Scorpion envenomation: state of the art Abroug, Fekri; Ouanes-Besbes, Lamia; Tilouche, Nejla ...
Intensive care medicine,
03/2020, Letnik:
46, Številka:
3
Journal Article
Recenzirano
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.
Exacerbations are part of the natural history of chronic obstructive pulmonary disease and asthma. Severe exacerbations can cause acute respiratory failure, which may ultimately require mechanical ...ventilation. This review summarizes practical ventilator strategies for the management of patients with obstructive airway disease. Such strategies include non-invasive mechanical ventilation to prevent intubation, invasive mechanical ventilation, from the time of intubation to weaning, and strategies intended to prevent post-extubation acute respiratory failure. The role of tracheostomy, the long-term prognosis, and potential future adjunctive strategies are also discussed. Finally, the physiological background that underlies these strategies is detailed.
Abstract
Context. Scorpion envenomation is a threat to more than 2 billion people worldwide with an annual sting number exceeding one million. Acute heart failure presenting as cardiogenic shock or ...pulmonary edema, or both is the most severe presentation of scorpion envenomation accounting for 0.27% lethality rate. Objective. The purpose of this review is to characterize the scorpion-related cardiomyopathy, clarify its pathophysiological mechanisms, and describe potentially useful treatments in this particular context. Methods. We searched major databases on observational or interventional studies (whether clinical or experimental) on the cardiorespiratory consequences of scorpion envenomation and their treatment. No limit of age or language was imposed. A critical appraisal of the literature was conducted in order to provide a pathophysiological scheme that reconciles reported patterns of cardiovascular toxicity and hypotheses and assumptions made so far. Results. Early cardiovascular dysfunction is related to the so-called "vascular phase" of scorpion envenomation, which is related to a profound catecholamine-related vasoconstriction leading to a sharp increase in left ventricular (LV) afterload, thereby impeding LV emptying, and increasing LV filling pressure. Following this vascular phase, a myocardial phase occurs, characterized by a striking alteration in LV contractility (myocardial stunning), low cardiac output, and hypotensive state. The right ventricle involvement is symmetric to that of LV with a profound and reversible alteration in right ventricular performance. This phase is unique in that it is reversible spontaneously or under inotropic treatment. Scorpion myocardiopathy combines the features of takotsubo myocardiopathy (or stress myocardiopathy) which is linked to a massive release in catecholamines leading to myocardial ischemia through coronary vasomotor abnormalities (epicardial coronary spasm and/or increase in coronary microvascular resistance). Treatment of pulmonary edema due to scorpion envenomation follows the same principles as those applied for the treatment of cardiogenic pulmonary edema in general: this begins with oxygen supplementation targeting an oxygen saturation of 92% or more, by oxygen mask, continuous positive airway pressure, noninvasive ventilation, or conventional mechanical ventilation. Dobutamine effectively improves hemodynamic parameters and may reduce mortality in severe scorpion envenomation. Conclusion. Scorpion cardiomyopathy is characterized by a marked and reversible alteration in biventricular performance. Supportive treatment relying on ventilatory support and dobutamine infusion is a bridge toward recovery in the majority of patients.
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.
In 2013 in Tunisia, 3 persons in 1 family were infected with Middle East respiratory syndrome coronavirus (MERS-CoV). The index case-patient's respiratory tract samples were negative for MERS-CoV by ...reverse transcription PCR, but diagnosis was retrospectively confirmed by PCR of serum. Sequences clustered with those from Saudi Arabia and United Arab Emirates.
Purpose
To evaluate and compare the performance of NT-proBNP levels, plasma protein concentration, hematocrit, and fluid balance for the preceding 24 h in predicting the outcome of the two steps of ...weaning: (1) spontaneous breathing trial (SBT), (2) extubation.
Methods
This was a prospective observational study of 143 patients who were mechanically ventilated for more than 48 h (55 % COPD) and were ready to wean. They underwent an SBT and were extubated when they passed the trial. Immediately before the SBT, we measured the evaluated diagnosis tools.
