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Biomedical subjects

B Sorensen

Publications and source records attributed to B Sorensen.

At least 19 recordsLinked to original sources

Peribulbar anesthesia. Effect of bicarbonate on mixtures of lidocaine, bupivacaine, and hyaluronidase with or without epinephrine.

The pH-adjustment of local anesthetic solutions with sodium bicarbonate may shorten onset time and improve spread of neural blockade. The authors undertook a prospective, double-masked, randomized study to see if a pH-adjusted mixture of lidocaine, bupivacaine, and hyaluronidase had faster and more complete onset of neural blockade, when used for peribulbar anesthesia. Eighty patients were randomly assigned to four groups and received a peribulbar block with one of four mixtures: group 1 (L) = 2% lidocaine, group 2 (LPH) = 2% lidocaine with 0.06 meq/ml sodium bicarbonate, group 3 (LE) = 2% lidocaine with 1:100,000 epinephrine (commercially prepared), or group 4 (LEPH) = 2% lidocaine with 1:100,000 epinephrine with 0.06 meq/ml sodium bicarbonate. To 5 ml of each of the preceding groups, 5 ml of 0.75% bupivacaine and 150 units of hyaluronidase was added. After each block, extraocular muscle movement was followed in each quadrant until akinesia developed. In the event of incomplete akinesia, blocks were supplemented at 20 minutes. The LPH group had the fastest onset to complete akinesia (7.0 +/- 2.0 minutes, mean +/- SEM) when compared with the onset time of all other groups (group 1 = 11.5 +/- 1.9 minutes, group 4 = 13.1 +/- 1.4 minutes, and group 3 = 16.0 +/- 1.8 minutes, significance greater than 95% by analysis of variance). Furthermore, when compared with group 3 by analysis of variance, group 4 had a faster onset time. The authors conclude that pH-adjustment of solutions with bicarbonate of either lidocaine/bupivacaine/hyaluronidase or commercially prepared lidocaine with epinephrine/bupivacaine/hyaluronidase decreases the onset time of peribulbar anesthesia.

Anesthesia, Local

[Compression of the right pulmonary artery by a dissecting aneurysm of the ascending aorta. Apropos of a case occurring long after aortic valve replacement].

The authors report the case of a dissecting aneurysm of the ascending aorta compressing the right pulmonary artery in a 62 year old man, 6 years after aortic valve replacement. The clinical presentation was that of pulmonary embolism. The diagnosis was confirmed by angiopneumography and CT scanning. The ascending aorta was successfully replaced with a Dacron prosthesis. One other case was found in a review of the literature. After discussing the predisposing factors of aortic dissection during cardiac surgery, the authors underline the diagnostic value of CT scanning in cases of suspected aneurysms of the thoracic aorta.

Aortic Dissection

[Coronary occlusion immediately following a successful coronary angioplasty. Treatment by repeat angioplasty].

The authors report the case of a 52 year old patient with a significant stenosis of the medial portion of the left anterior descending artery (LAD) with excellent left ventricular function. Transluminal coronary angioplasty (TCA) was indicated following a positive exercise stress test. This was initially performed successfully. Fifteen minutes after the end of the procedure, a total obstruction occurred at the site of dilatation immediately eliciting significant precordial chest pain and massive elevation of the ST segment. Isosorbide dinitrate (ISDN) at a dose of 2 mg was injected into the artery 3 times without success as was an attempt to pass through the obstruction with a guide wire. Another TCA was then attempted without administration of the thrombolytic agent. The dilating catheter passed easily by the obstruction permitting several dilatations which restored rapid coronary artery flow, relieved completely the chest pain, and normalized electrocardiographic abnormalities. This procedure represents a new therapeutic approach to obstruction, an often unpredictable and serious complication of coronary angioplasty in the absence of collateral circulation, thereby preventing the development of a myocardial infarction and an emergency aortocoronary bypass operation.

Acute Disease

Cardiac function and hypercarbia.

