Midazolam and dexmedetomidine sedation impair systolic heart function

BACKGROUND

Sedation is an essential part of clinical practice. Despite this fact, we still lack data describing the exact impact of sedation on heart function.

PURPOSE

To compare the changes in heart function, induced after sedation with either midazolam or dexmedetomidine, using cardiac magnetic resonance imaging (MRI).

METHODS

A total number of 30 volunteers were randomized into two groups: 15 participants in the midazolam group (MID) and 15 participants in the dexmedetomidine group (DEX). Every participant underwent a one-session cardiac MRI before and after sedation onset. The following parameters were recorded: left and right ventricle stroke volume (Ao-vol and Pul-vol resp.) and maximum flow velocity through the mitral valve during early (E-diast) and late diastole (L-diast). A monitor recorded values of mean blood pressure (MAP), pulse (P) and blood oxygen saturation (SpO2) in 5-minute intervals.

RESULTS

Dexmedetomidine led to a statistically significant decrease in Ao-vol (p = 0.006) and Pul-vol (p = 0.003), while midazolam decreased E-diast (p = 0.019) Ao-vol (p = 0.001) and Pul-vol (p = 0.01). The late diastolic filling was not influenced by the sedation technique.

CONCLUSION

Both sedation regimens worsened the systolic function of both ventricles. Midazolam moreover attenuated early diastolic filling of the left ventricle (Tab. 3, Fig. 4, Ref. 19).

Novel patterns of left ventricular mechanical activity during experimental cardiac arrest in pigs

We conducted an experimental study to evaluate the presence of coordinated left ventricular mechanical myocardial activity (LVMA) in two types of experimentally induced cardiac arrest: ventricular fibrillation (VF) and pulseless electrical activity (PEA). Twenty anesthetized domestic pigs were randomized 1:1 either to induction of VF or PEA. They were left in nonresuscitated cardiac arrest until the cessation of LVMA and microcirculation. Surface ECG, presence of LVMA by transthoracic echocardiography and sublingual microcirculation were recorded. One minute after induction of cardiac arrest, LVMA was identified in all experimental animals. In the PEA group, rate of LVMA was of 106+/-12/min. In the VF group, we identified two patterns of LVMA. Six animals exhibited contractions of high frequency (VFhigh group), four of low frequency (VFlow group) (334+/-12 vs. 125+/-32/min, p<0.001). A time from cardiac arrest induction to asystole (19.2+/-7.2 vs. 7.3+/-2.2 vs. 8.3+/-5.5 min, p=0.003), cessation of LVMA (11.3+/-5.6 vs. 4.4+/-0.4 vs. 7.4+/-2.9 min, p=0.027) and cessation of microcirculation (25.3+/-12.6 vs. 13.4+/-2.4 vs. 23.2+/-8.7 min, p=0.050) was significantly longer in VFlow group than in VFhigh and PEA group, respectively. Thus, LVMA is present in both VF and PEA type of induced cardiac arrest and moreover, VF may exhibit various patterns of LVMA.

The practice of therapeutic mild hypothermia in cardiac arrest survivors in the Czech republic

BACKGROUND

The proper performance of therapeutic mild hypothermia (TH) in cardiac arrest survivors is a prerequisite for achieving the best possible outcome. We analyzed the recent technical issues of in-hospital TH practices in the Czech Republic.

METHODS

As the second project of the PRE-COOL (Pre-hospital Cooling in Cardiac Arrest Patients) working group, we compiled the directory of all non-surgical intensive care units (ICUs) in the Czech republic. A head physician of every ICU was provided a structured questionnaire in October 2008.

