Abstract
Background:
Pneumonia after pulmonary resection occurs in 5–12% of patients and causes substantial morbidity. Oral hygiene regimens lower the incidence of ventilator-associated pneumonias, however, the impact in patients undergoing elective pulmonary resection is unknown. We conducted a prospective pilot study to assess the feasibility of an oral hygiene intervention in this patient cohort.
Methods:
Patients undergoing elective pulmonary resection were prospectively enrolled in a single arm interventional study with time-matched controls. Participants were asked to brush their teeth with 0.12% chlorhexidine three times daily for five days before their operations and five days or until the time of discharge after their operations. Patients were eligible if they had known or suspected lung cancer and were undergoing (1) any anatomic lung resection or (2) a wedge resection with FEV1 or DLCO <50% predicted.
Results:
62 patients were enrolled in the pilot intervention group and compared to a contemporaneous cohort of 611 patients who met surgical inclusion criteria. Preoperative adherence to the chlorhexidine toothbrushing regimen was high: median 100% (IQR: 87–100%). Postoperatively, 80% of patients continued toothbrushing, while 20% declined further participation. Among those who participated postoperatively, median adherence was 86% (IQR: 53–100%). There was a trend towards reduction in post-operative pneumonia: 1.6% (1/62) in the intervention cohort vs 4.9% (30/611) in the time-matched cohort (p=0.35). The number needed to treat to prevent one pneumonia was 30 patients.
Conclusions:
This pilot study demonstrated patients can comply with an inexpensive perioperative oral hygiene regimen that may be promising for reducing morbidity.
Postoperative pneumonia is a common complication after major pulmonary resections, with an incidence of 5–12% [1–4]. It results in significant morbidity, and can lead to reintubation or tracheostomy, critical illness, prolonged hospital stay, need for rehabilitation, and increased rates of unplanned readmission [5,6]. Pneumonia is also one of the primary causes of postoperative mortality following thoracic surgery [6,7]. Consequently, there is substantial interest in identifying strategies for risk reduction.
Investigations into the cause of health-care acquired pneumonia (HCAP) have identified aspiration of oral pathogens as a source for bacteria leading to pulmonary infections [8,9]. Poor dental hygiene and oral colonization with pathogenic organisms has been associated with the development of pneumonia in nursing home residents and hospitalized patients [10–12]. Correspondingly, strategies to improve dental care and reduce oral bacteria have shown promise in decreasing the risk of pneumonia: systematic reviews of randomized trials demonstrated that chlorhexidine-based oral cleansing regimens decrease rates of HCAP, with an absolute risk reduction of 6% in mechanically ventilated patients [13] and between 6–12% in elderly individuals [14]. Based on the encouraging results with simple and inexpensive oral decontamination in these populations, there may be a role for dental hygiene in the perioperative period, especially in patients that are at high risk of postoperative pneumonia.
Within the field of thoracic surgery, there is limited data regarding the effectiveness of perioperative oral hygiene in reducing the risk of pneumonia following elective operations. One small study of preoperative toothbrushing showed pneumonia rates following esophagectomy could be reduced from 32% to 9% by brushing five times daily, and the effect was greater in a subgroup of patients whose oral flora was positive for pathogenic bacteria prior to intervention [15]. A larger propensity score matched study of 420 patients showed intensive oral care including professional tooth and tongue cleanings by dentists or hygienists was associated with an odd ratio of 0.37 (95% CI: 0.20–0.65) for developing postoperative pneumonia [16]. The impact of perioperative oral hygiene improvement in patients undergoing elective pulmonary resection, however, is unknown.
We conducted a prospective pilot study to assess the feasibility of implementing a short-term perioperative oral hygiene intervention in a cohort of patients undergoing pulmonary resection. We hypothesized that our intervention would have high patient adherence and lower the risk of postoperative pneumonia after lung resection.
PATIENTS AND METHODS
Patient eligibility and data sources
Patients undergoing elective pulmonary resection were prospectively enrolled in a single arm interventional study and compared with time-matched controls. Adult patients (age ≥18 years) were eligible for inclusion if they had known or suspected lung cancer and were either undergoing [1] any anatomic lung resection or [2] a wedge resection and had either FEV1 or DLCO <50% predicted (FEV1: forced expiratory volume in one second, DLCO: diffusing capacity of the lungs for carbon monoxide). Data on patient demographics, comorbidities, pulmonary function tests (PFTs), operative procedure, and postoperative outcomes for patients in both the intervention and control groups were obtained from a prospectively maintained institutional database. Data on patient adherence to the intervention were collected during the period of the study. Patients were approached by a study coordinator and enrolled using convenience sampling. This study was approved by the IRB at Washington University in St. Louis and all patients participating in the intervention provided informed consent.
