Dynamic arterial elastance measured by uncalibrated pulse contour analysis predicts arterial-pressure response to a decrease in norepinephrine.

BACKGROUND: Dynamic arterial elastance (Eadyn) has been proposed as an indicator of vascular tone that predicts the decrease in arterial pressure in response to changes in norepinephrine (NE). The purpose of this study was to determine whether Eadyn measured by uncalibrated pulse contour analysis (UPCA) can predict a decrease in arterial pressure when the NE dosage is decreased. METHODS: We conducted a prospective study in a university hospital intensive care unit. Patients with vasoplegic syndrome for whom the intensive care physician planned to decrease the NE dosage were included. Haemodynamic and UPCA (VolumeView and FloTrac; Edwards Lifesciences, Irvine, CA, USA) values were obtained before and after decreasing the NE dosage. Responders were defined by a >10% decrease in mean arterial pressure (MAP). RESULTS: Of 35 patients included, 11 (31%) were pressure responders with a median decrease of 13%. Eadyn was correlated to systolic arterial pressure (SAP) (r=0.255; P=0.033), diastolic arterial pressure (r=0.271; P=0.024), MAP (r=0.310; P=0.009), heart rate (r=0.543; P=0.0001), and transthoracic echography cardiac output (r=0.264; P=0.024). Baseline Eadyn was correlated with MAP changes (r=0.394; P=0.019) and SAP changes (r=0.431; P=0.009). Eadyn predicted the decrease in arterial pressure with an area under the receiver-operating-characteristic curve of 0.84 (95% confidence interval: 0.70-0.97). The best cut-off was 0.90. CONCLUSIONS: The present study confirms the ability of Eadyn measured by UPCA to predict an arterial pressure response to a decrease in NE. Eadyn may constitute an easy-to-use functional approach to arterial tone assessment regardless of the monitor used to measure its determinant. CLINICAL TRIAL REGISTRATION: DRCIT95.

Compliance with an empirical antimicrobial protocol improves the outcome of complicated intra-abdominal infections: a prospective observational study.

BACKGROUND: Despite improvements in medical and surgical care, mortality attributed to complicated intra-abdominal infections (cIAI) remains high. Appropriate initial antimicrobial therapy (ABT) is key to successful management. The main causes of non-compliance with empirical protocols have not been clearly described. METHODS: An empirical ABT protocol was designed according to guidelines, validated in the institution and widely disseminated. All patients with cIAI (2009-2011) were then prospectively studied to evaluate compliance with this protocol and its impact on outcome. Patients were classified into two groups according to whether or not they received ABT in compliance with the protocol. RESULTS: 310 patients were included: 223 (71.9%) with community-acquired and 87 (28.1%) with healthcare-associated cIAI [mean age 60(17-97) yr, mean SAPS II score 24(16)]. Empirical ABT complied with the protocol in 52.3% of patients. The appropriateness of empirical ABT to target the bacteria isolated was 80%. Independent factors associated with non-compliance with the protocol were the anaesthetist's age ≥36 yr [OR 2.1; 95%CI (1.3-3.4)] and the presence of risk factors for multidrug-resistant bacteria (MDRB) [OR 5.4; 95%CI (3.0-9.5)]. Non-compliance with the protocol was associated with higher mortality (14.9 vs 5.6%, P=0.011) and morbidity: relaparotomy (P=0.047), haemodynamic failure (P=0.001), postoperative pneumonia (P=0.025), longer duration of mechanical ventilation (P<0.001), longer ICU stay (P<0.001) and longer hospital stay (P=0.002). On multivariate logistic regression analysis, non-compliance with the ABT protocol was independently associated with mortality [OR 2.4; 95% CI (1.1-5.7), P=0.04]. CONCLUSIONS: Non-compliance with empirical ABT guidelines in cIAI is associated with increased morbidity and mortality. Information campaigns should target older anaesthetists and risk factors for MDRB.

[French national survey on difficult intubation in intensive care units]. / Enquête nationale sur l'intubation difficile dans les services de réanimation français.

