The future of intensive care: the study of the microcirculation will help to guide our therapies.

The goal of hemodynamic resuscitation is to optimize the microcirculation of organs to meet their oxygen and metabolic needs. Clinicians are currently blind to what is happening in the microcirculation of organs, which prevents them from achieving an additional degree of individualization of the hemodynamic resuscitation at tissue level. Indeed, clinicians never know whether optimization of the microcirculation and tissue oxygenation is actually achieved after macrovascular hemodynamic optimization. The challenge for the future is to have noninvasive, easy-to-use equipment that allows reliable assessment and immediate quantitative analysis of the microcirculation at the bedside. There are different methods for assessing the microcirculation at the bedside; all have strengths and challenges. The use of automated analysis and the future possibility of introducing artificial intelligence into analysis software could eliminate observer bias and provide guidance on microvascular-targeted treatment options. In addition, to gain caregiver confidence and support for the need to monitor the microcirculation, it is necessary to demonstrate that incorporating microcirculation analysis into the reasoning guiding hemodynamic resuscitation prevents organ dysfunction and improves the outcome of critically ill patients.

Impact of platelet transfusion on outcomes in trauma patients.

BACKGROUND: Trauma-induced coagulopathy includes thrombocytopenia and platelet dysfunction that impact patient outcome. Nevertheless, the role of platelet transfusion remains poorly defined. The aim of the study was 1/ to evaluate the impact of early platelet transfusion on 24-h all-cause mortality and 2/ to describe platelet count at admission (PCA) and its relationship with trauma severity and outcome. METHODS: Observational study carried out on a multicentre prospective trauma registry. All adult trauma patients directly admitted in participating trauma centres between May 2011 and June 2019 were included. Severe haemorrhage was defined as ≥ 4 red blood cell units within 6 h and/or death from exsanguination. The impact of PCA and early platelet transfusion (i.e. within the first 6 h) on 24-h all-cause mortality was assessed using uni- and multivariate logistic regression. RESULTS: Among the 19,596 included patients, PCA (229 G/L [189,271]) was associated with coagulopathy, traumatic burden, shock and bleeding severity. In a logistic regression model, 24-h all-cause mortality increased by 37% for every 50 G/L decrease in platelet count (OR 0.63 95% CI 0.57-0.70; p < 0.001). Regarding patients with severe hemorrhage, platelets were transfused early for 36% of patients. Early platelet transfusion was associated with a decrease in 24-h all-cause mortality (versus no or late platelets): OR 0.52 (95% CI 0.34-0.79; p < 0.05). CONCLUSIONS: PCA, although mainly in normal range, was associated with trauma severity and coagulopathy and was predictive of bleeding intensity and outcome. Early platelet transfusion within 6 h was associated with a decrease in mortality in patients with severe hemorrhage. Future studies are needed to determine which doses of platelet transfusion will improve outcomes after major trauma.

Early Recruitment of Cerebral Microcirculation by Neuronal Nitric Oxide Synthase Inhibition in a Juvenile Ischemic Rat Model.

BACKGROUND: The development of collateral circulation is proposed as an inherent compensatory mechanism to restore impaired blood perfusion after ischemia, at least in the penumbra. We have studied the dynamic macro- and microcirculation after ischemia-reperfusion in the juvenile rat brain and evaluated the impact of neuronal nitric oxide synthase (nNOS) inhibition on the collateral flow. METHODS: Fourteen-day-old (P14) rats were subjected to ischemia-reperfusion and treated with either PBS or 7-nitroindazole (7-NI, an nNOS inhibitor, 25 mg/kg). Arterial blood flow (BF) was measured using 2D-color-coded pulsed ultrasound imaging. Laser speckle contrast (LSC) imaging and sidestream dark-field videomicroscopy were used to measure cortical and microvascular BF, respectively. RESULTS: In basal conditions, 7-NI reduced BF in the internal carotids (by ∼ 25%) and cortical (by ∼ 30%) BF, as compared to PBS. During ischemia, the increased mean BF velocity in the basilar trunk after both PBS and 7-NI demonstrated the establishment of collateral support and patency. Upon re-flow, BF immediately recovered to basal values in the internal carotid arteries under both conditions. The 7-NI group showed increased collateral flow in the penumbral tissue during early re-flow compared to PBS, as shown with both LSC imaging and side-stream dark-field videomicroscopy. The proportion of perfused capillaries was significantly increased under 7-NI as compared to PBS when given before ischemia (67.0 ± 3.9 vs. 46.8 ± 8.8, p < 0.01). Perfused capillaries (63.1 ± 17.7 vs. 81.1 ± 20.7, p < 0.001) and the BF index (2.4 ± 0.6 vs. 1.3 ± 0.1, p < 0.001) significantly increased under 7-NI given at the re-flow onset. CONCLUSIONS: Collateral support in the penumbra is initiated during ischemia, and may be increased during early re-flow by neuronal NOS inhibition (given in pre- and post-treatment), which may preserve brain tissue in juvenile rats.

