Scorpion envenomation: state of the art.

Scorpion envenomation is common in the tropical and subtropical regions. It poses a major public health problem with some patients having serious clinical manifestations and severe complications including death. Old World and New World scorpions are usually contrasted because of differences in venom composition, clinical presentation and severity, and, accordingly, different therapeutic approaches. The majority of scorpion stings are either dry or result in low amounts of injected venom, thus explaining why up to 95% of scorpion stings ensue only in local signs. For a clinical envenomation to occur, it has been suggested that the interaction between the quantity of venom introduced in the body of the prey and the distribution volume should ensue in a critical threshold of scorpion toxin plasma concentration. In this case, there is a massive release of neurohormonal mediators (mainly catecholamine), with systemic vasoconstrictor effects eliciting a sharp increase in systemic arterial pressure and LV-filling pressure and decreased cardiac output. This early phase of cardiac dysfunction, also called "vascular phase", is followed by a severe cardiomyopathy, a form of Takotsubo cardiomyopathy, involving both ventricles and reversible in days to weeks. The more comprehensive understanding of the disease pathophysiology has allowed for a well-codified symptomatic treatment, thus contributing to a substantial reduction in the death toll of scorpion envenomation over the past few decades. The standard intensive-care treatment (when available) overcomes envenomation's consequences such as acute pulmonary edema and cardiogenic shock. Even though it continues to inspire many evaluative studies, immunotherapy seems less attractive because of the major role held by mediators in the pathogenesis of envenomation, and unfavorable pharmacokinetic properties to existing sera compared to venom. Meta-analyses of controlled trials of immunotherapy in severe scorpion envenomation reached similar conclusions: there is an acceptable level of evidence in favor of the use of scorpion antivenom (Fab'2) against Centruroides sp. in USA/Mexico, while there is still a need for a higher level of evidence for immunotherapy in the Old World envenomation.

Incidence and Impact of Pulmonary Embolism During Severe COPD Exacerbation.

BACKGROUND: Patients with COPD are at a high risk for pulmonary embolism (PE) because of systemic inflammation and co-existing comorbidities. We aimed to determine the incidence, risk factors, and impact of PE during COPD exacerbation requiring mechanical ventilation. METHODS: This prospective cohort study was conducted between March 2013 and May 2017. Subjects with severe COPD exacerbation requiring mechanical ventilation were included. A lower-limb ultrasonography or a multidetector helical computed tomography scan (MDCT) was performed according to Wells score. Subjects with ultrasonographic signs of phlebitis underwent MDCT to confirm PE. RESULTS: During the study period, 131 COPD subjects were admitted to the ICU for severe COPD exacerbation. The incidence of PE was 13.7%. Factors independently associated with PE were increased sputum volume (odds ratio [OR] = 0.106, 95% CI 0.029-0.385, P = .001), recent immobilization ≥ 7 d (OR = 5.024, 95% CI 1.470-17.170, P = .01), age ≥ 70 y (OR = 5.483, 95% CI 1.269-23.688, P = .02), and invasive mechanical ventilation at ICU admission (OR = 3.615, 95% CI 1.005-13.007, P = .049). ICU mortality was higher in the PE group (44% vs 11%). Predictive factors of mortality were PE (OR = 7.135, 95% CI 2.042-24.931, P = .002), SAPS II score at admission OR = 1.040, 95% CI 1.005-1.077, P = .02), and duration of mechanical ventilation (OR = 1.098, 95% CI 1.044-1.154, P < .001). CONCLUSION: PE was found to be a common etiology of severe exacerbation of COPD, leading to high mortality. Age, invasive mechanical ventilation, and immobilization were risk factors for PE.

Comparison Between Continuous and Intermittent Administration of Hydrocortisone During Septic Shock: A Randomized Controlled Clinical Trial.