In 12 patients with heart disease, hypercarbia was induced for carotid endarterectomy. Anesthesia was maintained with nitrous oxide in oxygen and methoxyflurane. In addition to intra-arterial measurements of blood pressure, cardiac output, systolic time intervals (STI), and pressure time indices (PTI) were determined in order to assess cardiovascular responses in these patients. Internal carotid stump blood pressure was measured in five patients before and after induction of hypercarbia. Mild elevation of the Paco2 level affected systolic time intervals but not heart rate and blood pressure. When Paco2 levels reached 56 to 65 torr, systolic but not diastolic blood pressure rose significantly, heart rate and cardiac output increased, while the shortening in the preejection period (PEP), left ventricular ejection time (LVET), and the decrease in the PEP/LVET ratio signified increased mechanical cardiac activity. Hypercarbia caused intense sympathetic stimulation as demonstrated by twofold to threefold increases in plasma catecholamine levels. Stump blood pressure was elevated. Cardiac oxygen demand was significantly increased, while coronary filling time was shortened, as indicated by the increase in the tension time index and shortening in the diastolic time. This signified a relative myocardial underperfusion. Thus, while hypercarbia to levels of 66 to 70 torr increased internal carotid artery stump pressure, it also caused increased cardiac mechanical activity and concomitant unfavorable balance between myocardial oxygen consumption and supply. The measurement of STI and the computation of PTI provided early detection of alterations in cardiac function.

Aged

The postanesthetic antiemetic effect of premedication with dehydrobenzperidol before ether anesthesia.

A study was performed to evaluate the antiemetic effects after ether anesthesia when dehydrobenzperidol (DHB) and pentobarbital were used for premedication and to compare these effects with halthane anesthesia when pentobarbital was used as premedication. Eighty-four patients undergoing minor surgical operations were randomly divided into three groups. The patients received ether and ether DHB 0.2 mg/kg or pentobarbital 2 mg/kg for premedication, or halothane and pentobarbital 2 mg/kg for premedication. The complaints of nausea and vomiting were recorded 24 h after anesthesia. We found that DHB compared to pentobarbital had a greater antiemetic effect after ether anesthesia, but the difference was not significant (P greater than 0.05). However, if only persistent nausea and vomiting were considered, the difference was significant (P less than 0.05). The incidence of nausea/vomiting after ether anesthesia with DHB as premedication was a little higher compared to halothane anesthesia with pentobarbital as premedication, but the difference was not significant (P greater than 0.05). However, if only persistent nausea/vomiting was considered, the incidence of complaints was equal in the two groups. It is concluded that when used for premedication to ether anesthesia DHB seems to lead to less postanesthetic nausea/vomiting than pentobarbital. Further DHB seems able to reduce the incidence of nausea/vomiting after ether anesthesia roughly to the level of that seen after pentobarbital premedication for halothane anesthesia.

Adolescent

Supraphysiological glucocorticoid treatment in hypoxic stress in dogs.

Effects of supraphysiologic methylprednisolone succinate doses on systolic time intervals, hemodynamic performance, and metabolism were studied in normal dogs during normoxia, after 60 min of normocapnic hypoxemia (PAO2 = 30 mm Hg), and reoxygenation. Bolus injections of 30 or 100 mg/kg methylprednisolone did not exert any positive inotropic action during normoxia. Cardiovascular and metabolic changes induced by hypoxia were modified only to a modest and statistically insignificant degree by sustained high levels of methylprednisolone.

Animals

Changes in cardiac function during and after pregnancy expressed by systolic time intervals.

Hemodynamic changes during the first and third trimester in pregnancy and in the first week of puerperium were evaluated by non-invasive measurements of Systolic Time Intervals (STI) in supine and left lateral position. The Pre-ejection Period (PEP) was found to shorten significantly in pregnancy and the puerperium due to the increased blood volume. The electro-mechanical systole (QS2) and left ventricular ejection time (LVET) were shortened too, while PEP/LVET-ratio was increased in the third trimester due to the mechanical compression of the gravid uterus on the inferior vena cava. A lengthening of QS2 and LVET and a decreased PEP and P/L-ratio were demonstrated in the third trimester in lateral position when the pressure of the enlarged uterus was eliminated. Heart rate (HR) increased in late pregnancy as well as after delivery, while arterial blood pressure (BP) only underwent minor changes. Employment of the STI seems to provide more useful information about the changes cardiac function during gestation than HR and BP does. The measurements of STI can be repeated without any risk or inconvenience to the patients.

Adult

Modern aspects of shock-treatment in extensive burns (author's transl).

The best fluid-treatment is not yet found. Even the optimal fluid-treatment, however, can hardly be expected to entail drastic improvements of the prognosis in patients suffering from severe burns. Interest should be concentrated on the burned tissue. We believe to have proved that acute excision in the shock-phase is permissable.

Acute Disease