Clinical Intervention
Participants in the study group (postoperative pneumonia prevention (POPP) cohort) were asked to brush their teeth with 0.12% chlorhexidine solution three times daily [17,18] in the perioperative period. To encourage adherence, participants were each given one toothbrush, a supply of chlorhexidine solution for brushing (provided by Sage Products, Inc.), and a log sheet for recording their perioperative oral hygiene. Patients were asked to brush for five days preoperatively, and until the time of discharge or five days postoperatively if they remained hospitalized. This facilitated collection of patient logs prior to discharge on which their adherence with the toothbrushing episodes were recorded in real-time. Patients were excluded if they did not subsequently undergo a qualifying operation, developed a preoperative infection, or withdrew prior to participating in the intervention.
The contemporaneous cohort consisted of all patients meeting our inclusion criteria for enrollment who received their operation during the time period of the study. A time-matched cohort was selected to control for unmeasured institutional factors that could affect pneumonia risk. The control group was not given any specific instructions about oral hygiene.
All patients received standard perioperative care at our institution including, as indicated: smoking cessation counseling, preoperative pulmonary rehabilitation, appropriate resection based on PFTs, minimally invasive surgery if possible, and early postoperative ambulation, physical therapy, and incentive spirometry.
A summary of patient selection criteria and intervention can be seen in our Consolidated Standards of Reporting Trials (CONSORT) diagram in Figure 1.
Fig 1.
Consolidated Standards of Reporting Trials (CONSORT) flow diagram. (DLCO = diffusing capacity of lungs for carbon monoxide; FEV1 = forced expiratory volume in 1 second; PFTs = pulmonary function tests; POPP = prevention of postoperative pneumonia; Pre-op = preoperative; Rehab = rehabilitation.)
Outcomes
Adherence to the toothbrushing regimen was assessed preoperatively and postoperatively in the study group. Preoperative percent adherence was defined as the number of times the patient brushed out of a possible fifteen. Postoperative percent adherence was defined as the number of times the patient brushed out of the total number possible (three per inpatient day and on the day of discharge any episodes prior to their departure, up to fifteen if they were hospitalized beyond five days).
Postoperative pneumonia was defined as per Society of Thoracic Surgeons (STS) guidelines [19] and assessed in both groups. Patients were followed up according to routine institutional practice which included a postoperative clinic visit at approximately 4 weeks. The presence or absence of pneumonia was verified by chart review of the initial hospitalization, any readmissions, and follow up appointments through 30 days. This assessment was performed in both the POPP and contemporaneous cohorts by a trained research assistant using STS criteria, and individual surgeons were not involved in classification. Patients were considered to have postoperative pneumonia if they met three of the following criteria within 30 days after surgery: 1) fever (temperature >38.2 C), 2) leukocytosis (WBC>12,000/cu mm), 3) new infiltrate on chest x-ray, 4) positive sputum or bronchial culture, 5) treatment with antibiotics. As one of their three criteria, patients were required to either have an infiltrate or a positive respiratory culture.
Statistical Analysis
Statistical analyses were performed using SAS statistical software version 9.3 (SAS Institute, Inc., Cary, NC). Descriptive statistics were performed comparing patient demographics, PFTs, comorbidities, operative characteristics, and outcomes between both cohorts. Continuous variables were compared between groups using the Wilcoxon rank sum test. Categorical variables were compared with chi-square tests and Fisher’s exact tests, as appropriate. Univariable analyses were then performed to assess the unadjusted association of each variable with postoperative pneumonia.
RESULTS
Patient Population
Sixty two patients were enrolled in the intervention group (POPP cohort) from October 2012 to November 2015. These patients were compared to a contemporaneous cohort of 611 patients who met the surgical inclusion criteria during the same time period. There were no statistically significant differences between the POPP cohort and the contemporaneous cohort, respectively, in: age (mean: 63.5 vs 63.2 years), gender (53.2% vs 45.5% male), race (91.9% vs 90.1% white), FEV1 (79.5% vs 81.0%), DLCO (67.3% vs 69.1%), rates of major medical comorbidities, pulmonary resection performed (71.0% vs 65.8% lobectomy), or surgical approach (56.5% vs 56.6% VATS). This indicates the POPP cohort was representative of the general patient population undergoing pulmonary resection at our institution. These characteristics are shown in Table 1.