Endotoxin-induced basal respiration alterations of renal HK-2 cells: a sign of pathologic metabolism down-regulation.

To study the mechanism of oxygen regulation in inflammation-induced acute kidney injury, we investigate the effects of a bacterial endotoxin (lipopolysaccharide, LPS) on the basal respiration of proximal tubular epithelial cells (HK-2) both by high-resolution respirometry and electron spin resonance spectroscopy. These two complementary methods have shown that HK-2 cells exhibit a decreased oxygen consumption rate when treated with LPS. Surprisingly, this cellular respiration alteration persists even after the stress factor was removed. We suggested that this irreversible decrease in renal oxygen consumption after LPS challenge is related to a pathologic metabolic down-regulation such as a lack of oxygen utilization by cells.

Cytokine response and reactive oxygen species production after low- and intermediate-risk surgery.

BACKGROUND: Cytokines are secreted locally in response to surgery and may be released into the systemic circulation. Reactive oxygen species (ROS) production is involved in various inflammatory conditions. The aims of the study were to examine the magnitude of surgical stress on the modulation of immune response and ROS production. METHODS: Patients undergoing low- and intermediate-risk surgery (n=32) were enrolled. Blood samples for tumor necrosis factor (TNF)α, interleukin (IL)1ß and IL10 assays were obtained before anesthesia, immediately after extubation, at 24 and 72 h after surgery. Measurement in whole-blood cultures of ex vivo lipopolysaccharide (LPS) and Staphylococcus aureus Cowan (SAC)-stimulated production of cytokines was carried out. The pro-oxidant potency of the whole serum was assessed in human umbilical vein endothelial cells using a fluorescent probe after stimulation by the plasma collected at the same time intervals. RESULTS: TNFα, IL1ß and IL10 did not increase significantly after surgery in either group. Whole-blood cultures response to LPS and SAC stimulation decreased for IL1ß at the end of surgery in the two groups and returned to normal within 24 h after surgery. LPS- and SAC-induced IL10 production increased significantly at 24 h in the low-risk surgery group. ROS production was greater after more stressful surgery and was correlated to morphine consumption. CONCLUSION: Cytokine release in the systemic circulation was not well correlated to the magnitude of surgical stress, whereas transient immune hyporesponsiveness was seen after moderately stressful surgery. ROS production might be a more accurate indicator of the severity of surgical trauma.

French recommendations for the management of patients with spinal cord injury or at risk of spinal cord injury.

