Dynamic cerebral autoregulation is preserved during orthostasis and intrathoracic pressure regulation in healthy subjects: A pilot study

Resistance breathing may restore cardiac output (CO) and cerebral blood flow (CBF) during hypovolemia. We assessed CBF and cerebral autoregulation (CA) during tilt, resistance breathing, and paced breathing in 10 healthy subjects. Blood velocities in the internal carotid artery (ICA), middle cerebral arteries (MCA, four subjects), and aorta were measured by Doppler ultrasound in 30° and 60° semi-recumbent positions. ICA blood flow and CO were calculated. Arterial blood pressure (ABP, Finometer), and end-tidal CO2 (ETCO2) were recorded. ICA blood flow response was assessed by mixed-models regression analysis. The synchronization index (SI) for the variable pairs ABP-ICA blood velocity, ABP-MCA velocities in 0.005-0.08 Hz frequency interval was calculated as a measure of CA. Passive tilting from 30° to 60° resulted in 12% decrease in CO (p = 0.001); ICA blood flow tended to fall (p = 0.04); Resistance breathing restored CO and ICA blood flow despite a 10% ETCO2 drop. ETCO2 and CO contributed to ICA blood flow variance (adjusted R2: 0.9, p < 0.0001). The median SI was low (<0.2) indicating intact CA, confirmed by surrogate date testing. The peak SI was transiently elevated during resistance breathing in the 60° position. Resistance breathing may transiently reduce CA efficiency. Paced breathing did not restore CO or ICA blood flow.

Pregnant women with acute respiratory distress syndrome triggered by COVID-19

Background

Pregnant women with COVID-19 are probably at increased risk of serious illness. The objective of this study was to describe the course of illness in pregnant women admitted to the intensive care unit (ICU) with acute respiratory distress syndrome triggered by COVID-19.

Material and method

Pregnant women with COVID-19 were registered on admission to an ICU at Rikshospitalet, Oslo University Hospital in the period March 2020 to May 2023. We reviewed the patients' medical records retrospectively and describe clinical trajectories, management parameters and laboratory data collected during the period in intensive care. Self-perceived health was surveyed 15 months after discharge from intensive care.

Results

Thirteen pregnant women were admitted in the period from February to December 2021. All met criteria for acute respiratory distress syndrome (ARDS) and were treated with corticosteroids and mechanical ventilation according to current guidelines. None of the patients had been vaccinated against COVID-19. Ten patients were orally intubated after therapeutic failure with non-invasive mechanical ventilation. One patient was treated with extracorporeal membrane oxygenation (ECMO). All patients survived their stay in intensive care, but there were two cases of intrauterine fetal demise. Almost half of the patients reported moderate to significantly reduced self-perceived health and quality of life 15 months after discharge from intensive care.

Interpretation

All pregnant women admitted to an ICU at Rikshospitalet, Oslo University Hospital with ARDS triggered by COVID-19 survived hospitalisation, but several had symptoms that persisted long after their stay in the ICU.

Ekstrakorporal membranoksygenering ved akutt lungesviktsyndrom hos covid-19-pasienter

BACKGROUND

COVID-19 can lead to acute respiratory distress syndrome (ARDS). In some patients for whom conventional mechanical ventilation is insufficient, venovenous (VV) extracorporeal membrane oxygenation (ECMO) can be life-saving.

MATERIAL AND METHOD

Retrospective analysis of data from patients with ARDS triggered by COVID-19 who received ECMO therapy between March 2020 and February 2022. Premorbid health condition, course of respiratory distress and respiratory support before, during and after ECMO therapy were registered.

RESULTS

Thirty patients received ECMO therapy. Median age was 57 years, median body mass index 28 kg/m2, and 23 patients were men. Median duration of lung protective mechanical ventilation with tidal volume 5.8 mL/kg predicted body weight before initiation of ECMO therapy was 8 days. Treatment indication was primarily severe hypoxaemia, frequently combined with hypercapnia. Twenty-three patients developed at least one severe complication while receiving ECMO therapy. Sixteen patients died, 13 during ongoing ECMO therapy. Fourteen were discharged from hospital. Median duration of ECMO and mechanical ventilation was 27 and 37 days, respectively.

INTERPRETATION

ECMO therapy for patients with ARDS triggered by COVID-19 can be life-saving, but the treatment is accompanied by severe complications and a high mortality rate.

The association of prior paracetamol intake with outcome of very old intensive care patients with COVID-19: results from an international prospective multicentre trial

BACKGROUND

In the early COVID-19 pandemic concerns about the correct choice of analgesics in patients with COVID-19 were raised. Little data was available on potential usefulness or harmfulness of prescription free analgesics, such as paracetamol. This international multicentre study addresses that lack of evidence regarding the usefulness or potential harm of paracetamol intake prior to ICU admission in a setting of COVID-19 disease within a large, prospectively enrolled cohort of critically ill and frail intensive care unit (ICU) patients.

