The latest medical research on Anesthesiology

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Anesthesia-induced Lymphatic Dysfunction.

Anesthesiology

General anesthetics adversely alters the distribution of infused fluid between the plasma compartment and the extravascular space. This maldistribu...

Advanced life support interventions during intra-operative cardiac arrest among adults as reported to the 7th National Audit Project of the Royal College of Anaesthetists.

Anaesthesia

Few existing resuscitation guidelines include specific reference to intra-operative cardiac arrest, but its optimal treatment is likely to require some adaptation of standard protocols.

We analysed data from the 7th National Audit Project of the Royal College of Anaesthetists to determine the incidence and outcome from intra-operative cardiac arrest and to summarise the advanced life support interventions reported as being used by anaesthetists.

In the baseline survey, > 50% of anaesthetists responded that they would start chest compressions when the non-invasive systolic pressure was < 40-50 mmHg. Of the 881 registry patients, 548 were adult patients (aged > 18 years) having non-obstetric procedures under the care of an anaesthetist, and who had arrested during anaesthesia (from induction to emergence). Sustained return of spontaneous circulation was achieved in 425 (78%) patients and 338 (62%) were alive at the time of reporting. In the 365 patients with pulseless electrical activity or bradycardia, adrenaline was given as a 1 mg bolus in 237 (65%). A precordial thump was used in 14 (3%) patients, and although this was associated with return of spontaneous circulation at the next rhythm check in almost three-quarters of patients, in only one of these was the initial rhythm shockable. Calcium (gluconate or chloride) and 8.4% sodium bicarbonate were given to 51 (9%) and 25 (5%) patients, but there were specific indications for these treatments in less than half of the patients. A thrombolytic drug was given to 5 (1%) patients, and extracorporeal cardiopulmonary resuscitation was used in 9 (2%) of which eight occurred during cardiac procedures.

The specific characteristics of intra-operative cardiac arrest imply that its optimal treatment requires modifications to standard advanced life support guidelines.

Accuracy and Precision of Three Acceleromyographs, Three Electromyographs and a Mechanomyograph Measuring the Train-of-Four Ratio in the Absence of Neuromuscular Blocking Drugs.

Anesthesiology

The accuracy and precision of currently available, widely used acceleromyograph and electromyograph neuromuscular blockade monitors have not been well studied. In addition, the normalization of the train-of-four ratio from acceleromyography (train-of-four ratio [T4/T1] divided by the baseline train-of-four ratio) has not been validated in comparison to mechanomyography.

Enrolled patients had surgery under general anesthesia with a supraglottic airway and without any neuromuscular blocking drugs. Three acceleromyograph monitors, three electromyograph monitors and a mechanomyograph built in our laboratory were tested. Most patients had an electromyograph and the mechanomyograph on one arm and a third monitor on the contralateral arm. Train-of-four ratios were collected every 12-20 seconds for the duration of the anesthetic. At least 1,000 train-of-four ratios were recorded for each device. Gauge repeatability and reproducibility analysis was performed.

Twenty-eight patients were enrolled. In total, 9,498 train-of-four ratio measurements were collected. Since no neuromuscular blocking drugs were used, the expected train-of-four ratio was 1.0. All of the acceleromyograph monitors produced overshoot in the train-of-four ratio (estimated means 1.10-1.13) and substantial variability (gauge standard deviations 0.07-0.18). Normalization of the train-of-four ratio measured by acceleromyography improved the estimated mean for each device (0.97-1.0) but the variability was not improved (gauge standard deviations 0.06-0.17). The electromyograph and the mechanomyograph monitors produced minimal overshoot (estimated means 0.99-1.01) and substantially less variation (gauge standard deviations 0.01-0.02). For electromyography and mechanomyography, 0.3% of all train-of-four ratios were outside of the range of 0.9-1.1. For acceleromyography, 27% to 51% of normalized train-of-four ratios were outside of the range of 0.9-1.1.

Three currently available acceleromyograph monitors produced overshoot and substantial variability that could be clinically significant. Normalization corrected the overshoot in the average results but did not reduce the wide variability. Three electromyograph monitors measured the train-of-four ratio with minimal overshoot and variability, similar to a mechanomyograph.

A Practical Dosing Algorithm for Deep Neuromuscular Blockade During Total Intravenous Anesthesia: ROCURITHM.

Anesthesiology

The number of trials investigating the effects of deep neuromuscular blockade (NMB) on surgical conditions and patient outcomes is steadily increasing. Consensus on which surgical procedures benefit from deep NMB (a post tetanic count of 1-2) and how to implement it has not been reached. The ESAIC does not advise routine application but recommends use of deep NMB to improve surgical conditions on indication. This study investigates the optimal dosing strategy to reach and maintain adequate deep NMB during total intravenous anesthesia.

