An observational post-authorization safety study (PASS) of naloxegol drug utilization in four European countries

PURPOSE

Naloxegol has been shown to be an efficient alternative to treat opioid-induced constipation (OIC). This study aimed at describing the characteristics of naloxegol users and assessing patterns of naloxegol use and associated factors.

METHODS

This drug utilization cohort study used observational registry data on patients newly prescribed naloxegol in four European countries. Patient characteristics and patterns of naloxegol use and associated factors were described.

RESULTS

A total of 17 254 naloxegol users were identified across the countries. Their median age was 56-71 years, and each country had a majority of women (ranging 57.5%-62.9%). Multiple comorbidities, including cancer, were common. Natural opium alkaloids and osmotically acting laxatives (excluding saline) were the most frequently used opioids and laxatives. Overall prior use of opioids ranged from 91.9% to 99.6% and overall prior use of laxatives ranged from 69.9% to 92.4%. Up to 77.7% had prior use of medications with interaction potential, and up to 44.5% used them concurrently with naloxegol. Naloxegol was discontinued by 55.1%-90.9% of users, typically during the first 30 days. Approximately 10%-30% switched to or augmented the treatment with another constipation medication or restarted naloxegol after discontinuation. Augmentation with another constipation medication was relatively common, suggesting that naloxegol was used for multifactorial constipation.

CONCLUSION

The present study reflects real-world clinical use of naloxegol, including in vulnerable patient groups. Some naloxegol users lacked laxative or regular opioid use within six months before index date or used naloxegol concomitantly with medications presenting an interaction potential.

Home administration of needle injections for children with rheumatic diseases: A qualitative study on nurses' perception of their educational role

PURPOSE

To explore nurses' perceptions of their educational role, pedagogical competence, and practice in teaching children with rheumatic diseases and their parents to manage subcutaneous injections at home.

DESIGN AND METHODS

In this qualitative study, we used thematic analysis to analyze data from three focus groups with 14 nurses responsible for patient education at one pediatric ward and two outpatient clinics.

RESULTS

We identified three main themes capturing nurses' perceptions of their educational role: myriad expectations, awareness of own competence, and facilitation and prioritization of patient education. Nurses perceived patient education as an expected but challenging duty of their work. They described a lack of pedagogical competence, insecurity in managing parents' and children's fears and worries, and limited organizational structures guiding their educational role. Nurses who worked in outpatient clinics felt freer to individualize education compared to ward nurses.

CONCLUSIONS

Nurses perceive their educational role as significant in enabling children and parents to manage subcutaneous injections at home; however, they require pedagogical competence integrated with daily practice to provide high-quality care. Short-term admissions require a different organization of patient education than before.

PRACTICAL IMPLICATIONS

Nurses need increased training in communication and management of children's pain and fear during needle injections. Competence development should include opportunities for reflection and guidance in clinical practice. Pediatric specialist nurses at outpatient clinics seem to have better competence to provide individual patient education for these families. The potential advantage of web-based solutions for nurses' patient education is a promising avenue for future research.

Responses after spinal interventions in a clinical pain practice - a pragmatic observational study

Introduction There is limited evidence for effect of interventional treatment, and pragmatic studies are needed to assess these interventions within a clinical setting. The aim of this study was to describe patients referred to an interventional pain clinic and investigate responses after spinal intervention in general and for radiofrequency ablation (RFA) and transforaminal epidural corticosteroid administration (TECA), specifically. Methods This is a prospective, non-controlled study of patients with chronic spinal pain. The procedures were performed in accordance with the Spine Intervention Society recommendations. Outcome data after a median of 4.5 months are presented, and for those treated with RFA also after 6 and 12 months. Results Among 815 patients, 190 patients underwent diagnostic blocks only and 625 interventional treatment, of these 94 RFA and 246 TECA. Of the whole sample 70% reported pain reduction, for 49% ≥ 50%, while 9% were pain free (p < 0.001). Highest pain intensity decreased from 7.1 to 5.4 [95% Confidence Interval of the Difference (95%-CI): 1.4-1.9] (p < 0.001), while Euroqual - visual analogue scale for general health (EQ-VAS) improved from 48 to 58 (95%-CI: 7.6-11.9) (p < 0.001), and Euroqual-5 Dimensions-5 Levels Index for health related quality of life (EQ-5D-5L Index) from 0.489 to 0.628 (95%-CI: 0.123-0.157) (p < 0.001). The proportions, not taking analgesics, increased from 16% to 30%, and proportion taking strong opioids decreased from 14% to 9% (p < 0.001). We found no significant change in proportion receiving physiotherapy/other treatment nor occupational status. No complications were reported. Among patients treated with RFA, 77% reported pain reduction, for 56% ≥ 50%, while 9% were pain free (p < 0.001). Highest pain intensity decreased from 6.9 to 4.6 (95%-CI: 1.6-3.0) (p < 0.001), while EQ-VAS improved from 47 to 57 (95%-CI: 4.8-13.6 (p < 0.001), and EQ-5D-5L Index from 0.489 to 0.643 (95%-CI: 0.117-0.191) (p < 0.001). The proportion not taking analgesics, increased from 7% to 23% and proportion taking strong opioids decreased from 16% to 10%. Among patients who responded at 6- and 12-month follow up, the proportions reporting pain reduction, EQ-VAS, and EQ-5D-5L Index remained significantly improved from baseline, and the change in proportions taking analgesic and opioids achieved statistical significance. We found no significant change in proportion receiving physiotherapy/other treatment nor occupational status. Among patients treated with TECA, 58% reported pain reduction, for 36% ≥ 50%, while 5% were pain free (p < 0.001). Highest pain intensity decreased from 7.2 to 6.2 (95%-CI 0.5-1.4) (p < 0.001), while EQ-VAS improved from 46 to 52 (95%-CI: 2.0-3.6) (p < 0.001), and EQ-5D-5L Index from 0.456 to 0.571 (95%-CI: 0.077-0.138) (p < 0.001). The proportions, not taking analgesics, increased from 17% to 27% and proportion taking strong opioids decreased from 15% to 10%, but the changes did not reach statistical significance. We found no significant changes in the proportion who recieved physiotherapy/other treatment nor occupational status. Conclusion The study demonstrates substantial short-term responses after spinal intervention and long-lasting improvement for a subsample of the RFA treated patients. We observed larger proportions reporting pain reduction among those treated with cervical RFA. Implementation Quality assessment should be implemented in interventional pain clinics to improve treatment quality.

The efficacy of botulinum toxin A treatment for tension-type or cervicogenic headache: a systematic review and meta-analysis of randomized, placebo-controlled trials

OBJECTIVES

The pathogeneses of chronic tension-type headache (CTTH) and cervicogenic headache (CEH) are not well established. Peripheral activation or sensitization of myofascial nociceptors is suggested as a potential mechanism and injections of botulinum toxin (BONTA) have thus been used in the treatment for both headache conditions. BONTA inhibits the release of acetylcholine at the neuromuscular junction and inhibits contraction of skeletal muscles. If the pain is precipitated by increased tone in cervical muscles, local injections of BONTA could represent a prophylactic measure. However, the treatment is still controversial, and a thorough assessment of the current evidence is required. This review aims to assess the evidence of BONTA injection as a prophylactic treatment for CTTH and CEH by reviewing and examining the quality of placebo-controlled, randomized trials.

