Argipressin for prevention of blood loss during liver resection: a study protocol for a randomised, placebo-controlled, double-blinded trial (ARG-01)

INTRODUCTION

Liver resection carries a high risk for extensive bleeding and need for blood transfusions, which is associated with significant negative impact on outcome. In malignant disease, the most common indication for surgery, it also includes increased risk for recurrence of cancer. Argipressin decreases liver and portal blood flow and may have the potential to reduce bleeding during liver surgery, although this has not been explored.

METHOD AND ANALYSIS

ARG-01 is a prospective, randomised, placebo-controlled, double-blinded study on 248 patients undergoing liver resection at Sahlgrenska University Hospital, Sweden. Patients will be randomised to one of two parallel groups, infusion of argipressin or normal saline administered peroperatively. The primary endpoint is peroperative blood loss. Secondary outcomes include need for blood transfusion, perioperative variables, length of hospital stay, the inflammatory response, organ damage markers and complications at 30 days.

ETHICS AND DISSEMINATION

The study is enrolling patients since March 2022. The trial is approved by the Swedish Ethical Review Authority (Dnr 2021-03557) and the Swedish Medical Product Agency (Dnr 5.1-2021-90115). Results will be announced at scientific meetings and in international peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov, NCT05293041 and EudraCT, 2021-001806-32.

Protein tau concentration in blood increases after SCUBA diving: an observational study

Purpose

It is speculated that diving might be harmful to the nervous system. The aim of this study was to determine if established markers of neuronal injury were increased in the blood after diving.

Methods

Thirty-two divers performed two identical dives, 48 h apart, in a water-filled hyperbaric chamber pressurized to an equivalent of 42 m of sea water for 10 min. After one of the two dives, normobaric oxygen was breathed for 30 min, with air breathed after the other. Blood samples were obtained before and at 30–45 and 120 min after diving. Concentrations of glial fibrillary acidic, neurofilament light, and tau proteins were measured using single molecule array technology. Doppler ultrasound was used to detect venous gas emboli.

Results

Tau was significantly increased at 30–45 min after the second dive (p < 0.0098) and at 120 min after both dives (p < 0.0008/p < 0.0041). Comparison of matching samples showed that oxygen breathing after diving did not influence tau results. There was no correlation between tau concentrations and the presence of venous gas emboli. Glial fibrillary acidic protein was decreased 30–45 min after the first dive but at no other point. Neurofilament light concentrations did not change.

Conclusions

Tau seems to be a promising marker of dive-related neuronal stress, which is independent of the presence of venous gas emboli. Future studies could validate these results and determine if there is a quantitative relationship between dive exposure and change in tau blood concentration.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00421-022-04892-9.

Myocardial, renal and intestinal injury in liver resection surgery-A prospective observational pilot study

BACKGROUND

Post-operative organ complications in liver resection surgery are not uncommon. This prospective observational pilot study was performed to evaluate the incidence, degree and timing of myocardial, renal and intestinal injury in patients undergoing liver resection surgery using the low central venous pressure (LCVP) technique and the Pringle manoeuvre.

METHODS

Blood samples were obtained before, during and after elective liver resection until post-operative day (POD) 5. High-sensitive troponin T (hs-TnT), serum creatinine, urea, intestinal fatty acid binding protein (I-FABP), D-lactate, arterial lactate, portal lactate, amylase, as well as urine N-acetyl-ß-D-glucosaminidase (NAG) were analysed. Systemic haemodynamics were measured intraoperatively.

RESULTS

Eighteen patients fulfilled the protocol. The Pringle manoeuvre was used in all but 1 patient. hs-TnT increased significantly over time (P < .001) and 5 patients (28%) developed myocardial injury. Five patients had a pre-operative elevation of hs-TnT, four of those developed myocardial injury. Serum creatinine increased significantly over time (P = .015). Acute kidney injury (AKI) occurred in 5 patients (28%), while NAG, as a marker of tubular injury, was not affected. I-FABP increased over time (P < .001) with a maximal 75% increase at 3 hours after resection. D-lactate was below detection level at all measuring points.

