A physiological model of phrenic nerve excitation by electrical stimulation.

Mechanical ventilation is essential in intensive care treatment but leads to diaphragmatic atrophy, which in turn contributes to prolonged weaning and increased mortality. One approach to prevent diaphragmatic atrophy while achieving pulmonary ventilation is electrical stimulation of the phrenic nerve. To automize phrenic nerve stimulation resulting in lung protective tidal volumes with lowest possible currents, mathematical models are required. Nerve stimulation models are often complex, so many parameters have to be identified prior to implementation. This paper presents a novel, simplified approach to model phrenic nerve excitation to obtain an individualized patient model using a few data points. The latter is based on the idea that nerve fibers are excited when the electric field exceeds a threshold. The effect of the geometry parameter on the model output was analyzed, and the model was validated with measurement data from a pig trial (RMSE in between 0.44 × 10-2and 1.64 × 10-2for parameterized models). The modeled phrenic nerve excitation behaved similarly to the measured tidal volumes, and thus could be used to develop automated phrenic nerve stimulation systems for lung protective ventilation.

Analgesia after tonsillectomy with controlled intravenous morphine - overdue or exaggerated?

OBJECTIVE: To assess the value of a morphine Patient Controlled Intravenous Analgesia (PCIA) after Tonsillectomies (TE). METHODS: 30 adult patients were treated with oral analgesics (protocol group) and compared to 30 patients treated with a morphine PCIA for the first 3 Postoperative Days (PODs) after TE. Average and maximum pain severities (Numeric Rating Scale - NRS: 0-10) on PODs 1-3, analgesic score, quality of life, patient satisfaction and side effects were defined as outcome measures. RESULTS: Average pain severities of the protocol and the PCIA group were of similar magnitude (NRS) (POD1: 4.48 vs. 4.71 [p = 0.68], POD2: 4.75 vs. 4.22 [p = 0.32] and POD3: 4.44 vs. 4.25 [p = 0.71]). Maximum pain intensities on POD1 (p = 0.92), POD2 (p = 0.51) and POD3 (p = 0.36) were also comparable between both groups. Patients with a PCIA consumed significantly more opioids (p = 0.001) without significant more side-effects. CONCLUSION: The PCIA did not provide a superior pain control compared to oral analgesics. In view of the considerable effort and the high opioid consumption, it cannot be recommended as a standardized application for pain control after TE.

Analgesia after tonsillectomy with controlled intravenous morphine - overdue or exaggerated?

Abstract Objective: To assess the value of a morphine Patient Controlled Intravenous Analgesia (PCIA) after Tonsillectomies (TE). Methods: 30 adult patients were treated with oral analgesics (protocol group) and compared to 30 patients treated with a morphine PCIA for the first 3 Postoperative Days (PODs) after TE. Average and maximum pain severities (Numeric Rating Scale - NRS: 0-10) on PODs 1-3, analgesic score, quality of life, patient satisfaction and side effects were defined as outcome measures. Results: Average pain severities of the protocol and the PCIA group were of similar magnitude (NRS) (POD1: 4.48 vs. 4.71 [p = 0.68], POD2: 4.75 vs. 4.22 [p = 0.32] and POD3: 4.44 vs. 4.25 [p = 0.71]). Maximum pain intensities on POD1 (p = 0.92), POD2 (p = 0.51) and POD3 (p = 0.36) were also comparable between both groups. Patients with a PCIA consumed significantly more opioids (p = 0.001) without significant more side-effects. Conclusion: The PCIA did not provide a superior pain control compared to oral analgesics. In view of the considerable effort and the high opioid consumption, it cannot be recommended as a standardized application for pain control after TE.

Therapeutic Suggestions During General Anesthesia Reduce Postoperative Nausea and Vomiting in High-Risk Patients - A Post hoc Analysis of a Randomized Controlled Trial.

