Pain during arterial puncture

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.

Pitfalls in the diagnosis and management of acid-base disorders in humans: a laboratory medicine perspective

Diagnostic errors affect patient management, and as blood gas analysis is mainly performed without the laboratory, users must be aware of the potential pitfalls. The aim was to provide a summary of common issues users should be aware of.A narrative review was performed using online databases such as PubMed, Google Scholar and reference lists of identified papers. Language was limited to English.Errors can be pre-analytical, analytical or post-analytical. Samples should be analysed within 15 min and kept at room temperature and taken at least 15-30 min after changes to inspired oxygen and ventilator settings, for accurate oxygen measurement. Plastic syringes are more oxygen permeable if chilled. Currently, analysers run arterial, venous, capillary and intraosseous samples, but variations in reference intervals may not be appreciated or reported. Analytical issues can arise from interference secondary to drugs, such as spurious hyperchloraemia with salicylate and hyperlactataemia with ethylene glycol, or pathology, such as spurious hypoxaemia with leucocytosis and alkalosis in hypoalbuminaemia. Interpretation is complicated by result adjustment, for example, temperature (alpha-stat adjustment may overestimate partial pressure of carbon dioxide (pCO2) in hypothermia, for example), and inappropriate reference intervals, for example, in pregnancy bicarbonate, and pCO2 ranges should be lowered.Lack of appreciation for patient-specific and circumstance-specific reference intervals, including extremes of age and altitude, and transformation of measurements to standard conditions can lead to inappropriate assumptions. It is vitally important for users to optimise specimen collection, appreciate the analytical methods and understand when reference intervals are applicable to their specimen type, clinical question or patient.

The use of venous blood gas in assessing arterial acid-base and oxygenation status - an analysis of aggregated data from multiple studies evaluating the venous to arterial conversion (v-TAC) method

BACKGROUND

Several methods exist to reduce the number of arterial blood gases (ABGs). One method, Roche v-TAC, has been evaluated in different patient groups. This paper aggregates data from these studies, in different patient categories using common analysis criteria.

RESEARCH DESIGN AND METHODS

We included studies evaluating v-TAC based on paired arterial and peripheral venous blood samples. Bland-Altman analysis compared measured and calculated arterial values of pH, PCO2, and PO2. Subgroup analyses were performed for normal, chronic hypercapnia and chronic base excess, acute hyper- and hypocapnia, and acute and chronic base deficits.

RESULTS

811 samples from 12 studies were included. Bias and limits of agreement for measured and calculated values: pH 0.001 (-0.029 to 0.031), PCO2 -0.08 (-0.65 to 0.49) kPa, and PO2 0.04 (-1.71 to 1.78) kPa, with similar values for all sub-group analyses.

CONCLUSION

These data suggest that v-TAC analysis may have a role in replacing ABGs, avoiding arterial puncture. Substantial data exist in patients with chronic hypercapnia and chronic base excess, acute hyper- and hypocapnia, and in patients with relatively normal acid-base status, with similar bias and precision across groups and across study data. Limited data exist for patients with acute and chronic base deficits.

Efficacy of Local Anesthesia for Radial Artery Puncture Pain: A Systematic Review and Network Meta-Analysis

We performed a systematic review and network meta-analysis (NMA) to assist clinicians in determining the optimal patient-specific method of analgesia during radial artery puncture by comparing radial artery puncture procedural pain. We included randomized controlled trials that assessed the prophylactic efficacy of local anesthesia for radial artery puncture-associated pain. We searched the Medical Literature Analysis and Retrieval System Online in January 2023, the Cochrane Central Register of Controlled Trials in January 2023, the Excerpta Medica Database in December 2022, the World Health Organization International Clinical Trials Platform Search Portal in January 2023, and ClinicalTrials.gov in January 2023. We synthesized the pain scores (0-100 scale) using the frequentist random-effects NMA model. We evaluated the confidence in each outcome using the CINeMA tool (https://cinema.ispm.unibe.ch/). We conducted an NMA of 1,619 patients across 14 studies on pain scores during radial artery puncture-related procedures for 12 interventions. Compared with placebo, mepivacaine infiltration and lidocaine spray probably reduce pain (mean difference (MD): -47.67, 95% confidence interval (CI): -61.45 to -33.89, confidence rating (CR): moderate; MD: -27.38, 95% CI: -37.53 to -17.22, CR: moderate). Of the 32 studies included, none reported systemic adverse events, such as anaphylaxis or local anesthetic systemic toxicity, or severe local adverse events. In conclusion, mepivacaine infiltration and lidocaine spray probably reduce the pain associated with radial artery puncture more than other local anesthesia.

Gender Differences among Nurses in Managing Arterial Puncture-Related Pain: A Multicenter Cross-Sectional Study

There is evidence that healthcare can be executed differentially depending on the gender of patients, researchers, and clinicians. The aim was to analyze the possible existence of nursing gender differences in pain management produced by arterial puncture for blood gas analysis. A cross-sectional, multicenter study designed was conducted in Castilla-la Mancha (Spain). Variables of interest were collected from nurses in the public health system of a European region through a questionnaire. Data were collected for four months; the primary outcome was the use of any intervention to reduce pain and the explanatory variable was the nurse's gender. Bivariate analysis was carried out to assess associations between gender and pain-reducing interventions and a multivariate model was created with those factors that were relevant using logistic regression. A significantly higher proportion of men reported using some form of intervention (45% vs. 30%) and had more specific training (45.9% vs. 32.4%). The adjusted probability of using pain-reducing interventions by men was 71% higher than women. Thus, we found gender differences in the management of pain caused by arterial punctures performed by nurses as the main healthcare providers.

The Effect of Positive Therapeutic Communication on Pain (POPAIN) and Anxiety During Arterial Blood Gas Standardized Procedures in the Emergency Department Compared to Traditional Communication: Protocol for a Monocentric Randomized Controlled Trial

BACKGROUND

In the emergency department (ED), medical procedures, such as arterial blood gas (ABG) testing, can cause pain and high stress levels. However, ABG testing is a routine procedure assessing the severity of the patient's condition. To reduce the pain of ABG, several methods have been investigated without significant difference in pain perception. Communication, a key element of care, has shown a significant effect on pain perception. A positive communication strategy, including positive, kind, or reassuring words, can reduce pain perception, while negative words can raise this perception, causing discomfort, known as the "nocebo effect." Although some studies have compared the impact of verbal attitudes, particularly in anesthesia and mainly with staff already trained in hypnosis, to the best of our knowledge, none have investigated the effect of communication in the emergency setting, where patients may be more suggestible to the words used.

OBJECTIVE

In this study, we will investigate the effect of positive therapeutic communication on pain, anxiety, discomfort, and global satisfaction in patients requiring ABG compared to nocebo and neutral communication.

METHODS

A single-center, double-blind randomized controlled trial (RCT) with 3 parallel arms will be conducted with 249 patients requiring ABG during their ED visit. Patients will be randomly assigned to 1 of 3 groups before receiving ABG: positive communication group, negative communication (nocebo) group, or neutral communication (neutral) group. The communication and the words used by the physicians during hygiene preparation, artery location, and puncture will be imposed in each group. The study will be proposed to each patient corresponding to the inclusion criteria. The physicians will not be trained in hypnosis or in positive therapeutic communication. The procedure will be recorded with audio recorders to test its quality. Intention-to-treat analysis will be performed. The primary endpoint is the onset of pain. The secondary outcomes are patient comfort, patient anxiety, and global satisfaction of the patient with the communication strategy used.

RESULTS

On average, 2000 ABG procedures are performed each year in the EDs of hospitals. In this study, 249 patients are expected to be included. With a projected positive response rate of 80%, we intend to include 25 (10%) patients per month. The inclusion period began in April 2023 and will run until July 2024. We hope to publish the results of the study during the fall of 2024.

