Vasorelaxant effect of opioid analgesics on the isolated human radial artery

Effect of mild sedation and analgesia on radial artery cannulation in novice residents: a prospective, randomized controlled trial

BACKGROUND

Radial artery cannulation can be challenging, particularly for inexperienced providers. This study aimed to compare the success rates of resident physicians performing radial artery cannulation with mild sedation and analgesia versus without.

MATERIALS AND METHODS

This study was a prospective, single-center, double-blind randomized controlled trial. Twelve anesthesiology residents performed radial artery insertions on 96 patients. The procedures were conducted with either mild sedation and analgesia (treatment group) or an equivalent volume of 0.9%Nacl (control group), in a random order. The primary outcome was the success rate of radial artery cannulation within 10 min for each group. Secondary outcomes included the first-attempt success rate, visual analogue scale (VAS) scores, and self-reported patient discomfort scores (0 corresponding to "no anxious", 1 corresponding to "mildly anxious", 2 corresponding to "moderately anxious" and 3 corresponding to "very anxious").

RESULTS

The success rate of radial artery cannulation within 10 min was 75.0% (36/48) in the treatment group and 54.2% (26/48) in the control group, respectively (difference 20.8%; P = 0.033, OR: 1.38, 95%CI: 1.02-1.88). The first-attempt success rate was 68.8% (33/48) in the treatment group, compared to 52.1% (25/48) in the control group (difference 16.7%; P = 0.095, OR: 1.32, 95%CI: 0.95-1.84). The VAS scores and self-reported patient discomfort scores were significantly lower in the treatment group than in the control group (2.0 [2.0, 2.0] vs. 3.0 [2.0, 4.0], P = 0.005; 1.0 [0.0, 2.0] vs. 2.0 [2.0, 2.0], P<0.001, respectively).

CONCLUSIONS

The success rate of radial artery cannulation within 10 min significantly increased for anesthesiology residents with the use of mild sedation and analgesia. Additionally, these medications resulted in a notable reduction in procedure-related pain and patient discomfort.

TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov (NCT05863455), with Qing-he Zhou as the principal investigator, on May 16, 2023.

Flow-mediated dilation facilitates radial artery cannulation in patients undergoing intravenous general anesthesia: A prospective randomized controlled trial

BACKGROUND

Flow-mediated dilation (FMD) is commonly used as a diagnostic tool to assess endothelial function, and compared with other methods for stimulating radial artery dilation, FMD offers several advantages such as non-invasiveness, ease of execution, minimal equipment requirements, and negligible risk. The study aimed to investigate the effect of FMD in facilitating radial arterial cannulation in the context of intravenous general anesthesia.

METHODS

Eighty patients undergoing intravenous general anesthesia and requiring radial artery cannulation were randomized 1:1 to the FMD group and control group. Patients in the FMD group received an upper arm occlusion for 5 min after anesthesia induction, and the cuff was placed without inflation for the equivalent duration in the control group. The primary outcome was first-attempt success rate. Secondary outcomes were the diameter and percentage of dilation of radial artery, overall success rate, total number of attempts, cannulation time, and occurrence of procedure-related complications.

RESULTS

Intravenous anesthetic agents significantly dilated the radial artery (p < 0.05), which was further increased by FMD. An increase in both the first-attempt and overall success rate of radial artery cannulation was demonstrated with the use of FMD (67.5% vs 42.5%, p < 0.05). The total number of attempts needed to cannulate the radial artery was reduced in the FMD group as compared with the control group (p < 0.05), but no differences in cannulation time and procedure-related complications were found between the two groups (p > 0.05).

CONCLUSIONS

FMD induced by a 5-min upper arm occlusion may facilitate radial artery cannulation in patients undergoing intravenous general anesthesia.

Use of Fentanyl During Percutaneous Coronary Interventions: Safety and Drawbacks

Over the last years, fentanyl, a potent synthetic μ receptor-stimulating opioid, has become one of the most used drugs for both procedural analgesia and sedation in patients undergoing coronary angiography (CA) and/or percutaneous coronary intervention (PCI). However, few studies have been performed to evaluate the efficacy and the impact of this drug in patients with coronary artery disease (CAD) treated with PCI. Most of the previous studies have investigated the self-reported discomfort pain, demonstrating that patients premedicated with fentanyl generally reported a lower pain/discomfort when compared to placebo, benzodiazepines, or local anesthesia at the site of the artery cannulation, without significant variation in the hemodynamic response. The biochemical properties of fentanyl have been used to prevent the radial arterial spasm, which represents one of the major causes of the access site cross-over during PCI, experienced when radial artery cannulation has failed and successful access can be obtained only switching to an alternative arterial route, as the ulnar or the femoral artery. However, some unresolved problems, as fentanyl-induced hypothermia and delayed absorption of P2Y12 inhibitors required further investigations.