OBJECTIVES: To update the French guidelines on the management of trauma patients with spinal cord injury or suspected spinal cord injury. DESIGN: A consensus committee of 27 experts was formed. A formal conflict-of-interest (COI) policy was developed at the outset of the process and enforced throughout. The entire guidelines process was conducted independently of any industrial funding (i.e. pharmaceutical, medical devices). The authors were advised to follow the rules of the Grading of Recommendations Assessment, Development and Evaluation (GRADE®) system to guide assessment of quality of evidence. The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasised. METHODS: The committee studied twelve questions: (1) What are the indications and arrangements for spinal immobilisation? (2) What are the arrangements for pre-hospital orotracheal intubation? (3) What are the objectives of haemodynamic resuscitation during the lesion assessment, and during the first few days in hospital? (4) What is the best way to manage these patients to improve their long-term prognosis? (5) What is the place of corticosteroid therapy in the initial phase? (6) What are the indications for magnetic resonance imaging in the lesion assessment phase? (7) What is the optimal time for surgical management? (8) What are the best arrangements for orotracheal intubation in the hospital environment? (9) What are the specific conditions for weaning these patients from mechanical ventilation for? (10) What are the procedures for analgesic treatment of these patients? (11) What are the specific arrangements for installing and mobilising these patients? (12) What is the place of early intermittent bladder sampling in these patients? Each question was formulated in a PICO (Patients, Intervention, Comparison, Outcome) format and the evidence profiles were produced. The literature review and recommendations were made according to the GRADE® Methodology. RESULTS: The experts' work synthesis and the application of the GRADE method resulted in 19 recommendations. Among the recommendations formalised, 2 have a high level of evidence (GRADE 1+/-) and 12 have a low level of evidence (GRADE 2+/-). For 5 recommendations, the GRADE method could not be applied, resulting in expert advice. After two rounds of scoring and one amendment, strong agreement was reached on all the recommendations. CONCLUSIONS: There was significant agreement among experts on strong recommendations to improve practices for the management of patients with spinal cord injury.

Comparison of two versions of the Vigileo-FloTrac system (1.03 and 1.07) for stroke volume estimation: a multicentre, blinded comparison with oesophageal Doppler measurements.

BACKGROUND: Our aim was to evaluate the validity of stroke volume measurements obtained using the Vigileo-FloTrac system in comparison with those obtained using oesophageal Doppler considered as a reference. METHODS: Prospective, multicentre study (four university hospitals), in which investigators were blinded to stroke volume values acquired simultaneously with the other technique. Two different versions of the Vigileo software (1.03 and 1.07) were studied and compared over two consecutive periods of time. Forty critically ill patients (three ICUs) and 20 high-risk surgical patients (one operating theatre) were studied over a 6-month period. RESULTS: Two hundred and forty paired stroke volume values obtained using the second version of the Vigileo (1.07) yielded better correlation and agreement (R=0.48, P<0.001; bias=4 ml, limits of agreement: +/- 41 ml) than the 207 paired values obtained using version 1.03 (R=0.12, P=0.1; bias=1 ml, limits of agreement: +/- 75 ml). However, even with the second version, the percentage error in stroke volume measurement was 58%, a value still above the range considered clinically acceptable (30%). CONCLUSIONS: The precision of stroke volume estimation using Vigileo-FloTrac has improved with the second version of the software (1.07), but remains insufficient to allow the replacement of the reference technique in the population studied.

Correction to: Serum sodium and intracranial pressure changes after desmopressin therapy in severe traumatic brain injury patients: a multi-centre cohort study.

Following publication of the original article [1], we were notified that the collaborators' names part of the "The TBI Collaborative" group has not been indexed in Pubmed. Below the collaborators names full list.

Serum sodium and intracranial pressure changes after desmopressin therapy in severe traumatic brain injury patients: a multi-centre cohort study.

BACKGROUND: In traumatic brain injury (TBI) patients desmopressin administration may induce rapid decreases in serum sodium and increase intracranial pressure (ICP). AIM: In an international multi-centre study, we aimed to report changes in serum sodium and ICP after desmopressin administration in TBI patients. METHODS: We obtained data from 14 neurotrauma ICUs in Europe, Australia and UK for severe TBI patients (GCS ≤ 8) requiring ICP monitoring. We identified patients who received any desmopressin and recorded daily dose, 6-hourly serum sodium, and 6-hourly ICP. RESULTS: We studied 262 severe TBI patients. Of these, 39 patients (14.9%) received desmopressin. Median length of treatment with desmopressin was 1 [1-3] day and daily intravenous dose varied between centres from 0.125 to 10 mcg. The median hourly rate of decrease in serum sodium was low (- 0.1 [- 0.2 to 0.0] mmol/L/h) with a median period of decrease of 36 h. The proportion of 6-h periods in which the rate of natremia correction exceeded 0.5 mmol/L/h or 1 mmol/L/h was low, at 8% and 3%, respectively, and ICPs remained stable. After adjusting for IMPACT score and injury severity score, desmopressin administration was independently associated with increased 60-day mortality [HR of 1.83 (1.05-3.24) (p = 0.03)]. CONCLUSIONS: In severe TBI, desmopressin administration, potentially representing instances of diabetes insipidus is common and is independently associated with increased mortality. Desmopressin doses vary markedly among ICUs; however, the associated decrease in natremia rarely exceeds recommended rates and median ICP values remain unchanged. These findings support the notion that desmopressin therapy is safe.

