Isoflurane, 0.5 minimum alveolar concentration administered through the precardiopulmonary bypass period, reduces postoperative dobutamine requirements of cardiac surgery patients: a randomized study.

OBJECTIVE: Cardioprotective properties have been shown with halogenated volatile agents. It was hypothesized that low-dose isoflurane administered before aortic cross-clamping may reduce the amount of dobutamine required to improve impaired postoperative cardiac function after various types of cardiac surgery. DESIGN: A prospective, randomized trial. SETTING: An anesthesia and intensive care unit, university hospital. PARTICIPANTS: Two hundred eighty cardiac surgery patients. INTERVENTIONS: All patients allocated to either isoflurane treatment (T) or no treatment (control group [C]) received total intravenous anesthesia. In the treatment group, isoflurane was administered at a 0.5 minimum alveolar concentration (MAC) from tracheal intubation to initiation of cardiopulmonary bypass (CPB). During weaning from CPB, dobutamine was introduced by using a hemodynamically driven decision tree. MEASUREMENTS AND MAIN RESULTS: The number of patients receiving dobutamine was comparable (66 v 78, p = 0.07, in T and C groups, respectively). The total amount of postoperative dobutamine indexed to patient weight, considered as the primary endpoint, was reduced in the isoflurane-treated group (4.2 +/- 8 v 7.2 +/- 15, p < 0.02, in T and C, respectively). Isoflurane was identified as an independent variable significantly (odds ratio [confidence interval]) influencing the total amount of postoperative dobutamine (0.53 [0.31-0.92], p < 0.02). Postoperative troponin I release at 20 hours was not affected by isoflurane treatment. CONCLUSIONS: This study revealed that exposure to 0.5 MAC isoflurane before CPB reduced the total amount of dobutamine required to normalize postoperative cardiac dysfunction in various types of cardiac surgical patients.

AlOH3-adjuvanted vaccine-induced macrophagic myofasciitis in rats is influenced by the genetic background.

Macrophagic myofasciitis (MMF) is a specific histopathologic lesion involved in the persistence for years of aluminum hydroxide [Al(OH)(3)] at the site of previous intramuscular (i.m.) injection. In order to study mechanisms involved persistence of MMF lesions, we set up an experimental model of MMF-lesion in Sprague-Dawley and Lewis rat, by i.m. injections of 10 microL of an Al(OH)(3)-adjuvanted vaccine. An evaluation carried out over a 12-month period disclosed significant shrinkage of MMF lesions with time. A radioisotopic study did not show significant aluminium uptake by Al(OH)(3)-loaded macrophages. A morphometric approach showed that Lewis rats with Th1-biased immunity had significantly smaller lesions than Sprague-Dawley rats with balanced Th1/Th2 immunity. Concluding, our results indicate that genetic determinatives of cytotoxic T-cell responses could interfere with the clearance process and condition the persistence of vaccine-induced MMF-lesions.

Clinical and hemodynamic performance of the 19-mm medtronic mosaic bioprosthesis.

BACKGROUND AND AIM OF THE STUDY: The Medtronic Mosaic valve (MMV) is a latest generation supra-annular stented porcine valve, which combines a low-profile stent, leaflet fixation at zero pressure in a predilated aortic root, and amino-oleic acid anti-mineralization treatment for improved hemodynamics and durability. A study was conducted to evaluate the clinical and hemodynamic performances of the MMV in patients with a small aortic root (19 mm aortic annulus). METHODS: Between 1998 and 2004, 81 consecutive patients (69 females, 12 males; mean age 78.0 +/- 5.5 years) underwent aortic valve replacement using the 19-mm MMV. Concomitant coronary artery bypass grafting was performed in 28 patients (29.2%), and mitral valve surgery in one patient (1.2%). RESULTS: The 30-day mortality rate was 9.9% (eight deaths). Postoperative actuarial survival estimates were 90.1 +/- 3.3%, 78.5 +/- 4.6% and 69.1 +/- 5.5% at one month, one year and two years, respectively. After a mean follow up of 2.7 +/- 1.9 years, no cases of structural dysfunction, non-structural dysfunction or valve thrombosis were noted. Four ischemic cerebral complications (2.0% per patient-year (pt-yr)), five bleeding complications (2.0%/pt-yr) and two prosthetic valve infections (1.0%/pt-yr) were observed. No reoperation on a MMV was performed. Postoperatively, the mean systolic gradient was 23.4 +/- 7.0 mmHg, and the effective orifice area (EOA) 1.06 +/- 0.33 cm2. Valve prosthesis-patient mismatch (VP-PM) was moderate (indexed EOA > 0.65 cm2/m2 and < or = 0.85 cm2/m2) in 40 patients (49.4%), and severe (indexed EOA < or = 0.65 cm2/m2) in 41 (50.6%). CONCLUSION: Although providing acceptable clinical results, implantation of the 19-mm MMV resulted in a high incidence of postoperative VP-PM. Hence, this valve should be reserved for patients in whom the projected indexed EOA calculated preoperatively is deemed acceptable, given the patient's clinical condition.

