ABSTRACT
OBJECTIVES: Preoperative carbohydrate administration attenuates insulin resistance. We studied effects of preoperative oral carbohydrate loading in elderly patients undergoing coronary artery bypass grafting. DESIGN: Eighteen patients were assigned either to get a carbohydrate drink or to be controls. Perioperatively, glucose was administered. A gastric emptying test was performed. Glucose and insulin concentrations were measured. Levels of glucose, insulin and stress hormones were studied pre-, per- and postoperatively. RESULTS AND DISCUSSION: Preoperative carbohydrate loading did not affect stress hormones. Gastric residual after the carbohydrate drink was 11+/-3% (mean+/-SEM). Glucose concentration was lower before anaesthesia induction in the carbohydrate group, possibly due to increased insulin release. Insulin levels differed at baseline, induction and day six. All patients returned to baseline on day six. CONCLUSIONS: The study group was insulin resistant on postoperative day one and two. The effects were explainable by the traumatic stress response. No adverse effect was noted from the carbohydrate drink. If glucose is administered intravenously during surgery, there is no obvious advantage of preoperative carbohydrate loading on insulin resistance or stress hormone response.
Subject(s)
Coronary Artery Bypass/adverse effects , Dietary Carbohydrates/therapeutic use , Insulin Resistance , Postoperative Complications/prevention & control , Preoperative Care/methods , Age Factors , Aged , Aged, 80 and over , Carbohydrate Metabolism , Chemoprevention , Dietary Carbohydrates/administration & dosage , Female , Gastric Emptying , Humans , Male , Nutritional Status , Prospective Studies , Time FactorsABSTRACT
STUDY OBJECTIVE: The validation of electrical impedance tomography (EIT) for measuring regional ventilation distribution by comparing it with single photon emission CT (SPECT) scanning. DESIGN: Randomized, prospective animal study. SETTINGS: Animal laboratories and nuclear medicine laboratories at a university hospital. PARTICIPANTS: Twelve anesthetized and mechanically ventilated pigs. INTERVENTIONS: Lung injury was induced by central venous injection of oleic acid. Then pigs were randomized to pressure-controlled mechanical ventilation, airway pressure-release ventilation, or spontaneous breathing. MEASUREMENTS AND RESULTS: Ventilation distribution was assessed by EIT using cross-sectional electrotomographic measurements of the thorax, and simultaneously by single SPECT scanning with the inhalation of (99m)Tc-labeled carbon particles. For both methods, the evaluation of ventilation distribution was performed in the same transverse slice that was approximately 4 cm in thickness. The transverse slice then was divided into 20 coronal segments (going from the sternum to the spine). We compared the percentage of ventilation in each segment, normalized to the entire ventilation in the observed slice. Our data showed an excellent linear correlation between the ventilation distribution measured by SPECT scanning and EIT according to the following equation: y = 0.82x + 0.7 (R(2) = 0.92; range, 0.86 to 0.97). CONCLUSION: Based on these data, EIT seems to allow, at least in comparable states of lung injury, real-time monitoring of regional ventilation distribution at the bedside.
