Browsing by keyword "Isoflurane"
Now showing items 1-4 of 4
-
Cisatracurium in "weakening doses" assists in weaning from sedation and withdrawal following extended use of inhaled isofluraneOBJECTIVE: Isoflurane was used to treat a patient with status asthmaticus refractive to standard therapeutic measures. The patient developed a significant withdrawal syndrome when the isoflurane was weaned. A case is reported here where this withdrawal syndrome was treated successfully by using a weakening dose neuromuscular blockade with cisatracurium. DESIGN: Case report. SETTING: Pediatric critical care unit. PATIENT: A 4-yr-old girl with severe reactive airways disease. INTERVENTIONS: The use of weakening doses of cisatracurium to assist in weaning from mechanical ventilation in the setting of withdrawal symptoms following the extended use of inhaled isoflurane. MEASUREMENTS AND MAIN RESULTS: Despite treatment with mechanical ventilation, intravenous corticosteroids, and bronchodilators for status asthmaticus, the patient required inhaled isoflurane. She became tolerant to isoflurane over an extended period of time; her tolerance was associated with a specific withdrawal syndrome, with the development of choreoathetoid movements resulting in poor pulmonary coordination and agitation. Conventional medical treatment of withdrawal failed. Finally, by using an infusion of cisatracurium at weakening doses to assist in the control of these choreoathetoid movements, the isoflurane and ventilator support were weaned. CONCLUSIONS: Weakening doses of cisatracurium may be used safely to control unpleasant motor symptoms secondary to tolerance of isoflurane. This may have a use in other circumstances where agitation in mechanically ventilated patients is not due to pain or anxiety.
-
Effects of Volatile Anesthetic Choice on Hospital Length-of-stay: A Retrospective Study and a Prospective TrialBACKGROUND:: Volatile anesthetic prices differ substantially. But differences in drug-acquisition cost would be inconsequential if hospitalization was prolonged by more soluble anesthetics. The authors tested the hypothesis that the duration of hospitalization is prolonged with isoflurane anesthesia. METHODS:: Initially, the authors queried their electronic records and used propensity matching to generate homogeneous sets of adults having inpatient noncardiac surgery who were given desflurane, sevoflurane, and isoflurane. The authors then conducted a prospective alternating intervention trial in which adults (mostly having colorectal surgery) were assigned to isoflurane or sevoflurane, based on protocol. RESULTS:: In the retrospective analysis, the authors identified 3,488 triplets matched on isoflurane, desflurane, or sevoflurane from among 43,352 adults. The adjusted geometric mean (95% CI) hospital length-of-stay for the isoflurane cases was 2.76 days (2.69-2.83); this was longer than that observed for both desflurane (2.56 [2.50-2.63]; P < 0.001) and sevoflurane (2.49 [2.43-2.56]; P < 0.0001). In the prospective trial (N = 1,584 operations), no difference was found; the adjusted ratio of means (95% CI) of hospital length-of-stay in patients receiving isoflurane versus sevoflurane was 0.98 (0.88-1.10), P = 0.77, with adjusted geometric means (95% CI) estimated at 4.1 (3.8-4.4) and 4.2 days (3.8-.5), respectively. CONCLUSIONS:: Results of the propensity-matched retrospective analysis suggested that avoiding isoflurane significantly reduced the duration of hospitalization. In contrast, length-of-stay was comparable in our prospective trial. Volatile anesthetic choice should not be based on concerns about the duration of hospitalization. These studies illustrate the importance of following even the best retrospective analysis with a prospective trial.
-
Imaging oxygen consumption in forepaw somatosensory stimulation in rats under isoflurane anesthesiaThe cerebral metabolic rate of oxygen (CMRO2) was dynamically evaluated on a pixel-by-pixel basis in isoflurane-anesthetized and spontaneously breathing rats following graded electrical somatosensory forepaw stimulations (4, 6, and 8 mA). In contrast to alpha-chloralose, which is the most widely used anesthetic in forepaw-stimulation fMRI studies of rats under mechanical ventilation, isoflurane (1.1-1.2%) provided a stable anesthesia level over a prolonged period, without the need to adjust the ventilation volume/rate or sample blood gases. Combined cerebral blood flow signals (CBF) and blood oxygenation level-dependent (BOLD) fMRI signals were simultaneously measured with the use of a multislice continuous arterial spin labeling (CASL) technique (two-coil setup). CMRO2 was calculated using the biophysical BOLD model of Ogawa et al. (Proc Natl Acad Sci USA 1992;89:5951-5955). The stimulus-evoked BOLD percent changes at 4, 6, and 8 A were, respectively, 0.5% +/- 0.2%, 1.4% +/- 0.3%, and 2.0% +/- 0.3% (mean +/- SD, N = 6). The CBF percent changes were 23% +/- 6%, 58% +/- 9%, and 87% +/- 14%. The CMRO2 percent changes were 14% +/- 4%, 24% +/- 6%, and 43% +/- 11%. BOLD, CBF, and CMRO2 activations were localized to the forepaw somatosensory cortices without evidence of plateau for oxygen consumption, indicative of partial coupling of CBF and CMRO2. This study describes a useful forepaw-stimulation model for fMRI, and demonstrate that CMRO2 changes can be dynamically imaged on a pixel-by-pixel basis in a single setting with high spatiotemporal resolution.
-
Isoflurane for life-threatening bronchospasm: a 15-year single-center experienceBACKGROUND: Children with severe bronchospasm requiring mechanical ventilation may become refractory to conventional therapy. In these critically ill patients, isoflurane is an inhaled anesthetic agent available in some centers to treat bronchospasm. We hypothesized that isoflurane is safe and would lead to improved gas exchange in children with life-threatening bronchospasm refractory to conventional therapy. METHODS: A retrospective review was conducted and included mechanically ventilated children treated with isoflurane in a quaternary pediatric ICU for life-threatening bronchospasm, from 1993 to 2007. Demographic, blood gas, ventilator, and outcome data were collected. RESULTS: Thirty-one patients, with a mean age of 9.5 years (range 0.4-23 years) were treated with isoflurane, from 1993 to 2007. Mean time to initiation of isoflurane after intubation was 13 hours (0-120 h), and the mean maximum isoflurane dose was 1.1% (0.3-2.5%). Mean duration of isoflurane administration was 54.5 hours (range 1-181 h), with a total mean duration of mechanical ventilation of 252 hours (range 16-1,444 h). Isoflurane led to significant improvement in pH and P(CO(2)) within 4 hours of initiation (P ≤ .001). Complications during isoflurane administration included hypotension requiring vasoactive infusions in 24 (77%), arrhythmia in 3 (10%), neurologic side effects in 3 (10%), and pneumothorax in 1 (3%) patient. CONCLUSIONS: Isoflurane led to improvement in pH and P(CO(2)) within 4 hours in this series of mechanically ventilated patients with life-threatening bronchospasm. The majority of patients in this series developed hypotension, but there was a low incidence of other side effects related to isoflurane administration. Isoflurane appears to be an effective therapy in patients with life-threatening bronchospasm refractory to conventional therapy. However, further investigation is warranted, given the uncertain overall impact of isoflurane in this context.