OBJECTIVES: Assessing the theoretical knowledge, practical experience of French intensivists, and their compliance with French Anesthesiology and Critical Care Society's difficult airway algorithms of the expert's SFAR conference of 2006. STUDY DESIGN: Prospective and descriptive national survey. MATERIAL AND METHODS: An anonymous questionnaire with 40 questions was emailed to physicians working in intensive care units in France. RESULTS: Five hundred and eight intensivists answered the survey. Ninety-seven percent of physicians reported having a portable storage unit for difficult intubation. As for practical experience, 421 physicians (83 %) have set up less than 10 laryngeal mask airway, 257 (51 %) have performed less than 10 intubations under fibroscopy and 269 (53 %) have never performed a cricothyroidotomy on mannequin, and 331 (65 %) on a patient. In case of emergency intubation, 29 % of them do not use a rapid sequence induction. Three hundred physicians (59 %) use capnography as monitoring of the endotracheal position. Two hundred and nine (42 %) consider they have not been trained to difficult intubation and 443 (87 %) would like to participate in high fidelity simulations mannequin. CONCLUSIONS: National airway management algorithm was insufficiently followed. Alternative techniques do not seem to be mastered by all physicians. French intensivists expect more training on difficult intubation, including high fidelity simulation.

Accuracy of impedance cardiography for evaluating trends in cardiac output: a comparison with oesophageal Doppler.

BACKGROUND: Impedance cardiography (ICG) enables continuous, beat-by-beat, non-invasive, operator-independent, and inexpensive cardiac output (CO) monitoring. We compared CO values and variations obtained by ICG (Niccomo™, Medis) and oesophageal Doppler monitoring (ODM) (CardioQ™, Deltex Medical) in surgical patients. METHODS: This prospective, observational, single-centre study included 32 subjects undergoing surgery with general anaesthesia. CO was measured simultaneously with ICG and ODM before and after events likely to modify CO (vasopressor administration and volume expansion). One hundred and twenty pairs of CO measurements and 94 pairs of CO variation measurements were recorded. RESULTS: The CO variations measured by ICG correlated with those measured by ODM [r=0.88 (0.82-0.94), P<0.001]. Trending ability was good for a four-quadrant plot analysis with exclusion of the central zone (<10%) [95% confidence interval (CI) for concordance (0.86; 1.00)]. Moderate to good trending ability was observed with a polar plot analysis (angular bias: -7.2°; 95% CI -12.3°; -2.5°; with radial limits of agreement -38°; 24°). After excluding subjects with chronic obstructive pulmonary disease, a Bland-Altman plot showed a mean bias of 0.47 litre min(-1), limits of agreements between -1.24 and 2.11 litre min(-1), and a percentage error of 35%. CONCLUSION: ICG appears to be a reliable method for the non-invasive monitoring of CO in patients undergoing general surgery.

Evaluation of pulse pressure variation validity criteria in critically ill patients: a prospective observational multicentre point-prevalence study.

BACKGROUND: Respiratory variation in pulse pressure (ΔPP) is commonly used to predict the fluid responsiveness of critically ill patients. However, some researchers have demonstrated that this measurement has several limitations. The present study was designed to evaluate the proportion of patients satisfying criteria for valid application of ΔPP at a given time-point. METHODS: A 1 day, prospective, observational, point-prevalence study was performed in 26 French intensive care units (ICUs). All patients hospitalized in the ICUs on the day of the study were included. The ΔPP validity criteria were recorded prospectively and defined as follows: (i) mechanical ventilation in the absence of spontaneous respiration; (ii) regular cardiac rhythm; (iii) tidal volume ≥8 ml kg(-1) of ideal body weight; (iv) a heart rate/respiratory rate ratio >3.6; (v) total respiratory system compliance ≥30 ml cm H2O(-1); and (vi) tricuspid annular peak systolic velocity ≥0.15 m s(-1). RESULTS: The study included 311 patients with a Simplified Acute Physiology Score II of 41 (39-43). Overall, only six (2%) patients satisfied all validity criteria. Of the 170 patients with an arterial line in place, only five (3%) satisfied the validity criteria. During the 24 h preceding the study time-point, fluid responsiveness was assessed for 79 patients. ΔPP had been used to assess fluid responsiveness in 15 of these cases (19%). CONCLUSIONS: A very low percentage of patients satisfied all criteria for valid use of ΔPP in the evaluation of fluid responsiveness. Physicians must consider limitations to the validity of ΔPP before using this variable.

