[Critical incidents in acute pain management-A risk analysis of CIRS reports]. / Kritische Ereignisse in der Akutschmerztherapie ­ eine Risikoanalyse von CIRS-Meldungen.

BACKGROUND: Areas of activity with many intersections pose an increased risk for errors and critical incidents. Therefore, procedures for acute pain therapy are potentially associated with an increased risk for adverse patient outcomes. OBJECTIVE: The aim was to identify and grade the risk of critical incidents in the context of acute pain management. MATERIAL AND METHODS: The register of the nationwide reporting system critical incident reporting system of the Professional Association of German Anesthesiologists, the German Society for Anesthesiology and Intensive Care Medicine and the Medical Center for Quality in Medicine (CIRSmedical Anesthesiology) was screened for incidents concerning pain management. Out of 5365 cases reported nationwide up to 24 March 2020, 508 reports with the selection criterion "pain" could be identified and reviewed and 281 reports (55%) were included in a systematic analysis. RESULTS: Of the 281 reports most came from anesthesiology departments (94%; 3% from surgery departments and 3% from other departments). The reported cases occurred most frequently on normal wards but a relevant proportion of the reports concerned intermediate and intensive care units or areas covered by a pain service (PS). Based on the description of the incident in the report, an involvement of the PS could be assumed for 42% of the cases. In terms of time, most of the events could be assigned to normal working hours (90%) and working days (84%; weekends 16%). The analyzed reports related to parenteral administration of analgesics (40%) and central (40%) or peripheral regional anesthesia procedures (23%) and 13% of the reports related to patient-controlled intravenous analgesia (PCIA; multiple answers possible). Most of the events were caused by technical errors, communication deficits and deviations from routine protocols. A relevant number of the cases were based on mix-ups in the administration route, the dosage, or the active agent. About one third of the sources of error were of an organizational nature, 59% of the cases posed a possible vital risk and in 16% of cases patients had vital complications. The risk grading by risk matrix resulted in an extremely high risk in 7%, a high risk in 62%, a moderate risk in 25% and a low risk in 6% of the cases. Comparing risk assessment of events with involvement of different analgesic methods, multiple medication, combination of analgesic methods or involvement of PS showed no significant differences. Likewise, no differences could be identified between the risk assessments of events at different superordinate cause levels. If more than one overriding cause of error had an impact, initially no higher risk profile was found. CONCLUSION: Incidents in the context of acute pain management can pose high risks for patients. Incidents or near-incidents are mostly related to mistakes and lack of skills of the staff, often due to time pressure and workload as well as to inadequate organization.

Quality of pain treatment after caesarean section: Results of a multicentre cohort study.

BACKGROUND: A large cohort study recently reported high pain scores after caesarean section (CS). The aim of this study was to analyse how pain after CS interferes with patients' activities and to identify possible causes of insufficient pain treatment. METHODS: We analysed pain scores, pain-related interferences (with movement, deep breathing, mood and sleep), analgesic techniques, analgesic consumption, adverse effects and the wish to have received more analgesics during the first 24 h after surgery. To better evaluate the severity of impairment by pain, the results of CS patients were compared with those of patients undergoing hysterectomy. RESULTS: CS patients (n = 811) were compared with patients undergoing abdominal, laparoscopic-assisted vaginal or vaginal hysterectomy (n = 2406, from 54 hospitals). Pain intensity, wish for more analgesics and most interference outcomes were significantly worse after CS compared with hysterectomies. CS patients with spinal or general anaesthesia and without patient-controlled analgesia (PCA) received significantly less opioids on the ward (62% without any opioid) compared with patients with PCA (p < 0.001). Patients with PCA reported pain-related interference with movement and deep breathing between 49% and 52% compared with patients without PCA (between 68% and 73%; p-values between 0.004 and 0.013; not statistically significant after correction for multiple testing). CONCLUSION: In daily clinical practice, pain after CS is much higher than previously thought. Pain management was insufficient compared with patients undergoing hysterectomy. Unfavourable outcome was mainly associated with low opioid administration after CS. Contradictory pain treatment guidelines for patients undergoing CS and for breastfeeding mothers might contribute to reluctance of opioid administration in CS patients.

