Biomedical subjects

Michael Holzer

Publications and source records attributed to Michael Holzer.

27 records · Page 2Linked to original sources

PubMed2003

Hypothermia after cardiac arrest: a treatment that works.

PURPOSE OF REVIEW: Sudden death from cardiac arrest is a major health problem that still receives too little publicity. Current therapy after cardiac arrest concentrates on resuscitation efforts because, until now, no specific therapy for brain protection after restoration of spontaneous circulation was available. Therapeutic mild or moderate resuscitative hypothermia is a novel therapy with multifaceted chemical and physical effects by preventing or mitigating the derangements seen in the postresuscitation syndrome. RECENT FINDINGS AND SUMMARY: In 2002, two prospective, randomized studies reported improved outcomes when deliberate hypothermia was induced in comatose survivors after resuscitation from cardiac arrest. However, several issues with regard to resuscitative cooling are still unanswered and should be studied further. These include the optimal timing to initiate cooling, the optimal cooling period, the optimal temperature level, and rewarming strategy. Even important questions, such as which cooling technique will be available in the near future that would combine ease of use with high efficacy, are not answered yet.

Heart Arrest↗

PubMed2003

Therapeutic hypothermia after cardiopulmonary resuscitation.

Full cerebral recovery after cardiopulmonary resuscitation is still a rare event. Unfortunately, up to now, no specific and outcome-improving therapy was available after such events. From several cases it is known that low body and brain temperature during a cardiocirculatory arrest improves the neurological outcome following these events. As it is not possible in acute events to induce hypothermia beforehand, whether cooling after the insult could also be protective was evaluated. After animal studies in the 1990s and first clinical pilot trials of mild therapeutic and induced hypothermia, two randomized trials of hypothermic therapy after successful resuscitation after cardiac arrest were conducted. These studies demonstrated that hypothermia after cardiac arrest could improve neurological outcome as well as overall mortality.

Animals↗

PubMed2002

Mortality of patients with pulmonary embolism.

BACKGROUND: Pulmonary embolism (PE) is a potentially fatal disorder with highly varying mortality rates. To provide information that is more precise for prospective intervention studies, we analysed the data of our patients with PE, defining clinically relevant subgroups with respect to their individual mortality rates. METHODS: We studied 283 consecutive patients with confirmed PE diagnosis, with respect to demographic data, risk factors for thromboembolic disease and clinical signs. In addition, diagnostic and therapeutic interventions such as blood gas analysis (BGA), lactate and D-dimer determination, electrocardiography (ECG), echocardiography, spiral computer tomography (Spiral CT), ventilation/perfusion lung scintigraphy (V/Q-Scan), thrombolytic therapy, mechanical ventilation, and cardiopulmonary resuscitation (CPR), were accounted for. Study endpoint was mortality rates on day three. RESULTS: Overall, mortality rate was 15% (42 of 283). Mortality rates differed considerably; 95% of patients with cardiac arrest on arrival (21 of 22), 85% of patients with cardiac arrest--not in hospital (28 of 33), 80% of patients receiving mechanical ventilation (40 of 50), 77% of patients needing cardiopulmonary resuscitation within the first 24 hours (37 of 48), 37% of patients with syncope (18 of 49), 30% of patients receiving thrombolytic treatment (25 of 87), 26% of patients on whom lactate measurement was performed (36 of 139), 18% of patients on whom blood gas analysis was done (35 of 197), 17% of patients on whom echocardiography was performed (34 of 195), 8% of patients with twelve complete lead ECG recordings (21 of 262) and D-Dimer determination (12 of 148), 2% of patients tested on Spiral CT (5 of 226) and 1% where a V/Q-Scan was performed (1 of 74). CONCLUSION: Patients with PE who received mechanical ventilation, cardiopulmonary resuscitation, and thrombolytic treatment had very high mortality rates of 80, 77 and 30% respectively. However, patients stable enough for diagnostic procedures as Spiral CTs and V/Q-Scans had mortality rates of 1 to 2%. These facts are to be considered when planning pulmonary embolism intervention trials in which reduction of mortality is a defined endpoint.

Adult↗

PubMed2002

Severe accidental hypothermia with or without hemodynamic instability: rewarming without the use of extracorporeal circulation.