CONCLUSIONS

To the best of our knowledge, this study is the first RCT assessing the use of positive communication on pain and anxiety in patients undergoing the ABG procedure in the ED. A reduction in pain, discomfort, and anxiety is expected when using positive communication. If the results are positive, this could be useful to the medical community and encourage clinicians to monitor their communication during care.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05434169; https://clinicaltrials.gov/ct2/show/NCT05434169.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/42043.

Arterial line insertion

Arterial line insertion is a common ED procedure with considerable clinician variation in preferred technique and equipment. This article aims to review some of the controversies and evidence surrounding this common ED procedure.

Validation of Noninvasive Assessment of Pulmonary Gas Exchange in Patients with Chronic Obstructive Pulmonary Disease during Initial Exposure to High Altitude

Investigation of pulmonary gas exchange efficacy usually requires arterial blood gas analysis (aBGA) to determine arterial partial pressure of oxygen (mPaO2) and compute the Riley alveolar-to-arterial oxygen difference (A-aDO2); that is a demanding and invasive procedure. A noninvasive approach (AGM100), allowing the calculation of PaO2 (cPaO2) derived from pulse oximetry (SpO2), has been developed, but this has not been validated in a large cohort of chronic obstructive pulmonary disease (COPD) patients. Our aim was to conduct a validation study of the AG100 in hypoxemic moderate-to-severe COPD. Concurrent measurements of cPaO2 (AGM100) and mPaO2 (EPOC, portable aBGA device) were performed in 131 moderate-to-severe COPD patients (mean ±SD FEV1: 60 ± 10% of predicted value) and low-altitude residents, becoming hypoxemic (i.e., SpO2 < 94%) during a short stay at 3100 m (Too-Ashu, Kyrgyzstan). Agreements between cPaO2 (AGM100) and mPaO2 (EPOC) and between the O2-deficit (calculated as the difference between end-tidal pressure of O2 and cPaO2 by the AGM100) and Riley A-aDO2 were assessed. Mean bias (±SD) between cPaO2 and mPaO2 was 2.0 ± 4.6 mmHg (95% Confidence Interval (CI): 1.2 to 2.8 mmHg) with 95% limits of agreement (LoA): -7.1 to 11.1 mmHg. In multivariable analysis, larger body mass index (p = 0.046), an increase in SpO2 (p < 0.001), and an increase in PaCO2-PETCO2 difference (p < 0.001) were associated with imprecision (i.e., the discrepancy between cPaO2 and mPaO2). The positive predictive value of cPaO2 to detect severe hypoxemia (i.e., PaO2 ≤ 55 mmHg) was 0.94 (95% CI: 0.87 to 0.98) with a positive likelihood ratio of 3.77 (95% CI: 1.71 to 8.33). The mean bias between O2-deficit and A-aDO2 was 6.2 ± 5.5 mmHg (95% CI: 5.3 to 7.2 mmHg; 95%LoA: -4.5 to 17.0 mmHg). AGM100 provided an accurate estimate of PaO2 in hypoxemic patients with COPD, but the precision for individual values was modest. This device is promising for noninvasive assessment of pulmonary gas exchange efficacy in COPD patients.

Ultrasound guidance versus conventional technique for radial artery puncture in septic shock patients: A pilot study

BACKGROUND

Arterial puncture, for obtaining an analysis of blood gas, is an interventional procedure often performed in emergency departments and intensive care units. This study compares the ultrasound (US) guided method with the conventional digital palpation method in radial artery puncture (RAP) for blood gas analysis in septic shock patients.

METHODS

This is a prospective, single-centre study. Septic shock patients over 18 years of age who needed a RAP sample for blood gas analysis were included. Patients with local infection or trauma at the puncture site, arteriovenous fistula, vascular graft, coagulopathy, a positive Allen test, or did not want to participate were excluded. Patients were randomized into two groups and RAP was obtained with either the US-guided method or the conventional method. The main outcomes were success at first entry, the number of attempts before success, and the time to success.

RESULTS

The 50 eligible patients were randomized into two groups. First entry success rate for the US-guided group and the conventional group was 80% and 42%, respectively. The number of attempts before success and time to success was significantly higher in the conventional group.

CONCLUSION

The US-guided method has been found to be more successful in terms of first entry success, the number of attempts before success, and the time to success when compared to the conventional method.

Padded Dressing with Lidocaine HCL for Reducing Pain during Intravenous Cannulation in Adult Patients: A Randomized Controlled Clinical Trial

Objective. In this study, we aimed to evaluate the effect of administering lidocaine as a local anesthetic at the puncture site prior cannulation on reduction of pain during intravenous cannulation (IVC). Methods. A total of 77 patients were divided into two groups as the patients who received a local anesthetic prior IVC procedure ( $n=40$ ) and the control group ( $n=37$ ). Patients’ demographic data, including age, gender, height, weight and body mass index, IV gauge, IV site, heart rate (HR), and oxygen saturation (SpO2) were recorded and analyzed. Patients in both groups scored the pain they felt during IVC through the visual analog scale (VAS) and the verbal descriptor scale (VDS). Results. No statistically significant difference was found between the two groups in terms of the demographic features. There was no significant difference between the two groups in terms of the cannula gauges and site of IVC. The mean post-IVC HR value was statistically significantly higher compared to pre-IVC in the control group ( $p=0.032$ ), while no difference was found between the mean pre- and postprocedure HR in the lidocaine group. The mean VAS score was significantly lower in the lidocaine group compared to the control group ( $p<0.001$ ). There was a significant difference between the groups in terms of the current VDSs. The rate of the patients reporting mild pain was statistically significantly higher in the lidocaine group compared to the control subjects ( $p<0.001$ ). Conclusion. According to the results of this study, lidocaine HCL-impregnated padded dressing prior IV cannulation significantly reduced pain sensation during IVC.

Arterial Blood Gas Analysis: as safe as we think? A multicentre historical cohort study

Purpose

Methods

Results

Conclusion

Arterial punctures for arterial blood gas analysis are safe procedures with a major complication rate within 7 days of 0.14% (95% CI 0.13–0.15%). Patients on antithrombotic medication have an increased risk of developing major complications.https://bit.ly/3FaPOwk

Interventions to reduce arterial puncture-related pain: A systematic review and meta-analysis

BACKGROUND

Arterial puncture-related pain remains unaddressed across several clinical settings. Analgesic techniques are not routinely employed before arterial puncture despite the recommendation that local anesthesia be used, except in emergencies. A comprehensive review of interventions aimed at reducing arterial puncture-related pain and their potential effectiveness is lacking, and the benefit of some interventions is uncertain.

OBJECTIVE

To describe interventions aimed at reducing arterial puncture-related pain and provide an estimate of their effectiveness.

DESIGN

Systematic review and meta-analysis (PROSPERO no. CRD42020212299).

DATA SOURCE(S)

PubMed, CINAHL EBSCO, EMBASE, the Cochrane Database of Systematic Reviews, and Scopus were searched from their inception to 7 October 2020. No temporal or language limits were applied.

METHODS

Published, quantitative studies on interventions aimed at reducing arterial puncture-related pain among adults were included. Screening, quality appraisal, and data extraction were undertaken independently by two reviewers. Random effects meta-analyses were performed to assess the association between interventions aimed at reducing arterial puncture-related pain and patients' perceived pain using difference in means (MD) with 95% confidence intervals (CIs). A funnel plot and Egger test were used to assess publication bias.

