The efficacy and acceptability of using a jet injector in performing digital blocks

Mechanism and clinical applications of needle-free injectors in dermatology: Literature review

BACKGROUND

Needle-free jet injectors are devices that deliver drugs using a high-speed jet without a needle. Recent studies have significantly increased our understanding of the mechanisms of needle-free jet injectors, and technical advancements have broadened the scope of application of the device.

AIMS

We aimed to provide an up-to-date review of previous literature regarding the mechanism of action and clinical applications of needle-free jet injectors in dermatology field.

METHODS

We conducted a PUBMED search for studies on needle-free jet injectors using the following parameters: "Pneumatic injector" OR "needleless injector" OR "needle-free injector" OR "jet injector." Among 191 results, 72 articles focusing on their mechanisms of action, cutaneous delivery patterns, and clinical applications in dermatology were selected for review.

RESULTS

Significant clinical evidence has been published confirming the potential of needle-free jet injectors in treating various dermatologic conditions. In particular, these devices have the potential to be used in various skin remodeling treatment, especially in skin rejuvenation procedures by injecting various esthetic materials.

CONCLUSION

As proven by accumulated experience, the applications of NFJIs are not restricted to vaccine or insulin delivery in dermatology field. However, this literature review shows that until now, there are no clinical guidelines that standardize the optimal parameters when using NFJIs on various clinical settings. Therefore, further studies should be performed in order to investigate the full potential of these devices in dermatology, to ensure safe and effective outcomes in clinical practice.

No-needle local anesthesia for adult male circumcision

PURPOSE

We used a local anesthetic jet injection technique for adult male circumcision. This method eliminates needle use and may decrease the fear of local anesthetic injection used for male circumcision.

MATERIALS AND METHODS

We recruited 60 men seeking voluntary adult male circumcision into the study from June to September 2009. We used a MadaJet Medical Injector to deliver a high pressure spray of 0.1 ml 2% plain lidocaine solution directly through the penile skin circumferentially around the proximal third of the penis. All men underwent circumcision using the Shang Ring and were evaluated for anesthetic safety, efficacy and acceptability. Pain was measured on a visual analog scale.

RESULTS

The average volume of 2% lidocaine anesthetic solution delivered by jet injection was 0.1 ml with a mean total of 0.9 ml per circumcision procedure. More than 85% of men did not require supplemental anesthesia. Anesthetic onset required approximately 45 seconds from the time that injections were completed. Mean pain scores for immediate postoperative, 24-hour postoperative, ring removal and post-ring removal events were 0.1, 6.8, 2.2 and 0.9, respectively. In 4 patients (6.67%) mild urethral bleeding resolved with pressure, resulting in technique modification.

CONCLUSIONS

No-needle jet injection is safe and effective for adult MC. The technique efficiently delivers local anesthesia with rapid onset in men undergoing circumcision. This needle-free approach may enhance the popularity of adult male circumcision.

A systematic review of measures for reducing injection pain during adult immunization

OBJECTIVE

To evaluate the effectiveness of different pain-relieving interventions to reduce pain from immunization in adults.

DATA SOURCES

MEDLINE (1950 to October Week 3 2008) PsycINFO (1967 to December Week 1 2008), CINAHL (1982 to October Week 4 2008), EMBASE (1980 to 2008 Week 43) and the Cochrane Central Register of Controlled Trials (3rd Quarter 2008).

REVIEW METHODS

Databases were searched for trials of pharmacological, behavioural, physical or operator-dependant techniques to reduce pain from immunization in adults. The primary outcome was pain as assessed by visual analogue scale or other numeric rating scale.

RESULTS

Six studies representing 853 participants were identified. One study evaluating pharmacological interventions (lidocaine-prilocaine) found them to be effective in reducing pain from immunization. Similarly, two studies evaluating physical pain relieving techniques, either skin cooling interventions (Fluori-Methane) or tactile stimulation (manual pressure at the site of injection) found them to reduce pain. One study of jet injectors found them to be more painful than conventional needle and syringe. Neither freezing needles nor warming vaccines was found to be effective in reducing pain. No studies investigated psychological interventions or oral analgesics (acetaminophen and ibuprofen).