RESULTS

From a total of 487 ICUs that were sent the questionnaire, 41.5% responded. We analyzed the responders that provide early post-resuscitation care, including TH (N=90). The site of TH initiation was most frequently an ICU bed (93.3%). A broad TH indication irrespective of the initial rhythm, cardiac arrest location or the presence of witnesses was reported by 48.9% of the responders. Up to 81.1% of the responding ICUs did not exclude from TH therapy patients who were developing post-resuscitation shock. Complex neuroprotective and cardioprotective approaches (TH, urgent coronary intervention, control of glycemia and early goal-directed hemodynamic support) were practiced at 52.2% of the ICUs. Of the responders, 54.4% cooled patients for 24 hours. The most frequently used cooling techniques were surface cooling with ice packs (88.9%) and intravenous cold infusion (84.4%).

CONCLUSION

The survey revealed the recent practice of TH management of cardiac arrest survivors in the Czech republic. The modes of TH practice were different in many aspects, and unifying the basic components is advisable.

[Current cooling methods for induction of mild hypothermia in cardiac arrest survivors]

Induction of mild therapeutic hypothermia early after return of spontaneous circulation improves prognosis of cardiac arrest survivors. Rapid cooling of the patients and correct maintainance of the target therapeutic temperature followed by controlled slow rewarming can be achieved by several noninvasive and invasive methods of various efficacy. Elementary and the most frequently used methods are surface cooling via ice-packs and rapid intravenous administration of cold crystaloids. Mattress cooling systems and facilities for endovascular cathether-cooling are more sophisticated, manageable and ensure more precise titration of therapeutic temperature. Cooling caps and helmets leading to selective head cooling can be used as the complementary techniques. Several other methods are too instrumentation-intensive, too invasive or investigated in animal experiments only. Anyway, near future may bring a rapid development of new effective and safe cooling systems.

Intravascular ultrasound assessment of coronary artery involvement in Fabry disease

AIM

We used intravascular ultrasound (IVUS) to characterize coronary artery involvement in patients with Fabry disease (FD).

METHODS

Nine FD patients (5 women) were matched to 10 control patients (5 women) chosen from our IVUS database. Standard volumetric IVUS analyses were performed along with assessment of plaque echodensity.

RESULTS

Plaques in FD patients were diffuse and hypoechogenic compared with more focal and more echogenic lesions in control patients. Echogenicity of plaques was significantly lower in FD patients (median 30.7 +/- 12.9 vs 55.9 +/- 15.7, p = 0.0052, mean 37.2 +/- 15.6 vs 66.2 +/- 13.3, p = 0.0014). Diffusiveness was assessed as differences between mean and median plaque burden versus the plaque burden in each of the analysed cross-sections. These differences were lower in FD vs controls (5.8 +/- 4.8 vs 8.7 +/- 6.6, p < 0.001 for mean, and 5.8 +/- 4.9 vs 8.8 +/- 7.3, p < 0.001 for median) indicating a more diffuse involvement. The occurrence of lipid cores was significantly higher in FD patients than in controls (2.4 +/- 1.5 vs 1.0 +/- 0.94, p = 0.02).

CONCLUSION

IVUS showed diffuse hypoechogenic plaques in patients with FD. The explanation may be higher lipid content in plaques and accumulation of glycosphingolipid in smooth-muscle and endothelial cells.

[Overcooling during mild hypothermia in cardiac arrest survivors--phenomenon we should keep in mind]

BACKGROUND

Mild hypothermia (MH) in cardiac arrest survivors has became a routine part of early postresuscitative support. Overcooling is a frequent phenomenon with the unknown outcome.

AIM OF THE STUDY

To analyze the incidence and outcome ofovercooling below body core temperature (BT) of 32 degrees C.

MATERIAL AND METHODS

We performed retrospective analysis of all 56 consecutive cardiac arrest survivors treated by MH who reached therapeutic BT in the 2nd Department of Internal Medicine, General Teaching Hospital, Prague. MH was initiated as soon as possible after the return of spontaneous circulation to reach BT of 33 degrees C followed by maintainance of BT 32-34 degrees C for 12 hours. Patients were cooled by surface cooling via ice-packs and by interavenous infusion of cold crystaloids.