METHODS

Data sources: we searched in the following databases: PubMed (including Medline), Embase, Cochrane Central register of Controlled Trials, Cinahl, Amed, SCOPUS and Google Scholar including other repository sources. Both MeSH and free keywords were used in conducting the systematic search in the databases. The search covered publications from the root of the databases to November 2020.

STUDY ELIGIBILITY CRITERIA

The review included RCTs, comparing single treatment of BONTA with placebo on patients with CTTH or CEH above 18 years of age, by measuring pain severity/relief or headache frequency.

DATA EXTRACTION

The following data were extracted: year of publication, country, setting, trial design, number of participants, injection procedure, BONTA dosages, and clinical outcome measures.

STUDY APPRAISAL

To assess validity and quality, and risk of bias, the Oxford Pain Validity Scale, Modified Jadad Scale, last version of Cochrane Collaboration's tool for assessing risk of bias (RoB 2), and the CONSORT 2010 Checklist were used. The trials were assessed, and quality scored independently by two of the reviewers. A quantitative synthesis and meta-analyses of headache frequency and intensity were performed.

RESULTS

We extracted 16 trials, 12 on prophylactic BONTA treatment for CTTH and four on CEH. Of these 12 trials (8 on CTTH and 4 on CEH) were included in the quantitative synthesis. A majority of the trials found no significant difference on the primary outcome measure when BONTA treatment was compared with placebo. Three "positive" trials, reporting significant difference in favor of BONTA treatment, but two of these were hampered by low validity and quality scores and high risk of bias.

CONCLUSIONS

There is no clear clinical evidence supporting prophylactic treatment with BONTA for CTTH or CEH.

Postoperative opioids and risk of respiratory depression - A cross-sectional evaluation of routines for administration and monitoring in a tertiary hospital

OBJECTIVES

Opioids are the most potent analgesics in the treatment of postoperative pain. Respiratory depression is, however, a serious side effect. The aims of this study were to evaluate current practice and routines for post-operative administration of opioids in a Norwegian university hospital and to evaluate whether the clinical safeguards adequately protected patients' safety regarding risk of respiratory depression.

METHODS

The study had a retrospective cross-sectional design and included 200 patients, treated with opioids postoperatively. The patients were treated in a post-anesthesia care unit (PACU) before transferal to a surgical ward. Relevant data such as opioid dosages, routes of administration, sedation and respiratory function, routines for patient monitoring, and numbers of patients with opioid induced respiratory depression was collected.

RESULTS

Two patients (1%) developed respiratory depression that needed naloxone to reverse the effect, and 32 patients (16%) had a respiratory rate (RR) <10/min, which may have been caused by opioids. In the PACU, the patient's RR was evaluated on a routine base, but after transferal to a surgical ward RR documented in only 7% of the patients.

CONCLUSIONS

The lack of routines for patient monitoring, especially RR, represented a risk of not detecting opioid induced respiratory depression.

I don't want to think about it: a qualitative study of children (6-18 years) with rheumatic diseases and parents' experiences with regular needle injections at home

BACKGROUND

Overall outcomes of pediatric rheumatic diseases (RD) have improved due to treatment with biologic agents and methotrexate. For many children, this treatment often entails regular needle injections. Pain and fear of needle injections are common in childhood, but how children and parents handle long-term needle injections at home has not been fully explored. This study aimed to explore how regular needle injections affect children with RD and their parents in their daily living.

METHODS

This explorative qualitative study used individual interviews and focus groups to ensure a comprehensive investigation of the topic. Children aged 6 to 16 years (n = 7) and their parents (n = 8) were interviewed individually 4 to 6 months after the onset of needle injection treatment. The focus groups included children aged 11 to 17 years (n = 9) and parents (n = 8) with a minimum of 6 months of experience with injection treatment. Data were analyzed using thematic analysis.

RESULTS

The main themes; "challenges," "motivational factors," and "routines" captured experiences and strategies that influenced the continuation of needle injections at home. Many children feared the moment immediately before the needle stick, although they had become accustomed to the pain. Most parents felt insecure about handling needle injections and lacked follow-up from healthcare providers. The children's experience of treatment effects and self-confidence were essential to maintain motivation for further injections. A number of coping strategies helped children focus away from injection related discomfort, often discovered by chance. Facilitating firm routines and shared responsibility within families helped children develop self-confidence during the procedure. Children and parents struggled to find suitable information on the Internet.

CONCLUSIONS

Children and parents experienced long-term needle injections challenging. They used their own limited resources and cooperated within the families to create routines and to introduce coping strategies necessary to manage and keep up with the procedure. Although the injection itself was not experienced very painful, the discomfort, worries and impact on daily life represented far more than a little needle stick, and thus needs more attention from healthcare providers.

Cryoneurolysis for cervicogenic headache - a double blinded randomized controlled study

Background and aims Cervicogenic headache (CEH) is a debilitating condition and analgesics have limited effect. Percutaneous cryoneurolysis is thus still in use although the clinical evidence is lacking. We present a randomized, controlled study to assess the clinical efficacy of cryoneurolysis compared with a corticosteroid combined with a local anaesthetic. Methods In a university-based outpatient pain clinic we performed a randomized, double blinded, comparative study with an 18-week follow-up. After positive diagnostic test blocks 52 eligible patients were randomly allocated in a ratio of 3:2, 31 participants to occipital cryoneurolysis and 21 participants to injections of 1 mL methylprednisolone 40 mg/mL (Depo-Medrol®) combined with 1 mL bupivacaine 5 mg/mL. Results We observed a significant pain reduction of more than 50% in both treatment groups, slightly improved neck function and reduced number of opioid consumers. After 6-7-weeks, however, pain intensity increased gradually, but did not reach baseline within 18 weeks. Although cryoneurolysis provided a more prolonged effect, the group differences did not reach statistical significance. Health related quality of life and psychological distress improved minimally. A large number reported minor and transient side effects, but we found no significant group differences. After 18 weeks, 29% rated the headache as much improved, and 12 (24%) somewhat improved, but a large proportion (78%) reported need for further intervention/treatment. Conclusions Cryoneurolysis provided substantial, but temporary pain relief, and the effect was not significantly different from injections of a corticosteroid combined with a local anaesthetic. Participants were selected by a single test block, and the neurolytic procedure was guided by anatomical landmarks and nerve stimulation. A stricter patient selection and an ultrasound-guided technique might have improved the results. Cryoneurolysis provides temporary pain relief not significantly superior to corticosteroid injection, and the results question the value of occipital cryoneurolysis for a chronic pain condition like CEH. Implications Occipital cryoneurolysis may be considered when non-invasive treatments appear insufficient, but only for patients who have responded substantially to test blocks. A risk of local scar and neuroma formation by repeated cryoneurolysis, leading to neuropathic pain has been discussed by other researchers.

Mediators of Pain and Physical Function in Female and Male Patients with Chronic Pain

Purpose

Chronic pain is often multifactorial and accompanied by psychological distress, catastrophizing thoughts, reduced physical function, and socio-economic worries. In this explorative study, we investigated potential mediators in the relationships of psychological and demographic variables with chronic pain and physical function in women and men.

