M. Biais

Continuous non-invasive arterial pressure measurement: Evaluation of CNAP™ device during vascular surgery

OBJECTIVEnStandard non-invasive blood pressure (BP) monitoring is an intermittent, discontinuous procedure. Beat-to-beat BP monitoring requires invasive measurement via an arterial catheter and may be associated with serious complications. The Infinity CNAP SmartPod (Dräger Medical AG & Co. KG, Lübeck, Germany) has recently been proposed for non-invasive continuous beat-to-beat BP measurements. The present study was designed to compare BP obtained with the CNAP and with an invasive method in the operating room.nnnSTUDY DESIGNnProspective study.nnnPATIENTS AND METHODSnTwenty-five patients undergoing major vascular surgery were included. Systolic, mean and diastolic BP were monitored invasively (SAP, MAP and DAP respectively) and not invasively using the CNAP (CNAP-S, CNAP-M and CNAP-D respectively). Measurements were performed intraoperatively every minute during 1 hour.nnnRESULTSnOne thousand and five hundred pairs of simultaneous CNAP and invasive BP measurements were obtained and 148 were eliminated. The range of BP measurements was 63-205 mmHg for SAP and 57-187 mmHg for CNAP-S, 38-143 mmHg for MAP and 43-142 mmHg for CNAP-M, 29-126 mmHg for DAP and 33-121 mmHg for CNAP-D. Bias and 95% limit of agreement between CNAP and invasive BP measurements were respectively 7.2 and -17.7 to 32.2 mmHg for SAP, -1.8 and -22.0 to 18.3 mmHg for MAP, and -7.5 and -27.3 to 12.4 mmHg for DAP. The percentage of CNAP measurements with a bias <10% with the arterial line was 69%, 86% and 91% for systolic, diastolic and mean pressures, respectively.nnnCONCLUSIONnDespite low accuracy for SAP and DAP measurements, CNAP system seems more accurate for MAP measurement in patients undergoing vascular surgery.

Risk factors for bleeding and transfusion during orthotopic liver transplantation

OBJECTIVEnWhile orthotopic liver transplantation (OLT) can be associated with haemorrhage, the risk factors for bleeding and transfusion remain difficult to predict. Perioperative transfusion has potentially deleterious side effects and impairs graft and patient survival. Preoperative identification of patients at high risk of bleeding is of clinical interest to manage perioperative transfusion and blood product storage.nnnSTUDY DESIGNnRetrospective study.nnnPATIENTS AND METHODSnAll OLT conducted between 2004 and 2008 in the University Hospital of Bordeaux were studied. Risk factors for bleeding greater than one blood volume and for massive red blood cell (RBC) transfusion were determined using univariate and multivariate analysis. Thresholds were determined with ROC curve analysis.nnnRESULTSnOne hundred and forty-eight transplantations were studied. Preoperative haemoglobin and Child class A were independent protective risk factors for bleeding greater than one blood volume (OR 0.81 [0.67-0.98] and 0.27 [0.10-0.72], respectively). Preoperative Hb was a protective risk factor (OR 0.71 [0.58-0.88]) whereas history of oesophageal varicose bleeding was a risk factor (OR 4.67 [1.45-15.05]) for transfusion of more than eight RBC.nnnCONCLUSIONnRisk factors for bleeding and transfusion during OLT identified in this study were of little clinical usefulness so blood products should always be available during the procedure.

