Effects of inhaled hypertonic (7%) saline on lung function test in preschool children with cystic fibrosis: results of a crossover, randomized clinical trial

Nebulised hypertonic saline for cystic fibrosis

BACKGROUND

Hypertonic saline enhances mucociliary clearance and may lessen the destructive inflammatory process in the airways. This is an update of a previously published review.

OBJECTIVES

To investigate efficacy and tolerability of nebulised hypertonic saline treatment in people with cystic fibrosis (CF) compared to placebo or other treatments that enhance mucociliary clearance.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Cystic Fibrosis Trials Register, comprising references identified from comprehensive electronic database searches, handsearches of relevant journals and abstract books of conference proceedings. We also searched ongoing trials databases. Most recent search: 25 April 2022.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials assessing hypertonic saline compared to placebo or other mucolytic therapy, for any duration or dose regimen in people with CF (any age or disease severity).

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed all identified trials and data, and assessed trial quality. We assessed the certainty of the evidence using GRADE. For cross-over trials we stipulated a one-week washout period. We planned to use results from a paired analysis in the review, but this was only possible in one trial. For other cross-over trials, we chose to treat the trials as if they were parallel.

MAIN RESULTS

We included 24 trials (1318 participants, aged one month to 56 years); we excluded 29 trials, two trials are ongoing and six are awaiting classification. We judged 15 of the 24 included trials to have a high risk of bias due to participants' ability to discern the taste of the solutions. Hypertonic saline 3% to 7% versus placebo (stable disease) We are uncertain whether the regular use of nebulised hypertonic saline in stable lung disease leads to an improvement in forced expiratory volume in one second (FEV1) % predicted at four weeks, (mean difference (MD) 3.30%, 95% confidence interval (CI) 0.71 to 5.89; 4 trials, 246 participants; very low-certainty evidence). In preschool children we found no difference in lung clearance index (LCI) at four weeks, but a small improvement after 48 weeks of treatment with hypertonic saline compared to isotonic saline (MD -0.60, 95% CI -1.00 to -0.19; 2 trials, 192 participants). We are also uncertain whether hypertonic saline made a difference to mucociliary clearance, pulmonary exacerbations or adverse events compared to placebo. Hypertonic saline versus control (acute exacerbation) Two trials compared hypertonic saline to control, but only one provided data. There may be little or no difference in lung function measured by FEV1 % predicted after hypertonic saline compared to isotonic saline (MD 5.10%, 95% CI -14.67 to 24.87; 1 trial, 130 participants). Neither trial reported any deaths or measures of sputum clearance. There were no serious adverse events. Hypertonic saline versus rhDNase Three trials compared a similar dose of hypertonic saline to recombinant deoxyribonuclease (rhDNase); two trials (61 participants) provided data for inclusion in the review. We are uncertain whether there was an effect of hypertonic saline on FEV1 % predicted after three weeks (MD 1.60%, 95% CI -7.96 to 11.16; 1 trial, 14 participants; very low-certainty evidence). At three months, rhDNase may lead to a greater increase in FEV1 % predicted than hypertonic saline (5 mL twice daily) at 12 weeks in participants with moderate to severe lung disease (MD 8.00%, 95% CI 2.00 to 14.00; low-certainty evidence). We are uncertain whether adverse events differed between the two treatments. No deaths were reported. Hypertonic saline versus amiloride One trial (12 participants) compared hypertonic saline to amiloride but did not report on most of our outcomes. The trial found that there was no difference between treatments in measures of sputum clearance (very low-certainty evidence). Hypertonic saline compared with sodium-2-mercaptoethane sulphonate (Mistabron®) One trial (29 participants) compared hypertonic saline to sodium-2-mercaptoethane sulphonate. The trial did not measure our primary outcomes. There was no difference between treatments in any measures of sputum clearance, courses of antibiotics or adverse events (very low-certainty evidence). Hypertonic saline versus mannitol One trial (12 participants) compared hypertonic saline to mannitol, but did not report lung function at relevant time points for this review; there were no differences in sputum clearance, but mannitol was reported to be more 'irritating' (very low-certainty evidence). Hypertonic saline versus xylitol Two trials compared hypertonic saline to xylitol, but we are uncertain whether there is any difference in FEV1 % predicted or median time to exacerbation between groups (very low-certainty evidence). No other outcomes were reported in the review. Hypertonic saline 7% versus hypertonic saline 3% We are uncertain whether there was an improvement in FEV1 % predicted after treatment with 7% hypertonic saline compared with 3% (very low-certainty evidence).