BACKGROUND: The optimal rewarming technique for patients in deep accidental hypothermia with core temperatures below 28 degrees C is not established. Several authors believe that extracorporeal rewarming is essential, especially for patients with hemodynamic instability. Others believe that invasive rewarming ought to be reserved for patients in cardiac arrest. We describe our experience with a strictly conservative technique without the use of invasive rewarming devices in patients with severe accidental hypothermia and a sustained perfusion rhythm. METHODS: A cohort study extending from 1991 to 2000, including all patients received at the emergency department of the University Hospital of Vienna with severe hypothermia, a core temperature of maximum 28 degrees C and no preclinical cardiac arrest. RESULTS: 36 patients with deep hypothermia were included in the study. Their core temperatures ranged from 20.2 degrees C to 28 degrees C; the median temperature was 25.75 degrees C (25th and 75th percentile, 24.2/27.3). Fourteen patients were intoxicated and their multimorbidity was high. All of 19 patients with stable hemodynamics and 14 of 17 patients with unstable hemodynamics were successfully rewarmed to normothermia with warmed infusions, inhalation rewarming and forced air rewarming. The rewarming process took 9.5 hours (8/10.5) and required a volume load of 4820 ml (2735/5770). The rewarming rate was 1.09 degrees C per hour (0.94/1.25). Although 92% of the patients were successfully rewarmed to normothermia, in-hospital mortality was 42%, but was largely related to comorbidity. DISCUSSION: A conservative approach is highly successful in achieving normothermia in patients with deep hypothermia with or without stable hemodynamics. In-hospital mortality of severe accidental hypothermia in urban conditions is high; comorbidity might play a major role. The influence of the rewarming strategy on late in-hospital mortality remains unclear.

Austria↗

PubMed2002

Plasma endothelin in patients with acute aortic disease.

PURPOSE AND BACKGROUND: We investigated the plasma levels of endothelin 1/2 in patients with acute symptoms relating to a known or newly diagnosed aortic aneurysm in order to investigate the possible role of peptides in the development of the disease. METHODS: Endothelin 1/2 plasma levels were determined in patients admitted to the emergency unit with suspected acute aortic disease. The history, type of aneurysm, outcome and laboratory findings were determined and compared to endothelin 1/2 levels collected on admission. RESULTS: In patients with ruptured aneurysm (n=27) or acute aortic dissection (n=18) the endothelin 1/2 median levels were higher 1.1 (25th and 75th quartile 0.7, 1.7) fmol/ml than in patients (n=20) with pre-existing aneurysm 0.7 (0.4, 1.1) fmol/ml (P=0.013). Patients who died had significantly higher endothelin levels 1.3 (0.8, 1.9) fmol/ml than the survivors 0.8 (0.5, 1.4) fmol/ml (P=0.04). In a logistic regression analysis, only a higher blood pressure on admission was an independent predictor of survival. CONCLUSION: Endothelin 1/2 levels are elevated in patients with acute dissection or ruptured aneurysm, but they are not an independent predictor of survival.

Adult↗

PubMed2002

Intra-aortic balloon counterpulsation in the emergency department: a 7-year review and analysis of predictors of survival.

BACKGROUND: Intra-aortic balloon pump (IABP) counterpulsation in cardiogenic shock (CS) is suggested as bridging therapy to definite emergency revascularization, heart transplantation and acute valvular repair. Data concerning the use of IABP counterpulsation in an emergency department (ED) are rare. PATIENTS AND METHODS: We reviewed retrospectively the charts of patients who had been treated by IABP counterpulsation in the ED of a tertiary care university hospital during a 7-year period. We analyzed indications for IABP treatment, complications of IABP use and studied various predictors for 30-day survival. RESULTS: Overall 88 (68 male) patients, median age 60 years (IQR 53-69 years) were treated with IABP counterpulsation. CS was caused by acute coronary syndrome (ACS), acute cardiomyopathy decompensation of (CMP) and aortic stenosis (AS) in 77 (87%), ten (12%) and one (1%) patients, respectively. Complications attributed to the insertion or maintenance of IABP were observed in nine (10%) patients. Thirty four patients (38%; 24 male) survived. Compared to non-survivors, these patients were younger (56 vs. 63 years; P<0.023) and had significant lower serum lactate levels before IABP insertion (3 vs. 5.5 mmol/l; P<0.002). Logistic regression analysis identified age (P<0.04) and serum lactate serum level before IABP (P<0.01) as independent predictors for survival. In the 77 patients with ACS PTCA tended to be associated with a higher rate of survival (P<0.09). CONCLUSION: Initiation of IABP counterpulsation in patients with CS in an ED appears safe. Low levels of serum lactate and younger age were independent predictors of survival. In patients with ACS PTCA may contribute to improved outcome.