METHODS

This prospective international observation study (The COVIP study) recruited ICU patients ≥ 70 years admitted with COVID-19. Data on Sequential Organ Failure Assessment (SOFA) score, prior paracetamol intake within 10 days before admission, ICU therapy, limitations of care and survival during the ICU stay, at 30 days, and 3 months. Paracetamol intake was analysed for associations with ICU-, 30-day- and 3-month-mortality using Kaplan Meier analysis. Furthermore, sensitivity analyses were used to stratify 30-day-mortality in subgroups for patient-specific characteristics using logistic regression.

RESULTS

44% of the 2,646 patients with data recorded regarding paracetamol intake within 10 days prior to ICU admission took paracetamol. There was no difference in age between patients with and without paracetamol intake. Patients taking paracetamol suffered from more co-morbidities, namely diabetes mellitus (43% versus 34%, p < 0.001), arterial hypertension (70% versus 65%, p = 0.006) and had a higher score on Clinical Frailty Scale (CFS; IQR 2-5 versus IQR 2-4, p < 0.001). Patients under prior paracetamol treatment were less often subjected to intubation and vasopressor use, compared to patients without paracetamol intake (65 versus 71%, p < 0.001; 63 versus 69%, p = 0.007). Paracetamol intake was not associated with ICU-, 30-day- and 3-month-mortality, remaining true after multivariate adjusted analysis.

CONCLUSION

Paracetamol intake prior to ICU admission was not associated with short-term and 3-month mortality in old, critically ill intensive care patients suffering from COVID-19.

TRIAL REGISTRATION

This prospective international multicentre study was registered on ClinicalTrials.gov with the identifier "NCT04321265" on March 25, 2020.

Monitoring the Awake and Anesthetized Unconscious States Using Bispectral Index and Electroencephalographic Connectivity Measures

Objective. Our objective was to compare three electroencephalography (EEG)-based methods with anesthesiologist clinical judgment of the awake and anesthetized unconscious states. Methods. EEG recorded from 25 channels and from four channel bilateral Bispectral index (BIS) electrodes were collected from 20 patients undergoing surgery with general anesthesia. To measure connectivity we applied Directed Transfer Function (DTF) in eight channels of the EEG, and extracted data from BIS over the same time segments. Shannon's entropy was applied to assess the complexity of the EEG signal. Discriminant analysis was used to evaluate the data in relation to clinical judgment. Results. Assessing anesthetic state relative clinical judgment, the bilateral BIS gave the highest accuracy (ACC) (95.4%) and lowest false positive discovery rate (FDR) (0.5%) . Equivalent DTF gave 94.5% for ACC and 2.6% for FDR. Combining all methods gave ACC = 94.9% and FDR = 1%. Generally, entropy scored lower on ACC and higher on FDR than the other methods (ACC 90.87% and FDR 4.6%). BIS showed at least a one minute delay in 18 of the 20 patients. Conclusions. Our results show that BIS and DTF both have a high ACC and low FDR. Because of time delays in BIS values, we recommend combining the two methods.

Noninvasive ventilation in COVID-19 patients aged ≥ 70 years-a prospective multicentre cohort study

BACKGROUND

Noninvasive ventilation (NIV) is a promising alternative to invasive mechanical ventilation (IMV) with a particular importance amidst the shortage of intensive care unit (ICU) beds during the COVID-19 pandemic. We aimed to evaluate the use of NIV in Europe and factors associated with outcomes of patients treated with NIV.

METHODS

This is a substudy of COVIP study-an international prospective observational study enrolling patients aged ≥ 70 years with confirmed COVID-19 treated in ICU. We enrolled patients in 156 ICUs across 15 European countries between March 2020 and April 2021.The primary endpoint was 30-day mortality.

RESULTS

Cohort included 3074 patients, most of whom were male (2197/3074, 71.4%) at the mean age of 75.7 years (SD 4.6). NIV frequency was 25.7% and varied from 1.1 to 62.0% between participating countries. Primary NIV failure, defined as need for endotracheal intubation or death within 30 days since ICU admission, occurred in 470/629 (74.7%) of patients. Factors associated with increased NIV failure risk were higher Sequential Organ Failure Assessment (SOFA) score (OR 3.73, 95% CI 2.36-5.90) and Clinical Frailty Scale (CFS) on admission (OR 1.46, 95% CI 1.06-2.00). Patients initially treated with NIV (n = 630) lived for 1.36 fewer days (95% CI - 2.27 to - 0.46 days) compared to primary IMV group (n = 1876).

CONCLUSIONS

Frequency of NIV use varies across European countries. Higher severity of illness and more severe frailty were associated with a risk of NIV failure among critically ill older adults with COVID-19. Primary IMV was associated with better outcomes than primary NIV. Clinical Trial Registration NCT04321265 , registered 19 March 2020, https://clinicaltrials.gov .

Brain monitoring in hospitals needs to be strengthened

Careful brain monitoring saves lives and is beneficial to patients' health. Nevertheless, Norway lacks guidelines for brain monitoring in hospitals.