Patients and Methods

The study included 301 patients admitted to a multidisciplinary pain clinic. Prior to their first consultation, patients completed a questionnaire including items on demographics (age, education, occupational and financial situation), catastrophizing thoughts, psychological distress, pain intensity, and physical function. Hierarchical multiple regression analyses examined demographic and psychological factors associated with pain intensity and physical function. Mediation and reversed mediation models were tested and developed based on calculated relations in the regression analyses between demographic, psychological, pain intensity and physical function variables.

Results

Fifty-eight percent were females and mean age 43.8 and 46.0 years for women and men, respectively. In the regression analyses, psychological factors accounted better for pain intensity than demographic variables, while physical function was best accounted for by demographic variables. Among women, catastrophizing thoughts mediated significantly the relationships between education and pain intensity, and between education and physical function. Psychological distress mediated significantly the relationships between financial situation and pain intensity, and between financial situation and physical function in women. In men, the only significant mediation model was psychological distress mediating the relationship between financial situation and pain intensity. Some of the reversed models revealed indirect effects, indicating bidirectionality.

Conclusion

The results indicate that there might be gender-specific mediators in how demographic variables are associated with pain intensity and physical function. This suggests an awareness among clinicians of potential gender-specific factors mediating pain problems, and the need for a gender-specific, multidisciplinary approach in the treatment of chronic pain.

Children's fear of needle injections: a qualitative study of training sessions for children with rheumatic diseases before home administration

BACKGROUND

Treatment of rheumatic diseases in children often includes long-term needle injections, which represent a risk for refusing medication based on potential needle-fear. How nurses manage children's fear and pain during the initial educational training session of subcutaneous injections, may affect the management of the subsequent injections in the home settings. The aim of this study was to explore how children expressed fear and pain during these training sessions, and how adults' communication affected children's expressed emotions.

METHODS

This qualitative explorative study used video observations and short interviews during training sessions in a rheumatic hospital ward. Participants were children between five and fifteen years (n = 8), their parents (n = 11) and nurses (n = 7) in nine training sessions in total. The analysis followed descriptions of thematic analysis and interaction analysis.

RESULTS

The children expressed fears indirectly as cues and nonverbal signs more often than direct statements. Three children stated explicit being afraid or wanting to stop. The children worried about needle-pain, but experienced the stinging pain after the injection more bothersome. The technical instructions were detailed and comprehensive and each nurse shaped the structure of the sessions. Both nurses and parents frequently offered coping strategies unclearly without sufficient time for children to understand. We identified three main adult communication approaches (acknowledging, ambiguous and disregarding) that influenced children's expressed emotions during the training session.

CONCLUSIONS

Children's expression of fear was likely to be indirectly, and pain was mostly related to the injection rather than the needle stick. When adults used an acknowledging communication and offered sufficient coping strategies, children seemed to become involved in the procedure and acted with confidence. The initial educational training session may have a great impact on long-term repeated injections in a home setting by providing children with confidence at the onset.

Pre-consultation biopsychosocial data from patients admitted for management at pain centers in Norway

Background and aims

A bio-psycho-social approach has been recommended in multidisciplinary pain clinics, and in Norway patients with severe chronic nonmalignant pain (CNMP, defined as pain that has persisted for more than 3 months) might be treated at a regional multidisciplinary pain center. The specific aims of this study were (1) to describe characteristics of a sample of outpatients referred and accepted for treatment/management to three regional multidisciplinary pain centers in Norway, (2) to examine patient differences between the centers and (3) to study associations between symptom scores (insomnia, fatigue, depression, anxiety) and patient characteristics.

Methods

Patients, aged 17 years or older with CNMP admitted to and given a date for first consultation at one of three tertiary, multidisciplinary pain centers: St. Olavs Hospital Trondheim University Hospital (STO), Haukeland University Hospital (HUS) and University Hospital of North Norway (UNN), were included in the study. Data on demographics, physical activity, characteristics of pain, previous traumatic events, social network, Insomnia Severity Index (ISI), Chalder Fatigue Questionnaire (CFQ), Hopkins Symptom Checklist-25 (HSCL-25) and SF-36v2® were retrieved from the local quality registry at each pain center.

Results

Data from 1563 patients [mean age 42 (SD 15) years and 63% females] were available for analyses. Average years with pain were 9.3 (SD 9.1). Primary education as highest level of education was reported by 20%, being actively working/student/military by 32%, and no physical activity by 31%. Further, 48% reported widespread pain, 61% reported being exposed to serious life event(s), and 77% reported having a close friend to talk to. Non-worker status, no physical activity, lack of social network, reports of being exposed to serious life event(s) and widespread pain were all characteristics repeatedly associated with clinically high symptom scores. No significant differences between the centers were found in the proportions of patients reporting fatigue nor mean levels of insomnia symptoms. However, the proportion of patients reporting symptoms of anxiety and depression was a little lower at UNN compared with STO and HUS.

Conclusions

Analyses of registry data from three tertiary multidisciplinary pain centers in Norway support previous findings from other registry studies regarding patient characterized: A large proportion being women, many years of pain, low employment rate, low physical activity rate, and a large proportion reporting previous traumatic event(s). Characteristics such as non-work participation, no physical activity, lack of social network, have been exposed to serious life event(s), and chronic widespread pain were all associated with high clinical score levels of insomnia, fatigue, and mental distress. Health related quality of life was low compared to what has been reported for a general population and a range of other patient groups.

Implications

The findings of this study indicate that physical activity and work participation might be two important factors to address in the rehabilitation of patients with chronic non-malignant pain. Future studies should also explore whether pre consultation self-reported data might give direction to rehabilitation modalities.

Recruitment and inclusion procedures as "pain killers" in clinical trials?

Background

Recruitment and inclusion procedures in clinical trials are time critical. This holds particularly true for studies investigating patients with fluctuating symptom patterns, like those with chronic neck pain. In a feasibility study on neck pain, we found a clinically relevant decrease in pain ratings within the recruitment period. This paper analyses the phenomenon and gives recommendations for recruitment procedures in clinical trials on pain.

Methods

Changes in pain intensity scores of 44 chronic neck pain patients (6 males and 36 females; mean age: 45.3±13.2 years) between the first telephone contact and baseline assessment were analyzed. Inclusion criterion was a mean pain intensity of ≥40 on a 0-100 numerical rating scale during the last three months. Statistical analyses were performed using ANOVA and parametric/non-parametric correlation coefficients.

Results

Average pain intensity score decreased significantly from 60.3±13.3 at telephone interview to 38.1±21.7 at baseline assessment. This represents a relative change of 36.8%. A weak but significant negative correlation was found between number of days between assessments and pain rating differences. There was a positive correlation between change of pain intensity and the pain level at the first contact, indicating that the decreased pain ratings over time were also dependent on the initial pain rating.

Conclusions

The clinically significant changes in pain intensity were weakly related to waiting time and moderately dependent on initial pain intensity, suggesting regression to the mean. The natural course of the disease and the Hawthorne effect are also discussed as contributing factors.