OBJECTIVES: The best modality of administration of hydrocortisone during septic shock has been poorly evaluated and the guidelines remain unclear in this respect. This study aimed to compare bolus of hydrocortisone to a continuous infusion during septic shock. DESIGN: Randomized controlled, open-label trial. SETTING: Medical ICU of a university hospital. PATIENTS: Adult patients with septic shock requiring more than 2 mg/h (approximately 33.3 µg/mn) of norepinephrine after adequate fluid administration were eligible.Patients already receiving corticosteroids or who have a contraindication to corticosteroids, patients who died within 24 h and those with a decision of not to resuscitate were excluded. INTERVENTIONS: Patients were randomized either to receive hydrocortisone 200 mg/d by continuous infusion or by boluses of 50 mg every 6 h throughout the prescription of vasopressors with a maximum of 7 days. RESULTS: Twenty-nine patients were included in each group. Shock reversal was significantly higher in the HC bolus group (66% vs. 35%, P = 0.008). The median time to shock reversal was 5 days (95% CI, 4.31-5.69) in the HC bolus group compared to 6 days (95% CI, 4.80-7.19) in the HC continuous infusion group (log Rank = 0.048). The number of hours spent with blood glucose ≥ 180 mg/dL was higher in the HC continuous infusion group with a median of 64 h [IQR (2-100)] versus 48 h [IQR (14-107)] in the HC bolus group, (P = 0.60), and daily insulin requirements were similar between the two groups (P = 0.63). The occurrence of other side effects, mortality, and ICU LOS were similar between the study groups. CONCLUSION: Hydrocortisone administered by intermittent bolus was associated with higher shock reversal at day 7 compared with a continuous infusion.

Haemodynamic response to crystalloids or colloids in shock: an exploratory subgroup analysis of a randomised controlled trial.

OBJECTIVE: To compare the haemodynamic effect of crystalloids and colloids during acute severe hypovolaemic shock. DESIGN: Exploratory subgroup analysis of a multicentre randomised controlled trial (Colloids Versus Crystalloids for the Resuscitation of the Critically Ill, CRISTAL, ClinicalTrials.gov NCT00318942). SETTING: CRISTAL was conducted in intensive care units in Europe, North Africa and Canada. PARTICIPANTS: Current analysis included all patients who had a pulmonary artery catheter in place at randomisation. 220 patients (117 received crystalloids vs 103 colloids) underwent pulmonary artery catheterisation. INTERVENTION: Crystalloids versus colloids for fluid resuscitation in hypovolaemic shock. OUTCOME MEASURES: Haemodynamic data were collected at the time of randomisation and subsequently on days 1, 2, 3, 4, 5, 6 and 7. RESULTS: Median cumulative volume of fluid administered during the first 7 days was higher in the crystalloids group than in the colloids group (3500 (2000-6000) vs 2500 (1000-4000) mL, p=0.01). Patients in the colloids arm exhibited a lower heart rate over time compared with those allocated to the crystalloids arm (p=0.014). There was no significant difference in Cardiac Index (p=0.053), mean blood pressure (p=0.4), arterial lactates (p=0.9) or global Sequential Organ Failure Assessment score (p=0.3) over time between arms. CONCLUSIONS: During acute severe hypovolaemic shock, patients monitored by a pulmonary artery catheter achieved broadly similar haemodynamic outcomes, using lower volumes of colloids than crystalloids. The heart rate was lower in the colloids arm.

Study of severe scorpion envenoming following subcutaneous venom injection into dogs: Hemodynamic and concentration/effect analysis.

To evaluate the dose-effects of Androctonus australis hector (Aah) venom injected subcutaneously on hemodynamics and neurohormonal secretions, 10 anesthetized and ventilated mongrel dogs, were split in two groups (n = 5/group). Subcutaneous injection was done with either 0.2 mg/kg or 0.125 mg/kg of the purified G50 scorpion toxic fraction. Hemodynamic parameters using right heart catheter were recorded and plasma concentrations of catecholamine, troponin, and serum toxic fraction were measured sequentially from baseline to 120 min. We identified the dose of toxic fraction evoking characteristic hemodynamic perturbation of severe envenomation, the time-lapse to envenomation, and the associated plasma level. The injection of 0.125 mg/kg toxic fraction was not associated with significant variations in hemodynamic parameters, whereas the 0.2 mg/kg dose caused envenomation characterized by significant increase in plasma catecholamines, increased pulmonary artery occluded pressure, mean arterial pressure, and systemic vascular resistance (p < 0.05), in association with sustained decline in cardiac output (p < 0.001). Envenomation occurred by the 30th minute, and the corresponding concentration of toxic fraction was 1.14 ng/ml. The current experiment allowed the identification of the sub-lethal dose (0.2 mg/kg) of the toxic fraction of Aah administered by the subcutaneous route. Two parameters with potential clinical relevance were also uncovered: the time-lapse to envenomation and the corresponding concentration of toxic fraction.