[Transition from acute to chronic postsurgical pain. Physiology, risk factors and prevention]. / Chronifizierung postoperativer Schmerzen. Physiologie, Risikofaktoren und Prävention.

Chronic postsurgical pain (CPSP) is defined as pain persisting for longer than 3 months postoperatively. The frequency of occurrence ranges from 5 % to 60 % in all types of surgery and 1-3 % of patients with CPSP will suffer from severe pain and pain-related interference with daily activities. The pathological mechanisms which lead to the development of CPSP are complex and have not yet been analyzed. Neuropathic pain after surgical nerve lesions has been reported. Many patients with CPSP, however, do not present with any neuropathic pain characteristics. Peripheral and central sensitization are the essential mechanisms of the development of pain chronicity in the postoperative period. As treatment of CPSP is demanding it is attempted to prevent central sensitization before CPSP develops. New scientific findings on the development of CPSP, perioperative risk factors and the potential of preventative interventions are discussed.

Determination of moderate-to-severe postoperative pain on the numeric rating scale: a cut-off point analysis applying four different methods.

BACKGROUND: Cut-off points (CPs) of the numeric rating scale (NRS 0-10) are regularly used in postoperative pain treatment. However, there is insufficient evidence to identify the optimal CP between mild and moderate pain. METHODS: A total of 435 patients undergoing general, trauma, or oral and maxillofacial surgery were studied. To determine the optimal CP for pain treatment, four approaches were used: first, patients estimated their tolerable postoperative pain intensity before operation; secondly, 24 h after surgery, they indicated if they would have preferred to receive more analgesics; thirdly, satisfaction with pain treatment was analysed, and fourthly, multivariate analysis was used to calculate the optimal CP for pain intensities in relation to pain-related interference with movement, breathing, sleep, and mood. RESULTS: The estimated tolerable postoperative pain before operation was median (range) NRS 4.0 (0-10). Patients who would have liked more analgesics reported significantly higher average pain since surgery [median NRS 5.0 (0-9)] compared with those without this request [NRS 3.0 (0-8)]. Patients satisfied with pain treatment reported an average pain intensity of median NRS 3.0 (0-8) compared with less satisfied patients with NRS 5.0 (2-9). Analysis of average postoperative pain in relation to pain-related interference with mood and activity indicated pain categories of NRS 0-2, mild; 3-4, moderate; and 5-10, severe pain. CONCLUSIONS: Three of the four methods identified a treatment threshold of average pain of NRS≥4. This was considered to identify patients with pain of moderate-to-severe intensity. This cut-off was indentified as the tolerable pain threshold.

[Impact of preoperative pain on postoperative pain chronification. Six-month follow-up after urologic surgery]. / Einfluss präoperativer Schmerzen auf die postoperative Schmerzchronifizierung. Sechs Monate Nachbeobachtung nach urologischen Operationen.

BACKGROUND: We examined the influence of preoperative pain on postoperative pain chronification in urological patients. METHODS: Pain was determined before operation, immediately afterwards and 3 or 6 months post-surgically. Acute and chronic pain was analysed in detail with regard to severity, grade of chronification and pain intensity. We also assessed patients with the Hospital Anxiety and Depression Scale. RESULTS: Patients with preoperative pain reported postoperatively higher pain scores compared to patients without preoperative pain. Patients with higher Hospital Anxiety and Depression Scale scores reported higher pain scores for the first 7 days after the operation. Three months after surgery 51.2% of all patients and 6 months after surgery 1.2% of all patients reported about pain. CONCLUSION: Our results give evidence to the fact that preexisting pain prior to surgery has an influence on the postoperative pain course. To avoid chronification adequate therapy of the preexisting pain should be carried out.

Effects of thiopental on endothelium-dependent relaxation in porcine coronary arteries.