CONCLUSIONS

In patients undergoing liver resection surgery, using LCVP technique and Pringle manoeuvre, myocardial injury was seen in approximately 30% of the patients post-operatively and almost 30% developed transient AKI in the early post-operative period with no tubular injury. Furthermore, a transient increase of the enterocyte damage marker I-FABP was demonstrated with no signs of gut barrier dysfunction.

Serum tau concentration after diving - an observational pilot study

INTRODUCTION

Increased concentrations of tau protein are associated with medical conditions involving the central nervous system, such as Alzheimer's disease, traumatic brain injury and hypoxia. Diving, by way of an elevated ambient pressure, can affect the nervous system, however it is not known whether it causes a rise in tau protein levels in serum. A prospective observational pilot study was performed to investigate changes in tau protein concentrations in serum after diving and also determine their relationship, if any, to the amount of inert gas bubbling in the venous blood.

METHODS

Subjects were 10 navy divers performing one or two dives per day, increasing in depth, over four days. Maximum dive depths ranged from 52-90 metres' sea water (msw). Air or trimix (nitrogen/oxygen/helium) was used as the breathing gas and the oxygen partial pressure did not exceed 160 kPa. Blood samples taken before the first and after the last dives were analyzed. Divers were monitored for the presence of venous gas emboli (VGE) at 10 to15 minute intervals for up to 120 minutes using precordial Doppler ultrasound.

RESULTS

Median tau protein before diving was 0.200 pg·mL⁻¹ (range 0.100 to 1.10 pg·mL⁻¹) and after diving was 0.450 pg·mL⁻¹ (range 0.100 to 1.20 pg·mL⁻¹; P = 0.016). Glial fibrillary acidic protein and neurofilament light protein concentrations analyzed in the same assay did not change after diving. No correlation was found between serum tau protein concentration and the amount of VGE.

CONCLUSION

Repeated diving to between 52-90 msw is associated with a statistically significant increase in serum tau protein concentration, which could indicate neuronal stress.

Cerebrospinal fluid markers of central nervous system injury in decompression illness - a case-controlled pilot study

INTRODUCTION

Decompression sickness (DCS) may cause a wide variety of symptoms, including central nervous system (CNS) manifestations. The main objective of this study was to examine whether DCS is associated with neuronal injury, and whether DCS could result in altered amyloid metabolism.

METHODS

Seven, male divers with DCS and seven age-matched controls were included in the study. All the divers were treated by recompression but the controls did not receive hyperbaric oxygen. Cerebrospinal fluid (CSF) samples were collected 7-10 days after the diving injury and at three months follow-up. CSF biomarkers of neuronal injury, astroglial Injury/activation, and a range of markers of amyloid β (Aβ) metabolism, as well as two proinflammatory interleukins, were analysed using immunochemical methods.

RESULTS

There were no significant differences in the best-established CSF markers of neuronal injury, total tau (T-tau) and neurofilament light, between DCS patients and controls or between the two sampling time points. Also, there were no significant changes in the astroglial or amyloid (Aβ)-related markers between DCS patients and controls. However, the only diver with CNS symptoms had the highest levels of CSF T-tau, Aβ38, Aβ40 and Aβ42.

CONCLUSION

The results of our study speak against subclinical CNS injury or induction of inflammation or amyloid build-up in the brain among the six DCS patients without neurological symptoms. Further research, including on divers with CNS DCS, is justified.

