Closed-loop coadministration of propofol and remifentanil guided by bispectral index: a randomized multicenter study.

BACKGROUND: We have developed a proportional-integral-derivative controller allowing the closed-loop coadministration of propofol and remifentanil, guided by a Bispectral Index (BIS) monitor, during induction and maintenance of general anesthesia. The controller was compared with manual target-controlled infusion. METHODS: In a multicenter study, 196 surgical patients were randomly assigned to dual closed-loop or manual administration of propofol and remifentanil. Comparison between groups was evaluated by calculating a global score that characterized the overall performance of the controller including the percentage of adequate anesthesia, defined as BIS between 40 and 60, the median absolute performance error, and wobble. Secondary outcomes included occurrence of burst suppression ratio, time to tracheal extubation, and drug consumption. RESULTS: Eighty-three patients assigned to dual-loop control and 84 patients assigned to manual control completed the study. The global score and the percentage of time with BIS between 40 and 60 were better in the dual-loop group (26 ± 11 vs 43 ± 40, P < 0.0001; 82% ± 12% vs 71% ± 19%, P < 0.0001). Overshoot (BIS <40), undershoot (BIS >60), and burst suppression ratio were all significantly less common in the dual-loop group. Modifications to the propofol and remifentanil infusions were more frequent, and adjustments smaller in the dual-loop group. Remifentanil consumption was greater (0.22 ± 0.07 vs 0.16 ± 0.07 µg · kg(-1) · min(-1); P < 0.0001) and the speed to tracheal extubation was shorter (10 ± 4 vs 11 ± 5 minutes; P = 0.02) in the dual-loop group. CONCLUSION: The controller allows the automated delivery of propofol and remifentanil and maintains BIS values in predetermined boundaries during general anesthesia better than manual administration.

Prevention of pulmonary complications after aortic surgery: evaluation of prophylactic noninvasive perioperative ventilation.

BACKGROUND: In 40% of the cases, pulmonary complications are encountered after aortic surgery in patients suffering from chronic obstructive broncho-pneumopathy (COBP). The factors aggravating the occurrence of these complications are cumulated tobacco addiction of ≥40 packets per year and surgery for aneurysm. The aim of our prospective study was to evaluate the effect of pre- and postoperative noninvasive ventilation (NIV) preparation on the respiratory function of patients presenting with high pulmonary risks. METHODS: Between September 2007 and May 2010, 30 patients were included in the present study. Inclusions criteria were male gender, patients suffering from COBP with tobacco addiction of ≥40 packets per year, and aortic surgery for aneurysm with or without occlusive lesions. In all, 14 of the 15 patients had effectively performed the preparation before and after surgery according to a fixed protocol (NIV group). We compared the respiratory rate complications and the mean hospital length of stay in intensive care with the non-NIV control group (15 patients). RESULTS: Mean age, severity of COBP according to the classification of the French Society for Pneumology, surgery duration, and blood losses were comparable between the two groups. Conversely, pulmonary complications were significantly lower in the NIV group (0/14 [0%] vs. 5/15 [33%], p = 0.004). Hospital length of stay in intensive care was shorter in the NIV group (2.5 vs. 6.5 days, p < 0.001). CONCLUSION: Preliminary results are encouraging, in favor of pulmonary preparation before aortic surgery with NIV at home, and carried on postoperatively in hospital for patients with COBP. These results prompt us to propose a multicenter study to validate these first observations.

Evaluation of financial burden following complications after major surgery in France: Potential return after perioperative goal-directed therapy.

OBJECTIVE: Perioperative goal-directed therapy (PGDT) has been demonstrated to improve postoperative outcomes and reduce the length of hospital stays. The objective of our analysis was to evaluate the cost of complications, derived from French hospital payments, and calculate the potential cost savings and length of hospital stay reductions. METHODS: The billing of 2388 patients who underwent scheduled high-risk surgery (i.e. major abdominal, gynaecologic, urological, vascular, and orthopaedic interventions) over three years was retrospectively collected from three French hospitals (one public-teaching, one public, and one private hospital). A relationship between mortality, length of hospital stays, cost/patient, and severity scores, based mainly on postoperative complications but also on preoperative clinical status, were analysed. Statistical analysis was performed using Student's t-tests or Wilcoxon tests. RESULTS: Our analyses determined that a severity score of 3 or 4 was associated with complications in 90% of cases and this represented 36% of patients who, compared with those with a score of 1 or 2, were associated with significantly increased costs (€ 8205±3335 to € 22,081±16,090; P<0.001, delta of € 13,876) and a prolonged length of hospital stay (mean of 10 to 27 days; P<0.001, delta of 17 days). According to estimates for complications avoided by PGDT, there was a projected reduction in average healthcare costs of between € 854 and € 1458 per patient and a reduction in total hospital bed days from 1755 to 4423 over three years. Based on French National data (47,000 high risk surgeries per year), the potential financial savings ranged from € 40M to € 68M, not including the costs of PGDT and its implementation. CONCLUSION: Our analysis demonstrates that patients with complications are significantly more expensive to care for than those without complications. In our model, it was projected that implementing PGDT during high-risk surgery may significantly reduce healthcare costs and the length of hospital stays in France while probably improving patient access to care and reducing waiting times for procedures.

Titration of propofol for anesthetic induction and maintenance guided by the bispectral index: closed-loop versus manual control: a prospective, randomized, multicenter study.

BACKGROUND: This report describes a closed-loop titration of propofol target control infusion based on a proportional-differential algorithm guided by the Bispectral Index (BIS) allowing induction and maintenance of general anesthesia and compares this to manual propofol target control infusion. METHODS: One hundred sixty-four patients scheduled to undergo elective minor or major surgery were prospectively randomized in a multicenter study into the closed-loop (n = 83) or manual target control infusion group (n = 81). The goal was to reach a BIS target of 50 during induction and to maintain it between 40 and 60 during maintenance. For both groups, remifentanil target control infusion was adjusted manually, and ventilation was without nitrous oxide. RESULTS: Closed-loop control was able to provide anesthesia induction and maintenance for all patients. During induction, propofol consumption was lower in the closed-loop group (1.4 +/- 0.5 vs. 1.8 +/- 0.6 mg/kg; P < 0.0001), but the duration was longer (320 +/- 125 vs. 271 +/- 120 s; P < 0.0002). Adequate anesthesia maintenance, defined as the BIS in the range of 40-60, was significantly higher in the closed-loop group (89 +/- 9 vs. 70 +/- 21%; P < 0.0001), with a decrease of the occurrence of BIS less than 40 (8 +/- 8 vs. 26 +/- 22%; P < 0.0001). Time from discontinuation of propofol infusion to tracheal extubation was shorter in the closed-loop group (7 +/- 4 vs. 10 +/- 7 min; P < 0.017). Unwanted somatic events and hemodynamic instability were similar. CONCLUSION: Automatic control of consciousness using the BIS is clinically feasible and outperforms manual control.