AUTHORS' CONCLUSIONS

We are very uncertain if regular use of nebulised hypertonic saline by adults and children over the age of 12 years with CF results in an improvement in lung function after four weeks (three trials; very low-certainty evidence); there was no difference seen at 48 weeks (one trial; low-certainty evidence). Hypertonic saline improved LCI modestly in children under the age of six years. Evidence from one small cross-over trial in children indicates that rhDNase may lead to better lung function than hypertonic saline at three months; qualifying this, we highlight that while the study did demonstrate that the improvement in FEV1 was greater with daily rhDNase, there were no differences seen in any of the secondary outcomes. Hypertonic saline does appear to be an effective adjunct to physiotherapy during acute exacerbations of lung disease in adults. However, for the outcomes assessed, the certainty of the evidence ranged from very low to low at best, according to the GRADE criteria. The role of hypertonic saline in conjunction with cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy now needs to be considered, and future research needs to focus on this aspect.

Efficacy of hypertonic saline versus isotonic saline among children with cystic fibrosis: A systematic review and meta-analysis

Background

Inhaled hypertonic saline (HS) reduces pulmonary exacerbations in patients with cystic fibrosis (CF) aged 6 or more years. However, the effectiveness of HS in improving clinical outcomes in younger children aged 6 or less years is not established. This study examines the efficacy of HS in younger CF patients.

Methods

Searches were conducted across three databases (Medline, Cochrane Central and EMBASE) from inception through July 2022. Randomized controlled trials assessing the impact of HS in younger CF patients were included. Trials involving only patients greater than 6 years or control group other than isotonic saline (IS) were excluded. Outcomes measured included lung clearance index (LCI), cystic fibrosis questionnaire (CFQ-R) score, spirometry measures, oxygen saturation, respiratory rate, height and weight. Outcomes were reported as mean differences (MDs) with 95% confidence intervals.

Results

Seven studies (n = 390 patients) were included in this review. HS significantly reduced the LCI (MD: -0.67; 95%CI, -1.05 to 0.29, P = 0.0006) compared to IS. In addition, HS was associated with significant improvements in height (MD: 2.23; 95%CI, -0.00 to 4.46, P = 0.05) and CFQ-R (MD: 4.30; 95%CI, 0.65-7.95, P = 0.02), but not in oxygen saturation (MD: -0.15; 95%CI, -0.54 to 0.25, P = 0.47), respiratory rate (MD: -0.21; 95%CI, -2.19 to 1.77, P = 0.83) or weight (MD: 0.70; 95%CI, -0.47 to 1.87, P = 0.24). Furthermore, HS did not significantly improve spirometry measures, including FEV₁ (MD: -0.11; 95%CI, -0.21 to 0.43, P = 0.51) and forced vital capacity (MD: 0.27; 95%CI, -0.49 to 1.04, P = 0.48), but significantly improved FEF_25-75 (MD: 0.12; 95% CI, 0.05-0.20; P = 0.002).

Discussion

Treatment with HS in younger children with CF improves lung clearance, symptoms and quality of life. FEF_25-75 may prove a more sensitive measure for assessing intervention related improvements in pediatric CF trials.

Conclusion

The findings support HS as a therapeutic method in CF-affected children.

Recent advances in the early treatment of cystic fibrosis: Bridging the gap to highly effective modulator therapy

Highly effective modulator therapy (HEMT) for cystic fibrosis (CF) has been touted as one of the greatest advances to date in CF care. As these therapies are now available for many older children and adults with CF, marked improvement of their nutritional status, pulmonary and gastrointestinal symptoms has been observed. However, most infants and younger children are not current candidates for HEMT due to age and/or cystic fibrosis transmembrane conductance regulator (CFTR) mutation. For these young children, it is essential to provide rigorous monitoring and care to avoid potential disease sequelae while awaiting HEMT availability. The following article highlights recent advances in the care of infants and young children with CF with regard to surveillance and treatment of nutritional, pulmonary, and gastrointestinal disorders. Recent clinical trials in this population are also reviewed.