RESULTS

Overcooling below BT of 32 degrees C was observed in 23 patients (41%). This group of patients had more frequently asystole as the initial rhythm (34.8 vs 9.1%), more frequently were cooled by combinatory cooling approach (56.5 vs 27.3%), more frequently had lower baseline BT (35.3 +/- 1.3 vs 36.2 +/- 1.2 degrees C), higher cooling rate (the interval required for a decrease of BT by 1 degrees C 61.5 +/- 53.1 vs 90.1 +/- 50.0 min) (all p < 0.05) than patients with proper profile of BT during MH. Overcooling was independent negative predictor of discharge favourable neurological outcome (OR 0.16, 0.022-0.77, p = 0.037).

CONCLUSION

Induction of MH by conventional cooling approach is burdened by high risk of overcooling. This phenomenon is probably associated with worse outcome.

Induction of mild hypothermia in cardiac arrest survivors presenting with cardiogenic shock syndrome

BACKGROUND

Induction of mild hypothermia (MH) in patients resuscitated from cardiac arrest improves their outcome. However, benefits and risks of MH in patients who remain in cardiogenic shock after the return of spontaneous circulation (ROSC) are unclear. We analysed all cardiac arrest survivors who were treated with MH in our intensive coronary care unit (CCU) and compared the outcome of patients with cardiogenic shock syndrome (CSS) with those who were circulatory stable.

METHODS

We performed retrospective analysis of all consecutive cardiac arrest survivors treated by MH in our CCU from November 2002 to August 2006. They were classified into two groups, according to whether they met the criteria for cardiogenic shock or not before MH initiation.

RESULTS

Out of 56 consecutive patients, 28 fulfilled criteria of cardiogenic shock before MH initiation (group A) and 28 were relatively stable (group B). In-hospital mortality was 57.1% in group A and 21.4% in group B patients (P=0.013). Favourable neurological outcome anytime during hospitalization was found in 67.9% of group A patients and in 82.1% of group B subjects (P=0.355). Favourable discharge neurological outcome was reached in 39.3% in group A and in 71.4% in group B (P=0.031). The complication rate in both groups did not differ.

CONCLUSION

While in-hospital mortality in cardiac arrest survivors treated by MH was expectably higher in those with cardiogenic shock than in stable patients, the favourable neurological outcome during hospitalization was comparable in both groups. Therefore, induction of MH should be considered in cardiac arrest survivors with CSS after ROSC.

[Current approach to the diagnostics and therapy of acute coronary syndromes]

The aim of this review is to provide a comprehensive actual overview of the current approach to acute coronary syndromes diagnostics, therapeutics and secondary prevention. Authors stress early diagnosis, risk stratification, indication and timing of interventional therapy. It is not an intention to provide detailed description of all clinical studies implemented recently in the field of acute coronary syndromes.

[Long-term treatment with statins in patients with ischemic heart disease after coronary angioplasty]

Long-term statin therapy is the corner-stone in management of patients with coronary artery disease.

PURPOSE OF STUDY

The aim of our study was to analyze the state of the statin therapy at patients undergoing percutaneous coronary intervention (PCI) and to determine predictors of long-term statin treatment.

METHODS

We performed a retrospective study in 520 patients who underwent percutaneous coronary angioplasty in 2nd Dept. of Internal Medicine, 1st School of Medicine, Charles University, Prague during the year 2000. Data were collected from hospital records and from a mailed questionnaire.

RESULTS

The response rate was 61.9% and the average response time was 11.6 +/- 3.5 months after PCI. Long-term statin therapy was prescribed in 52.5%. In patients with hypercholesterolemia 67.1% were treated in comparison with 32.3% treated patients without this diagnosis (p < 0.0001). Patients aged 70 years and older were treated significantly less frequently then younger individuals (30.6% vs. 61.3%, p < 0.0001). Patients with a history of prior revascularization procedure were treated significantly more often then patients undergoing the first procedure (64.8% vs. 49.8%, p < 0.05). Multivariate logistic regression analysis was applied to detect significant predictors of long-term statin therapy. Only hypercholesterolemia and statin prescription at discharge were identified as independent positive predictors, whereas age > or = 70 years and male gender had negative predictive value.