RESULTS

The titles and abstracts of the 2446 identified articles were screened, and 43 and 31 studies were finally included in the systematic review and meta-analysis, respectively. Interventions to reduce arterial puncture-related pain included: topical anesthetics (n = 16), cryotherapy (n = 9), local anesthetic infiltration (n = 5), narrower needle gage (n = 5), ultrasound-guided procedure (n = 3), topical anesthetics combined with local anesthetic infiltration (n = 1), iontophoresis using anesthetics (n = 1), engineered blood gas syringe (n = 1), jet injector (n = 1), and local massage (n = 1). Topical anesthetics [MD -0.58, 95% CI -1.00, -0.15], cryotherapy [MD -1.13, 95% CI -1.72, -0.53], and local anesthetic infiltration [MD -1.13, 95% CI -1.72, -0.53] reduced arterial puncture-related pain. No benefit was found for narrower needle gage [MD -0.07, 95% CI -0.86, 0.71] or ultrasound-guided procedure [MD -1.74, 95% CI -3.51, 0.03]. No publication bias was detected.

CONCLUSIONS

Local anesthetic infiltration provided the greatest pain reduction and should be considered standard practice. Cryotherapy may be a safe, convenient alternative to local anesthetic infiltration. Topical anesthetics had limited benefit, and their lengthy time of onset makes them unsuitable for critical or emergency situations, though they may represent an option when comorbid conditions make cooling impossible. Caution must be used when interpreting these results, given the high risk of bias in the methods of included studies and the heterogeneity across the studies.

Mathematically arterialised venous blood is a stable representation of patient acid-base status at steady state following acute transient changes in ventilation

Hyper- or hypoventilation are commonly occurring stress responses to arterial puncture around the time of blood sampling and have been shown to rapidly alter arterial blood acid–base parameters. This study aimed to evaluate a physiology-based mathematical method to transform peripheral venous blood acid–base values into mathematically arterialised equivalents following acute, transient changes in ventilation. Data from thirty patients scheduled for elective surgery were analysed using the physiology-based method. These data described ventilator changes simulating ‘hyper-’ or ‘hypoventilation’ at arterial puncture and included acid–base status from simultaneously drawn blood samples from arterial and peripheral venous catheters at baseline and following ventilatory change. Venous blood was used to calculate mathematically arterialised equivalents using the physiology-based method; baseline values were analysed using Bland–Altman plots. When compared to baseline, measured arterial and calculated arterialised values at each time point within limits of pH: ± 0.03 and PCO₂: ± 0.5 kPa, were considered ‘not different from baseline’. Percentage of values considered not different from baseline were calculated at each sampling timepoint following hyper- and hypoventilation. For the physiological method, bias and limits of agreement for pH and PCO₂ were -0.001 (-0.022 to 0.020) and -0.02 (-0.37 to 0.33) kPa at baseline, respectively. 60 s following a change in ventilation, 100% of the mathematically arterialised values of pH and PCO₂ were not different from baseline, compared to less than 40% of the measured arterial values at the same timepoint. In clinical situations where transient breath-holding or hyperventilation may compromise the accuracy of arterial blood samples, arterialised venous blood is a stable representative of steady state arterial blood.

Oximetry neither to prescribe long-term oxygen therapy nor to screen for severe hypoxaemia

BACKGROUND AND OBJECTIVE

Transcutaneous pulse oximetry saturation (S pO2 ) is widely used to diagnose severe hypoxaemia and to prescribe long-term oxygen therapy (LTOT) in COPD. This practice is not based on evidence. The primary objective of this study was to determine the accuracy (false positive and false negative rates) of oximetry for prescribing LTOT or for screening for severe hypoxaemia in patients with COPD.

METHODS

In a cross-sectional study, we correlated arterial oxygen saturation (S aO2 ) and S pO2 in patients with COPD and moderate hypoxaemia (n=240) and calculated the false positive and false negative rates of S aO2 at the threshold of ≤88% to identify severe hypoxaemia (arterial oxygen tension (P aO2 ) ≤55 mmHg or P aO2 <60 mmHg) in 452 patients with COPD with moderate or severe hypoxaemia.

RESULTS

The correlation between S aO2 and S pO2 was only moderate (intra-class coefficient of correlation: 0.43; 95% confidence interval: 0.32-0.53). LTOT would be denied in 40% of truly hypoxaemic patients on the basis of a S aO2 >88% (i.e., false negative result). Conversely, LTOT would be prescribed on the basis of a S aO2 ≤88% in 2% of patients who would not qualify for LTOT (i.e., false positive result). Using a screening threshold of ≤92%, 5% of severely hypoxaemic patients would not be referred for further evaluation.

CONCLUSIONS

Several patients who qualify for LTOT would be denied treatment using a prescription threshold of saturation ≤88% or a screening threshold of ≤92%. Prescription of LTOT should be based on P aO2 measurement.

Agreement between Arterial and Capillary pH, pCO2, and Lactate in Patients in the Emergency Department

Background

Blood gas analysis (BGA) is a frequent painful procedure in emergency departments. The primary objective of the study was a quantitative analysis to assess the mean difference and 95% confidence interval of the difference between capillary and arterial BGA for pH, pCO₂, and lactate. Secondary objective was to measure the sensitivity and specificity of capillary samples to detect altered pH, hypercarbia, and lactic acidosis. Adults admitted to the ED were screened for inclusion. We studied the agreement between the two methods for pH, pCO₂, and lactate with Bland-Altman bias plot analysis and receiver operating characteristic curves.

Results

One hundred ninety-seven paired analyses were included. Mean difference for pH between arterial and capillary BGA was 0.0095, and 95% limits of agreement (LOA) were −0.048 to 0.067. For pCO₂, mean difference was −0.3 mmHg, and 95% LOA were −8.5 to 7.9 mmHg. Lactate mean difference was −0.93 mmol/L, and 95% LOA were −2.7 to 0.8 mmol/L. At a threshold of 7.34, capillary pH had 98% sensitivity and 97% specificity to detect acidemia; at 45.9 mmHg, capillary pCO₂ had 89% sensitivity and 96% specificity to detect hypercarbia. At a threshold of 3.5 mmol/L, capillary lactate had 66% sensitivity to detect lactic acidosis.

Conclusion

Capillary BGA cannot replace arterial BGA despite high concordance between the two methods for pH and pCO₂ and moderate concordance for lactate. Capillary measures had good accuracy when used as a screening tool to detect altered pH and hypercarbia but insufficient sensitivity and specificity when screening for lactic acidosis.

ARTP statement on pulmonary function testing 2020

The Association for Respiratory Technology & Physiology (ARTP) last produced a statement on the performance of lung function testing in 1994. At that time the focus was on a practical statement for people working in lung function laboratories. Since that time there have been many technological advances and alterations to best practice in the measurement and interpretation of lung function assessments. In light of these advances an update was warranted. ARTP, therefore, have provided within this document, where available, the most up-to-date and evidence-based recommendations for the most common lung function assessments performed in laboratories across the UK. These recommendations set out the requirements and considerations that need to be made in terms of environmental and patient factors that may influence both the performance and interpretation of lung function tests. They also incorporate procedures to ensure quality assured diagnostic investigations that include those associated with equipment, the healthcare professional conducting the assessments and the results achieved by the subject. Each section aims to outline the common parameters provided for each investigation, a brief principle behind the measurements (where applicable), and suggested acceptability and reproducibility criteria.

10% Lidocaine spray as a local anesthetic in blood gas sampling: A randomized, double-blind, placebo-controlled study

AIM

Radial artery blood gas sampling is a very common procedure undertaken in the emergency department to evaluate respiratory and metabolic parameters. This intervention causes both anxiety and pain for the patient. Therefore, the current study aimed to examine the analgesic efficacy of lidocaine spray compared to a placebo during radial artery blood gas sampling.

METHODS

This study was conducted in the emergency department of a tertiary hospital with a randomized, double-blind, placebo-controlled design. A total of 144 patients were randomly divided into two groups: One group (n = 72) received 10% lidocaine spray and the other (n = 72) was the placebo group. The analgesic efficacy of the 10% lidocaine spray was compared with the placebo group using the Visual Analog Scale (VAS).

RESULTS

In the evaluation of the analgesic efficacy of the 10% lidocaine spray, the VAS score was 1.5 [interquartile range (IQR): 2.0] for the lidocaine group and 5 (IQR: 2.0) for the placebo group. The role of lidocaine spray in reducing pain was statistically significant compared to the placebo (p = 0.000).