Alternative pathway activation of complement in laparoscopic and open rectal surgery

The study was designed to investigate whether complement is activated in patients subject to rectal surgery and whether the choice of surgical technique (open or laparoscopic) has any impact on the activation of complement. Our hypothesis is that laparoscopic surgery leads to a lower-level activation of complement than open surgery. Patients (n = 24) subject to rectal surgery owing to rectal cancer were included. The study was prospective and randomized. The patients were randomized to either laparoscopic surgery (n = 12) or open surgery (n = 12). Blood samples for determination of complement activation (C4d, Bb, C3bc and the terminal C5b-9 complex TCC) were drawn before start of surgery (T0) and at the following time-points after start of surgery: 180 min (T1), 360 min (T2), 24 h (T3) and 3-5 days (T4). A significant increase in the alternative pathway activation product Bb and in the terminal pathway activation product TCC was seen over time in both groups (P < 0.001). Bb peaked early (T1) and returned to baseline levels post-operatively, whereas TCC increased steadily with maximum values in the late post-operative period. The plasma concentrations of C4d and C3bc decreased significantly in both groups at T1 and T2 and returned to baseline levels at T4. There was no significant difference between the groups. Rectal surgery causes activation of the complement system. Complement is activated through the alternative pathway. Results mostly showed no significant differences between laparoscopic and open rectal surgery apart from lower levels of factor Bb in the former group in the perioperative period.

Inflammatory response in patients undergoing colorectal cancer surgery: the effect of two different anesthetic techniques

BACKGROUND

Anesthesia during surgery often induces an inflammatory response. The aim of this study was to establish and compare differences in inflammatory response among colorectal cancer surgery patients receiving either total intravenous anesthesia (TIVA) with propofol and remifentanil or inhalational anesthesia (INHAL) with sevoflurane and fentanyl.

METHODS

After randomization, we included fifty consecutive patients undergoing colorectal cancer surgery in our study. TIVA patients received total intravenous anesthesia with propofol and remifentanil, while INHAL patients received inhalation anesthesia with sevoflurane in O2/air and fentanyl. Plasma concentrations of IL-8, IL-17, MPO, ICAM-1, V-CAM and L-selectin were quantified. Blood loss, body temperature and blood glucose levels were measured in patients both before and after surgery.

RESULTS

In both groups, levels of IL-8, MPO, ICAM-1 and L-selectin decreased 60 min after the start of surgery (P<0.05, P<0.01, respectively) and 30 min post-surgery (P<0.05 for both groups). In the INHAL group, V-CAM levels were significantly lower 60 min after the start of surgery (P<0.01) and 30 min post-surgery (P<0.05). At 24 h post-surgery, V-CAM levels were significantly higher in both groups (P<0.01), while IL-17 levels significantly increased only in the INHAL group (P<0.05). Higher blood glucose levels were also observed in the INHAL group compared to that in the TIVA group (P<0.01).

CONCLUSION

TIVA with propofol and remifentanil and INHAL with sevoflurane and fentanyl induced similar inflammatory responses during colorectal cancer surgery. We found that IL-17 cytokine levels were higher in patients anesthetized with sevoflurane and fentanyl.

Complement split products and proinflammatory cytokines in intraoperatively salvaged unwashed blood during hip replacement: comparison between heparin-coated and non-heparin-coated autotransfusion systems

BACKGROUND AND OBJECTIVES

The aim of the present study was to investigate the quality of shed blood collected in a new intraoperative autotransfusion system (Sangvia, AstraTech, Sweden) and to study whether heparin-coated surfaces in the device reduce the production of inflammatory mediators.

MATERIAL AND METHODS

The study was randomized and prospective. Twelve total hip arthroplasty patients whose blood was collected with a device having a heparin-coated surface and 12 patients whose blood was collected with a device having a non-heparin-coated surface were included. Venous blood was drawn from the patients preoperatively. Intraoperatively 200 ml salvaged blood was collected and samples were also withdrawn; samples were obtained from the blood bag.

RESULTS

Compared to venous blood, elevated concentrations of interleukin 6 (IL-6), IL-8, C3a and polymorphonuclear elastase were found in collected blood. No significant differences in inflammatory mediators were found between the heparin-coated and the non-heparin-coated groups. The median haemoglobin concentration in the salvaged blood was 74 g/l in both groups. Plasma haemoglobin and potassium concentrations were also elevated. There were no significant differences between the groups.

