24 Oct 07
Posted in Critical Care, Mechanical ventilation at 17:49 by Laci
By A M Machata, U M Illievich, B Gustorff, C Gonano, K Fäßler, C K Spiss
Anaesthesia 2007;62:796-801
We assessed the minimal remifentanil dosage required for tracheal tube tolerance in awake and spontaneously breathing patients after major abdominal surgery. Forty postoperative patients received remifentanil 0.1 μg.kg-1.min, which was reduced in steps of 0.025 μg.kg-1.min every 30 min. Respiratory response subscore of comfort scale (CSRR), Ramsay sedation scale (RSS), visual analogue scale (VAS), respiratory rate, and minute ventilation were recorded. Spontaneous respiration with no or little response to ventilation (CSRR 2) in co-operative, oriented and tranquil patients (RSS 2) was defined as the main outcome and study endpoint. Thirty-one patients (77.5%) reached a CSRR 2 and RSS 2 with remifentanil 0.025 μg.kg-1.min and nine patients (22.5%) required remifentanil 0.05 μg.kg-1.min. Analgesia was sufficient in all patients (VAS = 30). Remifentanil 0.025−0.05 μg.kg-1.min achieves satisfactory tracheal tube tolerance in awake and spontaneously breathing patients.
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Posted in Critical Care, Monitoring at 17:46 by Laci
By R B P de Wilde, J J Schreuder, P C M van den Berg, J R C Jansen
Anaesthesia 2007;62:760–768
The bias, precision and tracking ability of five different pulse contour methods were evaluated by simultaneous comparison of cardiac output values from the conventional thermodilution technique (COtd). The five different pulse contour methods included in this study were: Wesseling’s method (cZ); the Modelflow method; the LiDCO system; the PiCCO system and a recently developed Hemac method. We studied 24 cardiac surgery patients undergoing uncomplicated coronary artery bypass grafting. In each patient, the first series of COtd was used to calibrate the five pulse contour methods. In all, 199 series of measurements were accepted by all methods and included in the study. COtd ranged from 2.14 to 7.55 l.min-1, with a mean of 4.81 l.min-1. Bland-Altman analysis showed the following bias and limits of agreement: cZ, 0.23 and − 0.80 to 1.26 l.min-1; Modelflow, 0.00 and − 0.74 to 0.74 l.min-1; LiDCO, – 0.17 and − 1.55 to 1.20 l.min-1; PiCCO, 0.14 and − 1.60 to 1.89 l.min-1; and Hemac, 0.06 and − 0.81 to 0.93 l.min-1. Changes in cardiac output larger than 0.5 l.min-1 (10%) were correctly followed by the Modelflow and the Hemac method in 96% of cases. In this group of subjects, without congestive heart failure, with normal heart rhythm and reasonable peripheral circulation, the best results in absolute values as well as in tracking changes in cardiac output were measured using the Modelflow and Hemac pulse contour methods, based on non-linear three-element Windkessel models.
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13 Oct 07
Posted in Anesthesia, Fluid management at 15:39 by Laci
By K Holte, N B Foss, J Andersen, L Valentiner, C Lund, P Bie and H Kehlet
BJA 2007;99:500-508
Evidence-based guidelines on optimal perioperative fluid management have not been established, and recent randomized trials in major abdominal surgery suggest that large amounts of fluid may increase morbidity and hospital stay. However, no information is available on detailed functional outcomes or with fast-track surgery. Therefore, we investigated the effects of two regimens of intraoperative fluids with physiological recovery as the primary outcome measure after fast-track colonic surgery.
Methods
In a double-blind study, 32 ASA I–III patients undergoing elective colonic surgery were randomized to ‘restrictive’ (Group 1) or ‘liberal’ (Group 2) perioperative fluid administration. Fluid algorithms were based on fixed rates of crystalloid infusions and a standardized volume of colloid. Pulmonary function (spirometry) was the primary outcome measure, with secondary outcomes of exercise capacity (submaximal exercise test), orthostatic tolerance, cardiovascular hormonal responses, postoperative ileus (transit of radio-opaque markers), postoperative nocturnal hypoxaemia, and overall recovery within a well-defined multimodal, fast-track recovery programme. Hospital stay and complications were also noted.
Results
‘Restrictive’ (median 1640 ml, range 935–2250 ml) compared with ‘liberal’ fluid administration (median 5050 ml, range 3563–8050 ml) led to significant improvement in pulmonary function and postoperative hypoxaemia. In contrast, we found significantly reduced concentrations of cardiovascularly active hormones (renin, aldosterone, and angiotensin II) in Group 2. The number of patients with complications was not significantly different between the groups (1 vs 6 patients, P = 0.08).
Conclusions
A ‘liberal’ fluid regimen led to a transient improvement in pulmonary function and postoperative hypoxaemia but no other differences in all-over physiological recovery compared with a ‘restrictive’ fluid regimen after fast-track colonic surgery. Since morbidity tended to be increased with the ‘restrictive’ fluid regimen, future studies should focus on the effect of individualized ‘goal-directed’ fluid administration strategies rather than fixed fluid amounts on postoperative outcome.
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Posted in Anesthesia at 11:52 by Laci
By E Marret, C Remy, F Bonnet F
Br J Surg. 2007;94:665-73
Epidural analgesia (EA) with local anaesthetic is considered to play a key role after colorectal surgery. However, its effect on postoperative recovery is still a matter of debate.
Methodes
A systematic review of randomized controlled trials comparing postoperative EA and parenteral opioid analgesia after colorectal surgery was performed. The effect on postoperative recovery was evaluated in terms of length of hospital stay, pain intensity, duration of postoperative ileus, incidence of postoperative complications and side-effects.
Results
Sixteen trials published between 1987 and 2005 were included. EA significantly reduced pain scores and duration of ileus (weighted mean difference – 1.55 (95 per cent confidence interval (c.i.) – 2.27 to – 0.84) days). On the other hand, it was associated with a significant increase in the incidence of pruritus (odds ratio (OR) 4.8 (95 per cent c.i. 1.3 to 17.0)), urinary retention (OR 4.3 (1.2 to 15.9)) and arterial hypotension (OR 13.5 (4.0 to 57.7)). EA did not influence duration of hospital stay.
Conclusion
Despite improved analgesia and a decrease in ileus, EA has some adverse effects and does not shorten the duration of hospital stay after colorectal surgery.
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