Electrosurgery and Temperature Increase in Tissue With a Passive Metal Implant

Importance: During monopolar electrosurgery in patients, current paths can be influenced by metal implants, which can cause unintentional tissue heating in proximity to implants. Guidelines concerning electrosurgery and active implants such as pacemakers or implantable cardioverter defibrillators have been published, but most describe interference between electrosurgery and the active implant rather than the risk of unintended tissue heating. Tissue heating in proximity to implants during electrosurgery may cause an increased risk of patient injury.

Objective: To determine the temperature of tissue close to metal implants during electrosurgery in an in-vitro model.

Design, Setting, and Participants: Thirty tissue samples (15 with a metal implant placed in center, 15 controls without implant) were placed in an in vitro measurement chamber. Electrosurgery was applied at 5–60 W with the active electrode at three defined distances from the implant while temperatures at four defined distances from the implant were measured using fiber-optic sensors.

Main Outcomes and Measures: Tissue temperature increase at the four tissue sites was determined for all power levels and each of the electrode-to-implant distances. Based on a linear mixed effects model analysis, the primary outcomes were the difference in temperature increase between implant and control tissue, and the estimated temperature increase per watt per minute.

Results: Tissues with an implant had higher temperature increases than controls at all power levels after 1 min of applied electrosurgery (mean difference of 0.16°C at 5 W, 0.50°C at 15 W, 1.11°C at 30 W, and 2.22°C at 60 W, all with p < 0.001). Temperature increase close to the implant was estimated to be 0.088°C/W/min (95% CI: 0.078–0.099°C/W/min; p < 0.001). Temperature could increase to above 43°C after 1 min of 60 W. Active electrode position had no significant effect on temperature increases for tissues with implant (p = 0.6).

Conclusions and Relevance: The temperature of tissue close to a metal implant increases with passing electrosurgery current. There is a significant risk of high tissue temperature when long activation times or high power levels are used.

Understanding Pain and Pain Management in Elderly Nursing Home Patients Applying an Interprofessional Learning Activity in Health Care Students: A Norwegian Pilot Study

BACKGROUND

Pain is common among elderly patients in nursing homes. However, pain assessment and treatment are inadequate. Interprofessional treatment is recommended, and consequently interprofessional education in pain management is necessary.

AIMS

This pilot project aimed to describe how two interprofessional groups of students approached pain management in two nursing home patients.

DESIGN

We formed two teams comprising one student from the nursing, physical therapy, pharmacy, and medical educations. Each team spent one day examining a patient with chronic pain at a nursing home and they developed pain management plans.

METHODS

We collected data through video recordings during teamwork before and after examining the patients and field notes during the patient examination. We analysed the video-recordings applying the seven-step model including 1) viewing the video data, 2) describing the video data, 3) identifying critical events, 4) transcribing, 5) coding, 6) constructing storyline and 7) composing a narrative. Field notes supplied the transcripts.

RESULTS

Both teams succeeded in making a pain management plan for their patient. The common examination of the patient was crucial for the students' approaches to pain management and changed their pre-assumptions about the patients' pain. By sharing knowledge and reflecting together, the students reached a common consensus on suggestions for management of the patients' problems. Interprofessional collaboration fostered enthusiasm and a more holistic pain management approach. However, students' lack of knowledge limited their understanding of pain.

CONCLUSION

Knowledge of pain management in nursing home patients and the practice of interprofessional cooperation should be included in pain curricula for health care professionals.

Pain-relieving effectiveness, quality of life and tolerability of repeated capsaicin 8% patch treatment of peripheral neuropathic pain in Scandinavian clinical practice

Context

Clinical trials have demonstrated the efficacy and safety of the capsaicin 8% patch in patients with peripheral neuropathic pain (PNP); however, few studies have assessed this treatment in a clinical practice.

Objective

To determine whether treatment and re‐treatment with the capsaicin 8% patch reduce PNP intensity in clinical practice.

Methods

Three non‐interventional, observational studies were concurrently conducted in Denmark, Norway and Sweden. Patients with probable or definite PNP received one or two treatments with the capsaicin 8% patch according to usual clinical practice. All analyses were performed on combined data.

Results

Overall, 382 and 181 patients received treatment and re‐treatment, respectively, with the capsaicin 8% patch. At the group level, a significant reduction in mean level of ‘usual pain’ intensity (Numerical Pain Rating Scale) over the last 24 h’ score was observed from baseline to Weeks 2 through 8 [−1.05 (95% confidence interval: −1.27, 0.82); p < 0.001] with 28% and 31% of patients reporting a ≥30% reduction in pain after first treatment and re‐treatment, respectively. Improvements in health‐related quality of life (EQ‐5D‐3L index) and overall health status (Patient Global Impression of Change) were observed early (Week 1) and throughout the treatment periods. Most application site reactions subsided within a week after treatment. Following treatment and re‐treatment, 57% and 71% of patients, respectively, were willing to undergo further treatment with the capsaicin 8% patch.

Conclusion

In Scandinavian clinical practice, capsaicin 8% patch treatment was associated with significant reductions in pain intensity and was well tolerated with over half of patients willing to undergo re‐treatment.

Sedation of Patients in Intensive Care Medicine and Nursing: ethical issues

This article focuses on the ethical aspects of medically-induced sedation and pain relief in intensive care medicine. The study results reported are part of a larger investigation of patients’ experiences of being sedated and receiving pain relief, and also families’ experiences of having a close relative under controlled sedation in an intensive care unit.

The study is based on qualitative in-depth interviews with nine nurses and six doctors working in intensive care and surgical units in a major Norwegian hospital. The textual data are interpreted according to Kvale’s method for analyzing qualitative data.

There are ethical problems regarding how to achieve an acceptable balance between a patient’s subjective well-being and the medical need for reduced sedation. The authors discuss whether some medical reasons for reduced sedation are ethically justifiable, given the actual medical knowledge available. The study also addresses the ethical consequences of reducing medically-induced sedation and the demands it puts on interdisciplinary co-operation and communication, as well as the importance of improving the quality of medical and nursing care.

Trait-anxiety and pain intensity predict symptoms related to dysfunctional breathing (DB) in patients with chronic pain

Aims

The purpose of this cross-sectional study was to inves-tigate the occurrence of symptoms related to dysfunctional breathing (DB) in chronic pain patients and to examine factors associated with these symptoms.

Methods

A questionnaire was sent to 527 adults referred to out-patient pain clinics at Oslo university hospital. The questionnaire provided demographic data, Brief Pain Inventory, Spielberger state- trait anxiety inventory, and Nijmegen questionnaire (NQ). Multiple regression analyses were performed using SPSS.

Results

A total of 108 patients (20%) responded to the questionnaire and was included. Mean age was 49 years and two third of the participants were female. More than four out of ten had a NQ score ≥ 23 (a conservative cutoff value for DB). The median NQ score in the sample was 19. Trait-anxiety (Beta = .412, p < 0.001) and maximal pain intensity during the past week (Beta = .264, p = 0.004) predicted symptoms related to DB even when controlling for age and gender.

Conclusions

The study shows that a large portion of patients with chronic pain experiences symptoms that have been associated with hyperventilation and DB and at a higher level than previously reported. Although trait-anxiety is a strong predictor for symptoms related to DB, we find it interesting that maximal pain intensity during the last week also was associated with these symptoms. The cross-sectional design, low response rate, and lack of diagnoses limit our ability to draw conclusions about causal relationship and extrapolate to a larger populations of patients with chronic pain.