Vaccine Induced Immune Thrombotic Thrombocytopenia Causing a Severe Form of Cerebral Venous Thrombosis With High Fatality Rate: A Case Series

During a 2-week period, we have encountered five cases presenting with the combination of cerebral venous thrombosis (CVT), intracerebral hemorrhage and thrombocytopenia. A clinical hallmark was the rapid and severe progression of disease in spite of maximum treatment efforts, resulting in fatal outcome in for 4 out of 5 patients. All cases had received ChAdOx1 nCov-19 vaccine 1–2 weeks earlier and developed a characteristic syndrome thereafter. The rapid progressive clinical course and high fatality rate of CVT in combination with thrombocytopenia in such a cluster and in otherwise healthy adults is a recent phenomenon. Cerebral autopsy findings were those of venous hemorrhagic infarctions and thrombi in dural venous sinuses, including thrombus material apparently rich in thrombocytes, leukocytes and fibrin. Vessel walls were free of inflammation. Extra-cerebral manifestations included leech-like thrombi in large veins, fibrin clots in small venules and scattered hemorrhages on skin and membranes. CVT with thrombocytopenia after adenovirus vectored COVID-19 vaccination is a new clinical syndrome that needs to be recognized by clinicians, is challenging to treat and seems associated with a high mortality rate.

Timelines and rebleeds in patients admitted into neurosurgical care for aneurysmal subarachnoid haemorrhage

Background

Mortality and morbidity of aneurysmal subarachnoid haemorrhage (aSAH) remain high, and prognosis is influenced by multiple non-modifiable factors such as aSAH severity. By analysing the chronology of aSAH management, we aim at identifying modifiable factors with emphasis on the occurrence of rebleeds in a setting with 24/7 surgical and endovascular availability of aneurysm repair and routine administration of tranexamic acid.

Methods

Retrospective analysis of institutional quality registry data of aSAH cases admitted into neurosurgical care during the time period 01 January 2013–31 December 2017. We registered time and mode of aneurysm repair, haemorrhage patterns, course of treatment, mortality and functional outcome. Rebleeding was scored along the entire timeline from ictus to discharge from the primary stay.

Results

We included 544 patients (368, 67.6% female), aged 58 ± 14 years (range 1–95 years). Aneurysm repair was performed in 486/544 (89.3%) patients at median 7.4 h after arrival and within 3, 6, 12 and 24 h in 26.8%, 44.7%, 73.0% and 96.1%, respectively. There were circadian variations in time to repair and in rebleeds. Rebleeding prior to aneurysm repair occurred in 9.7% and increased with aSAH severity and often in conjunction with patient relocations or interventions. Rebleeds occurred more often during surgical repair outside regular working hours, whereas rebleeds after repair (1.8%) were linked to endovascular repair.

Conclusions

The risk of rebleed is imminent throughout the entire timeline of aSAH management even with ultra-early aneurysm repair. Several modifiable factors can be linked to the occurrence of rebleeds and they should be identified and optimised within neurosurgical departments.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00701-020-04673-3.

Behavioral effects of sub-anesthetic ketamine in a go/no-go task

Background and aims

While psychedelic agents are known to have powerful, but largely unexplained, effects on contents of consciousness, there is an increasing interest in the potential clinical usefulness of such drugs for therapy, and legalization is discussed in some countries. Thus, it is relevant to study the effects of psychedelic compounds not only on experience, but also on behavioral performance.

Methods

Seven healthy participants performed a motor response inhibition task before, during, and after sub-anesthetic doses of intravenously administered ketamine. The infusion rate was individually adjusted to produce noticeable subjective psychedelic effects.

Results

We observed no statistically significant impact of sub-anesthetic ketamine on reaction times, omission errors, or post error slowing, relative to the preceding drug-free condition. However, we did observe significant correlations between performance impairment and self-reported, subjective altered states of consciousness, specifically experience of “anxiety” and “complex imagery.”

Conclusions

Considering the limited number of participants and large variation in strength of self-reported experiences, further studies with wider ranges of ketamine doses and behavioral tasks are needed to determine the presence and strength of potential behavioral effects.

An electrophysiological marker of arousal level in humans

Deep non-rapid eye movement sleep (NREM) and general anesthesia with propofol are prominent states of reduced arousal linked to the occurrence of synchronized oscillations in the electroencephalogram (EEG). Although rapid eye movement (REM) sleep is also associated with diminished arousal levels, it is characterized by a desynchronized, 'wake-like' EEG. This observation implies that reduced arousal states are not necessarily only defined by synchronous oscillatory activity. Using intracranial and surface EEG recordings in four independent data sets, we demonstrate that the 1/f spectral slope of the electrophysiological power spectrum, which reflects the non-oscillatory, scale-free component of neural activity, delineates wakefulness from propofol anesthesia, NREM and REM sleep. Critically, the spectral slope discriminates wakefulness from REM sleep solely based on the neurophysiological brain state. Taken together, our findings describe a common electrophysiological marker that tracks states of reduced arousal, including different sleep stages as well as anesthesia in humans.