Data from three trials investigating deep NMB during laparoscopic surgery with TIVA (n=424) was pooled to analyze the required rocuronium dose, when to start continuous infusion and how to adjust. The resulting algorithm was validated (n=32) and compared to the success rate in ongoing studies where the algorithm was not used (n=180).

The mean rocuronium dose based on actual bodyweight for PTC 1-2 was 1.0 ± 0.27 mg.kg -1.h -1 in the trials where mean duration of surgery was ±2 hours (116 minutes). An induction dose of 0.6 mg.kg -1 lead to a PTC of 1-5 in a quarter of patients after a mean of 11 minutes. The remaining patients were equally divided over too shallow (additional bolus and direct start of continuous infusion) or too deep; a ±15-minute wait after PTC 0 for return of PTC to ≥1. Using the proposed algorithm, a mean 76% of all 5-minute measurements throughout surgery were on target PTC 1-2 in the validation cohort. The algorithm performed significantly better than anesthesiology residents without the algorithm, even after a learning curve from 0-20 patients (42% on target, P≤.001, Cohen's d=1.4 [95% CI 0.9, 1.8]) to 81-100 patients (61% on target, P≤.05, Cohen's d=0.7 [95% CI 0.1, 1.2]).

We propose a dosing algorithm for deep NMB with rocuronium in patients receiving TIVA.

Perioperative Acute Renal Injury: Revisiting Pathophysiology.

Anesthesiology

Acute renal dysfunction and subsequent acute renal failure after cardiac surgery are associated with high mortality and morbidity. Early therapeutic or preventive intervention is hampered by the lack of an early biomarker for acute renal injury. Recent studies showed that urinary neutrophil gelatinase-associated lipocalin (NGAL or lipocalin 2) is upregulated early (within 1 to 3 h) after murine renal injury and in pediatric acute renal dysfunction after cardiac surgery. The authors hypothesized that postoperative urinary NGAL concentrations are increased in adult patients developing acute renal dysfunction after cardiac surgery compared with patients without acute renal dysfunction.

After institutional review board approval, 81 cardiac surgical patients were prospectively studied. Urine samples were collected immediately before incision and at various time intervals after surgery for NGAL analysis by quantitative immunoblotting. Acute renal dysfunction was defined as peak postoperative serum creatinine increase by 50% or greater compared with preoperative serum creatinine.

Sixteen of 81 patients (20%) developed postoperative acute renal dysfunction, and the mean urinary NGAL concentrations in patients who developed acute renal dysfunction were significantly higher early after surgery (after 1 h, mean ± SD, 4,195±6,520 vs. 1,068±2,129ng/ml; P < 0.01) compared with patients who did not develop acute renal dysfunction. Mean urinary NGAL concentrations continued to increase and remained significantly higher at 3 and 18 h after cardiac surgery in patients with acute renal dysfunction. In contrast, urinary NGAL in patients without acute renal dysfunction decreased rapidly after cardiac surgery.

Patients developing postoperative acute renal dysfunction had significantly higher urinary NGAL concentrations early after cardiac surgery. Urinary NGAL may therefore be a useful early biomarker of acute renal dysfunction after cardiac surgery. These findings may facilitate the early detection of acute renal injury and potentially prevent progression to acute renal failure.

Patterns of opioid use after surgical discharge: a multicentre, prospective cohort study in 25 countries.

Anaesthesia

Excessive opioid prescribing following surgery contributes to the growing opioid crisis. Prescribing practices are modifiable, yet data to guide appropriate prescription of opioids at surgical discharge remain sparse. This study aimed to evaluate factors associated with opioid consumption following discharge from surgery.

An international prospective multicentre cohort study was performed recruiting adult patients undergoing common general, orthopaedic, gynaecological and urological surgery, with follow-up 7 days after discharge. The primary outcome measures were the quantities of prescribed and consumed opioids in oral morphine milligram equivalents. Descriptive and multivariable analyses were performed to investigate factors associated with the primary outcome measures.

This analysis included 4273 patients from 144 hospitals in 25 countries. Overall, 1311 (30.7%) patients were prescribed opioids at discharge. For those patients prescribed opioids, mean (SD) 179 (240) oral morphine milligram equivalents were prescribed, yet only 81 (145) oral morphine milligram equivalents were consumed within the first 7 days after discharge. An increased dose of opioids prescribed at discharge was associated with an increased dose of opioids consumed during the follow-up period (β = 0.33 (95%CI 0.31-0.34), p < 0.001). The risk of prescribing more opioids than patients consumed increased as quantities of opioids prescribed at discharge exceeded 100 oral morphine milligram equivalents, independent of patient comorbidity, procedure and pain. Patients were prescribed more than twice the quantity of opioids they consumed in the first 7 days following discharge from surgery.

