Comparing Continuous and Intermittent Infusion Effects on Serratus Anterior Plane Blocks in Video-Assisted Thoracoscopic Surgery: A Randomized Clinical Trial.

Objective: The programmed intermittent bolus infusion (PIBI) of local anesthetic produces wider sensory blockade and better analgesia than continuous infusion (CI). We designed this trial to compare the effects of these two different infusion methods combined with Serratus Anterior Plane Blocks (cSAPBs) on postoperative pain relief in patients undergoing video-assisted thoracoscopic surgery. Methods: We randomly allocated 66 patients under going elective video-assisted thoracoscopic unilateral lung resection surgery to two groups (PIBI group and CI group, n=33 per group). After the surgical operation, the patients received ultrasound-guided ipsilateral SAPB, we randomized them to receive either automated intermittent boluses or continuous infusion of 0.3% ropivacaine. Tramadol consumption during the 48 hours following surgery was the primary outcome. Secondary outcomes included cumulative tramadol consumption during the first 24-h and the second 24-h periods after surgery, pain scores, patient satisfaction, blocked dermatomes, and adverse events. Results: During 48h, tramadol consumption in the PIBI group was significantly lower than in the CI group (190 mg [125, 305] vs 220 mg [170, 480], p= 0.034). As compared to the CI group, the PIBI group consumed less tramadol during the first 24 hours (145 mg [87.5, 210] vs 190 mg [140, 400], p=0.012). The dermatomes anesthetized to the pinprick and cold test were significantly more abundant in the PIBI group than in the CI group (3 [3,4] vs. 5 [4,5], p<0.001). Both groups had similar VAS scores at rest and when moving (p>0.05). Additionally, the PIBI group showed greater patient satisfaction. Both groups experienced similar adverse events (p>0.05). Conclusion: Compared with CI, PIBI administration regimen (0.3% ropivacaine 5 mL/h) for cSAPBs resulted in lower tramadol consumption, superior analgesia during the initial 12 h after the operation, and higher patient satisfaction. PIBI combined with cSAPBs was a better choice for postoperative analgesia in patients undergoing video-assisted thoracoscopic surgery.

Evaluating infusion methods and simplified quantification of synaptic density in vivo with [11C]UCB-J and [18F]SynVesT-1 PET.

For some positron emission tomography studies, radiotracer is administered as bolus plus continuous infusion (B/I) to achieve a state of equilibrium. This approach can reduce scanning time and simplify data analysis; however, the method must be validated and optimized for each tracer. This study aimed to validate a B/I method for in vivo quantification of synaptic density using radiotracers which target the synaptic vesicle glycoprotein 2 A: [11C]UCB-J and [18F]SynVesT-1. Observed mean standardized uptake values (SUV) in target tissue relative to that in plasma (CT/CP) or a reference tissue (SUVR-1) were calculated for 30-minute intervals across 120 or 150-minute dynamic scans and compared against one-tissue compartment (1TC) model estimates of volume of distribution (VT) and binding potential (BPND), respectively. We were unable to reliably achieve a state of equilibrium with [11C]UCB-J, and all 30-minute windows yielded overly large bias and/or variability for CT/CP and SUVR-1. With [18F]SynVesT-1, a 30-minute scan 90-120 minutes post-injection yielded CT/CP and SUVR-1 values that estimated their respective kinetic parameter with sufficient accuracy and precision (within 7±6%) . This B/I approach allows a clinically feasible scan at equilibrium with potentially better accuracy than a static scan SUVR following a bolus injection.

Effectiveness of Extended or Continuous vs. Bolus Infusion of Broad-Spectrum Beta-Lactam Antibiotics for Febrile Neutropenia: A Systematic Review and Meta-Analysis.