Ultrasonographic needle tip tracking for in-plane infraclavicular brachialis plexus blocks: a randomized controlled volunteer study

BACKGROUND

Onvision is a new technology for needle tip detection and tracking in ultrasound-guided regional anesthesia. The system consists of a piezoelectric sensor close to the needle tip and an electronic console integrated in the ultrasound system. The needle tip is visualized by a green circle on the ultrasound screen. The aim of the study was to investigate the effect of the new needle tip tracking technology on in-plane infraclavicular plexus blocks.

METHODS

The study was a randomized, controlled, observer blinded cross-over trial in 26 healthy volunteers. Two specialists in anesthesiology performed an ultrasound-guided infraclavicular lateral sagittal brachial plexus block with and without needle tip tracking. Primary outcome was procedure time, measured from insertion of the needle until local anesthesia injection was completed. Secondary outcome measures included the number of hand movements and path lengths (assessed by hand motion analysis), block success rate, onset time and duration, discomfort experienced by the volunteers, and the anesthesiologists' confidence as to whether their block would be successful or not.

RESULTS

Mean (SD) procedure time was 183.0 (56.1) s with and 206.8 (56.2) s without needle tip tracking (p=0.16). There were no significant differences in any of the secondary outcomes. Two volunteers' experienced Horner syndrome after blocks without needle tip tracking. No other adverse events occurred during the study.

CONCLUSION

Our study on needle tip tracking for infraclavicular blocks did not reveal any significant differences between active needle tip tracking and the control procedures, neither for primary outcome nor secondary outcome measurements.

TRIAL REGISTRATION NUMBER

NCT03631914.

Needle tip tracking for ultrasound-guided peripheral nerve block procedures-An observer blinded, randomised, controlled, crossover study on a phantom model

BACKGROUND

The Onvision needle tip tracking (NTT) is a new technology consisting of a needle with an ultrasound sensor close to the needle tip and a console for computerised signal processing. The aim of the study was to evaluate NTT technology during ultrasound-guided simulated peripheral nerve block procedures in a porcine phantom model.

METHODS

Forty anaesthesiologists performed in-plane and out-of-plane simulated nerve blocks with and without NTT guidance. The primary outcome measure was procedure time. Secondary outcomes were hand movements and the path length travelled by the hands measured by motion analysis, precision of the needle tip related to the target structure, success rates and violations of the target structure, and the participants confidence whether their procedure would be successful or not.

RESULTS

Procedure time was reduced from 66.7 (SD = 47.5) seconds to 43.8 (SD = 29.2) seconds when NTT was used for out-of-plane procedures (P = 0.002). The number of hand movements of the probe hand was 13.9 (SD = 30.2) with NTT and 22.8 (SD = 30.0) without NTT (P = 0.019). No significant differences were registered during the performance of in-plane procedures. The participants confidence in a presumed block success was increased with both in-plane procedures (8.50 (SD = 1.18) with NTT vs 7.65 (SD = 1.96), P = 0.004) and out-of-plane procedures (8.50 (SD = 1.09) vs 7.10 (SD = 1.89), P = 0.0001).

CONCLUSIONS

The new NTT technology significantly reduced the procedure time and the number of hand movements for ultrasound-guided out-of-plane PNB procedures. No significant differences were found for the in-plane procedures.

Distinguishing Anesthetized from Awake State in Patients: A New Approach Using One Second Segments of Raw EEG

Objective: The objective of this study was to test whether properties of 1-s segments of spontaneous scalp EEG activity can be used to automatically distinguish the awake state from the anesthetized state in patients undergoing general propofol anesthesia.

Methods: Twenty five channel EEG was recorded from 10 patients undergoing general intravenous propofol anesthesia with remifentanil during anterior cervical discectomy and fusion. From this, we extracted properties of the EEG by applying the Directed Transfer Function (DTF) directly to every 1-s segment of the raw EEG signal. The extracted properties were used to develop a data-driven classification algorithm to categorize patients as “anesthetized” or “awake” for every 1-s segment of raw EEG.

Results: The properties of the EEG signal were significantly different in the awake and anesthetized states for at least 8 of the 25 channels (p < 0.05, Bonferroni corrected Wilcoxon rank-sum tests). Using these differences, our algorithms achieved classification accuracies of 95.9%.

Conclusion: Properties of the DTF calculated from 1-s segments of raw EEG can be used to reliably classify whether the patients undergoing general anesthesia with propofol and remifentanil were awake or anesthetized.

Significance: This method may be useful for developing automatic real-time monitors of anesthesia.

Pregabalin reduces opioid consumption and hyperalgesia but not pain intensity after laparoscopic donor nephrectomy

BACKGROUND

Gabapentinoids are increasingly used to reduce acute postoperative pain, opioid consumption and opioid-related adverse effects. We explored the opioid-sparing, analgesic and anti-hyperalgesic effect of perioperative administered pregabalin in laparoscopic living donor nephrectomy.