CONCLUSION

The present study indicates that the blood salvaged intraoperatively contains elevated levels of complement split product and proinflammatory cytokines and that heparin-coated surfaces of the salvage device do not significantly influence the formation of inflammatory mediators.

The analgesic effect of intravenous ketamine and lidocaine on pain after spinal cord injury

BACKGROUND

Pain following spinal cord injury (SCI) is a therapeutic challenge. Only a few treatments have been assessed in randomized, controlled trials. The primary objective of the present study was to examine the analgesic effect of ketamine and lidocaine in a group of patients with neuropathic pain below the level of spinal cord injury. We also wanted to assess sensory abnormalities to see if this could help us to identify responders and if treatments resulted in changes of sensibility.

METHODS

Ten patients with spinal cord injury and neuropathic pain below the level of injury were included. The analgesic effect of ketamine 0.4 mg kg(-1) and lidocaine 2.5 mg kg(-1) was investigated. Saline was used as placebo. The drugs were infused over 40 min. A randomized, double-blind, three-period, three-treatment, cross-over design was used. Systemic plasma concentrations of ketamine and lidocaine were assessed. Pain rating was performed using a visual analogue scale (VAS). Sensory function was assessed with a combination of traditional sensory tests and quantitative measurement of temperature thresholds.

RESULTS

Response to treatment, defined as 50% reduction in VAS-score during infusion, was recorded in 5/10 in the ketamine, 1/10 in the lidocaine and 0/10 in the placebo groups. Neither ketamine nor lidocaine changed temperature thresholds or assessments of mechanical; dynamic and static sensibility. Nor could these sensory assessments predict response to treatment in this setting. Lidocaine and particularly ketamine were associated with frequent side-effects.

CONCLUSION

Ketamine but not lidocaine showed a significant analgesic effect in patients with neuropathic pain after spinal cord injury. The pain relief was not associated with altered temperature thresholds or other changes of sensory function.

The effectiveness of intravenous ketamine and lidocaine on peripheral neuropathic pain

BACKGROUND

Neuropathic pain is often severe and resistant to pharmacological treatment. The aims of the present study were to assess the analgesic effect of ketamine and lidocaine and to investigate if measurement of different variables of sensibility could be used to identify responders. We also wanted to study if treatment resulted in changes of sensibility.

METHODS

Twelve patients with long-lasting peripheral neuropathic pain of traumatic origin were included. The effects of ketamine hydrochloride (Ketalar, Parke Davis) 0.4 mg/kg and lidocaine hydrochloride (Xylocain, Astra) 2.5 mg/kg were investigated. Saline was used as placebo. The intensity of continuous pain was measured by a visual analogue scale (VAS). Warm and cold perception as well as heat and cold pain thresholds were assessed. Sensibility to touch was also tested. Systemic plasma concentrations of lidocaine and ketamine were assessed.

RESULTS

The mean reduction in VAS-scores was 55%, 34% and 22% for ketamine, lidocaine and placebo, respectively. A significant difference was registered between ketamine and placebo (P = 0.009). Response to treatment (50% reduction in VAS-score during infusion) was recorded in 7/12 in the ketamine, 4/12 in the lidocaine and 2/12 in the placebo group. Quantitative sensory testing (QST) of thermal sensitivity and sensory tests for mechanical stimuli could not separate responders from non-responders and neither were the results from these assessments changed by the infusion of the drugs. Lidocaine and particularly ketamine were associated with frequent side-effects, the most common being somnolence and dizziness.

CONCLUSION

Ketamine showed a significant analgesic effect. The clinical usefulness is, however, limited by disturbing side-effects.

