Jean-Emmanuel de La Coussaye

An Increase in Aortic Blood Flow after an Infusion of 100 ml Colloid over 1 Minute Can Predict Fluid Responsiveness The Mini-fluid Challenge Study

Background: Predicting fluid responsiveness remains a difficult question in hemodynamically unstable patients. The authors objective was to test whether noninvasive assessment by transthoracic echocardiography of subaortic velocity time index (VTI) variation after a low volume of fluid infusion (100 ml hydroxyethyl starch) can predict fluid responsiveness. Methods: Thirty-nine critically ill ventilated and sedated patients with acute circulatory failure were prospectively studied. Subaortic VTI was measured by transthoracic echocardiography before fluid infusion (baseline), after 100 ml hydroxyethyl starch infusion over 1 min, and after an additional infusion of 400 ml hydroxyethyl starch over 14 min. The authors measured the variation of VTI after 100 ml fluid (&Dgr;VTI100) for each patient. Receiver operating characteristic curves were generated for (&Dgr;VTI100). When available, receiver operating characteristic curves also were generated for pulse pressure variation and central venous pressure. Results: After 500 ml volume expansion, VTI increased ≥ 15% in 21 patients (54%) defined as responders. &Dgr;VTI100 ≥ 10% predicted fluid responsiveness with a sensitivity and specificity of 95% and 78%, respectively. The area under the receiver operating characteristic curves of &Dgr;VTI100 was 0.92 (95% CI: 0.78–0.98). In 29 patients, pulse pressure variation and central venous pressure also were available. In this subgroup of patients, the area under the receiver operating characteristic curves for &Dgr;VTI100, pulse pressure variation, and central venous pressure were 0.90 (95% CI: 0.74–0.98, P < 0.05), 0.55 (95% CI: 0.35–0.73, NS), and 0.61 (95% CI: 0.41–0.79, NS), respectively. Conclusion: In patients with low volume mechanical ventilation and acute circulatory failure, &Dgr;VTI100 accurately predicts fluid responsiveness.

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.

pulsed Doppler Ultrasonography Guidance for Catheterization of the Subclavian Vein : a Randomized Study

Background Catheterization of the subclavian vein may lead to severe complications. The current randomized study compared a technique of pulsed Doppler ultrasonography guidance and the standard method for subclavian vein catheterization. Methods Standard and Doppler ultrasonography guidance methods were performed by the same physician in 286 patients, 143 in each group. Primary end points were immediate complications (arterial puncture, pneumothorax, wrong position of catheter tip), failures, the number of subclavian vein catheterizations with immediate complication or failure, the number of skin punctures per catheterization, and the time to placement of the guide wire. The secondary end points were the determination of predicting factors of successful cannulation in each group. Results Both groups were similar according to morphologic parameters of the patients. A greater number of subclavian vein catheterizations were performed on the right side using Doppler guidance (105 vs. 73, P < 0.01). Doppler guidance decreased complications (5.6% vs. 16.8%, P < 0.01), largely because of a smaller number of catheters for which the tip was defined to be in incorrect position (0.7% vs. 7.7%, P < 0.01). The time to catheterization was longer with Doppler guidance (300 vs. 27 s, P < 0.001). Failures, catheterizations of the subclavian vein with immediate complications or failure, and the total number of skin punctures per catheterization were similar in both groups. Using Doppler guidance, the presence of a good Doppler signal (124 of 143) was predictive of successful catheterization (123 successful cannulations, P < 0.001). Conclusions Doppler guidance reduces the incidence of inappropriately positioned subclavian catheters.

Peribulbar versus retrobulbar anesthesia for ophthalmic surgery: an anatomical comparison of extraconal and intraconal injections.