[Storage at room temperature does not change cisatracurium onset time: a prospective, randomized, double-blind controlled study]. / La température de conservation du cisatracurium ne modifie pas le délai d'action: étude randomisée, en double insu

OBJECTIVE: Storage of cisatracurium at room temperature seems to have no effect on its degradation in vitro contrary to the recommendations of storage at +4°C. The purpose of this study was to evaluate the influence of cisatracurium' s storage temperature on its onset time. STUDY DESIGN: Prospective, randomized, double-blind trial study. PATIENTS AND METHODS: Thirty patients were enrolled. The control group consisted of 15 patients receiving cisatracurium (0.15mg/kg) stored at room temperature and the intervention consisted of 15 patients receiving cisatracurium (0.15mg/kg) stored at +4°C. The primary endpoint was to compare cisatracurium onset time depending on the storage temperature. RESULTS: Cisatracurium onset time was 235 (180-292) seconds in the "room temperature" group vs. 240 (210-292) seconds in the "refrigerated" group. There was no difference between the onset of cisatracurium depending on the temperature of storage (p=0.51). Subgroups analysis in the "room temperature" group did not show any difference in cisatracurium onset depending on whether it was stored at room temperature for one, two or three weeks. Excellent intubation score was obtained for 100% of the patients. CONCLUSION: This study demonstrated that cisatracurium's storage at room temperature had no influence on its onset time. It provides an argument for the preservation of cisatracurium at room temperature for a period not exceeding 21 days. Monitoring the onset of curarization may increase the quality score of intubation.

Assessment of an uncalibrated pressure waveform device's ability to track cardiac output changes due to norepinephrine dose adjustments in patients with septic shock: a comparison with Doppler echocardiography.

OBJECTIVES: The FloTrac Vigileo (FTV) estimates cardiac output (CO) on the basis of an uncalibrated arterial pressure waveform. To assess the ability of the third-generation of FTV (v.3.02) to track changes in CO following norepinephrine dose adjustment in patients with septic shock, we performed a comparative study using Doppler echocardiography (DE). STUDY DESIGN: Prospective observational study. PATIENTS: We prospectively included 20 mechanically ventilated patients receiving norepinephrine and monitored with the FTV. Five minutes after each change in norepinephrine dose (decided by the attending physician), CO was measured simultaneously with the FTV (CO(FTV)) and DE (CO(DE)). The changes in CO were compared. ROC curves were built to assess the ability of FTV to detect significant changes in CO(DE) of at least 15%. RESULTS: Ninety pairs of CO variations measurements were made. The intertechnique correlation coefficient for changes in CO of at least 15% was r=0.59; P=0.0009. The AUC of a ROC curve built to test the FTV's ability to detect a CO(DE) increase of 15% or more was 0.783 (±0.083) (P=0.005). A CO(FTV) threshold value of 15% had a sensitivity of 54% (25-81) and a specificity of 87% (77-94). For a CO(DE) decrease of 15% or more, the ROC curve had an AUC of 0.616 (±0.075) (P=0.12) and a CO(FTV) threshold value of 13% yielded a sensitivity of 53% (27-79) and a specificity of 72% (60-82). CONCLUSIONS: The FTV was unable to accurately track changes in CO following norepinephrine dose adjustments in critically ill patients with septic shock.

Effect of intra-abdominal hypertension on left ventricular relaxation: a preliminary animal study.

