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Biomedical subjects

P Halvorsen

Publications and source records attributed to P Halvorsen.

10 recordsLinked to original sources
PubMed1997

An accurate method for localization of the boost volume in breast radiotherapy.

Patients with early stage breast cancer who are treated with adjuvant radiotherapy post-lumpectomy often receive a tumor bed boost with electrons. The tissue considered at high risk of local recurrence is defined from the surgical scar to the deepest portion of the tumor bed, which is ideally marked with radiopaque surgical clips. To adequately treat this tissue, one must superimpose the scar, surgical path and clips within the beam and choose an appropriate electron energy based on the deepest clip depth, while sparing low risk and cosmetically important tissues. Clip localization is therefore emphasized in the literature; however, published procedures do not adequately address how to meet all of the above goals. Additionally, CT planning alone cannot assess optimal coverage of tissue outside of the transverse plane, nor guarantee visualization of all clips. We have devised a method of boost planning based on localization of the surgical clips which may be accomplished in a single simulation session, utilizing two sets of orthogonal films, radiopaque skin surface markers, and FSD readings. Our procedure meets all of the above goals, is applicable to any field orientation that can be simulated, and can provide useful information for alternative techniques.

Breast Neoplasms↗
PubMed1997

Post-operative epidural analgesia with low dose fentanyl, adrenaline and bupivacaine in children after major orthopaedic surgery. A prospective evaluation of efficacy and side effects.

The efficacy and side effects of 100 lumbar epidural treatments with low concentrations of bupivacaine (1 mg mL-1), fentanyl (2 micrograms mL-1) and adrenaline (2 micrograms mL-1) combined with rectal paracetamol were prospectively evaluated in children aged 4-14 years after femoral osteotomy. The mean treatment time was 43 h and the mean dose was 0.18 mL kg-1 h-1. Ninety-nine per cent of the children were either without pain or experienced very low pain at rest for at least 80% of the treatment time. The same was the case in 80% of children when pain evaluation was made on active movement. No cases of seizures, signs of catheter migration, hypotension or respiratory depression were observed. Sixty-three per cent of the patients experienced nausea or vomiting, but antiemetic treatment was indicated in only 11%. One epidural treatment had to be stopped in a child who did not respond to antiemetics. The incidence of pruritus was high (49%), but the symptoms were mild and limited.

Adolescent↗
PubMed1996

[Accidental administration of 50 mg racemic adrenaline to a 2-year-old boy].

A two-year-old boy received by mistake 50 mg racemic adrenaline intravenously, corresponding to 1.8 mg kg-1 of L-adrenaline. Blood pressure increased to 160/105 mm Hg, heart rate to 160 beats min-1 and pulmonary oedema developed over the next two hours. He was treated with nitroprusside, nitroglycerine and digitoxin, and was intubated and ventilated. After three hours a hypotensive phase occurred, probably due to down-regulation of the beta- and alpha-adrenoceptors. This recessitated infusions of very high concentrations of catecholamines for 72 hours. Renal failure recessitated renal transplantation, after which the child made an uneventful recovery.

Acute Kidney Injury↗
PubMed1995

[Malignant hyperthermia--still a current and dangerous problem].

Malignant hyperthermia is a potentially fatal condition inducible by volatile anaesthetics and/or suxamethonium in genetically susceptible individuals. A disturbed calcium homeostasis in skeletal muscle (possibly in the ryanodin receptor) results in elevated myoplasmatic calcium. The latter causes muscle contraction and a hypermetabolic state, clinically observed as rigidity, fever, hypercarbia, metabolic acidosis and hyperkalemia. Arythmia ensues. Dantrolene inhibits the release of calcium and can halt the process if the diagnosis is made early. A fatal incident of probable malignant hyperthermia in a 13 year old boy is described and evaluated according to a multifactorial clinical grading scale. The value of the in vitro contracture test to diagnose malignant hyperthermia is discussed. Suggestions concerning the treatment of masseterspasm rigidity, an acute episode of malignant hyperthermia, and safe anaesthesia for susceptible patients are presented.