Postoperative nausea and vomiting (PONV) are one of the most adverse events after general anesthesia, a distressing experience, and pose a risk to the patient. Despite advances in drug prophylaxis and PONV treatment, the incidence remains high and additional non-pharmacological treatments are needed. In this post hoc analysis of a recently published double-blind multicenter randomized controlled trial on the efficacy of intraoperative therapeutic suggestions on postoperative opioid dosage, we analyzed the effects of intraoperative therapeutic suggestions on PONV. We focus on patients with a high risk of PONV (Apfel risk score of 3-4) and distinguished early (first two postoperative hours) and delayed PONV (2-24 h). A total of 385 patients with a moderate or high risk for PONV were included. The incidence of early and delayed PONV was reduced (22.7-18.3 and 29.9-24.1%, respectively), without statistical significance, whereas in high-risk patients (n = 180) their incidence was nearly halved, 17.2 vs. 31.2% (p = 0.030) and 20.7 vs. 34.4% (p = 0.040), corresponding to a number needed to treat of 7 to avoid PONV. In addition, there was a significant reduction in PONV severity. In a multivariate logistic regression model, assignment to the control group (OR 2.2; 95% CI: 1.1-4.8) was identified as an independent predictor of the occurrence of early PONV. Our results indicate that intraoperative therapeutic suggestions can significantly reduce the incidence of PONV in high-risk patients. This encourages the expansion of therapeutic suggestions under general anesthesia, which are inexpensive and virtually free of side effects. Clinical Trial Registration: German Clinical Trials Register, https://drks.de, registration number: DRKS00013800.

Model-Based Step Length Estimation Using a Pendant-Integrated Mobility Sensor.

The step length is an important parameter in gait analysis. Long-term monitoring applications for gait analysis are often based on inertial measurement units (IMUs) due to their low-cost and unobtrusive nature. Spatial gait parameters, such as step or stride length, are therefore not directly accessible. In this contribution, we focus on model-based algorithms for step length estimation based on a pendant-integrated IMU during slow walking speeds. We present a model-based approach to estimate the step length, which is divided into two successive steps. As the first part of our approach, we present an algorithm for estimation of the vertical displacement of the center of mass (CoM) during gait. Based on this estimate, we present a novel approach to estimate the step length, which we have deduced from a previously published, simplified gait model. The algorithm is compared to a commonly known approach for accelometry-based step length prediction and validated against reference data obtained from a force plate-integrated treadmill for gait analysis during a clinical study with ten healthy subjects. Due to the applicability to gait stability assessment in elderly or gait impaired patients, we focus on slow walking speeds (1-4 km h-1). The presented algorithms outperform the existing approach and the proposed model calculations provide a more accurate prediction. For the vertical displacement, we achieved a precision of 9.3% (CoV) with an RMSE of 1.5 mm in terms of the trajectory amplitude during normal gait patterns. The step length estimation yields satisfying results with a relative prediction error of lower than 10% for walking speeds of 2-4kmh-1.

Interoceptive Sensibility, Alexithymia, and Emotion Regulation in Individuals Suffering from Fibromyalgia.

INTRODUCTION: People suffering from fibromyalgia syndrome report various difficulties in emotional processing, possibly resulting from changes in bodily perception (interoception). In our study, we investigated the relationships between interoceptive sensibility (IS) and two disease-relevant emotional components (alexithymia and emotion regulation) in fibromyalgia sufferers compared to healthy individuals. METHODS: Fifty-five fibromyalgia sufferers and 55 healthy individuals, matched with regard to age and gender, participated in our cross-sectional study. All participants completed the following self-report measures: the Multidimensional Assessment of Interoceptive Awareness, the Toronto Alexithymia Scale, and the Emotion Regulation Skills Questionnaire. Depression and anxiety scores served as confounding variables. RESULTS: Fibromyalgia sufferers reported a stronger tendency to note as well as to avoid (unpleasant) body sensations. IS and psychopathology each explained about thirty percent of the variance in emotion regulation in fibromyalgia sufferers. Alexithymia was related to IS and emotion regulation in controls but not in fibromyalgia sufferers. CONCLUSION: Disturbances in interoception could be seen as the starting point of emotional difficulties in people with fibromyalgia. Following the fear-avoidance-model, experiential avoidance may restrict patients' ability to adaptively regulate emotional states, possibly initiating a vicious cycle of psychological distress and pain.