Children With Asthma Have Impaired Innate Immunity and Increased Numbers of Type 2 Innate Lymphoid Cells Compared With Healthy Controls

Background

Asthma is the most frequent cause of hospitalisation among children; however, little is known regarding the effects of asthma on immune responses in children.

Objective

The present study aimed to evaluate cytokine responses of peripheral blood mononuclear cells (PBMCs), PBMC composition and lung function in children with and without asthma.

Methods

Using a case-control design, we compared 48 children with asthma aged 3-11 years with 14 age-matched healthy controls. PBMC composition and cytokine production including interferon (IFN)-γ, interleukin (IL)-1β, IL-5 and lL-6 following stimulation with rhinovirus-1B (RV1B), house dust mite (HDM) and lipopolysaccharide (LPS) were measured. Lung function was assessed using impulse oscillometry and nitrogen multiple breath washout.

Results

The frequency of group 2 innate lymphoid cells were significantly higher in asthmatics and PBMCs from asthmatics had deficient IFN-γ production in response to both RV1B and LPS compared with controls (P<0.01). RV1B-induced IL-1β response and HDM-stimulated IL-5 production was higher in asthmatics than controls (P<0.05). In contrast, IL-1β and IL-6 were significantly reduced in response to HDM and LPS in asthmatics compared to controls (P<0.05). Children with asthma also had reduced pulmonary function, indicated by lower respiratory reactance as well as higher area of-reactance and lung clearance index values compared with controls (P<0.05).

Conclusion

Our study indicates that children with asthma have a reduced lung function in concert with impaired immune responses and altered immune cell subsets. Improving our understanding of immune responses to viral and bacterial infection in childhood asthma can help to tailor management of the disease.

[Application of a multiple linear regression model of FEV1 in pulmonary function test]

OBJECTIVE

To construct a multiple linear regression model of forced expiratory volume in 1 second (FEV1) for estimating FEV1 in special populations unable to receive or uncooperative in pulmonary ventilation function tests.

METHODS

The multiple linear regression model of FEV1 was constructed based on the data of 813 individuals undergoing pulmonary function tests in First Affiliated Hospital of Zhejiang Chinese Medical University between September, 2017 and September, 2019, and was validated using the data of another 94 individuals from the same hospital between January and July, 2020. FEV1 of the individuals was measured by pulmonary ventilation function test, and respiratory resistance (Rrs) was measured using forced oscillation technique (FOT). Pearson correlation analysis was used to assess the correlation between the factors, and the model equation was established by multiple stepwise regression analysis. The calculated FEV1 based on the model was compared with the measured FEV1 among both the individuals included for modeling and validation.

RESULTS

FEV1 was not significantly correlated with BMI (r=-0.026, P=0.457), poorly correlated with body mass (r=0.382, P=0.000), positively correlated with height (r=0.723, P=0.000), and negatively correlated with Rrs (r=-0.503, P=0.000) with an obvious gender differences (t=18.517, P=0.000). FEV1 was positively correlated with age among individuals below 25 years of age (r=0.578, P=0.000) and was negatively correlated with age among those beyond or at the age of 25 (r=-0.589, P=0.000). For individuals beyond or at the age of 25 years, the variables of height, gender, age and Rrs were included in the model, and the calculated FEV1 did not differ significantly from the measured values in either the modeling sample (n=751; t=1.293, P=0.196) or the verification sample (n=83;t=-1.736, P=0.086), and the two values were well correlated in the verification sample (r=0.891, P=0.000). For individuals below 25 years, only height was included in the model, and the calculated FEV1 and the measured values showed no significant difference in the modeling sample (n=62; t=-0.009, P=0.993) or the verification sample (n=11; t=-0.635, P=0.540) with a good correlation in the verification sample (r=0.795, P=0.003).

CONCLUSIONS

The multiple linear regression model for calculating FEV1 constructed in this study is suitable for clinical application.