BackgroundPeribulbar and retrobulbar anesthesia have long been opposed on the basis of the existence of an intermuscular membrane, which is supposed to separate the intraconal from the extraconal spaces in a water-tight fashion. A local anesthetic injected outside the cone should spread through this septum to reach the nerves to be blocked. The existence of this septum is questioned. The aim of this study was to compare the spread of a colored latex dye injected intraconally or extraconally to simulate both retrobulbar and peribulbar anesthesia. MethodsThe authors used 10 heads from human cadavers. For each head, one eye was injected intraconally, and the other eye was injected extraconally. The heads were then frozen and sectioned into thin slices following various planes. They were then photographed and observed. ResultsThere was no evidence of the existence of an intermuscular septum separating the intraconal and extraconal spaces. Those two spaces appeared to be part of a common spreading space, the corpus adiposum of the orbit. ConclusionsThese results are in accord with the fact that clinical studies were not able to clearly demonstrate that retrobulbar anesthesia is more efficient than peribulbar anesthesia. On the basis of a similar clinical efficacy of the two techniques as a result of similar spreading of the local anesthetic injected, and a potentially higher risk of introducing the needle into the muscular cone, the authors recommend replacing retrobulbar anesthesia with peribulbar anesthesia.

Predicting peripheral venous access difficulty in the emergency department using body mass index and a clinical evaluation of venous accessibility.

BACKGROUND Peripheral venous (PV) cannulation, one of the most common technical procedures in Emergency Medicine, may prove challenging, even to experienced Emergency Department (ED) staff. Morbid obesity (body mass index [BMI] ≥ 40) has been reported as a risk factor for PV access failure in the operating room. OBJECTIVES We investigated PV access difficulty in the ED, across BMI categories, focusing on patient-related predicting factors. METHODS Prospective, observational study including adult patients requiring PV lines. Operators were skilled nurses and physicians. PV accessibility was clinically evaluated before all cannulation attempts, using vein visibility and palpability. Patient and PV placement characteristics were recorded. Primary outcome was failure at first attempt. Outcome frequency and comparisons between groups were examined. Predictors of difficult cannulation were explored using logistic regression. A p-value <0.05 was considered significant. RESULTS PV lines were placed in 563 consecutive patients (53 ± 23 years, BMI: 26 ± 7 kg/m(2)), with a success rate of 98.6%, and a mean attempt of 1.3 ± 0.7 (range 1-7). Failure at the first attempt was recorded in 21% of patients (95% confidence interval [CI] 17.6-24.4). Independent risk factors were: a BMI ≥ 30 (odds ratio [OR] 1.98, 95% CI 1.09-3.60), a BMI < 18.5 (OR 2.24; 95% CI 1.07-4.66), an unfavorable (OR 1.66, 95% CI 1.02-2.69), and very unfavorable clinical assessment of PV accessibility (OR 2.38, 95% CI 1.15-4.93). CONCLUSION Obesity, underweight, an unfavorable, and a very unfavorable clinical evaluation of PV accessibility are independent risk factors for difficult PV access. Early recognition of patients at risk could help in planning alternative approaches for achieving rapid PV access.

The intrathoracic blood volume index as an indicator of fluid responsiveness in critically ill patients with acute circulatory failure: a comparison with central venous pressure.

BACKGROUND: The intrathoracic blood volume index (ITBVI) and central venous pressure (CVP) are routinely used to predict fluid responsiveness in critically ill patients with acute circulatory failure (systolic blood pressure <90 mm Hg or vasopressor requirement). However, they have never been compared. METHODS: In this prospective interventional study, we included 35 (21 men) mechanically ventilated and sedated patients with acute cardiovascular failure requiring cardiac output measurement (transpulmonary thermodilution technique). Fluid responsiveness was defined as an increase in stroke index (cardiac output/heart rate/body surface area) ≥15%. Receiver operating characteristic curves were generated for ITBVI and CVP. RESULTS: Fluid challenge induced a stroke index increase ≥15% in 18 (51%) patients (responders). At baseline, no studied hemodynamic variables were different between responders and nonresponders. The areas under the receiver operating characteristic curves were 0.64 [95% CI: 0.46–0.80] for ITBVI and 0.68 [95% CI: 0.50–0.83] for CVP, without any statistical difference (P = 0.73). The best cut-off values for CVP and ITBVI were 9 mm Hg (sensitivity = 61%; specificity = 82%) and 928 mL · m−2 (sensitivity = 78%; specificity = 53%). CONCLUSION: ITBVI is similar to CVP in its ability to predict fluid responsiveness in critically ill patients with acute circulatory failure.

