17 Jan 12
Posted in Anesthesia at 1:50 by Laci
By K Hirota and D Lambert
Br. J. Anaesth. (2011) 107 (2): 123-126.
In 1996, we published an editorial ‘Ketamine, mechanism(s) of action and unusual clinical uses’ in the British Journal of Anaesthesia. In that editorial, we described the pharmacology of ketamine including bronchodilator, anti-shock, and neuroprotective actions along with some unusual clinical applications. The editorial has been cited more than 130 times in total with around 10 citations every year, which implies that ketamine is still of interest to a wide audience. However, as ketamine anaesthesia is associated with cardiovascular hyperdynamics and disturbing emergence reactions, this agent is often avoided, despite the ease with which these adverse reactions can be prevented by pre-administration, co-administration of sedatives, or both such as benzodiazepines, propofol, dexmedetomidine, or droperidol.
In the past 15 yr, ketamine has been reported to possess several new clinically beneficial properties such as potentiation of opioid analgesia, prevention of opioid-induced acute tolerance and spinal ischaemia, anti-inflammatory actions, preventive effects on recall and awareness during general anaesthesia, and anti-tumour actions. In this ‘update’ editorial, we have focused on these potential clinical advantages of ketamine.
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16 Jan 12
Posted in ScvO2, Sepsis at 1:01 by Laci
By M Varpula, S Karlsson, E Ruokonen, V Pettilä
Intensive Care Med (2006) 32:1336–1343
Central venous oxygen saturation (ScvO2) in initial resuscitation is included in the Surviving Sepsis Campaign guidelines. ScvO2 monitoring has also been suggested to be comparable to mixed venous oxygen saturation (SvO2) for clinical purposes. The aim of our study was to assess the correlation and agreement of ScvO2 and SvO2 and compare ScvO2?SvO2 difference to lactate, oxygen-derived and hemodynamic parameters in early septic shock in ICU after initial resuscitation.
Design and setting
Prospective clinical study with 16 patients with septic shock at two university hospital ICUs. A dose of norepinephrine over 0.1ug/kg/min was required for inclusion.
Measurements and results
Five paired ScvO2 and SvO2 samples at 6-h intervals, altogether 72 samples, were collected during 24 h. The mean SvO2 was below the mean ScvO2 at all time points. Bias of difference was 4.2% and 95% limits of agreement ranged from 8.1% to 16.5%. The difference correlated significantly to CI and DO2.
Conclusion
The difference between paired ScvO2 and SvO2 varies highly. Therefore, SvO2 may not be estimated on the basis of ScvO2 in treatment of septic shock after resuscitation period in ICU.
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15 Jan 12
Posted in Pre-operatie evaluation at 2:48 by Laci
By B M Biccard and R N Rodseth
Br. J. Anaesth 2011;107:133-143
Cardiovascular risk prediction using clinical risk factors is integral to both the European and the American algorithms for preoperative cardiac risk assessment and perioperative management for non-cardiac surgery. We have reviewed these risk factors and their ability to guide clinical decision making. We examine their limitations and attempt to identify factors which may improve their performance when used for clinical risk stratification. To improve the performance of the clinical risk factors, it is necessary to create uniformity in the definitions of both cardiovascular outcomes and the clinical risk factors. The risk factors selected should reflect the degree of organ dysfunction rather than a historical diagnosis. Parsimonious model design should be applied, making use of a minimal number of continuous variables rather than creating overfitted models. The inclusion of age in the model may assist partly in controlling for the duration of risk factor exposure. Risk assignment should occur throughout the perioperative period and the risk factors chosen for model inclusion should vary depending on when the assignment occurs (before operation, intraoperatively, or after operation).
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14 Jan 12
Posted in Anesthesia, Obesity at 1:01 by Laci
By A S Eichenberger, S Proietti, S Wicky, P Frascarolo, M Suter, D R Spahn, L Magnusson
Anesth Analg 2002;95:1788-1792
Perturbation of respiratory mechanics produced by general anesthesia and surgery is more pronounced in morbidly obese (MO) patients. Because general anesthesia induces pulmonary atelectasis in nonobese patients, we hypothesized that atelectasis formation would be particularly significant in MO patients. We investigated the importance and resorption of atelectasis after general anesthesia in MO and nonobese patients. Twenty MO patients were anesthetized for laparoscopic gastroplasty and 10 nonobese patients for laparoscopic cholecystectomy. We assessed pulmonary atelectasis by computed tomography at three different periods: before the induction of general anesthesia, immediately after tracheal extubation, and 24 h later. Already before the induction of anesthesia, MO patients had more atelectasis, expressed in the percentage of the total lung area, than nonobese patients (2.1% versus 1.0%, respectively; P < 0.01). After tracheal extubation, atelectasis had increased in both groups but remained significantly more so in the MO group (7.6% for MO patients versus 2.8% for the nonobese; P < 0.05). Twenty-four hours later, the amount of atelectasis remained unchanged in the MO patients, but we observed a complete resorption in nonobese patients (9.7% versus 1.9%, respectively; P < 0.01). General anesthesia in MO patients generated much more atelectasis than in nonobese patients. Moreover, atelectasis remained unchanged for at least 24 h in MO patients, whereas atelectasis disappeared in the nonobese.
Implications
We compared the resolution over time of pulmonary atelectasis after a laparoscopic procedure by performing computed tomography scans in two different groups of patients: 1 group had 10 nonobese patients, and in the other group there were 20 morbidly obese patients.
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