BACKGROUND: In the intensive care unit, intra-abdominal hypertension (IAH) is a frequently encountered, life-threatening condition. The aim of this animal study was to evaluate the effect of IAH on left ventricular (LV) relaxation (i.e. the active phase of diastole). METHODS: Seven male rabbits were anaesthetized before mechanical ventilation. A 20 mm Hg increase in intra-abdominal pressure (IAP) was then induced by intraperitoneal infusion of 1.5% glycine solution. Haemodynamic parameters were recorded and the relaxation time constant tau (considered to be the best index of left ventricle relaxation) was calculated. All haemodynamic measurements were recorded at baseline and then after induction of IAH. RESULTS: A 20 mm Hg increase in IAP was not followed by a significant change in arterial pressure, but was associated with increases in central venous pressure (from 2 [-2 to 6] to 7 [-2 to 12] mm Hg, P= 0.03), LV end-diastolic pressure (from 7 [6-8] to 15 [11-19] mm Hg, P= 0.04) and the relaxation time constant tau (from 16 [14-18] to 43 [34-52] ms, P= 0.048). CONCLUSIONS: In this animal study, a 20 mm Hg increase in IAP impaired LV relaxation. Further studies are necessary to identify the causes of this impairment.

Management of supra-mesocolic peritonitis using the Levy helicoid drain (Hélisonde®).

INTRODUCTION: Postoperative peritonitis arising in the upper abdomen requiring reoperative surgery has a mortality rate of up to 50%. One therapeutic modality for these patients is the use of the Hélisonde(®) drain, designed by Levy, the Levy Helical Drain (LHD), but it has not seen widespread use. In this paper, we describe our experience in managing supramesocolic peritonitis with this drain at the University Surgical Center at Amiens and we analyze our results. PATIENTS AND METHODS: Between 2005 and 2010, we cared for 190 patients with supramesocolic peritonitis in our unit. Of these, 22 patients with gastric or duodenal fistula underwent transorificial intubation with the LHD. There were 12 men and 10 women with a mean age of 66 years. At surgery, the helical drain was screwed into the fistular orifice, two more flat drains were left adjacent to the fistula, and a jejunal feeding tube was placed. The mean interval between the initial surgery and the drainage procedure was 16.1 ± 14 days. RESULTS: The mean APACHE II score was 20 (10-28). The Mannheim score averaged 28 (19-34). The LHD was completely removed at a mean interval of 35.5 ± 11 days. Six patients (27%) died postoperatively. Postoperative complications included intraperitoneal abscess (n = 3), pneumonia (n=1), and evisceration (n = 2). Two patients required reoperation. The average hospital stay was 70.7 days. Four patients had a persistent chronic fistula. CONCLUSION: The LHD is a useful technical device in the treatment of supramesocolic peritonitis. Its management requires close oversight.

[Management of a retroperitoneal paraganglioma]. / Prise en charge d'un paragangliome rétropéritonéal.

Paragangliomas are rare tumors arising from extraadrenal chromaffin cells. We report a 43-year-old man who presented with abdominal pain. An abdominal computed tomography scan revealed a large retroperitoneal mass. During an endoscopic biopsy of this tumor, the patient experienced marked hemodynamic fluctuations with tachycardia and high blood pressure, and an extraadrenal pheochromocytoma was suspected. Measurements of plasma and urinary catecholamines and urinary total metanephrines ruled in the diagnosis. Echocardiography disclosed acute myocardial dysfunction that returned to normal after surgical resection of the paraganglioma. This report also underlines the importance of the anesthetic preparation and monitoring around the surgical procedure and the need of a long-term follow-up to detect malignant paraganglioma in the absence of histological criteria of benign tumor.

[Influence of open chest conditions on pulse pressure variations]. / Influence de l'ouverture du thorax par sternotomie sur les variations respiratoires de la pression pulsée.