Table 1.
Patient Characteristics.
| POPP Cohort | Contemporaneous Cohort | ||
|---|---|---|---|
| Variable | n=62 | n=611 | p |
| Patient Characteristics | |||
| Age (mean±SD) | 63.5 ± 8.6 | 63.2 ± 11.4 | 0.943 |
| Male Gender | 53.2% (33) | 45.5% (278) | 0.245 |
| Race: White | 91.9% (57) | 90.1% (551) | 0.686 |
| Black | 8.1% (5) | 8.7% (53) | |
| Other | - | 1.2% (7) | |
| Body Mass Index (mean±SD) | 29.1± 6.7 | 27.8 ± 6.2 | 0.138 |
| Pulmonary Function Tests | |||
| FEV1 (%Predicted) (mean±SD) | 79.5% ± 18.5% | 81.0% ± 19.5% | 0.853 |
| DLCO (%Predicted) (mean±SD) | 67.3% ± 17.7% | 69.1% ± 20.0% | 0.734 |
| Comorbidities | |||
| COPD | 17.7% (11) | 28.3% (173) | 0.075 |
| Smoking: Current | 22.6% (14) | 29.0% (177) | 0.566 |
| Former | 58.1% (36) | 53.7% (328) | |
| Never | 19.4% (12) | 17.4% (106) | |
| Lung Cancer | 90.3% (56) | 86.4% (528) | 0.387 |
| Pathologic Stage 0 | - | 2.3% (14) | 0.662 |
| I | 53.2% (33) | 47.0% (287) | |
| II | 22.6% (14) | 22.1% (135) | |
| III | 11.3% (7) | 10.2% (62) | |
| IV | - | 2.3% (14) | |
| unknown | 3.2% (2) | 2.6% (16) | |
| Preoperative Chemotherapy | 12.9% (8) | 6.4% (39) | 0.066 |
| Preoperative Radiation | 11.3% (7) | 9.2% (56) | 0.584 |
| Prior Lung Cancer | 4.8% (3) | 3.0% (18) | 0.431 |
| Prior Cardiothoracic Surgery | 11.3% (7) | 9.8% (60) | 0.713 |
| Cardiovascular Disease | 22.6% (14) | 19.0% (116) | 0.494 |
| Congestive Heart Failure | - | 0.8% (5) | 0.475 |
| Diabetes | 17.7% (11) | 13.4% (82) | 0.348 |
| Prior Other Cancer | 32.2% (20) | 29.3% (179) | 0.626 |
| Immunosuppression | 4.8% (3) | 2.8% (17) | 0.418 |
| Procedure Characteristics | |||
| Operation: | |||
| Lobectomy | 71.0% (44) | 65.8% (402) | 0.861 |
| Pneumonectomy | 6.5% (4) | 7.6% (46) | |
| Bilobectomy | 4.8% (3) | 5.4% (33) | |
| Sleeve | 3.2% (2) | 2.8% (17) | |
| Segmentectomy | 6.5% (4) | 9.8% (60) | |
| Wedge | 4.8% (3) | 7.2% (44) | |
| Lung & Chest Wall Resection | 3.2% (2) | 1.5% (9) | |
| VATS Approach | 56.5% (35) | 56.6% (346) | 0.979 |
| Outcome | |||
| Pneumonia | 1.6% (1) | 4.9% (30) | 0.348 |
Values are reported as % of cohort (number of patients) unless otherwise specified. Cardiovascular Disease includes coronary artery disease or peripheral vascular disease.
Adherence
Within the study group, preoperative adherence to the toothbrushing regimen was high: median 100% (IQR: 87–100%). Postoperatively, 80% continued toothbrushing, while 20% declined further participation and performed no additional episodes of toothbrushing. Among those who participated postoperatively, median adherence was 86% (IQR: 53–100%).
