Novel methods for circumferential cryoanaesthesia: using doughnut pan or gauze.

Ice is effective for local anaesthesia but does not allow injecting without removing the ice device. This was partially solved by some recently described methods for circumferential cryoanaesthesia (CCA). CCA provides continuous anaesthesia along the peripheral part of the injection site while keeping the central part open for intervention. We describe additional novel methods for CCA using doughnut pan or gauze.

Criofacoemulsificación en la cirugía de catarata / Cryophacoemulsification in cataract surgery

Objetivo: Demostrar los resultados de la criofacoemulsificación en la cirugía de catarata, como una mejora en la calidad visual y de vida de los pacientes. Métodos: Se realizó un estudio prospectivo y analítico de serie de casos en 43 ojos con catarata. Se utilizaron técnicas estadísticas descriptivas como media y desviación estándar. En los resultados no comparados la prueba de chi cuadrado, con significación del 95 por ciento y un valor de p < 0,05 se consideró estadísticamente significativa. Resultados: El 67,44 por ciento de los pacientes no sintieron dolor y lo refirieron muy leve en la colocación del blefaróstato, en la incisión por córnea clara y durante la colocación del lente intraocular; el 62,79 por ciento fueron féminas, mayores de 70 años; el 51,16 por ciento tenía dureza nuclear NO3 por LOCSIII; la visión de colores mejoró en el 90,70 por ciento; la sensibilidad al contraste mejoró en el 58,14 por ciento; el cilindro refractivo en el 72,09 por ciento fue menor de 0,5 dioptrías; la agudeza visual mejor corregida en el 93,02 por ciento fue de 0,8 a 1,0; la paquimetría demostró diferencias significativas al final; la pérdida celular endotelial media fue de 274,16 cel. /mm2; la hexagonalidad media se redujo en un 3,42 por ciento y la encuesta FV-14 fue muy buena en el 100 por ciento de los pacientes al mes de operado. Conclusiones: La criofacoemulsificación es segura y efectiva, que disminuye los efectos inflamatorios de la cirugía sobre la córnea, con alto grado de satisfacción de los pacientes(AU)

ABSTRACT Objective: Demonstrate the effect of cryophacoemulsification in cataract surgery as a way to improve patient visual quality and quality of life. Methods: An analytical prospective study was conducted of a case series of 43 eyes with cataract. Statistical analysis was based on mean and standard deviation descriptive techniques. In results not compared, a chi-square test with 95 percent significance and p < 0.05 was considered to be statistically significant. Results: Of the patients studied, 67.44 percent did not feel any pain and reported very mild pain during blepharostat placement, clear corneal incision and intraocular lens placement; 62.79 percent were females aged over 70 years; 51.16 percent had NO3 nuclear hardness by LOCSIII; color vision improved in 90.70 percent; contrast sensitivity improved in 58.14 percent; in 72.09 percent the refractive cylinder was smaller than 0.5 diopters; in 93.02 percent best corrected visual acuity was 0.8-1.0; pachymetry showed significant differences at the end; mean endothelial cell loss was 274.16 cel/mm2; mean hexagonality was reduced 3.42 percent, and the VF-14 index was very good in 100 percent of the patients one month after surgery. Conclusions: Cryophacoemulsification is safe and effective, reduces the inflammatory effects of surgery on the cornea and achieves a high level of patient satisfaction(AU)