Intubating laryngeal mask airway in morbidly obese and lean patients: a comparative study.

BACKGROUND: The intubating laryngeal mask airway (ILMA) was designed using the characteristics of healthy-weight subjects but was shown to be an effective airway device in morbidly obese patients. The authors compared airway management quality in morbidly obese and lean patients with use of the ILMA. METHODS: Fifty morbidly obese and 50 lean patients (mean body mass indexes, 42 and 27 kg/m, respectively) were enrolled in this prospective study. After induction of general anesthesia, characteristics of airway management were judged on safety and efficiency parameters, including success rate at ventilation and intubation and airway management quality criteria, such as the number of patients who required adjustment maneuvers, the number of failed tracheal intubation attempts, the total duration of airway management, and an overall difficulty visual analog scale score. RESULTS: The ILMA was successfully inserted and adequate ventilation through the ILMA was achieved in all 100 patients. The success rates of tracheal intubation through the ILMA were similar in obese and lean patients (96% and 94%, respectively). The numbers of failed blind tracheal access attempts and patients who required airway-adjustment maneuvers were significantly reduced in obese patients as compared with lean patients. Four obese patients experienced transient episodes of oxygen desaturation (oxygen saturation < 90%) before adequate bag ventilation was established with the ILMA. CONCLUSION: The authors confirmed that the ILMA was an efficient airway device for airway management of both lean and obese patients. In the conditions of this study, the authors observed that airway management with the ILMA was simpler in obese patients as compared with lean patients.

Unanticipated difficult airway in anesthetized patients: prospective validation of a management algorithm.

BACKGROUND: Management strategies conceived to improve patient safety in anesthesia have rarely been assessed prospectively. The authors undertook a prospective evaluation of a predefined algorithm for unanticipated difficult airway management. METHODS: After a 2-month period of training in airway management, 41 anesthesiologists were asked to follow a predefined algorithm for management in the case of an unanticipated difficult airway. Two different scenarios were distinguished: "cannot intubate" and "cannot ventilate." The gum elastic bougie and the Intubating Laryngeal Mask Airway (ILMA) were proposed as the first and second steps in the case of impossible laryngoscope-assisted tracheal intubation, respectively. In the case of impossible ventilation or difficult ventilation, the IMLA was recommended, followed by percutaneous transtracheal jet ventilation. The patient's details, adherence rate to the algorithm, efficacy, and complications of airway management processes were recorded. RESULTS: Impossible ventilation never occurred during the 18-month study. One hundred cases of unexpected difficult airway were recorded (0.9%) among 11,257 intubations. Deviation from the algorithm was recorded in three cases, and two patients were wakened before any alternative intubation technique attempt. All remaining patients were successfully ventilated with either the facemask (89 of 95) or the ILMA (6 of 95). Six difficult-ventilation patients required the ILMA before completion of the first intubation step. Eighty patients were intubated with the gum elastic bougie, and 13 required a blind intubation through the ILMA. Two patients ventilated with the ILMA were never intubated. CONCLUSION: When applied in accordance with a predefined algorithm, the gum elastic bougie and the ILMA are effective to solve most problems occurring during unexpected difficult airway management.