Intra-aortic balloon pumping: concepts and patient care.

Definite indications for intra-aortic balloon support include cardiogenic shock (with or without complicating mechanical defects) following acute myocardial infarction, unstable angina pectoris refractory to medical therapy, and left ventricular failure following cardiopulmonary bypass. Balloon effectiveness is based upon diastolic augmentation and reduction of left ventricular pressures and work load, as well as an increase in coronary artery perfusion pressure. The highly skilled nursing management required by the patient with balloon assist is based upon the nursing process principles of assessment, planning, implementation, and evaluation, combined with a thorough knowledge of cardiovascular and other integral systems and balloon function and physiology.

New laser applications in geodetic and engineering surveys.

Large engineering constructions and first-order geodetic control nets often require a relative accuracy of 10(-6)or better in positioning of survey points. A team from the University of New Brunswick has developed new instruments for precision alignment surveys and for engineering and geodetic leveling which satisfy the demands for accuracy. Prototypes of integrating centering detectors have been designed and constructed which allow alignment of laser beams with an accuracy of 0.2 sec of arc in a turbulent atmosphere over distances of a few kilometers. Two types of laser plummets have been developed to set a laser beam in a vertical direction with an accuracy of 0.5 sec of arc or better. A He-Ne laser has been adapted to a conventional self-aligning level giving a standard error of 0.7 mm/km in determination of a difference in elevation. A new type of laser level has been constructed which gives new possibilities for precision leveling.