We observed that 40% (25/62) of patients had excellent adherence to the protocol: defined as performing ≥80% of the recommended episodes of toothbrushing preoperatively and ≥80% of the recommended episodes of toothbrushing postoperatively. The highly adherent patients were more likely to be white (100% vs 81.1%, p=0.07) and had higher rates of VATS procedures (72.0% vs 40.5%, p=0.03). Characteristics by adherence rates are shown in Table 2. On multivariable analysis, the only characteristic associated with excellent adherence to the toothbrushing regimen was VATS approach (OR 3.26, 95% CI: 1.08–9.83, p=0.04).
Table 2.
Adherence within the POPP Cohort
| ≥80% Adherence | <80% Adherence | ||
|---|---|---|---|
| Variable | n=25 | n=37 | p |
| Patient Characteristics | |||
| Age (mean±SD) | 62.1 ± 7.4 | 64.4 ± 8.7 | 0.385 |
| Gender (%Male) | 52.0% (13) | 48.7% (18) | 0.344 |
| Race (%White) | 100% (25) | 81.1% (30) | 0.070 |
| BMI (mean±SD) | 28.6 ± 6.0 | 28.5 ± 6.6 | 0.460 |
| Pulmonary Function Tests | |||
| FEV1 (%Predicted) (mean±SD) | 80.3% ± 18.7% | 78.6% ± 19.2% | 0.643 |
| DLCO (%Predicted) (mean±SD) | 67.8% ± 20.1% | 67.0% ± 15.9% | 0.733 |
| Comorbidities | |||
| COPD | 16.0% (4) | 18.9% (7) | 0.312 |
| Smoking (%Current) | 28.0% (7) | 16.2% (6) | 0.274 |
| (%Former) | 60.0% (15) | 54.1% (20) | |
| (%Never) | 12.0% (3) | 21.6% (8) | |
| Lung Cancer | 88.0% (22) | 86.5% (32) | 0.242 |
| Preoperative Chemotherapy | 8.0% (2) | 16.2% (6) | 0.193 |
| Preoperative Radiation | 8.0% (2) | 13.5% (5) | 0.252 |
| Prior Cardiothoracic Surgery | 8.0% (2) | 13.5% (5) | 0.252 |
| Cardiovascular Disease | 16.0% (4) | 21.6% (8) | 0.267 |
| Diabetes | 12.0% (3) | 16.2% (6) | 0.288 |
| Prior Other Cancer | 32.0% (8) | 27.0% (10) | 0.337 |
| Procedure Characteristics | |||
| Operation | |||
| Lobectomy | 72.0% (18) | 62.2% (23) | 0.642 |
| Pneumonectomy | 4.0% (1) | 8.1% (3) | |
| Bilobectomy | 4.0% (1) | 5.4% (2) | |
| Sleeve | - | 5.4% (2) | |
| Segmentectomy | 8.0% (2) | 5.4% (2) | |
| Wedge | 8.0% (2) | 2.7% (1) | |
| Lung & Chest Wall Resection | 4.0% (1) | 2.7% (1) | |
| Approach (%VATS) | 72.0% (18) | 40.5% (15) | 0.034 |
| Outcomes | |||
| Pneumonia Rate | - | 2.7% (1) | 0.236 |
Postoperative Pneumonia
There was a trend towards reduction in postoperative pneumonia: 1.6% (1/62) in the intervention cohort vs 4.9% (30/611) in the controls. The difference did not reach statistical significance (p=0.35) in this pilot study (Table 1). Patients who developed pneumonia had a postoperative median stay of 7 days (range: 2–84 days) compared to 4 days for patients without pneumonia (range: 0–49 days) (p<0.001). Variables associated with development of postoperative pneumonia included: open approach (p<0.001), cardiovascular disease (p=0.002), DLCO (p=0.003), FEV1 (p=0.01), and prior lung cancer (p=0.04) (Table 3). Participation in the intervention showed an odds ratio of 0.32 (95% CI 0.04–2.37, p=0.26) for development of postoperative pneumonia. Based on the observed incidence, the number needed to treat to prevent one pneumonia was 30 patients.
Table 3.