Postoperative Pain Treatment With Continuous Local Anesthetic Wound Infusion in Patients With Head and Neck Cancer: A Nonrandomized Clinical Trial.

Importance: Up to 80% of patients with head and neck cancer undergoing ablative surgery and neck dissection develop postoperative pain with detrimental effects on quality of life that also contributes to neuropathic and chronic postoperative pain. Objective: To investigate the association of continuous local anesthetic wound infusion with pain management after head and neck surgery. Design, Setting, and Participants: This prospective, longitudinal, nonrandomized clinical study carried out in a single tertiary referral center (December 1, 2015, to July 1, 2017) included 2 groups of 30 patients. Patients were consecutively enrolled and presented for ablative head and neck surgery including selective neck dissection and studied from the preoperative through the fourth postoperative day. Interventions: The control group was treated according to a standardized escalating oral treatment protocol (ibuprofen, metamizole, opioids). The intervention group was treated with an intraoperatively applied pain catheter (InfiltraLong plus FuserPump, Pajunk, ropivacaine, 0.2%, 3 mL/h) that was removed 72 hours after operating. Main Outcomes and Measures: Average and maximum pain intensities on a numeric rating scale; quality of life using the acute version of the validated 36-Item Short Form Survey; and neuropathic pain using the validated 12-Item painDETECT questionnaire. Consumption of opioid and nonopioid analgesics and evaluation of catheter-associated complications. Results: During postoperative days 1 through 4, patients of the intervention group (mean [SD] age, 63.2 [13.3 years; 9 [30%] women) experienced lower mean (SD) (1.6 [1.4] vs 2.7 [1.8]; η2p = 0.09 [0.01-0.21]) and maximum (2.4 [2.2] vs 4.2 [2.0]; η2p = 0.11 [0.01-0.24]) pain intensities compared with the control group (mean [SD] age, 62.5 [13.6] years; 5 [17%] women). The intervention group also reported less neuropathic pain (mean [SD], 5.4 [3.4] vs 7.6 [5.1]; η2p = 0.09 [0.004 - 0.22]) and higher quality of life regarding vitality (56.2 [21.5] vs 43.8 [20.9], r = 0.29; 95% CI, 0.01-0.52) and pain (66.8 [27.3] vs 49.5 [27.7], r = 0.31; 95% CI, 0.04-0.54). Patients from the intervention group requested nonopioid analgesics considerably less often (n = 17 [57% ]vs n = 29 [97%]; ϕ = 0.47; 95% CI, 0.30-0.67) associated with a noticeably lower need to escalate pain treatment (n = 3 [10%] vs n = 9 [30%]; mean [SD] ibuprofen dose: 500 [173] mg vs 1133 [650] mg; r = 0.64; 95% CI, 0.02-0.91). No catheter-associated complications were observed. Conclusions and Relevance: Continuous anesthetic wound infusion is associated with reduced postoperative pain and decreased demand for analgesics. It therefore expands the treatment options for postoperative pain in head and neck cancer. Trial Registration: German Clinical Trials Register: DRKS00009378.

Verbal Motivation vs. Digital Real-Time Feedback during Cardiopulmonary Resuscitation: Comparing Bystander CPR Quality in a Randomized and Controlled Manikin Study of Simulated Cardiac Arrest.