This systematic review aimed to compare extended infusion or continuous infusion with bolus infusion for febrile neutropenia (FN). We included clinical trials comparing extended or continuous infusion with bolus infusion of beta-lactam antibiotics as empirical treatment for FN and evaluated the clinical failure, all-cause mortality, and adverse event rates. Five articles (three randomized controlled trials (RCTs) and two retrospective studies) from 2014 to 2022 were included. Clinical failure was assessed with a risk ratio (RR) (95% coincident interval (CI)) of 0.74 (0.53, 1.05) and odds ratio (OR) (95% CI) of 0.14 (0.02, 1.17) in the 2 RCTs and retrospective studies, respectively. All-cause mortality was assessed with an RR (95% CI) of 1.25 (0.44, 3.54) and OR (95% CI) of 1.00 (0.44, 2.23) in the RCTs and retrospective studies, respectively. Only 1 RCT evaluated adverse events (with an RR (95% CI) of 0.46 (0.13, 1.65)). The quality of evidence was "low" for clinical failure and all-cause mortality in the RCTs. In the retrospective studies, the clinical failure and all-cause mortality evidence qualities were considered "very low" due to the study design. Extended or continuous infusion of beta-lactam antibiotics did not reduce mortality better than bolus infusion but was associated with shorter fever durations and fewer adverse events.

A prospective double-blinded randomized control trial comparing erector spinae plane block to thoracic epidural analgesia for postoperative pain in video-assisted thoracic surgery.

OBJECTIVES: To compare the analgesic efficacies of erector spinae plane (ESP) block and thoracic epidural analgesia (TEA) in video-assisted thoracic surgery (VATS). METHODS: Sixty patients undergoing VATS received patient-controlled TEA with a basal rate of 3 ml/hour (h), a bolus of 3 ml (Group E), or ESP block with programmed intermittent bolus infusions of 15 mL/3 h and a bolus of 5 ml (Group ES) for 2 postoperative days. The primary outcome was to compare pain scores at rest 24 h postoperatively between the 2 groups. Secondary outcomes included NRS score for 48 h, procedural time, dermatomal spread, use of rescue medication, adverse events, and patient satisfaction. RESULTS: Patients with continuous ESP block had a higher NRS score than those with TEA but no statistical difference at a specific time. The dermatomal spread was more extensive in the TEA group than in the ESP block group (p=0.016); cumulative morphine consumption was higher in the ESP block group (p=0.047). The incidence of overall adverse events in the TEA group was higher than in the ESP block group (p=0.045). CONCLUSION: Erector spinae plane block may be inferior to TEA for analgesia following VATS, but it could have tolerable analgesia and a better side effect profile than TEA. Therefore, it could be an alternative to TEA as a component of multimodal analgesia.

Factors associated with the decision to administer ß-lactams via prolonged infusion in patients with sepsis: a prospective observational cohort study.

OBJECTIVE: ß-lactams are the most widely used antibiotics in sepsis. We aimed to explore the factors that drive physicians to choose prolonged infusion (PI) of ß-lactams in septic patients. METHODS: This prospective observational national cohort study was conducted in 40 ICUs at the teaching hospitals of 31 provinces in China between August 20, 2021 and September 20, 2021. RESULTS: Of the 441 enrolled patients, 265 (60.09%) received PI therapy. Multivariate analysis showed that multidrug-resistant bacterial infection and septic shock were independent factors associated with PI. However, our data showed that the survival benefit of PI use was evident in subgroups with less severe sepsis, including those with lower Charlson comorbidity index values (<2), those without septic shock, and those with lower acute physiology and chronic health evaluation II scores (<15). Univariate and multivariate Cox regression indicated that PI was an independent protective factor of 28d mortality, even after adjusting the variables associated with disease severity. CONCLUSIONS: PI for administering ß-lactams was not a commonly applied strategy in sepsis and was more likely to be used in severely ill patients. However, PI had a survival benefit independent of disease severity.

The Effects of Programmed Intermittent Paravertebral Bolus Infusion on Postoperative Analgesia in Patients Undergoing Video-Assisted Thoracoscopic Surgery: A Prospective, Randomized, Controlled Study.

