Table 1.
Overview of the effects of heat and moisture exchangers (HMEs) as reported in the included studies.
| Effect variables and resultsa | References | |
| Breathing | ||
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After 12 weeks of using an HME, only 1 patient (3.4%) found it more difficult to breathe through the HME, 7 patients (24.1%) felt no difference, and 21 (72.4%) patients found breathing through the HME less difficult (P=.002). | Macri et al [41], 2016 |
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At 6 weeks, 71% of the patients and at 3 months, 88% of the patients responded positively to the question “Are you breathing better?”. | Dassonville et al [40], 2011 |
| Shortness of breath | ||
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A statistically significant decrease in shortness of breath was demonstrated with a baseline value of 5.7 and a value of 3.8 after 6 and 12 weeks of Provox XtraHME (P<.0001) using structured questionnaires. | Parrilla et al [42], 2015 |
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Both the HME users and the no-HME control group experienced a decrease in shortness of breath at rest (HME group: P=.03; control group: P=.006). The HME users also experienced a significant increase in shortness of breath while climbing steps (P=.012). | Bień et al [28], 2010 |
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In total, 35% of the patients experienced lower breathing resistance with the first-generation HMEs, 25% experienced lower breathing resistance with the second-generation HMEs, and 40% experienced no difference between the 2 devices (P=.41). | Herranz et al [31], 2013 |
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Non-HME users, Provox Micron HMEs users (first generation), and Provox HME (first generation) users scored a 4.6, 4.9, and 4.3, respectively, on the Quality-of-Life Questionnaire (P=.363). | Brook et al [16], 2013 |
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After 12 weeks of Provox XtraHME (second generation) use, 3.4% of the patients found it more difficult to breathe through the HME, 24.1% of the patients felt no difference, and 72.4% of the patients found breathing through the HME less difficult (P=.002). | Macri et al [41], 2016 |
| Tracheal climate | ||
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|
After 2 weeks of Provox XtraHME (second generation) use, 60% of the patients reported less tracheal dryness or irritation and 40% reported no changes, compared with no HME use at baseline. After 12 weeks, 82.8% of the patients reported less irritation, 13.8% reported no changes, and 3.4% reported more irritation (P=.013). | Parrilla et al [42], 2015 |
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|
After 12 weeks, 82.8% of the HME-using patients reported less irritation, 13.8% reported no changes, and 3.4% reported more irritation (P=.013). | Macri et al [41], 2016 |
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Patients reported significantly less tracheal dryness with the second-generation HMEs (38%) than with the first-generation HMEs (14%) (P=.039). Moreover, 42.5% of the patients preferred the second-generation HMEs, 40% preferred the first-generation HMEs, and 17.5% had no preference. | Herranz et al [31], 2013 |
| Mucus production or plugging | ||
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The rate of mucus plugging was significantly lower in the XtraHME group than in the EHb group (0.13 and 0.38 per 10 inpatient days, respectively, P=.02). The proportion of patients with ≥1 mucus plug events was also significantly reduced in the HME group (50% in the EH group and 11% in the HME group, P=.01) in the postoperative period. | Ebersole et al [43], 2020 |
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After 2 weeks of Provox XtraHME (second generation) use, there was statistically significantly less mucus production in patients. | Parrilla et al [42], 2015 |
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Of those experiencing mucus plugging, 12.5% had used an HME, in contrast to 87.5% who used an EH. There was a significant difference between case and control groups based on use of an HME (χ2=9.4, P=.002). The odds ratio of a mucus plug event when not using HME was 8.27. | Foreman et al [44], 2016 |
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After 12 weeks of use, 36% of the patients reported less mucus production with the first-generation HME, 26% reported less mucus production with the second-generation HME, and 41% reported no difference (P=.162). | Herranz et al [31], 2013 |
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After 12 weeks of Provox XtraHME use, 79.3% of the patients reported less mucus production, 6.9% reported more mucus production, and 13.8% reported the same mucus production (P=.368). | Macri et al [41], 2016 |
| Coughing | ||
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At baseline (control) and after 2, 6, and 12 weeks of XtraHME use, the average number of daily coughs was 8.8, 4.6, 3.5, and 2.4, respectively (P<.001). After 2 weeks of HME use, the patients reported less coughing (63.3%) compared with the baseline phase. After 6 and 12 weeks of HME use, the patients did not report any further change in coughing (P=.337). | Parrilla et al [42], 2015 |
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At 3 months, there was a significant decrease in coughing in the HME group versus the no-HME control group (P=.00174). By means of an analog scale ranging from 0 to 10, the baseline value was 4, and after 2 months, this value dropped to 2. | Dassonville et al [40], 2011 |