A propósito de la crioanestesia dental / Apropos dental cryoanesthesia

RESUMEN Introducción: La crioanestesia es una forma de anestesia tópica utilizada en procedimientos médicos menores aprovechando el descenso o inhibición del umbral doloroso causado por el estímulo térmico. Es posible emplearla en procedimientos sobre tejidos dentales para complementar la anestesia con fármacos y combatir el fracaso anestésico. Objetivo: Describir los hallazgos sobre el uso y aplicación de la crioanestesia dental en odontología. Métodos: Revisión exploratoria de la literatura científica y gris, donde se evaluó la disminución de la sensación dolorosa empleando frío sin alcanzar congelación del tejido dental. Fueron consultadas las bases de datos Pubmed, Embase, Scopus, SciELO, Elsevier y Science Direct. La búsqueda en Google Académico se realizó eliminando las entradas repetidas y limitada a los 100 primeros resultados. La investigación cubrió el periodo de 1941 hasta diciembre de 2018 y se utilizó la lista de comprobación PRISMA para ejecutar la revisión. Resultados: Cuatro artículos fueron seleccionados. Todos emplearon diferentes dispositivos, refrigerantes y escalas para valoración del dolor; sin embargo, todos reportaron ausencia de dolor en algunas de sus muestras. Conclusión: Se identificó evidencia escasa y antigua con desigualdad en las escalas de valoración, protocolos clínicos, sustancias refrigerantes y dispositivos utilizados(AU)

ABSTRACT Introduction: Cryoanesthesia is a type of topical anesthesia used in minor medical procedures. It is based on the descent or inhibition of the pain threshold caused by the thermal stimulus. Cryoanesthesia may be used in procedures performed on dental tissues to complement anesthetic drugs and combat anesthetic failure. Objective: Describe the findings about the use and application of cryoanesthesia in dental practice. Methods: An exploratory review was conducted of scientific and grey literature to evaluate pain reduction using cold temperatures without freezing the dental tissue. The databases consulted were Pubmed, Embase, Scopus, SciELO, Elsevier and Science Direct. The search in Google Scholar removed repeated entries and was limited to the first 100 results. The study covered the period extending from 1941 to December 2018, and used the PRISMA checklist to carry out the review. Results: Four papers were selected. All four used different devices, refrigerants and pain assessment scales. However, they all reported an absence of pain in some of their samples. Conclusion: Scant, outdated evidence was identified which contained discrepancies in the assessment scales, clinical protocols, refrigerant substances and devices used(AU)

Regreso al futuro en el tratamiento del dolor agudo posoperatorio / Back to the future in the treatment of postoperative acute pain

No disponible

Crioanalgesia toracoscópica: nueva estrategia para el control del dolor postoperatorio en cirugía del pectus excavatum / Thoracoscopic cryoanalgesia: A new strategy for postoperative pain control in minimally invasive pectus excavatum repair

Introducción: Publicaciones recientes reportaron el alta temprana y bajos requerimientos de opioides para el control del dolor postope-ratorio en la reparación mínimamente invasiva del pectus excavatumtras crioablación bilateral de nervios intercostales. Nuestro objetivo es describir nuestra experiencia inicial con esta técnica. Material y métodos: Análisis retrospectivo de historias clínicas de pacientes sometidos a crioanalgesia toracoscópica bilateral durante la reparación mínimamente invasiva del pectus excavatum en nuestra institución desde septiembre de 2018 a marzo de 2019. Técnica: Se aplicó una criosonda a -70°C bajo visión toracoscópica durante 2 minutos del 3º al 7º espacio intercostal, de manera bilateral. El dolor postoperatorio fue evaluado con una Escala Visual Analógica. Resultados: Se incluyeron 21 pacientes, de los cuales el 90% era de sexo masculino con una edad media de 15,2 ± 4,29 años y un peso de 53,6 ± 15,33 kg. El índice de Haller promedio fue de 5,1 ± 2,97 y el índice de corrección de 37,6 ± 13,77%. El número promedio de implantes fue de 2,55 ± 0,74. La duración media de la crioanalgesia fue de 39,9 ± 21,1 minutos. Ninguno recibió anestesia peridural. El tiempo de internación postquirúrgico fue de 1,64 ± 0,73. La necesidad de rescate con opiáceos fue menor a 1 dosis en el 71,3%. La puntuación de dolor en los días postoperatorios 1, 3, 7 y 21 fue, en promedio, de 2,55; 2,01; 0,5 y 0,06, respectivamente. Conclusiones: El empleo de la crioanalgesia toracoscópica bilateral permitió el alta hospitalaria temprana y buen control del dolor postoperatorio en todos los casos, convirtiéndose en el método analgésico de elección en nuestra práctica clínica