CONCLUSION

By course of evidence-based medicine, patients who underwent PCI in our study are undertreated by statins. Statin treatment should be initiated in all patients treated by PCI with increased cardiovascular risk. Patients at defined risk for undertreatment are mainly older patients and men. The prescription of statin therapy at the time of hospital discharge appears to be a very effective tool to improve long-term statin therapy.

[Contrast nephropathy and its prevention]

Contrast-induced nephropathy is one of the adverse events of diagnostic and therapeutic intravascular application of contrast agent. In general, the condition was defined as an increase in the serum creatinine concentration of more than 44 mmol/l or of more than 25% within 48 hours after the contrast agent administration. Other cause of creatinine increase should be excluded. Contrast-induced nephropathy has been reported to be the third leading cause of acute nephropathy in hospitalized patients, occurring at a rate of 1-6% in unselected population and of 30-50% in high-risk patients. One year mortality can be as high as 45% in high-risk patient population. The most important risk factors are chronic renal insufficiency, diabetes mellitus and high volume of contrast agent. Clinical presentation is mostly asymptomatic, but in some patients acute renal failure with necessity of hemodialysis can occur. Prevention is underlying tool in reducing of contrast-induced nephropathy incidence. It is based on the identification of risk patients, stop of medication which can increase risk of contrast-induced nephropathy and proper hydratation of patients before, during and after the contrast agent administration. In high-risk patients, non-ionic and low-osmolarity contrast agent should be used. Several clinical studies testing different drugs to prevent contrast-induced nephropathy were performed, but no convincing result has been found. Promising substancies are N-acetylcysteine and fenoldopam.

[Cardiogenic shock--a complex therapeutic approach]

Cardiogenic shock belongs to the most severe and immediately life-threatening complications of the acute myocardial infarction. Despite development of modern diagnostic and therapeutic methods the incidence and mortality of cardiogenic shock has not significantly declined in the past decades. Early reperfusion strategy with percutaneous revascularization has become a cornerstone of therapy. The complex approach to cardiogenic shock comprises pharmacological and mechanical hemodynamic support, ventilatory support utilizing new ventilator regimens, metabolic and renal support/replacement with continuous renal replacement therapies and psychological, eventually psychopharmacological support. All these measures enable prevention of the multiple organ failure syndrome development and positively influence high mortality of patients suffering from cardiogenic shock.

[Direct percutaneous transluminal coronary angioplasty in patients with acute myocardial infarct treated at the Cardiac Center of the General Medical School Hospital in Prague: a 1-year retrospective study]

Direct percutaneous transluminal coronary angioplasty (d-PTCA) in patients with acute myocardial infarctions (AIM) has become an alternative of thrombolytic treatment. If the involved department has adequate experience the success rate of the procedure is high and the immediate and long-term results are better than those of thrombolysis. Moreover contrary to thrombolytic treatment successful percutaneous coronary intervention in AIM is more beneficial for patients also later than 6 hours after the development of infarction pain. In the Cardiocentre of the General Faculty Hospital (GFH) patients with AIM are constantly attended, i.e. those indicated for reperfusion therapy are treated solely by the d-PTCA method.

OBJECTIVE AND METHOD

Retrospective analysis of d-PTCA in AIM made during the annual period from Jan. 1 2000 to Dec. 31 2000. Into the observation study patients were included with clinical and/or ECG signs of AIM when the period from the onset of pain to the beginning of intervention did not exceed 12 hours. All patients were given before the procedures 500 mg of acetylsalicylic acid and 10,000 u. heparin. Cardiac catheterization was implemented by the percutaneous Seldinger technique via the a. femoralis l.dx., in exceptional cases from the left femoral artery. An approach via the a. radialis and/or a. brachialis was not used in any of the patients. From the investigation patients were excluded who had before the percutaneous coronary intervention (PCI) a thrombolytic preparation (so-called rescue-PTCA).

