Parosmia for Pediatric Anesthesia

Overseen By Colleen Mennie, RN

Age: < 18

Sex: Any

Trial Phase: Academic

Sponsor: Johns Hopkins University

Disqualifiers: Emergent surgery, NPO status, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Approved in 4 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 2

Duration: perioperative period

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial aims to determine if altering the smell of anesthesia can reduce stress in children before surgery. Children often feel anxious due to the unpleasant smell of the anesthesia mask. By using parosmia (altering smell perception), the trial seeks to make the mask smell more pleasant, improving cooperation and reducing anxiety. Children aged 5-12 who are scheduled for surgery and are generally healthy may be suitable candidates for this study. The trial will compare the new smell-changing method with the usual anesthesia process to identify which is more effective. As an unphased trial, this study provides a unique opportunity to contribute to innovative research that could make surgery less stressful for children.

Will I have to stop taking my current medications?

The trial information does not specify whether participants need to stop taking their current medications.

What prior data suggests that this method is safe for pediatric anesthesia?

Research has shown that sevoflurane, a key component of the treatment, effectively helps children fall asleep quickly for surgery due to its mild scent and rapid action. It is commonly used in pediatric anesthesia. Safety data from a large study revealed that out of more than 21 million reports, only 474 cases identified sevoflurane as the main cause of any side effects, indicating that serious side effects are quite rare.

Possible side effects include laryngospasm, where the vocal cords suddenly close, but this can be treated if it occurs. Overall, sevoflurane is well-tolerated and widely used in children, making it a reliable choice for anesthesia. The concept of parosmia, which alters smell perception, is a new approach aimed at making the experience more pleasant for children. While more research is needed, current evidence indicates that this method is safe and could help reduce stress during procedures. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about this technique because it introduces a playful and comforting element to pediatric anesthesia. Unlike traditional methods that might feel intimidating or uncomfortable for children, this approach involves telling kids about a "magical machine" that can make the anesthesia mask smell like their favorite flavor. This imaginative experience could make the anesthesia process less stressful for young patients, potentially leading to more cooperation and smoother inductions. By engaging a child's senses and imagination, this method aims to transform a routine medical procedure into something less scary and more interactive.

What evidence suggests that parosmia is effective for reducing perioperative stress in children?

This trial will compare two approaches for inhalation induction in pediatric anesthesia. Research has shown that altering scent perception can help children feel more comfortable during anesthesia. This is particularly useful in making the smell of sevoflurane, a common anesthetic, more pleasant. In this trial, one group will experience an experimental approach where children choose the scent of their mask, potentially increasing their willingness to wear it. However, previous research has faced limitations, such as small study sizes and lack of random selection. While more studies are needed, this method appears promising in reducing anxiety for children undergoing surgery. ^{1 2 6 7 8}

Who Is on the Research Team?

Pooja O'Neil, MD

Principal Investigator

Johns Hopkins School of Medicine

Are You a Good Fit for This Trial?

This trial is for children aged 5-12 who are in good health (ASA I and II) and coming from home. It's designed to see if changing the smell of anesthesia can make kids less scared when they're put to sleep for surgery.

Inclusion Criteria

I am between 5 and 12 years old.

I am currently living at home.

I am in good or mild systemic disease according to ASA classification.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

Treatment

Participants undergo inhalation induction with either parosmia or standard method

perioperative period

1 visit (in-person)

Follow-up

Participants are monitored for perioperative anxiety and post-operative outcomes

<2 hours post-operatively

1 visit (in-person)

What Are the Treatments Tested in This Trial?

Interventions

• Inhalation induction with parosmia

Trial Overview

The study tests whether using parosmia, which changes how smells are perceived, can help kids cooperate better during inhalation inductions with sevoflurane—anesthesia gas—by making it smell nicer.

How Is the Trial Designed?

Group I: Inhalation induction with parosmia Experimental Treatment 1 Intervention

The experimental group will be told about a magical machine that can change the smell of the mask to any flavor the patient desires. The participant will be asked to take a deep breath thinking about that smell and then sevoflurane will be introduced. The patient will be asked if the the chosen flavor is smelled and the response will be noted.

Group II: Standard inhalation induction Active Control 1 Intervention

Standard inhalation induction.

