Is nasal saline irrigation all it is cracked up to be?

Abstract

Objective

This review examines the literature regarding nasal saline irrigation in the management of sinonasal disease. We explore the various properties of nasal irrigation solutions and their effects on nasal symptoms.

Data Sources

English-language studies identified from MEDLINE and the Cochrane Central Register of Controlled Trials through December 2011.

Study Selections

Randomized, controlled trials (RCTs), prospective controlled and comparative studies, and observational studies reporting on the indications, efficacy, and safety of nasal saline irrigation.

Results

Nasal saline irrigation has often been used as both a solo and an adjunctive treatment in sinonasal diseases, including allergic rhinitis and chronic rhinosinusitis. Nasal saline irrigation has contributed to a reduction of inflammation as well as relief of nasal symptoms. Identifying the optimal technique is hampered by the fact that studies have employed various delivery devices and saline compositions, which subsequently have demonstrated different effects on mucus clearance, ciliary beat activity, and inflammatory mediators.

Conclusion

Overall, the data appear to demonstrate some small clinical benefit to nasal saline irrigation. Nasal saline irrigation is well tolerated, with minimal side effects. Further definitive studies are needed to optimize efficacy.

Introduction

Nasal saline irrigation (NSI) is common to both modern and traditional therapy regimens. Although NSI is frequently regarded as an adjunct to conventional treatment of sinonasal disease, it has demonstrated improvement in symptoms as well as reduction in the use of rescue medications such as systemic corticosteroids when used as an adjunct or as sole treatment. Although diverse, much of the literature regarding NSI is generally of low quality. In this review, we attempt to summarize the data that address the mechanism(s), efficacy, and safety of NSI in patients with sinonasal disease.

Sinonasal disease, which includes chronic rhinosinusitis, allergic rhinitis, and viral upper respiratory infections, is a significant cause of morbidity. Notably, chronic rhinosinusitis (CRS) is one of the most common chronic illnesses in Americans younger than 45 years of age, affecting nearly 13% of the US population.1 Based on the US National Health Interview survey, the number of non-institutionalized adults with diagnosed sinusitis in 2009 was 29.3 million, and the number of ambulatory care visits with a primary diagnosis of chronic sinusitis in 2007 was nearly 12.5 million,1 resulting in an annual treatment cost of sinusitis of close to $3 billion.2

Medical therapy has been the basis for treating CRS and other sinonasal diseases. Medications include short- and long-term antibiotic therapy, topical and systemic steroids, topical and oral decongestants, oral antihistamines, and mucolytics. Surgery is another therapeutic option; however, it is generally relegated to disease that is refractory to medical therapy.

The origins of nasal irrigation are believed to be from the ancient Hindu practice of Ayurveda, whose roots are traced to the Vedas. Neti (or Hatha Yogi) is an important part of the yogic system of body cleansing techniques.3 It is intended mainly for the cleaning of the air passageways in the head, and it has been used for thousands of years to alleviate sinus and allergy symptoms. The two main variants of neti are jala neti, using water poured into 1 nostril such that it leaves through the other nostril, and the more advanced sutra neti. In sutra neti, a length of wet string or thin surgical tubing is inserted through the nose and into the mouth. The end is then pulled out of the mouth and while holding both ends at once, the string is alternately pulled in and out of the nose. Both techniques are used to flush out the nasal cavities by using gravity to draw the flow of saline water through nasal passages.3

Nasal saline irrigation has gained popularity amongst consumers as exemplified by media coverage on National Public Radio.[4], [5] Independent market data provided by A.C. Nielsen demonstrated that sales of saline irrigation products have doubled annually for the last few years.6 Apparently NSI has made a recent comeback, likely because it is a relatively inexpensive and easily administered therapy.

The exact mechanism(s) of action of NSI are not clearly understood. The mucus lining of the nasal cavity constitutes one of the body's first lines of defense against potential pathogenic organisms,7 and these organisms may subsequently become entrapped in the mucus. NSI may enhance the movement of mucus toward the nasopharynx, directly clean the nasal mucosa,8 and aid in thinning nasal secretions.[9], [10] It may promote clearance of inflammatory mediators such as histamine and prostaglandins,11 prevent secondary infection, and promote mucosal healing.[9], [10] NSI is also thought to play an important role in the postoperative period, because it reduces the risk of adhesions and promotes ostiomeatal patency.12 Finally, chronic sinonasal disease leads to a decline in mucociliary clearance (MCC), and this is presumed to be a result of osmotic changes in the mucus layer or reduction in the ciliary beat frequency (CBF).[9], [12] For these reasons, the physiological changes that theoretically occur with use of NSI make it an attractive therapy for many sinonasal conditions.

