Oxygen consumption and carbon dioxide production during liquid ventilation

Liquid ventilation with perfluorocarbon (PFCV) has advantages over conventional gas ventilation (GV) in premature and lung-injured newborn animals. Indirect calorimetric measurement of both oxygen consumption (VO2) and carbon dioxide production (VCO2) during PFCV has not been previously performed. In addition, comparison to indirect calorimetric measurement of VO2 and VCO2 during GV has not been evaluated. Ten fasted normal cats weighing 2.6 to 3.9 kg were anesthetized with pentobarbital and pancuronium. Tracheostomy was performed. Gas exchange was measured across the native lung during GV and across the membrane lung of the liquid ventilator during PFCV. VO2 was measured using a modification of a previously described, indirect, closed-circuit, volumetric technique. VCO2 was analyzed by capnographic assay of the mixed-expired closed-circuit air. The VCO2/VO2 ratio (RQ) was calculated. There was no change in VO2, VCO2, or RQ during PFCV when compared with GV (VO2: GV = 5.7 +/- 0.3 mL/kg/min, PFCV = 5.6 +/- 0.5 mL/kg/min [P = NS]; VCO2: GV = 4.9 +/- 1.1 mL/kg/min, PFCV = 4.8 +/- 0.9 mL/kg/min [P = NS]; RQ: GV = 0.85 +/- 0.21, PFCV = 0.86 +/- 0.21 [P = NS]). During GV the PaO2 was higher than during PFCV (PaO2: GV = 335 +/- 70 mm Hg, PFCV = 267 +/- 83 mm Hg [P = .04]), as is expected because of the relative reduction in the inspiratory PiO2 of the perfluorocarbon during liquid ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term memory of acute postsurgical pain

The long-term memory of acute postoperative pain intensity was evaluated in a population of patients who had undergone the removal of impacted third molar teeth. The results suggest a positive correlation between experienced and remembered intensities of postsurgical pain for up to 3 years after surgery. They also suggest that males and females do not differ significantly in their reports of postsurgical pain intensity, nor do they differ significantly in their memories of pain intensity. Pain recall using verbal pain descriptors was more reliable than recall with visual analog scales. Patient reports of intensity of past postsurgical acute pain, particularly those reports obtained with verbal descriptors, may be useful in the planning of treatment and in the selection and evaluation of analgesic regimens.

Digital image display station performance requirements based on physician experience with a prototype system

The authors report on observations of and interviews with physicians using a prototype digital image display and reporting station. While the users generally agree that image quality is clinically satisfactory, they are unanimous in their opinion that improvements in the man-machine interface are required before case review by this mechanism is clinically acceptable in a production environment. A model image and information user interface is presented. It was developed in answer to the needs of radiologists and referring physicians operating in the imaging department of a community acute-care facility. In such an environment images and related information must be communicated quickly and often simultaneously to different parts of the department and hospital. The user interface with the management system and the management system itself must address the varied functions and the needs of both the medical and clerical staff. Image enhancement processes, for example, must be restricted to those that quickly provide significantly more perceivable diagnostic information. Little-used processes that may occupy significant portions of the display and the console's computing power must be trimmed or eliminated.