METHODS

In this randomized controlled trial, 80 patients were recruited and randomized to receive pregabalin 150 mg twice daily or placebo on the day of surgery and the first postoperative day as part of a multimodal analgesic regimen. Primary outcome was opioid consumption 0-48 h after surgery. Secondary outcomes were pain intensity at rest and with movement 0-48 h after surgery using the 0-10 Numeric Rating Scale and incisional hyperalgesia measured 24 h post-surgery and at hospital discharge. Further secondary outcomes were adverse effects. Persistent post-surgical pain was registered 6 weeks, 6 and 12 months after surgery.

RESULTS

Pregabalin significantly reduced opioid consumption compared with placebo 0-48 h after surgery (median mg [25th, 75th percentile]); 29.0 (22.0-45.5) vs. 41.8 (25.8-63.6) (P = 0.04). Pain intensity 0-48 h after surgery calculated as area under the pain (NRS) vs. time curve was not statistically different between groups at rest (P = 0.12) or with movement (P = 0.21). Pregabalin decreased incisional hyperalgesia 24 h after surgery (median cm [25th, 75th percentile] 8.5 (1.0-18.5) vs. 15.5 (9.5-24.0) (P = 0.02). Nausea (P ≤ 0.01), use of antiemetics (P ≤ 0.01) and pain-related sleep interference (P = 0.02) were reduced with pregabalin.

CONCLUSIONS

Perioperative pregabalin added to a multimodal analgesic regimen was opioid-sparing, but made no difference to pain intensity score 0-48 h after surgery. Pregabalin may reduce incisional hyperalgesia on the first day after surgery.

Chronic pain after breast augmentation is associated with both signs of peripheral nerve injury and central nervous mechanisms

Background/aims

The mechanisms behind chronic postsurgical pain remains unsettled. Quantitative sensory testing and questioning sensory function may help understand mechanisms behind the transition from acute to chronic pain. The aim of this study was to assess these aspects in postsurgical patients with and without chronic postsurgical pain.

Methods

116 women, who answered a questionnaire in a four years follow-up study of pain, sensory changes and quality of life after cosmetic breast augmentation surgery [1], were invited to participate in a psychophysical study. Twenty women answered the request and filled in a questionnaire, and 12 of these women finally met for examination.

Results

Six of the 12 women had pain in the area of surgery, three were pain-free, but reported sensory changes and three reported no pain or sensory disturbances. We performed a detailed quantitative sensory examination, with a protocol adapted from Rollke et al. [2] While only 3/6 patients in the pain-free group reported hypoesthesia, an area of hypoesthesia to tactile-, heat- and cold stimuli was identified in all subjects when examined (Table 1).

Table 1

The most striking difference between the group reporting pain and the one not reporting pain was the presence of paradoxical heat sensation, cold allodynia, abnormal temporal summation, and the presence of deep pain during/after pressure pain threshold testing with the algometer in the group with pain.

Conclusion

Self-reported sensory changes under-estimated sensory changes. Sensory testing revealed signs of peripheral nerve injury changes in all subjects, while signs of central nervous changes were found predominantly in patients with persistent pain.

Challenges of Major Incident Management When Excess Resources are Allocated: Experiences from a Mass Casualty Incident after Roof Collapse of a Military Command Center

During a military exercise in northern Norway in March 2000, the snowladen roof of a command center collapsed with 76 persons inside. Twentyfive persons were entrapped and/or buried under snow masses. There were three deaths. Seven patients had serious injuries, three had moderate injuries, and 16 had minor injuries.

A military Convalescence Camp that had been set up in a Sports Hall 125 meters from the scene was reorganized as a causality clearing station. Officers from the Convalescence Camp initially organized search and rescue. In all, 417 persons took part in the rescue work with 36 ambulances, 17 helicopters, three ambulance airplanes and one transport plane available. Two ambulances, five helicopters and one transport aircraft were used. Four patients were evacuated to a civilian hospital and six to a field hospital.

The stretcher and treatment teams initially could have been more effectively organized. As resources were ample, this was a mass casualty, not a disaster. Firm incident command prevented the influx of excess resources.

Persistent postsurgical pain in a general population: prevalence and predictors in the Tromsø study

Population-based data on the prevalence of persistent postsurgical pain are scarce. This study aimed to assess the prevalence of persistent postsurgical pain in a general population and to describe associated physical, social, and psychological factors, including symptoms of nerve injury and sensitization. A cross-sectional survey was performed in northern Norway with questionnaire items covering surgery, pain, and sensory abnormalities in the area of surgery. Of the 12,982 participants, 24.0% (3111) had undergone one or more surgical procedures during the 3 years preceding the survey. Of these, 2043 had the surgery performed more than 3 months before the investigation. Persistent pain in the area of surgery was reported by 40.4% of the patients (826 of 2043), moderate or severe pain by 18.3% (373 of 2043). Hypoesthesia, hyperesthesia, or both was reported by 24.5% (501 of 2043). There were strong associations between sensory abnormalities and persistent pain, increasingly with higher pain intensities; odds ratios were 2.68 for hypoesthesia and 6.27 for hyperesthesia. Of the 826 individuals reporting persistent pain in the anatomical area of surgery, 51.0% reported chronic pain when questioned without specific reference to the surgery. The present study supports evidence from clinical studies of persistent postsurgical pain, indicating a high prevalence, but reveals large discrepancies in report of pain, depending on the questions asked and the context in which the questions are presented. Strong associations between sensory abnormalities and pain indicate neuropathic mechanisms in a major proportion of cases.