Predicting Fluid Responsiveness During Infrarenal Aortic Cross-Clamping in Pigs

OBJECTIVEnInfrarenal aortic cross-clamping (ACC) induces hemodynamic disturbances that may affect respiratory-induced variations in stroke volume and, therefore, affect the ability of dynamic parameters such as pulse-pressure variation (PPV) to predict fluid responsiveness. Since this issue has not been investigated yet to authors knowledge, the hypothesis was tested that ACC may change PPV and impair its ability to predict fluid responsiveness.nnnDESIGNnProspective laboratory experiment.nnnSETTINGnA university research laboratory.nnnPARTICIPANTSnNineteen anesthetized and mechanically ventilated pigs.nnnINTERVENTIONSnTwo courses of volume expansion were performed using 500 mL of saline before and during ACC. Animals were monitored using a systemic arterial catheter, and a pulmonary arterial catheter (stroke volume, central venous pressure, pulmonary arterial occlusion pressure). Animals were defined as responders to volume expansion if stroke volume increased ≥ 15%.nnnRESULTSnBefore ACC, 13 animals were responders. Fluid responsiveness was predicted by a PPV ≥ 14% with a sensitivity of 77% (95% CI = 46%-95%) and a specificity of 83% (95% CI = 36%-97%). The area under the receiver operating characteristic curve was 0.90(95% CI = 0.67-0.99) and was higher than those generated for central venous pressure and pulmonary arterial occlusion pressure. ACC induced an increase in PPV (p<0.0005). During ACC, 8 animals were responders. An 18% PPV threshold discriminated between responders and non-responders to volume expansion, with a sensitivity of 87% (95% CI = 47%-98%) and a specificity of 54% (95% CI = 23%-83%). The area under the receiver operating characteristic curve was 0.72 (95% CI = 0.47-0.90) and was not different from those generated for central venous pressure and pulmonary arterial occlusion pressure.nnnCONCLUSIONSnACC induced a significant increase in PPV and reduced its ability to predict fluid responsiveness.

Dissection coronaire traumatique compliquée d’infarctus du myocarde chez un patient traumatisé crânien

Acute myocardial infarction, following coronary artery dissection, is a rare, but potentially fatal, syndrome after blunt chest trauma. The treatment is more complicated when intracerebral lesions are present, because of the need of anticoagulation. We report the case of a 37-year-old male patient, suffering from a polytraumatism with intracranial petechial haemorrhages who have a left coronary artery dissection with acute myocardial infarction.

Bundle of care for blunt chest trauma patients improves analgesia but increases rates of intensive care unit admission: A retrospective case-control study

INTRODUCTIONnThis single-centre retrospective case-control study aimed to assess the effectiveness of a multidisciplinary clinical pathway for blunt chest trauma patients admitted in emergency department (ED).nnnPATIENTS AND METHODSnAll consecutive blunt chest trauma patients with more than 3 rib fractures and no indication of mechanical ventilation were compared to a retrospective cohort over two 24-month periods, before and after the introduction of the bundle of care. Improvement of analgesia was the main outcome investigated in this study. The secondary outcomes were the occurrence of secondary respiratory complications (pneumonia, indication for mechanical ventilation, secondary ICU admission for respiratory failure or death), the intensive care unit (ICU) and hospital length of stay (LOS).nnnRESULTSnSixty-nine pairs of patients were matched using a 1:1 nearest neighbour algorithm adjusted on age and indices of severity. Between the two periods, there was a significant reduction of the rate of uncontrolled analgesia (55 vs. 17%, P<0.001). A significant increase in the rate of primary ICU transfer during the post-protocol period (23 vs. 52%, P<0.001) was not associated with a reduction of secondary respiratory complications or a reduction of ICU or hospital LOS. Only the use of non-steroidal anti-inflammatory drugs appeared to be associated with a significant reduction of secondary respiratory complications (OR=0.3 [0.1-0.9], P=0.03).nnnCONCLUSIONnImplementation of a multidisciplinary clinical pathway significantly improves pain control after ED management, but increases the rate of primary ICU admission without significant reduction of secondary respiratory complications.