This study investigated the effects of thiopental on endothelium-dependent relaxation (EDR), and especially the effects on nitric oxide- and prostacyclin-independent EDR. Fresh porcine coronary artery rings (4 mm long), were consecutively tested with and without 20 microg/ml thiopental in Krebs-Henseleit solution. Indomethacin (10 micromol/l) was used in all experiments to eliminate prostacyclin effects. Prostaglandin F(2alpha) (10 micromol/l) was used to induce contractions and bradykinin (10(-10) - 10(-5) M) was used to induce EDR. Experiments were also carried out using 300 micromol/l N-nitro-L-arginine to block nitric oxide production and to assess the influence of thiopental on nitric oxide- and prostacyclin-independent EDR. Thiopental induced statistically significant increases in EDR at concentrations of 10(-6) - 10(-5) M bradykinin. Following nitric oxide production block, thiopental significantly reduced the relaxation response at concentrations of 10(-8) - 10(-5) M bradykinin. At a clinically relevant concentration of 20 microg/ml thiopental, a significant increase in EDR and a significant reduction in nitric oxide- and prostacyclin-independent relaxation was observed in porcine epicardial coronary arteries.

[Postoperative pain therapy after radical prostatectomy with and without epidural analgesia]. / Postoperative Schmerztherapie nach radikaler Prostatektomie mit oder ohne epiduraler Analgesie.

Epidural analgesia for postoperative pain treatment is favored, for example, within the scope of so-called fast-track surgery, especially abdominal surgery. To improve pain care for our urological patients, we examined the quality of postoperative pain therapy with and without epidural analgesia after radical prostatectomy. After the investigation was approved by the local ethics committee, patients were questioned in detail about the pain they experienced for 7 days after radical prostatectomy. For all 7 postoperative observation days, significantly less pain was measured for patients receiving epidural analgesia compared with patients without epidural analgesia. This could be shown for the average and strongest pain intensity at rest as well as for pain during mobilization. Patients with epidural analgesia were discharged, on average, 1 day earlier. After radical prostatectomy, postoperative pain therapy with epidural analgesia seems to offer advantages with regard to the quality of analgesia and the average length of hospital stay.

[Preoperative pain in urological patients scheduled for surgical intervention : Incidence, severity and chronicity]. / Präoperative Schmerzen bei urologisch operativen Patienten : Häufigkeit, Intensität und Chronizität.

BACKGROUND: The genesis of chronic pain in urology has so far been insufficiently investigated. No investigations have focused on the occurrence of preoperative pain. We developed an epidemiological questionnaire to analyze preoperative pain. METHODS: In this questionnaire, preoperative pain in all patients scheduled for urologic surgery (n=165) was analyzed. Acute and chronic pain was analyzed as main or adjoint pain, with the registration of severity, chronification states, and duration. We registered depression and anxiety, well-being, and somatic and psychological efficiency. RESULTS: Eighty percent of the patients reported pain within the previous 12 months. Acute preoperative pain was reported by 17% of the patients and chronic pain by 64%. Significant differences in quality of life were detected between patients with or without preoperative pain. Well-being was also significantly affected in patients having pain. CONCLUSION: The pain severity and states of chronification not only explain a reduction in somatic and psychological well-being but also emphasize that preoperative pain should be identified thoroughly prior to surgery.

[Influence of changes to daily dose of opioids on aspects of cognitive and psychomotor performance involved in driving]. / Einfluss von Anderungen der Opioidtagesdosis auf fahrrelevante kognitive und psychomotorische Leistungen.

INTRODUCTION: It has been shown that long-term treatment with opioids does not necessarily impair driving ability in patients suffering from chronic pain. However, few studies are so far available on how increases in daily opioid dosage affect driving ability. METHODS: A prospective trial was conducted in patients suffering from chronic noncancer pain, to examine the effects of the daily dose of opioids on psychomotor and cognitive functions. A computerized test system was administered to patients before and 7 days after alteration of their opioid therapy, to determine performance affecting driving ability at each time point. The test design was based on both international and national recommendations for the examination of driving safety. RESULTS: Raising the daily dose of opioids and/or changing to an opioid at a higher WHO level had no effect on the functions relevant to driving ability in the group context. Pain intensity and serum concentrations of morphine influenced only few items in the test battery. CONCLUSION: Seven days after an increase in the daily dose of an opioid or after the initiation of opioid therapy there was no general deterioration in patients' driving ability at group level.

