Kjell Ivarsson

Feedback interstitial diode laser (805 nm) thermotherapy system: Ex vivo evaluation and mathematical modeling with one and four-fibers

In this study a newly developed microprocessor controlled power regulation and thermometry system integrated with a diode laser (805 nm wavelength) was evaluated with respect to temperature distribution, effectiveness of regulation, and ability to predict temperature distributions by computer simulation.

Interstitial laser thermotherapy (ILT) of breast cancer

AIM To find out if ILT can be used as radical treatment of breast cancer. METHOD Twenty-four patients, aged 39-84 (mean 61), with invasive breast cancer were treated with ILT. All underwent mammography, ultrasound and core biopsy before treatment. The tumour was an invasive ductal carcinoma in 15 patients, a lobular carcinoma in eight and lobular-ductal cancer in one. Average tumour diameter was 14 mm on ultrasound (5-35). Patients were treated in the outpatient clinics under local anaesthesia. Probes were placed under ultrasound guidance, in 19 patients, and ILT was performed with a diode laser at a steady-state temperature of 48 degrees C for 30 min using temperature feedback control. Standard surgical excision was performed 12 (4-23) days after ILT and was preceded by Doppler ultrasound. RESULTS Treatment-induced necrosis of invasive cancer was 33% (range 0-100) and was complete in three patients. At follow-up before surgery, the extent of laser damage could not be judged with ultrasound, although abolished tumour blood flow was demonstrated after treatment resulting in large necroses. Efficacy of treatment varied negatively with tumour size. The inefficacy of ILT was mainly due to the underestimation of tumour size by mammography and ultrasound and the shortcomings of these methods to demonstrate tumour borders, tumour irregularity and carcinoma in situ (CIS). ILT was well tolerated. Five patients had breast tenderness, and three patients had pain, during the first day after treatment. Small skin necroses were observed in two patients. CONCLUSION Small breast cancers can be treated radically with ILT. The method may become useful in the treatment of breast cancer but needs further refinement, even for small well-defined breast cancers, if it is going to be employed for radical treatment.

Comparison between interstitial laser thermotherapy and excision of an adenocarcinoma transplanted into rat liver.

The aim of this study was to compare interstitial laser thermotherapy with excision of a liver tumour. A dimethylhydrazine-induced adenocarcinoma was transplanted (implanted if not stated otherwise) into the left lateral lobe of the rat liver, and treatment was performed 8 days later. In the main experiment, rats were treated with resection of the tumour-bearing lobe or underwent interstitial laser thermotherapy, which was performed at a steady-state temperature of 46 degrees C for 30 min, 3 mm from the tumour margin. The incidence and extent of intraperitoneal spread was smaller after laser thermotherapy than after resection of the tumour-bearing lobe, with no difference in local control. Metastatic spread after resection of the median liver lobe was similar to that observed after sham procedures for thermotherapy or resection, suggesting that the advantage of thermotherapy was not due to a difference in surgical trauma. Additional studies showed that laser thermotherapy reduced intraperitoneal spread when treatment was suboptimal or in a tumour inoculation model and suggested that immunological mechanisms might be involved. It is concluded that interstitial laser thermotherapy reduces spread of liver tumour compared with resection.

Resistance to tumour challenge after tumour laser thermotherapy is associated with a cellular immune response.

Previous studies in our laboratory have shown that interstitial laser thermotherapy (ILT) of an experimental liver tumour is superior to surgical excision, at least partly due to a laser-induced immunological effect. The aim of the present study was to investigate the time–response relationship of the ILT-induced immunisation and the cellular response of macrophages and lymphocytes. A dimethylhydrazine-induced adenocarcinoma was transplanted into the liver of syngeneic rats. Rats with tumour were treated 6–8 days later (tumour size 0.25–0.40 cm3) with ILT of tumour or resection of the tumour-bearing lobe. Two groups of rats without tumour were treated with resection of a normal liver lobe or ILT of normal liver. A challenging tumour was implanted into the liver of each rat 2, 5 or 10 weeks after primary treatment. Rats were killed 6, 12 and 48 days (or earlier due to their condition) after challenge (n=8 in all groups). Immunohistochemical techniques were used to determine lymphocytes (CD8, CD4) and macrophages (ED1, ED2) in rats having had treatment of a primary tumour. Interstitial laser thermotherapy of the first tumour was followed by eradication of challenging tumour and absence of tumour spread. This contrasted with rapid growth and spread of challenging tumour in the other groups. In the challenging vital tumour tissue and in the interface between the tumour and surroundings, the number of ED1 macrophages and CD8 lymphocytes was higher in rats having been treated with the ILT of tumour than in those having undergone resection of the tumour-bearing lobe. The number of ED2 macrophages and CD4 lymphocytes was low and did not vary between these two groups. Interstitial laser thermotherapy elicited an immune response that eradicated a challenging tumour and was associated with increased numbers of tumour-infiltrating macrophages and CD8 lymphocytes.

