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Biomedical subjects

J Lerman

Publications and source records attributed to J Lerman.

At least 145 records · Page 8Linked to original sources
PubMed1984

Intraoperative failure of a Fluotec Mark II vapourizer.

A case report describing the failure of a Fluotec Mark II vapourizer to deliver the indicated anaesthetic concentration during surgery is presented. The failure was caused by a broken internal circlip which resulted in most of the fresh gas flow bypassing the vapourizer. The inspired halothane concentration was reduced to 0.1 per cent, irrespective of the vapourizer dial setting. This type of vapourizer failure may be identified by the unusually loose dial on the Mark II vapourizer. The complications resulting from a light level of anaesthesia include awareness, systolic and diastolic hypertension, movement, and their sequelae.

Adolescent↗
PubMed1984

Age and solubility of volatile anesthetics in blood.

The more rapid rate of rise of alveolar anesthetic partial pressure in children compared with adults may be explained in part by an increasing solubility of volatile anesthetics in blood with age. To investigate this possibility, the authors measured the blood-gas partition coefficients of isoflurane, enflurane, halothane, and methoxyflurane in four groups of fasting subjects: 10 full-term newborns (at delivery), 11 children (3-7 years old), 11 adults (20-40 years old), and 10 elderly adults (75-85 years old). The blood-gas partition coefficients were greatest in adults: isoflurane 1.46, enflurane 2.07, halothane 2.65, and methoxyflurane 16.0; and least in newborns: 1.19, 1.78, 2.14, 13.3, respectively. The blood-gas partition coefficients in children (1.28, 1.78, 2.39, 15.0, respectively), which were intermediate between those in newborns (P less than 0.005) and those in adults (P less than 0.005), were not significantly different from those in elderly adults (1.29, 1.79, 2.41, 15.0, respectively). The blood-gas partition coefficients of both isoflurane and enflurane correlated directly with the serum albumin and triglyceride concentrations; that of halothane correlated directly with the serum cholesterol, albumin, triglyceride, and globulin concentrations; and that of methoxyflurane correlated directly with the serum cholesterol, albumin, and globulin concentrations. The authors conclude that age significantly affects blood-gas partition coefficients, and the lower blood-gas partition coefficients in children explain in part the more rapid rise of alveolar anesthetic partial pressure in this age group.

Adult↗
PubMed1984

Hematocrit and the solubility of volatile anesthetics in blood.

To clarify the effect of hematocrit on the solubility of volatile anesthetics in blood, we measured the blood-gas partition coefficients of isoflurane, enflurane, halothane, and methoxyflurane concurrently at 37 degrees C in blood from four adults. We measured the blood-gas partition coefficients in the plasma (hematocrit 0%) and packed red cell fractions (hematocrit 80%), and in four mixtures of these two fractions (hematocrits 10%, 25%, 40%, and 55%). The mixtures were prepared by recombining appropriate amounts of plasma and packed red cells from each adult. As hematocrit increased, the blood-gas partition coefficient of isoflurane decreased linearly (P less than 0.01), whereas that of enflurane increased linearly (P less than 0.05). The partition coefficient for isoflurane in plasma was 20% greater than that in packed red cells, whereas the partition coefficient for enflurane in plasma was 10% less than that in packed cells. The blood-gas partition coefficients of halothane and methoxyflurane did not change significantly between measurements in plasma and packed red cells. We conclude that hematocrit exerts a statistically significant effect on the blood-gas partition coefficient of isoflurane and enflurane.

Adult↗
PubMed1983

The heart rate response to succinylcholine in children: a comparison of atropine and glycopyrrolate.

To determine whether intravenous atropine and glycopyrrolate are equally effective in preventing succinylcholine-induced heart rate changes, we studied the heart rate during the first 78 seconds of anaesthesia in 40 children anaesthetized with either thiopentone, atropine (0.02 mg X kg-1) and succinylcholine (2 mg X kg-1), or thiopentone, glycopyrrolate (0.01 mg X kg-1) and succinylcholine (2 mg X kg-1). Each treatment group was divided into four subgroups which differed only in the interval (6, 10, 15, 20 seconds) between injection of atropine or glycopyrrolate and succinylcholine. During the 54 seconds after succinylcholine, the mean heart rate of each subgroup decreased transiently and then returned to the pre-induction heart rate or higher. There was no difference in either the magnitude or the duration of the decrease in heart rate or the subsequent increase in heart rate between respective subgroups. Bradycardia occurred in only two patients, both of whom received glycopyrrolate. We conclude that atropine (0.02 mg X kg-1) and glycopyrrolate (0.01 mg X kg-1) are equally effective in attenuating succinylcholine-induced changes in heart rate in children.