Adding propacetamol to ketorolac increases the tolerance to painful pressure

Combining an NSAID and paracetamol (acetaminophen) has in some studies given superior analgesia compared with the single drugs. In other trials no additive effect has been found. We have investigated the effect of this drug combination on the pressure pain tolerance threshold (PPTT), a reproducible correlate to clinical pain. The aim of this double blind, randomised, placebo controlled, crossover study was to evaluate the effect of i.v. propacetamol 2 g (= paracetamol 1 g) and ketorolac 30 mg, individually and in combination, on PPTT in 16 volunteers on four separate days. PPTT was measured 15 min before and at 45, 60, 90 and 150 min after the start of test drug administration. The pressure stimuli were applied on the base of a fingernail, increasing by 30 kPa/s until the pressure pain tolerance threshold was reached. For the total observation period (150 min), only the combination (propacetamol+ketorolac) increased significantly PPTT compared with baseline (P<0.04), while PPTT decreased significantly after placebo (P<0.01). The combination (propacetamol+ketorolac) and ketorolac alone increased PPTT compared with placebo (combination vs. placebo and ketorolac vs. placebo, P<0.001) and with propacetamol (combination vs. propacetamol and ketorolac vs. propacetamol, P<0.001). The combination was significantly better than ketorolac alone (P<0.04). After propacetamol 2 g, PPTT did not change significantly neither compared with placebo or baseline.

CONCLUSIONS

Tolerance to repeated painful pressure (PPTT) decreased after placebo. Ketorolac 30 mg caused an increase in PPTT compared with placebo but not with baseline. Adding propacetamol 2 g to ketorolac 30 mg significantly increased PPTT. These findings support the practice of combining paracetamol with an NSAID for relief of acute pain.

Epidemiology of persistent postoperative pain: Association of persistent pain and sensory abnormalities

Background

The prevalence of persistent postoperative pain in the general population is poorly documented, but clinical studies indicate that the problem is common.

Aim

The aim of this study was (1) to assess the prevalence of persistent postoperative pain among individuals operated during the last 3 years in a general population and (2) to describe factors associated with chronic postoperative pain.

Materials and methods

As part of a cross-sectional health survey in the municipality of Tromsø, North Norway, all participants answered questions on surgery, persisting pain and sensory abnormalities in the area of surgery. N = 12,984. Age 30–87 years, median 59. 53.4% women.

Pain intensity was reported using a 0–10 Numeric Rating Scale (0–10 NRS). Logistic regression was used to reveal any associations between pain and self-reported hyposensitivity, hypersensitivity and allodynia.

Results

2316 individuals (17.8%) had surgery between 3 months and 3 years prior to the survey.

826 (40.4%)of the 2044 who answered a questionnaire on postsurgical pain, reported having some degree of pain in the area of surgery. Of these 826 individuals, 45.2% had pain, when at worst, of moderate or severe intensity, i.e. 0–10 NRS of 4 or higher.

The areas of surgery carrying the strongest association with persistent pain were (in descending order of frequency): (1) Shoulder/ upper arm [74.5% (108/145)], (2) back [73.9% (65/88)], (3) lungs [66.7% (8/12)], (4) knee/lower leg [63.7% (179/281)], (5) hand [58.8% (90/153)]. (6) hip/thigh [58.3% (74/127)] and (7) ankle/foot [58.7% (84/143)].

18.3% (413) had reduced sensitivity in the area near the surgical scar, while 10.6% (240) reported hypersensitivity and 5.6% (127) allodynia.

For those reporting hypoesthesia, the odds ratio (OR) for having pain was 2.71 (95% confidence interval 2.08–3.53), for those reporting hyperesthesia, OR was 4.82 (3.24–7.18) and for those with allodynia 5.83 (3.12–10.90).

Conclusions

3 months or more after surgery, nearly half of the respondents report having pain in the area of surgery. In this survey, there is a strong association between persistent pain and the presence of both hyposensitivity, hypersensitivity and allodynia.

Hyperesthesia one year after breast augmentation surgery increases the odds for persisting pain at four years A prospective four-year follow-up study

In this long-term follow-up study of 175 women, we investigated the prevalence of and factors associated with persisting pain and sensory changes four years after augmentation mammoplasty. Previously the women had participated in an acute postoperative pain study, and follow-up investigations at 6 weeks and 1 year after surgery. In the present study, the women were mailed questionnaires about pain, sensory changes, and affection of daily life, quality of life and pain catastrophizing 4 years after surgery.