Effects of RMF on BKCa and Kv channels in basilar arterial smooth‑muscle cells of SHR

The current study observed the effects and investigated the mechanism of remifentanil (RMF) on the isolated cerebral basilar arteries of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. A pressure myograph system was used to observe and compare the effects of different concentrations of RMF (10⁻¹⁰-10⁻⁵ mol/l) on the diameter changes of freshly isolated cerebral basilar arteries, which have been pre-shrunk by phenylephrine (PE), an endothelium-independent vasoconstrictor. Vascular smooth-muscle cells of the cerebral basilar artery (BASMCs) were freshly obtained via enzymolysis. BKCa (large-conductance calcium-activated potassium channels) current (I_BKCa) and Kv (voltage-gated potassium channels) current (I_Kv) were recorded using a whole-cell patch-clamp technique. The changes in I_BKCa and I_Kv produced by different concentrations of RMF (10⁻¹⁰ to 10⁻⁵ mol/l) on the two types of rats with the holding potential of −40 mV were observed and compared. The cerebral basilar arteries of the SHR and WKY rats were relaxed by RMF in a concentration-dependent manner (P<0.05; n=5). At the same concentration, the diastolic effect of RMF on SHR was weaker than that observed in WKY rats (P<0.05, n=5). When the rats were pre-perfused with 10⁻³ mol/l of the BKCa channel blocker tetraethylammonium (TEA), the diastolic amplitudes of RMF in SHR and WKY rats were decreased, and the fitting curves shifted down (P<0.05; n=7 and 6, respectively). However, no statistically significant difference was observed with 10⁻³ mol/l of the Kv channel blocker 4-aminopyridine (4-AP; n=6 and 9, respectively; P>0.05). Outward currents were increased by RMF in both BASMCs of SHR and WKY rats in a voltage- and dose-dependent manner (P<0.05; n=6). At the same concentration, the effect of RMF on the outward currents in BASMCs of WKY rats was stronger than that on SHR (P<0.05; n=6). The enhancing effect of RMF can be partially blocked by either 10⁻³ mol/l TEA (P<0.05; n=6) or 10⁻³ mol/l 4-AP (P<0.05 or 0.01; n=6 and 9, respectively) however can be totally blocked by the mixture of TEA and 4-AP (P<0.05, n=7). RMF served a diastolic role in the cerebral basilar arteries of rats in a dose-dependent manner, likely by activating the BKCa and Kv channels. However, SHR demonstrated a less pronounced diastolic reaction to RMF than that observed in WKY rats.

The Effects of Vaccinium myrtillus Extract on Hamster Pial Microcirculation during Hypoperfusion-Reperfusion Injury

Introduction

The present study was aimed to assess the in vivo hamster pial microvessel alterations due to 30 min transient bilateral common carotid artery occlusion (BCCAO) and reperfusion (60 min); moreover, the neuroprotective effects of Vaccinium myrtillus extract, containing 34.7% of anthocyanins, were investigated.

Materials and Methods

Two groups of male hamsters were used: the first fed with control diet and the other with Vaccinium myrtillus supplemented diet. Hamster pial microcirculation was visualized by fluorescence microscopy through an open cranial window. Pial arterioles were classified according to Strahler’s method.

Results

In age-matched control diet-fed hamsters, BCCAO caused a decrease in diameter of all arterioles. At the end of reperfusion, the reduction of diameter in order 3 arterioles was by 8.4 ± 3.1%, 10.8 ± 2.3% and 12.1 ± 1.1% of baseline in the 2, 4 and 6 month control diet-fed hamsters, respectively. Microvascular permeability and leukocyte adhesion were markedly enhanced, while perfused capillary length (PCL) decreased. The response to acetylcholine and papaverine topical application was impaired; 2’-7’-dichlorofluoresceine-diacetate assay demonstrated a significant ROS production. At the end of BCCAO, in age-matched Vaccinium myrtillussupplemented diet-fed hamsters, the arteriolar diameter did not significantly change compared to baseline. After 60 min reperfusion, order 3 arterioles dilated by 9.3 ± 2.4%, 10.6 ± 3.1% and 11.8 ± 2.7% of baseline in the 2, 4 and 6 month Vaccinium myrtillus supplemented diet-fed hamsters, respectively. Microvascular leakage and leukocyte adhesion were significantly reduced in all groups according to the time-dependent treatment, when compared with the age-matched control diet-fed hamsters. Similarly, the reduction in PCL was progressively prevented. Finally, the response to acetylcholine and papaverine topical application was preserved and there was no significant increase in ROS production in all groups.