Our data suggest that the current quantities of opioids provided at discharge exceed patient needs and may contribute to increasing community opioid use and circulation.

Electroencephalographic indices for clinical endpoints during propofol anesthesia in infants-an early phase propofol biomarker-finding study.

Anesthesiology

Unlike expired sevoflurane concentration, propofol lacks a biomarker for its brain effect site concentration (Ce), leading to dosing imprecision particularly in infants. Electroencephalography (EEG) monitoring can serve as a biomarker for propofol Ce, yet proprietary EEG indices are not validated in infants. We evaluated spectral edge frequency (SEF95) as a propofol anesthesia biomarker in infants. We hypothesized that the SEF95 targets will vary for different clinical stimuli and an inverse relationship existed between SEF95 and propofol plasma concentration.

This prospective study enrolled infants (3-12 months) to determine the SEF95 ranges for three clinical endpoints of anesthesia (consciousness-pacifier placement, pain-electrical nerve stimulation, and intubation-laryngoscopy) and correlation between SEF95 and propofol plasma concentration at steady state. Dixon's Up-Down method was used to determine target SEF95 for each clinical endpoint. Centered isotonic regression determined the dose-response function of SEF95 where 50% and 90% of infants (ED50 and ED90) did not respond to the clinical endpoint. Linear mixed-effect model determined the association of propofol plasma concentration and SEF95.

Of 49 enrolled infants, 44 evaluable (90%) showed distinct SEF95 for endpoints: pacifier (ED50 21.4Hz, ED90 19.3Hz), electrical stimulation (ED50 12.6Hz, ED90 10.4Hz), and laryngoscopy (ED50 8.5Hz, ED90 5.2Hz). From propofol 0.5-6 μg/ml, a 1 Hz SEF95 increase was linearly correlated to a 0.24 (95% CI: 0.19 - 0.29, p<0.001) μg/mL decrease in plasma propofol concentration (marginal R 2 = 0.55).

SEF95 can be a biomarker for propofol anesthesia depth in infants, potentially improving dosing accuracy and utilization of propofol anesthesia in this population.

Opioid analgesic exposure during the first trimester of pregnancy and the risk of major congenital malformations in infants: a systematic review and meta-analysis†.

Anaesthesia

Prescribed opioid analgesics are frequently used to manage pain in pregnancy. However, the available literature regarding the teratogenic potential of opioid use during pregnancy has not been systematically summarised. This systematic review and meta-analysis aimed to assess the quality of the evidence on these potential risks and calculate a pooled estimate of risk for any opioid analgesic and individual opioids.

We searched PubMed, Embase and CINAHL for published studies assessing the risk of major congenital malformations in infants following first-trimester exposure to opioid analgesics compared with a reference group, excluding studies examining opioid agonist therapy or illicit opioid use. We assessed the risk of bias using the Risk of Bias in Non-Randomised Studies of Intervention tool. We pooled adjusted risk estimates from studies rated at serious risk of bias or better in a random-effects meta-analysis.

Of 12 identified studies, 11 were at high risk of bias (eight serious; three critical). Relative to unexposed infants, those exposed to any opioid use during the first trimester of pregnancy were not at an increased risk of major congenital malformations overall (relative risk 1.04, 95%CI 0.98-1.11); cardiovascular malformations (relative risk 1.07, 95%CI 0.96-1.20); or central nervous system malformations (relative risk 1.06, 95%CI 0.92-1.21). Raised risk estimates were observed for gastrointestinal malformations (relative risk 1.40, 95%CI 0.38-5.16) and cleft palate (relative risk 1.57, 95%CI 0.48-5.13) following any opioid exposure and atrial septal defects (relative risk 1.20, 95%CI 1.05-1.36) following codeine exposure.

Although the meta-analysis did not indicate substantial increased risk for most malformations examined, this risk remains uncertain due to the methodological limitations of the included studies. Healthcare professionals and pharmaceutical regulators should be aware of the issues related to the quality of research in this field.

Totally implanted central venous access devices inserted by the femoral route: A narrative review and the proposal of a novel approach, the FICC-port.

J Vasc Access

Femoral ports are used in patients with indication to a totally implanted venous access device but with contraindication to chest-ports and brachial ports because of obstruction of the superior vena cava. In the last three decades, femoral ports have been implanted almost exclusively by cannulation of the common femoral vein at the groin, while the position of the tip has been assessed by X-ray.