Peripheral neuropathic pain--a multidimensional burden for patients

The present study was undertaken to assess the health-related quality of life (HRQoL) and burden of illness due to pain and its treatment for patients with peripheral neuropathic pain (PNP). It is the first step in finding reliable instruments/targets to evaluate treatment outcome in this patient population. Study population consisted of 126 patients suffering from neuropathic pain due to a peripheral nerve or root lesion, recruited from two multidisciplinary pain clinics. HRQoL was examined using Short Form 36 (SF-36) Health Survey and Nottingham Health Profile (NHP). Pain intensity in four categories (at rest and evoked by movement, touch and cold) was rated on a visual analogue scale (VAS). Degree of discomfort from pain and 25 symptoms related to pain and side-effects was also assessed. Reduction in workload due to pain was recorded, as was the pain relief from previous and current treatments and the reasons for discontinuing previous treatments. All dimensions in SF-36 and NHP were significantly impaired. SF-36 was a valid instrument for describing the impact of pain on the HRQoL of patients with PNP. NHP had a lower reliability but has other advantages that might be of importance. Many patients experienced poor pain relief from ongoing pain treatments. Most previous treatments were discontinued owing to lack of efficacy and/or severe side-effects. Many patients experienced a high intensity of at least one type of pain; median VAS for the highest pain intensity score of each patient (any type of pain) was 74/100. Besides pain, patients were most bothered by difficulty in sleeping, lack of energy, drowsiness, difficulty in concentrating and dry mouth. Employment status was reduced owing to pain in 52% of the patients. The intense pain, other troublesome symptoms, limited efficacy and tolerability of available treatments, together with the impaired health and reduced work status, amount to a substantial burden for patients with PNP.

A comparison of the SF-36 and Nottingham Health Profile in patients with chronic neuropathic pain

The aim of this study was to evaluate and compare the psychometric properties of two generic health-related quality of life (HRQoL) instruments, the Short Form Health Survey (SF-36) and the Nottingham Health Profile (NHP) in a group of patients with chronic peripheral neuropathic pain (PNP). The sample consisted of 126 adults (56 men and 70 women) with PNP following a lesion of a peripheral nerve, spinal nerve or nerve root or patients with post-herpetic neuralgia. The battery of tests included visual analogue scales (VASs) for pain assessment and global rating of health and verbal rating scales of pain and other symptoms, as well as patient descriptors. The SF-36 had higher internal consistency reliability coefficients (alpha=0.79, range 0.70-0.90) than the NHP (alpha=0.68, range 0.49-0.79). Correlations between comparable dimensions of the two instruments were significant (range from -0.79 for the physical and mental dimensions to -0.29 for the social dimension) indicating a moderate degree of convergent validity. The study population had significantly worse scores on all dimensions of the two instruments when compared with the general population. Subjects with high VAS scores for pain on movement and those with low global health ratings had poorer scores on the both instruments. Overall, the SF-36 performed somewhat better on psychometric testing than did the NHP. However, the NHP contains dimensions such as sleep and more pain items which might be of particular importance in the PNP population. Since the instruments are short, both could be retained for continued testing in outcome studies of this population.

Detection of Staphylococcus aureus infection by enzyme-linked immunosorbent assay and immunoblotting, using high molecular weight staphylococcal proteins

Two high molecular weight staphylococcal proteins, fibronectin-binding protein and a Mr 200,000 protein, were investigated as antigens for serodiagnosis of staphylococcal infections. Sera from patients with staphylococcal infections and from controls were subjected to immunoblot analysis with staphylococcal lysate proteins to identify staphylococcal antigens to which patients with staphylococcal infections specifically exhibited antibodies. One such protein was found in the Mr 200,000 region. This protein was purified and used as antigen in ELISA and compared with other antigens, namely fibronectin-binding protein(s) (FNBP, Mr 185,000), alpha-toxin and teichoic acid. Sera from patients with staphylococcal infections contained antibodies to the high molecular weight proteins in higher titers than sera from patients with non-staphylococcal infections or healthy subjects. Based on their amino-acid compositions and different abilities to bind fibronectin it was concluded that the Mr 200,000 protein and FNBP were not identical.