Prednisone in COPD exacerbation requiring ventilatory support: an open-label randomised evaluation.

Recommendation of the use of systemic steroids in chronic obstructive disease (COPD) exacerbation rely on trials that excluded patients requiring ventilatory support. In an open-label, randomised evaluation of oral prednisone administration, 217 patients with acute COPD exacerbation requiring ventilatory support were randomised (with stratification on the type of ventilation) to usual care (n=106) or to receive a daily dose of prednisone (1 mg·kg(-1)) for up to 10 days (n=111). There was no difference regarding the primary end-point, intensive care unit mortality, which was 17 (15.3%) deaths versus 15 (14%) deaths in the steroid-treated and control groups, respectively (relative risk 1.08, 95% CI 0.6-2.05). Analysis according to ventilation modalities showed similar mortality rates. Noninvasive ventilation failed in 15.7% and 12.7% (relative risk 1.25, 95% CI 0.56-2.8; p=0.59), respectively. Both study groups had similar median mechanical ventilation duration and intensive care unit length of stay, which were 6 (interquartile range 6-12) days versus 6 (3.8-12) days and 9 (6-14) days versus 8 (6-14) days, respectively. Hyperglycaemic episodes requiring initiation or alteration of current insulin doses occurred in 55 (49.5%) patients versus 35 (33%) patients in the prednisone and control groups, respectively (relative risk 1.5, 95% CI 1.08-2.08; p=0.015). Prednisone did not improve intensive care unit mortality or patient-centred outcomes in the selected subgroup of COPD patients with severe exacerbation but significantly increased the risk of hyperglycaemia.

Effects of fluid resuscitation with colloids vs crystalloids on mortality in critically ill patients presenting with hypovolemic shock: the CRISTAL randomized trial.

IMPORTANCE: Evidence supporting the choice of intravenous colloid vs crystalloid solutions for management of hypovolemic shock remains unclear. OBJECTIVE: To test whether use of colloids compared with crystalloids for fluid resuscitation alters mortality in patients admitted to the intensive care unit (ICU) with hypovolemic shock. DESIGN, SETTING, AND PARTICIPANTS: A multicenter, randomized clinical trial stratified by case mix (sepsis, trauma, or hypovolemic shock without sepsis or trauma). Therapy in the Colloids Versus Crystalloids for the Resuscitation of the Critically Ill (CRISTAL) trial was open label but outcome assessment was blinded to treatment assignment. Recruitment began in February 2003 and ended in August 2012 of 2857 sequential ICU patients treated at 57 ICUs in France, Belgium, North Africa, and Canada; follow-up ended in November 2012. INTERVENTIONS: Colloids (n = 1414; gelatins, dextrans, hydroxyethyl starches, or 4% or 20% of albumin) or crystalloids (n = 1443; isotonic or hypertonic saline or Ringer lactate solution) for all fluid interventions other than fluid maintenance throughout the ICU stay. MAIN OUTCOMES AND MEASURES: The primary outcome was death within 28 days. Secondary outcomes included 90-day mortality; and days alive and not receiving renal replacement therapy, mechanical ventilation, or vasopressor therapy. RESULTS: Within 28 days, there were 359 deaths (25.4%) in colloids group vs 390 deaths (27.0%) in crystalloids group (relative risk [RR], 0.96 [95% CI, 0.88 to 1.04]; P = .26). Within 90 days, there were 434 deaths (30.7%) in colloids group vs 493 deaths (34.2%) in crystalloids group (RR, 0.92 [95% CI, 0.86 to 0.99]; P = .03). Renal replacement therapy was used in 156 (11.0%) in colloids group vs 181 (12.5%) in crystalloids group (RR, 0.93 [95% CI, 0.83 to 1.03]; P = .19). There were more days alive without mechanical ventilation in the colloids group vs the crystalloids group by 7 days (mean: 2.1 vs 1.8 days, respectively; mean difference, 0.30 [95% CI, 0.09 to 0.48] days; P = .01) and by 28 days (mean: 14.6 vs 13.5 days; mean difference, 1.10 [95% CI, 0.14 to 2.06] days; P = .01) and alive without vasopressor therapy by 7 days (mean: 5.0 vs 4.7 days; mean difference, 0.30 [95% CI, -0.03 to 0.50] days; P = .04) and by 28 days (mean: 16.2 vs 15.2 days; mean difference, 1.04 [95% CI, -0.04 to 2.10] days; P = .03). CONCLUSIONS AND RELEVANCE: Among ICU patients with hypovolemia, the use of colloids vs crystalloids did not result in a significant difference in 28-day mortality. Although 90-day mortality was lower among patients receiving colloids, this finding should be considered exploratory and requires further study before reaching conclusions about efficacy. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00318942.