Therapeutic effect of nebulized hypertonic saline for muco-obstructive lung diseases: a systematic review and meta-analysis with trial sequential analysis

Overproduction of mucus and impaired clearance play important roles in the pathogenesis of muco-obstructive lung diseases (MOLDs). This study aims to evaluate the therapeutic effect and safety of nebulized hypertonic saline (HS) on MOLDs. Five electronic databases including PubMed, Excerpt Medica Database (EMBASE), Cochrane Central Register of Controlled Trials, ClinicalTrials.gov and International Standard Randomized Controlled Trial Number Register were searched until June 2019. Randomized controlled trials or randomized controlled crossover trials which investigated the therapeutic effect of HS versus non-HS for MOLDs were included. Twenty-one studies met the eligibility criteria. For cystic fibrosis (CF), although the forced expiratory volume in the first second and forced vital capacity did not improve significantly (mean difference (MD) -0.48, 95% CI -3.72 to 2.76), (MD 1.85, 95% CI -4.31 to 8.01), respectively), the clearance capability of lung and quality of life (QOL) improved significantly in the HS group ((standard mean difference 0.44, 95% CI 0.02 to 0.87), (MD -0.64, 95% CI -)1.14, to 0.13), respectively). However, the results of trial sequential analysis showed the evidence needed more researches to support. The effect of nebulized HS on non-CF bronchiectasis, chronic obstructive pulmonary disease, and primary ciliary dyskinesia also need more evidence to conclude, since current studies are limited and results are inconsistent. Most adverse events of nebulized HS were mild and transient. In summary, the current available evidence suggests that nebulized HS may increase the QOL in CF, but there was no significant improvement in lung function. However, it is not possible to draw firm conclusions for other MOLDs due to limited data.

Timing of hypertonic saline inhalation for cystic fibrosis

BACKGROUND

Inhalation of hypertonic saline improves sputum rheology, accelerates mucociliary clearance and improves clinical outcomes of people with cystic fibrosis. This is an update of a previously published Cochrane Review.

OBJECTIVES

To determine whether the timing of hypertonic saline inhalation (in relation to airway clearance techniques or in relation to time of day) has an impact on its clinical efficacy in people with cystic fibrosis.

SEARCH METHODS

We identified relevant randomised and quasi-randomised controlled trials from the Cochrane Cystic Fibrosis Trials Register, the Physiotherapy Evidence Database (PEDro), and international cystic fibrosis conference proceedings. Date of the last search of the Cochrane Cystic Fibrosis and Genetic Disorders Group's Cystic Fibrosis Trials Register: 28 February 2019.

SELECTION CRITERIA

Any trial of hypertonic saline in people with cystic fibrosis where timing of inhalation was the randomised element in the study protocol with either: inhalation up to six hours before airway clearance techniques compared to inhalation during airway clearance techniques compared to inhalation up to six hours after airway clearance techniques; or morning compared to evening inhalation with any definition provided by the author.

DATA COLLECTION AND ANALYSIS

Both authors independently assessed the trials identified by the search for potential inclusion in the review. The certainty of the evidence was assessed using GRADE.

MAIN RESULTS

The searches identified 104 trial reports which represented 51 trials, of which three cross-over trials (providing data on 77 participants) met our inclusion criteria. We present three comparisons: inhalation before versus during airway clearance techniques; inhalation before versus after airway clearance techniques; and inhalation during versus after airway clearance techniques. One trial (50 participants), given its three-arm design, was eligible for all three comparisons. No trials compared morning versus evening inhalation of hypertonic saline. The evidence from the three trials was judged to be of low quality downgraded for limitations (high risk of bias due to blinding) and indirectness (all participants are adults, and therefore not applicable to children). Intervention periods ranged from one treatment to three treatments in one day. There were no clinically important differences between the timing regimens of inhaling hypertonic saline before, during or after airway clearance techniques in the mean amount of improvement in lung function or symptom scores (77 participants), with the between-group comparisons being non-significant (low-certainty evidence). While there may be little or no difference in the rating of satisfaction when hypertonic saline was inhaled before versus during the airway clearance techniques (64 participants) (with the 95% confidence interval including the possibility of both a higher and lower rating of satisfaction), satisfaction may be lower on a 100-mm scale when inhaled after the airway clearance techniques compared to before: mean difference (MD) 20.38 mm (95% confidence interval (CI) 12.10 to 28.66) and when compared to during the techniques, MD 14.80 mm (95% CI 5.70 to 23.90). Perceived effectiveness showed similar results: little or no difference for inhalation before versus during airway clearance techniques (64 participants); may be lower when inhaled after the airway clearance techniques compared to before, MD 10.62 (95% CI 2.54 to 18.70); and also when compared to during the techniques, MD 15.60 (95% CI 7.55 to 23.65). There were no quality of life or adverse events reported in any of the trials.

