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Biomedical subjects

Michael Shochat

Publications and source records attributed to Michael Shochat.

7 recordsLinked to original sources
PubMed2006

Prediction of cardiogenic pulmonary edema onset by monitoring right lung impedance.

OBJECTIVE: To evaluate the ability of internal thoracic impedance (ITI) monitors to predict cardiogenic pulmonary edema in patients at risk. DESIGN AND SETTING: Prospective, controlled multicenter study. PATIENTS: We examined 328 consecutive patients admitted for cardiac conditions. Of these 265 patients aged 27-83 years with no clinical signs of pulmonary edema, extracardiac respiratory failure or pacemakers comprised the study cohort. INTERVENTION: Monitoring of the lung's electrical impedance was used for predicting cardiogenic pulmonary edema since accumulation of blood and fluid decreases impedance values. MEASUREMENTS AND RESULTS: Impedance of the lung is the main feature of ITI measured by the RS-207 monitor: decreased ITI prior to the clinical signs of cardiogenic pulmonary edema was used as the prediction criterion. The clinical signs used for confirmation of its prediction were dyspnea, cyanosis, pulmonary rales, crepitations, arterial hypoxemia, and radiographic evidence of pulmonary congestion in chest radiographs. Clinicians were blinded to the results of ITI measurements and radiologists were blinded to both ITI and clinical data. Thirty-seven patients developed cardiogenic pulmonary edema while being monitored. ITI decreased by more than 12% of baseline in all of them; this occurred at 30 min or longer (26 patients) and at 60 min or longer (11 patients) before the appearance of clinical signs. ITI fell by less then 10.1% of baseline in all 228 patients who did not develop the edema. CONCLUSION: Monitoring ITI is suitable for early prediction of cardiogenic pulmonary edema, before the appearance of the clinical signs.

Adult↗
PubMed2005

Relation of left atrial size to function as determined by transesophageal echocardiography.

One hundred thirty-nine patients who underwent transesophageal echocardiographic studies were grouped by their maximal left atrial (LA) volumes, and their stroke volumes, emptying fractions, and fractional shortening were calculated. In large atria, an inverse relation was found between further increases in LA volume and LA function, determined by emptying fractions and fractional shortening.

Atrial Function, Left↗
PubMed2005

Fluid overload contributing to heart failure.

BACKGROUND: In advanced heart failure, the compensatory responses to reduced cardiac output, in spite of fluid retention, lead to maladaptive consequences. METHODS: We performed a Medline survey for fluid overload and heart failure as well as reviewing textbook chapters. RESULTS: The increased sympathetic nervous system, renin-angiotensin-aldosterone system, and antidiuretic hormone stimulation and release lead to a vicious cycle--augmenting pre-load, contractility and after-load, as well as increased fluid overload. The elevated work load on an already failed cardio-circulatory system results in further deterioration. Plasma volume is usually increased in untreated patients with increased extracellular fluid. However, it may range from reduced to increased in treated patients. Currently, diuretics remain the initial first line of therapy. In refractory cases, restoring plasma volume and osmolality, by adding albumin or hypertonic saline solutions, neurohormonal antagonists such as vasopressin receptors antagonists, aldosterone antagonists, or administration of nesiritide, may help in overcoming fluid overload. CONCLUSION: Exact measurement of plasma volume in various forms of heart failure and adjusting the treatment accordingly, establishing favourable and detrimental effects of various therapies, and introducing additional and new therapeutic options require further investigation.

Cardiac Output↗
PubMed2005

Haptoglobin polymorphism predicts 30-day mortality and heart failure in patients with diabetes and acute myocardial infarction.