Cardiac output measurement in critically ill patients: comparison of continuous and conventional thermodilution techniques

The purpose of the study was to compare cardiac output (CO) measurement by continuous (CTD) with that by conventional thermodilution (TD) in critically ill patients. In 19 of 20 critically ill patients requiring a pulmonary artery catheterism, 105 paired CO measurements were performed by both CTD and TD. Regression analysis showed that: CTD CO = 1.18 TD CO − 0.47. Correlation coefficient was 0.96. Bias and limit of agreement were — 0.8 and 2.4 L · min−1, respectively. When a Bland and Altman diagram was constructed according to cardiac index ranges, biases were −0.2 and −0.3 and −0.8 L · min−1 · m−2 and limits of agreement were 0.3, 0.7 and 1.6 L · min−1 · m−2 for low (<2.5 L · min−1 · m−2), normal (between 2.5 and 4.5 L · min−1 · m−2) and high (> 4.5 L · min−1 · m−2) cardiac indexes, respectively. It is concluded that CTD, compared with TD, is a reliable method of measuring CO, especially when cardiac index is ≤4.5 L · min−1 · m−2.RésuméCette étude avait pour but de comparer les mesures du débit cardiaque réalisées par thermodilution continue (CTD) par rapport à la thermodilution classique (TD) chez des patients de réanimation. Cent cinq paires de mesures du débit cardiaque ont été comparées chez 19 des 20 patients de réanimation inclus dans l’étude. L’équation de la droite de régression est CTD CO = 1,18 TD CO − 0,47. Le coefficient de corrélation s’élève à 0,96. L’erreur moyenne et l’intervalle de confiance sont respectivement de −0,8 et 2,4 L · min−1. En réalisant un diagramme de Bland and Altman selon le niveau d’index cardiaque, les erreurs moyennes s’élèvent à −0,2, −0,3 et −0,8 L · min−1 · m−2 et les intervalles de confiance à 0,3, 0,7 et 1,6 L · min−1 · m−2, respectivement pour les index cardiaques bas (<2,5 L · min−1 · m−2), normaux (entre 2,5 et 4,5 L · min−1 · m−2) et hauts (> 4,5 L · min−1 · m−2). La thermodilution continue, comparée à la thermodilution classique, est une méthode fiable pour le monitorage du débit cardiaque surtout pour les index cardiaque ≤4,5 L · min−1 · m−2.