Univariable Analyses – Associations of Postoperative Pneumonia
| Variable | Univariable OR (95% CI) |
p |
|---|---|---|
|
Participated in POPP Cohort |
0.32 (0.04–2.37) |
0.263 |
|
Patient Characteristics |
||
| Age | 0.98 (0.95–1.02) | 0.306 |
| Gender Female vs Male | 0.53 (0.25–1.10) | 0.089 |
| Race Non-white vs White | 0.63 (0.15–2.72) | 0.539 |
| BMI | 0.96 (0.90–1.02) | 0.217 |
|
Pulmonary Function Tests |
||
| FEV1 (% Predicted) | 0.98 (0.96–1.00) | 0.013 |
| DLCO (% Predicted) | 0.97 (0.94–0.99) | 0.003 |
|
Comorbidities |
||
| COPD | 1.73 (0.82–3.63) | 0.150 |
| Smoking Current vs Never | 1.25 (0.37–4.23) | 0.725 |
| Former vs Never | 1.57 (0.52–4.71) | 0.421 |
| Lung Cancer | 0.50 (0.21–1.20) | 0.122 |
| Preoperative Chemotherapy | 2.06 (0.69–6.17) | 0.194 |
| Preoperative Radiation | 1.46 (0.50–4.33) | 0.491 |
| Prior Lung Cancer | 3.72 (1.03–13.35) | 0.044 |
| Prior Cardiothoracic Surgery | 1.36 (0.46–4.02) | 0.576 |
| Cardiovascular Disease | 3.21 (1.55–6.80) | 0.002 |
| Diabetes | 0.92 (0.32–2.69) | 0.880 |
| Prior Other Cancer | 0.56 (0.23–1.38) | 0.208 |
| Immunosuppression | 1.09 (0.14–8.44) | 0.932 |
|
Procedure Characteristics |
||
| Operation | ||
| Pneumonectomy | 2.64 (0.94–7.46) | 0.066 |
| Bilobectomy | 1.40 (0.31–6.28) | 0.662 |
| Sleeve | 1.32 (0.17–10.45) | 0.792 |
| Segmentectomy | 0.77 (0.17–3.39) | 0.726 |
| Wedge | 1.06 (0.24–4.70) | 0.942 |
| Lung & Chest Wall | 2.38 (0.29–19.59) | 0.421 |
| Resection | ||
| Approach VATS vs Open | 0.21 (0.09–0.49) | <0.001 |
The single case of postoperative pneumonia in the POPP cohort was in a 61-year-old, white, male, former smoker with cardiovascular disease who underwent a thoracotomy and lobectomy with preoperative PFTs: FEV1 75% of predicted and DLCO 62% of predicted. He was 73% adherent to his preoperative toothbrushing regimen and 64% adherent to his postoperative regimen.
Open Operation Subgroup Analysis
Since an open operation was strongly associated with postoperative pneumonia, we performed a subgroup analysis in this population. Twenty seven patients within the POPP cohort and 265 patients in the contemporaneous cohort underwent a thoracotomy. There were no significant differences in clinical characteristics, PFTs, comorbidities, or procedure characteristics between these subgroups (Table 4). The pneumonia rate was 3.7% (1/27) in the POPP cohort and 8.7% (23/265) in the contemporaneous cohort, which was not statistically significant in this pilot study (p=0.71). Participation in the intervention showed an odds ratio of 0.40 (95% CI: 0.05–3.12, p=0.39) for the development of pneumonia on univariable analysis (Table 5).
Table 4.