One hundred and sixteen women answered the questionnaire. The fraction of women reporting evoked- and/or spontaneous pain during the last 24 h had declined from 20% at 1 year to 14% at 4 years. Hyperesthesia had declined from 46% at 1 year to 32% at 4 years, while the change in hypoesthesia was small, 47% at 1 year to 51% at 4 years. Methylprednisolone and parecoxib given pre incisionally reduced acute postoperative pain and reduced the prevalence of hyperesthesia after 6 weeks/1 year, but after 4 years we found no significant differences between the test drug groups. Those having concomitant pain and hyperesthesia at 6 weeks and 1 year had high odds for persisting pain at 4 years (OR 7.8, 95% CI 2.1–29.8, P = 0.003; OR 13.2, 95% CI 2.5–71.3, P = 0.003). In patients without pain but with hyperesthesia at 1 year, the hyperesthesia increased the odds for pain at 4 years (OR 2.6 95% CI 1.1–6.1, P = 0.03). Hypoesthesia at 6 weeks or at 1 year did not affect the odds for pain at 4 years. A good general health condition (mental and physical) was associated with reduced odds for pain at 4 years (OR = 0.56, 95% CI 0.35–0.88, P = 0.01). However, using the Short Form health survey, SF-12, the Mental Component Summary Score seemed to affect the odds for chronic pain more than the Physical Component Summary Score.

To conclude, the prevalence of pain and hyperesthesia after breast augmentation declined from 1 to 4 years. Nevertheless, the most striking finding in the current trial was that pain coinciding with hyperesthesia at 6 weeks and 1 year resulted in highly increased odds for persistent postoperative pain. Even hyperesthesia alone, without pain, increased the odds for chronic postsurgical pain. Thus, the present study suggests hyperesthesia as an independent risk factor for chronic postsurgical pain.

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.

Methylprednisolone and ketorolac rapidly reduce hyperalgesia around a skin burn injury and increase pressure pain thresholds

BACKGROUND

Glucocorticoids and non-steroidal anti-inflammatory drugs (NSAIDs) decrease acute postoperative pain and hyperalgesia. The objectives of this study were to investigate the effects of methylprednisolone and ketorolac on hyperalgesia around a skin burn injury and on pressure pain thresholds.

METHODS

In a double-blind, placebo-controlled, randomized trial with cross-over design, methylprednisolone 125 mg, ketorolac 60 mg or placebo was administered intravenously in 12 male volunteers on three separate days at least 4 days apart. Primary and secondary hyperalgesia were produced by a first-degree burn injury on abdominal skin 45 min before injection of the test medicines. The area of secondary mechanical hyperalgesia outside the site of injury was measured. Pressure pain stimuli were applied on the base of a fingernail, increasing until the pressure pain detection threshold (PPDT) and pressure pain tolerance threshold (PPTT) were reached.

RESULTS

Compared with placebo, the active drugs reduced the area of secondary hyperalgesia (methylprednisolone, P < 0.001; ketorolac, P < 0.01). Ketorolac but not methylprednisolone increased PPDT compared with placebo (P < 0.05). Both active drugs increased PPTT compared with placebo (methylprednisolone, P < 0.01; ketorolac, P < 0.001). Ketorolac increased PPTT more than methylprednisolone (P < 0.05).

CONCLUSIONS

Methylprednisolone and ketorolac increased PPTT attenuated secondary hyperalgesia around a skin burn injury. PPTT increased after both methylprednisolone and ketorolac. The present study demonstrates analgesic and anti-hyperalgesic properties of a glucocorticoid and a non-selective NSAID that have not been demonstrated previously in human subjects.

Chronic pain and sensory changes after augmentation mammoplasty: Long term effects of preincisional administration of methylprednisolone

We studied the prevalence of chronic pain and long term sensory changes after cosmetic augmentation mammoplasty and the effects of a single i.v. preoperative dose of methylprednisolone 125 mg (n=74), parecoxib 40 mg (n=71), or placebo (n=74). A questionnaire was mailed 6 weeks and 1 year after surgery. Response rate after 1 year was 80%. At 1 year non-evoked pain was present in 13%, and evoked pain was present in 20% with no statistically significant differences between the groups. Methylprednisolone was associated with reduced odds for hyperesthesia at 1 year (OR 0.3, 95% CI 0.1-0.6), and significantly reduced the prevalence of hyperesthesia (30%) compared with placebo (56%, P<0.01) and parecoxib (51%, P<0.04). Factors associated with increased odds for pain at 1 year were intensity of pain during the first 6 days after surgery (OR 1.3, 95% CI 1.1-1.6), pain at 6 weeks (OR 18.4, 95% CI 6.9-49.3), hyperesthesia at 6 weeks (OR 2.3, 95% CI 1.1-5.1) and present hyperesthesia (OR 3.1, 95% CI 1.4-6.7). We conclude that persistent pain and sensory changes are common after augmentation mammoplasty, and that patients having pain at 6 weeks most likely will have pain also at 1 year. Acute postoperative pain, hyperesthesia at 6 weeks, and the presence of hyperesthesia increased the odds for pain at 1 year. Preoperative methylprednisolone resulted in significantly less hyperesthesia compared with both parecoxib and placebo, but did not significantly reduce the prevalence of persistent spontaneous or evoked pain.