NSI is recommended for a variety of sinonasal conditions, including allergic rhinitis (AR), atrophic rhinitis, rhinitis of pregnancy, viral upper respiratory tract infections (URTIs), CRS, acute rhinosinusitis, sinonasal sarcoidosis, Wegener's granulomatosis, and as a postoperative adjunct after functional endoscopic sinus surgery (FESS).10 Although there are very few absolute contraindications for NSI, patients with incompletely healed facial trauma, those suffering from conditions associated with an increased risk for aspiration (such as neuromuscular disorders), or those who cannot perform the procedure should avoid this modality.13

Few comparative, prospective and reproducible studies consistently demonstrate NSI's efficacy. We summarize the literature regarding NSI stratified by sinonasal disease as follows:

Rabago et al14 investigated the benefit of NSI in 76 adults with chronic sinusitis or recurrent acute sinusitis. In this randomized controlled trial (RCT), 52 subjects received 150 mL per nostril daily of 2.0% buffered saline (with baking soda) delivered via SinuCleanse Nasal Cup (Med-Systems, Inc., Madison, Wisconsin) for 6 months. Twenty-four subjects as part of the control group received no topical therapy. The primary outcomes were quality of life (QOL) scores from 2 validated questionnaires: the general health assessment Medical Outcomes Survey (MOS) Short Form12 (SF12)15 and the Rhinosinusitis Disability Index (RSDI),16 a disease-specific instrument assessing QOL in emotional, functional, and physical domains. The investigators also measured overall sinus symptoms severity with a Single-Item Symptom Severity Assessment (SIA). The SIA measures global sinus symptom severity, with higher SIA scores indicating increased severity.14 Antibiotic use, compliance, and adverse events were secondary outcomes. At 6 months, RSDI improvement was 24.7% (−14.4, P < .05), and SIA improvement was 41% (−1.6; P < .05) in active treatment compared with the control group. The SF-12 did not show a statistically significant improvement. Subjects randomized to active therapy also reported fewer 2-week periods with sinus-related symptoms (P < .05) and used fewer antibiotics (p < .05).14 Notably, in a 12-month follow-up to this study, the investigators found sustained improvement in both the RSDI (P < .001) and SIA scores (P = .01).17

In contrast, Heatley et al18 compared the efficacy of NSI with that of “control” treatment in an RCT and found equivalence between these modalities. In this crossover study, 150 adult subjects with CRS were randomized to receive 2.7% hypertonic NSI via a bulb syringe, 2.7% hypertonic NSI via nasal irrigation pot or to receive reflexology massage as a “placebo” for 2 weeks each. QOL scores from two validated surveys—the Medical Outcomes Survey Short Form 36-Item Health Survey (SF36)19 and the 31-Item Rhinosinusitis Outcomes Measures (RSOM31)20—were used as primary endpoints. Significant but equivalent improvement in RSOMI31 score occurred after 2 weeks of intervention in all 3 groups (P < .01), and 35% of all subjects using irrigation or reflexology reported decreased use of sinus medications, with no measurable difference between the 3 groups.18

Both strengths and limitations are worth noting in these studies. The attrition rate was significant, with 9% (7 of 76) of subjects in the Rabago14 and 15% (22 of 150) in the Heatley study18 failing to complete the study. Both studies used validated questionnaires; however, blinding was not addressed in the Heatley trial. The Rabago study examined outcomes via a prolonged 6-month study, whereas Heatley's study was limited to only 2 weeks of treatment.[14], [18]

In a Cochrane meta-analysis by Harvey et al,21 the authors found that NSI was beneficial in the treatment of CRS and could be included as a sole treatment or treatment adjunct for CRS. In this meta-analysis, 8 trials were identified that satisfied the inclusion criteria. Three studies compared topical saline with no treatment, 1 against placebo, 1 as an adjunct to, and 1 compared NSI with intranasal steroids. Furthermore, 2 studies compared different hypertonic solutions versus isotonic saline. From these studies, NSI was concluded to be beneficial in the treatment of the symptoms of CRS when used as the sole modality of treatment. Evidence also exists in favor of saline as a treatment adjunct. However, NSI was not found to be as effective as an intranasal steroid.21

Garavellos et al22 investigated the efficacy of NSI using hypertonic saline as an adjunctive treatment in the prevention of seasonal allergic rhinitis (SAR) related symptoms in children. In this RCT, 20 children with SAR to Parietaria23 were randomized to receive daily NSI with 3% hypertonic saline delivered by syringe with a volume of 2.5 mL to each nostril three times per day during the season (6 weeks) or no topical solution. Subjects were allowed to use rescue antihistamines. The main outcome was the “mean daily rhinitis score,” which was based on the following symptoms: (1) nasal itching; (2) rhinorrhea; (3) nasal obstruction; and (4) wheezing. Intensity of each of these 4 symptoms was rated on a scale of 0 to 4. In subjects allocated to NSI, the “mean daily rhinitis score” significantly improved in the 3rd, 4th, and 5th weeks of therapy (P < .05) compared with the control group. Furthermore, a significant decrease occurred in oral antihistamine rescue (P < .05) during the 3rd, 4th, and 6th weeks of treatment. No patients were lost to follow-up in this study.22