Adolescent↗
PubMed1995

Accidental intravenous administration of 50 mg of racemic adrenaline in a 2-year-old boy.

A 2-year-old boy received, by mistake, 50 mg racemic adrenaline intravenously, equivalent to 1.8 mg kg-1 of L-adrenaline. The blood pressure increased to 160/105 mmHg, the heart rate to 160 beats min-1, and pulmonary oedema developed over the next 2 h. He was treated with nitroprusside, nitroglycerin and digitoxin, and was intubated and ventilated. After 3 h a hypotensive phase occurred which required infusions of very high concentrations of catecholamines for 72 h. Renal failure required renal transplantation after which the child made an uneventful recovery.

Acute Kidney Injury↗
PubMed1990

[Acute pulmonary dysfunction in adults. Adult respiratory distress syndrome--ARDS].

During a 3-year period 0.1% of all patients undergoing surgery and 0.3% of the patients submitted for trauma developed ARDS. The diagnosis was based on strict criteria. Mortality among the 42 patients was 45.2%. Abdominal sepsis was associated with high mortality, trauma with a much better prognosis. Swan-Ganz catheters were used in 81% of the patients. The measurements were characterized by high pulmonary vascular resistance and increased intrapulmonary shunting. However, the initial recordings showed only small differences between survivors and fatal cases as regards haemodynamics and blood gas parameters. Mortality was associated with low diuresis, heart failure, need of inotropic support and on age of over 50 years. The significance of invasive central monitoring is discussed.

Adult↗
PubMed1983

Biparietal diameter in premature rupture of membranes: errors in estimating gestational age.

Experience on our clinical service suggested that the real-time ultrasonically measured fetal biparietal diameter (BPD) might not accurately estimate gestational age in the preterm pregnancy complicated by premature rupture of membranes (PROM). Of 2510 consecutive pregnancies for which the BPD could be obtained on ultrasound examination at or beyond 26 weeks gestation, 122 were complicated by PROM. For pregnancies with and without PROM, the relationship, if any, between BPD and gestational age at the time of examination was determined by regression analysis and the resulting equations compared by F test. The regression equations were found to be significantly different (F = 17.2, P less than 0.01); the BPD was found to underestimate the true gestational age in the presence of PROM. To model the situation in which the pregnancy is recognizably very premature, the BPD/gestational age relationship was evaluated at less than or equal to 30 weeks. In these pregnancies the correlation of gestational age with BPD was not statistically significant in the presence of PROM. These results indicate that in the presence of PROM, the BPD may not be a reliable estimator of the gestational age of the fetus. In the presence of PROM, gestational age dependent management decisions would be better based on clinical and ultrasound criteria rather than the ultrasonically determined BPD.

Birth Weight↗
PubMedDate not supplied

Placebo-controlled comparison of single intramuscular doses of ketorolac tromethamine and pethidine for post-operative analgesia.

The analgesic efficacy and safety of single doses of 10 mg and 30 mg ketorolac tromethamine and 100 mg pethidine were evaluated in a double-blind, parallel-group study. The drugs were administered intramuscularly to patients experiencing moderate, severe or very severe pain immediately following major abdominal surgery. A total of 129 patients were randomly assigned to receive either active drug (n = 32 for each treatment group) or placebo (n = 33), and the patients assessed pain intensity and pain relief on a visual analogue scale at regular intervals over the following 8 h. During the first 2 h, pethidine had a more rapid onset of action than ketorolac or placebo, and thereafter 100 mg pethidine and 30 mg ketorolac were equally effective. Ketorolac, at a dose of 10 or 30 mg, and 100 mg pethidine were clinically and statistically more effective than placebo, with 30 mg ketorolac having a similar efficacy to 100 mg pethidine over the 8-h study period and 10 mg ketorolac being slightly less effective than 30 mg ketorolac. No serious adverse events were reported.

Abdomen↗