Alain Remy

Feasibility of Automated Propofol Sedation for Transcatheter Aortic Valve Implantation: A Pilot Study.

BACKGROUND: Recently, several trials have shown that closed-loop sedation is feasible. No study has used automated sedation in extremely frail patients, such as those scheduled for transcatheter aortic valve implantation (TAVI). We developed and tested a novel automated sedation system for this kind of population and surgery. The system integrates a decision support system that detects respiratory and hemodynamic events via smart alarms, which provide pertinent/related clinical suggestions and treatment options. The main objective was the feasibility of closed-loop sedation, defined as successful automated sedation without manual override. Secondary qualitative observations were clinical and controller performance. METHODS: Twenty patients scheduled for elective TAVI were enrolled. Sedation was administered via a closed-loop delivery system designed for propofol. The clinical performance of sedation was the efficacy to maintain a bispectral index (BIS) of 65. To evaluate the sedation performance, BIS values were stratified into 4 categories: excellent, very good, good, and inadequate sedation control, defined as BIS values within 10%, ranging from 11% to 20%, ranging from 21% to 30%, or >30% from the target value, respectively. The controller performance was calculated using Varvel parameters. Critical respiratory and hemodynamic events were documented. The former was defined as peripheral oxygen saturation <92% and/or respiratory rate <8/min, whereas the latter was considered a mean arterial pressure <60 mm Hg and/or heart rate <40 bpm. RESULTS: Automated sedation was successful in 19 patients undergoing TAVI. One patient was excluded from the final analysis because of conversion to general anesthesia. The secondary observations revealed that the clinical performance allowed an excellent to good control during 69% (99% confidence interval, 53%–77%; interquartile range, 59%–79%) of the sedation time. Fifteen patients presented critical respiratory episodes, with a median of 3 events per hour of sedation. Six patients presented critical hemodynamic episodes, with a median of 2 events per hour of procedure. CONCLUSIONS: The automated closed-loop sedation system tested could be used successfully for patients scheduled for a TAVI procedure. The results showed a satisfactory clinical performance of sedation control.

New markers for early detection of acute kidney injury after transcatheter aortic valve implantation

BACKGROUND Acute kidney injury (AKI) is a frequent complication after a transcatheter aortic valve implantation (TAVI). Biomarkers such as urinary G1 cell cycle arrest proteins (TIMP-2 and IGFBP7) and sonographic evaluation (Doppler Renal Resistive Index [RRI]) have been advocated to predict AKI at an early stage after a TAVI-procedure. The primary aim was to determine the predictive value of these markers to detect AKI after a TAVI-procedure at an early phase. PATIENTS AND METHODS In a prospective observational study, 62 consecutive patients were scheduled for a TAVI. AKI was assessed based on the KDIGO criteria. Biomarkers and RRI were measured concomitantly before TAVI, at the first micturition post-implantation and the first micturition on the morning after the procedure. RESULTS Twenty-two patients (35%) developed AKI. On the first day after the TAVI-procedure, urinary TIMP-2 and IGFBP7 concentrations increased significantly in patients who developed AKI (0.1, [interquartile] [0.1-0.35] to 0.40 [0.10-1.00] vs. 0.2 [0.1-0.5] to 0.10 [0.10-0.20], P=0.012) with an area under the receiver-operating characteristic curve of 0.71 [0.55-0.83]. Sensitivity was 0.57 and specificity was 0.83 for a cut-off value of 0.35. No significant increases in RRI were found in patients who developed AKI. CONCLUSIONS Based on the current guidelines for the diagnosis of AKI, the urinary proteins TIMP-2 and IGFBP7 do not detect AKI at an early stage accurately in patients undergoing a TAVI-procedure.

The Feasibility of a Completely Automated Total IV Anesthesia Drug Delivery System for Cardiac Surgery.