CONCLUSION

There was limited evidence to support the use of lidocaine-prilocaine, Fluori-Methane and manual pressure for reducing immunization pain in adults. There was limited evidence of more pain with jet injectors compared to needle and syringe. Due to limited data, we recommend further investigation of methods to reduce immunization pain in adults, primarily psychological and physical techniques.

Needle-free delivery of lidocaine for reducing the pain associated with the fine-needle aspiration biopsy of thyroid nodules: time-saving and efficacious procedure

OBJECTIVE

Fine-needle aspiration biopsy (FNAB) is a mandatory procedure in evaluation of thyroid nodules. However, it is sometimes perceived as a painful procedure by the patients. Efficacy of the needle-free injection of local anesthesia for reducing the pain associated with other cutaneous procedures that involve needle insertion was previously reported. In this double-blind, placebo-controlled clinical trial, we evaluated the effectiveness of a needle-free injection of lidocaine in achieving satisfactory pain control in patients undergoing FNAB of thyroid nodules.

DESIGN

Patients were allocated to receive either lidocaine administered by needle-free injection system (n = 55) or placebo (isotonic saline) (n = 52) 2-3 minutes before FNAB. A series of four aspirations of each nodule was performed. The patients rated pain associated with the procedure according to a 100-mm visual analog scale (VAS), an 11-point numeric rating scale (NRS), and a four-category verbal rating scale (VRS).

MAIN OUTCOME MEASURE

The two groups studied were similar with respect to age, sex, thyroid volume, nodule size, and nodule site. When the effectiveness of lidocaine was compared with that of placebo, the mean VAS score was 11.4 +/- 13.6 mm versus 38.2 +/- 35.5 mm (p < 0.0001) and the mean NRS score was 1.4 +/- 1.5 points versus 3.9 +/- 2.6 points (p < 0.0001), respectively. The absolute numbers according to VRS score in each group was also significantly different (p < 0.0001). The percentage of patients with "no pain" or "mild pain" in the lidocaine group (90.9%) was significantly higher than that in the placebo group (44.2%) (p < 0.0001). Less than 10% of the patients in lidocaine group experienced moderate pain and none experienced severe pain. No adverse treatment-related effects were observed.

CONCLUSIONS

To our knowledge, this is the first study demonstrating that the needle-free delivery of lidocaine is an effective, useful, and noninvasive method of providing local anesthesia for the FNAB of thyroid nodules.

No-needle jet anesthetic technique for no-scalpel vasectomy

PURPOSE

We describe a new, modified jet injection technique for local anesthesia for no-scalpel vasectomy without the use of a needle, which may minimize the fear of vasectomy in men due to the needle involved in local anesthesia.

MATERIALS AND METHODS

A MadaJet Medical Injector (MADA Medical Products, Carlstadt. New Jersey) was used in this study to deliver a high pressure spray of 0.1 cc local anesthetic solution directly through the scrotal skin down onto the tissue around the vas. Two or 3 jet injections are delivered to each vas and a total of 4 to 6 suffice for the entire vasectomy.

RESULTS

No-needle jet injection is remarkably effective for local anesthesia for no-scalpel vasectomy. The average volume of anesthetic solution per jet injection is 0.1 cc with 0.2 to 0.3 cc for each vas. Onset is almost immediate, within 10 to 20 seconds after injection. About 465 patients were anesthetized by the jet injection technique with great satisfaction. The average visual analog scale score for the pain of the jet injection itself was 1.71 of 10. The average visual analog scale score for the pain of subsequent vasectomy during the surgical procedure was 0.66 of 10 (median 0.2). No hematomas were noted. Patients experience the mild discomfort of a pinch, not unlike a rubber band, with the first injection.

CONCLUSIONS

No-needle anesthesia with jet injection is a new technique to deliver rapid onset of profound local anesthesia to the patient undergoing vasectomy. It is a simple and safe approach with high patient satisfaction, as reflected in low pain scores. The benefit of this technique without a needle is that it may decrease the fear of pain in men and enhance the popularity of vasectomy worldwide.