Inhalation induction with parosmia is already approved in United States, European Union, Canada, Japan for the following indications:

Approved in United States as Sevorane for:

• Induction and maintenance of general anesthesia in adult and pediatric patients for inpatient and outpatient surgery

Approved in European Union as Sevorane for:

• Induction and maintenance of general anesthesia in adult and pediatric patients for inpatient and outpatient surgery

Approved in Canada as Sevorane for:

• Induction and maintenance of general anesthesia in adult and pediatric patients for inpatient and outpatient surgery

Approved in Japan as Sevorane for:

• Induction and maintenance of general anesthesia in adult and pediatric patients for inpatient and outpatient surgery

Who Is Running the Clinical Trial?

Johns Hopkins University

Lead Sponsor

Trials

2,366

Recruited

15,160,000+

Published Research Related to This Trial

A systematic review of four randomized controlled trials involving pediatric anesthesia found no significant difference in perioperative respiratory adverse events between inhalational and intravenous induction methods.

However, inhalational induction was associated with a higher risk of respiratory adverse events in children with multiple risk factors, suggesting that careful consideration is needed when choosing induction methods for at-risk pediatric patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Respiratory and hemodynamic perioperative adverse events in intravenous versus inhalational induction in pediatric anesthesia: A systematic review and meta-analysis. Porter, LL., Blaauwendraad, SM., Pieters, BM.[2021]

In a study involving 102 pediatric patients, sevoflurane was found to have a higher incidence of emergence agitation compared to halothane during recovery from anesthesia, indicating a potential drawback in its use for pediatric procedures.

Despite its rapid induction and recovery benefits, the study highlights the need for caution with sevoflurane due to its association with postoperative excitement, which may affect patient comfort after surgery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Sevofluran in pediatric practice--personal experience]. Kobylarz, K., Kołaczyk, D., Stańczyk, M.[2018]

In a study involving 143 adult patients, sevoflurane was found to allow for a quicker recovery from general anesthesia compared to isoflurane, with shorter times for extubation, eye opening, and command response.

Both sevoflurane and isoflurane demonstrated similar safety profiles, as there were no significant differences in renal and hepatic function before and after surgery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Maintenance and recovery characteristics of sevoflurane anaesthesia in adult patients. A multicenter, randomized comparison with isoflurane. Ranieri, R., Martinelli, G., Pagani, I., et al.[2018]

In a study involving 41 children aged 3-10 years, using fruit flavoring to disguise the odor of isoflurane during inhalational induction resulted in significantly quieter behavior compared to a placebo, although movement levels remained unchanged.

Despite the improvement in quietness, there were no differences in respiratory complications or overall quality of induction as assessed by the anaesthetist, indicating that while the flavoring may help with comfort, its impact on safety and efficacy needs further investigation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

'Fruit-flavoured' mask for isoflurane induction in children. Lewis, RP., Jones, MJ., Eastley, RJ., et al.[2013]

In a study involving 120 pediatric patients aged 3 to 10 years, sevoflurane at a concentration of 6% was found to provide a faster induction of anesthesia with fewer adverse effects compared to higher concentrations.

While higher concentrations of sevoflurane (8%) led to a higher incidence of airway reflex responses, the decrease in blood pressure remained within a safe range across all concentrations, indicating that 6% is the most practical choice for effective and safe inhalation induction.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comparison of inhalation induction with 2%, 4%, 6%, and 8% sevoflurane in nitrous oxide for pediatric patients. Hsu, YW., Pan, MH., Huang, CJ., et al.[2018]

A new method called troposmia was developed to help children enjoy the smell of sevoflurane during inhalational induction, resulting in significantly fewer children resisting the facemask (1 out of 32 in the troposmia group compared to 9 out of 32 in the control group).

Most children in the troposmia group reported that the smell of the facemask changed as they requested, indicating that this technique can enhance their experience and cooperation during anesthesia induction.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Distorted perception of smell by volatile agents facilitated inhalational induction of anesthesia. Fukumoto, M., Arima, H., Ito, S., et al.[2018]

In a study of 64 children aged 3-12 undergoing surgery, sevoflurane provided a faster recovery from anesthesia compared to halothane, with shorter times for purposeful movements (9 min vs. 15.5 min) and readiness for discharge (18 min vs. 30 min).

Sevoflurane also demonstrated better cardiovascular stability during induction, making it a potentially safer alternative to halothane for pediatric anesthesia.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A prospective, randomized clinical comparison of sevoflurane and halothane in children. Villani, A., Zuccoli, P., Rovella, C., et al.[2018]

Sevoflurane is preferred over halothane for pediatric anesthesia due to its rapid induction and recovery, nonpungent odor, and reduced airway irritation, which lowers the risk of bronchospasm and laryngospasm.