Objective: Recent publications report early discharge and low opioid requirements after minimally invasive pectus excavatum repair treated with bilateral intercostal nerve cryoablation. Our aim is to report our initial experience with this technique. Materials and methods: Retrospective analysis of medical records of patients undergoing bilateral thoracoscopic cryoanalgesia during minimally invasive pectus excavatum repair within our institution from September 2018 to March 2019. Technique: A cryoprobe was applied at -70 ºC for 2 minutes each from the 3rd to the 7th intercostal nerves bilaterally under thoracoscopic control. Postoperative pain was assessed using a visual analogue scale (VAS). Results: Twenty-one patients were included. Ninety percent were male, the mean age being 15.2 ± 4.29 years, and the mean weight being 53.6 ± 15.33 kg. The average Haller index was 5.1 ± 2.97, and the mean repair index was 37.6 ± 13.77%. The mean number of implants intro-duced was 2.55 ± 0.74. The mean duration of cryoanalgesia was 39.9 ± 21.1. No patients received epidural anesthesia. Mean postoperative stay was 1.64 ± 0.73 days. Seventy-one percent of the patients required 1 dose of opioids at the most for postoperative pain control. According to the VAS, the average pain score on postoperative days 1, 3, 7, and 21 was 2.55, 2.01, 0.5, and 0.06, respectively. Conclusions: Bilateral thoracoscopic cryoanalgesia during minimally invasive pectus excavatum repair leads to early discharge and good postoperative pain control in all cases. Cryoanalgesia has become our treatment of choice for pain control in the thoracoscopic repair of pectus excavatum

Alternativas anestésicas a la inyección de amidas por vía subcutánea en punciones arteriales para gasometría: una revisión sistemática / Alternatives to subcutaneous injection of amino-amide or amino-ester anesthetics before arterial puncture for blood gas analysis: a systematic review

Introducción y objetivo: La punción arterial para gasometría es una técnica dolorosa. La estrategia anestésica de elección consiste en la inyección local de amidas o esteres por vía subcutánea, pero resulta poco frecuente en algunos ámbitos asistenciales, como los servicios de urgencias. El objetivo de este trabajo es en describir las estrategias anestésicas distintas a la técnica clásica de inyección local de amidas o esteres y evaluar su eficacia en la punción arterial para gasometría. Método: Se realizó una revisión sistemática de la literatura a través de 6 bases de datos bibliográficas. Fueron seleccionados ensayos clínicos publicados entre 2000 y 2018, en inglés o español, que comparasen el dolor autopercibido por el paciente inmediatamente después de una punción arterial para gasometría en función de si se les aplicó alguna medida anestésica diferente a la inyección subcutánea de amidas o esteres frente a otro procedimiento anestésico local, un placebo o ninguna intervención anestésica. Resultados: Se localizaron 16 ensayos clínicos aleatorizados: 4 evaluaron la aplicación de anestésicos tópicos compuestos a base de esteres o amidas, 2 la punción ecoguiada, 4 el empleo de agujas de pequeño calibre o jeringuillas especiales, 1 el uso de inyectores a presión sin aguja y 5 la crioanestesia mediante hielo o aerosoles. Conclusión: Tan sólo el uso de agujas de calibre muy fino, la sustitución de jeringuillas clásicas por inyectores a presión sin aguja para la administración de amidas o esteres subcutáneas o la aplicación previa de hielo durante al menos 3 minutos se mostraron eficaces en la reducción del dolor derivado de la punción arterial para gasometría

