Haemodynamic consequences of warm cardiac irrigation during cardiac surgery

Canadian Journal of Anesthesia/Journal canadien d'anesthésie - Following cardiopulmonary bypass (CPB) and prior to closing the chest, some surgeons irrigate the heart and pericardium with...     

Prior carotid surgery does not affect the reliability of landmarks for location of the internal jugular vein

Twenty-one volunteer subjects who had undergone prior carotid endarterectomy (CEA) agreed to an ultrasound study of the neck. The transducer was held as one would hold a cannulating needle and ultrasound images were obtained of the great vessels in the neck. Each of two cannulating techniques was simulated on each side of every patient's neck. Photographs of the ultrasound images were analyzed to score "hit" or "miss" for the internal jugular vein (IJV) and the carotid artery (CA), and to measure both the angle between these vessels and the distance from the skin to the IJV. In 11 subjects, the effect of a Valsalva maneuver on IJV width was also determined. Owing to bilateral CEA in 9 of the 21 subjects, there were 12 studies of nonsurgical sides (NSS) and 30 studies of surgical sides (SS). SS and NSS hit frequencies were statistically indistinguishable both for the IJV and the CA. In no photograph did the IJV lie medial to the CA. A Valsalva maneuver did not change IJV width on either the SS or the NSS. These data show that prior CEA does not affect the location of the IJV. Tissue alterations or adhesions may render actual IJV cannulation more difficult or risky. The data suggest but do not prove that prior CEA may not increase the incidence of CA puncture under clinical conditions.     

Leukemic intestinal pneumatosis

A benign form of pneumatosis intestinalis has been reported in children with leukemia but also occurs in adults as we report here. Radiologists must be familiar with this entity or a mistaken diagnosis of an abdominal catastrophe will be made, committing the patient to unneccessary emergency surgery.     

Ximelagatran vs warfarin for stroke prevention in patients with nonvalvular atrial fibrillation: a randomized trial

Context  In patients with nonvalvular atrial fibrillation, warfarin prevents ischemic stroke, but dose adjustment, coagulation monitoring, and bleeding limit its use. Objective  To compare the efficacy of the oral direct thrombin inhibitor ximelagatran with warfarin for prevention of stroke and systemic embolism. Design, Setting, and Participants  Double-blind, randomized, multicenter trial (2000-2001) conducted at 409 North American sites, involving 3922 patients with nonvalvular atrial fibrillation and additional stroke risk factors. Interventions  Adjusted-dose warfarin (aiming for an international normalized ratio [INR] 2.0 to 3.0) or fixed-dose oral ximelagatran, 36 mg twice daily. Main Outcome Measures  The primary end point was all strokes (ischemic or hemorrhagic) and systemic embolic events. The primary analysis was based on demonstrating noninferiority within an absolute margin of 2.0% per year according to the intention-to-treat model. Results  During 6405 patient-years (mean 20 months) of follow-up, 88 patients experienced primary events. The mean (SD) INR with warfarin (2.4 [0.8]) was within target during 68% of the treatment period. The primary event rate with ximelagatran was 1.6% per year and with warfarin was 1.2% per year (absolute difference, 0.45% per year; 95% confidence interval, –0.13% to 1.03% per year; P<.001 for the predefined noninferiority hypothesis). When all-cause mortality was included in addition to stroke and systemic embolic events, the rate difference was 0.10% per year (95% confidence interval, –0.97% to 1.2% per year; P = .86). There was no difference between treatment groups in rates of major bleeding, but total bleeding (major and minor) was lower with ximelagatran (37% vs 47% per year; 95% confidence interval for the difference, –14% to –6.0% per year; P<.001). Serum alanine aminotransferase levels rose to greater than 3 times the upper limit of normal in 6.0% of patients treated with ximelagatran, usually within 6 months and typically declined whether or not treatment continued; however, one case of documented fatal liver disease and one other suggestive case occurred. Conclusions  The results establish the efficacy of fixed-dose oral ximelagatran without coagulation monitoring compared with well-controlled warfarin for prevention of thromboembolism in patients with atrial fibrillation requiring chronic anticoagulant therapy, but the potential for hepatotoxicity requires further investigation.      

Heart rate variability changes during pregnancy: an observational study

BACKGROUND: Autonomic nervous systemic imbalance, as reflected by altered heart rate variability, is associated with adverse clinical sequelae. Before heart rate variability can predict adverse responses to interventions at delivery, changes compared to the non-pregnant state should be explored. METHODS: Twenty-four normal healthy volunteer women and 22 pregnant women at term immediately before cesarean section, underwent various analyses of heart rate variability following a standard sampling. Calculations included time domain, frequency domain and non-linear measures. To make 14 comparisons between pregnant and volunteer subjects, a significance level of 0.00357 was taken. RESULTS: Compared to volunteers, pregnant patients had higher heart rates and blood pressures, and decreases in some time domain heart rate variability parameters. Frequency domain heart rate variability parameters remained unaffected by pregnancy. Non-linear analysis results all decreased numerically, but failed to achieve statistical significance. CONCLUSIONS: Future investigations seeking associations of heart rate variability parameters with clinical events in pregnant women at term should consider time domain and non-linear analyses.