RESULTS

During the mentioned period in the Cardiocentre of the GFH a total of 673 PTCA were performed, incl. 127 (18.9%) d-PTCA in patients with AIM. In the mentioned group of 127 patients subjected to intervention were 87 (68.5%) men and 40 (31.5%) women. The mean age of the men was 59.1 +/- 12 years and the mean age of the women 68.2 +/- 12 years. As to the main risk factors of coronary atherosclerosis arterial hypertension was present in 48%, smoking in 42%, diabetes in 23% and hyperlipoproteinaemia in 31% of the treated patients. More than one third of the patients had a history of myocardial infarction (38%). The infarcted artery was the r. interventricularis anterior (LAD) in 51 (40.2%), the right coronary artery (RCA) in 54 (42.5%), the r. circumflex (LCX) in 16 (12.6%), the left main coronary artery in 2 (1.6%) and the bypass in 4 (3.1%). Multiple coronary affections were recorded in 80 (63%) patients, affections of one artery in 47 (37%). Primary procedural success (flow TIMI 3/2) was achieved in 121 patients (95.3%). Normal flow through the infarcted artery TIMI 3 was achieved in 118/127 (85.8%) patients. In 91 (71.7%) into the infarcted artery a coronary stent was implanted, during hospitalization no subacute stenosis of the stent developed. The mean period between the onset of infarction pain--injection was 4.4 +/- 2.3 hours. The mean period of the entire procedures was 48 +/- 14.5 minutes. As contrast material only non-ionic contrast substances were used (Iomeron 350) with a mean consumption of 150 ml per patient. The mean skiascopic time was 13.6 +/- 1.8 min. A total of 9 (7.1%) patients were treated with GP IIb/IIIa receptor blockers (abciximab). The total hospitalization mortality of the intervened group was 7.1% (9 patients). In a sub-group of 9 patients who at the onset of the procedure were in cardiogenic shock 3 (33%) died. The hospitalization mortality of the sub-group of patients with AIM without cardiogenic shock, treated with d-PTCA was 5.1% (6/118). During hospitalization the authors did not observe any intracranial haemorrhage.

DISCUSSION

The group of subjects with AIM subjected to catheterization who are treated by d-PTCA is relatively numerous in our department. According to a number of clinical studies successful d-PTCA in AIM gives better short-term and long-term results as compared with thrombolytic therapy. The primary success rate of d-PTCA was high and the hospital mortality was low and comparable with contemporary data in the literature.

CONCLUSION

Direct PTCA is effective treatment in patients with acute myocardial infarction. The authors results confirm the high procedural success rate and acceptable hospital mortality. These favourable results of an invasive approach to treatment of AIM must be compared in future with bolus thrombolytic treatment by new types of thrombolytic preparations in combination with anti-platelet treatment with blockers of platelet glycoprotein receptors IIb/IIIa with/or without subsequent percutaneous coronary intervention.

[24-hour ambulatory blood pressure monitoring]

24-hour ambulatory blood pressure monitoring (ABPM) is the exact, fully automatic and noninvasive method for evaluation of the 24-hour hemodynamic profile of the subject by multiple and regular blood pressure and heart rate measurement. In comparison with causal blood pressure measurement, ABPM allows the definition of daytime and nighttime blood pressure averages, diurnal changes of blood pressure, localization of periods of the most frequent appearance of hypertensive values, specification of hypertensive load, percent time elevation and diagnosing of white coat phenomenon. The use of all mentioned findings leads to the improvement of blood pressure control in patients with resistant hypertension, polymorbidity, helps to analyze paroxysmal hypertension, verify diagnosis of the hypertension in patients with borderline or high normal blood pressure. The final profit is the reduction of the target organ damage and reduction of cardiovascular morbidity and mortality. Definite diagnosis of the white coat phenomenon markedly decreases consumption of the antihypertensive drugs. In addition, this method enables better evaluation of hypotensive syndromes and is very helpful in the investigation of physiology of blood pressure regulation, biorhythms and in pharmacodynamical studies of the new antihypertensives.