Comparison of Characteristics Between Groups - Open Operation Subgroup Analysis
| POPP Cohort | Contemporaneous Cohort | ||
|---|---|---|---|
| Variable | n=27 | n=265 | p |
| Patient Characteristics | |||
| Age (mean±SD) | 65.0 ± 6.3 | 61.9 ±11.9 | 0.261 |
| Gender (%Male) | 59.3% (16) | 51.7% (137) | 0.454 |
| Race (%White) | 96.3% (26) | 91.3% (242) | 0.654 |
| (%Black) | 3.7% (1) | 7.9% (21) | |
| BMI (mean±SD) | 29.4 ± 7.7 | 28.3 ± 6.4 | 0.709 |
| Pulmonary Function Tests | |||
| FEV1 (%Predicted) (mean±SD) | 75.9% ± 21.5% | 77.9% ± 17.8% | 0.716 |
| DLCO (%Predicted) (mean±SD) | 64.5% ± 20.2% | 65.6% ± 18.4% | 0.991 |
| Comorbidities | |||
| COPD | 25.9% (7) | 32.1% (85) | 0.665 |
| Smoking (%Current) | 22.2% (6) | 28.7% (76) | 0.290 |
| (%Former) | 70.4% (19) | 55.5% (147) | |
| (%Never) | 7.4% (2) | 15.9% (42) | |
| Lung Cancer | 92.6% (25) | 87.9% (233) | 0.752 |
| Preoperative Chemotherapy | 22.2% (6) | 13.2% (35) | 0.240 |
| Preoperative Radiation | 14.8% (4) | 15.1% (40) | 1.000 |
| Prior Lung Cancer | 11.1% (3) | 4.2% (11) | 0.129 |
| Prior Cardiothoracic Surgery | 14.8% (4) | 12.1% (32) | 0.757 |
| Cardiovascular Disease | 25.9% (7) | 20.0% (53) | 0.458 |
| Diabetes | 14.8% (4) | 16.2% (43) | 1.000 |
| Prior Other Cancer | 25.9% (7) | 22.3% (59) | 0.635 |
| Procedure Characteristics | |||
| Operation | 0.918 | ||
| Lobectomy | 51.9% (14) | 53.6% (142) | |
| Pneumonectomy | 14.8% (4) | 17.4% (46) | |
| Bilobectomy | 11.1% (3) | 9.1% (24) | |
| Sleeve | 7.4% (2) | 6.4% (17) | |
| Segmentectomy | 7.4% (2) | 7.6% (20) | |
| Wedge | - | 2.6% (7) | |
| Lung & Chest Wall Resection |
7.4% (2) | 3.4% (9) | |
| Outcomes | |||
| Pneumonia Rate | 3.7% (1) | 8.7% (23) | 0.710 |
Table 5.
Univariable Analyses - Open Operation Subgroup Analysis
| Variable |
Univariable OR (95% CI) |
p |
|---|---|---|
|
Part of POPP Cohort (n=27) vs Contemporaneous Cohort (n=265) |
0.40 (0.05–3.12) |
0.386 |
|
Patient Characteristics |
||
| Age | 0.99 (0.95–1.02) | 0.397 |
| Gender Female vs Male | 0.64 (0.27–1.51) | 0.304 |
| Race Non-white vs White | 1.02 (0.22–4.61) | 0.983 |
| BMI | 0.92 (0.85–1.00) | 0.051 |
|
Pulmonary Function Tests |
||
| FEV1 (% Predicted) | 0.99 (0.96–1.01) | 0.250 |
| DLCO (% Predicted) | 0.98 (0.96–1.01) | 0.214 |
|
Comorbidities |
||
| COPD | 1.34 (0.56–3.18) | 0.511 |
| Smoking Current vs Never | 0.51 (0.12–2.16) | 0.441 |
| Former vs Never | 1.07 (0.34–3.37) | |
| Lung Cancer | 0.27 (0.10–0.72) | 0.008 |
| Preoperative Chemotherapy | 1.25 (0.40–3.86) | 0.700 |
| Preoperative Radiation | 1.14 (0.37–3.51) | 0.819 |
| Prior Lung Cancer | 1.94 (0.41–9.22) | 0.405 |
| Prior Cardiothoracic Surgery | 1.02 (0.29–3.60) | 0.979 |
| Cardiovascular Disease | 2.08 (0.84–5.11) | 0.112 |
| Diabetes | 0.45 (0.10–1.98) | 0.292 |
| Prior Other Cancer | 0.29 (0.07–1.27) | 0.100 |
|
Procedure Characteristics |
||
| Operation (Reference: Lobectomy) | 0.768 | |
| Pneumonectomy | 1.22 (0.41–3.62) | |
| Bilobectomy | 0.88 (0.19–4.14) | |
| Sleeve | 0.61 (0.08–4.95) | |
| Wedge | 4.40 (0.776–24.95) | |
| Lung & Chest Wall Resection |
1.10 (0.13–9.28) |
Cost Analysis
In this study, a 16 ounce bottle of 0.12% chlorhexidine solution cost $3.72 and bulk-ordered toothbrushes cost $0.19 each. With a number needed to treat in the study population of 30, the cost of preventing one pneumonia was $117. Currently, an inexpensive toothbrush retails for approximately $1.50 and the outpatient pharmacy at our institution sells oral chlorhexidine solution for approximately $15 without insurance. Using these prices, the estimated cost to prevent one postoperative pneumonia would be $495, while costs attributable to prolonged hospitalization from pneumonia range from $5,000-$17,000 [20,21] per patient.
