Protocols for wound management.

After 7 months of extensive research, wound management protocols were successfully developed and implemented at a 500-bed chronic care facility. The protocols gave registered nurses the authority and autonomy to initiate both treatment and preventive measures when caring for patients with pressure ulcers. The purpose of the protocols was twofold: (1) to prevent intact skin from breaking down and (2) to increase the healing rate of present ulcers.

Designing a product evaluation project using research principles.

Critical care nurses are frequently involved in the evaluation of products used to enhance patient care. The authors discuss how research principles can be incorporated into the design for product evaluation to provide reliable information for purchasing decisions and add to the existing body of nursing knowledge. Because of the increasing number of products available to critical care nurses, the authors describe how to use research principles to design a product evaluation study for several examples.

Cardiac electrophysiologic effects of fentanyl and combinations of fentanyl and neuromuscular relaxants in pentobarbital-anesthetized dogs.

The effects of fentanyl, both alone and in combination with pancuronium bromide or succinylcholine, on atrioventricular (AV) node and ventricular conduction times and refractory periods were studied. Twenty-four pentobarbital-anesthetized dogs were instrumented both with an intraaortic catheter to measure cardiac conduction times and, through a thoracotomy, with atrial and ventricular epicardial pacing electrodes to provide premature stimulation that would allow measurement of atrial and ventricular refractoriness. Fentanyl prolonged the RR interval in both low- (100 micrograms/kg) and high-dose (400 micrograms/kg) groups by 26 and 45%, respectively, and prolonged AV node conduction time by 28 and 25%, respectively. During atrial pacing at a rate sufficient to capture the atria, AV node conduction time lengthened in the low- and high-dose groups by 27 and 25%, respectively. Fentanyl also significantly lengthened AV node effective and functional refractory periods and ventricular effective refractory periods in both groups. Pancuronium (0.1 mg/kg) administered after fentanyl shortened RR intervals in the low- and high-dose groups by 14 and 22%, respectively, and shortened AV conduction times by 18 and 20%, respectively, but did not restore all values to baseline. Pancuronium significantly shortened AV node refractory periods in the low-dose but not the high-dose group. When administered after fentanyl, succinylcholine (2 mg/kg) significantly shortened the RR interval in the low- and high-dose groups by 14 and 12%, respectively. Succinylcholine shortened AV node conduction slightly but without significance and had no effect on cardiac refractoriness. His-Purkinje conduction remained unaffected by any drug intervention. These data demonstrate that fentanyl depresses cardiac conduction; subsequent administration of pancuronium and succinylcholine partially reverses this effect.

Pulmonary artery wedge pressure measurement during experimental pulmonary hypertension: comparison of techniques in relation to catheter-induced hemorrhage.

Two methods of wedging a pulmonary artery catheter were studied in dogs with experimental pulmonary hypertension secondary to left atrial balloon inflation. In Group 1 (N = 8), the catheter tips were located in a branch of the pulmonary artery so that wedge pressures were obtained with balloon inflation. In Group 2 (N = 8), the catheter tips were positioned 1 to 2 cm beyond the pulmonic valve and readvanced into a branch of the pulmonary artery for each wedge pressure determination. In both groups, wedge pressures were obtained using a balloon inflation volume of 0.8 mL. With left atrial hypertension, the pressure gradient across the inflated balloon (calculated as mean pulmonary artery pressure minus pulmonary artery wedge pressure) was lower than baseline (P < .05). Wedge pressures were determined every five minutes. After two hours, the lungs were removed and studied grossly for hemorrhage. The incidence of pulmonary hemorrhage was 50% in Group 1 dogs, but 0% in Group 2 dogs (P < .03). It is concluded that locating the catheter tip in the proximal pulmonary artery and readvancing it for each wedge pressure determination significantly reduces the risk of catheter-induced pulmonary hemorrhage in this model.

Physiological desensitization of carbohydrate permeases and adenylate cyclase to regulation by the phosphoenolpyruvate:sugar phosphotransferase system in Escherichia coli and Salmonella typhimurium. Involvement of adenosine cyclic 3',5'-phosphate and inducer.

Adenylate cyclase and a number of carbohydrate transport systems are subject to regulation by the phosphoenolpyruvate:sugar phosphotransferase system. These sensitive carbohydrate transport systems are desensitized to regulation by the phosphotransferase system, and adenylate cyclase is deactivated when cells are grown in medium containing cyclic AMP. These effects are specific for cyclic AMP and are potentiated by the genetic loss of cyclic AMP phosphodiesterase. Inclusion in the growth medium of an inducer of a sensitive transport system also promotes desensitization of that particular transport system. Inducer-promoted desensitization is specific for the particular target transport system, while cyclic AMP-promoted desensitization is general and affects several systems. Desensitization of the permeases to regulation, and inactivation of adenylate cyclase, are slow processes which are blocked by chloramphenicol and are therefore presumably dependent on protein synthesis. Several sugar substrates of the phosphotransferase system are capable of regulating the sensitive carbohydrate transport systems. The evidence suggests that desensitization to this regulation does not result from a direct effect on the functioning of Enzyme I, a small heat-stable protein of the phosphotransferase system, HPr, or an Enzyme II of the phosphotransferase system, but specifically uncouples the permease systems from regulation.