Patients with diabetes presenting with acute myocardial infarction (AMI) have an increased rate of death and heart failure. Patients with diabetes homozygous for the haptoglobin (Hp) 1 allele (Hp 1-1) develop fewer vascular complications. We tested the hypothesis that Hp type is related to the outcome of patients with diabetes presenting with AMI. We prospectively assessed the relationship between Hp type and 30-day mortality and heart failure in 1,437 patients with AMI (506 with diabetes). Multivariate logistic regression identified a significant interaction between Hp type and diabetes status on these outcome measures. Hp type was not related to outcome among patients without diabetes. In contrast, Hp 1-1 was associated with a strong protective effect with regard to the primary end point of death (OR 0.14, P = 0.015) and for death and heart failure (OR 0.35; 95% CI 0.15-0.86, P = 0.018) among patients with diabetes. Finally, among patients with diabetes, Hp 1-1 was associated with smaller infarct size. This study demonstrates that in patients with diabetes and AMI, the Hp type is an important determinant of clinical outcome and infarct size.

Diabetes Mellitus↗
PubMed2004

Utilization of low-profile intra-aortic balloon catheters inserted by the sheathless technique in acute cardiac patients: clinical efficacy with a very low complication rate.

UNLABELLED: Initial intra-aortic balloon pump (IABP) catheters were of large caliber and their utilization resulted in a high incidence of complications, including limb ischemia, bleeding and thrombosis, peripheral neurologic sequelae, and infection. Despite eventual decrease in the size of IABP catheters, the complication rate has remained high. HYPOTHESIS: The study was undertaken to determine whether use of recently available low-profile IABP catheters would result in a lower incidence of vascular and bleeding complications. METHODS: We prospectively evaluated the incidence of complications when consecutively using the low-profile (8F) IABP catheter inserted mostly sheathlessly in 161 acute cardiac patients between January 1, 2000 and April, 2003. RESULTS: Complications encountered included mild transient limb ischemia in two patients (1.2%), minor bleeding episodes in four patients (2.4%), one major puncture site bleeding (0.6%), and a pseudoaneurysm treated percutaneously in two patients (1.2%). Two patients (1.2%) suffered limb ischemia due to embolization or local thrombosis requiring vascular intervention. These complications were milder and their incidence remarkably lower than those reported previously when IABP catheters larger than 8F were used. CONCLUSION: Utilization of low-profile IABP 8F catheters in a sheathless technique entails an exceedingly low complication rate despite an acute presentation, intense anticoagulant and antiaggregant therapy, frequent comorbidity, advanced age, severe coronary disease, and reduced cardiac function in a large proportion of treated patients.

Acute Disease↗
PubMedDate not supplied

Internal thoracic impedance monitoring: a novel method for the preclinical detection of acute heart failure.

BACKGROUND: Acute heart failure (AHF) evolves through two phases. In the first phase, there is interstitial congestion with no clinical sign of edema (preclinical phase); the second, during which lung alveoli begin to fill with fluid, manifests as clinically overt alveolar edema. Treatment of AHF at its preclinical phase can alleviate its clinical impact. Presently, there is no technique that detects the interstitial phase of AHF. We used a device based on a new method of lung bioimpedance measurement. The device measures internal thoracic impedance (ITI), which nearly equals inherent lung bioimpedance. This method can detect small changes in lung fluid that occur during the interstitial stage of AHF. AIM: The objective of this study was to assess the feasibility and efficacy of the said new method in detecting preclinical AHF. METHODS: Internal thoracic impedance and pertinent clinical parameters were monitored for 72 h in 403 patients hospitalized for an acute coronary syndrome without evidence of AHF at study entry. RESULTS: Seventy patients developed AHF during monitoring. Internal thoracic impedance decreased in these patients by 16.4% (95% CI=-12.2% to -20.6%; P<.0001) from the baseline level at 44+/-15.1 min prior to the onset of lung rales. The other 333 patients had no clinical sign of AHF, and their ITI declined only by 4.5% (95% CI=2.5% to -11.5%; P=.3) compared with the baseline level. CONCLUSION: The new method for ITI measurement is sufficiently sensitive in detecting AHF at its preclinical stage. An ITI decrease of more than 12% heralds the appearance of clinically overt AHF and, thus, allows earlier therapy.

Acute Disease↗