Surveillance of high-risk early postsurgical patients for real-time detection of complications using wireless monitoring (SHEPHERD study): results of a randomized multicenter stepped wedge cluster trial

Background

Vital signs measurements on the ward are performed intermittently. This could lead to failure to rapidly detect patients with deteriorating vital signs and worsens long-term outcome. The aim of this study was to test the hypothesis that continuous wireless monitoring of vital signs on the postsurgical ward improves patient outcome.

Methods

In this prospective, multicenter, stepped-wedge cluster randomized study, patients in the control group received standard monitoring. The intervention group received continuous wireless monitoring of heart rate, respiratory rate and temperature on top of standard care. Automated alerts indicating vital signs deviation from baseline were sent to ward nurses, triggering the calculation of a full early warning score followed. The primary outcome was the occurrence of new disability three months after surgery.

Results

The study was terminated early (at 57% inclusion) due to COVID-19 restrictions. Therefore, only descriptive statistics are presented. A total of 747 patients were enrolled in this study and eligible for statistical analyses, 517 patients in the control group and 230 patients in the intervention group, the latter only from one hospital. New disability at three months after surgery occurred in 43.7% in the control group and in 39.1% in the intervention group (absolute difference 4.6%).

Conclusion

This is the largest randomized controlled trial investigating continuous wireless monitoring in postoperative patients. While patients in the intervention group seemed to experience less (new) disability than patients in the control group, results remain inconclusive with regard to postoperative patient outcome due to premature study termination.

Clinical trial registration

ClinicalTrials.gov, ID: NCT02957825.

The demographics of persistent opioid consumption following limb amputation

BACKGROUND

Patients who have limb amputation are at risk of chronic pain, including phantom limb pain that can be challenging to treat. The aim of this study was to describe the incidence of pre-operative opioid usage and the incidence and risk factors for new persistent post-operative opioid usage in opioid-naïve patients after limb amputation.

METHODS

A retrospective study of all patients 18 years and older underwent upper or lower extremity amputations in Landspitali University Hospital between 2005 and 2015. Patients were considered to use opioids pre-operatively if they filled an opioid prescription 1-6 months prior to amputation and were considered to have persistent opioid use if opioid prescriptions were filled between post-operative months four to twenty-four. In addition to incidence estimate, uni- and multivariate analysis was performed to identify risk factors for persistent post-operative opioid usage.

RESULTS

Of 328 total patients, 216 (66%) were opioid naïve and 112 (34%) were chronic opioid users. Of the opioid-naïve patients surviving more than 3 months 40 (20%) developed persistent post-operative opioid usage. In multivariate analysis, factors independently associated with persistent post-operative opioid usage were younger age, male gender, pre-operative use of neuropathic medications or benzodiazepines and lower (opposed to upper) extremity amputation.

CONCLUSION

Opioid naïve patients undergoing major amputation had a 20% chance of having a persistent opioid requirement following surgery. This could represent new-onset phantom limb pain or other chronic pain. Our findings should encourage perioperative multimodal efforts to reduce the burden of chronic pain after limb amputations.

Ultrasound guided supra-inguinal Fascia Iliaca Compartment Blocks in hip fracture patients: An alternative technique

INTRODUCTION

In the Emergency Department, regional anesthesia is increasingly used in elderly patients with hip fractures. An example is a Fascia Iliaca Compartment Block (FICB). Traditionally, this block is administered below the inguinal ligament. There is no Emergency Department data regarding effectivity of an alternative, more cranial approach above the inguinal ligament. The objective was to determine analgesic effects of an ultrasound-guided supra-inguinal FICB in hip fracture patients in the Emergency Department.

METHODS

This case series included all Emergency Department hip fracture patients who were treated with a supra-inguinal FICB during a period of 10 months. All data were recorded prospectively. Primary study outcome was decrease in Numerical Rating Scale (NRS) pain scores 60 min after the FICB. Secondary outcomes included the proportion of patients achieving 1.5 NRS points decrease at 60 min; NRS differences at 30 and 120 min compared to baseline; need for additional analgesia and occurrence of adverse events.

