Many of the books, articles, and blogs written about essential oils lack the scientifically validated information needed by healthcare professionals to confidently embrace this intervention for clinical use. There are some excellent exceptions, however. An extremely useful book for clinicians is by Robert Tisserand; Essential Oil Safety: A Guide for Health Care Professionals (25). One of the world’s leading authors and educators on essential oil therapy, Tisserand’s text helps translate complex and unfamiliar aromatherapy terminology into modern medical language. Another excellent reference book, Clinical Aromatherapy, Essential Oils in Practice (26), was written by Jane Buckle RN PhD, a nurse who has extensively researched EO therapy and developed a specialized massage technique for use in clinical settings.
While massage can be an extremely useful way to provide EO benefits, for nurses working in perioperative areas such as the operating room (OR) and the post anesthesia care unit (PACU), the most expedient and practical delivery method is by inhalation. TIEO lends itself particularly well to treating a common anesthesia side effect – postoperative nausea and vomiting (PONV). As patients emerge from anesthesia, they often feel queasy. Inhaled EOs can provide a rapid rescue treatment without causing further sedation or interacting with medications.
Since TIEO is not a drug, no order or pharmacy intervention is necessary. This allows for ready availability at the bedside, for quick administration when needed. The vapor can be easily inhaled from an appropriate device as often as necessary, even when the patient is drifting in and out of sleep.
TIEO has been designated as an independent nursing intervention in the Nursing Interventions Classification Manual (27). This evidence based handbook is used as the benchmark for establishing standards in hospital policy, third party reimbursement, nursing school curricula and Joint Commission reviews. The definition of an independent nursing intervention is an action that nurses are licensed to prescribe, perform, or delegate, based on their knowledge and skills, which do not require a physician’s order.
This designation can empower nurses to persist in the presence of potential barriers raised by fellow health care professionals, who may not yet understand complimentary medicine or be aware of the efficacy, and many safety benefits of EO therapy. With the awareness that TIEO is fully within their scope of practice, nurses can more confidently introduce it to their patients and coworkers in the clinical setting.
Safe Delivery Methods of TIEO
As noted earlier, common sense suggests that the safest concentration of EO vapor is the lowest ambient concentration that produces the desired effects. However, since EOs are different than drugs, there is no established recommended inhalation “dose”. The Food and Drug administration designated certain essential oils as “generally recognized as safe” (GRAS) when ingested orally, but no official “safe” ambient concentrations for essential oils have been established. This is primarily due to the outstanding safety record of EO vapor inhalation and the resultant lack of a need to establish airborne limits.
Dr. Buckle emphatically states, “Inhaled essential oils are unlikely to produce a toxic reaction. Hypothetically, a toxic reaction could occur if a person was con ned in a nonventilated room, the temperature was very high, and there was a constant diffusion of essential oil until the air was saturated. This would be more akin to suffocation than a reaction to the essential oil.” (26)
Likewise, Robert Tisserand says much the same: “ …from a safety standpoint it [inhalation] presents a very low level of risk to most people. Even in a relatively small closed room, and assuming 100% evaporation, the concentration of any essential oil or constituent is unlikely to reach a dangerous level, either from aromatherapy massage or from essential oil vaporization.” (25)
When one looks at the amount of vapor produced in a personal diffuser relative to these scenarios, it is clear that reasonable safety parameters are not only met, but also greatly exceeded when using an appropriate device designed for clinical TIEO therapy.
The biggest safety concern in the clinical environment is skin or mucous membrane irritation from undiluted essential oils. When used with a drowsy patient, it is imperative to prevent undiluted EOs from contacting the eyes, nose or mouth, where it could result in painful irritation. Containers specifically designed for the clinical environment allow the vapor to build up in a special chamber, prohibiting any skin contact. Techniques, such as using cotton balls, ribbons, or gauze soaked with EOs, placed near the patient’s face, are unable to afford the level of protection required and are not recommended.
Best practices dictate using specifically designed aromatic diffusers that have appropriate safety features, such as found with the product QueaseEASE™ by Soothing Scents. This product was designed by a certified registered nurse anesthetist (CRNA), for use with drowsy patients in the perioperative environment. Soothing Scents’ devices are configured to prevent undiluted EOs from contacting patients’ skin or mucosa, while still delivering sufficient vapor levels to quickly abate their symptoms. This type of delivery system can be confidently used in any clinical setting and sent home with the patient for safe use after discharge.
To use QueaseEASE™, at the first sign of nausea, simply peel back the top, and instruct patients to take several deep inhalations of the aroma whenever needed. If the patient is supine, it can be placed high on their chest, where the vapor can passively diffuse as they sleep.
Essential Oils for Treating Nausea
Nausea, especially in the postoperative patient, is caused by several factors that can occur simultaneously. A combination of anxiety, pain, dehydration, anesthetic medications, motion and decreased blood pressure, can activate several emetic pathways throughout the body. While antiemetic medications can reduce symptoms, they can be accompanied by undesirable side effects. Antiemetic drugs that are 5HT3 antagonists, such as ondansetron, are excellent at relieving vomiting but less effective in treating nausea. These medications work best when given as prophylaxis before exposure to emetic stimuli, and are less successful for treatment after nausea has occurred (28). For individuals with profound nausea, taking oral medications is difficult and can be pointless if it is immediately regurgitated.