Background and objective: Arterial puncture for blood gas analysis is a painful procedure in the emergency department (ED). Local subcutaneous injection of anesthetics containing amino amides or esters is the usual painrelief technique applied before arterial puncture, but it is little used in some care settings, such as the ED. We aimed to analyze the literature on anesthetic approaches other than the traditional one of local injection of amino-amide or amino-ester compounds for pain relief during arterial puncture and to assess the efficacy of the alternatives. Methods: A systematic review of the literature was conducted in 6 bibliographic databases. We selected randomized clinical trials (RCTs) published in English or Spanish between 2000 and 2018. The trials compared self-reported pain immediately after arterial puncture for blood gas analysis. Some form of anesthesia other than local injection of an amino-amide or -ester compound was compared to another anesthetic technique, placebo, or no anesthetic. Results: We found 16 RCTs. Four compared the effect of topical anesthetic creams containing amino amides and/or amino esters, two assessed ultrasound-guided puncture, four used small-caliber needles or special syringes, one used a needle-free high-pressure anesthetic injection system, and five studied cryoanesthesia by application of ice or aerosols. Conclusion: The only effective alternative approaches to pain relief during arterial puncture for blood gas analysis were the use of very fine-caliber needles, the use of needle-free pressure injectors for subcutaneous delivery of amino amides, and the application of ice for at least 3 minutes

Effectiveness of precooling the injection site using tetrafluorethane on pain perception in children.

BACKGROUND: Injection of local anesthesia is one of the most important reasons for avoidance behavior in children. Applying a topical anesthetic before injection is the most popular way to control pain; however, topical anesthetics have some shortcomings such as longer duration of action, displeasing taste, and spread of the anesthetic agent to noninjection site areas. Cryoanesthesia using refrigerant as a topical anesthesia is being studied as an alternative to overcome the shortcomings of topical anesthetics and has shown promising results. MATERIALS AND METHODS: In this split-mouth design study, 50 children of aged 8-10 years who required bilateral mandibular local anesthesia administration were selected. In the first visit, application of topical anesthetic spray (lidocaine) on one side and during the second appointment cryoanesthetic tetrafluorethane on the other side was used before local anesthetic administration. Patients were asked to report their discomfort and pain using visual analog scale (VAS) (subjective method). Patients' pain perception during injection is assessed by sound, eye, and motor (SEM) scale by the dentist (objective method). RESULTS: The results were statistically analyzed using paired Wilcoxon signed-rank test and Mann-Whitney tests. In VAS scale (subjective method), pain scores were significantly lower in tetrafluorethane group when compared with lidocaine group. In SEM scale (objective method), pain scores were lower in tetrafluorethane group when compared with lidocaine group, but it was statistically insignificant. CONCLUSION: Precooling the injection site using refrigerant tetrafluorethane spray has shown to be effective in eliminating pain before local anesthesia administration in children when compared with topical anesthetic lidocaine spray.

Cryoanalgesia in Patients Undergoing Nuss Repair of Pectus Excavatum: Technique Modification and Early Results.

PURPOSE: The Nuss procedure for surgical correction of pectus excavatum often causes severe postoperative pain. Cryoanalgesia of intercostal nerves is an alternative modality for pain control. We describe our modification of the cryoICE™ probe that allows for nerve ablation through the ipsilateral chest along with early results utilizing this technique. METHODS: To allow for ipsilateral nerve ablation, a 20-French chest tube was cut and secured to the cryoICE probe, thus providing insulation for the malleable end of the probe. A 3-year retrospective review of patients undergoing Nuss repair at our institution was performed. Patients who received cryoanalgesia (cryo, n = 6) were compared with a historical control cohort who did not receive cryoanalgesia (nocryo, n = 13) during Nuss repair. Hospital length of stay, postoperative narcotic requirement (PNR), and highest postoperative pain score were collected. RESULTS: Both cohorts were similar regarding age, BMI, and pectus index. The cryo group had a significantly less PNR (6.4 versus 17.9 doses, P = .05) and was discharged on average >1 day earlier than nocryo patients (3.7 versus 2.2 days, P = .01). No complications occurred in either group. CONCLUSIONS: Our technique modification simplifies previously described approaches to intercostal nerve cryoablation. Patients undergoing this adjunct benefit with less PNR and a faster discharge time.

Who is the boss? Individual recognition memory and social hierarchy formation in crayfish.