Ultrasound guidance for radial arterial puncture: a randomized controlled trial

UNLABELLED STUDY OBJECTIVE AND BACKGROUND: Arterial puncture for blood gas analysis is a frequent procedure and could be difficult in the emergency setting. The aim of the study was to compare ultrasonographically guided arterial radial puncture vs conventional sampling. MATERIALS AND METHODS This is a prospective, randomized study. The inclusion criteria are all patients needing arterial blood gas at admission in the emergency unit. The exclusion criteria are the following: Hallen test positive, local sepsis, local trauma, known sever local arteriopathy, refusal of consent by the patient, participation in another study, and cardiac arrest. Patients were randomized into 2 groups: radial arterial puncture obtained through an ultrasonographically guided technique (group 1) or radial arterial puncture by conventional method (group 2). The main objective is the number of attempts after enrollment. The secondary objectives are time to success, patient satisfaction and pain, and physician satisfaction. Immediate complications were collected. Groups were compared with nonparametric analysis. RESULTS The data were usable for 72 of 74 patients included. Lung disease (acute exacerbation of chronic obstructive pulmonary disease and pneumonia) at 45% (n = 32) and suspicion of pulmonary embolism in 31% (n = 22) were the most common reasons. Demographics data were comparable in the 2 groups. In group 1, the number of attempts significantly increased (2.35 [1-3] vs 1.66 [1-2] [P = .017]), and the sample was 2.4 times longer (132 seconds [50-200] vs 55 [20-65] [P < .01] by standard method). There was no significant difference in terms of pain (visual analog scale [VAS], 3.6 [2-5] for both groups [P = .743]), patient satisfaction (VAS, 7.2 [5-9] vs 6.8 [5-9] [P = .494]), and physician satisfaction (VAS, 6.0 [3.5-8] vs 6.9 [5-9] [P = .233]). No immediate complications were found in the 2 groups. CONCLUSION Ultrasonographically guided arterial puncture increases the number and duration of implementations. This technique, however, does not alter the patients pain, the number of immediate complications, or patient and physician satisfaction.

Caruncle single injection episcleral (Sub-tenon) anesthesia for cataract surgery: mepivacaine versus a lidocaine-bupivacaine mixture.

UNLABELLED We compared the quality of anesthesia provided by mepivacaine 2% or a mixture of lidocaine 2%-bupivacaine 0.5%, both with hyaluronidase, in caruncle single-injection episcleral (sub-Tenon) anesthesia. Sixty patients undergoing cataract surgery were included in this randomized, double-blinded study. The time to the onset of blockade, maximal akinesia, need for supplemental injection, and time to recovery were recorded. With mepivacaine, the time to onset was slightly shorter, and the akinesia score higher, than with the mixture. Although statistically significant, these differences are small. With mepivacaine, the time to recovery was shorter. We conclude that the reproducible short duration of the block may be an advantage in outpatient surgery. IMPLICATIONS We compared the classic mixture of lidocaine 2% plus bupivacaine 0.5% to mepivacaine 2% for caruncle episcleral (sub-Tenon) anesthesia for cataract surgery. Mepivacaine provided a more efficient block with a quicker onset and a quicker recovery. However, these differences were very small and were of little clinical interest.

Time-course of cardiac troponin I release from isolated perfused rat hearts during hypoxia/reoxygenation and ischemia/reperfusion

The study was designed to determine the time-course of cardiac troponin I (cTn-I) release in isolated and Langendorff-perfused rat hearts during hypoxia and reoxygenation (H/Reox), and after various durations of total ischemia and subsequent reperfusion (I/R). For this purpose, in H/Reox, cTn-I was measured with the conventional Access immunoassay (ng/ml) and a new immunoassay which operates at pg/ml, and compared with creatine kinase (CK), lactate dehydrogenase (LD) and cardiac troponin T (cTn-T). In I/R, cTn-I was compared with CK and LD. The anti-Tn-I mAbs used in cTn-I assays cross-react with cTn-I of the rat. A clear difference between time-courses and concentration levels of cTn-I in I/R and H/Reox models was found. In I/R, maximum release of cTn-I, CK and LD similarly occurred within minutes following reperfusion; however cTn-I did not return to baseline values. cTn-I levels were not linked to the duration of ischemia. In I/R, we were only able to detect small cTn-I concentrations. In H/Reox experiments, cTn-I, CK and LD increased time-dependently. We found higher cTn-I maximal peak levels detected with the Access immunoassay than with the new assay (median, 0.346 ng/ml per min/g dry wt vs 132 pg/ml per min/g dry wt). cTn-T maximal concentrations were lower than maximal cTn-I levels (median, 0.117 ng/ml per min/g dry wt). Time-courses of cTn-I release were roughly similar with both assays in the H/Reox model (r = 0.90). These data indicate that the cTn-I time-course is related to experimental model (I/R or H/Reox), but also likely depends on the sensitivity of cTn-I assays in such experimental conditions.