Health related quality of life in adolescents with chronic fatigue syndrome: a cross-sectional study

Aim

To study health related quality of life (HRQOL) and depressive symptoms in adolescents with chronic fatigue syndrome (CFS) and to investigate in which domains their HRQOL and depressive symptoms differ from those of healthy adolescents.

Background and objective

Several symptoms such as disabling fatigue, pain and depressive symptoms affect different life domains of adolescents with CFS. Compared to adolescents with other chronic diseases, young people with CFS are reported to be severely impaired, both physiologically and mentally. Despite this, few have investigated the HRQOL in this group.

Method

This is a cross-sectional study on HRQOL including 120 adolescents with CFS and 39 healthy controls (HC), between 12 and 18 years. The Pediatric Quality of Life Inventory™, 4.0 (PedsQL) was used to assess HRQOL. The Mood and Feelings Questionnaire assessed depressive symptoms. Data were collected between March 2010 and October 2012 as part of the NorCAPITAL project (Norwegian Study of Chronic Fatigue Syndrome in Adolescents: Pathophysiology and Intervention Trial). Linear and logistic regression models were used in analysis, and all tests were two-sided.

Results

Adolescents with CFS reported significantly lower overall HRQOL compared to HCs. When controlling for gender differences, CFS patients scored 44 points lower overall HRQOL on a scale from 0–100 compared to HCs. The domains with the largest differences were interference with physical health (B = −59, 95 % CI −54 to −65) and school functioning (B = −52, 95 % CI −45 to −58). Both depressive symptoms and being a patient were independently associated with lower levels of HRQOL

Conclusion

The difference in HRQOL between CFS patients and healthy adolescents was even larger than we expected. The large sample of adolescents with CFS in our study confirms previous findings from smaller studies, and emphasizes that CFS is a seriously disabling condition that has a strong impact on their HRQOL. Even though depressive symptoms were found in the group of patients, they could not statistically explain the poor HRQOL.

Pain and pressure pain thresholds in adolescents with chronic fatigue syndrome and healthy controls: a cross-sectional study

OBJECTIVES

Although pain is a significant symptom in chronic fatigue syndrome (CFS), pain is poorly understood in adolescents with CFS. The aim of this study was to explore pain distribution and prevalence, pain intensity and its functional interference in everyday life, as well as pressure pain thresholds (PPT) in adolescents with CFS and compare this with a control group of healthy adolescents (HC).

METHODS

This is a case-control, cross-sectional study on pain including 120 adolescents with CFS and 39 HCs, aged 12-18 years. We measured pain frequency, pain severity and pain interference using self-reporting questionnaires. PPT was measured using pressure algometry. Data were collected from March 2010 until October 2012 as part of the Norwegian Study of Chronic Fatigue Syndrome in Adolescents: Pathophysiology and Intervention Trial.

RESULTS

Adolescents with CFS had significantly lower PPTs compared with HCs (p<0.001). The Pain Severity Score and the Pain Interference Score were significantly higher in adolescents with CFS compared with HCs (p<0.001). Almost all adolescents with CFS experienced headache, abdominal pain and/or pain in muscles and joints. Moreover, in all sites, the pain intensity levels were significantly higher than in HCs (p<0.001).

CONCLUSIONS

We found a higher prevalence of severe pain among adolescents with CFS and lowered pain thresholds compared with HCs. The mechanisms, however, are still obscure. Large longitudinal population surveys are warranted measuring pain thresholds prior to the onset of CFS.

TRIAL REGISTRATION NUMBER

Clinical Trials, NCT01040429; The Norwegian Study of Chronic Fatigue Syndrome in Adolescents: Pathophysiology and Intervention Trial (NorCAPITAL) http://www.clinicaltrials.gov.

[Post-operative pain management in hospitals]

BACKGROUND

Relief of post-operative pain has a bearing on the patient's well-being, mobilisation and time confined to bed. The article discusses indications, contraindications and the efficacy of the various treatment modalities.

MATERIAL AND METHOD

We have examined review articles, meta-analyses and randomised controlled trials, identified through literature searches in PubMed.

RESULTS

The use of several medicines and techniques (multimodal pain treatment) is necessary to achieve a good balance between pain relief, side effects and risk. Systemic administration of paracetamol, NSAIDs, opioids and glucocorticoids is effective for post-operative pain. The same applies to epidural analgesia, peripheral nerve blocks and local anaesthetic wound infiltration. Subanaesthetic doses of ketamine have an opioid-sparing effect, but the optimal dosing regimen is uncertain. Gabapentinoids have an effect on post-operative pain, but the effect appears to vary depending on the type of operation and analgesic regimen. The effect of one analgesic will depend on which other drugs are used in multimodal pain treatment. Epidural analgesia, peripheral nerve blocks or extensive local infiltration analgesia is often necessary to relieve movement-related pain.

INTERPRETATION

Many treatment modalities are effective for post-operative pain. It is crucial that the treatment is well organised and that it includes routines for systematic pain assessment, efficacy and side effects of the pain management.

[The intern's vein--the patient's nightmare?]

BACKGROUND

Punction of blood vessels is a necessity in modern medicine, but there is a paucity of knowledge about the close relation between vessels and nerves.

MATERIAL AND METHODS

We refer to two cases that show possible consequences of cannulation of v. cephalica and a. radialis.

RESULTS

Both patients developed clinical symptoms and neurological findings indicating injury of the radial nerve. One of the patients is not likely to develop chronic neuropathic pain, but in the other patient the similar injury of the radial nerve has lead to chronic and disabling pain.

INTERPRETATION

We advise against using the distal part of v. cephalica (the intern's vein) as the first choice for training of inexperienced students. The vein should only be used in patients that lack other venous alternatives and in acute situations where quick infusions or blood transfusions are needed.

A randomized double-blind controlled trial of intra-annular radiofrequency thermal disc therapy--a 12-month follow-up

The discTRODE probe applies radiofrequency (RF) current, heating the annulus to treat chronic discogenic low back pain. Randomized controlled studies have not been published. We assessed the long-term effect and safety aspects of percutaneous intradiscal radiofrequency thermocoagulation (PIRFT) with the discTRODE probe in a prospective parallel, randomized and gender stratified, double-blind placebo-controlled study. Twenty selected patients with chronic low back pain and a positive one-level pressure-controlled provocation discography were randomized to either intra-annular PIRFT or intra-annular sham treatment. A blinded interim analysis was performed when 20 patients had been followed for six months. The 6-month analysis did not reveal any trend towards overall effect or difference between active and sham treatment for the primary endpoint: change in pain intensity (0-10). The inclusion of patients was therefore discontinued. After 12 months the overall reduction from baseline pain had reached statistical significance, but there was no significant difference between the groups. The functional outcome measures (Oswestry Disability Index, and SF 36 subscales and the relative change in pain) appeared more promising, but did not reach statistical significance when compared with sham treatment. Two actively treated and two sham-treated patients reported increased pain levels, and in both groups a higher number was unemployed after 12 months. The study did not find evidence for a benefit of PIRFT, although it cannot rule out a moderate effect. Considering the high number, reporting increased pain in our study, we would not recommend intra-annular thermal therapy with the discTRODE probe.