OBJECTIVE: The use of smartphone applications increases bystander CPR quality as well as the use of telephone CPR protocols. The present prospective, randomized, controlled manikin trial analyses the effects of a smartphone application (PocketCPR©) on CPR quality in a bystander CPR scenario compared to a dispatcher-assisted telephone CPR with the additional use of a metronome and verbal motivation. Methods: 150 laypersons were included to perform 8-minute CPR on a manikin. Volunteers were randomly assigned to one of three groups: (1) dispatcher-assisted telephone CPR (telephone-group), (2) dispatcher-assisted telephone CPR combined with the smartphone-application (telephone + app-group) and (3) dispatcher-assisted telephone CPR with additional verbal motivation ("push harder, release completely," every 20 seconds, starting after 60 seconds) and a metronome with 100 min-1 (telephone + motivation-group). Results: Median compression depth did not differ significantly between the study groups (p = 0.051). However, in the post hoc analysis median compression depth in the telephone + motivation-group was significantly elevated compared to the telephone + app-group (59 mm [IQR 47-67 mm] vs. 51 mm [IQR 46-57 mm]; p = 0.025). The median number of superficial compressions was significantly reduced in the telephone + motivation-group compared to the telephone + app-group (70 [IQR 3-362] vs. 349 [IQR 88-538]; p = 0.004), but not compared to the telephone-group (91 [IQR 4-449]; p = 0.707). In contrast to the other study groups, median compression depth of the telephone + motivation-group increased over time. Chest compressions with correct depth were found significantly more often in the telephone + app-group compared to the other study groups (p = 0.011). Median compression rate in the telephone + app-group was significantly elevated (108 min-1 [IQR 96-119 min-1]) compared to the telephone-group (78 min-1 [IQR 56-106 min-1]; p < 0.001) and the telephone + motivation-group (99 min-1 [IQR 91-101 min-1]; p < 0.001). Conclusions: The use of a smartphone application as well as verbal motivation by a dispatcher during telephone CPR leads to higher CPR quality levels compared to standard telephone CPR. Thereby, the use of the smartphone application mainly shows an increase in compression rate, while increased compression rate with simultaneously increased compression depth was only apparent in the telephone + motivation-group.

Effect of therapeutic suggestions during general anaesthesia on postoperative pain and opioid use: multicentre randomised controlled trial.

OBJECTIVE: To investigate the effect of therapeutic suggestions played to patients through earphones during surgery on postoperative pain and opioid use. DESIGN: Blinded randomised controlled study. SETTING: Five tertiary care hospitals in Germany. PARTICIPANTS: 385 of 400 patients consecutively recruited from January to December 2018 who were to undergo surgery for 1-3 hours under general anaesthesia. In the per protocol analysis 191 patients were included in the intervention group and 194 patients in the control group. INTERVENTION: The intervention comprised an audiotape of background music and positive suggestions based on hypnotherapeutic principles, which was played repeatedly for 20 minutes followed by 10 minutes of silence to patients through earphones during general anaesthesia. Patients in the control group were assigned to a blank tape. MAIN OUTCOME MEASURES: The main outcome was dose of opioid administered by patient controlled analgesia or nurse controlled analgesia within the first postoperative 24 hours, based on regular evaluation of pain intensity on a numerical rating scale (range 0-10, with higher scores representing more severe pain). RESULTS: Compared with the control group, the intervention group required a significantly (P=0.002) lower opioid dose within 24 hours after surgery, with a median of 4.0 mg (interquartile range 0-8) morphine equivalents versus 5.3 (2-12), and an effect size (Cohen's d) of 0.36 (95% confidence interval 0.16 to 0.56). The number of patients who needed opioids postoperatively was significantly (P=0.001) reduced in the intervention group: 121 of 191 (63%, 95% confidence interval 45% to 70%) patients in the intervention group versus 155 of 194 (80%, 74% to 85%) in the control group. The number needed to treat to avoid postoperative opioids was 6. Pain scores were consistently and significantly lower in the intervention group within 24 hours after surgery, with an average reduction of 25%. No adverse events were reported. CONCLUSIONS: Therapeutic suggestions played through earphones during general anaesthesia could provide a safe, feasible, inexpensive, and non-drug technique to reduce postoperative pain and opioid use, with the potential for more general use. Based on the finding of intraoperative perception by a considerable number of patients, surgeons and anaesthetists should be careful about background noise and conversations during surgery. TRIAL REGISTRATION: German Clinical Trial Register DRKS00013800.