CONCLUSION

In blood gas sampling, 10% lidocaine spray has analgesic efficacy. Therefore, we recommend the use of lidocaine spray while performing arterial blood gas sampling in emergency departments.

Magnetic needle-tracking device for ultrasound guidance of radial artery puncture: A randomized study on a simulation model

INTRODUCTION

Ultrasound-guidance of radial artery catheter insertion improves the first attempt success and reduces the occurrence of hematomas. Needle-tracking devices optimize needle-ultrasound beam alignment by displaying in real-time the needle tip position. We compared the median time need by experienced physicians to achieve radial artery puncture using either a conventional ultrasonography device (CUD) or a magnetic needle-tracking ultrasound device (MUD) in a simulation training arm model.

METHODS

Fifty experienced residents and physicians performed two punctures in randomized order with the CUD and the MUD. The primary outcome was puncture duration; the secondary outcomes were puncture success, rate of accidental vein puncture, and practitioner's comfort (subjective scale 0-10).

RESULTS

The median [lower-upper quartile] puncture time was 10 [6-14] seconds when using CUD and 4 [3-7] seconds when using MUD (P < .01). In the multivariate analysis, MUD use was associated with decreased puncture duration whatever the puncture order (OR 1.13 [1.07-1.20], P < .01). The participants performed 99 (99%) successful punctures: 50 with the MUD (100%) and 49 with the CUD (98%). There was no accidental venous puncture. The practitioner's comfort level was 6.5 [6, 7] with the CUD and 8 [7-9] with the MUD (P < .01).

CONCLUSION

MUD reduced radial artery puncture time and improved physician comfort in a simulation training arm model.

Is venous blood a more reliable description of acid-base state following simulated hypo- and hyperventilation?

Background

ABGs are performed in acute conditions as the reference method for assessing the acid-base status of blood. Hyperventilation and breath-holding are common ventilatory changes that occur around the time of sampling, rapidly altering the ‘true’ status of the blood. This is particularly relevant in emergency medicine patients without permanent arterial catheters, where the pain and anxiety of arterial punctures can cause ventilatory changes. This study aimed to determine whether peripheral venous values could be a more reliable measure of blood gases following acute changes in ventilation.

Methods

To allow for characterisation of ventilatory changes typical of acutely ill patients, but without the confounding influence of perfusion or metabolic disturbances, 30 patients scheduled for elective surgery were studied in a prospective observational study. Following anaesthesia, and before the start of the surgery, ventilator settings were altered to achieve a + 100% or − 60% change in alveolar ventilation (‘hyper-’ or ‘hypoventilation’), changes consistent with the anticipation of a painful arterial puncture commonly encountered in the emergency room. Blood samples were drawn simultaneously from indwelling arterial and peripheral venous catheters at baseline, and at 15, 30, 45, 60, 90 and 120 s following the ventilatory change. Comparisons between the timed arterial (or venous) samples were done using repeated-measures ANOVA, with post-hoc analysis using Bonferroni’s correction.

Results

Arterial blood pH and PCO₂ changed rapidly within the first 15–30s after both hyper- and hypoventilation, plateauing at around 60s (∆pH = ±0.036 and ∆PCO₂ = ±0.64 kPa (4.7 mmHg), respectively), with peripheral venous values remaining relatively constant until 60s, and changing minimally thereafter. Mean arterial changes were significantly different at 30s (P < 0.001) when compared to baseline, in response to both hyper- and hypoventilation.

Conclusion

This study has shown that substantial differences in arterial and peripheral venous acid-base status can be due to acute changes in ventilation, commonly seen in the ER over the 30s necessary to sample arterial blood. If changes are transient, peripheral venous blood may provide a more reliable description of acid-base status.

Assessment of the SpO2/FiO2 ratio as a tool for hypoxemia screening in the emergency department

Objective

We assessed the performance of the ratio of peripheral arterial oxygen saturation to the inspired fraction of oxygen (SpO₂/FiO₂) to predict the ratio of partial pressure arterial oxygen to the fraction of inspired oxygen (PaO₂/FiO₂) among patients admitted to our emergency department (ED) during the SARS-CoV-2 outbreak.

Methods

We retrospectively studied patients admitted to an academic-level ED in France who were undergoing a joint measurement of SpO₂ and arterial blood gas. We compared SpO₂ with SaO₂ and evaluated performance of the SpO₂/FiO₂ ratio for the prediction of 300 and 400 mmHg PaO₂/FiO₂ cut-off values in COVID-19 positive and negative subgroups using receiver-operating characteristic (ROC) curves.

Results

During the study period from February to April 2020, a total of 430 arterial samples were analyzed and collected from 395 patients. The area under the ROC curves of the SpO₂/FiO₂ ratio was 0.918 (CI 95% 0.885–0.950) and 0.901 (CI 95% 0.872–0.930) for PaO₂/FiO₂ thresholds of 300 and 400 mmHg, respectively. The positive predictive value (PPV) of an SpO₂/FiO₂ threshold of 350 for PaO₂/FiO₂ inferior to 300 mmHg was 0.88 (CI95% 0.84–0.91), whereas the negative predictive value (NPV) of the SpO₂/FiO₂ threshold of 470 for PaO₂/FiO₂ inferior to 400 mmHg was 0.89 (CI95% 0.75–0.96). No significant differences were found between the subgroups.

Conclusions

The SpO₂/FiO₂ ratio may be a reliable tool for hypoxemia screening among patients admitted to the ED, particularly during the SARS-CoV-2 outbreak.

Evaluation of Mathematical Arterialization of Venous Blood in Intensive Care and Pulmonary Ward Patients

BACKGROUND

Arterial blood gases are important when assessing acute or critically ill patients. Capillary blood and mathematical arterialization of venous blood have been proposed as alternative methods, eliminating pain and complications of arterial puncture.

OBJECTIVES

This study compares the arterial samples, arterialized venous samples, and capillary samples in ICU and pulmonary ward patients.

METHOD

Ninety-one adult patients with respiratory failure were included in the analysis. Arterial, peripheral venous, and mathematically arterialized venous samples were compared in all patients using Bland-Altman analysis, with capillary samples included in 36 patients.

RESULTS

Overall for pH and PCO2, arterialized venous values, and in the subset of 36 patients, capillary values, compared well to arterial values and were within the pre-defined clinically acceptable differences (pH ± 0.05 and PCO2 ± 0.88 kPa). For PO2, arterialized or capillary values describe arterial with similar precision (PO2 arterialized -0.03, LoA -1.48 to 1.42 kPa and PO2 capillary 0.82, LoA -1.36 to 3 kPa), with capillary values underestimating arterial.

CONCLUSIONS

Mathematical arterialization functions well in a range of patients in an ICU and ward outside the country of development of the method. Furthermore, accuracy and precision are similar to capillary blood samples. When considering a replacement for arterial sampling in ward patients, using capillary sampling or mathematical arterialization should depend on logistic ease of implementation and use rather than improved measurements of using either technique.

Using arterial blood as a substitute for venous blood in routine biochemistry parameter examinations in rabbits

Background

It has been widely accepted that there is a significant difference in peripheral blood oxygen between arteries and veins. Therefore, arterial blood has been collected for blood gas analysis, and venous blood, because it is convenient to collect, has been used for most laboratory examinations. However, venous blood is always difficult to collect in rabbits; in contrast, arterial blood is easier to obtain, and research on whether arterial blood can be used instead of venous blood for routine biochemical parameter examination is rare. Therefore, the present study was designed to explore whether arterial blood can be used as a substitute for venous blood for routine biochemistry parameter examination in rabbits.