N-terminal proB-type natriuretic peptide levels aid the diagnosis of left ventricular dysfunction in patients with severe acute exacerbations of chronic obstructive pulmonary disease and renal dysfunction.

BACKGROUND AND OBJECTIVE: The aim of this study was to assess the performance of N-terminal proB-type natriuretic peptide (NT-proBNP) levels for the diagnosis of left ventricular dysfunction in patients with severe acute exacerbations of chronic obstructive pulmonary disease (COPD) and renal dysfunction. METHODS: NT-proBNP levels at admission were measured in consecutive patients admitted to two participating intensive care units with acute exacerbations of COPD. Left ventricular dysfunction was assessed on the basis of clinical and echocardiographic criteria. The performance of NT-proBNP levels was evaluated in patients with or without renal dysfunction. RESULTS: Among the 120 patients included in the study, 70 had impaired renal function, defined as a glomerular filtration rate of <90 mL/min/1.73 m(2). NT-proBNP levels were inversely correlated with glomerular filtration rate (Spearman's correlation coefficient = -0.457, P < 0.001). Overall, left ventricular dysfunction was diagnosed in 58 patients (48.3%). Median NT-proBNP levels were significantly higher in these patients, irrespective of whether their renal function was normal (3313 (interquartile range (IQR) 4603) vs 337 (IQR 695) pg/mL, P < 0.001) or impaired (5692 (IQR 10714) vs 887 (IQR 1165) pg/mL, P < 0.001). The areas under the receiver operating characteristic curves were 0.87 and 0.78, respectively. The threshold NT-proBNP value with the highest diagnostic accuracy was greater in the setting of renal dysfunction (2000 pg/mL; sensitivity 71%, specificity 82%, compared with 1000 pg/mL in patients with normal renal function; sensitivity 94%, specificity 82%). Multivariate analysis showed that left ventricular dysfunction and glomerular filtration rate were independently associated with elevated NT-proBNP levels. CONCLUSIONS: NT-proBNP remains an accurate biomarker for the diagnosis of left ventricular dysfunction associated with acute exacerbations of COPD. Threshold values of NT-proBNP were higher in patients with impaired renal function than in those with normal renal function.

Noninvasive ventilation and weaning in patients with chronic hypercapnic respiratory failure: a randomized multicenter trial.

RATIONALE: The use of noninvasive ventilation (NIV) as an early weaning/extubation technique from mechanical ventilation remains controversial. OBJECTIVES: To investigate NIV effectiveness as an early weaning/extubation technique in difficult-to-wean patients with chronic hypercapnic respiratory failure (CHRF). METHODS: In 13 intensive care units, 208 patients with CHRF intubated for acute respiratory failure (ARF) who failed a first spontaneous breathing trial were randomly assigned to three groups: conventional invasive weaning group (n = 69), extubation followed by standard oxygen therapy (n = 70), or NIV (n = 69). NIV was permitted as rescue therapy for both non-NIV groups if postextubation ARF occurred. Primary endpoint was reintubation within 7 days after extubation. Secondary endpoints were: occurrence of postextubation ARF or death within 7 days after extubation, use of rescue postextubation NIV, weaning time, and patient outcomes. MEASUREMENTS AND MAIN RESULTS: Reintubation rates were 30, 37, and 32% for invasive weaning, oxygen-therapy, and NIV groups, respectively (P = 0.654). Weaning failure rates, including postextubation ARF, were 54, 71, and 33%, respectively (P < 0.001). Rescue NIV success rates for invasive and oxygen-therapy groups were 45 and 58%, respectively (P = 0.386). By design, intubation duration was 1.5 days longer for the invasive group than in the two others. Apart from a longer weaning time in NIV than in invasive group (2.5 vs. 1.5 d; P = 0.033), no significant outcome difference was observed between groups. CONCLUSIONS: No difference was found in the reintubation rate between the three weaning strategies. NIV decreases the intubation duration and may improve the weaning results in difficult-to-wean patients with CHRF by reducing the risk of postextubation ARF. The benefit of rescue NIV in these patients deserves confirmation.

