Relation between pretransplant magnesemia and the risk of new onset diabetes after transplantation within the first year of kidney transplantation.

BACKGROUND: New-onset diabetes after transplantation (NODAT) is a frequent condition associated with a poor outcome. In kidney transplantation, hypomagnesemia is a frequent posttransplant complication and has been associated with calcineurin inhibitors use. Previous studies have analyzed the relationship between posttransplant hypomagnesemia and the risk of NODAT and provided conflicting conclusions. We conducted an observational study to analyze the relationship between pretransplant magnesemia (Mg) and the risk of NODAT within the first year of kidney transplantation. METHODS: A cohort study was conducted to determine the risk conferred by pretransplant magnesium level on development of NODAT within 1 year posttransplant. First time kidney transplant recipients between January 2005 and December 2010 with more than 6 months of follow-up were included. Mg was measured within the 24 hours preceding kidney transplantation. NODAT was defined according to the American Diabetes Association criteria. RESULTS: Among the 154 patients analyzed, 28 (18.2%) developed NODAT at year 1. NODAT patients had lower levels of pretransplant Mg as compared with non-NODAT patients (P<0.02). When patients were divided into tertiles of Mg level, NODAT developed more frequently in patients in the lower tertile (Mg <2 mg/dL) as compared with patients in the higher tertile (Mg >2.3 mg/dL) (log rank, P<0.05). A multivariate analysis after adjustment to several variables demonstrated pretransplant Mg to be an independent risk factor of NODAT. CONCLUSION: This study supports that a low pretransplant Mg level is an independent risk factor of NODAT in kidney transplant recipients.

Automated titration of propofol and remifentanil decreases the anesthesiologist's workload during vascular or thoracic surgery: a randomized prospective study.

Closed loop target-control infusion systems using a Bispectral (BIS) signal as an input (TCI Loop) can automatically maintain intravenous anesthesia in a BIS range of 40-60 %. Our purpose was to assess to what extent such a system could decrease anesthesia workload in comparison to the use of a stand alone TCI system manually adjusted to fit the same BIS range of 40-60 % (TCI Manual). Patients scheduled for elective vascular or thoracic surgery were randomized to the TCI Loop or TCI Manual method for administering propofol and remifentanil during both induction and maintenance of general anesthesia. Assessment of workload was performed by an independent observer who quoted each time the physician looked at the BIS monitor. The number of propofol and remifentanil target modifications, the percentage of time of adequate anesthesia i.e. BIS in the range 40-60 and hemodynamic data were recorded. Eighteen patients per group were enrolled. Characteristics, duration of surgery and propofol-remifentanil consumption were similar between groups. However, the percentage of time in the BIS range 40-60 % was higher in the TCI Loop versus TCI Manual groups (94 % ± 12 vs. 74 % ± 19, p < 0.001). Mean arterial pressure was lower with TCI Manual (78 ± 6 vs. 88 ± 13 mmHg, p < 0.001). The number of times the anesthesiologist watched the controller or BIS monitor (p < 0.05) and the number of manual adjustments (p < 0.001) performed in each group was lower with TCI Loop group during induction and maintenance of anesthesia. An automated controller strikingly frees the anesthesiologist from manual intervention to adjust drug delivery.

Long-term maintenance immunosuppressive regimen with tacrolimus monotherapy.