Assessment of pain

Valid and reliable assessment of pain is essential for both clinical trials and effective pain management. The nature of pain makes objective measurement impossible. Acute pain can be reliably assessed, both at rest (important for comfort) and during movement (important for function and risk of postoperative complications), with one-dimensional tools such as numeric rating scales or visual analogue scales. Both these are more powerful in detecting changes in pain intensity than a verbal categorical rating scale. In acute pain trials, assessment of baseline pain must ensure sufficient pain intensity for the trial to detect meaningful treatment effects. Chronic pain assessment and its impact on physical, emotional, and social functions require multidimensional qualitative tools and health-related quality of life instruments. Several disease- and patient-specific functional scales are useful, such as the Western Ontario and MacMaster Universities for osteoarthritis, and several neuropathic pain screening tools. The Initiative on

METHODS

Measurement, and Pain Assessment in Clinical Trials recommendations for outcome measurements of chronic pain trials are also useful for routine assessment. Cancer pain assessment is complicated by a number of other bodily and mental symptoms such as fatigue and depression, all affecting quality of life. It is noteworthy that quality of life reported by chronic pain patients can be as much affected as that of terminal cancer patients. Any assessment of pain must take into account other factors, such as cognitive impairment or dementia, and assessment tools validated in the specific patient groups being studied.

Quality of life after randomization to laparoscopic versus open living donor nephrectomy: long-term follow-up

BACKGROUND

The aim of this randomized study was to compare patient-reported outcome after laparoscopic versus open donor nephrectomy during 1 year follow-up. The evidence base has so far not allowed for a decision as to which method is superior as seen from a long-term quality of life-perspective.

METHODS

The donors were randomized to laparoscopic (n=63) or open (n=59) nephrectomy, with follow-up at 1, 6, and 12 months. Primary outcomes were health status (SF-36) and overall quality of life (QOLS-N). Secondary outcomes were donor perception of the surgical scar, the donation's impact on personal finances, and whether the donor would make the same decision to donate again.

RESULTS

There was a significant difference in favor of laparoscopic surgery regarding the SF-36 subscale bodily pain at 1 month postoperatively (P<0.05). Analysis based on intention to treat revealed no long-term differences between groups in SF-36 scores. When subtracting the reoperated/converted donors of the laparoscopic group, significant differences in favor of laparoscopy were revealed in the subscales bodily pain at 6 months (P<0.05) and social functioning at 12 months (P<0.05). No significant differences were found in QOLS-N scores between groups.

CONCLUSIONS

Laparoscopic donor nephrectomy is an attractive alternative to open donor nephrectomy because of less postoperative pain. However, long-term comparison only revealed significant differences in favor of laparoscopy when adjusting for reoperations/conversions. Both groups reached baseline scores in most SF-36 subscales at 12 months and this may explain why possible minor benefits are hard to prove.

Catecholamine-induced excitation of nociceptors in sympathetically maintained pain

Sympathetically maintained pain could either be mediated by ephaptic interactions between sympathetic efferent and afferent nociceptive fibers or by catecholamine-induced activation of nociceptive nerve endings. We report here single fiber recordings from C nociceptors in a patient with sympathetically maintained pain, in whom sympathetic blockade had repeatedly eliminated the ongoing pain in both legs. We classified eight C-fibers as mechano-responsive and six as mechano-insensitive nociceptors according to their mechanical responsiveness and activity-dependent slowing of conduction velocity (latency increase of 0.5+/-1.1 vs. 7.1+/-2.0 ms for 20 pulses at 0.125 Hz). Two C-fibers were activated with a delay of several seconds following strong endogenous sympathetic bursts; they were also excited for about 3 min following the injection of norepinephrine (10 microl, 0.05%) into their innervation territory. In these two fibers, a prolonged activation by injection of low pH solution (phosphate buffer, pH 6.0, 10 microl) and sensitization of their heat response following prostaglandin E2 injection were recorded, evidencing their afferent nature. Moreover, their activity-dependent slowing was typical for mechano-insensitive nociceptors. We conclude that sensitized mechano-insensitive nociceptors can be activated by endogenously released catecholamines and thereby may contribute to sympathetically maintained pain. No evidence for ephaptic interaction between sympathetic efferent and nociceptive afferent fibers was found.

Postoperative pain and convalescence in living kidney donors-laparoscopic versus open donor nephrectomy: a randomized study

The aim of the present study was to compare postoperative pain and convalescence in patients randomized to laparoscopic or open donor surgery in a prospective, controlled trial. The donors were randomly assigned to undergo laparoscopic (n = 63) or open (n = 59) donor nephrectomy. Our end points were amount of administered analgesics in the recovery period, postoperative pain on the second postoperative day and at one month after surgery and duration of sick leave. There was a significant difference in favor of the laparoscopic group regarding administered analgesics on day of surgery (p < 0. 02). No difference was observed between groups regarding self-reported pain on the second postoperative day. One month post donation, significantly fewer donors in the laparoscopic group reported pain (p < 0. 02) or had used analgesics (p < 0.05). The duration of sick leave was significantly shorter in the laparoscopic group (p = 0.01). The laparoscopic group experienced a more rapid convalescence and a shorter period of sick leave. Although immediate postoperative pain can be managed efficiently regardless of procedure, a lower consumption of opioids and incidence of pain in the convalescent period suggest a clinically relevant patient-experienced benefit from a successful laparoscopic procedure.

Laparoscopic versus Open Living-Donor Nephrectomy: Experiences from a Prospective, Randomized, Single-Center Study Focusing on Donor Safety

BACKGROUND

Very few randomized studies on laparoscopic (L) versus open (O) living-donor nephrectomy (LDN) have been presented. The largest randomized series reported so far included 80 donors. In 2000, an Australian safety group concluded that the evidence base for L-LDN is inadequate to make recommendations regarding safety and efficacy.

METHODS

With this background, at our single national center, 122 donors were randomized to left-sided L-LDN (n=63) or O-LDN (n=59), from February 2001 to May 2004. This article summarizes our experiences, in particular regarding complications and safety.

RESULTS

There were significant differences in favor of O-LDN regarding operative time, warm ischemia time, and vessel lengths, whereas the analgesic requirements and pain data were significantly in favor of the laparoscopic procedure. In the L-LDN group, there were five major postoperative complications resulting in reoperations (8%), including two intestinal perforations. No major complications occurred in the O-LDN group.

CONCLUSIONS

These results from our randomized study do suggest that conventional O-LDN is a very secure procedure, superior to L-LDN regarding donor safety. There has been an unacceptably high rate of reoperations in our L-LDN series but without mortality or significant sequelae. A careful look at some other L-LDN series also suggests increased morbidity/mortality. Our data do, however, support the view that a perfect, uncomplicated L-LDN appears to be the superior procedure, and the laparoscopic procedure is still evolving. Donor safety may be improved by avoiding obese donors, stapling of the renal artery (not clipping), and perhaps by hand assistance. Furthermore, we will consider the retroperitoneal approach.

