Factors influencing preoperative stress response in coronary artery bypass graft patients

BACKGROUND: In many studies investigating measures to attenuate the hemodynamic and humoral stress response during induction of anaesthesia, primary attention was paid to the period of endotracheal intubation since it has been shown that even short-lasting sympathetic cardiovascular stimulation may have detrimental effects on patients with coronary artery disease. The aim of this analysis was, however, to identify the influencing factors on high catecholamine levels before induction of anaesthesia. METHODS: Various potential risk factors that could impact the humoral stress response before induction of anaesthesia were recorded in 84 males undergoing coronary aortic bypass surgery, and were entered into a stepwise linear regression analysis. The plasma level of norepinephrine measured immediately after radial artery canulation was chosen as a surrogate marker for the humoral stress response, and it was used as the dependent variable in the regression model. Accordingly, the mean arterial blood pressure, heart rate and the calculated pressure-rate product were taken as parameters of the hemodynamic situation. RESULTS: Stepwise regression analysis revealed that the oral administration of low-dose clonidine (mean dose 1.75 μg·kg(-1)) on the morning of surgery was the only significant predictor (p = 0.004) of the high variation in preoperative norepinephrine plasma levels. This intervention decreased norepinephrine levels by more than 40% compared to no clonidine administration, from 1.26 to 0.75 nmol·l(-1). There was no evidence for dose-responsiveness of clonidine. All other potential predictors were removed from the model as insignificant (p > 0.05). The use of beta-blocker, ace-inhibitors, ejection fraction, and body mass index were significant determinants for the hemodynamic situation (heart rate, mean arterial pressure, pressure rate product) of the patient during the pre-induction period. CONCLUSION: The oral administration of clonidine is the only significant predictor for the observed variation of norepinephrine levels during the preoperative period. Lack of significant dose responsiveness suggests that even a low dose of the drug can attenuate the preoperative stress response and thus is recommended in cardiovascular high risk patients

Initial 24-Hour ICU Glucose Levels are Associated with the Development of Cerebral Vasospasm after Subarachnoid Haemorrhage

Cerebral vasospasm (CVS) is a well-known cause of morbidity and mortality amongst patients who have suffered from subarachnoid haemorrhage (SAH). Its presence is associated with reduced cerebral perfusion and potential further development of neurological deficit. The aetiology of CVS has been proven to be multifactorial and several risk factors have been associated with its development. Since CVS has been linked to signalling changes in vascular endothelium, serum glucose was chosen as a potential prognostic indicator and risk factor due to its relation with endothelial dysfunction. The objective of this study was to evaluate the association between serum glucose levels in ICU patients admitted with SAH and the development of CVS. The study is a retrospective observational study in which data was collected on patients admitted to the ICU of Pauls Stradiņš Clinical University Hospital with the primary diagnosis of SAH. We compared serum glucose levels on ICU admission and average glucose levels for the first 5 days in the ICU in patients with and without subsequent development of CVS. Twenty-four patients diagnosed with SAH were included in the study. CVS was confirmed in 25% (n=6). There was no significant difference in age and gender distribution between groups. Patients with subsequent development of CVS had higher WFNS score values (4.80 and 3.56; p=0.008). We found lower mean glucose levels on admission for patients that developed CVS compared to those that did not develop CVS (7.32 and 9.28 mmol/L; p=0.05). The average glucose levels on first 24h of ICU stay were also lower in patients who developed CVS (7.26 and 9.29 mmol/L; p=0.03). There were no significant differences in average glucose levels between groups from day 2 to day 5 of ICU stay. Overall mortality was not affected by ICU glucose levels and average glucose levels of first 24h were negatively correlated to the duration of ICU stay (rs = -0.408, p<0.05). The study shows that admission and initial average 24h glucose levels may prove to be a prognostic indicator for the potential development of CVS after SAH. Glucose averages of the first day of ICU stay were significantly related to the development of CVS and may demonstrate importance after further investigation, possibly with a larger patient group

Cyanide poisoning by fire smoke inhalation: A European expert consensus

Smoke inhalation is a common cause of cyanide poisoning during fires, resulting in injury and even death. In many cases of smoke inhalation, cyanide has increasingly been recognized as a significant toxicant. The diagnosis of cyanide poisoning remains very difficult, and failure to recognize it may result in inadequate or inappropriate treatment. Findings suggesting cyanide toxicity include the following: (a) a history of enclosed-space fire; (b) any alteration in the level of consciousness; (c) any cardiovascular changes (particularly inexplicable hypotension); and (d) elevated plasma lactate. The feasibility and safety of empiric treatment with hydroxocobalamin for fire smoke victims have been reported in the literature. On the basis of a literature review and a panel discussion, a group of European experts has proposed emergency management protocols for cyanide toxicity in fire smoke victims. © 2013 Wolters Kluwer Health | Lippincott Williams &amp; Wilkins

Antidotes for cyanide poisoning---author's reply

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A non-interventional comparative study of the 20:1 combination of cafedrine/theodrenaline versus ephedrine for the treatment of intra-operative arterial hypotension: the ‘HYPOTENS’ study design and rationale

<p><b>Objective:</b> To compare the effectiveness of 20:1 cafedrine/theodrenaline approved for use in Germany to ephedrine in the restoration of arterial blood pressure and on post-operative outcomes in patients with intra-operative arterial hypotension of any origin under standard clinical practice conditions.</p> <p><b>Methods and results:</b> ‘HYPOTENS’ is a national, multi-center, prospective, open-label, two-armed, non-interventional study. Effectiveness and post-operative outcome following cafedrine/theodrenaline or ephedrine therapy will be evaluated in two cohorts of hypotensive patients. Cohort A includes patients aged ≥50 years with ASA-classification 2–4 undergoing non-emergency surgical procedures under general anesthesia. Cohort B comprises patients undergoing Cesarean section under spinal anesthesia. Participating surgical departments will be assigned to a treatment arm by routinely used anti-hypotensive agent. To minimize bias, matched department pairs will be compared in a stratified selection process. The composite primary end-point is the lower absolute deviation from individually determined target blood pressure (IDTBP) and the incidence of heart rate ≥100 beats/min in the first 15 min. Secondary end-points include incidence and degree of early post-operative delirium (cohort A), severity of fetal acidosis in the newborn (cohort B), upper absolute deviation from IDTBP, percentage increase in systolic blood pressure, and time to IDTBP.</p> <p><b>Conclusion:</b> This open-label, non-interventional study design mirrors daily practice in the treatment of patients with intra-operative hypotension and ensures full treatment decision autonomy with respect to each patient’s individual condition. Selection of participating sites by a randomization process addresses bias without interfering with the non-interventional nature of the study. First results are expected in 2018. ClinicalTrials.gov identifier: NCT02893241; DRKS identifier: DRKS00010740.</p