[Transcranial doppler in neurosurgery]. / Le doppler transcrânien en neurochirurgie.

Transcranial doppler (TCD) is a noninvasive and easily repeatable method to measure the blood flow in basal cerebral arteries. Mean velocities of red blood cells in basal arteries are related to cerebral blood flow. Because of low peripheral resistance in cerebral arteries, diastolic velocity (V(d)) remains positive in cerebral circulation in physiological situations. The pulsativity index (PI; normal values for the middle cerebral artery=1.0+/-0.2) and end diastolic velocity (EDV; normal values for the middle cerebral artery=40+/-10 cm/s) give important information to evaluate the resistance status of small downstream arteries. A high PI (>1.4) with a low EDV (<20 cm/s) indicates a low blood flow with a high ischemic risk due to low cerebral perfusion pressure. TCD can also detect cerebral vasospasm after subarachnoid hemorrhage, but sensitivity and specificity for vasospasm diagnosis are low compared to angiography. However, a day-to-day increase in arterial blood cell velocities can help determine the vasospasm risk and/or indicate that angiography should be done.

Femoral arterial and central venous catheters in the trauma resuscitation room.

BACKGROUND: Arterial and central venous femoral catheters (fAC-CVC) use during the initial management of severe trauma patients is not a standard technique in most trauma centers. Arguments in favor of their use are: continuous monitoring of blood pressure, safe drug administration, easy blood sampling and potentially large bore venous access. The lack of evidence makes the practice heterogeneous. The aim of the present study was to describe the use and complications of fAC-CVC in the trauma bay in two centers where they are routinely used. METHODS: This was a retrospective analysis of routine fAC-CVC use from two French trauma centers. All patients admitted directly to the trauma resuscitation room were included. Demographic, clinical and biological data were collected from the scene to discharge to describe the use of catheters during initial trauma management including infectious, mechanical and thrombotic complications. RESULTS: 243 pairs of femoral catheters were inserted among 692 patients admitted in both trauma centers. Femoral AC-CVC use was more frequent in critically ill patients with higher ISS 26 [17; 41] vs 13 [8; 24], p < 0.001(median [quartile 1-3]), severe traumatic brain injury (AIS head 1[0-4] vs 0[0-3], p < 0.001), lower systolic blood pressure, 92 (37) vs 113 (28) mmHg, p < 0.001 mean (standard deviation), lower haemoglobin on arrival, 10.9 (3) vs 13.3 (2.1) g/dL (p < 0.001), and higher blood lactate concentration, 4.0 (3.9) vs 2.1 (1.8) mmol/L (p < 0.001). In patients with fAC-CVC use time in the trauma room was longer, 46 [40;60] vs 30 [20;40] minutes (p < 0.05). In total 52 colonizations and 3 bloodstream infections were noted in 1000 catheter days. An incidence of 12% of mechanical complications and of 42% deep venous thromboses were observed. Of the latter none was associated with confirmed pulmonary embolism. CONCLUSION: Femoral AC-CVC appeared to be deployed more often in critically ill patients, presenting with shock and/or traumatic brain injury in particular. The observed rate of complications in this sample seems to be low compared to reported rates.

How useful are hemoglobin concentration and its variations to predict significant hemorrhage in the early phase of trauma? A multicentric cohort study.