In a later study, Garavello et al24 evaluated the effect of topical 3% hypertonic saline administered via a nasal atomizer spray in children with rhinoconjunctivitis symptoms. In this RCT, 44 children (<16 years of age) with SAR were randomized to receive hypertonic saline or no topical treatment for 7 weeks. Antihistamine use was permitted for rescue and its use recorded. The main outcome was the “mean weekly rhinoconjunctivitis score” based on the presence of 4 symptoms: (1) nasal discharge; (2) nasal obstruction; (3) ocular reddening; and (4) ocular pruritis. The degree of severity of each symptom was recorded on a scale of 0 to 3 [0 = none; 1 = mild; 2 = moderate; 3 = severe]. A total score representing the sum of the scores of these 4 symptoms was then used to calculate a mean daily rhinitis score per patient per week. The mean weekly rhinoconjunctivitis score in the active group was numerically improved throughout the entire pollen season, and this difference became statistically significant in the 6th and 7th week (P < .05). A statistically significant reduction in intake of oral antihistamine rescue also was found in 5 of the 7 weeks (P < .05). Four patients (2 from each group) did not complete the study.24

Although both studies described adequate randomization and concealment procedures, neither study described the blinding process, nor did either rely on a validated questionnaire or objective outcomes. One also must question whether 3 times per day use of NSI would be a reasonable expectation in a pediatric population.

In a two-phase, multicenter, parallel group, open, and randomized comparison trial,25 390 children, ages 6 through 10, with URTIs were randomized to receive either standard medications (antipyretics, nasal decongestants, mucolytics, and ± systemic antibiotics) plus isotonic NSI (Atlantic Ocean seawater, Physiomer; Goemar Laboratoire de la Mer, Saint Malo, France) via either medium jet flow (9 mL of liquid each nostril) or fine spray (3 mL per nostril) or standard medications alone. They were followed for 3 weeks during the “acute illness phase” (continuing to use the assigned treatment regimen 6 times per day) and then for an additional 9 weeks during the prevention phase (using the assigned treatment regimen 3 times per day). The primary efficacy end-points were nasal symptom resolution during an acute illness (visits 1 and 2) and during the preventive phase (visits 3 and 4), the reappearance of symptoms, additional medication usage, complications, days of missed school, and reported days of illness. Composite ‘rhinologic scores’ were measured on a 4-point numeric scale (‘1’ indicated no symptoms, and ‘4’ indicated severe symptoms). The parameters assessed included nasal secretion and its type, nasal obstruction, sore throat, cough and expectoration, sneezing, itching, and loss of senses of smell and taste. In both phases, the NSI delivery groups demonstrated equally and statistically significant improvement in nasal secretions and obstruction compared with control (mean scores versus non-saline group during treatment phase, 1.79 vs 2.10 and 1.25 vs 1.58, respectively, P < .05 for both). During the “prevention phase,” subjects stratified to the saline group showed significant improvement in symptoms of sore throat, cough, nasal obstruction and secretion (P < .05 for all).25

In contrast, Adam et al26 conducted a three-arm randomized controlled trial, enrolling 143 adults with viral URTIs randomized to receive hypertonic 2% buffered spray NSI, normal saline (0.9%) NSI, or ‘no treatment.' The main outcomes were the nasal symptom score (NSS) on day 3 and time to symptom resolution. The NSS consisted of the sum of scores for nasal congestion, rhinorrhea, and headache, with each score rated on a 4-point severity score (0, no symptoms; 1, mild symptoms; 2, moderate symptoms; and 3, severe symptoms). The day 3 mean nasal symptom score was 3.8 (95% CI, 3.0–4.5) for the group randomized to hypertonic saline, 3.7 (95% CI, 2.9–4.5) for the normal saline group, and 4.1 (95% CI, 3.5–4.7) for the no treatment group. Ultimately, no significant differences were found with respect to the primary outcome measures when hypertonic saline was compared with normal saline or no-treatment groups, and neither active treatment resulted in a diminution of the duration or severity of nasal symptoms compared with control.26

In a Cochrane meta-analysis, Kassel et al27 evaluated the efficacy of NSI in treating the symptoms of acute URTIs in children and adults. Three RCTs (618 participants) comparing topical nasal saline treatment with other interventions in adults and children with clinically diagnosed acute URTIs were included. Most outcomes examined demonstrated no difference between nasal saline treatment and control. There was limited evidence of benefit with NSI in adults. One study showed a mean difference of 0.3 day (out of 8 days) for symptom resolution, but this was not significant. The authors conclude that the included trials were too small and had too high a risk of bias to be confident about the possible benefits of NSI in acute URTIs.

Section snippets

Discussion

There are notable limitations in the previous studies. These studies generally involved only a small number of subjects, most examined subjects with CRS, subjects were allowed to take other medications (including oral antihistamines and antibiotics), follow-up was limited, attrition was significant, and blinding was often not addressed. Significant heterogeneity existed between the study designs, including duration of treatment, outcome measures, as well as variables regarding NSI itself, such

Conclusion

NSI is a frequent component of treatment of sinonasal disease and is usually well tolerated. Overall the data demonstrate some small clinical benefit. Surprisingly, despite the fact that NSI has been used since ancient yoga times, data supporting its use currently are nominal. Given the disparity in various pathological conditions, future studies should focus on specific phenotypes of sinonasal diseases. Present data also reinforce the importance of well-designed studies with robust subject

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Disclosures: Authors have nothing to disclose.