Hirudotherapy attenuates arthritic pain in patients with various chronic pain syndromes: A retrospective analysis.

OBJECTIVE: Osteoarthritis is a degenerative disease that affects synovial joints. Micro-injuries of articular structures initiate inflammatory processes, leading to persistent pain. Due to various risk factors, osteoarthritis is often diagnosed in multimorbid patients. This makes pain management one of the key challenges, with a consistent need for new therapeutic strategies. Hence, complementary and integrative methods such as hirudotherapy have become increasingly important, even though their mechanisms of action are not entirely understood. METHODS: We retrospectively analyzed the longitudinal effect of a single leech application on osteoarthritic joints in a heterogenic cohort of 24 cases with various chronic pain syndromes. We assessed articular pain intensity ratings and movability of the treated joint after one-time leeching for up to 12 months. We further investigated the effect of hirudotherapy on the systemic pain status and multimodal treatment strategies of the patients. RESULTS: There was a significant reduction in pain intensity ratings at the joint of leech application for up to 12 months after treatment. The improvements in pain intensities were independent of the form of osteoarthritis treated. In addition, we saw a considerable enhancement in local movability of the treated joint. Hirudotherapy did not seem to influence the systemic pain status as well as the previously established individualized multimodal treatment model of the patients. CONCLUSION: Leeching as an adjuvant therapy has a great potential especially in terms of safety and long-term outcome.

Pain after External and Endonasal Septorhinoplasty-A Propensity Score Matching Analysis.

Guidelines for pain management following septorhinoplasty are lacking, leading to a wide range of therapy regimes even including opioid medication. Thus, the presented study strived to investigate and compare postoperative pain intensities after external and endonasal septorhinoplasty and evaluate whether pain perception is potentially related to patient satisfaction with the aesthetic result. In addition, the effectiveness of an escalating pain treatment protocol was evaluated sparing the necessity of opioid medication. This retrospective study performed at a tertiary referral medical center includes two well-balanced groups of 54 patients each created by propensity score matching out of a total of 161 patients following external or endonasal functional septorhinoplasty performed by a single surgeon between October 1, 2011 and March 31, 2017. Pain intensity was assessed using the visual analogue scale (0-10) on the first three postoperative days (PODs) alongside with the evaluation of the analgesic score. Patients' self-reported outcome was measured with the Utrecht questionnaire, preoperatively, and 3 and 12 months, postoperatively. Postoperative mean pain sensations were similarly high following the external and endonasal approach (F (2;190) = 2.166, p = 0.118) followed by a linear decrease over the first three PODs (F (2;190) = 16.84, p < 0.001). Pain sensations were not related to the duration of surgery, gender, patients' age, revision surgery, and the preoperative and postoperative assessment of the nasal appearance. The consumption of metamizole (F (1,76;172,15) = 2.83, p = 0.065) and ibuprofen (F (2;196) = 1.037, p = 0.356) were similarly high regardless of the surgical approach. Accordingly, both the endonasal and the external approaches led to comparable postoperative pain intensities and analgesic scores. Pain was treated effectively using a standardized escalating pain treatment protocol sparing the administration of opioids. Pain was not related to patient satisfaction with the nasal appearance pre- and postsurgery.

Postoperative pain after tonsillectomy - the value of standardized analgesic treatment protocols.