These considerations make TIEO an excellent first line treatment for PONV in the perioperative setting. Investigational studies have shown that over 80% of patients needed no additional medication when TIEO was used at the first sign of queasiness in the PACU (29). For ambulatory surgery patients, TIEO can be useful for episodes that occur just prior to and after discharge, as patients can become queasy when they get dressed or during the car ride home. TIEO is one of the few treatment modalities available in these scenarios; with the IV removed at this stage, oral medication, if tolerated, will require the patient to delay discharge or be readmitted. With the incidence of post discharge nausea occurring in up to 30% of ambulatory patients (30), TIEO is an effective nursing intervention that can reduce facility costs, as well as patient distress.
The following are the most commonly encountered essential oils for treating nausea in the clinical setting. An important point to stress is that blending a combination of essential oils not only provides the unique benefits of each, it also helps prevent conditioned aversion.
Peppermint (Mentha Piperta), has a long history of relieving gastrointestinal distress, which is the reason for the traditional after dinner mint. Its main constituent, Menthol, is a terpene alcohol that exerts significant antispasmodic effects in the gastrointestinal (GI) system. One of the ways it works, is to reduce intestinal mobility by blocking calcium channel activity in smooth muscle. (31). Additionally, menthol promotes
gastric relaxation and decreases gastric tone, both through adrenergic pathways and by inhibiting the action of 5HT3 receptors (32).
Inhalation of Peppermint oil vapor is a rapid and practical rescue modality for relieving PONV (33). In addition to its antispasmodic benefits, it also most likely works on the same principle as the isopropyl alcohol prep pad, whereby the aromatic vapor quickly travels via the nose to the central nervous system, interrupting the nausea reflex cycle.
Another benefit of inhaled peppermint EO is the stimulatory effect it has on nociceptive receptors located inside the nostrils. When activated, these receptors elicit sensations such as the perception of increased airflow, coolness and freshness (34), all things that can help alleviate nausea.
This has proven to be particularly beneficial with patients undergoing cesarean. Spinal or regional anesthetics often cause nausea in women undergoing cesarean, which can be distressing for a number of reasons. During the procedure, women are supine, usually with their heads flat, forcing the gravid uterus upwards against the diaphragm, making it harder to breathe. Added to that are swollen nasal passages from 3rd trimester hormonal changes, and the decreased ability to feel the action of breathing due to the perceived numbing effect of regional anesthesia on the respiratory accessory muscles. Providing an essential oil blend containing peppermint not only relieves nausea, it also allows the sensation of greater airflow and deeper breaths, helping to alleviate or reduce the woman’s anxiety about inadequate breathing (35).
Spearmint (Mentha Spicata) is another mint with potent GI effects. Its primary constituent, Carvone, is a monoterpene ketone that has been found to exert significant relaxant and antispasmodic effects on gut smooth muscle as well as inhibit GI motility in animal studies (36). Additional research has shown that Carvone also has a potent antispasmodic effect on intestinal tissue, primarily via a calcium channel blocker mechanism (37).
Though not studied extensively on its own, recently spearmint combined with peppermint essential oil has been found to reduce chemotherapy induced nausea (38).
Ginger (Zingiber Officinale), composed primarily of sesquiterpene, (a terpene), and gingerol, (a phenolic compound), has been shown to possess significant anti emetic properties. Research suggests the mechanism of action may be its anti serotonin and 5HT3 receptor antagonism effects, both which figure prominently in nausea, especially PONV (39).
It has been studied in several formats; tea, tablets, essential oil vapor, candy and gum, resulting in some compelling data. When Ginger EO is inhaled on its own, it effectively decreases post op nausea (40), but also works very well in combination with other EOs such as peppermint, lavender and spearmint (41).
Animal and human studies show that it can enhance gastric emptying, and has shown efficacy in some, but not all, studies done on motion related nausea (42). A recent study found that women receiving highly emetic chemotherapy for breast cancer treatment had significantly less nausea and an increased ability to eat when they inhaled ginger essential oil (43). It appears to be useful and safe for pregnancy as well, as revealed by a recent Meta analysis (44), and it is used quite commonly as an anti-nausea agent for prevention or treatment of the morning sickness of pregnancy.
Lavender (Lavandula angustifolia) is one of the most commonly recognized essential oils in the world. Throughout history, it has been used in perfumes, as an antimicrobial, and as flavoring in food products. Today, modern medical interest is primarily focused on lavender’s potent anxiolytic and sedative effects. The main constituent of lavender is the monoterpene alcohol, linalool, which also provides its distinctive fragrance.
Because linalool occupies the same GABA receptor site as benzodiazepines, such as midazolam, it exhibits similar (though much milder), anxiolytic and sedative properties. EEG analysis shows that it induces an alpha brain wave pattern consistent with relaxation (45).