Results

Three venous blood samples with gross hemolysis were excluded. Venous and arterial blood samples were obtained from forty-two rabbits. Arterial blood samples correlate well with venous blood in alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine transaminase (ALT), gamma-glutamyl transpeptidase (GGT), total protein (TP), globulin (GLB), serum total cholesterol (TC), serum triglyceride (TG), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), urea (Ur) and creatinine (Cr) levels by Deming regression analysis with slopes ranging from 0.893 to 1.176 and intercepts ranging from − 4.886 to 5.835. Bland-Altman analysis showed that the two sample parameters had 93%-98% of the points within the 95% consistency limits. There were significant differences between venous blood and arterial blood in ALP, TP, TC, TG, HDL, LDL and Cr, while AST, ALT, GGT, GLB and Ur showed no significant differences.

Conclusions

Arterial blood can be a substitute for venous blood in routine biochemistry parameter examinations in rabbits, especially in situations where venous blood is difficult to collect.

Reducing pain by using venous blood gas instead of arterial blood gas (VEINART): a multicentre randomised controlled trial

Introduction

Venous sampling for blood gas analysis has been suggested as an alternative to arterial sampling in order to reduce pain. The main objective was to compare pain induced by venous and arterial sampling and to assess whether the type of sampling would affect clinical management or not.

Methods

We performed an open-label randomised multicentre prospective study in four French EDs during a 4-week period. Non-hypoxaemic adults, whose medical management required blood gas analysis, were randomly allocated using a computer-generated randomisation list stratified by centres with an allocation ratio of 1:1 using random blocks to one of the two arms: venous or arterial sampling. The primary outcome was the maximal pain during sampling, using the visual analogue scale. Secondary outcomes pertained to ease of sampling as rated by the nurse drawing the blood, and physician satisfaction regarding usefulness of biochemical data.

Results

113 patients were included: 55 in the arterial and 58 in the venous sampling group. The mean maximal pain was 40.5 mm±24.9 mm and 22.6 mm±20.2 mm in the arterial group and the venous group, respectively, accounting for a mean difference of 17.9 mm (95% CI 9.6 to 26.3) (p<0.0001). Ease of blood sampling was greater in the venous group as compared with the arterial group (p=0.02). The usefulness of the results, evaluated by the prescriber, did not significantly differ (p=0.25).

Conclusions

Venous blood gas is less painful for patients than ABG in non-hypoxaemic patients. Venous blood gas should replace ABG in this setting.

Trial registration number

NCT03784664.

Relation Between Central Venous, Peripheral Venous and Arterial Lactate Levels in Patients With Sepsis in the Emergency Department

Background

Sepsis and multi-organ failure remain a major clinical problem with high morbidity and mortality worldwide. Lactate measurement remains part of the initial assessment and management of patients with sepsis. Although arterial blood is most commonly used for lactate measurement, there is increasing use of peripheral venous lactate for initial assessment and for monitoring of response to treatment in patients with sepsis. The aim of this study was to evaluate the relation between lactate levels measured from central line, peripheral vein and arterial line in patients treated for sepsis in the emergency department (ED).

Methods

This prospective study enrolled 31 patients with diagnosis of sepsis who were evaluated and treated in the ED of a university hospital. During initial resuscitation, blood samples from the artery, peripheral vein and central vein (when available) were collected and lactate concentrations were measured. Correlation between lactate values from the three different locations was assessed using Pearson correlation. Bland-Altman plots were used to evaluate agreement between lactate measurements in different sampling locations. All patients were eventually admitted to the Internal Medicine Department ward or to the intensive care unit (ICU) for further treatment.

Results

Our data showed strong, highly significant correlation between arterial and peripheral venous lactate levels (r = 0.880, P < 0.0001), between arterial and central venous blood lactate (r = 0.898, P < 0.0001) and between central and peripheral venous blood lactate (r = 0.941, P < 0.0001).

Conclusions

In this study we observed strong correlation between arterial, central vein and peripheral vein lactate concentrations in 31 patients assessed and treated for sepsis. We suggest that lactate measurement in peripheral venous blood could be used for screening and for monitoring response to therapy in sepsis patients. However, because this is a small study in only 31 patients and published data are limited, larger studies are needed in order to confirm the validity of our findings.

Ultrasound guidance in difficult radial artery puncture for blood gas analysis: A prospective, randomized controlled trial

Background

Ultrasound (US) guidance has yet to prove its applicability in radial arterial blood gas analysis (ABGA) punctures. The main objective of our study was to compare the number of first-attempt successes (NFAS) for radial arterial puncture in difficult patients with or without US guidance. The Secondary aims were to compare the number of punctures (NOP), puncture time, and patient pain.

Methods

In this single-center, randomized controlled trial, patients who required a radial ABGA and in whom the arterial puncture was assessed as difficult (because of non-palpable radial arteries or two previous puncture failures by a nurse) were assigned to the US group or no-US (NUS) group (procedure performed by a trained physician).

Results

Thirty-six patients were included in the US group and 37 in the NUS groups. The NFAS was 7 (19%) in the NUS group and 19 (53%) in the US group. The relative risk of success in the US group was 2.79 (95% CI,1.34 to 5.82), p = 0.01. In the NUS and US groups, respectively, the median NOP was 3 [2; 6] vs. 1 [1; 2], estimated difference −2.0 (95%CI, −3.4 to −0.6), p < 0.01; the respective puncture time was 3.1 [1.6; 5.4] vs. 1.4 [0.6; 3.1] min, estimated difference −1.45 (95%CI, −2.57 to −0.39), p = 0.01; the respective median patient pain was 6 [4; 8] vs. 2 [1; 4], estimated difference −4.0 (95%CI, −5.8 to −2.3); p < 0.01.

Conclusion

US guidance by a trained physician significantly improves the rate of success in difficult radial ABGA patients.

Lactate - Arterial and Venous Agreement in Sepsis: a prospective observational study

BACKGROUND

Sepsis is a common condition in the emergency department (ED). Lactate measurement is an important part of management: arterial lactate (A-LACT) measurement is the gold standard. There is increasing use of peripheral venous lactate (PV-LACT); however, there is little research supporting the interchangeability of the two measures.If PV-LACT has good agreement with A-LACT, it would significantly reduce patient discomfort and the risks of arterial sampling for a large group of acutely unwell patients, while allowing faster and wider screening, with potential reduced costs to the healthcare system.

OBJECTIVE

The aim of this study is to determine the agreement between PV-LACT and A-LACT in septic patients attending the ED.

METHODS

We carried out a prospective observational cohort study of 304 consented patients presenting with sepsis to a single UK NHS ED (110 000 adult attendances annually) taking paired PV-LACT and A-LACT. Bland-Altman analysis was carried out to determine agreement. Receiver operating characteristic curves and 2×2 tables were constructed to explore the predictive value of PV-LACT for A-LACT.

RESULTS

The mean difference (PV-LACT-A-LACT) is 0.4 mmol/l [95% confidence interval (CI): 0.37-0.45], with 95% limits of agreement from -0.4 (95% CI: -0.45 to -0.32) to 1.2 (95% CI: 1.14-1.27). A PV-LACT of at least 2 mmol/l predicts an A-LACT of at least 2 with 100% sensitivity (95% CI: 89-100%) and 83% specificity (95% CI: 77-87%).

CONCLUSION

This study is the largest comparing the two measurements, and shows good clinical agreement. We recommend using PV-LACT in the routine screening of septic patients. A PV-LACT less than 2 mmol/l is predictive of an A-LACT less than 2 mmol/l.

Influence du dosage systématique par biologie délocalisée du lactate sur le temps de passage des patients admis en salle d’accueil des urgences vitales

Objectif : L’objectif de notre étude était d’évaluer l’impact d’un dosage systématique par biologie délocalisée du lactate (DDL) sur le temps de passage en salle d’accueil des urgences vitales (SAUV).