BACKGROUND: The diagnostic value of hemoglobin (Hb) for detecting a significant hemorrhage (SH) in the early phase of trauma remains controversial. The present study aimed to assess the abilities of Hb measurements taken at different times throughout trauma management to identify patients with SH. METHODS: All consecutive adult trauma patients directly admitted to six French level-1 trauma centers with at least one prehospital Hb measurement were analyzed. The abilities of the following variables to identify SH (≥ 4 units of red blood cells in the first 6 h and/or death related to uncontrolled bleeding within 24 h) were determined and compared to that of shock index (SI): Hb as measured with a point-of-care (POC) device by the prehospital team on scene (POC-Hbprehosp) and upon patient's admission to the hospital (POC-Hbhosp), the difference between POC-Hbhosp and POC-Hbprehosp (DeltaPOC-Hb) and Hb as measured by the hospital laboratory on admission (Hb-Labhosp). RESULTS: A total of 6402 patients were included, 755 with SH and 5647 controls (CL). POC-Hbprehosp significantly predicted SH with an area under ROC curve (AUC) of 0.72 and best cutoff values of 12 g/dl for women and 13 g/dl for men. POC-Hbprehosp < 12 g/dl had 90% specificity to predict of SH. POC-Hbhosp and Hb-Labhosp (AUCs of 0.92 and 0.89, respectively) predicted SH better than SI (AUC = 0.77, p < 0.001); best cutoff values of POC-Hbhosp were 10 g/dl for women and 12 g/dl for men. DeltaPOC-Hb also predicted SH with an AUC of 0.77, a best cutoff value of - 2 g/dl irrespective of the gender. For a same prehospital fluid volume infused, DeltaPOC-Hb was significantly larger in patients with significant hemorrhage than in controls. CONCLUSIONS: Challenging the classical idea that early Hb measurement is not meaningful in predicting SH, POC-Hbprehosp was able, albeit modestly, to predict significant hemorrhage. POC-Hbhosp had a greater ability to predict SH when compared to shock index. For a given prehospital fluid volume infused, the magnitude of the Hb drop was significantly higher in patients with significant hemorrhage than in controls.

High level of venous thromboembolism in critically ill trauma patients despite early and well-driven thromboprophylaxis protocol.

BACKGROUND: Venous thromboembolism (VTE) is one of the most common preventable causes of in-hospital death in trauma patients surviving their injuries. We assessed the prevalence, incidence and risk factors for deep venous thrombosis (DVT) and pulmonary embolism (PE) in critically ill trauma patients, in the setting of a mature and early mechanical and pharmacological thromboprophylaxis protocol. METHODS: This was a prospective observational study on a cohort of patients from a surgical intensive care unit of a university level 1 trauma centre. We enrolled consecutive primary trauma patients expected to be in intensive care for ≥48 h. Thromboprophylaxis was protocol driven. DVT screening was performed by duplex ultrasound of upper and lower extremities within the first 48 h, between 5 and 7 days and then weekly until discharge. We recorded VTE risk factors at baseline and on each examination day. Independent risk factors were analysed using a multivariate logistic regression. RESULTS: In 153 patients with a mean Injury Severity Score of 23 ± 12, the prevalence of VTE was 30.7%, 95 CI [23.7-38.8] (29.4% DVT and 4.6% PE). The incidence was 18%, 95 CI [14-24] patients-week. The median time of apparition of DVT was 6 days [1; 4]. The global protocol compliance was 77.8% with a median time of introduction of the pharmacological prophylaxis of 1 day [1; 2]. We identified four independent risk factors for VTE: central venous catheter (OR 4.39, 95 CI [1.1-29]), medullar injury (OR 5.59, 95 CI [1.7-12.9]), initial systolic arterial pressure <80 mmHg (OR 3.64, 95 CI [1.3-10.8]), and pelvic fracture (OR 3.04, 95 CI [1.2-7.9]). CONCLUSION: Despite a rigorous, protocol-driven thromboprophylaxis, critically ill trauma patients showed a high incidence of VTE. Further research is needed to tailor pharmacological prophylaxis and balance the risks and benefits.

Left ventricular function after severe trauma.