We report our experience with a new approach to femoral ports, which includes recent methods and techniques developed in the last few years. These novel femoral ports, which we call "FICC-ports," are characterized by (a) long femoral 5 Fr polyurethane catheter inserted by ultrasound-guided puncture of the superficial femoral vein at mid-thigh; (b) intraprocedural location of the tip in the sub-diaphragmatic inferior vena cava, using ultrasound visualization by the transhepatic and/or the subcostal view; (c) low-profile or very low-profile reservoir implanted above the quadriceps muscle, at mid-thigh.

In the last 3 years, we have implanted 47 FICC-ports in young adults with mediastinal lymphoma compressing the superior vena cava. We had no immediate/early complication, and only three late complications (one kinking of the catheter in the subcutaneous tissue; one tip migration with secondary venous thrombosis; one persistent withdrawal occlusion due to fibroblastic sleeve).

If there is indication to a femoral port, the implantation of a "FICC-port"-as described above-is to be strongly considered in terms of safety, effectiveness, and cost-effectiveness: no immediate-early complications, minimal late complications, no X-ray exposure, low invasiveness, low cost.

Snuffbox distal transradial access (dTRA) for arteriovenous fistuloplasty in Singapore: Going distal is safe.

J Vasc Access

Arteriovenous fistula (AVF) dysfunction resulting from stenosis or occlusion, is a prevalent issue in end-stage renal failure patients reliant on autogenous AVFs for dialysis. Recently, a distal transradial approach (dTRA) has emerged, offering advantages such as diminished access site complications, better patient comfort and reduced risk of radial artery occlusion. Our study seeks to assess the effectiveness, outcomes and complication rates of employing dTRA for arteriovenous fistuloplasty in Singaporean patients.

A retrospective review of all dTRA fistuloplasties performed on dysfunctional or slow to mature AVFs from 2017 to 2023 in our institution was performed. Patients with a distal radial artery measuring 2 mm or more with no evidence of occlusion or thrombosis were included. Patients who required central venoplasty or cutting balloon angioplasty were excluded. Outcome measures included technical success, mean procedure duration, complications and post-intervention primary patency at 1, 3 and 6 months. Patients were followed up for 12 months post-intervention.

A total of 37 patients were included. 97.3% of patients undergoing dTRA fistuloplasty had radiocephalic fistulas while 2.7% had brachiobasilic fistulas. There was 100% technical success (defined as success in radial artery cannulation, sheath insertion and crossing of stenotic lesions) in our study as all patients successfully underwent fistuloplasty via dTRA approach. One-month patency rate was 97.4%, 3-month patency rate was 92.1% and 6-month patency rate was 86.8%. There were no immediate complications (haematoma, infection, bleeding, pseudoaneurysm, occlusion) of the radial artery post-intervention.

Our paper illustrates the safety and efficacy of utilising dTRA for arteriovenous fistuloplasty. This approach offers distinct benefits in addressing non-mature or dysfunctional distal forearm arteriovenous fistulas and should be taken into account in anatomically suitable cases.

The influence of near-infrared therapy on arteriovenous fistula patency in haemodialysis patients: A multicentre, randomised, controlled clinical trial.

J Vasc Access

Arteriovenous fistula (AVF) is the preferred vascular access for patients undergoing haemodialysis (HD). AVF malfunction remains a major clinical problem and is a significant independent risk factor for death. Although far-infrared (FIR) therapy has been shown to reduce complications and improve the patency rate of AVFs in various studies, it has been cautiously recommended by the Kidney Disease Outcome Quality Initiative (KDOQI) guidelines for AVF care due to insufficient evidence. Therefore, it is necessary to identify more effective methods for preventing AVF dysfunction. Many in vitro studies and few clinical studies have examined the effects of near-infrared (NIR) therapy on the vasculature. This study will examine the effects of NIR therapy on AVF.

A randomised, controlled, open-label, multicentre trial will compare the effect of NIR on AVF patency after 1 year of therapy with that of a control group of patients with existing AVF. One group of patients received NIR treatment above their AVFs, whereas the control group received regular care. The primary outcome is the primary fistula patency rate within 12 months. In addition, acute changes in inflammatory, vasodilatory and haemodynamic parameters after a single treatment in the first 40 participants will be examined. This study was registered in the Clinical Trials Registry (ChiCTR2300071305) at https://register.clinicaltrials.gov/.

This study will explore the long-term and acute effects of NIR on AVFs. The study findings will provide information that can be used to develop new technical support for the prevention of AVF dysfunction in patients undergoing haemodialysis.

Cavoatrial junction stenting in vascular hemodialysis catheter malfunction.

J Vasc Access

In patients undergoing hemodialytic treatment via intravascular catheters, stenosis or occlusion of central veins is common. Despite an extensive c...