Changes in Local Hepatic Blood Perfusion During Interstitial Laser-Induced Thermotherapy of Normal Rat Liver Measured by Interstitial Laser Doppler Flowmetry

Abstract. Interstitial laser Doppler flowmetry was used to measure the effect of interstitial laser-induced thermotherapy on local blood perfusion in normal rat liver in the peripheral treatment region elevated to hyperthermic temperatures. The Nd:YAG laser emitting at 1064 nm was utilised as heat generation source. The plane-cut tip of an optical fibre was placed in the middle of the exteriorised left liver lobe. Blood perfusion and temperature were measured in the liver parenchyma 4 mm from the laser fibre. The temperature at the location of the liver temperature sensor was maintained at 41 or 44°C during 30 min by regulating the power of the heating laser. The laser Doppler signal was recorded during and after heat treatment, for a total time of 60 min. At 41°C, a significant increase in perfusion up to 1.3 times the initial value was observed 2–16 min after start of treatment. At 44°C, perfusion decreased continuously during and after treatment, and was significantly different from control 40 min after start of treatment. The results may be valuable in assessing the thermal response of tissues surrounding the target in interstitial laser-induced thermotherapy of liver tumours during conditions of normal blood flow.

The probability of patients being admitted from the emergency department is negatively correlated to in-hospital bed occupancy – a registry study

BackgroundThe association between emergency department (ED) overcrowding and poor patient outcomes is well described, with recent work suggesting that the phenomenon causes delays in time-sensitive interventions, such as resuscitation. Even though most researchers agree on the fact that admitted patients boarding in the ED is a major contributing factor to ED overcrowding, little work explicitly addresses whether in-hospital occupancy is associated to the probability of patients being admitted from the ED. The objective of the present study is to investigate whether such an association exists.MethodsRetrospective analysis of data on all ED visits to Helsingborg General Hospital in southern Sweden between January 1, 2011, and December 31, 2012, was undertaken. The fraction of admitted patients was calculated separately for strata of in-hospital occupancy <95%, 95–100%, 100–105%, and >105%. Multivariate models were constructed in an attempt to take confounding factors, e.g., presenting complaints, age, referral status, triage priority, and sex into account. Subgroup analysis was performed for each specialty unit within the ED.ResultsOverall, 118,668 visits were included. The total admitted fraction was 30.9%. For levels of in-hospital occupancy <95%, 95–100%, 100–105%, and >105% the admitted fractions were 31.5%, 30.9%, 29.9%, and 28.7%, respectively. After taking confounding factors into account, the odds ratio for admission were 0.88 (CI 0.84–0.93, P >0.001) for occupancy level 95–100%, 0.82 (CI 0.78–0.87, P >0.001) for occupancy level 100–105%, and 0.74 (CI 0.67–0.81, P >0.001) for occupancy level >105%, relative to the odds ratio for admission at occupancy level <95%. A similar pattern was observed upon subgroup analysis.ConclusionsIn-hospital occupancy was significantly associated with a decreased odds ratio for admission in the study population. One interpretation is that patients who would benefit from inpatient care instead received suboptimal care in outpatient settings at times of high in-hospital occupancy. A second interpretation is that physicians admit patients who could be managed safely in the outpatient setting, in times of good in-hospital bed availability. Physicians thereby expose patients to healthcare-associated infections and other hazards, in addition to consuming resources better needed by others.

Associations between in-hospital bed occupancy and unplanned 72-h revisits to the emergency department: a register study.