Under laboratory conditions, crayfish establish hierarchical orders through agonistic encounters whose outcome defines the dominant one and one, or more, submissive animals. These agonistic encounters are ritualistic, based on threats, pushes, attacks, grabs, and avoidance behaviors that include retreats and escape responses. Agonistic behavior in a triad of unfamiliar, size-matched animals is intense on the first day of social interaction and the intensity fades on daily repetitions. The dominant animal keeps its status for long periods, and the submissive ones seem to remember 'who the boss is'. It has been assumed that animals remember and recognize their hierarchical status by urine signals, but the putative substance mediating this recognition has not been reported. The aim of this work was to characterize this hierarchical recognition memory. Triads of unfamiliar crayfish (male animals, size and weight-matched) were faced during standardized agonistic protocols for five consecutive days to analyze memory acquisition dynamics (Experiment 1). In Experiment 2, dominant crayfish were shifted among triads to disclose whether hierarchy depended upon individual recognition memory or recognition of status. The maintenance of the hierarchical structure without behavioral reinforcement was assessed by immobilizing the dominant animal during eleven daily agonistic encounters, and considering any shift in the dominance order (Experiment 3). Standard amnesic treatments (anisomycin, scopolamine or cold-anesthesia) were given to all members of the triads immediately after the first interaction session to prevent individual recognition memory consolidation and evaluate its effect on the hierarchical order (Experiment 4). Acquisition of hierarchical recognition occurs at the first agonistic encounter and agonistic behavior gradually diminishes in the following days; animals keep their hierarchical order despite the inability of the dominant crayfish to attack the submissive ones. Finally, blocking of protein synthesis or muscarinic receptors and cold anesthesia impair memory consolidation. These findings suggest that agonistic encounters induces the acquisition of a robust and lasting social recognition memory in crayfish.

Topical cryoanesthesia for the relief of pain caused by steroid injections used to treat hypertrophic scars and keloids.

Intralesional steroid injections are the standard treatment for hypertrophic scars and keloids. The procedure is, however, quite painful and is unpopular with patients because of this. Topical application of anesthetic creams, such as Ametop gel (tetracaine) and EMLA cream (lidocaine and prilocaine), has limited efficacy because of poor drug penetration. The onset of the analgesic effect is also slow, which means that the use of topical anesthetics is time-consuming in clinical practice.We hypothesized that a commercially available cryotip could be used to provide fast-acting topical cryoanesthesia that would reduce the pain associated with steroid injections.Thirty patients with hypertrophic scars or keloids were enrolled in the study. Scars were injected with the steroid, triamcinolone acetonide, with or without prior application of the cryotip (-10 °C) for 15 seconds. The degree of pain was evaluated in each case using the visual analogue scale (VAS) and the verbal descriptor scale (VDS), together with any side-effects caused by application of the cryotip.The VAS pain scores showed a statistically significant (P < .01) difference between the pretreated and the control scars (pain scores 7.87 ±â€Š1.31 and 2.7 ±â€Š1.37, respectively). The VDS pain scores also showed a statistically significant (P < .01) difference between the pretreated and the control scars. And its average scores were 7.89 ±â€Š0.32 and 2.68 ±â€Š0.25, respectively.Application of the cryotip before injection could provide a rapid and effective means of reducing the pain associated with steroid injections. Painless would result in better therapeutic effect.

Prospective, double blind, randomized, controlled trial comparing vapocoolant spray versus placebo spray in adults undergoing intravenous cannulation.