OBJECTIVES: To compare the effects of programmed intermittent bolus infusion (PIBI), continuous thoracic paravertebral infusion (CTPI), and continuous intravenous infusion (CII) on postoperative analgesia in patients undergoing video-assisted thoracoscopic surgery (VATS). DESIGN: Prospective, randomized, controlled. SETTING: The operating room, post-anesthesia care unit, and patient ward of a university hospital. PARTICIPANTS: Ninety patients with American Society of Anesthesiologists (ASA) physical status Ι to II, aged 35-70 years, and scheduled for VATS. INTERVENTIONS: Postoperative analgesia was randomized to PIBI, CTPI, and CII. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the numeric rating scale (NRS) score at rest and during coughing at 1, 4, 24, and 48 hours after surgery. The secondary outcomes included the actual and effective numbers of patient-controlled analgesia (PCA), ropivacaine use, Ramsay sedation scale score, quality of recovery-15 (QoR-15) score, values of hemodynamic parameters at different periods, intraoperative consumption of anesthetic drugs, and postoperative adverse events. Postoperatively, the NRS score was reduced in the PIBI group compared with the CTPI and CII groups at rest and during coughing (p < 0.05). The number of PCAs was significantly lower in the PIBI group compared with the CTPI and CII groups (p < 0.05). The QoR-15 score noticeably increased in the PIBI group compared with the CTPI and CII groups (p = 0.001 and p = 0.000, respectively). CONCLUSIONS: PIBI outperformed CTPI and CII in inducing analgesia for postoperative pain in patients undergoing VATS.

Effects of Different 0.2% Ropivacaine Infusion Regimens for Continuous Interscalene Brachial Plexus Block on Postoperative Analgesia and Respiratory Function After Shoulder Arthroscopic Surgery: A Randomized Clinical Trial.

Objective: Continuous interscalene brachial plexus block (cIBPB) is an effective perioperative analgesic therapy for shoulder arthroscopic surgery (SAS) patients. This trial aimed to compare the effect of different cIBPB infusion methods on postoperative analgesia and respiratory function in patients undergoing SAS. Methods: After SAS, 88 patients were randomly assigned to four groups. Through interscalene catheter, all the patients received an initial dose of 10 mL 0.2% ropivacaine. The CI group received 0.2% ropivacaine 4 mL/h, and the PIBI1, PIBI2, and PIBI3 groups received intermittent 0.2% ropivacaine boluses at 4 mL/h, 8 mL/2 h, and 12 mL/3 h, respectively. The patients could also use a patient-controlled analgesia (PCA) pump to self-inject a tramadol bolus each time he/she felt pain. The primary outcome was the cumulative tramadol consumption over the 48 h after surgery. Secondary outcome measures included PCA frequency, pain (visual analogue scale, VAS) score, patient satisfaction, diaphragmatic excursion, pulmonary function, and adverse events. Results: The cumulative tramadol consumption and PCA frequency over the 48 h after surgery in groups PIBI2 and PIBI3 were lower than in both the CI and PIBI1 groups (p<0.001). The VAS scores (at rest and on movement) in groups PIBI2 and PIBI3 were lower than those in the CI and PIBI1 groups at 8 and 12 h after surgery (all p<0.001). Patient satisfaction scores were significantly higher in the PIBI2 group than in the other three groups (all p<0.001). Diaphragmatic excursion was significantly decreased in the PIBI3 group compared to the other three groups (p<0.05). The incidence of adverse events over the 48 h after surgery was significantly higher in the PIBI3 group compared to the other three groups (p<0.001). Conclusion: Programmed intermittent bolus infusion with 0.2% ropivacaine 8 mL/2 h for cIBPB can achieve lower tramadol consumption, along with better analgesia after surgery, lower reduction in diaphragmatic excursion, lower incidence of adverse events, and higher patient satisfaction.

Intercompartmental communication between the cerebrospinal and adjacent spaces during intrathecal infusions in an acute ovine in-vivo model.

