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Biomedical subjects

S R Jensen

Publications and source records attributed to S R Jensen.

34 records · Page 2Linked to original sources
PubMed1985

Experimental evaluation and initial clinical application of new self-adhesive defibrillation electrodes.

We evaluated the efficacy of self-adhesive electrode pads for defibrillation and cardioversion in animals and patients. In 11 anesthetized dogs, the success rate of shocks given to terminate electrically-induced ventricular fibrillation was similar for both self-adhesive electrode pads and hand-held electrode paddles; success rate approached 100% at energies of 125-150 joules. Eighty patients undergoing defibrillation or elective cardioversion received shocks from self-adhesive pads. In all but 2 patients defibrillation or cardioversion was achieved at least once using these pads. The pads were equally effective from either apex-anterior or apex-posterior positions. The transthoracic impedance using self-adhesive pads was 75 +/- 21 ohms, similar to transthoracic impedance we previously reported when using standard hand-held paddles. No complications occurred with the use of the pads. We conclude that self-adhesive electrode pads are effective for defibrillation and cardioversion.

Animals↗
PubMed1985

Xeromammography after augmentation mammoplasty.

An 8-year review done of mammography at one institution identified 30 patients who had undergone a previous breast augmentation procedure. Of the 30, six had had silicone injections, 20 silicone-filled implants, and six saline-filled implants. Both free and encapsulated silicone significantly obscured underlying breast tissue because of density and associated calcifications, which would have interfered with detection of subclinical carcinomas. Xeromammography proved useful, however, in clarifying the nature of clinically palpable masses and in studying complications following the breast augmentation procedure.

Adult↗
PubMed1984

Self-adhesive preapplied electrode pads for defibrillation and cardioversion.

The efficacy of self-adhesive electrode pads for defibrillation and cardioversion was assessed in 80 patients who received 267 shocks from self-adhesive pads. In all but two patients, defibrillation or cardioversion was achieved at least once. The pads were equally effective when used in the apex-anterior or apex-posterior position. The transthoracic impedance using self-adhesive pads was 75 +/- 21 ohms (mean +/- standard deviation), which is similar to previously reported transthoracic impedance in defibrillation, using standard hand-held electrode paddles of 67 +/- 36 ohms. It is concluded that self-adhesive electrode pads are effective for defibrillation and cardioversion.

Arrhythmias, Cardiac↗
PubMed1983

Determinants of defibrillation: prospective analysis of 183 patients.

Previous studies have suggested that a number of factors may influence the ability to defibrillate: the transthoracic resistance and resultant current flow, the paddle electrode size, the duration of preshock ventricular fibrillation (VF) and cardiopulmonary resuscitation, metabolic abnormalities, body weight, the shock energy selected, and whether the patient is receiving lidocaine. To examine the effect of these variables, a prospective study was conducted of 183 patients who received direct-current shocks for VF. Overall defibrillation rates approached 90%, even in patients with secondary VF, but rates of successful resuscitation and survival were much lower. Patients who never defibrillated despite multiple shocks had a prolonged duration of cardiopulmonary resuscitation preceding the first shock (21 +/- 14 minutes) and systemic hypoxia and acidosis. These conditions tended to occur in patients who initially had cardiac arrest from causes other than VF: asystole, severe bradycardia and electromechanical dissociation. In such patients, VF developed only as a late event, which was then often unresponsive to attempted defibrillation. The other factors examined were not major determinants of defibrillation.

Body Weight↗
PubMed1983

Effect of ischemia, hypertrophy, hypoxia, acidosis, and alkalosis on canine defibrillation.

Our purpose was to assess the effect of myocardial ischemia, left ventricular hypertrophy, and systemic hypoxia and acid-base abnormalities on the energy requirements for defibrillation. We determined the defibrillation threshold (DFT), the minimum energy required to defibrillate. DFT was not significantly elevated after left anterior descending coronary occlusion, nor was there a relationship between the size of the occluded coronary distribution area (coronary risk area) and the change in DFT in individual animals. Renal hypertension and left ventricular hypertrophy were induced by unilateral nephrectomy and contralateral renal artery stenosis. DFT in left ventricular hypertrophy dogs was not significantly higher than in dogs without hypertrophy. Finally, we induced systemic hypoxia and acid-base abnormalities. Neither respiratory nor metabolic acid-base disturbances affected DFT, but during systemic hypoxia (O2 tension 45 +/- 2) DFT fell from 83 +/- 49 to 58 +/- 28 J (P less than 0.01). Thus in dogs, myocardial ischemia, left ventricular hypertrophy, and acid-base abnormalities do not elevate defibrillation energy requirements, whereas hypoxia reduces the energy needed to defibrillate.

Acidosis↗
PubMed1982

Transient renal artery stenosis produced by a pheochromocytoma.

A hypertensive young woman was referred for renal artery angioplasty with the radiographic finding of a right renal artery stenosis and elevated right renal vein plasma renin activity. A repeat preangioplasty arteriogram, obtained six weeks after the institution of antihypertensive therapy that included a vasodilator, demonstrated a diminished right renal artery stenosis and showed a right adrenal pheochromocytoma that was removed surgically. After surgery both the right renal artery caliber and the blood pressure returned to normal. Knowledge of this unusual association between pheochromocytoma and renovascular hypertension could prevent ineffective and unnecessary renal artery angioplasty and/or surgery.

Adrenal Gland Neoplasms↗
PubMed1981

Elective cardioversion: influence of paddle-electrode location and size on success rates and energy requirements.

We compared the success rates and energy requirements of two electrode-paddle positions (anteroposterior vs. anterolateral) and different paddle sizes in the elective cardioversion of atrial arrhythmias. We prospectively studied 173 patients - 111 in atrial fibrillation and 62 in atrial flutter. The anterolateral paddles used were either two standard-size (8.5-cm diameter) paddles or one 13-cm diameter anterior paddle with one standard-size lateral paddle. The anteroposterior paddles used were either a standard-size or a 13-cm anterior paddle with 12-cm posterior paddle. Overall cardioversion success rates with either paddle position were similar (greater than 90 per cent). The larger paddles did not significantly reduce energy requirements for cardioversion of either arrhythmia. We conclude that anterolateral paddles are as effective as anteroposterior paddles for the elective cardioversion of atrial arrhythmias, and that there is no demonstrable advantage to using paddles that are larger than the standard size in either position.

Adult↗
PubMed1980

Partial regressive occipital vertebra.

Craniocervical developmental anomalies can be quite varied and many involve the proatlas and its remnants. A previously undescribed variant consisting of a remnant of the proatlas and its transverse processes is reported and the developmental anatomy of this region is summarized.

Adult↗
PubMed1979

Wire localization of nonpalpable breast lesions.

The authors describe a method of localizing nonpalpable breast lesions using a needle and wire. It allows accurate localization without worrying about shifting of the wire before or during biopsy.

Breast Neoplasms↗
PubMedDate not supplied

Iridoid glucosides from Phlomis tuberosa L. and Phlomis herba-ventis L.

A new iridoid glucoside, 5-desoxysesamoside, was isolated from Phlomis tuberosa L. (Lamiaceae) together with three known iridoid glucosides sesamoside, shanziside methyl ester and lamalbid. Lamiide was found in P. herba-ventis ssp. pungens in high concentrations.

Glucosides↗