OBJECTIVES: Pulse pressure variations are used to assess fluid responsiveness in mechanically ventilated patients. The accuracy of this index in open chest conditions remained unclear. The aim of the study was to evaluate the effect of open chest conditions on pulse pressure variations. STUDY DESIGN: Non-interventional prospective study. METHODS AND PATIENTS: Twenty-eight mechanically ventilated patients scheduled for open-heart surgery were included. Pulse pressure variations, peak aortic velocity, and stroke volume were measured before and after thoracotomy with pericardotomy. Measurements were made at each step and compared. RESULTS: Neither pulse pressure variation nor peak aortic velocity and nor stroke volume variation were modified by open chest conditions (median=5% [interquartile range=6] vs 4% [6], p=NS), (20% [11] vs 17% [12], p=NS and 11% [7] vs 10% [3], p=NS) respectively. Pulse pressure variations were correlated to stroke volume before thoracotomy (r'=-0.432; p=0.02) and after thorocatomy (r'=-0.433, p=0.02). CONCLUSION: In these studied patients, preload dependancy indices were not modified by open chest conditions. Pulse pressure variations remained correlated to stroke volume even after thoracotomy.

[Safety of "needle" regional anaesthesia for anterior segment surgery under antiplatelet agents and anticoagulants therapies]. / Changement de pratique en ALR ophtalmique (ALR à l'aiguille et maintien des anticoagulants) : sécurité vis-à-vis des incidents hémorragiques mineurs.

INTRODUCTION: cataracts preferentially affect the elderly. More than 560,000 procedures are performed annually in France on vulnerable patients that are exposed to cardio-circulatory conditions requiring antiplatelet and/or anticoagulants. Haemorrhagic complications resulting from cataract surgery and/or eye regional anaesthesia are rare but can lead to serious damage to eye function. PATIENTS AND METHODS: in this study, we compared the management care of two types of antiplatelet and/or anticoagulants successively utilizing the following procedure: first, the cessation of antiplatelet agents and anticoagulants were relayed with rapid elimination agents (constituting our reference "before" cohort [November 2004-May 2005]), then the antiplatelet or anticoagulant management was continued without stint according to recent data from literature (constituting our "after" cohort (April 2007-March 2008)). RESULTS: a reference population, consisting of 229 patients, was operated on exclusively with "surgical" sub-Tenon's anaesthesia. A second group, consisting of 178 patients, was operated on using "needle" regional anaesthesia. In both populations, nearly 33% of patients received antiplatelet or anticoagulant treatment. The incidence of subconjonctival haemorrhage occurred more frequently when anticoagulants agents were relayed (33% vs 0%; P<0,05), but there was no significant difference with antiplatelet agents (23% vs 8%; NS). The most common non-bleeding event was Chemosis and related to the type of anaesthetic technique utilized, although not serious it tended to jeopardize surgical comfort (anticoagulants: 35% vs 36% (NS), antiplatelet agents: 38% vs 40%; NS). CONCLUSION: the technical changes do not explain fully that occurrence of the HSC, in patients under anticoagulant treatment, decreased in the second period. The achievement of "needle" regional anaesthesia in the anterior segment eye surgery is a safe technique that does not require stopping antiplatelet treatment or anticoagulation.

Cardiac ultrasound and abdominal compartment syndrome.

This review focuses on the available literature published about the evaluation of haemodynamic consequences of the abdominal compartment syndrome (ACS). Animal and clinical studies described decreased venous return, systemic vasoconstriction, systolic and diastolic dysfunction of left and right ventricles. Doppler echocardiography is a non-invasive bedside procedure which provides a complete haemodynamic evaluation of patients with ACS. Despite numerous evaluations in anesthesia during laparoscopic surgery, the use of echocardiography remains scarce in critically ill patients with ACS.

Cardiac ultrasound and abdominal compartment syndrome.

This review focuses on the available literature published about the evaluation of haemodynamic consequences of the abdominal compartment syndrome (ACS). Animal and clinical studies described decreased venous return, systemic vasoconstriction, systolic and diastolic dysfunction of left and right ventricles. Doppler echocardiography is a non-invasive bedside procedure which provides a complete haemodynamic evaluation of patients with ACS. Despite numerous evaluations in anesthesia during laparoscopic surgery, the use of echocardiography remains scarce in critically ill patients with ACS.