Multiple studies have consistently supported these findings in humans and animals, showing that lavender oil causes blood pressure, heart rate, and skin temperature changes that are consistent with decreases in autonomic nervous system arousal. (46,47).
Lavender can be useful for soothing anxiety, one of the causes of PONV. Patients often emerge from anesthesia in pain, and can become anxious, especially if they have a history of chronic pain, or failure of pain treatment after surgery. They may also become stressed about the possibility of retching, and the discomfort and potential surgical wound disruption that would cause.
Adding lavender to an antiemetic TIEO blend makes it a more complete and useful therapy throughout the perioperative phase. For example, in the OR, some patients have surgery under regional anesthetics, such as spinals, epidurals and other nerve blocks. This means they are awake, yet unable to feel or move parts of their body. This can lead to anxiety and nausea in the absence of concurrent sedation or antiemetic administration. Some patients may not be candidates for these medications due to coexisting diseases. TIEO can easily be administered to these patients during surgery, by simply placing an appropriate personal inhaler near their face to provide passive diffusion of the EO vapor. Even prior to going into the OR, patients can become stressed and nauseated from their IV insertion, pre-operative antibiotic administration, or fear. These patients can benefit from being able to self-administer and inhale TIEO whenever they determine the need, providing an important sense of control.
In contrast to antianxiety medications such as midazolam, nurses may choose to administer a lavender-containing TIEO without the necessity of obtaining an order, or being concerned about overly sedating the patient.
TIEO for Anxiety and Stress Relief
Wherever patient care is administered, there are sure to be patients who are stressed and anxious. Healthcare providers certainly need no explanation of why this occurs; they see the reasons in front of them everyday. What they do need is a compassionate and practical approach for safely and quickly addressing the patient’s stress and anxiety,
The wonderful aromas of essential oil therapy have long been credited with promoting relaxation. The understanding about how aromatic molecules target specific receptor sites to exert their calming effects is more recent. Fortunately, studies from around the world are being produced at a growing rate, enabling nurses and other healthcare professionals to continually add more EOs with calming benefits to their evidence based practice.
Lavender, previously described in the nausea section, can head up the list of essential oils found to be effective at relieving stress. The following EOs have also found to be effective in relieving anxiety, and can be used alone, or preferably in a blend, to synergistically combine their unique benefits. As always in a clinical setting, best practice dictates using a personal inhaler designed for patient safety.
Ylang Ylang (Cananga Odorata), pronounced “ee-lahng ee-lahng”, is an EO that has shown promise at relieving stress and promoting relaxation. It has a fresh, floral, intensely sweet smell and interestingly was the main ingredient in Macassar hair oil, used by men in Victorian times, and the reason for the advent of antimacassars (crocheted covers at the top of furniture to prevent oil stains) still found today on Victorian-era sofas and chairs.
Ylang Ylang’s main constituent is linalool, which helps explain why it displays biological markers consistent with autonomic nervous system depression, such as a mild decrease in blood pressure and heart rate (48). EEG brain wave studies show alpha wave patterns consistent with deep relaxation with skin application of Ylang Ylang (49), and when inhaled, it causes a feeling of relaxed “focus”, which research subjects described as “harmony”.
Bergamot (Citrus Birgamia) is an essential oil that is derived from the aromatic peel of the citrus fruit bergamot sour orange. It is the ingredient added to black tea that gives it the distinctive “Earl Grey ” flavor. The main components of this essential oil include the monoterpene linalool, and the cyclic terpene limonene.
It is beginning to attract attention in the clinical setting for its potent antianxiety properties. In a Chinese study, bergamot EO was combined with lavender and ylang ylang to test its effect on a group with essential hypertension. After inhaling this blend once per day, HR, BP and serum
cortisol levels were lower, and subjective reporting of stress and anxiety were also decreased when compared to placebo and control groups (50).
Another interesting study compared mice treated with Valium, mice given inhaled bergamot EO and a control group. The Valium and Bergamot group showed similar low stress behavior and both had lower levels of circulation stress hormones compared to the control group (51).
A study done on preoperative anxiety found that patients who inhaled bergamot EO were significantly less stressed in the preoperative holding area than those who did not (52).
Sweet Orange Oil (Citrus Sinensis) is predominantly composed of the terpene limonene. It has generated much interest for its anxiolytic effects and a few important studies have been done. In 2000, female patients waiting for a dental procedure were exposed to Sweet Orange EO. As compared to a control group, they had significantly less levels of anxiety (53). The same researcher combined Sweet Orange with Lavender and found both men and women had decreased anxiety, again, while waiting for a dental procedure (54). A Brazilian study compared physical markers such as heart rate and muscle tension, as well as tension and tranquility subjective scores and found a very strong anxiolytic effect with the group who inhaled sweet orange oil (55).
In animal models, the same effects have been achieved with interesting insights. It appears that the inhalational route in mice provided a deeper calming effect than previous studies with sweet orange EO using absorptive routes. These findings led researchers to speculate that odor molecules entering via the olfactory route more actively engage the area of the brain responsible for modulating threat processing (56).