[Measuring pressure pain thresholds. Comparison of an electromechanically controlled algometer with established methods]. / Messung der Druckschmerzempfindlichkeit. Vergleich eines elektromechanisch gesteuerten Algometers mit etablierten Methoden.

BACKGROUND: Measurement of the pressure pain threshold and suprathreshold pressure pain sensitivity using a newly developed computer controlled algometer was compared to established methods in this pilot study. METHODS: The pressure pain threshold was measured in 64 chronic pain patients and 37 healthy volunteers with a manual electronic algometer (Somedic) and the computer controlled Algoforce PA3. Stimulus-response curves with painful stimuli were applied using the Algoforce PA3 and a hydraulic algometer. RESULTS: Overall means and variance of the pressure pain thresholds for both methods were similar. For low pain thresholds the Algoforce PA3 generally resulted in lower values and for high pain thresholds in higher values. No differences were seen for suprathreshold pain sensitivity. Gender and the presence of chronic pain had no relevant effect on the different methods in both comparisons. CONCLUSION: For clinical use, the algometers investigated deliver comparable results. For studies requiring high precision with low levels of stimulation the use of the Algoforce PA3 could be considered.

[Central pain processing in chronic low back pain. Evidence for reduced pain inhibition]. / Zentrale Schmerzverarbeitung bei chronischem Rückenschmerz. Hinweise auf verminderte Schmerzinhibition.

INTRODUCTION: A study of patients with low back pain (LBP) had revealed altered central pain processing. At an equal pain level LBP patients had considerably more neuronal activation in the somatosensory cortices than controls. In a new analysis of this dataset, we further investigated the differences in central pain processing between LBP patients and controls, looking for possible pathogenic mechanisms. METHODS: Central pain processing was studied by functional magnetic resonance imaging (fMRI), using equally painful pressure stimuli in a block paradigm. In this study, we reanalyzed the fMRI data to statistically compare pain-elicited neuronal activation of both groups. RESULTS: Equally painful pressure stimulation resulted in a significantly lower increase of regional cerebral blood flow (rCBF) in the periaqueductal gray (PAG) of the LBP patients. The analysis further revealed a significantly higher increase of rCBF in LBP than in HC in the primary and secondary somatosensory cortex and the lateral orbitofrontal cortex (LOFK), elicited by these same stimuli. CONCLUSIONS: These findings support a dysfunction of the inhibitory systems controlled by the PAG as a possible pathogenic mechanism in chronic low back pain.

Propofol attenuates responses of the auditory cortex to acoustic stimulation in a dose-dependent manner: a FMRI study.

BACKGROUND: Functional magnetic resonance imaging (fMRI) using blood-oxygen-level-dependent (BOLD) contrasts is a common method for studying sensory or cognitive brain functions. The aim of the present study was to assess the effect of the intravenous anaesthetic propofol on auditory-induced brain activation using BOLD contrast fMRI. METHODS: In eight neurosurgical patients, musical stimuli were presented binaurally in a block design. Imaging was performed under five conditions: no propofol (or wakefulness) and propofol plasma target concentrations of 0.5, 1.0, 1.5, and 2.0 microg ml(-1). RESULTS: During wakefulness we found activations in the superior temporal gyrus (STG) corresponding to the primary and secondary auditory cortex as well as in regions of higher functions of auditory information processing. The BOLD response decreased with increasing concentrations of propofol but remained partially preserved in areas of basic auditory processing in the STG during propofol 2.0 microg ml(-1). CONCLUSIONS: Our results suggest a dose-dependent impairment of central processing of auditory information after propofol administration. These results are consistent with electrophysiological findings measuring neuronal activity directly, thus suggesting a dose-dependent impairment of central processing of auditory information after propofol administration. However, propofol did not totally blunt primary cortical responses to acoustic stimulation, indicating that patients may process auditory information under general anaesthesia.