Results
Of 143 patients, 80 (56 %) passed the SBT and were extubated. Of these, two were reintubated for laryngeal dyspnea, 57 had no respiratory problem during the next 48 h, and 21 developed post-extubation respiratory distress (26 %). Rescue noninvasive ventilation (NIV) prevented reintubation in 15 (71 %). None of the tested diagnosis tools predicted the outcome of the SBT. Patients who developed post-extubation respiratory distress were older, had lower values of plasma protein concentration and higher values of NT-proBNP than those who did not. Only NT-proBNP was an independent predictor of the occurrence of post-extubation respiratory distress (OR 1.2; 95 % CI 1.09–1.4;
p
= 0.003); the area under the ROC curve for NT-proBNP to predict post-extubation respiratory distress was 0.78 (95 % CI 0.67–0.89;
p
= 0.0001). NT-proBNP was more accurate to rule out (negative likelihood ratio 0.09 for a cutoff of no greater than 1,000 pg/ml) than to rule in the risk of post-extubation respiratory distress (positive likelihood ratio 3.45 for a cutoff of at least 2,000 pg/ml).
Conclusion
NT-proBNP levels at SBT help in the prediction of post-extubation respiratory distress and could identify the subgroup of extubated patients requiring close observation and/or prophylactic NIV.
ABSTRACT
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 m2. 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.
NT‐proBNP levels were effective for the diagnosis of left ventricular dysfunction in patients with acute exacerbations of COPD. The diagnostic accuracy of NT‐proBNP levels in the setting of impaired renal function was confirmed. Diagnosis thresholds were higher in patients with impaired renal function compared to those without.
When used as a driving gas during NIV in hypercapnic COPD exacerbation, a helium–oxygen (He/O
2
) mixture reduces the work of breathing and gas trapping. The potential for He/O
2
to reduce the rate ...of NIV failure leading to intubation and invasive mechanical ventilation has been evaluated in several RCTs. The goal of this meta-analysis is to assess the effect of NIV driven by He/O
2
compared to air/O
2
on patient-centered outcomes in hypercapnic COPD exacerbation. Relevant RCTs were searched using standard procedures. The main endpoint was the rate of NIV failure. The effect size was computed by a fixed-effect model, and estimated as odds ratio (OR) with 95% confidence interval (CI). Additional endpoints were ICU mortality, NIV-related side effects, and the length and costs of ICU stay. Three RCTs fulfilled the selection criteria and enrolled a total of 772 patients (386 patients received He/O
2
and 386 received air/O
2
). Pooled analysis showed no difference in the rate of NIV failure when using He/O
2
mixture compared to air/O
2
: 17 vs 19.7%, respectively; OR 0.84, 95% CI 0.58–1.22; p = 0.36;
I
2
for heterogeneity = 0%, and no publication bias. ICU mortality was also not different: OR 0.8, 95% CI 0.45–1.4; p = 0.43;
I
2
= 5%. However, He/O
2
was associated with less NIV-related adverse events (OR 0.56, 95% CI 0.4–0.8, p = 0.001), and a shorter length of ICU stay (difference in means = −1.07 day, 95% CI −2.14 to −0.004, p = 0.049). Total hospital costs entailed by hospital stay and NIV gas were not different: difference in means = −279$, 95% CI −2052–1493, p = 0.76. Compared to air/O
2
, He/O
2
does not reduce the rate of NIV failure in hypercapnic COPD exacerbation. It is, however, associated with a lower incidence of NIV-related adverse events and a shortening of ICU length of stay with no increase in hospital costs.
Unrecognized chronic heart failure is present in 21-30% of chronic obstructive pulmonary disease patients. It may be a precipitating factor for acute exacerbation of chronic obstructive pulmonary ...disease or may hinder weaning from mechanical ventilation. The aim of the review is to emphasize recent studies that validated measurements of plasma B-type natriuretic peptide in the diagnosis of heart dysfunction in chronic obstructive pulmonary disease patients.
Measurements of B-type natriuretic peptide or N-terminal pro-B-type natriuretic peptides are accurate in the diagnosis of left heart dysfunction in chronic obstructive pulmonary disease patients either in stable condition or during acute exacerbation of chronic obstructive pulmonary disease. Natriuretic peptide thresholds are elevated in comparison to cut-offs usually reported in patients without pulmonary disease. B-type natriuretic peptide dosage is also able to uncover new onset of left heart failure associated with weaning difficulties from mechanical ventilation in chronic obstructive pulmonary disease patients.
Recent evidence suggests that natriuretic peptide measurements are accurate in the diagnosis of coexisting left heart failure in chronic obstructive pulmonary disease patients, either in stable condition or during severe cardiopulmonary interactions occurring during acute exacerbation of chronic obstructive pulmonary disease, or evoking weaning difficulties related to left heart dysfunction.
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