AUTHORS' CONCLUSIONS

Timing of hypertonic saline inhalation makes little or no difference to lung function (low-certainty evidence). However, inhaling hypertonic saline before or during airway clearance techniques may maximise perceived efficacy and satisfaction. The long-term efficacy of hypertonic saline has only been established for twice-daily inhalations; however, if only one dose per day is tolerated, the time of day at which it is inhaled could be based on convenience or tolerability until evidence comparing these regimens is available. The identified trials were all of very short intervention periods, so longer-term research could be conducted to establish the effects arising from regular use, which would incorporate the influence of changes in adherence with long-term use, as well as generating data on any adverse effects that occur with long-term use.

Particle coating alters mucociliary transit in excised rat trachea: A synchrotron X-ray imaging study

We have previously developed non-invasive in vivo mucociliary transport (MCT) monitoring methods using synchrotron phase contrast X-ray imaging (PCXI) to evaluate potential therapies for cystic fibrosis (CF). However, previous in vivo measurements of MCT velocity using this method were lower than those from alternate methods. We hypothesise this was due to the surface chemistry of the uncoated particles. We investigated the effect of particle surface coating on MCT marker performance by measuring the velocity of uncoated, positively-charged (aminated; NH₂), and negatively-charged (carboxylated; COOH) particles. The effect of aerosolised hypertonic saline (HS) was also investigated, as previous in vivo measurements showed HS significantly increased MCT rate. PCXI experiments were performed using an ex vivo rat tracheal imaging setup. Prior to aerosol delivery there was little movement of the uncoated particles, whilst the NH₂ and COOH particles moved with MCT rates similar to those previously reported. After application of HS the uncoated and COOH particle velocity increased and NH₂ decreased. This experiment validated the use of COOH particles as MCT marker particles over the uncoated and NH₂ coated particles. Our results suggest that future experiments measuring MCT using synchrotron PCXI should use COOH coated marker particles for more accurate MCT quantification.

Nebulised hypertonic saline for cystic fibrosis

BACKGROUND

Impaired mucociliary clearance characterises lung disease in cystic fibrosis (CF). Hypertonic saline enhances mucociliary clearance and may lessen the destructive inflammatory process in the airways. This is an update of a previously published review.

OBJECTIVES

To investigate efficacy and tolerability of treatment with nebulised hypertonic saline on people with CF compared to placebo and or other treatments that enhance mucociliary clearance.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Cystic Fibrosis Trials Register, comprising references identified from comprehensive electronic database searches, handsearches of relevant journals and abstract books of conference proceedings. We also searched ongoing trials databases.Date of most recent searches: 08 August 2018.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials assessing hypertonic saline compared to placebo or other mucolytic therapy, for any duration or dose regimen in people with CF (any age or disease severity).

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed all identified trials and data, and assessed trial quality. The quality of the evidence was assessed using GRADE.