Detection of ischemia by PCO2 before adenosine triphosphate declines in skeletal muscle

OBJECTIVE

Ischemia is a serious problem in clinical medicine, and effective methods are needed to detect ischemia before the injury becomes irreversible. In experimental studies on several organs, PCO2 was found to increase rapidly after the onset of supply-dependent anaerobic metabolism. A shortcoming of these studies was that PCO2 was not correlated with tissue concentrations of lactate and the energy status in the cell. Thus, in this study we have measured tissue concentrations of lactate, phosphocreatine, and adenosine triphosphate. We hypothesized that during ischemic conditions, PCO2 reflects lactate generation in the cell and not exhausted energy stores per se. If this is the case, PCO2 can be used to detect ischemia before the energy stores are depleted. Consequently, therapy can be instituted at a time when the organ is salvageable.

DESIGN

Prospective laboratory study.

SETTING

University research laboratory.

SUBJECTS

Seven pigs.

INTERVENTIONS

In a porcine model, gluteal skeletal muscles with no-flow ischemia were examined. PCO2 was measured both in situ and in vitro at increasing periods of time. Concomitantly, tissue lactate, adenosine triphosphate, and phosphocreatine were analyzed.

MEASUREMENTS AND MAIN RESULTS

Tissue surface CO2 tension (PtCO2) increased rapidly after onset of ischemia. From a baseline of 63 +/- 3 torr (8.4 +/- 1.2 kPa) under aerobic conditions, it increased to 157 +/- 6 torr (21 +/- 2.2 kPa) after 30 mins of ischemia and 386 +/- 9 torr (51.5 +/- 3 kPa) at 120 mins. The rapid increase of PtCO2 correlated well with increasing values of lactate (r2 >.9) in the tissue. Adenosine triphosphate was essentially unchanged for 45 mins after onset of ischemia, after which it declined. Phosphocreatine decreased earlier than adenosine triphosphate in accordance with the notion that high-energy phosphate groups are transferred from phosphocreatine to adenosine triphosphate.

CONCLUSION

In this porcine model of skeletal muscle ischemia, PtCO2 correlates well with tissue lactate and increases long before the energy stores of phosphocreatine and most notably adenosine triphosphate are severely reduced. Thus, PtCO2 could be monitored to detect and treat earlier stages of ischemia.

Tissue Carbon Dioxide Tension:

Free flap surgical procedures are technically challenging, and anastomosis failure may lead to arterial or venous occlusion and flap necrosis. To improve myocutaneous flap survival rates, more reliable methods to detect ischemia are needed. On the basis of theoretical considerations, carbon dioxide tension, reflecting intracellular acidosis, may be suitable indicators of early ischemia. It was hypothesized that tissue carbon dioxide tension increased rapidly when metabolism became anaerobic and would be correlated with acute venoarterial differences in lactate levels, potassium levels, and acid-base parameters. Because metabolic disturbances have been observed to be less pronounced in flaps with venous occlusion, it was hypothesized that tissue carbon dioxide tension and venoarterial differences in lactate and potassium levels and acid-base parameters would increase less during venous occlusion than during arterial occlusion. In 14 pigs, latissimus dorsi myocutaneous flaps were surgically isolated, exposed to acute ischemia for 150 minutes with complete arterial occlusion (seven subjects) or venous occlusion (seven subjects), and reperfused for 30 minutes. After arterial occlusion, pedicle blood flow decreased immediately to less than 10 percent of baseline flow. Blood flow decreased more slowly after venous occlusion but within 3 minutes reached almost the same low levels as observed during arterial occlusion. Venous oxygen saturation decreased from approximately 70 percent to approximately 20 percent, whereas oxygen uptake was almost arrested. Tissue carbon dioxide tension increased to two times baseline values in both groups (p < 0.01). The venoarterial differences in carbon dioxide tension, pH, base excess, glucose levels, lactate levels, and potassium levels increased significantly (p < 0.01). Tissue carbon dioxide tension measured during the occlusion period were closely correlated with venoarterial differences in pH, base excess, glucose levels, lactate levels, and potassium levels (median r2, 0.67 to 0.92). After termination of arterial or venous occlusion, more pronounced hyperemia was observed in the arterial occlusion group than in the venous occlusion group (p < 0.05). Oxygen uptake (p < 0.05) and venoarterial differences in lactate and potassium levels (p < 0.05) were significantly more pronounced in the arterial occlusion group. In the venous occlusion group, with less pronounced hyperemia, venoarterial differences in acid-base parameters remained significantly different from baseline values before occlusion (p < 0.01). The data indicate that tissue carbon dioxide tension can be used to detect anaerobic metabolism, caused by arterial or venous occlusion, in myocutaneous flaps. The correlations between carbon dioxide tension and venoarterial differences in acid-base parameters were excellent. Because carbon dioxide tension can be measured continuously in real time, such measurements are more likely to represent a clinically useful parameter than are venoarterial differences.

Detection of organ ischemia during hemorrhagic shock

BACKGROUND

In a porcine hemorrhagic shock model we aimed to determine: (a) whether blood flow to the intestine and kidney was more reduced than cardiac output; (b) whether parameters of anaerobic metabolism correlated with regional blood flow; and (c) whether metabolic parameters in intestine, kidney and skeletal muscles detected a compromised metabolic state at an earlier stage than did systemic parameters.

METHODS

In an animal research laboratory at a university hospital six domestic pigs were subjected to volume-controlled hemorrhage. Every 30 min samples of blood were withdrawn. Systemic and regional hemodynamic parameters and tissue levels of PCO2 were monitored. Whole body and organ-specific oxygen consumption (VO2) and veno-arterial (VA) differences of lactate, glucose, potassium (K+), PCO2, H+ and base excess (BE) were calculated every 30 min.

RESULTS

With progressive hemorrhage, intestinal blood flow decreased to the same extent as cardiac output, whereas the reduction in renal blood flow was more pronounced. We found a concomitant reduction in VO2 (onset of supply dependent metabolism) in intestine, kidney and skeletal muscles. In muscular tissue PCO2 increased to levels three times higher than baseline, while renal and intestinal PCO2 increased eightfold. Supply dependency was associated with a concomitant increase in VA CO2 and VA H+. Also, VA lactate increased, mostly in intestine and least in skeletal muscle. Intestinal and renal VA K+ increased, while muscular VA K+ decreased. Arterial lactate and H+ increased considerably, whereas arterial BE decreased.

CONCLUSION

With progressive hemorrhage, renal blood flow, but not intestinal and skeletal muscle blood flow, was reduced more than cardiac output. Supply dependent oxygen metabolism (VO2) and organ acidosis occurred simultaneously in the three organs, despite differences in blood flow reductions. Organ ischemia coincided with a pronounced change in arterial lactate and systemic acid base parameters.