Anesthesia, General↗
PubMed1983

Anesthetic requirements for halothane in young children 0-1 month and 1-6 months of age.

In a previous study, the authors found that infants, in the first 6 months of life, required the highest minimum alveolar concentration (MAC) of any age group (1.09% halothane). Because only two neonates (0-31 days of age) were included in the original study and because profound depression of blood pressure and heart rate have been reported in neonates, the authors determined 1) whether the MAC of halothane in neonates (n = 12) differs from that in infants (1-6 months of age) (n = 12) and 2) whether the blood pressure and heart rate responses in neonates differ from those in infants at approximately 1 MAC. The authors found that the MAC of halothane in neonates, 0.87% +/- 0.03 SEM, was significantly lower (P less than 0.01) than that in infants, 1.20% +/- 0.06 SEM. With induction of anesthesia, the systolic blood pressure decreased 23% in neonates (P less than 0.05) and 34% in infants (P less than 0.005) from awake values. Similarly, the heart rate decreased 12% in neonates and 22% in infants (P less than 0.05). The incidence of hypotension (greater than 30% decrease in systolic blood pressure from awake) in neonates, 33%, was not significantly different from that in infants, 44%. The authors conclude that the MAC of halothane in neonates is 25% less than that in infants and significantly less than was thought previously. The MAC in infants is the highest of any age group. The decrease in blood pressure and the incidence of hypotension in neonates are similar to those in infants at approximately 1 MAC of halothane.

Age Factors↗
PubMed1983

Osmolarity determines the solubility of anesthetics in aqueous solutions at 37 degrees C.

The authors determined whether they could predict accurately the solubility of anesthetics in aqueous solutions at 37 degrees C, knowing the osmolarity and the pH of the solution and the solute composition. The partition coefficients of the four volatile anesthetics, isoflurane, enflurane, halothane, and methoxyflurane, were determined concurrently at 37 degrees C between air and aqueous solutions containing sodium chloride, dextrose, mannitol, or heparin. The osmolarities of these solutions ranged from 0 to 7,000 mOsm/l. The partition coefficients decreased linearly with increasing osmolarity when plotted on a semilogarithmic scale. The effect of osmolarity on the partition coefficient of the alkane anesthetic, halothane, was 20% less (P less than 0.001) than the effect of osmolarity on the partition coefficients of the three methyl-ethyl ether anesthetics, isoflurane, enflurane, and methoxyflurane. The solubility of anesthetics in aqueous solutions did not depend on either the molecular structure of the solute or the pH of the solution. The solubility of volatile anesthetics in aqueous solutions at 37 degrees C is inversely and predictably dependent on the osmolarity of the solutions.

Anesthetics↗
PubMed1981

Effects of nitrates on R-wave variations after exercise in coronary heart disease: differences in patients with and without angina pectoris.

With the purpose of investigating the pathophysiology of changes in the R wave after exercise and its relationship with left ventricular function, we studied 44 patients with coronary heart disease. They were classified into the following three groups: group A, 11 patients with angina pectoris and no prior myocardial infarction; group B, 18 patients with angina pectoris and prior myocardial infarction; and group C, 15 patients with prior myocardial infarction but no angina. All patients performed two exercise tests; one was a control test, and the other was performed after the sublingual administration of 5 mg of isosorbide dinitrate. In group A, variations in the R-wave voltage in control test and in the test after isosorbide dinitrate were 1.5 +/- 0.8 mm and -1.2 +/- 0.9 mm (P less than 0.05), respectively. In group B, results were 1.2 +/- 0.7 mm on the control test and -0.7 +/- 0.6 mm after isosorbide dinitrate (P less than 0.002), and in group C were -1.6 +/- 1.2 mm on the control test and -0.7 +/- 0.7 mm after isosorbide dinitrate (not significant). Thus, the two groups of patients with angina showed an increase of the R-wave after exercise in the control test but a decrease after the administration of nitrates, whereas the patients without angina showed a reduced R-wave after exercise both before and after the administration of nitrates (like normal subjects). This study suggests that ischemic ventricular dysfunction with exercise results in an increase in the R-wave, while exercise after nitrates results in a decrease in the R-wave consistent with less or no ventricular dysfunction due to nitrate therapy.

Administration, Topical↗
PubMed1977

Progressive ambulation and treadmill testing of patients with acute myocardial infarction during hospitalization: a feasibility study.