OBJECTIVE: To alleviate pain after tonsillectomy (TE) with escalating gradual treatment protocols in a prospective trial. MATERIALS & METHODS: Following TE, 83 consecutive adult patients were treated with two different four-staged escalating analgesic protocols. Metamizole served as basic medication in protocol 1 (PT1; n = 44), whereas with protocol 2 (PT2; n = 39) ibuprofen was applied as baseline analgesic. Both protocols were escalated according to the patient´s needs to metamizole and ibuprofen vice versa and additional weak to strong opioids. The primary efficacy endpoint was defined as the minimum and maximum pain as well as pain on ambulation (NRS, 0-10). Secondary endpoints comprised analgesic score, patient satisfaction and treatment-related side-effects. RESULTS: Both patient groups exhibited similar demographic characteristics (PT1: Ø 28.8 years; 64% ♀ and PT2: Ø 26.6 years; 56% ♀). Maximum pain (6.7 ±â€¯1.9 vs. 7.6 ±â€¯1.6, t(81) = -2.254, p = 0.027) and pain on ambulation (5.0 ±â€¯1.8 vs. 5.8 ±â€¯1.8, t(81) = -2.114, p = 0.038) were significantly higher with PT2. 68.2% of patients with PT1 needed an escalation of analgesic treatment compared to 100% with PT2 (p < 0.001). The opioid consumption was also significantly higher with PT2 (43.2% vs. 71.8%, p < 0.001). There were no significant differences regarding functional impairments, side-effects and patient satisfaction (7.0 ±â€¯2.0 vs. 7.4 ±â€¯2.4, t(79) = -0.897, p = 0.373). CONCLUSION: Both treatment protocols yielded in a high degree of patient satisfaction but dissatisfactory pain relief following TE. Metamizole can be recommended as a basic medication allowing for improved pain relief. Reported pain intensities were independent of the amount of opioid intake. Further research is mandatory to standardize and improve analgesic treatment after TE.

Postoperative pain following Descemet membrane endothelial keratoplasty (DMEK): a prospective study.

PURPOSE: To evaluate postoperative pain following Descemet membrane endothelial keratoplasty (DMEK). METHODS: Seventy-one patients completed perioperatively (day before surgery, day of surgery, 1st, 2nd, and 3rd day after surgery) four different questionnaires (a hospital internal protocol, QUIPS, PainDETECT®, and SF36) regarding their pain and other clinical parameters such as constipation, tiredness, vertigo, sleep disorders, concentration disorders, nausea, and emesis. All standardised questionnaires were evaluated to quantify average pain intensity as well as maximum pain intensity (NRS, 0 [no pain] to 10 [maximal pain], respectively). Analgesic treatment and intraocular pressure (IOP) during the perioperative stay were documented. RESULTS: Mean average pain intensity was 0.70 ± 1.64 before surgery, 1.97 ± 2.05 on the day of surgery, 1.39 ± 1.68 on day 1, 0.87 ± 1.36 on day 2, and 0.81 ± 1.24 on day 3 after surgery. Maximum pain intensity was 0.65 ± 1.81 before surgery, 3.35 ± 2.98 on the day of surgery, 2.68 ± 2.99 on day 1, 1.49 ± 2.15 on day 2, and 1.26 ± 2.02 on day 3 after surgery. During the first three postoperative days, over 90% of the patients stated no or well tolerable pain. Eighty-three percent had postoperatively no need for analgesics at all. On the first two postoperative days, maximum IOP correlated significantly with reported increased maximum pain intensity (p = 0.043 and p = 0.029, respectively). All patients had very little problems with constipation, tiredness, vertigo, sleep disorder, concentration disorders, nausea, and emesis. CONCLUSIONS: DMEK is associated with low postoperative pain intensity. Strong pain increase may indicate IOP elevation and should be further investigated and treated. CLINICAL TRIAL REGISTRATION: German Clinical Trial Register (DRKS00013995).

Beneficial effects of hirudotherapy in a chronic case of complex regional pain syndrome.

We report about hirudotherapy in a patient with chronic complex regional pain syndrome (CRPS) in the right hand. CRPS is a multifactorial disease associated with disabling pain as well as sensory and motor deficits. The optimal therapeutic management is based on personalized multimodal treatment approaches; however, hirudotherapy has not been described in the available literature. To date, we have completed five medicinal leech treatments. Altogether, hirudotherapy led to rapid and substantial relief of symptoms, especially with respect to pain intensity ratings and skin temperature asymmetries. In addition, the patient's active and passive agility of the affected limb improved obviously.