[Peripheral analgesic effect of intra-articularly applied clonidine]. / Periphere analgetische Wirkung durch intraartikulär verabreichtes Clonidin.

BACKGROUND AND AIM: Clonidine applied intra-articularly into the knee joint has a peripheral analgesic effect. We examined intra-articularly injected clonidine to determine whether resorption with a measurable systemic concentration could be detected. METHODS: A randomised, placebo-controlled double-blind study was carried out on patients undergoing knee arthroscopies. The 69 patients were randomised into three groups: group 1 received 150 ug clonidine intra-articularly, group two 150 ug clonidine intravenously and group three a placebo. Postoperative pain therapy was carried out with i.v. morphine hydrochloride. Pain scores and side-effects were documented for 24 h. RESULTS: There were no significant differences between the three groups in demographics, duration of operation, duration of anaesthesia, diagnoses or type of operation. The pain score at rest was significantly lower in group 1. In the first 20 min, the systemic concentration of clonidine was significantly higher in the intravenous group than in the intra-articular group. CONCLUSION: Intra-articular clonidine has a postoperative analgesic effect after knee arthroscopies due to a peripheral action.

Transesophageal echocardiographic assessment of right heart hemodynamics during high-frequency jet ventilation.

STUDY OBJECTIVE: To evaluate right ventricular dimensions and function by echocardiography in anesthetized patients during superimposed high-frequency jet ventilation (HFJV). DESIGN: Prospective clinical study. SETTING: University hospital operating room. PATIENTS: 20 ASA physical status I patients undergoing elective minor otorhinolaryngological surgery, and undergoing conventional mechanical ventilation with subsequent superimposed HFJV. INTERVENTIONS: Two-dimensional transesophageal echocardiography with a 5-MHz multiplane transducer to determine right ventricular dimensions and function from a mid-esophageal view. Insertion of a radial artery catheter for monitoring blood pressure and blood gases. MEASUREMENTS AND MAIN RESULTS: Heart rate, mean arterial blood pressure, and right ventricular end-diastolic and end-systolic volumes determined by echocardiography, stroke volume, and ejection fraction. Measurements were performed after 10 minutes of conventional positive pressure ventilation (control) and after 10 minutes of subsequent superimposed HFJV at similar peak and positive end-expiratory airway pressures. Right ventricular systolic and diastolic volumes, stroke volume, and ejection fraction did not reveal statistical significant differences after transition to HFJV. Interventricular septum did not show any abnormalities in motion. In contrast, interatrial septum demonstrated momentary mid-systolic bows toward the left atrium in 9 of 17 patients (53%) during conventional ventilation, but in 15 of 17 patients (88%) during jet ventilation. Heart rate and mean arterial blood pressure remained unchanged, but arterial oxygen tension values were higher and arterial carbon dioxide tension values lower during HFJV. CONCLUSION: Transesophageal echocardiographic evaluation of right heart hemodynamics did not show any significant difference after transition of ventilation to superimposed HFJV applying similar airway pressures. Furthermore, superimposed HFJV was safe and effective, it improved oxygenation, and it facilitated carbon dioxide elimination.