Conclusions

In conclusion, Vaccinium myrtillusextract protected pial microcirculation during hypoperfusion-reperfusion, preventing vasoconstriction, microvascular permeability, leukocyte adhesion, reduction in PCL and preserving the endothelium function.

The application of transcutaneous CO2 pressure monitoring in the anesthesia of obese patients undergoing laparoscopic bariatric surgery

To investigate the correlation and accuracy of transcutaneous carbon dioxide partial pressure (PTCCO2) with regard to arterial carbon dioxide partial pressure (PaCO2) in severe obese patients undergoing laparoscopic bariatric surgery. Twenty-one patients with BMI>35 kg/m(2) were enrolled in our study. Their PaCO2, end-tidal carbon dioxide partial pressure (PetCO2), as well as PTCCO2 values were measured at before pneumoperitoneum and 30 min, 60 min, 120 min after pneumoperitoneum respectively. Then the differences between each pair of values (PetCO2-PaCO2) and. (PTCCO2-PaCO2) were calculated. Bland-Altman method, correlation and regression analysis, as well as exact probability method and two way contingency table were employed for the data analysis. 21 adults (aged 19-54 yr, mean 29, SD 9 yr; weight 86-160 kg, mean 119.3, SD 22.1 kg; BMI 35.3-51.1 kg/m(2), mean 42.1,SD 5.4 kg/m(2)) were finally included in this study. One patient was eliminated due to the use of vaso-excitor material phenylephrine during anesthesia induction. Eighty-four sample sets were obtained. The average PaCO2-PTCCO2 difference was 0.9 ± 1.3 mmHg (mean ± SD). And the average PaCO2-PetCO2 difference was 10.3 ± 2.3 mmHg (mean ± SD). The linear regression equation of PaCO2-PetCO2 is PetCO2 = 11.58+0.57 × PaCO2 (r(2) = 0.64, P<0.01), whereas the one of PaCO2-PTCCO2 is PTCCO2 = 0.60 + 0.97 × PaCO2 (r(2) = 0.89). The LOA (limits of agreement) of 95% average PaCO2-PetCO2 difference is 10.3 ± 4.6 mmHg (mean ± 1.96 SD), while the LOA of 95% average PaCO2-PTCCO2 difference is 0.9 ± 2.6 mmHg (mean ± 1.96 SD). In conclusion, transcutaneous carbon dioxide monitoring provides a better estimate of PaCO2 than PetCO2 in severe obese patients undergoing laparoscopic bariatric surgery.

Moderate procedural sedation and opioid analgesia during transradial coronary interventions to prevent spasm: a prospective randomized study

OBJECTIVES

The aim of this study was to test the hypothesis that moderate procedural sedation can reduce the incidence of radial artery spasm.

BACKGROUND

Transradial access for left heart catheterization and percutaneous coronary intervention is increasingly used for emergent and elective procedures, in lieu of the femoral approach. However, increased rates of access site crossover have been reported, with radial artery spasm being a major contributor to this effect.

METHODS

Patients undergoing elective transradial percutaneous coronary intervention were prospectively randomized to receive fentanyl and midazolam during the procedure or no treatment (control subjects). The primary endpoint was angiographically confirmed radial artery spasm. Patient discomfort was quantified with a visual analogue scale.

RESULTS

Two thousand thirteen patients (age 64.5 ± 8.4 years) were randomized. Spasm occurred in 2.6% of the treatment group versus 8.3% of control subjects (p < 0.001; odds ratio [OR]: 0.29). The number needed to treat to avoid 1 case of spasm was 18 (95% confidence interval [CI]: 12.9 to 26.6). The access site crossover rate was 34% lower in the treatment group: 9.9% versus 15.0% (OR: 0.62; 95% CI: 0.48 to 0.82). Patient discomfort visual analogue scale score was 18.8 ± 12.5 in the treatment group versus 27.4 ± 17.4 in control subjects (p < 0.001). No significant differences were observed in the 30-day rate of death or repeat hospital stay for any cause: 4.6% versus 4.5% (OR: 1.02; 95% CI: 0.67 to 1.56).

