e3.88), P¼0.08. There was no difference in MACE between no antiplatelet treatment and monotherapy 1.03 (0.31e 3.46), P¼0.96. Bleeding was more frequent with DAPT 6.55 (2.3e17.96) P¼0.0002. In a propensity matched analysis of

ARTERIAL HYPERTENSION requiring i.v. vasodilator therapy occurred early after coronary artery bypass surgery in approximately two out of three patients in an earlier study from this institution.' Although nitroglycerin is often viewed predominantly as a venodilator, our clinical studies of i.v. nitroglycerin in patients with acute myocardial infarction clearly indicate that, at higher infusion rates, nitroglycerin is also a potent arterial dilator. Nitroglycerin reduced both left ventricular filling pressure and mean arterial pressure, while stroke volume remained constant or increased.2' s Lowering of peripheral vascular resistance was greatest in patients who had hemodynamic evidence of severe left ventricular failure.In the present study, we used a randomized crossover protocol to determine whether i.v. nitroglycerin could be as effective as sodium nitroprusside in reducing arterial pressure in patients who were acutely hypertensive after coronary bypass. Previous studies have shown that nitroglycerin and nitroprusside can have opposite effects on the severity of regional ischemia.' 6 In these studies, nitroglycerin improved regional ischemia by increasing intercoronary collateral flow, while nitroprusside appeared to worsen ischemia by decreasing coronary perfusion pressure without improving collateral flow. Thus, if i.v. nitroglycerin is equally effective for treating acute hyper-