OBJECTIVES: Painful diagnostic and therapeutic procedures are common in the health care setting. Eliminating, or at least, minimizing the pain associated with various procedures should be a priority. Although there are many benefits of providing local/topical anesthesia prior to performing painful procedures, ranging from greater patient/family satisfaction to increased procedural success rates; local/topical anesthetics are frequently not used. Reasons include the need for a needlestick to administer local anesthetics such as lidocaine and the long onset for topical anesthetics. Vapocoolants eliminate the risks associated with needlesticks, avoids the tissue distortion with intradermal local anesthetics, eliminates needlestick pain, have a quick almost instantaneous onset, are easy to apply, require no skills or devices to apply, are convenient, and inexpensive. The aims of this study were to ascertain if peripheral intravenous (PIV) cannulation pain would be significantly decreased by using a vapocoolant (V) versus sterile water placebo (S) spray, as determined by a reduction of at least ≥1.8 points on numerical rating scale (NRS) after vapocoolant versus placebo spray, the side effects and incidence of side effects from a vapocoolant spray; and whether there were any long term visible skin abnormalities associated with the use of a vapocoolant spray. MATERIALS AND METHODS: Prospective, randomized, double-blind controlled trial of 300 adults (ages 18-80) requiring PIV placement in a hospital ED, randomized to S (N=150) or V (N=150) prior to PIV. Efficacy outcome was the difference in PIV pain: NRS from 0 (none) to worst (10). Safety outcomes included a skin checklist for local adverse effects (i.e., redness, blanching, edema, ecchymosis, itching, changes in skin pigmentation), vital sign (VS) changes, and before/after photographs of the PIV site. RESULTS: Patient demographics (age, gender, race), comorbidity, medications, and vital signs; and PIV procedure variables (e.g., IV needle size, location, number of IV attempts, type and experience of healthcare provider performing the IV) were not significantly different for the two groups. Median (interquartile range) PIV pain was 4 (2, 7) (S) and 2 (0, 4) (V) (P<0.001). Skin checklist revealed minimal erythema: S 0% (N=0/150), V: 2.7% (4/150), which resolved within 5min, and no blanching, skin pigmentation changes, itching, edema, or ecchymosis. Photographs at 5-10min revealed no visible skin changes in any patient (N=300), vapocoolant (N=150) or placebo groups (N=150). Complaints (N=26) were coolness/cold feeling S 8.7% (N=13), V 7.3% (N=11), coolness/numbness S 0% (N=0), V 0.7% (N=1), and burning S 0.7% (N=1), V 0 (0%). Patient acceptance of the vapocoolant spray was high: 82% (123/150) of the patients stated they would use the spray in the future, while only 40.7% (61/150) of the placebo group stated they would use the placebo spray in the future. CONCLUSIONS AND IMPLICATIONS: Vapocoolant spray significantly decreased peripheral intravenous cannulation pain in adults versus placebo spray and was well tolerated with minor adverse effects that resolved quickly. There were no significant differences in vital signs and no visible skin changes documented by photographs taken within 5-10min postspray/PIV.

Anestesia subcutánea o tópica en la gasometría arterial / Subcutaneous or topical anesthesia for arterial blood gas test

Objetivo: determinar qué tipo de anestésico local, subcutáneo o tópico es más eficaz para disminuir el dolor durante la realización de la gasometría arterial en mayores de 18 años. Metodología: revisión narrativa de la literatura. Las bases de datos utilizadas para la búsqueda bibliográfica fueron Scopus, Medline, Cochrane Library y Cuiden, limitada a los años 2005-2015 y a artículos publicados en inglés y castellano, mediante combinación de términos MeSH y texto libre con operadores booleanos. Resultados: se obtuvieron 11 artículos (tres revisiones, un estudio cuasiexperimental y siete ensayos clínicos). Cuatro de los artículos afirmaban que la lidocaína subcutánea reducía el dolor, tres que lo reducía la crioanestesia y seis afirmaron que la anestesia tópica mediante cremas no reducía el dolor. Conclusiones: la lidocaína subcutánea es eficaz en la reducción del dolor. En relación con la anestesia tópica hay indicios de que la crioanestesia pueda dar buenos resultados. La administración de crema no es efectiva. Son necesarios estudios comparativos entre los diferentes tipos de anestesia, así como estudios sobre crioanestesia (AU)