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A decrease was observed in the frequency of coughing in the HME group (P<.001). In the control group, the frequency of coughing in week 1 was 60 times and in week 12, 56 times. In the HME group, this was 48 and 30, respectively. | Bień et al [28], 2010 |
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The number of coughing episodes were significantly lower in the HME arm (P<.001). In the EH group, 73% of the patients had 2 to 10 spontaneous coughing episodes per day, whereas 8% had 20, another 8% had 30, and 4% had 72 episodes a day (for 8%, this information was missing). In the HME group, most patients (90%) had 1 to 5 spontaneous coughing episodes per day, whereas 4.3% had 10 and another 4.3% had 20 such episodes per day. | Mérol et al [29], 2012 |
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After 2 weeks of HME use, 63.3% of the patients reported less coughing compared with the baseline period. After 6 and 12 weeks of HME use, 83.3% and 89.7% of the patients, respectively, did not reported any further change in coughing (P=.337). | Macri et al [41], 2016 |
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The combined number of coughs and forced expectorations using the first- and second-generation HMEs was similar (P=.304). The average daily coughing frequency was lower when using the second-generation HMEs (2.0 vs 2.59 per day). Most patients (51%) felt no difference between the 2 HMEs (P=.275) or reported that the second-generation HMEs performed better (35% vs 22%). | Herranz et al [31], 2013 |
| Forced expectorations | ||
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A significant decrease in forced expectoration was reported in the XtraHME (second generation) group versus the control group (P<.0001). At baseline (control) and after 2, 6, and 12 weeks of Provox XtraHME use, the average number of daily forced expectorations was 6.3, 3.0, 2.3, and 1.9, respectively. | Parrilla et al [42], 2015 |
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A decrease in the frequency of forced expectorations (P<.001) was found in the HME group compared with the control group. In the control group, the frequency of forced expectorations in week 1 was 59 and in week 12, 53. In the HME group, this was 56 and 27, respectively. | Bień et al [28], 2010 |
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The frequency of mucus expectoration for clearing the trachea was significantly lower in the HME arm (P<.001). In the EH group, the mean frequency of mucus expectoration was 5.5 times per day and in the HME group (first generation), 2.5 times per day. | Mérol et al [29], 2012 |
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The combined number of coughs and forced expectorations using the first- and second-generation HMEs was similar (P=.304 and P=.764, respectively). The maximum number of forced expectorations was lower using the second-generation HME (12 vs 20 times per day). In total, 47% experienced no difference between the 2 generation HMEs, 23% experienced less forced expectoration with the first-generation HMEs, and 30% experienced less forced expectoration with the second-generation HMEs (P=.513). | Herranz et al [31], 2013 |
| Sleep quality | ||
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A statistically significant improvement in sleep quality with a baseline value of 7.1 and a value of 6.2 (a lower score indicates less burden for the patient) after 12 weeks of Provox XtraHME use (P=.004) was reported in the structured questionnaires. | Parrilla et al [42], 2015 |
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Sleeping disturbances were significantly lower in the HME group (P<.001): 83% of patients in the HME group arm did not experience any sleeping discomfort over the hospitalization period, whereas 17% mentioned some sleeping discomfort. | Mérol et al [29], 2012 |
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No significant difference was reported between the HME group and EH group in sleep quality. | Foreman et al [44], 2016 |
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Patients did not report a difference in sleeping when using the first- or second-generation HME (72%). | Herranz et al [31], 2013 |
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In the control group, almost all the patients (97.5%) had sleeping problems, and this did not change over time. In the full-compliance HME group (first generation), 79% of the patients had sleeping problems at baseline, and 72% had this problem after 3 months of HME use. This reduction was not significant. | Bień et al [28], 2010 |
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Non-HME users, Provox Micron HMEs users, and Provox HME users scored a 4.5, 4.8, and 4.6, respectively, on the Quality-of-Life Questionnaire (P=.913). | Brook et al [16], 2013 |
| Speech quality | ||
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A statistically significant improvement in speech quality, with a baseline value of 12.3 versus 10.3 after 12 weeks of Provox XtraHME (P<.0001) use, was reported in the structured questionnaires (a lower score indicates a lower burden for the patient). | Parrilla et al [42], 2015 |
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At 6 weeks, 80% of the patients experienced a statistically nonsignificant improvement in stoma occlusion with more powerful and more audible phonation. At 3 months, this number rose to 94%. At 6 weeks, 52% of the patients using a voice implant and an HME showed an improvement in the intensity of the prosthetic voice, and at 3 months, this value increased to 71% (>5 on the analog scale). Regarding the fluency of speech, 62% of the patients experienced a nonsignificant improvement after 6 weeks of HME use, which increased to 76% after 3 months. Moreover, 71% of the patients had perceived vocal improvement at 6 weeks, and 81% had perceived vocal improvement at 3 months. | Dassonville et al [40], 2011 |