COMMENT
Pneumonia after pulmonary resection not only contributes to significant morbidity, critical illness, costly prolonged hospital stays, and readmissions, but is one of the most lethal complications that a patient can develop [6,7]. Evidence-based strategies, including minimally invasive operations and smoking cessation counseling, have been employed for risk reduction in the thoracic surgery population, but additional interventions are needed to prevent pneumonia in this high-risk population.
In this study, we demonstrated the feasibility of implementing an oral hygiene regimen in patients undergoing major pulmonary resection. We found extremely high rates of preoperative adherence (median: 100% adherence) and acceptable postoperative adherence (80% participation), with very few patients withdrawing after agreeing to participate in the intervention. These rates are somewhat better than previously reported adherence rates with other forms of preoperative decontamination [22]. Additionally, this pilot study showed an encouraging trend towards lower rates of pneumonia overall (1.6% vs 4.9%). Our institutional incidence of pneumonia after pulmonary resection was 86% of the NSQIP risk-adjusted expected rate during the study period, and this intervention may have the potential to lower the incidence further. Analysis of risk factors for non-adherence showed that patients who underwent a thoracotomy were less likely to comply with the toothbrushing regimen. Unfortunately, these patients generally are at higher risk for postoperative pneumonia. Our subgroup analysis of open operations showed a similar trend towards decreased pneumonia rates in the POPP cohort undergoing thoracotomy (3.7% vs 8.7%), so future studies of oral hygiene regimens may benefit from targeted interventions to increase adherence in this subpopulation, focused surveys to understand reasons for noncompliance, and stratified analysis of these patients. Additionally, while not statistically significant in this pilot study, we found that less adherent patients were slightly older, more likely to be of a minority race, and have higher rates of comorbidities. This analysis suggests that when directing resources, vulnerable populations may benefit from additional efforts to encourage the intervention.
This study’s limitations merit discussion. First, this was a small pilot study that examined patient adherence, and was not powered to detect a statistical difference in the rates of postoperative pneumonia, which is the ultimate clinical outcome of interest. The purpose of tracking pneumonia in this pilot study was to establish proof of concept and obtain a point estimate of the potential risk reduction of the intervention, facilitating an appropriate sample size calculation for a future study. A larger trial is needed to determine whether the encouraging preliminary results seen here are a true consequence of the oral hygiene intervention. Additionally, the patients were not randomized in this single arm study; patients who consented may have been more willing to perform the intervention, which may have introduced bias, particularly with regards to adherence.
These limitations are balanced by several major strengths. This was a prospective intervention with clearly-defined, easy-to-measure endpoints of adherence and pneumonia. A systematic review demonstrated that self-reporting questionnaires like the patient diary utilized capture adherence with moderate-to-high reliability in the majority of studies [23]. Consequently, the observed high rates of perioperative toothbrushing suggest that this is a feasible intervention for thoracic surgery patients. Pneumonia was defined by STS criteria and a chart review was performed for all patients during the time period of the study, ensuring accuracy of this metric. Given the substantial morbidity and mortality of this common complication, there is certainly a role for identifying promising preventative interventions. Furthermore, our study shows significantly shorter lengths of stay in patients without pneumonia and our preliminary cost analysis demonstrates a potential cost-savings of >$4,500 per pneumonia prevented: this intervention has the potential to be highly cost-effective.
This pilot study demonstrated that this perioperative oral hygiene regimen can be implemented with high rates of adherence in patients undergoing planned lung resection. Additionally, the encouraging trend of lower rates of postoperative pneumonia suggests that this simple and inexpensive intervention may be promising for reducing morbidity after pulmonary resection. This pilot study established proof of concept for a chlorhexidine toothbrushing intervention that merits further investigation in a larger, multicenter trial, which is being planned.
Abbreviations:
- POPP
prevention of postoperative pneumonia
- HCAP
health-care acquired pneumonia
- PFTs
pulmonary function tests
- FEV1
forced expiratory volume in one second
- DLCO
diffusing capacity of the lungs for carbon monoxide
- STS
Society for Thoracic Surgeons
- VATS
video assisted thoracoscopic surgery
- BMI
body mass index
- COPD
chronic obstructive pulmonary disease
Footnotes
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Clinical Trials Registry: NCT01446874
References:
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