Objective: to determine the type of local anesthesia, either subcutaneous or topical, that is more effective in order to reduce pain during an arterial blood gas test in >18-year-old patients. Methodology: a narrative review of literature. The databases used for bibliographic search were Scopus, Medline, Cochrane Library and Cuiden, limited to the years 2005 to 2015, and articles in English and Spanish, through combination of MeSH terms and free text with Boolean operators. Results: eleven (11) articles were obtained (three reviews, a quasi-experimental study, and seven clinical trials). Four of the articles stated that subcutaneous lidocaine reduced pain, three stated that pain was reduced through cryoanesthesia, and six claimed that topical anaesthetic creams did not reduce pain. Conclusions: subcutaneous lidocaine is effective in pain reduction. Regarding topical anesthesia, there is initial evidence that cryoanesthesia could offer good results. Cream administration is not effective. It is necessary to conduct comparative studies between different types of anesthesia, as well as studies on cryoanesthesia (AU)

Vapocoolant Spray Effectiveness on Arterial Puncture Pain: A Randomized Controlled Clinical Trial.

Arterial blood gas (ABG) sampling is a painful procedure with no perfect technique for quelling the discomfort. An ideal local anesthesia should be rapid, easy to learn, inexpensive, and noninvasive. This study was aimed to compare pain levels from ABG sampling performed with vapocoolant spray in comparison to placebo. We hypothesized that pretreatment with the vapocoolant would reduce the pain of arterial puncture by at least 1 point on a 10 point verbal numeric scale. We have evaluated the effectiveness of a vapocoolant spray in achieving satisfactory pain control in patients undergoing ABG sampling in this randomized placebo controlled trial. Eighty patients were randomized to 2 groups: group A, who received vapocoolant spray, and group B, who received water spray as placebo (Control group). Puncture and spray application pain was assessed with numerical rating scale (0, the absence of pain; 10, greatest imaginable pain) and number of attempts was recorded. The pain score during ABG sampling was not lower in group A compared with group B significantly (4.78±1.761 vs. 4.90±1.837; P:0.945). This study showed that while the spray exerts more application pain, the number of attempts required for ABG sampling was not significantly lower in group A compared with group B (1.38±0.54 vs. 1.53±0.68; P=0.372). Vapocoolant spray was not effective in ABG pain reduction, had milder application pain compared to placebo (P<0.05), but did not reduce sampling attempts. At present, this spray cannot be recommended for arterial puncture anesthesia, and further study on different timing is 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.

Effect of topical vapocoolant spray on perioperative pain response of unweaned calves to ear tagging and ear notching.

OBJECTIVE: To evaluate the efficacy of a vapocoolant spray to provide local anaesthesia for calves during ear tagging and ear notching. STUDY DESIGN: Randomized study. ANIMALS: Twenty Black Angus calves aged 4-16 weeks old. METHODS: Temperature validation studies using thermocouples and a temperature data logger were conducted on dead and live tissue to determine optimal spray distance and duration to achieve tissue anaesthesia (<10 °C). A behavioural trial was conducted to assess efficacy for ear tagging and ear notching. Calves (n = 20) were randomly assigned to the vapocoolant spray (VS) or the water spray (WS) group. A 3 second spray was administered from 10 cm to both sides of the ear immediately prior to ear tagging and ear notching. A numerical rating scale (NRS) was used to score behavioural response to each procedure, with responses categorized from 0 (no response) to 3 (severe). RESULTS: Temperature and tissue validation studies indicated that a vapocoolant spray reduced dead and live tissue temperature to below nociceptive threshold levels (10 °C) for 10-16 seconds. Univariate analysis indicated that ear notching was more painful than ear tagging [odds ratio (OR) = 19.2, 95% confidence interval (CI): 5.34-68.99, p < 0.001]. When adjusted for the multivariate model, there was a significant effect of treatment, with WS calves showing higher pain response scores than VS calves (OR = 4.08, 95% CI: 1.34-12.42, p = 0.011). Ear notching resulted in greater pain response scores than ear tagging (OR = 23.19, 95% CI: 6.18-87.05, p < 0.001). CONCLUSIONS: and clinical relevance Vapocoolant spray induced local anaesthesia and significantly reduced the pain response to ear tagging and ear notching in calves. Ear notching is more painful than ear tagging. Cryoanaesthesia is an effective option for reducing the perioperative pain associated with these simple husbandry procedures.