End-expiratory occlusion maneuver to predict fluid responsiveness in the intensive care unit: an echocardiographic study

BackgroundIn mechanically ventilated patients, an increase in cardiac index during an end-expiratory-occlusion test predicts fluid responsiveness. To identify this rapid increase in cardiac index, continuous and instantaneous cardiac index monitoring is necessary, decreasing its feasibility at the bedside. Our study was designed to investigate whether changes in velocity time integral and in peak velocity obtained using transthoracic echocardiography during an end-expiratory-occlusion maneuver could predict fluid responsiveness.MethodsThis single-center, prospective study included 50 mechanically ventilated critically ill patients. Velocity time integral and peak velocity were assessed using transthoracic echocardiography before and at the end of a 12-sec end-expiratory-occlusion maneuver. A third set of measurements was performed after volume expansion (500xa0mL of saline 0.9% given over 15xa0minutes). Patients were considered as responders if cardiac output increased by 15% or more after volume expansion.ResultsTwenty-eight patients were responders. At baseline, heart rate, mean arterial pressure, cardiac output, velocity time integral and peak velocity were similar between responders and non-responders. End-expiratory-occlusion maneuver induced a significant increase in velocity time integral both in responders and non-responders, and a significant increase in peak velocity only in responders. A 9% increase in velocity time integral induced by the end-expiratory-occlusion maneuver predicted fluid responsiveness with sensitivity of 89% (95% CI 72% to 98%) and specificity of 95% (95% CI 77% to 100%). An 8.5% increase in peak velocity induced by the end-expiratory-occlusion maneuver predicted fluid responsiveness with sensitivity of 64% (95% CI 44% to 81%) and specificity of 77% (95% CI 55% to 92%). The area under the receiver operating curve generated for changes in velocity time integral was significantly higher than the one generated for changes in peak velocity (0.96u2009±u20090.03 versus 0.70u2009±u20090.07, respectively, Pu2009=u20090.0004 for both). The gray zone ranged between 6 and 10% (20% of the patients) for changes in velocity time integral and between 1 and 13% (62% of the patients) for changes in peak velocity.ConclusionsIn mechanically ventilated and sedated patients in the neuro Intensive Care Unit, changes in velocity time integral during a 12-sec end-expiratory-occlusion maneuver were able to predict fluid responsiveness and perform better than changes in peak velocity.

Dynamic arterial elastance obtained using arterial signal does not predict an increase in arterial pressure after a volume expansion in the operating room

INTRODUCTIONnDynamic arterial elastance (Eadyn) is defined as the ratio between pulse pressure variations (PPV) and stroke volume variations (SVV). Eadyn has been proposed to predict an increase in mean arterial pressure (MAP) after volume expansion with conflicting results. The aim of the present study was to test the reliability of Eadyn in hypotensive patients (MAP<65mmHg) in the operating room (OR).nnnPATIENTS AND METHODSnThe study pooled data from 51 patients. They were included after the induction of anaesthesia and before skin incision. Eadyn, MAP and stroke volume (FloTrac™, Vigileo™, Edwards Lifesciences, Irvine,CA) were recorded before and after volume expansion (500mL starch 6% given over 10minutes). Pressure-responders were defined as an increase MAP≥15% after volume expansion. Changes in MAP were predicted using the area under the curves (AUC) with their 95% Confidence Interval (95%CI) derived from Receiver Operating Characteristic curves.nnnRESULTSnSeventeen patients responded to volume expansion. Heart rate, PPV, SVV and Eadyn were similar between pressure-responders and non-responders. Baseline values of stroke volume, cardiac output and MAP were lower in responders. Volume expansion induced significant variations in stroke volume, cardiac output, SVV and PPV, but not in Eadyn. Baseline Eadyn failed to predict MAP increase (AUC=0.53, 95%CI=0.36-0.70, P>0.05) and was not correlated with volume expansion-induced changes in MAP (P>0.05). In preload responsive patients (changes in SV≥15% after volume expansion, n=24), the AUC was 0.54 (95%CI=0.29-0.78; P>0.05).nnnCONCLUSIONnIn the present study performed in the OR and in hypotensive patients, Eadyn obtained using arterial signal was unable to predict an increase in MAP after volume expansion.