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The HME users and Micron users reported a better voice than did the non-HME users (not statistically significant). Non-HME users, Provox Micron HMEs users, and Provox HME users scored a 7.6, 9.4, and 8.0, respectively, on the Quality-of-Life Questionnaire (P=.396). | Brook et al [16], 2013 |
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No significant change was reported in voice and speech aspects over time in the control and HME group. A trend was seen for the prosthetic speakers to report more fluent speech with HME use (P=.073). | Bień et al [28], 2010 |
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After 6 weeks of use, no difference was reported in speech intelligibility and voice (72%, P=.739) between Provox HME (first generation) and Provox XtraHME (second generation) users. | Herranz et al [31], 2013 |
| Psychosocial aspects | ||
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Patients reported no differences concerning psychosocial aspects. Among both patients using the first-generation HMEs and those using the second-generation HMEs, over 75% reported to have no problems, socially or psychologically. | Herranz et al [31], 2013 |
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At baseline, most patients (80%-90%) reported no or only slight problems with anxiety and depression, which had significantly increased in the control group (no HME use; P=.003); however, in the HME groups (first generation), no significant changes were found. | Bień et al [28], 2010 |
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A statistically significant improvement in psychological stress, with a baseline value of 7.1 versus a value of 5.1 after 12 weeks of Provox XtraHME use (P<.001), was reported in the structured questionnaires (a lower score means less burden for the patient). | Parrilla et al [42], 2015 |
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Non-HME users, Provox Micron HMEs users, and Provox HME users scored a 5.8, 6.5, and 6.6, respectively, on the Quality-of-Life Questionnaire (P=.688). | Brook et al [16], 2013 |
| Physiotherapy | ||
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The use of Provox XtraHME significantly reduced the number of days requiring chest physiotherapy after surgery (1.75 vs 3.20 days, P=.034) compared with the use of EH. | Foreman et al [44], 2016 |
| Tracheobronchitis or pneumonia episodes | ||
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Among the non-HME users, 0.285 tracheobronchitis or pneumonia episodes was reported per patient per year, which was statistically higher than the 0.066 episodes reported per patient per year among the HME users (first generation; P=.047). Among the non-HME users, an average of 0.129 pulmonary infections (tracheobronchitis and pneumonia together) was documented per patient per year. Among the HME users (first generation), this average was 0.092 per patient per year (P=.33). | van den Boer et al [12], 2014 |
| Social contacts | ||
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Patients who use a Provox FreeHands device tended to have more frequent social contacts (r=0.251; P=.030). | Brook et al [16], 2013 |
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A statistically nonsignificant improvement in social contacts, with a baseline value of 8.1 versus a value 8.3 after 12 weeks (P=.728), was reported in the structured questionnaires when comparing no HME use with HME (second generation) use. | Parrilla et al [42], 2015 |
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Non-HME users, Provox Micron HME (first generation) users, and Provox HME (first generation) users scored a 9.6, 8.4, and 9.7, respectively, on the frequency of social contacts category from the Quality-of-Life Questionnaire (P=.438; a higher score indicates more problems). | Brook et al [16], 2013 |
| QoLc | ||
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The EQ-5D Index showed an increase throughout the study, with an increase from an average of 0.84 at baseline to 0.96 after 12 weeks of HME use (P<.001). The EQ-5D VASd scale showed an increase from 61.3 at baseline to 80.0 after 12 weeks of Provox XtraHME use (P<.0001). | Parrilla et al [42], 2015 |
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Among 60 patients, who were randomized between a control group that used no device and a group equipped with the Provox HME (first generation), 92% of the patients with the device perceived an improvement in their QoL at the end of 3 months (>5 on the analog scale). | Dassonville et al [40], 2011 |
| Patient satisfaction | ||
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Patients’ satisfaction showed a significant improvement of first-generation HME over EH (P<.001). Patient satisfaction with the EH was quite low: 11% of the patients reported that they were satisfied with it, 8% reported they somewhat liked it, and 81% reported that they did not like it. All the patients (100%) in the HME (first generation) group were satisfied with the device. | Mérol et al [29], 2012 |
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After 12 weeks of use, 60.7% of the patients were “very satisfied” with the use of the HME (first generation), and 39.3% were “satisfied.” None of the patients was dissatisfied with XtraHME (second generation). | Macri et al [41], 2016 |
aA P value is presented if reported in the paper.
bEH: external humidifier.
cQoL: quality of life.
dVAS: visual analog scale.