Incidence of postoperative delirium in elderly ambulatory patients: A prospective evaluation using the FAM-CAM instrument.

BACKGROUND: While the incidence of postoperative delirium is high in aged hospitalized patients undergoing major surgery, little is known concerning patients undergoing ambulatory surgery. OBJECTIVE: To determine the incidence of postoperative delirium in aged patients after hospital discharge from an ambulatory surgery unit. DESIGN: Prospective observational study. PATIENTS: Elderly patients (≥75 years) scheduled for a surgical procedure on an ambulatory basis. INTERVENTIONS: Filling of the Family Confusion Assessment Method (FAM-CAM) questionnaire (11 items) during a phone interview of family caregivers on two separate occasions: five to three days before surgery, and three to five days after surgery. MAIN OUTCOME MEASURES: The detection of acute onset and fluctuating course inattention, disorganized thinking, altered level of consciousness, disorientation, perceptual disturbances, and psychomotor agitation from the observations of family caregivers. RESULTS: Signs of delirium appeared de novo in 2 of 141 patients (incidence 1.4%) in the postoperative period: a 80-years old man who was disoriented and had incoherent and illogical speech on postoperative day 1 of resection of a cephalic cutaneous melanoma under local anesthesia and sedation (midazolam, sufentanil, and propofol), and a 83-years old woman with a pre-existing mental confusion, who experienced visual and hearing hallucinations and had inappropriate behaviour on postoperative day 2 of cataract surgery performed under episcleral block. Both patients returned to their preoperative states within a few days. CONCLUSIONS: Using the FAM-CAM instrument for the detection of postoperative delirium in ambulatory patients, the study showed that the incidence of cognitive changes in the ambulatory setting is very low. Among several putative factors, the lightness of the surgical procedure, the wide use of regional anesthesia, and the short hospital stay may be contributing factors to this result. The findings of this study need to be confirmed in a larger sample of patients.

Spinal anesthesia-induced hypotension: a risk comparison between patients with severe preeclampsia and healthy women undergoing preterm cesarean delivery.

We previously showed that, in comparison with term healthy parturients, patients with severe preeclampsia had a less frequent incidence of spinal hypotension, which was less severe and required less ephedrine. In the present study, we hypothesized that these findings were attributable to preeclampsia-associated factors rather than to a smaller uterine mass. The incidence and severity of hypotension were compared between severe preeclamptics (n = 65) and parturients with preterm pregnancies (n = 71), undergoing spinal anesthesia for cesarean delivery (0.5% bupivacaine, sufentanil, morphine). Hypotension was defined as the need for ephedrine (systolic blood pressure <100 mm Hg in parturients with preterm fetuses or 30% decrease in mean blood pressure in both groups). Apgar scores and umbilical arterial blood pH were also studied. Neonatal and placental weights were similar between the groups. Hypotension was less frequent in preeclamptic patients than in women with preterm pregnancies (24.6% versus 40.8%, respectively, P = 0.044). Although the magnitude of the decrease in systolic, diastolic, and mean arterial blood pressure was similar between groups, preeclamptic patients required less ephedrine than women in the preterm group to restore blood pressure to baseline levels (9.8 +/- 4.6 mg versus 15.8 +/- 6.2 mg, respectively, P = 0.031). The risk of hypotension in the preeclamptic group was almost 2 times less than that in the preterm group (relative risk = 0.603; 95% confidence interval, 0.362-1.003; P = 0.044). The impact of Apgar scores was minor, and umbilical arterial blood pH was not affected. We conclude that preeclampsia-associated factors, rather than a smaller uterine mass, account for the infrequent incidence of spinal hypotension in preeclamptic patients.

Patients with severe preeclampsia experience less hypotension during spinal anesthesia for elective cesarean delivery than healthy parturients: a prospective cohort comparison.

In this prospective cohort study, we compared the incidence and severity of spinal anesthesia (SA)-associated hypotension in severely preeclamptic (n = 30) versus healthy (n = 30) parturients undergoing cesarean delivery. After the administration of IV fluids, SA was performed with hyperbaric 0.5% bupivacaine, sufentanil, and morphine. Blood pressure (BP) was recorded before and at 2-min intervals for 30 min after SA. Clinically significant hypotension was defined as the need for ephedrine (systolic BP decrease to <100 mm Hg in healthy parturients or 30% decrease in mean BP in both groups). Despite receiving a smaller fluid volume (1653 +/- 331 mL versus 1895 +/- 150 mL; P = 0.005) and a larger bupivacaine dose (10.5 +/- 0.9 mg versus 10.0 +/- 0.7 mg; P = 0.019), the severely preeclamptic patients had a less frequent incidence of clinically significant hypotension (16.6% versus 53.3%; P = 0.006), which was less severe and required less ephedrine. The risk of hypotension was almost six times less in severely preeclamptic patients (odds ratio, 0.17; 95% confidence interval, 0.05-0.58; P = 0.006) than that in healthy patients.

Comparison of the effects of racemic bupivacaine, levobupivacaine, and ropivacaine on ventricular conduction, refractoriness, and wavelength: an epicardial mapping study.

BACKGROUND: The study was designed to compare the effects of equimolar concentrations of racemic bupivacaine, levobupivacaine, and ropivacaine on ventricular conduction, anisotropy, duration and homogeneity of refractoriness, and wavelengths, and to provide a potency ratio for effects on conduction velocity. METHODS: Isolated frozen rabbit hearts (which leave a thin layer of surviving epicardial muscle) were treated with 0.1, 1, and 10 mum racemic bupivacaine, levobupivacaine, or ropivacaine. Left ventricular longitudinal and transverse conduction velocities, anisotropic ratio, minimum pacing cycle length, use dependency, duration and dispersion of ventricular effective refractory period, and wavelengths were studied. A high-resolution mapping system was used for data acquisition. In addition to two-way analysis of variance for repeated measures, data for conduction velocities were fitted simultaneously using a nonlinear mixed-effect modeling program to allow intergroup comparison. RESULTS: Each agent induced a concentration- and use-dependent slowing of conduction velocities, with no change of the anisotropic ratio. The use-dependent effect of levobupivacaine is similar to that of racemic bupivacaine concerning longitudinal conduction velocity. Fitting of conduction velocities provided a racemic bupivacaine to levobupivacaine and to ropivacaine ratio of 1:1.38 for concentration effect at 1,000-ms pacing cycle length, and 1:0.74 for use-dependent effect at 600-ms pacing cycle length. Racemic bupivacaine and levobupivacaine prolonged the ventricular effective refractory period, whereas ropivacaine did not. No dispersion in ventricular effective refractory period values occurred. All three agents induced significant decreases in wavelengths. This effect was not different among groups. CONCLUSIONS: Differences among racemic bupivacaine, levobupivacaine, and ropivacaine at equimolar concentrations are mainly caused by the use-dependent effects on conduction velocities and the concentration-dependent effects on ventricular effective refractory period. Therefore, one must take into account the corresponding pacing rates when comparing the potency ratios of local anesthetics.