INTRODUCTION: The treatment of hydrocephalus has been a topic of intense research ever since the first clinically successful use of a valved cerebrospinal fluid shunt 72 years ago. While ample studies elucidating different phenomena impacting this treatment exist, there are still gaps to be filled. Specifically, how intracranial, intrathecal, arterial, and venous pressures react and communicate with each other simultaneously. METHODS: An in-vivo sheep trial (n = 6) was conducted to evaluate and quantify the communication existing within the cranio-spinal, arterial, and venous systems (1 kHz sampling frequency). Standardized intrathecal infusion testing was performed using an automated infusion apparatus, including bolus and constant pressure infusions. Bolus infusions entailed six lumbar intrathecal infusions of 2 mL Ringer's solution. Constant pressure infusions were comprised of six regulated pressure steps of 3.75 mmHg for periods of 7 min each. Mean pressure reactions, pulse amplitude reactions, and outflow resistance were calculated. RESULTS: All sheep showed intracranial pressure reactions to acute increases of intrathecal pressure, with four of six sheep showing clear cranio-spinal communication. During bolus infusions, the increases of mean pressure for intrathecal, intracranial, arterial, and venous pressure were 16.6 ± 0.9, 15.4 ± 0.8, 3.9 ± 0.8, and 0.1 ± 0.2 mmHg with corresponding pulse amplitude increases of 2.4 ± 0.3, 1.3 ± 0.3, 1.3 ± 0.3, and 0.2 ± 0.1 mmHg, respectively. During constant pressure infusions, mean increases from baseline were 14.6 ± 3.8, 15.5 ± 4.2, 4.2 ± 8.2, and 3.2 ± 2.4 mmHg with the corresponding pulse amplitude increases of 2.5 ± 3.6, 2.5 ± 3.0, 7.7 ± 4.3, and 0.7 ± 2.0 mmHg for intrathecal, intracranial, arterial, and venous pulse amplitude, respectively. Outflow resistances were calculated as 51.6 ± 7.8 and 77.8 ± 14.5 mmHg/mL/min for the bolus and constant pressure infusion methods, respectively-showing deviations between the two estimation methods. CONCLUSIONS: Standardized infusion tests with multi-compartmental pressure recordings in sheep have helped capture distinct reactions between the intrathecal, intracranial, arterial, and venous systems. Volumetric pressure changes in the intrathecal space have been shown to propagate to the intraventricular and arterial systems in our sample, and to the venous side in individual cases. These results represent an important step into achieving a more complete quantitative understanding of how an acute rise in intrathecal pressure can propagate and influence other systems.

Bolus infusion scheme for the adjustment of steady state [11C]Flumazenil levels in the grey matter and in the blood plasma for neuroreceptor imaging.

The use of hybrid PET/MR imaging facilitates the simultaneous investigation of challenge-related changes in ligand binding to neuroreceptors using PET, while concurrently measuring neuroactivation or blood flow with MRI. Having attained a steady state of the PET radiotracer using a bolus-infusion protocol, it is possible to observe alterations in ligand neuroreceptor binding through changes in distribution volumes. Here, we present an iterative procedure for establishing an administration scheme to obtain steady state [11C]flumazenil concentrations in grey matter in the human brain. In order to achieve a steady state in the shortest possible time, the bolus infusion ratio from a previous examination was adapted to fit the subsequent examination. 17 male volunteers were included in the study. Boli and infusions with different weightings were given to the subjects and were characterised by kbol values from 74 â€‹min down to 42 â€‹min. Metabolite analysis was used to ascertain the value of unmetabolised flumazenil in the plasma, and PET imaging was used to assess its binding in the grey matter. The flumazenil time-activity curves (TACs) in the brain were decomposed into activity contributions from pure grey and white matter and analysed for 12 â€‹vol of interest (VOIs). The curves highlighted a large variability in metabolic rates between the subjects, with kbol â€‹= â€‹54.3 â€‹min being a reliable value to provide flumazenil equilibrium conditions in the majority of the VOIs and cases. The distribution volume of flumazenil in all 12 VOIs was determined.

Comparison of bolus versus continuous infusion of propofol for procedural sedation: a meta-analysis.