BACKGROUND:In this pilot study, we tested a novel automatic anesthesia system for closed-loop administration of IV anesthesia drugs for cardiac surgical procedures with cardiopulmonary bypass. This anesthesia drug delivery robot integrates all 3 components of general anesthesia: hypnosis, analgesia, and muscle relaxation. METHODS:Twenty patients scheduled for elective cardiac surgery with cardiopulmonary bypass were enrolled. Propofol, remifentanil, and rocuronium were administered using closed-loop feedback control. The main objective was the feasibility of closed-loop anesthesia defined as successful automated cardiac anesthesia without manual override by the attending anesthesiologist. Secondary qualitative observations were clinical and controller performances. The clinical performance of hypnosis control was the efficacy to maintain a bispectral index (BIS) of 45. To evaluate the hypnosis performance, BIS values were stratified into 4 categories: “excellent,” “good,” “poor,” and “inadequate” hypnosis control defined as BIS values within 10%, ranging from 11% to 20%, ranging from 21% to 30%, or >30% of the target value, respectively. The clinical performance of analgesia was the efficacy to maintain NociMap values close to 0. The analgesia performance was assessed classifying the NociMap values in 3 pain control groups: −33 to +33 representing excellent pain control, −34 to −66 and +34 to +66 representing good pain control, and −67 to −100 and +67 to +100 representing insufficient pain control. The controller performance was calculated using the Varvel parameters. RESULTS:Robotic anesthesia was successful in 16 patients, which is equivalent to 80% (97.5% confidence interval [CI], 53%–95%) of the patients undergoing cardiac surgery. Four patients were excluded from the final analysis because of technical problems with the automated anesthesia delivery system. The secondary qualitative observations revealed that the clinical performance of hypnosis allowed an excellent and good control during 70% (97.5% CI, 63%–76%) of maintenance time and an insufficient clinical performance of analgesia for only 3% (97.5% CI, 1%–6%) of maintenance time. CONCLUSIONS:The completely automated closed-loop system tested in this investigation could be used successfully and safely for cardiac surgery necessitating cardiopulmonary bypass. The results of the present trial showed satisfactory clinical performance of anesthesia control.

A combined approach for the early recognition of acute kidney injury after adult cardiac surgery

BACKGROUND Cardiac surgery-associated acute kidney injury (CSA-AKI) is a frequent complication. The current criteria to detect CSA-AKI rise only when organic dysfunction has occurred. The Doppler Renal Resistive Index (RRI) and the urinary G1 cell cycle arrest proteins (TIMP-2 and IGFBP7) have been advocated to predict CSA-AKI at an early stage after cardiac surgery. The primary objective was to determine the predictive value of these new markers to detect CSA-AKI after elective heart surgery in patients at risk to develop AKI. METHODS In a prospective observational trial, we studied 50 patients scheduled for elective on-pump heart surgery at high risk for CSA-AKI. The primary outcome was the incidence of AKI according to the KDIGO criteria recording the urine output every hour until ICU discharge and measuring the serum creatinine levels on each postoperative day until the post-procedure peak values were reached or until the 7th postoperative day. The RRI and the urinary proteins [TIMP-2]*[IGFBP7] were measured concomitantly: before surgery, 1hour (H1), 4-hour (H4), 12-hour (H12), and 24-hour (H24) after surgery. RESULTS Thirty-seven patients (74%) developed CSA-AKI. Urinary [TIMP-2]*[IGFBP7] at H12 were significantly higher in patients that developed AKI (0.62, [interquartile] [0.20-1.18] vs. 0.30 [0.07-0.47] P=0.044) with an area under the receiver-operating characteristic curve of 0.69 [0.53-0.84]. The best sensitivity (65%) and specificity (62%) was achieved for a cutoff value of 0.3 (ng.mL-1)2.1000-1. The H12 time-point was the only in which the RRI values measured showed a trend toward statistical significance in patients that developed AKI (0.72 (Standard deviation)±(0.06) vs. 0.68±(0.07) P=0.065). The combination of the two markers ([TIMP-2]*[IGFBP7]+RRI) at H12 showed an increased performance of the accuracy with an area under the receiver-operating characteristic curve of 0.78 [0.62-0.93]. CONCLUSIONS In a population at risk of developing CSA-AKI, neither the RRI nor urinary [TIMP-2]*[IGFBP7] detect CSA-AKI occurring in the first post-operative week within the first 24 postoperative hours.