Acidosis, Lactic↗

PubMed2002

Survivors of ventricular tachyarrhythmias due to a transient or reversible disorder have a high recurrence rate of lethal cardiac events.

OBJECTIVES: The recurrence rate of lethal cardiac events after the survival of a primary cardiac arrest in patients not having received an implantable cardioverter defibrillator (ICD) is investigated. BACKGROUND: According to current guidelines, only a small percentage of patients after successful cardiopulmonary resuscitation due to an underlying cardiac problem are eligible for the implantation of an ICD. METHODS: For retrospective analysis, we used a data registry of patients admitted to an emergency department after cardiac arrest. Patients who had a primary cardiac cause for their cardiac arrest and who did not die within the first month after successful restoration of spontaneous circulation were selected. RESULTS: From 1246 patients, 360 met the inclusion criteria. A second lethal cardiac event occurred in 94 (26%). Of those 94 patients, 57 (61%) had good neurological function before their second cardiac arrest. Of the survivors with good neurological function, 47 (82%) did not have an ICD or a cardiac transplant. Another cardiac arrest due to a primary cardiac event occurred in 34 (72%) of these patients. CONCLUSIONS: Cardiac arrest survivors without an apparent indication for an ICD have a high risk of suffering from a re-arrest of cardiac origin.

Aged↗

PubMed2002

Endothelin-1 elevates regional cerebral perfusion during prolonged ventricular fibrillation cardiac arrest in pigs.

Since adrenaline (epinephrine) also has negative effects during and after cardiopulmonary resuscitation (CPR) a non-adrenergic vasoconstrictor like endothelin might be an alternative to increase vital organ blood flow. We studied the effect of different doses of endothelin-1 compared with adrenaline on the ability to resuscitate, cerebral and myocardial blood flow (MBF) in a closed chest cardiac arrest pig model. After 5 min of ventricular fibrillation, CPR with a ventilator and a mechanical compression device was started. At 10 min, 31 pigs were randomized to receive a single dose of endothelin-1 50, 100 or 200 microg or repeated doses of adrenaline 0.04 mg kg(-1) or saline every 3 min. After 25 min, the pigs were defibrillated to achieve restoration of spontaneous circulation. Blood flow was measured with the fluorescent microsphere method. In animals receiving endothelin-1 50, 100 and 200 microg the cerebral blood flow (CBF) increased from median 28 (25th; 75th quartile: 16; 40), 32 (15; 48) and 17 (4; 65) to 36 (31; 54), 47 (39; 57) and 63 (35; 83) ml min(-1) per 100 g, respectively, 6 min after drug administration (P<0.05 endothelin-1 50 microg vs. Control, P<0.01 endothelin-1 100 and 200 microg vs. Control). At the same time CBF decreased in the control and adrenaline group from 36 (21; 41) and 39 (15; 50) to 12 (2; 25) and 24 (15; 26) ml min(-1) per 100 g, respectively, (P<0.05 adrenaline vs. endothelin-1 200 microg). There was no difference in MBF between the treatment groups despite a higher coronary perfusion pressure (CoPP) in the endothelin-1 groups. Restoration of spontaneous circulation could be only achieved in the endothelin-1 50 microg (3 of 7; 43%) and 100 microg (5 of 7; 71%) group. This study suggests that endothelin-1 enhances CBF during CPR better than adrenaline and increases resuscitation success.

Animals↗

PubMed2000

Deterministic nonlinearity in ventricular fibrillation.

We provide numerical evidence that the electrocardiogram data collected from pigs during induced ventricular fibrillation cannot be described by a monotonic nonlinear transformation of linearly filtered noise. To establish this we use surrogate techniques and apply two test statistics: (1) the Takens' maximum likelihood estimator of the Grassberger-Procaccia correlation dimension and (2) an improved correlation dimension estimation routine. The improved dimension estimates provide evidence that the correlation dimension of the underlying dynamics during the episode of VF in the first 30 s is slightly less than 6. This result is consistent and reproducible among subjects. (c) 2000 American Institute of Physics.

Journal Article↗