Meta-analysis of controlled studies on immunotherapy in severe scorpion envenomation.

BACKGROUND: Despite conflicting evidence, specific serotherapy is recommended for scorpion envenomation. METHODS: A meta-analysis of prospective or observational controlled studies, comparing intravenous scorpion antivenin (SAV) with control, was performed. Binary outcomes are reported as risk difference for clinical improvement and mortality rates. Analysis was performed both for the whole number of included studies and for two subgroups (set up according to the geographic origin of scorpions). RESULTS: Nine studies (four randomised controlled trials (RCTs), five observational) enrolling 687 patients were identified. Six dealt with Old World scorpions and three originated from Arizona. Overall, the rate of clinical improvement was similar in SAV treated and untreated patients (risk difference=0.22, 95% CI -0.35 to 0.79; p=0.45 for effect). Subgroup analysis showed favourable effects of SAV in the Arizona scorpion envenomation (risk difference=0.53; 95% CI 0.16 to 0.91; p<0.001), and non-significant unfavourable effects in Old World scorpion envenomation (risk difference=-0.05; 95% CI -0.28 to 0.18; p=0.65; p=0.003 for z-value, indicating a true heterogeneity of treatment effects). In Old World scorpion envenomation, there was no statistical difference in the risk of death in SAV treated and untreated scorpion envenomated patients (risk difference=0.007, 95% CI -0.02 to 0.03; p=0.6 for effect). Overall, administration of scorpion antivenin was associated with a reduction by 13 h in the mean time of symptom resolution (95% CI -17 to -9; p<0.0001). Serious adverse events were reported at a rate of 1-2% while minor adverse events occurred in up to 40% of patients. CONCLUSIONS: SAV should not be administered in Old World scorpion envenomation until its efficacy is established by an appropriately designed RCT. In the Arizona scorpion sting, SAV hastens the recovery process.

Standard versus newer antibacterial agents in the treatment of severe acute exacerbation of chronic obstructive pulmonary disease: a randomized trial of trimethoprim-sulfamethoxazole versus ciprofloxacin.

BACKGROUND. Although the use of antibiotics in the treatment of acute exacerbation of chronic obstructive pulmonary disease (COPD) is largely accepted, controversy remains regarding whether the choice of antibiotic has any impact on outcome. Our aim was to compare the effects of the combination of trimethoprim and sulfamethoxazole and ciprofloxacin in patients treated for severe COPD exacerbation requiring mechanical ventilation. METHODS. In a randomized, double-blind trial, we included 170 patients with an acute exacerbation of COPD requiring mechanical ventilation. Enrolled patients received trimethoprim-sulfamethoxazole (n = 85) or ciprofloxacin (n = 85) for 10 days. Main outcomes were hospital death and need for an additional course of antibiotics. Secondary outcomes were duration of mechanical ventilation, length of hospital stay, and exacerbation-free interval. RESULTS. Combined hospital death and additional antibiotic prescription rates were similar in the 2 groups (16.4% vs 15.3% for trimethoprim-sulfamethoxazole group vs ciprofloxacin group; difference, 1.1%; 95% confidence interval [CI] -9.8% to 12.0%; P = .832). Hospital death occurred in 7 patients (8.2%) receiving trimethoprim-sulfamethoxazole and 8 patients (9.4%) receiving ciprofloxacin (difference, -1.2%; 95% CI, -9.7 to 7.3; P = .90). The need for an additional antibiotic course was observed in 8 patients in the trimethoprim-sulfamethoxazole group and 5 patients in the ciprofloxacin group (difference, 2.3%; 95% CI, -5.4 to 10.0; P = .549). The mean exacerbation-free interval (+/- standard deviation) was similar in both treatment groups (83 +/- 25 vs 79 +/- 22 for the trimethoprim-sulfamethoxazole group vs ciprofloxacin group; difference, 4 days; 95% CI, -15 to 19 days; P = .41). Duration of mechanical ventilation and hospital stay was not significantly different between the 2 groups. CONCLUSIONS. In patients with acute exacerbation of COPD requiring mechanical ventilation, efficacy of trimethoprim-sulfamethoxazole was not inferior to ciprofloxacin. Trial registration. ClinicalTrials.gov identifier: NCT00791505.