OBJECTIVE: To evaluate cardiac function at the early phase of severe trauma. DESIGN: Prospective, clinical study. SETTING: Anesthesiological Intensive Care Unit. PATIENTS: 7 consecutive patients admitted after severe trauma (ISS: 38 +/- 9, mean +/- SD), without preexisting cardiac disease. INTERVENTIONS: Each patient received midazolam and sufentanyl for sedation. Right heart catheterization (Swan-Ganz) and transesophageal echocardiography (TEE) were performed. The fractional area change (FAC) of the left ventricle was calculated within 6 h following trauma and at day 1 and day 2 in order to evaluate left ventricular function. MEASUREMENTS AND RESULTS: All of the patients had a low FAC value < 50% at day 0 (43.2 +/- 2.4%, range 39-46%), which increased significantly at day 2 (52.5 +/- 4%, range 47-59%, p = 0.001), whereas heart rate and preload (assessed by left ventricular end diastolic area and pulmonary arterial occlusion pressure) were constant and afterload, assessed by systolic blood pressure, increased significantly between day 0 and day 2 (112 +/- 21 to 145 +/- 24 mmHg, p = 0.02). CONCLUSION: The initial phase of severe trauma is associated with an abnormal cardiac function, suggested by a low FAC value. This myocardial dysfunction must be taken into account for early resuscitation after severe injury.

Heterogeneous regional vascular responses to simulated transient hypovolemia in man.

OBJECTIVE: To describe the evolution of systemic and regional blood flows during and after hypovolemia in humans. DESIGN: Simulation of hypovolemia by a prolonged application of lower body negative pressure (LBNP). SETTING: Laboratory of Clinical Research, Surgical Intensive Care Unit of an University Hospital. PARTICIPANTS: 8 healthy male volunteers. INTERVENTIONS: 3 successive and increasing 15 min-levels of LBNP were followed by a progressive return (10 min) to atmospheric pressure, then a 60 min-recovery period. MEASUREMENTS AND MAIN RESULTS: Simulated hypovolemia induced a parallel one-third decrease in cardiac output (bioimpedance), musculocutaneous (venous plethysmography) and splanchnic (ICG clearance) blood flows. Adrenergic-mediated peripheral vasoconstriction prevented any change in mean arterial pressure. The decrease in renal blood flow (PAH clearance) was limited, glomerular filtration rate (inulin clearance) unchanged and thus filtration fraction increased. All the cardiovascular and biological variables returned to pre-LBNP values during the recovery period except for splanchnic blood flow which remained below control values 60 min after the return to atmospheric pressure. CONCLUSIONS: Since a sustained splanchnic vasoconstriction follows a transient normotensive hypovolemia in healthy men despite adequate treatment considering arterial pressure and cardiac output, the therapeutic goals of fluid resuscitation after hypovolemic shock might be revisited and a supranormal value of cardiac output proposed.

Effects of tidal volume reduction in acute respiratory distress syndrome on gastric mucosal perfusion.

OBJECTIVE: This study was conducted with the aim of testing the effects of a reduction in tidal volume (V(T)) on gastric mucosal perfusion using laser-Doppler flowmetry in patients with acute respiratory distress syndrome (ARDS). DESIGN: It was designed as a prospective study. PATIENTS: Seventeen patients with ARDS were enrolled in the study. All patients were mechanically ventilated in volume-controlled mode. Before the start of the protocol, V(T) was set at 9 ml/kg body weight. INTERVENTION: V(T) was reduced to 6 ml/kg body weight. MEASUREMENTS AND RESULTS: Measurements of systemic hemodynamic parameters and gastric mucosal blood flow (GMBF) were obtained before and after reduction of V(T). Cardiac index, heaart rate and pulmonary arterial pressure increased significantly after V(T) reduction. The increase in cardiac output was observed in all patients. However, despite a mean 25% increase in cardiac output after V(T) reduction, no significant increase in mean GMBF was observed, and individual GMBF responses were heterogeneous. CONCLUSION: V(T) reduction in patients with ARDS, despite resulting in an increase in cardiac output, did not change gastric mucosal perfusion. The heterogeneity in the individual response of GMBF to V(T) reduction could be due to opposite direct (i.e., local vasodilatory effect) and indirect (i.e., global sympathetic stimulation) effects of hypercapnia on gut vessels.