RESULTS

A total of 22 patients were included in the study. At 60 min median NRS pain scores decreased from 6.0 to 3.0 (p < 0.001). Of all patients, a total of 59% achieved a decrease in 1.5 NRS points after 60 min. Median pain scores at 30 and 120 min were 4.0 (Interquartile Range (IQR) 2.0-5.0) and 2.5 (IQR 0.8-3.0). Seven patients (31.8%) required additional opioid analgesia after the FICB. No adverse events were recorded.

CONCLUSION

An ultrasound-guided supra-inguinal FICB decreases NRS pain scores in hip fracture patients both clinically relevant and statistically significantly after 60 min.

CLINICAL TRIAL REGISTRATION

The study was registered in the ISRCTN database (ISRCTN74920258).

Perioperative Anesthesia Care and Tumor Progression

This narrative review discusses the most recent up-to-date findings focused on the currently available "best clinical practice" regarding perioperative anesthesia care bundle factors and their effect on tumor progression. The main objective is to critically appraise the current literature on local anesthetics, regional outcome studies, opioids, and nonsteroidal anti-inflammatory drugs (NSAIDs) and their ability to decrease recurrence in patients undergoing cancer surgery. A brief discussion of additional topical perioperative factors relevant to the anesthesiologist including volatile and intravenous anesthetics, perioperative stress and anxiety, nutrition, and immune stimulation is included. The results of several recently published systematic reviews looking at the association between cancer recurrences and regional anesthesia have yielded inconclusive data and provide insufficient evidence regarding a definitive benefit of regional anesthesia. Basic science data suggests an anti tumor effect induced by local anesthetics. New refined animal models show that opioids can safely be used for perioperative pain management. Preliminary evidence suggests that NSAIDs should be an essential part of multimodal analgesia. Volatile anesthetics have been shown to increase tumor formation, whereas preclinical and emerging clinical data from propofol indicate tumor protective qualities. The perioperative period in the cancer patient represents a unique environment where surgically mediated stress response leads to immune suppression. Regional anesthesia techniques when indicated in combination with multimodal analgesia that include NSAIDs, opioids, and local anesthetics to prevent the pathophysiologic effects of pain and neuroendocrine stress response should be viewed as an essential part of balanced anesthesia.

NMDA Receptor Antagonist Ketamine Distorts Object Recognition by Reducing Feedback to Early Visual Cortex

It is a well-established fact that top-down processes influence neural representations in lower-level visual areas. Electrophysiological recordings in monkeys as well as theoretical models suggest that these top-down processes depend on NMDA receptor functioning. However, this underlying neural mechanism has not been tested in humans. We used fMRI multivoxel pattern analysis to compare the neural representations of ambiguous Mooney images before and after they were recognized with their unambiguous grayscale version. Additionally, we administered ketamine, an NMDA receptor antagonist, to interfere with this process. Our results demonstrate that after recognition, the pattern of brain activation elicited by a Mooney image is more similar to that of its easily recognizable grayscale version than to the pattern evoked by the identical Mooney image before recognition. Moreover, recognition of Mooney images decreased mean response; however, neural representations of separate images became more dissimilar. So from the neural perspective, unrecognizable Mooney images all "look the same", whereas recognized Mooneys look different. We observed these effects in posterior fusiform part of lateral occipital cortex and in early visual cortex. Ketamine distorted these effects of recognition, but in early visual cortex only. This suggests that top-down processes from higher- to lower-level visual areas might operate via an NMDA pathway.

NMDA receptor antagonist ketamine impairs feature integration in visual perception

Recurrent interactions between neurons in the visual cortex are crucial for the integration of image elements into coherent objects, such as in figure-ground segregation of textured images. Blocking N-methyl-D-aspartate (NMDA) receptors in monkeys can abolish neural signals related to figure-ground segregation and feature integration. However, it is unknown whether this also affects perceptual integration itself. Therefore, we tested whether ketamine, a non-competitive NMDA receptor antagonist, reduces feature integration in humans. We administered a subanesthetic dose of ketamine to healthy subjects who performed a texture discrimination task in a placebo-controlled double blind within-subject design. We found that ketamine significantly impaired performance on the texture discrimination task compared to the placebo condition, while performance on a control fixation task was much less impaired. This effect is not merely due to task difficulty or a difference in sedation levels. We are the first to show a behavioral effect on feature integration by manipulating the NMDA receptor in humans.