The effect of prone positioning in acute respiratory distress syndrome or acute lung injury: a meta-analysis. Areas of uncertainty and recommendations for research.

OBJECTIVE: To compare the effects of ventilation in prone and in supine position in patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS). DESIGN: Meta-analysis of randomised controlled trials. DATA SOURCES: BioMedCentral, PubMed, CINAHL, and Embase (to November 2007), with additional information from authors. MEASUREMENTS AND RESULTS: From selected randomised controlled trials comparing positioning in ALI/ARDS we extracted data concerning study design, disease severity, clinical outcomes, and adverse events. Five trials including 1,372 patients met the inclusion criteria for mortality analysis; one trial was added to assess the effects on acquisition of ventilator-associated pneumonia (VAP). The included trials were significantly underpowered and enrolled patients with varying severity. Prone positioning duration and mechanical ventilation strategy were not standardised across studies. Using a fixed-effects model, we did not find a significant effect of prone positioning (proning) on mortality (odds ratio 0.97, 95% confidence interval 0.77-1.22). The PaO(2)/FiO(2) ratio increased significantly more with proning (weighted means difference 25 mmHg, p < 0.00001). Proning was associated with a non-significant 23% reduction in the odds of VAP (p=0.09), and with no increase in major adverse airway complications: OR 1.01, 95% CI 0.71-1.43. Length of intensive care unit stay was marginally and not significantly increased by proning. CONCLUSIONS: Prone position is not associated with a significant reduction in mortality from ALI/ARDS despite a significant increase in PaO(2)/FiO(2), is safe, and tends to decrease VAP. Published studies exhibit substantial clinical heterogeneity, suggesting that an adequately sized study optimising the duration of proning and ventilation strategy is warranted to enable definitive conclusions to be drawn.

A clinical score predicting the need for hospitalization in scorpion envenomation.

OBJECTIVE: Predicting complications is a clinical challenge in the assessment of victims of scorpion envenomation (SE). We sought to develop a clinical score to predict need for hospitalization after scorpion sting. METHODS: We prospectively collected data in patients attending the emergency department after SE in derivation (n = 868) and validation groups (n = 435). A score was derived from a multiple regression analyses using clinical variables as dependent variables and hospitalization as independent variable. RESULTS: Discrimination power of the constructed score was good (area under the receiver operating characteristic curve, 0.85 and 0.83 in derivation and validation group, respectively). Goodness-of-fit tests indicated that the score performed well in the derivation and the validation groups (P = .88 and P = .67 respectively). The score has a good sensitivity and negative predictive value at cutoff value of 2. CONCLUSION: Our clinical score could be used for efficient hospital admission decision in patient's victims of SE.

Effects of norepinephrine on static and dynamic preload indicators in experimental hemorrhagic shock.

OBJECTIVE: To investigate the effect of norepinephrine on static (right atrial pressure, pulmonary artery occlusion pressure ) and dynamic (pulse pressure variation and arterial systolic pressure variation) preload indicators in experimental hemorrhagic shock. DESIGN: Prospective controlled experimental study. SETTING: Animal research laboratory. SUBJECTS: Six anesthetized and mechanically ventilated dogs. INTERVENTIONS: Dogs were instrumented for measurement of arterial blood pressure, pulmonary artery catheter derived variables including right atrial pressure, pulmonary artery occlusion pressure, and cardiac output. Simultaneously, pulse pressure variation and systolic pressure variation were calculated. Pulse pressure variation is the difference between the maximal and the minimal value of pulse pressure divided by the mean of the two values and is expressed as a percentage. Systolic pressure variation is the difference between the maximal and the minimal systolic pressure and is expressed as an absolute value. After baseline measurements, hemorrhagic shock was induced by a stepwise cumulative blood withdrawal of 35 mL.kg of body weight. A second set of hemodynamic measurement was made 30 mins after bleeding. The third set was made 30 mins later under norepinephrine. MEASUREMENTS AND MAIN RESULTS: Mean arterial pressure and cardiac output decreased after hemorrhage (p < .05), whereas right atrial pressure and pulmonary artery occlusion pressure remained unchanged. Baseline pulse pressure variation and systolic pressure variation increased significantly with hemorrhage, from 12% (9%) to 28% (11.5%) (p < .001) and from 12.5 (6.5) to 21 (8.2) mm Hg (p < .05), respectively. Norepinephrine induced a significant increase of cardiac output and a significant decrease of pulse pressure variation and systolic pressure variation but did not significantly change right atrial pressure or pulmonary artery occlusion pressure values. Stroke volume was correlated to pulse pressure variation and systolic pressure variation but was not correlated to right atrial pressure or pulmonary artery occlusion pressure. CONCLUSION: Our study confirms the superiority of dynamic variables (pulse pressure variation and systolic pressure variation) over static ones (right atrial pressure and pulmonary artery occlusion pressure) in assessing cardiac preload changes in hemorrhagic shock. However, norepinephrine could significantly reduce the value of these dynamic variables and mask a true intravascular volume deficit possibly by shifting blood from unstressed to stressed volume.