BackgroundA possible downstream effect of high in-hospital bed occupancy is that patients in the emergency department (ED) who would benefit from in-hospital care are denied admission. The present study aimed at evaluating this hypothesis through investigating associations between in-hospital bed occupancy at the time of presentation in the ED and the probability for unplanned 72-hour (72-h) revisits to the ED among patients discharged at index. A second outcome was unplanned 72-h revisits resulting in admission.MethodsAll visits to the ED of a 420-bed emergency hospital in southern Sweden between 1 January 2011 and 31 December 2012, which did not result in admission, death, or transfer to another hospital were included. Revisiting fractions were computed for in-hospital occupancy intervals <85%, 85% to 90%, 90% to 95%, 95% to 100%, 100% to 105%, and ≥105%. Multivariate models were constructed in an attempt to take confounding factors from, e.g., presenting complaints, age, referral status, and triage priority into account.ResultsIncluded in the study are 81,878 visits. The fraction of unplanned 72-h revisits/unplanned 72-h revisits resulting in admission was 5.8%/1.4% overall, 6.2%/1.4% for occupancy <85%, 6.4%/1.5% for occupancy 85% to 90%, 5.8%/1.4% for occupancy 90% to 95%, 6.0%/1.6% for occupancy 95% to 100%, 5.4%/1.6% for occupancy 100% to 105%, and 4.9%/1.4% for occupancy ≥105%.In the multivariate models, a trend to lower probability of unplanned 72-h revisits was observed at occupancy ≥105% compared to occupancy <95% (OR 0.88, CI 0.76 to 1.01). No significant associations between in-hospital occupancy at index and the probability of making unplanned 72-h revisits resulting in admission were observed.ConclusionsThe lack of associations between in-hospital occupancy and unplanned 72-h revisits does not support the hypothesis that ED patients are inappropriately discharged when in-hospital beds are scarce. The results are reassuring as they indicate that physicians are able to make good decisions, also while resources are constrained.

Interstitial laser thermotherapy of a rat liver tumour: Effect of hepatic inflow occlusion

Interstitial laser thermotherapy was used to treat rat liver tumours. The aim was to investigate the influence of temperature and temporary hepatic inflow occlusion on tumour growth and blood perfusion.

Acute abdominal pain; prehospital evaluation of Ketobemidone administration

Abdominal pain is a frequent condition among patients in ambulance care and, each patient should receive optimal doses for pain relief. The aim of this study was to evaluate pain scores at admission to hospital and relationship to age, in pre-hospital patients with treated acute abdominal pain. Pain was scored with a Numeric Rating Scale (NRS) by each patient at the rescue scene (NRSs). Ketobemidone was then administered intravenously in incremental doses to achieve NRS-values of four or less, and then NRS was re-evaluated at admission to hospital (NRSh). The results from 64 patients demonstrated statistical significant differences between median NRSs and NRSh scores; 7.0 and 3.5 respectively (p<0.05). Mean ketobedmidone doses were 3.7±1.9 mg. There was a negative correlation between age and pain scores (p<0.01), and NRSs correlated with NRSh which means that patients with high scores for initial pain also scored higher on arrival in the emergency room (p<0.05). This study describes that the general dose of pain-relieving medications with ketobemidone seems to be adequate since the patientssubjective assessments of pain achieve a NRS value less than four at admission to hospital. The study also demonstrate that older the patients, less pain was reported both on the rescue scene and on admission at the hospital.

Attending physicians believe that hospitalized patients are treated at the appropriate level of care: A qualitative study

Abstract The purpose of this paper is to investigate the appropriateness of hospitalized patients’ level of care as assessed by their treating physicians. The study was conducted as a qualitative study, based on a questionnaire. The study suggests that physicians generally believe that patients who occupy in-hospital beds are cared for at the appropriate level of care. It is worth to note that a relatively large fraction of patients have had their medical needs attended to, but remain hospitalized while waiting for municipal action. Successful downsizing of in-hospital bed-capacity assumes that either a segment of patients who are inappropriately hospitalized exists and could be identified, or that viable alternatives to in-hospital care exist and are available. The results of the present study argue against the first statement. However, we have identified a segment of patients who experience an unnecessarily long in-patient length of stay due to waiting times for municipal action and other post-discharge follow-up measures. Alternatives to in-hospital care which deserve further attention are supporting services in the outpatient setting.