PCO(2) in the large intestine of mice, rats, guinea pigs, and dogs and effects of the dietary substrate

PCO(2) in the lumen and serosa of cecum and colon was measured in rats, guinea pigs, and dogs to examine the relationship between serosal PCO(2) and the incidence of intestinal necrotic lesions after administration of gas-carrier contrast agents in rodents. The effects of the dietary substrate were tested in a group of mice maintained on a diet based on glucose as the only carbohydrate source. The anesthetic used was a fentanyl-fluanison-midazolam mixture (rodents) and pentobarbital (dogs). PCO(2) was measured in vivo and postmortem, and the kinetics of the postmortem serosal PCO(2) [transmural CO(2) flux (J(CO(2)))] was calculated. PCO(2) in the cecal serosa and lumen, respectively, was 64 +/- 4 and 392 +/- 18 Torr in rats, 67 +/- 3 and 276 +/- 17 Torr in guinea pigs, and 73 +/- 6 and 137 +/- 7 Torr in mice on glucose-based diet. In the colon serosa and lumen of dogs, PCO(2) was 30 +/- 6 and 523 +/- 67 Torr, respectively. Serosal PCO(2) increased rapidly after death in rats and slower in guinea pigs and mice, and the slowest change was observed in dogs. Compared with dogs, serosal PCO(2) and J(CO(2)) of rats and guinea pigs were significantly higher. Serosal PCO(2) of guinea pigs was similar to that of rats, whereas the J(CO(2)) of guinea pigs was significantly lower. These data suggest a causal relationship between the ability of the cecal and colonic wall to act as a barrier to CO(2) diffusion and the presence of characteristic gas-carrier contrast agent-induced intestinal lesions in mice and rats and their absence in guinea pigs, dogs, and other species.

MRI-guided celiac plexus block

Celiac plexus block is used as a palliative procedure in cases of severe upper abdominal pain caused by pancreatitis or tumors of the pancreas. It can be guided by bony landmarks, fluoroscopy, ultrasound (US), or computed tomography (CT). To avoid severe complications, methods visualizing soft tissue, like CT and magnetic resonance (MR) imaging, are preferable. We describe celiac plexus blocks carried out in an open MR scanner, offering needle guidance with an optical tracking system and near real-time image acquisition. Eight patients with severe chronic abdominal pain were included. In these, 14 celiac blocks were carried out. Good or total pain relief was achieved in 8 of the 14 blocks (57%), a moderate effect in 5 blocks (36%), and no effect in 1 block (7%). The placement of the needle was easily guided with MR in all cases. The MR technique ensures good visualization of soft tissue, direct monitoring of needle movement and avoids exposure to ionizing radiation. Celiac plexus block can safely be carried out in an open MR scanner.

Gas supersaturation in the cecal wall of mice due to bacterial CO2 production

PCO2 in the lumen and serosa of cecum and jejunum was measured in mice. The anesthetic used was a fentanyl-fluanisone-midazolam mixture. PCO2 was recorded in vivo and postmortem. PCO2 was 409 +/- 32 Torr (55 +/- 4 kPa) in the cecal lumen and 199 +/- 22 Torr (27 +/- 3 kPa) on the serosa in normal mice. Irrigation of the cecum resulted in serosal and luminal PCO2 levels of 65-75 Torr. Cecal PCO2 was significantly lower in germ-free mice (65 +/- 5 Torr). Cecal PCO2 increased significantly after introduction of normal bacterial flora into germ-free mice. Introduction of bacterial monocultures into germ-free mice had no effect. After the deaths of the mice, cecal PCO2 increased rapidly in normal mice. The intestinal bacteria produced the majority of the cecal PCO2, and the use of tonometry in intestinal segments with a high bacterial activity should be interpreted with caution. We propose that serosal PCO2 levels >150-190 Torr (20-25 kPa) in the cecum of mice with a normal circulation may represent a state of gas supersaturation in the cecal wall.

[CO2 pressure used in the diagnosis of ischemia]

Under ischemic conditions O2 delivery is insufficient, and the cells convert to anaerobic metabolism with production of lactic acid. The protons formed in this process are to a large extent rapidly buffered inside the cell by proteins and HCO3-. Protons buffered by HCO3- form CO2 in the tissue. Since the blood supply during ischemia is minimal, CO2 is not transported away from the tissue and will reach tensions far above pCO2 found under aerobic conditions. Thus, measuring pCO2 can be used to detect ischemia in an organ. Gastrointestinal tonometry is based on the concept of CO2 accumulation during anaerobiosis. It has been customary to calculate so-called interstitial pH (pHi) by incorporating the measured pCO2 in the tonometer and the HCO3- in an arterial blood gas in the Henderson-Hasselbalch equation. However, this method has several weaknesses, and we recommend using the measured pCO2, or rather the difference between gastrointestinal and arterial pCO2. Experimental studies have shown that pCO2 electrodes sensitively detect the onset of ischemia also in solid organs. The accumulation of pCO2 coincides with the shift from supply-independent to supply-dependent oxygen consumption and correlates with other markers of ischemia. pCO2 measurement at organ level is a promising tool in the monitoring of organ ischemia.

PCO2 electrodes at the surface of the kidney detect ischaemia

BACKGROUND

Under ischaemic (anaerobic) conditions there will be an accumulation of CO2 in the tissue secondary to a build up of protons that is buffered by HCO3. We reasoned that CO2 could be measured at the surface of the kidney by PCO2 electrodes to detect ischaemic conditions.

METHODS

Anaesthetized, mechanically ventilated pigs (25-30 kg) were investigated. Two acute porcine models, one of haemorrhagic shock and one of renal artery stenosis were used. Renal blood flow was gradually decreased, either by successive episodes of bleeding through the arterial cannula or by successive snaring of the renal artery.

RESULTS

In both models we found that with decreased blood flow but maintained aerobic metabolism (supply independence) PCO2 both at the surface of the kidney and in the renal vein increased by 2-3 kPa. Thus, the tissue-venous PCO2 difference did not change much. At DO2crit, i.e., at the transition to supply-dependent O2 consumption, the tissue PCO2 started to increase rapidly, as did the tissue-venous PCO2 difference. This is compatible with the notion that a hallmark of ischaemia is decreased ability of the blood to transport away waste products because the contact between large parts of tissue and blood is virtually non-existent. In the renal artery stenosis model kidney surface PCO2 values rose from a baseline of 6.6 +/- 0.6 kPa (mean +/- SEM) to a value near DO2crit of 10.6 +/- 0.8 kPa, reaching a final value of 29.9 +/- 3.5 kPa at no flow. PCO2 in the renal vein, however, reached a maximum of only 8.2 +/- 0.6 kPa. Numbers very similar to these were also found in the haemorrhagic model. The urine production decreased before the onset of ischaemia. When surface PCO2 values increased sharply indicating ischaemia, the urine production was zero. Lactate production by the kidney correlated very well with increasing tissue PCO2 values further corroborating that anaerobic metabolism was detected with the electrodes.

CONCLUSION

We conclude that PCO2 electrodes placed at the surface of the kidney detect renal cortical ischaemia.

The duration of acute respiratory tract infections in children

In a rural district in Western Norway with 400 children under 16 years, we recorded all children with acute respiratory infections who attended their general practitioner during a period of four months. 90 cases were recorded, giving an incidence of 5.6% per month. Half of the patients contacted the doctor within four days from the initial symptom, every sixth waited more than two weeks. Their symptoms were monitored by the parents. Low fever, nasal discharge and cough were the most long-standing symptoms. After three weeks less than 50% of the patients were completely recovered. The children under one year of age recovered more quickly than the rest. No serious complications or sequelae were recorded.