Neurohormonal activation in severe scorpion envenomation: correlation with hemodynamics and circulating toxin.

We studied the effects of scorpion (Androctonus australis hector) venom on hemodynamics and on the release of catecholamines, neuropeptide Y (NPY), endothelin-1 (ET-1) and atrial natriuretic peptide (ANP) in dog model of severe scorpion envenomation. Nine mongrel anesthetized dogs were submitted to mechanical ventilation through intubation and were administered intravenously purified dried scorpion venom (Androctonus autstralis) 0.05 mg/kg. Measurements including pulmonary artery catheter derived parameters, serum toxin levels and humoral variables were performed at baseline (before venom injection) and 5, 15, 30 and 60 min after venom injection. Humoral variables included: serum lactate, epinephrine (EP), norepinephrine (NE), NPY, ET-1 and ANP plasma concentrations. Scorpion venom caused rapid and transient increase of mean arterial pressure (MAP) and PAOP associated with a marked and sustained decline in cardiac output (-55% at 60 min; P < 0.001). Hemodynamic changes were associated with a rapid and significant increase of all measured hormones. The highest increase was for NE (28-fold) and EP (25-fold). MAP was closely correlated with NE and less significantly correlated with toxin levels. Similarly, significant correlation was observed between PAPO and ANP plasma levels. These findings support the implication of excessive catecholamines release in hemodynamic disturbances of severe SE and suggest that NPY and ET-1 could be involved in this process. Serum toxin does not appear to consistently contribute to these effects. Through its correlation with PAOP, ANP could be a reliable and useful marker of cardiac dysfunction in SE.

Diagnosis of ventilator-associated pneumonia: agreement between quantitative cultures of endotracheal aspiration and plugged telescoping catheter.

OBJECTIVE: To evaluate the diagnostic agreement between quantitative cultures of samples obtained with endotracheal aspiration (ETA) and plugged telescoping catheter (PTC). DESIGN: Prospective study. SETTING: Medical ICU. PATIENTS: Hundred thirty-eight episodes of suspected ventilator-associated pneumonia studied in 100 consecutive patients. INTERVENTIONS: For each suspected episode of ventilator-associated pneumonia, ETA and PTC were performed consecutively. The agreement between microbiological results obtained from the two techniques was evaluated (kappa statistic test). Pneumonia was diagnosed on a positive culture result of telescoping catheter with the threshold set at 10(3) cfu/ml or more. The cut-off points evaluated for ETA ranged from 10(2 )to 10(6) cfu/ml. RESULTS: Micro-organisms retrieved by aspiration and telescoping catheter were similar and bacterial counts obtained by the two procedures were well correlated ( r = 0.71 p < 0.001). There was good agreement between positive and negative ETA and PTC specimens (kappa: 0.78) with a diagnostic threshold for ETA of 10(4) cfu/ml. The sensitivity and specificity of ETA for the diagnosis of PTC-confirmed pneumonia were 92% and 85%, respectively. Kappa decreased to 0.48 when the diagnostic threshold was increased to 10(6) cfu/ml. CONCLUSIONS: Quantitative cultures of ETA and PTC tallied for both micro-organisms and counts. The simpler ETA appears adequate for determining the presence of pathogenic organisms in significant concentration in the lower respiratory tract.