Transgastric, pulsed Doppler echocardiographic determination of cardiac output.

OBJECTIVE: The aim of this study was to evaluate the accuracy of cardiac output measurement with transesophageal echocardiography (TEE) using a transgastric, pulsed Doppler method in acutely ill patients. DESIGN: Cardiac output was simultaneously measured by thermodilution (TD) and a transgastric, pulsed Doppler method. SETTING: The study was carried out in a surgical intensive care unit as part of the management protocol of the patients. PATIENTS: Thirty consecutive acutely ill patients with a Swan-Ganz catheter, mechanically ventilated, sedated and with a stable hemodynamic condition were included. MEASUREMENTS: Pulsed Doppler TEE was performed using a transgastric approach in order to obtain a long axis view of the left ventricle. Cardiac output was calculated from the left ventricular outflow tract diameter, the velocity time integral of the blood flow profile and heart rate. RESULTS: One patient was excluded because of the presence of aortic regurgitation and another, because of the impossibility of obtaining a transgastric view. Twenty-eight simultaneous measurements were performed in 28 patients. A clinically acceptable correlation and agreement were found between the two methods (Doppler cardiac output = 0.889 thermodilution cardiac output +0.74 l/min, r = 0.975, p <0.0001). CONCLUSION: Transgastric pulsed Doppler measurement across the left ventricular outflow tract with TEE is a very feasible and clinically acceptable method for cardiac output measurement in acutely ill patients.

Role of systemic inflammatory response syndrome and infection in the occurrence of early multiple organ dysfunction syndrome following severe trauma.

OBJECTIVE: To evaluate the role of infection and systemic inflammatory response syndrome (SIRS) on the occurrence of early posttraumatic MODS. DESIGN: Retrospective study. SETTING: University Teaching Hospital ICU. PATIENTS: 163 consecutive patients hospitalized for more than 48 hours following severe trauma. MEASUREMENTS AND MAIN RESULTS: The patients were classified into two groups in respect to the existence of MODS at day 2. There was 27 patients in the MODS group and 136 patients in the no MODS group. The two groups were similar with respect to age, sex ratio and Simplified Acute Physiology Score. The MODS group had a higher mortality (52 versus 7%), Injury Severity Score (45 +/- 14 versus 31 +/- 13), hypovolemic shock rate (74 versus 30%), massive volume replacement rate (59 versus 6%) and SIRS rate (81 versus 54%) than the no MODS group (P < 0.05). The rate of infection was similarly low in the MODS and no MODS group (4 versus 6% respectively). CONCLUSION: Early MODS is often associated with hypotension and massive volume administration but very rarely with infection, despite the high rate of SIRS.

Baroreflex control of regional vascular resistances during simulated orthostatism.

Orthostatic stress or moderate hypovolemia was simulated in 10 healthy volunteers by the lower body negative pressure technique (LBNP at -10, -20 and -40 mm Hg). LBNP induced a progressive and parallel decrease in central venous pressure and cardiac output but mean arterial pressure remained unchanged regardless of the LBNP level. Heart rate and pulse pressure were only significantly increased and decreased at LBNP -40 mm Hg, respectively, indicating that cardiopulmonary baroreflexes were selectively deactivated up to LBNP -20 mm Hg, whereas both cardiopulmonary and arterial baroreflexes were deactivated at LBNP -40 mm Hg. The LBNP-induced increase in total peripheral resistance was heterogeneously distributed within the body. Forearm vasoconstriction occurred at low levels of LBNP and was exclusively related to an increase in sympathetic tone. Splanchnic vasoconstriction also occurred at low levels of LBNP, but was related to activation in sympathetic and renin-angiotensin systems. Renal vasoconstriction occurred mainly at high levels of LBNP (-40 mm Hg), but glomerular filtration rate and filtration fraction increased at low levels of LBNP (-10 mm Hg). Thus, if renal vascular resistance is not of major importance for the control of blood pressure during orthostatism or moderate hypovolemia, neurohumoral mechanisms triggered through deactivation of cardiopulmonary receptors play a key role in the maintenance of intrarenal homeostasis associated with reduction in cardiac filling pressure.