Subcutaneous lidocaine delivered by jet-injector for pain control before IV catheterization in the ED: the patients' perception and preference

To evaluate patients' perceptions and preferences concerning pain control during intravenous (IV) catheterization, a sample of 50 adult patients received subcutaneous lidocaine (0.2 mL 1%) by jet injector, or no anesthetic with a sham injection before IV catheterization. Visual analog scale (VAS), pain intensity score (PIS), and adverse reactions were recorded. A significant difference existed in the scores of patients who received lidocaine versus those who did not VAS (P <.001) PIS (P <.004). Patients' receiving lidocaine via jet-injector experienced more minor and potentially preventable adverse effects such as mild bruising and trauma to the veins. Patients in both groups (84% overall) preferred local anesthesia based on this experience. Using the jet-injector to provide local anesthesia before IV catheterization in the ED is effective, fast, and does not require sharps disposal and handling precautions.

Potential for cross-contamination from use of a needleless injector

BACKGROUND

Medical devices that are used on patients in fields containing potentially infectious body fluids can become contaminated and transmit infectious agents to other sites on the patient or to other patients if the devices are not properly cleaned and decontaminated after use on each patient treatment site. One such device is the needleless or jet injector, which is widely used in medicine and dentistry to deliver local anesthetic in procedures such as bone marrow aspirations, lumbar punctures, and cutaneous and intraoral injections. This study was conducted to determine whether cross-contamination can occur on in vitro reuse of a needleless injector and whether a manufacturer's recommended method of injector decontamination (ie, immersion sterilization) is effective in the prevention of cross-contamination.

METHODS

The study was performed with new autoclaved injectors, fluorescein dye, and Streptococcus crista (the bacteria commonly found in saliva) in the field of use to determine whether these devices can become contaminated during use and carry over the contamination to other sites during immediate reuse.

RESULTS

Fluorescein dye and bacteria tests with the needleless injectors showed that contamination or carryover does occur. It appeared to reduced to a minimum when a autoclaved, sterile rubber cap used over the head of the device during injection was replaced between each use, although replacement of the rubber cap alone did not prevent carryover. Immersion of the head of the injector in a 2% glutaraldehyde solution for 30 minutes followed by a sterile water rinse and the replacement of the rubber cap with a sterile cap between uses was shown to curtail bacterial growth and prevent cross-contamination on immediate reuse of the device.

CONCLUSION

This study demonstrated that needleless injectors become contaminated during in vitro use and direct contact with contaminated surfaces and that needless injectors carry over the contamination to subsequent sites of release. The replacement of the injector's rubber cap with a new one after initial discharge or the removal of an exposed rubber cap and immersion of the head of the injector in 2% glutaraldehyde followed by a rinse of the head in sterile water, as recommended by one injector manufacturer, can minimize or eliminate the carryover.

Evaluation of a no-needle penile injector: a preliminary study evaluating tissue penetration and its hemodynamic consequences in the rat

OBJECTIVES

Intracavernous needle injection is an effective delivery method for pharmacotherapy of erectile dysfunction. Needle phobia, pain, and concern about local tissue injury have stimulated the search for new, less invasive means of inducing penile erection. In this preliminary communication, we evaluate a jet injector as an alternative to needle injection for intracavernous delivery of vasoactive drugs.

METHODS

Jet injection was evaluated in three groups of rats receiving either India ink, saline, or papaverine into the penis. The ability of the jet injection to penetrate through the tunica albuginea and deliver liquid to the corpora cavernosa smooth muscle was assessed by the degree of staining within the corpus cavernosum (ink group), histologic change (saline group), and rise in intracavernous pressure (papaverine group). Erectile capacity following cavernous nerve electric stimulation was compared before and 1 hour after injection of saline or papaverine.

RESULTS

Ink traversed the skin and tunica albuginea with extensive deposition noted within the cavernous spaces. Varying degree of subcutaneous hemorrhage were seen with saline jet injection; however, the corpus cavernous smooth muscles showed no evidence of injury. Jet injection of papaverine 3250 micrograms significantly increased cavernous pressure (39.4 +/- 4.6 cm H2O) compared with saline injection (2.8 +/- 1.3 cm H2O).

CONCLUSIONS

We conclude that acute jet injection is an effective method for intracavernous delivery of drugs. Long-term effects should be evaluated prior to clinical use.