MAIN RESULTS

A total of 17 trials (966 participants, aged 4 months to 63 years) were included; 19 trials were excluded, three trials are ongoing and 16 are awaiting classification. We judged 14 of the 17 included trials to have a high risk of bias due to participants ability to discern the taste of the solutions.Hypertonic saline 3% to 7% versus placeboAt four weeks, we found very low-quality evidence from three placebo-controlled trials (n = 225) that hypertonic saline (3% to 7%, 10 mL twice-daily) increased the mean change from baseline of the forced expiratory volume at one second (FEV1) (% predicted) by 3.44% (95% confidence interval (CI) 0.67 to 6.21), but there was no difference between groups in lung clearance index in one small trial (n = 10). By 48 weeks the effect was slightly smaller in one trial (n = 134), 2.31% (95% CI -2.72 to 7.34) (low-quality evidence). No deaths occurred in the trials. Two trials reporting data on exacerbations were not combined as the age difference between the participants in the trials was too great. One trial (162 adults) found 0.5 fewer exacerbations requiring antibiotics per person in the hypertonic saline group; the second trial (243 children, average age of two years) found no difference between groups (low-quality evidence). There was insufficient evidence reported across the trials to determine the rate of different adverse events such as cough, chest tightness, tonsillitis and vomiting (very low-quality evidence). Four trials (n = 80) found very low-quality evidence that sputum clearance was better with hypertonic saline.A further trial was performed in adults with an acute exacerbation of lung disease (n = 132). The effects of hypertonic saline on short-term lung function, 5.10% higher (14.67% lower to 24.87% higher) and the time to the subsequent exacerbation post-discharge, hazard ratio 0.86 (95% CI 0.57 to 1.30) are uncertain (low-quality evidence). No deaths were reported. Cough and wheeze were reported but no serious adverse events (very low-quality evidence).Hypertonic saline versus mucus mobilising treatments Three trials compared a similar dose of hypertonic saline to recombinant deoxyribonuclease (rhDNase); two (61 participants) provided data for inclusion in the review. There was insufficient evidence from one three-week trial (14 participants) to determine the effects of hypertonic saline on FEV1 % predicted, mean difference (MD) 1.60% (95% CI -7.96 to 11.16) (very low-quality evidence). In the second trial, rhDNase led to a greater increase in FEV1 % predicted than hypertonic saline (5 mL twice daily) at 12 weeks in participants with moderate to severe lung disease, MD 8.00% (95% CI 2.00 to 14.00) (low-quality evidence). One cross-over trial (47 participants) reported 15 exacerbations during treatment with hypertonic saline and 18 exacerbations in the rhDNase group (low-quality evidence). Increased cough was reported in 13 participants using hypertonic saline and 17 on daily rhDNase in one cross-over trial of 47 people (low-quality evidence). There was insufficient evidence to assess rates of other adverse events reported. No deaths were reported.One trial (12 participants) compared hypertonic saline to amiloride and one (29 participants) to sodium-2-mercaptoethane sulphonate. Neither trial found a difference between treatments in any measures of sputum clearance; additionally the comparison of hypertonic saline and sodium-2-mercaptoethane sulphonate reported no differences in courses of antibiotics or adverse events (very low-quality evidence).One trial (12 participants) compared hypertonic saline to mannitol but did not report lung function at relevant time points for this review; there were no differences in sputum clearance, but mannitol was reported to be more 'irritating' (very low-quality evidence).

AUTHORS' CONCLUSIONS

Regular use of nebulised hypertonic saline by adults and children over the age of 12 years with CF results in an improvement in lung function after four weeks (very low-quality evidence from three trials), but this was not sustained at 48 weeks (low-quality evidence from one trial). The review did show that nebulised hypertonic saline reduced the frequency of pulmonary exacerbations (although we found insufficient evidence for this outcome in children under six years of age) and may have a small effect on improvement in quality of life in adults.Evidence from one small cross-over trial in children indicates that rhDNase may lead to better lung function at three months; qualifying this we highlight that while the study did demonstrate that the improvement in FEV1 was greater with daily rHDNase, there were no differences seen in any of the secondary outcomes.Hypertonic saline does appear to be an effective adjunct to physiotherapy during acute exacerbations of lung disease in adults. However, for the outcomes assessed, the quality of the evidence ranged from very low to at best moderate, according to the GRADE criteria.

Lung function tests to monitor respiratory disease in preschool children

Pulmonary function tests are routinely used in the diagnosis and follow-up of respiratory diseases. In preschool children assessment and evaluation of lung function has always been challenging but improved techniques that require only minimal collaboration allowed obtaining reliable and useful results even in this group of patients. In this review we will describe the different techniques used in clinical practice to measure lung function in preschool children.(www.actabiomedica.it)