Méthode : Il s’agit d’une étude prospective bicentrique de type avant/après réalisée dans deux services d’urgences universitaires. Deux phases ont été comparées. Lors de la première phase (septembre à décembre 2014), tous les patients d’âge supérieur ou égal à 18 ans orientés dès l’arrivée par l’infirmière organisatrice de l’accueil (IOA) en SAUV ont été inclus et ont bénéficié d’un DDL systématique. Pendant la seconde (mars à avril 2015) phase, pour les patients d’âge supérieur ou égal à 18 ans orientés dès l’arrivée par l’IOA en SAUV, le dosage du lactate a été laissé à l’appréciation du senior responsable et réalisé au laboratoire central.

Résultats : Les données sont exprimées en moyenne ± ET médiane [interquartile]. Huit cent trente-trois patients ont été inclus dont 397 dans la phase 1 et 436 dans la phase 2 (âge moyen de 63 ± 23 vs 59 ± 24 ans, p = 0,03), dont 16%ont été transférés en réanimation. Dans la phase 1 (avec DDL), la valeur moyenne du lactate (n = 397) était de 2,0 ± 1,9 mmol/l et dans la phase 2 (n = 70/436) de 2,2 ± 1,9 mmol/l (p = 0,55). La durée médiane de passage en SAUV n’était pas significativement diminuée avec DDL (165 [95–265] vs 170 [100–260] minutes, p = 0,76).

Conclusion : Notre étude n’a pas pu démontrer que l’introduction d’un DDL systématique réduit le temps de passage des patients admis en SAUV.

Improved Success Rate of Arterial Puncture for Blood Gas Analysis Through Standardization

Background

Arterial puncture for blood gas analysis is a common procedure in hospitals. The aim of the study is to determine if standardizing technique elements of the arterial puncture process could improve the success rate of technicians through the full scope of an academic medical center.

Methods

The study is conducted by the Blood Gas Laboratory at University of Utah Health's main campus. During the baseline period, technicians tallied whether arterial puncture attempts were successful or unsuccessful from December 2014 through February 2015. A small team reviewed the steps of performing arterial puncture and selected segments of the process for standardization. Starting in March 2015, staff were trained individually in the standard processes. All staff continued to tally outcomes of puncture attempts through March 2017.

Results

During the baseline period, the puncture success rate was 83.6%. From April 2015 through March 2017 the success rate was 89.2%.

Conclusion

Standardizing arterial puncture technique for blood gas analysis leads to fewer punctures.

How should we monitor patients with acute respiratory failure treated with noninvasive ventilation?

Noninvasive ventilation (NIV) is currently one of the most commonly used support methods in hypoxaemic and hypercapnic acute respiratory failure (ARF). With advancing technology and increasing experience, not only are indications for NIV getting broader, but more severe patients are treated with NIV. Depending on disease type and clinical status, NIV can be applied both in the general ward and in high-dependency/intensive care unit settings with different environmental opportunities. However, it is important to remember that patients with ARF are always very fragile with possible high mortality risk. The delay in recognition of unresponsiveness to NIV, progression of respiratory failure or new-onset complications may result in devastating and fatal outcomes. Therefore, it is crucial to understand that timely action taken according to monitoring variables is one of the key elements for NIV success. The purpose of this review is to outline basic and advanced monitoring techniques for NIV during an ARF episode.

Local Anaesthesia for Venous Cannulation and Arterial Blood Gas Sampling: Are Doctors Using It?

The pain of venous cannulation and arterial puncture can be greatly lessened by local anaesthesia. We sought information about the use of local anaesthesia for these procedures by doctors working in medicine, surgery and anaesthetics. A questionnaire was hand-delivered to 178 doctors in eight hospitals, all of whom responded.

For insertion of large-bore cannulae, local anaesthesia was used by all the anaesthetists but less than half the medical and surgical doctors. For arterial blood sampling it was used by 60% of anaesthetists and 2% of ward doctors.

Previous recommendations to use local anaesthesia seem to have been ignored, and in many instances these procedures are more painful than necessary.

Vapocoolant Spray Versus Lidocaine Infiltration for Radial Artery Cannulation: A Prospective, Randomized, Controlled Clinical Trial

OBJECTIVES

Local infiltration with lidocaine is a frequently used measure to prevent pain during arterial cannulation. Its administration is associated with pain. Vapocoolants like ethyl chloride or alkanes also affect rapid-onset anesthesia. However, their administration causes less discomfort compared with administration of lidocaine. The effectiveness of vapocoolants in mitigating discomfort associated with arterial cannulation never has been studied. The authors therefore compared vapocoolant with lidocaine for reducing discomfort caused by arterial cannulation.

DESIGN

Prospective, randomized, controlled study.

SETTING

University hospital, single center.

PARTICIPANTS

One hundred sixty adult patients requiring arterial cannulation before induction of general anesthesia for cardiac surgery or carotid endarterectomy.

INTERVENTIONS

Patients received either lidocaine infiltration or vapocoolant spray prior to arterial cannulation. Overall discomfort resulting from the whole procedure (applying local/topical anesthesia followed by arterial puncture) was rated on a 0 to 10 numerical rating scale. Puncture failure rate and time required for the intervention also were recorded.

MEASUREMENTS AND MAIN RESULTS

One hundred forty-three patients were included in the per-protocol analysis. Mean pain scores in the vapocoolant group were 3.4 (±1.58) compared with 4.5 (±2.29) in the lidocaine group (difference 1.1±0.33; p = 0.032; Mann-Whitney U-test). The higher puncture failure rate in the lidocaine group (n = 11 v 4) was not significant (p = 0.06; Fisher's exact test). The time required for the intervention was longer in the lidocaine group (138±44 s v 128±44 s; p = 0.019; Mann-Whitney U-test).

CONCLUSIONS

Vapocoolant spray is an alternative to lidocaine infiltration to mitigate discomfort associated with arterial cannulation.

Can transcutaneous carbon dioxide pressure be a surrogate of blood gas samples for spontaneously breathing emergency patients? The ERNESTO experience

BACKGROUND

It is known that the arterial carbon dioxide pressure (PaCO2) is useful for emergency physicians to assess the severity of dyspnoeic spontaneously breathing patients. Transcutaneous carbon dioxide pressure (PtcCO2) measurements could be a non-invasive alternative to PaCO2 measurements obtained by blood gas samples, as suggested in previous studies. This study evaluates the reliability of a new device in the emergency department (ED).

METHODS

We prospectively included patients presenting to the ED with respiratory distress who were breathing spontaneously or under non-invasive ventilation. We simultaneously performed arterial blood gas measurements and measurement of PtcCO2 using a sensor placed either on the forearm or the side of the chest and connected to the TCM4 CombiM device. The agreement between PaCO2 and PtcCO2 was assessed using the Bland-Altman method.

RESULTS

Sixty-seven spontaneously breathing patients were prospectively included (mean age 70 years, 52% men) and 64 first measurements of PtcCO2 (out of 67) were analysed out of the 97 performed. Nineteen patients (28%) had pneumonia, 19 (28%) had acute heart failure and 19 (28%) had an exacerbation of chronic obstructive pulmonary disease. Mean PaCO2 was 49 mm Hg (range 22-103). The mean difference between PaCO2 and PtcCO2 was 9 mm Hg (range -47 to +54) with 95% limits of agreement of -21.8 mm Hg and 39.7 mm Hg. Only 36.3% of the measurement differences were within 5 mm Hg.

CONCLUSIONS

Our results show that PtcCO2 measured by the TCM4 device could not replace PaCO2 obtained by arterial blood gas analysis.

Relating oxygen partial pressure, saturation and content: the haemoglobin-oxygen dissociation curve

Key Points

Educational Aims

To understand how oxygen is delivered to the tissues.

To understand the relationships between oxygen saturation, partial pressure, content and tissue delivery.

The clinical relevance of the haemoglobin–oxygen dissociation curve will be reviewed and we will show how a mathematical model of the curve, derived in the 1960s from limited laboratory data, accurately describes the relationship between oxygen saturation and partial pressure in a large number of routinely obtained clinical samples.

