John P. Abenstein

The incidence of artery puncture with central venous cannulation using a modified technique for detection and prevention of arterial cannulation

BACKGROUND Cannulation of the central circulation is essential for management of patients who require major surgery, and for patients who are critically ill. Arterial puncture is the most frequent complication associated with central venous cannulation, and is potentially fatal. Detection of arterial puncture can be problematic, especially in patients with cyanotic congenital heart disease. METHODS One thousand eleven consecutive cardiothoracic and vascular surgical patients who required central venous cannulation were studied using a new technique for detection of arterial puncture and prevention of arterial cannulation. This technique involves continuous pressure transduction of the steel introducer needle. Central venous cannulation was attempted in all patients. The sites of attempted catheterizations, number of arterial punctures and cannulations, and the number of successful catheterizations were noted. All patients were treated in accordance with standard anesthetic and surgical techniques in the institution. RESULTS One thousand one hundred seventy-two central venous catheters were placed. The overall success rate was 99.6%. The incidence of arterial puncture was 9.3% for central venous cannulation attempts of the internal jugular, subclavian, and femoral veins. No arterial cannulation occurred, and none of the patients had significant complications. Congenital heart disease patients had a higher incidence of arterial puncture (14.1%) and a lower rate (96.8%) of successful cannulation. CONCLUSION Pressure transduction of the steel needle is a useful technique for detecting arterial puncture and preventing arterial cannulation during attempts to achieve central venous cannulation.

A randomized comparison of ketamine versus methohexital anesthesia in electroconvulsive therapy.

To assess the clinical utility of ketamine as an anesthetic agent for electroconvulsive therapy (ECT), based upon recent findings that ketamine may have antidepressant properties. Depressed ECT patients were randomly assigned to receive anesthesia with either ketamine or methohexital. Outcome measures included assessments of depressive severity, cognition, post-anesthesia side effects, and hemodynamics. Twenty one patients were treated with ketamine and 17 with methohexital. There were no significant differences in depression or cognitive outcomes between the two drugs. Additionally, there were no measures of post-anesthesia tolerability or hemodynamics which favored ketamine. Ketamine anesthesia does not accelerate the antidepressant effect of ECT or diminish the cognitive side effects, at least as measured in this study. Furthermore, there is no apparent benefit of ketamine for speed or quality of post-ECT recovery, and it is associated with higher systolic blood pressures after the treatments. Ketamine is associated with longer motor seizure duration than methohexital.

Cellular Telephone Interference With Medical Equipment

OBJECTIVE To assess the potential electromagnetic interference (EMI) effects that new or current-generation cellular telephones have on medical devices. MATERIAL AND METHODS For this study, performed at the Mayo Clinic in Rochester, Minn, between March 9, 2004, and April 24, 2004, we tested 16 different medical devices with 6 cellular telephones to assess the potential for EMI. Two of the medical devices were tested with both new and old interface modules. The 6 cellular telephones chosen represent the different cellular technology protocols in use: Code Division Multiple Access (2 models), Global System for Mobile communications, Integrated Digital Enhanced Network, Time Division Multiple Access, and analog. The cellular telephones were tested when operating at or near their maximum power output. The medical devices, connected to clinical simulators during testing, were monitored by observing the device displays and alarms. RESULTS Of 510 tests performed, the incidence of clinically important interference was 1.2%; EMI was Induced in 108 tests (21.2%). Interference occurred in 7 (44%) of the 16 devices tested. CONCLUSIONS Cellular telephones can interfere with medical equipment. Technology changes in both cellular telephones and medical equipment may continue to mitigate or may worsen clinically relevant interference. Compared with cellular telephones tested in previous studies, those currently in use must be closer to medical devices before any interference is noticed. However, periodic testing of cellular telephones to determine their effects on medical equipment will be required.

Comparison of axillary artery or brachial artery pressure with aortic pressure after cardiopulmonary bypass using a long radial artery catheter

Arterial pressure measured in a peripheral artery may significantly underestimate central arterial pressure after discontinuation of cardiopulmonary bypass (CPB). Arterial pressure measured with a 50 cm radial artery catheter advanced into the brachial or axillary artery was compared to ascending aortic pressure in 31 patients before and after discontinuation of CPB. The radial artery catheter extended proximally into the brachial artery in 8/31 patients, and into the axillary artery in 23/31 patients. The patients age, pre-CPB cardiac ejection fraction, and surgical procedures were similar in both groups. The systolic arterial pressure measured in the ascending aorta was found to be significantly different from that in the axillary artery after CPB, whereas the mean and diastolic pressures were not. The average aorta-to-axillary artery systolic pressure gradient was -3.0 +/- 4.0 mmHg, with no patient having a gradient greater than 10 mmHg. The systolic and mean arterial pressures measured in the ascending aorta were found to be significantly different from that in the brachial artery after discontinuation of CPB, whereas the diastolic pressure was not. The average aorta-to-brachial artery systolic pressure gradient was 6.9 +/- 6.9 mmHg, with 3/8 patients having a gradient greater than 10 mmHg. Long radial artery catheters, placed using the Seldinger technique, provide an accurate estimate of central aortic pressure after CPB when they are advanced into the axillary artery. Sites more distal than the axillary artery may result in significant underestimation of the central aortic pressure in these patients.

Is Physician Anesthesia Cost-Effective?

One of the most controversial issues in anesthesia is whether nonmedically directed nurse anesthetists are relatively more cost-effective than anesthesiologists in the provision of anesthesia care. We electronically surveyed anesthesia practices throughout the United States to estimate the range in anesthesia professional costs from the payer perspective. Using this survey data on anesthesia reimbursement and published outcomes studies, we developed an ad hoc model to estimate the cost-effectiveness of physician-directed anesthesia relative to a nonmedically directed nurse anesthetist model of care from the payer perspective. Cost-effectiveness ratios were defined as the ratio of incremental costs associated with physician anesthesia relative to the estimated incremental life expectancy gains with this model of care (i.e., dollars per year of life saved [

Computerized Bar Code–Based Blood Identification Systems and Near-Miss Transfusion Episodes and Transfusion Errors

/YLS]). Reference case results suggest that physician anesthesia is cost saving with an estimated incremental cost-effectiveness ratio of −

An ounce of prevention may equate to a pound of cure: can early detection and intervention prevent adverse events?

2,601/YLS for a younger privately insured patient and an estimated cost-effectiveness ratio of −

Characteristics of Emergency Pages Using a Computer-Based Anesthesiology Paging System in Children and Adults Undergoing Procedures at a Tertiary Care Medical Center

4,410/YLS for an elderly Medicare insured patient. Cost-effectiveness ratios ranged from −

Ventilator Alarm Failure Due to Modification of the Scavenging System

4,410 to

Communication Technology: Patient Safety and the Patient-Physician Relationship

38,778/YLS in univariate and multivariate sensitivity analyses across payer types. Results were most sensitive to assumed differences in reimbursement (commercial conversion factors) and to mortality rate assumptions by provider type. This analysis offers economic evidence in support of the physician anesthesia model of care.