CONCLUSIONS

Routine administration of relatively low doses of an opioid/benzodiazepine combination during transradial interventional procedures is associated with a substantial reduction in the rate of spasm, the need for access site crossover, and the procedure-related level of patient discomfort.

Flurbiprofen axetil provides a prophylactic benefit against mesenteric traction syndrome associated with remifentanil infusion during laparotomy

PURPOSE

Mesenteric traction syndrome (MTS) is caused by PGI(2) release during abdominal procedures and is often observed during abdominal surgery. We have demonstrated that MTS occurs more frequently in cases using remifentanil than in those that are not. The aim of this study was to assess the prophylactic benefit of flurbiprofen axetil on MTS in patients undergoing abdominal surgery using remifentanil.

METHODS

Thirty ASA physical status I and II patients were enrolled. They were scheduled to undergo abdominal surgery under general anesthesia with remifentanil and were randomly assigned to receive flurbiprofen axetil (group F) or saline (group C) preoperatively (n = 15 each). MTS was defined according to our simplified diagnostic criteria. Arterial blood pressure and heart rate were recorded, and the plasma 6-keto-PGF(1α) (a stable metabolite of PGI(2)) concentration was measured just before skin incision and at 20 and 60 min after skin incision (T(0), T(20), T(60)) to confirm the diagnosis of MTS.

RESULTS

Twelve of 15 (80%) patients developed MTS in group C, whereas only 1 of 15 (6.7%) patients in group F developed MTS. At T(20), the group C patients showed significantly lower arterial blood pressure (P < 0.05) and a faster heart rate (P < 0.01) than those in group F. The mean plasma 6-keto-PGF(1α) concentration was significantly elevated in group C at T(20) (P < 0.01), whereas the plasma 6-keto-PGF(1α) level remained low throughout the observation period in group F.

CONCLUSIONS

We found that preoperative administration of flurbiprofen axetil reduced the incidence of MTS during abdominal surgery with remifentanil analgesia.

Therapeutic hypothermia and controlled normothermia in the intensive care unit: practical considerations, side effects, and cooling methods

BACKGROUND

Hypothermia is being used with increasing frequency to prevent or mitigate various types of neurologic injury. In addition, symptomatic fever control is becoming an increasingly accepted goal of therapy in patients with neurocritical illness. However, effectively controlling fever and inducing hypothermia poses special challenges to the intensive care unit team and others involved in the care of critically ill patients.

OBJECTIVE

To discuss practical aspects and pitfalls of therapeutic temperature management in critically ill patients, and to review the currently available cooling methods.

DESIGN

Review article.

INTERVENTIONS

None.

MAIN RESULTS

Cooling can be divided into three distinct phases: induction, maintenance, and rewarming. Each has its own risks and management problems. A number of cooling devices that have reached the market in recent years enable reliable maintenance and slow and controlled rewarming. In the induction phase, rapid cooling rates can be achieved by combining cold fluid infusion (1500-3000 mL 4 degrees C saline or Ringer's lactate) with an invasive or surface cooling device. Rapid induction decreases the risks and consequences of short-term side effects, such as shivering and metabolic disorders. Cardiovascular effects include bradycardia and a rise in blood pressure. Hypothermia's effect on myocardial contractility is variable (depending on heart rate and filling pressure); in most patients myocardial contractility will increase, although mild diastolic dysfunction can develop in some patients. A risk of clinically significant arrhythmias occurs only if core temperature decreases below 30 degrees C. The most important long-term side effects of hypothermia are infections (usually of the respiratory tract or wounds) and bedsores.

CONCLUSIONS

Temperature management and hypothermia induction are gaining importance in critical care medicine. Intensive care unit physicians, critical care nurses, and others (emergency physicians, neurologists, and cardiologists) should be familiar with the physiologic effects, current indications, techniques, complications and practical issues of temperature management, and induced hypothermia. In experienced hands the technique is safe and highly effective.

Endogenous opiates and behavior: 2006

This paper is the 29th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning 30 years of research. It summarizes papers published during 2006 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurological disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).