To understand the role of pulse oximetry in clinical practice.

To understand the differences between arterial, capillary and venous blood gas samples and the role of their measurement in clinical practice.

The delivery of oxygen by arterial blood to the tissues of the body has a number of critical determinants including blood oxygen concentration (content), saturation (S_O2) and partial pressure, haemoglobin concentration and cardiac output, including its distribution. The haemoglobin–oxygen dissociation curve, a graphical representation of the relationship between oxygen satur­ation and oxygen partial pressure helps us to understand some of the principles underpinning this process. Historically this curve was derived from very limited data based on blood samples from small numbers of healthy subjects which were manipulated in vitro and ultimately determined by equations such as those described by Severinghaus in 1979. In a study of 3524 clinical specimens, we found that this equation estimated the S_O2 in blood from patients with normal pH and S_O2 >70% with remarkable accuracy and, to our knowledge, this is the first large-scale validation of this equation using clinical samples. Oxygen saturation by pulse oximetry (S_pO2) is nowadays the standard clinical method for assessing arterial oxygen saturation, providing a convenient, pain-free means of continuously assessing oxygenation, provided the interpreting clinician is aware of important limitations. The use of pulse oximetry reduces the need for arterial blood gas analysis (S_aO2) as many patients who are not at risk of hypercapnic respiratory failure or metabolic acidosis and have acceptable S_pO2 do not necessarily require blood gas analysis. While arterial sampling remains the gold-standard method of assessing ventilation and oxygenation, in those patients in whom blood gas analysis is indicated, arterialised capillary samples also have a valuable role in patient care. The clinical role of venous blood gases however remains less well defined.

Understand the role of oximetry in clinical practice and how oxygen delivery, saturation and partial pressure relatehttp://ow.ly/R05hK

Radial artery blood gas sampling: a randomized controlled trial of lidocaine local anesthesia

BACKGROUND

Radial artery puncture is a common procedure and yet the role of local anesthesia for reducing the pain of this procedure continues to be debated. Clinical practice is variable and there is potential for substantial financial savings. This is the first randomized trial to investigate the effectiveness of subcutaneously injected lidocaine anesthesia on the perceived pain of radial artery puncture and the financial impact.

METHODS

Between December 2012 and April 2013, 43 patients in the Emergency Department were randomized into the intervention group to receive lidocaine 1% 1 mL subcutaneously or the control group (to receive no local anesthesia) prior to radial artery puncture for blood gas sampling. Pain was rated on a 10 cm visual analogue scale and procedural variables collected for between group analyses.

RESULTS

Overall, 41 participants were included. Subcutaneously injected lidocaine anesthesia did not reduce the median pain of radial artery puncture (control 1.8 vs. intervention 1.6 cm, P = 0.938). Those patients who had other systemically acting analgesia appeared to report reduced pain for radial artery puncture (0.60 vs. 2.30 cm, P = 0.105) as did those where a smaller 25-gauge needle was used compared to the standard 22-gauge (1.40 vs. 4.35 cm, P = 0.150), although these were not statistically significant. Anxious patients and those requesting local anesthesia experienced relatively higher levels of pain.

CONCLUSION

Local anesthesia did not reduce the perceived pain of radial artery puncture.

The Use of Ice Pack for Pain Associated with Arterial Punctures

BACKGROUND

Arterial punctures for monitoring respiratory problems are one of the most painful procedures in hospitalized patients. The knowledge regarding non-pharmacologic methods of pain management, including cold application is limited.

OBJECTIVE

This aim of this study was to determine if the application of ice pack before the procedure would decrease the pain perception of patients during the arterial puncture.

MATERIALS AND METHODS

This experimental study was undertaken among patients admitted to emergency ward in a public educational center affiliated to Ilam University of Medical Sciences, Ilam/Iran. Sixty-one eligible subjects were randomly assigned to two groups. The treatment group (n=31) received ice pack before arterial puncture, whereas the control group (n=30) received no intervention for pain management. Pain immediately and 5 minute after the arterial puncture were scored on a visual analog scale (VAS) from 0 to 10.

RESULTS

The mean of pain score immediately after the arterial puncture were 3.12 (1.68) and 4.6 (1.56) for treatment and control group, respectively (p<0. 001). The mean pain score 5 minute after the punctures were 1.9 (1.51) for treatment group and 2.53 (1.85) for control group. This difference was not statistically significant. The mean of heart rate during the procedure were 75.45 (9.76) beats/min for the treatment subjects and 75.46 (9.36) beats/min for the control group (p>0.05). Patients with previous arterial puncture reported higher pain intensity.

CONCLUSION

Cold pack is a simple, non-invasive and inexpensive technique for pain management before the arterial puncture. However, there is a need for further research regarding this topic.

A Randomized Controlled Trial on the Effect of Needle Gauge on the Pain and Anxiety Experienced during Radial Arterial Puncture

Background

Arterial punctures for assessment of arterial blood-gases can be a painful procedure. Lidocaine can be used to reduce pain prior to needle insertion but it is not a widely accepted practice. The purpose of this study was to determine whether a large size needle induces more pain compared to a smaller size needle for radial arterial puncture and to assess the anxiety associated with radial arterial punctures.

Methods

We conducted a prospective, double-blind, randomized, controlled, monocentric study including all outpatients who had a planned assessment of arterial blood gas analysis. Patients were randomized to have the arterial puncture performed with a 23 or a 25 G needle. The main judgement criteria was pain during arterial puncture. Visual analogue scale for pain (VAS-P) and visual analogue scale for anxiety (VAS-A) were used to assess pain and anxiety during radial arterial puncture.

Results

Two hundred consecutive patients were randomized. The 25 G needle was as painful as the 23 G needle (6.63 mm [0–19 mm] vs. 5.21 mm [0–18.49 mm], respectively, p = 0.527). Time for arterial puncture was longer with the 25 G needle than with the 23 G needle (42 s [35–55 s] vs. 33 s [24.5–35 s], respectively, p = 0.002). There was a correlation between the level of anxiety prior to the arterial puncture and the pain experienced by the patients (p: 0.369, p<0.0001). There was a correlation between the pain experienced by patients and the anxiety experienced in anticipation of another arterial puncture (p: 0.5124, p<0.0001).

Conclusions

The use of 23 G needle allows quicker arterial sampling and is not associated with increased pain and symptoms. Anxiety was correlated with the pain experienced by patients during arterial punctures.

Trial Registration

Clinicaltrials.gov: NCT02320916

Arterial puncture using insulin needle is less painful than with standard needle: a randomized crossover study

OBJECTIVES

Arterial punctures are important procedures performed by emergency physicians in the assessment of ill patients. However, arterial punctures are painful and can create anxiety and needle phobia in patients. The pain score of radial arterial punctures were compared between the insulin needle and the standard 23-gauge hypodermic needle.

METHODS

In a randomized controlled crossover design, healthy volunteers were recruited to undergo bilateral radial arterial punctures. They were assigned to receive either the insulin or the standard needle as the first puncture, using blocked randomization. The primary outcome was the pain score measured on a 100-mm visual analogue scale (VAS) for pain, and secondary outcomes were rate of hemolysis, mean potassium values, and procedural complications immediately and 24 hours postprocedure.

RESULTS

Fifty healthy volunteers were included in the study. The mean (±standard deviation) VAS score in punctures with the insulin needle was lower than the standard needle (23 ± 22 mm vs. 39 ± 24 mm; mean difference = -15 mm; 95% confidence interval = -22 mm to -7 mm; p < 0.001). The rates of hemolysis and mean potassium value were greater in samples obtained using the insulin needle compared to the standard needle (31.3% vs. 11.6%, p = 0.035; and 4.6 ±0.7 mmol/L vs. 4.2 ±0.5 mmol/L, p = 0.002). Procedural complications were lower in punctures with the insulin needle both immediately postprocedure (0% vs. 24%; p < 0.001) and at 24 hours postprocedure (5.4% vs. 34.2%; p = 0.007).