Methylprednisolone reduces pain, emesis, and fatigue after breast augmentation surgery: a single-dose, randomized, parallel-group study with methylprednisolone 125 mg, parecoxib 40 mg, and placebo

We compared methylprednisolone 125 mg IV (n = 68) and parecoxib 40 mg IV (n = 68) with placebo (n = 68) given before breast augmentation surgery in a randomized, double-blind parallel group study. Surgery was performed under local anesthesia combined with propofol/fentanyl sedation. Methylprednisolone and parecoxib decreased pain at rest and dynamic pain intensity from 1 to 6 h after surgery compared with placebo (mean summed pain intensity(1-6 h): methylprednisolone [17.25; 95% confidence interval [CI], 14.85-19.65] versus placebo [21.7; 95% CI, 19.3-24.1]; P < 0.03; parecoxib [15.25; 95% CI, 13.25-17.25] versus placebo; P < 0.001; mean summed dynamic pain intensity(1-6 h): methylprednisolone [22.7; 95% CI, 20.1-23.3] versus placebo [28.4; 95% CI, 26.0-30.8]; P < 0.01; parecoxib [20.9; 95% CI, 18.6-23.2] versus placebo; P < 0.001). Both rescue drug consumption and actual pain (all observations before and after rescue) during the first 6 h were similar in the two active drug groups and significantly reduced compared with placebo. Using a composite score of actual pain intensity and rescue analgesic use, the active drugs were significantly superior to placebo (P < 0.001 for both active drugs). Postoperative nausea and vomiting was reduced after methylprednisolone administration (incidence, 30%), but not after parecoxib (incidence, 37%), during the first 24 h compared with placebo (incidence, 60%; P < 0.001). Fatigue was reduced by methylprednisolone (incidence, 44%), but not by parecoxib (incidence, 59%), compared with placebo (incidence, 66%; P < 0.05). In conclusion, methylprednisolone 125 mg IV given before breast augmentation surgery had analgesic and rescue analgesic-sparing effects comparable with those of parecoxib 40 mg IV. Methylprednisolone, but not parecoxib, reduced nausea, vomiting, and fatigue.

[Glucocorticoids reduce acute postoperative pain]

Glucocorticoids have been used for postsurgical pain relief over the last 30 years. They reduce prostaglandins by inhibiting phospholipase A2 and the expression of COX-2 mRNA. The evidence for an analgesic effect is best after oral, orthopaedic, laparoscopic and perianal surgery. Their anti-emetic properties in addition to the analgesic effects make them particularly useful perioperatively.

Methylprednisolone intravenously 1 day after surgery has sustained analgesic and opioid-sparing effects

BACKGROUND

In previous studies on glucocorticoids for postoperative pain, the test drug has been given perioperatively, usually before measurement of baseline pain. In order to evaluate the time course and magnitude of the analgesic effect of a glucocorticoid in well-established postoperative pain, we compared methylprednisolone with ketorolac and placebo, after assessment of baseline pain on the first postoperative day.

METHODS

This was a double-blind, single dose, randomized, parallel comparison of intravenous (i.v.) methylprednisolone 125 mg, ketorolac 30 mg as an active control, and placebo in 75 patients with moderate to severe pain 1 day after orthopaedic surgery. Outcome variables were pain intensity (0-100 VAS), pain relief (0-4 PAR) and rescue opioid consumption.

RESULTS

Methylprednisolone was not significantly different from ketorolac and gave significantly lower pain intensity from 1 h (0-6 h, P < 0.02), and more pain relief 2-6 h after test drugs (P < 0.05) compared with placebo. After 24 h, pain intensity was lower in both active drug groups compared with placebo (methylprednisolone, P < 0.0001; ketorolac, P < 0.007). Number needed to treat (NNT) calculated from patients having more than at least 50% of maximum obtainable total pain relief during the first 6 h (>50%maxTOTPAR(6 h)) was 3.6 for methylprednisolone and 3.1 for ketorolac. Number needed to treat calculated from the percentage reporting at least 50% pain relief for at least 4 h (>50%PAR(4 h)) was 2.8 for both groups. Opioid consumption was significantly reduced for 72 h after methylprednisolone compared with ketorolac (P < 0.02) and placebo (P < 0.003).

CONCLUSION

Methylprednisolone 125 mg i.v. 1 day after surgery gave similar early reduction of pain as i.v. ketorolac 30 mg. Less pain than placebo 24 h after methylprednisolone, and lower opioid consumption for 72 h compared with ketorolac and placebo indicate sustained analgesic effects of methylprednisolone.

Trauma team training in a distributed virtual emergency room

A distributed simulation environment for training and evaluation of medical trauma teams is presented. Connected through the Internet, the geographically remote team members can communicate and interact using the clinically realistic environment provided by the MATADOR simulator. The scenario demonstrates an injured person's arrival at the hospital, and the diagnostic and therapeutic challenges that must be met in order to stabilize the virtual patient. Experiences from a field trial indicate that the simulator is useful both for professionals and medical students.