Efficacy of ShotBlocker device versus vapocoolant spray for spinal needle pain relief during spinal anaesthesia in elective caesarean section - A randomised controlled trial

Background and Aims

Apprehension of pain due to a spinal needle is often a cause of anxiety and refusal. ShotBlocker provides non-painful physical stimulation, inhibiting pain perception. The vapocoolant spray contains ethyl chloride vapours, rapidly raising the skin temperature and hampering the transmission of noxious stimuli. The present study compared the effectiveness of the ShotBlocker device and the vapocoolant spray in reducing spinal needle-associated pain in primigravida women undergoing elective lower-segment caesarean section (LSCS).

Methods

We enroled 144 primigravida women undergoing elective LSCS and were randomised to Group SB (the ShotBlocker device was firmly pressed over the skin, and the spinal needle was inserted through its slit), Group V (the vapocoolant spray was applied at the puncture site before spinal needle insertion), and Group C (received local infiltration before spinal anaesthesia (SA)). The groups were compared for needle-associated pain and patient satisfaction using a 10-point visual analogue scale (VAS) and a 3-point Likert scale.

Results

The mean (standard deviation) [95% confidence interval (CI)] VAS scores of Group SB 3.85 (0.74) [3.64, 4.07] and Group V 3.04 (0.74) [2.83, 3.26] were significantly lower than that of Group C 5.19 (0.92) [3.28, 3.62]). On the Likert scale, the maximum number of patients in the vapocoolant group (64.6%) responded satisfactorily, while in the control group, the majority (62.5%) of participants responded dissatisfied (P < 0.001).

Conclusion

Both the ShotBlocker and vapocoolant spray reduce needle puncture-associated pain before SA in primigravida patients undergoing elective LSCS. However, the vapocoolant spray is more beneficial in reducing spinal needle-associated pain than the ShotBlocker device.

Recognizing Ethyl Chloride Neurotoxicity: Inhalant Abuse Hidden in Plain Sight

Ethyl chloride is a common topical anesthetic. However, when abused as an inhalant, effects can range from headaches and dizziness to debilitating neurotoxicity requiring intubation. While previous case reports describe the short-term reversible neurotoxicity of ethyl chloride, ours show chronic morbidity and mortality outcome. During the initial evaluation, it is essential to consider the rising trend of commercially available inhalants being used as recreational drugs. We present a case of a middle-aged man presenting with subacute neurotoxicity due to repeated abuse of ethyl chloride.

Reversible Neurotoxicity Due To Excessive Use of Ethyl Chloride

BACKGROUND

Ethyl chloride is commercially available as a DVD/VCR cleaner, and can be found as a gasoline additive and topical anesthetic. There is an emerging trend of recreational huffing to enhance sexual relations. Neurotoxicity from repeated abuse is uncommon.

CASE REPORT

A 36-year-old man with a history of intermittent ethyl chloride use for 15 years presented to the Emergency Department with an inability to walk for 4 days after frequent use for 1 week. The patient reported a rapid titration of inhalation from zero to eight cans of 4.6 oz ethyl chloride aerosol per day over a 1-week period. Initial vital signs were heart rate 88 beats/min, blood pressure 147/60 mm Hg, temperature 37.2°C (99°F), and respiratory rate 16 breaths/min. Physical examination was notable for slurred speech, ptosis, a wide-based and ataxic gait with short strides, inability to stand without support, loss of toe/finger proprioception, horizontal and vertical nystagmus, and dysmetria on coordination testing. Strength and sensation were preserved. His work-up included computed tomography and magnetic resonance imaging of the brain, cervical, thoracic, and lumbar spine that demonstrated no acute abnormalities. On hospital day 9, the patient was able to ambulate with mild difficulty. WHY SHOULD AN EMERGENY PHYSICIAN BE AWARE OF THIS?: Toxicity from excessive ethyl chloride huffing has been rarely reported. The toxicity was characterized with cerebellar findings, no attributable laboratory abnormalities, and no radiographic abnormalities on computed tomography/magnetic resonance imaging. The neurotoxicity resolved with supportive care. This case of excessive huffing of ethyl chloride presenting with neurotoxicity and ataxia further characterizes a rare complication of ethyl chloride toxicity that is gaining popularity.

Sterility of Ethyl Chloride Spray After Use in the Clinic

Background: Ethyl chloride spray is used frequently in the outpatient setting as a local anesthetic for injections and aspirations with varying consensus about the sterility of the spray. We hypothesize that ethyl chloride spray remains sterile and would show no bacterial growth during routine clinical use. Methods: Thirteen ethyl chloride bottles were collected for testing. Two unopened bottles were used as controls. Eleven unopened bottles were placed in orthopedic clinics and recollected after varying duration of use. The final volume and duration of use were recorded. Each bottle was sprayed in a separate test tube and allowed to evaporate. Trypticase soy broth was added to each tube and incubated for 48 hours. Control test tubes with broth alone were prepared and incubated under the same conditions. Cultures were evaluated at 24 and 48 hours. Results: The mean duration of ethyl chloride bottle use prior to culturing was 26 days. The average volume used per day was 1.9 mL. Each ethyl chloride bottle had an initial volume of 103.5 mL. Using the average daily volume usage, an extrapolated lifespan of each bottle was estimated at 7.7 weeks. None of the samples showed bacterial or fungal growth at 24 or 48 hours. Conclusion: Ethyl chloride bottles used in the clinical settings showed no bacterial or fungal contamination through their shelf life and routine use. The duration and amount of use did not affect sterility. Although the antimicrobial activity of ethyl chloride spray on skin is debated, ethyl chloride itself remains sterile through clinical use.

Effectiveness of Different Techniques of Ethyl Chloride Spray for Venepuncture-Induced Pain: A Randomised Controlled Trial

Background:

Venepuncture is an essential component of anaesthesia services. However, this invites pain generating the first negative experience with anaesthesia. Hence, relief of this pain carries considerable importance. Efficacy of ethyl chloride spray although studied, there is no consensus for the best way of application.

Objectives:

The present study was conducted to find an effective technique/method of ethyl chloride spray application to reduce venepuncture pain.

Methods:

Adult patients posted for different anaesthesia procedures were randomised into three groups. Venepuncture was done either after installation of distilled water or spray of ethyl chloride either once to twice. Venepuncture pain was assessed with a 0-100 Numeric Rating Scale.

Results:

The analysis showed significant differences among the groups (F [2,96] = 66.27, P < 0.05). The twice sprayed group experienced the least pain ([mean ± standard deviation [SD]] 16.67 ± 10.21), lower in the once spray group ([mean ± SD] 27.58 ± 13.24), and the controls had the highest pain score ([mean ± SD] 49.09 ± 11.28). Post hoc Tukey's tests showed all the three groups differed significantly. The effect size was large, and the variability of the spray on the reduction of pain scores is 58% (η² = 57.99).

Conclusion:

Ethyl chloride spray effectively reduces the pain on venepuncture, especially when the vapocoolant is sprayed twice each over 5 s, and from a distance of 5 cm perpendicular to the skin.