Arterial pressure waveform analysis versus thermodilution cardiac output measurement during open abdominal aortic aneurysm repair: a prospective observational study.

BACKGROUND: Arterial pressure waveform analysis enables continuous, minimally invasive measurement of cardiac output. Haemodynamic instability compromises the reliability of the technique and a means of maintaining accurate measurement in this circumstance would be useful. OBJECTIVES: To investigate the accuracy, precision and trending ability of arterial pressure waveform cardiac output obtained with FloTrac/Vigileo, versus pulmonary artery thermodilution in patients undergoing elective open abdominal aortic aneurysm repair. DESIGN: A prospective observational study. SETTING: Operating room in a university hospital. PATIENTS: Twenty-two patients scheduled for elective, open abdominal aortic aneurysm repair. MAIN OUTCOME MEASURES: Bias, limits of agreement and mean error as determined with Bland-Altman analysis between arterial waveform and thermodilution cardiac output assessment at four time points: after induction of anaesthesia (t1); after aortic cross-clamping (t2); after clamp release (t3); and after skin closure (t4). Trending ability from t1 to t2, t2 to t3 and t3 to t4, determined with four-quadrant and polar plot methodology. Clinically acceptable boundaries were defined in advance. RESULTS: Bland-Altman analysis revealed a bias of 0.54 l min (thermodilution minus arterial waveform cardiac output) for pooled data, and 0.51 (t1), -0.42 (t2), 0.98 (t3) and 0.98 (t4) l min at the different time points. Limits of agreement (LOA) were [-3.0 to 4.0] (pooled), [-2.0 to 3.0] (t1), [-3.1 to 2.3] (t2), [-2.5 to 4.4] (t3) and [-1.7 to 3.7] (t4) l min, resulting in mean errors of 58% (pooled), 45% (t1), 53% (t2), 52% (t3) and 41% (t4). Four-quadrant concordance was 65%. Polar plot analysis resulted in an angular bias of -12°, with radial LOA of -60° to 36°. CONCLUSION: Bias between arterial waveform and thermodilution cardiac output was within a predefined acceptable range, but the mean error was above the accepted range of 30%. Trending ability was poor. Arterial waveform and thermodilution cardiac outputs are, therefore, not interchangeable in patients undergoing open abdominal aortic aneurysm repair.

Calcium-lowering medications in patients with primary hyperparathyroidism: intraoperative findings and postoperative hypocalcemia.

BACKGROUND: We analyzed how calcium-lowering medications (CLMs) influenced surgical findings in patients with primary hyperparathyroidism. METHODS: A retrospective review was conducted of 281 patients undergoing surgery for primary hyperparathyroidism. Logistic regression evaluated the relationship between CLM and surgical findings. A mixed-effects model determined the influence of CLMs on these curves. RESULTS: We found that CLM (P = .018) and a higher serum calcium level (P = .018) were variables making 4-gland hyperplasia less likely. Analysis of intraoperative parathyroid hormone (IOPTH) plots revealed that CLMs altered the kinetics (P = .043). However, the 2 groups did not differ in the number of measurements necessary for a 50% decrease in IOPTH levels. Multivariate logistic regression also revealed that patients taking more than one CLM had an increased association with postoperative hypocalcemia (P = .018). CONCLUSIONS: Although CLM contributed to differences in IOPTH curves, their use does not require changing standard IOPTH protocol but should alert the surgeon to the risk of postoperative hypocalcemia.

Redefining success as significance through leadership in the new economy.

This review re-examines our current definition of success in the current economic system and challenges the surgeon to play a significant part in role modeling and mentoring surgical residents and other healthcare professionals. Leadership skills are presented and implementation strategies are suggested.