OBJECTIVE: To compare the efficacy and safety of bolus infusion versus continuous infusion for propofol sedation. METHODS: We searched OVID-MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), Google Scholar, Koreamed, and Kmbase databases to identify all randomized controlled trials that compared bolus infusion with continuous infusion for propofol sedation. We evaluated propofol dose used, procedure, sedation, and recovery time. The incidences of respiratory and cardiovascular complications were also evaluated. RESULTS: A total of 12 studies of 963 patients were included. The required propofol dose was significantly higher in continuous infusion compared with bolus infusion (standardized mean difference [SMD]: -0.44; 95% confidence interval [CI]: -0.71 to -0.16; I2 = 84%). Sedation time was significantly longer in continuous infusion compared with bolus infusion (mean difference [MD]: -8.58 min; 95% CI: -15.13 to -2.03; I2 = 44%). The recovery time and incidences of desaturation, airway intervention, hypotension, and bradycardia were comparable between bolus and continuous infusion. CONCLUSIONS: Propofol sedation by continuous infusion required a higher dose of propofol compared with bolus infusion, but the recovery time and frequency of complications were similar.

Comparison of the Effects of Intermittent Boluses to Simple Continuous Infusion on Patients' Global Perceived Effect in Intrathecal Therapy for Pain: A Randomized Double-Blind Crossover Study.

Objective: Intrathecal drug delivery (ITDD) is commonly used for intractable pain management. A paucity of good-quality studies in chronic noncancer patients and concerns over increased dosages have focused interest on different modes of administration. The aim of this international multicenter randomized double-blind crossover trial was to compare the efficacy of the same daily dose of drugs administered by intermittent boluses vs simple continuous infusion. Methods: Eligible patients implanted with a programmable ITDD device were randomized to receive two weeks of either intermittent boluses or a simple continuous flow in period 1, followed by a crossover to the alternative mode of administration. The primary outcome measure was the Patients' Global Impression of Change (PGIC) scale. Results: The mean proportion of positive responders (at least "minimally improved") was 38.4% in the continuous condition vs 37.3% in the bolus (difference in proportions = 1.1%, 95% confidence interval [CI] = -21.8-24.0%, P = 0.93). The mean PGIC in the continuous condition was 3.8 vs 3.9 in the bolus (mean difference = -0.1, -0.6-0.4, P = 0.72). Exploratory analyses revealed a tendency for the mean proportion of positive responders to be higher at low vs high flow rates for both bolus and continuous administrations. Two patients were withdrawn from the study due to adverse events during the bolus phase, both with symptoms of increased pain, and one patient with additional symptoms of numbness and urinary retention. Conclusion: The mean PGIC and proportion of positive responders was not substantially different after intermittent bolus vs continuous administration.

Associations between bolus infusion of hydrocortisone, glycemic variability and insulin infusion rate variability in critically Ill patients under moderate glycemic control.

BACKGROUND: We retrospectively studied associations between bolus infusion of hydrocortisone and variability of the blood glucose level and changes in insulin rates in intensive care unit (ICU) patients. METHODS: 'Glycemic variability' and 'insulin infusion rate variability' were calculated from and expressed as the standard deviation (SD) of all blood glucose levels and insulin infusion rates during stay in the ICU, respectively. Glycemic and insulin infusion rate variability in patients who received bolus infusion of hydrocortisone were compared to those in patients who never received bolus infusion of hydrocortisone. Multivariate analysis was performed to correct for potential covariates including disease severity. RESULTS: We included 6409 patients over 6 years; of them 962 received bolus infusion of hydrocortisone. Compared to patients who never received bolus infusion of hydrocortisone, patients who received hydrocortisone had their blood glucose level measured more frequently, had higher glycemic variability; were more frequently treated with intravenous insulin and had higher insulin infusion rate variability. The association between hydrocortisone treatment and glycemic variability was independent of disease severity, but the effect of hydrocortisone treatment on blood glucose variability was less strong in the more severely ill patients. The association between hydrocortisone and insulin infusion rate variability was also independent of disease severity, and independent of glycemic variability. CONCLUSIONS: Bolus infusion of hydrocortisone is independently associated with higher glycemic variability and higher insulin infusion rate variability in ICU patients. Studies are needed to see if continuous infusion of hydrocortisone prevents higher glycemic variability and higher insulin infusion rate variability.