Symptoms, signs, hemodynamic and electrocardiographic responses of 12 patients with acute myocardial infarction were studied before, during and after three activities: activity I, sitting upright; activity II, walking to the adjacent toilet; and activity III, walking on a treadmill set at 1.2 mph (1.9 km/hr) at 0, 3 and 6% successive gradients. The three activities were studied respectively at three, six and ten days (means) after infarction. Weakness was the most commonly occurring symptom. Mean systolic blood pressure fell 9 mm Hg upon assumption of the upright position (activity I) and was sustained for the five minutes of sitting. The systolic blood pressure drop was only 3.5 mm Hg with activity II. During activity III, one patient developed angina. Between rest and the 6% treadmill gradient, systolic blood pressure, heart rate and pressure-rate product rose 29 mm Hg, 26 beats/minute and 64 units, respectively. Electrocardiographic evidence of ischemia was observed in two patients during activity I, in two patients during activity II, and in one patient during activity III, but was insufficient for stopping the activities. Similarly, two patients developed minor arrhythmias, one with activity I and one with activity III. The use of this low-level treadmill test before discharging the patient from the hospital proved to be safe and feasible for obtaining objective data to assess the patients' ability to perform activities requiring equal exertion at home. Successful performance of these three activities before leaving the hospital should provide useful criteria for discharge of a patient with myocardial infarction.

Aged↗
PubMed1977

Renal failure and interstitial nephritis due to trichloroethylene anesthesia and high-dose penicillin.

An unusual case of acute renal failure is described. The patient, who had no previous history or signs of renal impairment, underwent lumbar laminectomy under general anesthesia with trichloroethylene (Trilene) and nitrous oxide. On the fifth postoperative day i.v. administration of 12 million units of penicillin was started. Within 16 h the patient developed oliguria and a clinical picture of acute renal failure. The course of the disease was prolonged and necessitated four hemadialysis treatments. The patient recovered only about 50% of his renal function. A biopsy performed two months after the onset of the acute renal failure was interpreted as indicating tubulo-interstitial nephritis. The role of trichloroethylene in the etiology of acute renal failure is discussed.

Acute Kidney Injury↗
PubMed1976

Correlation of polarcardiographic criteria for myocardial infarction with arteriographic and ventriculographic findings (substantiation of transmural and presentation of non-transmural criteria).

Sensitivity and specificity of polarcardiographic criteria for myocardial infarction were compared with those of electrocardiographic criteria in 108 patients with chest pain syndromes who were referred for coronary arteriography and left ventriculography. With the combination of total occlusion of at least one coronary artery and abnormal systolic contraction of at least part of the left ventricle as the best available documentation of myocardial disease, sensitivity and specificity were 70% and 67%, respectively, using electrocardiographic criteria and 80% and 73% using polarcardiographic criteria, for both anterior and inferior myocardial infarction. Another polarcardiographic criterion--rightward shift in R latitude at 10 msec after onset of QRS--occurred concurrently with vessel occulusion in 16 of 17 patients (94%), in four of whom this was the only objective evidence of myocardial infarction, and three of whom there was no manifest abnormality of wall contraction. This criterion is considered evidence of non-transmural myocardial infarction, probably in the subendocardial layer near the apex of the left ventricle. When such evidence is added, sensitivity of polarcardiographic criteria increased to 84%, and specificity decreased to equal that of the electrocardiographic criteria (67%).

Adult↗
PubMed1976

Low-level dynamic exercises for earlier cardiac rehabilitation: aerobic and hemodynamic responses.

Three different kinds of low-level exercise (one arm and two leg exercises) and a low-level treadmill test were designed for patients recovering from acute myocardial infarction; noninvasive circulatory and aerobic responses to these activities were evaluated in healthy subjects. Exercise systolic pressure-rate product (X 10(-2)) were, respectively, 92 +/- 16, 98 +/- 10, 106 +/- 22 and 129 +/- 17 for the four activities studied. Exercise metabolic rates were 1.56 +/- 0.16, 1.99 +/- 0.22, 1.68 +/- 0.25 and 2.74 +/- 0.32 METS (multiples of the observed resting oxygen requirements). Additionally, arteriovenous oxygen difference, cardiac output, stroke volume, mean systemic and mean pulmonary pressures were measured in four coronary patients as they performed the leg exercises. It is hoped that this study will provide a basis for applying these different forms of exercise to patients recovering from an acute myocardial infarction, even when they are confined to bed, in order to advance the onset of cardiac rehabilitation. In a similar way, the new low-level treadmill test may be indicated for the same patients to assess the safety of discharging them from the hospital and permitting unsupervised ambulatory activity at home.

Adult↗