However, sevoflurane can cause side effects such as seizures, increased plasma inorganic fluoride levels, and a higher incidence of emergence delirium compared to halothane, highlighting the need for awareness among perianesthesia nurses.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Sevoflurane and emergence behavioral changes in pediatrics. Moos, DD.[2019]

Using a portable inhalational anesthetic circuit for sevoflurane induction outside the operating room (OR) in 100 children resulted in significantly faster anesthesia induction and awakening times compared to ketamine, with times of 28 seconds and 11.2 seconds respectively.

The sevoflurane group experienced less anxiety during induction (10% noncooperation) and showed better vital signs, including lower heart rates and higher oxygen saturation levels, indicating that this method is both safe and effective for pediatric patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Clinical effects of sevoflurane anesthesia induction with a portable inhalational anesthetic circuit in pediatric patients. Yu, M., Han, C., Zhou, Q., et al.[2020]

In a study involving 30 children aged 3-7 years, it was found that a lower concentration of sevoflurane is needed for laryngeal mask insertion (1.53%) compared to tracheal intubation (2.35%).

This suggests that sevoflurane is effective for both procedures, but using it for laryngeal mask insertion may be safer and require less anesthetic, which is beneficial in pediatric anesthesia.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[End-tidal sevoflurane concentrations for laryngeal mask airway insertion and tracheal intubation in children]. Grabowska-Gaweł, A.[2018]

In a study of 27,258 pediatric cases, the overall incidence of hypoxemia following inhalation induction of anesthesia was found to be 5.08%, with younger patients and those with higher ASA scores at greater risk.

The risk of hypoxemia significantly increases when the inspired oxygen concentration is below 60%, highlighting the importance of maintaining higher oxygen levels during anesthesia induction to ensure patient safety.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Incidence of post-induction hypoxemia in children and the effect of induction gas composition. Cumin, D., Baker, PA., Anderson, BJ.[2021]

Citations

1.

withpower.com

withpower.com/trial/phase-olfaction-disorders-5-2024-56ab4

Parosmia for Pediatric Anesthesia · Info for Participants

Research shows that sevoflurane, a component of the treatment, is effective for inhalation induction in children due to its non-irritating smell and quick ...

2.

ctv.veeva.com

ctv.veeva.com/study/chocolate-or-sevoflurane-use-of-parosmia-to-facilitate-more-cooperative-inhalation-inductions-in-ch

Chocolate or Sevoflurane: Use of Parosmia to Facilitate More ...

Parosmia is the distortion of smell perception which can utilized to the pediatric anesthesiologists advantage. It has been demonstrated that ...

3.

pmc.ncbi.nlm.nih.gov

pmc.ncbi.nlm.nih.gov/articles/PMC8676071/

High initial concentration versus low ... - PubMed Central - NIH

However, participant blinding during inhalation induction (performance bias) was inevitable. Incomplete outcome data (attrition bias): low, unclear, high risk.

4.

accessdata.fda.gov

accessdata.fda.gov/drugsatfda_docs/label/2025/020478s035lbl.pdf

ULTANE® (sevoflurane) volatile liquid for inhalation

ULTANE is indicated for induction and maintenance of general anesthesia in adult and pediatric patients for inpatient and outpatient surgery. ULTANE should ...

5.

frontiersin.org

frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2025.1548376/pdf

Safety profiles of sevoflurane in pediatric patients

Sevoflurane, a widely utilized inhalation anesthetic, occupies a significant role in neonatal and pediatric anesthesia due to its rapid onset ...

6.

frontiersin.org

frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2025.1548376/full

Safety profiles of sevoflurane in pediatric patients: a real- ...

Results: The FAERS database yielded 21,838,627 adverse event reports for children, with 474 involving sevoflurane as the primary suspect.

7.

pmc.ncbi.nlm.nih.gov

pmc.ncbi.nlm.nih.gov/articles/PMC11365654/

An analysis of the safety of Sevoflurane drugs

Sevoflurane is a volatile anesthetic that can tolerate inhalation induction and is widely used for inducing anesthesia due to its pleasant odor.

8.

journals.lww.com

journals.lww.com/md-journal/fulltext/2024/08300/an_analysis_of_the_safety_of_sevoflurane_drugs__a.15.aspx

An analysis of the safety of Sevoflurane drugs

For instance, after receiving Sevoflurane inhalation anesthesia, the child can cause laryngospasm and can be treated with intramuscular ...