BACKGROUND: The long-term outcome of kidney transplant recipients on monotherapy with calcineurin inhibitors has been poorly analyzed. This study aimed to describe the long-term outcome of patients on Tac monotherapy (mTac) and to compare this regimen to a standard dual therapy with Tac/MMF. MATERIAL AND METHODS: This retrospective study included 84 consecutive first kidney recipients transplanted between 1998 and 2003 and followed until 2010. Patients were treated with mTac after the 6th month of transplantation. Survival and incidence of adverse events were analyzed and compared to those of patients treated with Tac/MMF as maintenance regimen after the 6th month of transplantation. RESULTS: Mean follow-up of the mTac cohort was 8.7 ± 2.2 years. Overall patient and graft survival of the mTac cohort was 91.3% and 86.6%, respectively, at year 8 posttransplant. Tac monotherapy was started in 93.3% of patients at month 6 posttransplant and maintained in 50% of the cohort at the end of the follow-up period. Incidence of acute rejection (AR) and chronic allograft nephropathy (CAN) were 11.9% and 16.6%, respectively. Kaplan-Meyer analysis did not show any difference in patient and graft survival between mTac patients and patients under Tac/MMF. At year 6, compared to Tac/MMF patients, mTac patients had a significantly lower incidence of AR after the 6th month posttransplant and no difference in CAN, cancer, NODAT, and cardiovascular events incidence. CONCLUSIONS: This work suggests that long-term maintenance immunosuppression with mTac is safe in low-immunological risk patients and should be considered for use especially in patients with MMF intolerance.

The walking-induced transient hack concept is valid & relies on a transient early-exercise hypoxemia.

BACKGROUND: Decreased arterial oxygen pressure obtained at peak exercise is strong evidence of walking-induced hypoxemia, assuming that the lower pressure occurs just before exercise is stopped. Using empirical predefined models and transcutaneous oximetry, we have shown that some patients reporting exercise intolerance show a minimal value at the onset of walking and a post-exercise overshoot. These changes are referred to as transcutaneous "walking-induced transient hacks". METHODS: In 245 patients, walking-induced transcutaneous oxygen pressure changes in the chest were analyzed using observer-independent clustering techniques. Clustering classes were compared to the profile types previously proposed with the cross-correlation technique. The classifications of patients according to both approaches were compared using kappa statistics. In 10 patients showing a hack on transcutaneous oximetry, we analyzed the results of direct iterative arterial sampling recorded during a new walking treadmill test. RESULTS: Clustering analysis resulted in 4 classes that closely fit the 4 most frequently proposed empirical models (cross-correlation coefficients: 0.93 to 0.97). The kappa between the two classifications was 0.865. In 10 patients showing transcutaneous hacks, the minimal direct arterial oxygen pressure value occurred at exercise onset, and these patients exhibited a recovery overshoot reaching a maximum at two minutes of recovery, confirming the walking-induced transient hypoxemia. CONCLUSIONS: In patients reporting exercise intolerance, transcutaneous oximetry could help to detect walking-induced transient hypoxemia, while peak-exercise arterial oximetry might be normal.

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.

Surgical reconstruction of the superior vena cava system: indications and results.

BACKGROUND: Obstruction of the superior vena cava (SVC) secondary to malignant or benign diseases is rarely treated by surgical reconstruction. The purpose of this retrospective study is to report our experience and compare our results with previous data in the literature. METHODS: From 1993 to 2006, 24 patients underwent operative reconstruction of the SVC. Mean patient age was 58 years. The underlying disease was primary bronchopulmonary malignant neoplasm in 50%, mediastinal malignant neoplasm in 21%, and symptomatic benign disease in 29%. Forty-six percent of patients presented clinical signs of superior vena cava compression (SVCC). Our indications were based on two criterions: clinical symptoms of superior vena caval compression or histological examination of the superior vena caval lesion that indicates potential for complete surgical excision. RESULTS: Median duration of postoperative intensive care was two days. Mortality at 30 days was 12% for malignant diseases. All patients presenting clinical signs of SVCC improved. Mean follow-up was 28 months (range, 1-129). No thrombosis was observed during follow-up. Overall survival was 53% at 1 year and 35% at 5 years. For patients with malignant bronchopulmonary disease, survival was 50% at 1 year and 25% at 5 years. Mortality was 0% for patients with benign disease. CONCLUSION: Review of the literature indicates that replacement of the SVC is an uncommon procedure. Our experience suggests that the need for SVC reconstruction should not, however, be considered as a contraindication for resection of a bronchopulmonary or mediastinal neoplasm in an otherwise potentially curable patient, provided it can be achieved in a single block with clear margins. Replacement of the SVC can also be performed with low mortality and morbidity for effective treatment of SVCC secondary to benign disease that fails to respond to medical therapy.