CONCLUSIONS

Arterial punctures using insulin needles cause less pain and fewer procedural complications compared to standard needles. However, due to the higher rate of hemolysis, its use should be limited to conditions that do not require a concurrent potassium value in the same blood sample.

Von Willebrand factor antigen for detection of hepatopulmonary syndrome in patients with cirrhosis

BACKGROUND & AIMS

Hepatopulmonary syndrome (HPS) occurs in 20-30% of patients with liver cirrhosis and is associated with a >2 fold increased mortality. Endothelial dysfunction seems to play a central role in its pathogenesis. von Willebrand factor antigen (vWF-Ag), an established marker of endothelial dysfunction, is significantly elevated in patients with liver cirrhosis, portal hypertension, and in experimental HPS. Aim of the present study was to evaluate the impact of vWF-Ag as a screening marker for presence of HPS in patients with stable cirrhosis.

METHODS

145 patients with stable liver cirrhosis were screened for presence of HPS in this prospective cohort type cross sectional diagnostic study. vWF-Ag and SaO2 levels were assessed at time of screening for HPS. Criteria of HPS were fulfilled in 31 (21%) patients.

RESULTS

vWF-Ag levels were significantly higher in patients with HPS compared to patients without HPS (p<0.001). Furthermore, vWF-Ag correlated significantly with gas exchange in HPS positive patients (p<0.05). vWF-Ag is an independent predictor of HPS after correction for sex, age, model for endstage-liver disease (MELD), and hepatic venous pressure gradient (HVPG) (OR per 1% increase of vWF-Ag: 1.02, 95% CI: 1.00-1.04, p<0.05). The best cut-off was 328% at a sensitivity of 100% and specificity of 53.5%; positive predictive value: 36.9%; negative predictive value: 100%.

CONCLUSIONS

HPS is associated with elevated vWF-Ag levels. vWF-Ag may be a useful screening tool for early detection of HPS. Further studies investigating vWF-Ag in HPS will be needed to confirm our findings.

ABG needle study: a randomised control study comparing 23G versus 25G needle success and pain scores

OBJECTIVE

To determine whether a narrower gauge needle used in ABG sampling is associated with lower pain scores and complication rates without increasing the level of difficulty of the procedure.

METHODS

We performed a prospective single-blinded randomised control study of patients from a tertiary-level emergency department in Sydney who required an ABG analysis over the period of June 2010-July 2012. Patients were randomised to either a 23G or 25G needle and the primary outcome that included pain experienced by these patient were recorded as pain scores on a 10 cm hatched visual analogue scale. The difficulty scores and complications were also noted from the operator.

RESULTS

Data for 119 consenting eligible patients were included in the analysis. 63 patients were allocated to the 23G needle group and 56 to the 25G needle group. The mean pain score was 3.5 (SD=2.7) for the 23G group and 3.4 (SD=2.7) for the 25G group with a mean difference between the pain scores of 0.1 (95% CI -0.9 to 1.1, p=0.83). The 23G and 25G mean difficulty score was 3.4 (SD=2.6) and 4.3 (SD=2.4), respectively, with a mean difference of 0.9 (95% CI -0.03 to 1.7, p=0.06). 21.6% of patient in the 23G needle group experienced some complication with regard to the sampling in the form of haematoma, tenderness or paraesthesia in comparison to 5.4% of patients in the 25G needle group (p=0.03).

CONCLUSIONS

There was no significant difference in pain scores experienced by patients undertaking ABG sampling with either a 23G or 25G needle.

TRIAL REGISTRATION NUMBER

ACTRN12609000957291.

The comparison of heparinized insulin syringes and safety-engineered blood gas syringes used in arterial blood gas sampling in the ED setting (randomized controlled study)

INTRODUCTION

The arterial blood gas measurement process is a painful and invasive procedure, often uncomfortable for both the patient and the physician. Because the patient-related factors that determine the difficulty of the process cannot be controlled, the physician-related factors and blood gas measurement techniques are a modifiable area of improvement that ought to be considered. Many hospitals use insulin syringes or syringes washed with heparin for the purpose of blood gas measurement because they do not have blood gas-specific syringes. In this prospective cross-sectional study, we aimed to compare safety-engineered blood gas syringes and conventional heparinized syringes used during the arterial blood gas extraction process in terms of ease of operation, the physician-patient satisfaction, laboratory appropriateness, and complications.

METHODS

Our study included patients whose arterial blood gas needed to be measured in the emergency department and who agreed to participate in the study. Patients were randomly divided into 2 groups. The arterial blood gas of the patients from the first group was measured by using conventional heparinized syringes, whereas safety-engineered blood gas syringes were used to measure the arterial blood gas of the patients from the second group. The groups were compared in terms of demographic data, the number of attempts, the physician and patient satisfaction, early and late-term complications, and laboratory appropriateness of the taken sample.

RESULTS

A total of 550 patients were included in our study in a 2-month study period. There were no significant differences between patients in terms of sex, age, weight, height, body mass index, and wrist circumference. In addition, the number of attempts (P=.489), patients' pain level during the procedure (P=.145), and the degree of difficulty of the procedure according to the patient (P=.109) and physician (P=.554) were not significantly different between the groups. After arterial blood gas extraction procedure, 115 patients (20.9%) developed complications. In the conventional heparinized syringe group, the complication rate (n=69; 25.1%) was significantly higher compared with the group that used safety-engineered blood gas syringes (n=46; 16%; P=.0211). Localized pain, which is one of the most common early complications, was more frequent in the conventional heparinized syringe group (19.3%). Complications in women (P=.003) and local pain (P=.01) developed lesser in the second group that used safety-engineered blood gas syringes, and the patient-physician satisfaction was higher in that group, as well. In the evaluation 48 hours after the procedure, the ratios of infection and local hematoma were higher in the conventional heparinized syringe group (P=.0213 and P < .0001).

CONCLUSION

In this study, we did not find any significant differences between the conventional heparinized syringes and safety-engineered blood gas syringes in terms of ease of operation, physician and patient satisfaction, and appropriateness of the taken sample. However, patients whose arterial blood gas was extracted by using safety-engineered blood gas syringes felt less pain and experienced fewer infections and hematomas at their puncture site.

How sharp is a "sharp scratch"? A mixed methods study of verbal warnings issued before venipuncture

OBJECTIVES

Health care providers frequently issue a verbal warning before venipuncture. Communications that induce negative expectations in patients can lead to the "nocebo" response, defined as experiencing greater pain. But is this also true for "sharp scratch"?

METHODS

The study was conducted across 4 U.K. hospitals. Two separate surveys of health care providers and patients explored the prevalence, phraseology, rationale, and reaction to verbal warnings before venipuncture. Blinded adult patients already attending an outpatient department during a 2-week period were randomized to hearing a "sharp scratch" or the verbal cue "ready?" immediately before venipuncture. They were also asked to rate their pain (the primary outcome).

RESULTS

77% of 117 health care providers surveyed issued a verbal warning before venipuncture; 73% used "sharp scratch". Of 62 patients surveyed, 56% agreed that "sharp scratch" accurately describes venipuncture, and 64% agreed that they prefer "sharp scratch" to no warning. With increasing age, a preference came for an alternative warning to "sharp scratch" (P = 0.039) and to be distracted by conversation (P = 0.002). Of 192 patients in the randomized study, there was no difference in pain between the "sharp scratch" and "ready" groups. The numeric rating scores were 0.74 SD 1.06 vs. 0.88 SD 1.18, respectively. (P = 0.493).

CONCLUSIONS

Most health care providers use the verbal warning "sharp scratch" before venipuncture. Most patients find this acceptable and prefer it to no warning. An exception may be elderly patients, who may prefer to be distracted by conversation. "Sharp scratch" makes no difference to the pain experienced compared with a verbal cue.