INTRODUCTION

Individuals with spinal cord injury (SCI) have significantly lower life expectancies than the general population.1 Life expectancy following spinal injury varies based on severity and age at injury. Among those who survive at least 1 year postinjury, the life expectancy for a 20-year-old is 52 years for an ASIA D SCI (incomplete motor function at any level), 45 years if the individual is paraplegic, 40 years if low quadriplegic (tetraplegic) (C5-C8), and 37 years if high tetraplegic (C1-C4). In contrast, life expectancy is only 25 years among ventilator-dependent persons at any level. An individual injured at the age of 60 years has a life expectancy of 18 years if ASIA D SCI, 13 years if paraplegic, 10 years if low tetraplegic, 8 years if high tetraplegic, and 4 years if ventilator-dependent at any level.1

The leading causes of death among persons with SCI are pneumonia and sepsis.1 Smoking increases the risk for pneumonia and is a modifiable risk factor for pressure injuries, which can lead to sepsis.2 Therefore, knowledge of smoking cessation strategies is especially important for clinicians who are caring for patients with SCI.3

Multiple studies have identified negative influences of smoking on overall health.4 Cigarette smoke contains more than 7000 chemicals and chemical compounds, including some that are carcinogenic and toxic to multiple organs. Smoking is associated with peripheral vascular disease and increases the risk of stroke 2- to 4-fold; it is associated with 90% of lung cancer deaths in men and 80% of lung cancer deaths in women. The Centers for Disease Control and Prevention reports that adverse effects of smoking account for approximately 443,000 deaths each year.4

Pressure injuries are prevalent in the SCI population, and they are the second leading cause of hospital readmission.5 Smoking is also associated with impaired wound healing among persons with SCI.6 Associated complications of smoking in this vulnerable population include higher rates of surgical wound dehiscence and flap coverage failure.7 McDaniel and Browning8 reported on the effects of smoking on chronic wound healing and revealed that although cigarettes contain thousands of toxic compounds, nicotine, carbon monoxide, and hydrogen cyanide are most closely associated with tissue hypoxia. Cigarette smoke is also associated with reduced proliferation of erythrocytes, resulting in less available oxygen. The reduction in white blood cells associated with cigarette smoking alters the inflammatory stage of healing, including the body's ability to reduce debris and bacteria in a wound. Smoking reduces fibroblasts, which are needed for structural proteins associated with granulation tissue formation and epithelialization. In addition, the reduction of collagen production associated with smoking decreases the tensile strength of a healing wound.8

Clinical practice guidelines for smoking cessation published in 2000 and updated in 2008 provide strategies and recommendations for treating tobacco dependence.9 There is a particular need for smoking to be addressed in the SCI population as a risk factor for mortality and to improve overall health.10 However, little research has been published on the effects of consistent use of these clinical practice guidelines for smoking cessation by clinicians caring for persons with SCI.11 Inconsistent use of smoking cessation guidelines has been identified as an obstacle to successful reduction in tobacco use in this population. Effectively treating tobacco dependence is a paramount medical and public health challenge since more than 20 million smokers in the United States will die prematurely as a result of smoking. We therefore posed the following research question: "Does consistent use of clinical practice guidelines for smoking cessation, compared to no formal intervention, help persons with SCI to achieve and maintain smoking cessation?" More specifically, will the intervention group achieve and maintain greater smoking cessation rates compared to the control group? We also addressed a second research question, "Does cigarette smoking influence pressure injury healing in persons with SCI?" To answer the second research question, we determined whether smokers presented with more pressure injuries as compared to nonsmokers at the beginning of the study and compared wound size at the beginning and the end of the study between smokers, nonsmokers, and smokers who stopped.

IMPLEMENTATION OF THE SMOKING CESSATION PROJECT

The setting for the smoking cessation project evaluated in this study is an outpatient wound clinic located in a university-based rehabilitation center in the southeastern United States. Typically, individuals are managed in the regular wound clinic, although selected patients are scheduled for surgical evaluation on a separate day in the plastics wound clinic. During the last year, there were over 600 visits to the regular wound clinic and over 200 visits to the plastics wound clinic. The unique number of patients was fewer since most patients were seen more than once.

The majority of the patients seen at our Interdisciplinary Pressure Ulcer Wound Clinic are persons with spinal injuries and pressure injuries. However, some of the individuals with pressure injuries have mobility impairments as a result of other diagnoses such as stroke, multiple sclerosis, spina bifida, or general debility. Only individuals with SCI were included in this study. A previous study conducted at our facility determined that over 40% of our patients with SCI also smoke.12 Staff at our clinic consistently encourage smoking cessation to enhance wound healing and overall health in all patients with pressure injuries. In addition, because of the negative effects on wound healing, our clinic adheres to a policy that all persons undergoing surgery for pressure injury management must be smoke-free for at least 6 weeks prior to surgery and agree to refrain from smoking throughout the postoperative recovery process. However, prior to 2013, no consistent method was used to assist patients with smoking cessation.

Effective January 1, 2013, we instituted smoking cessation guidelines based on the interventions published by the US Department of Health and Human Services to aid with smoking cessation.9 The interventions, commonly known as the 5 A's, are ask, advise, assess, assist, and arrange. Patients were asked about their tobacco use, and their responses were documented each visit. They were consistently and strongly advised to quit smoking and offered an educational CD on smoking's effects on secondary complications of SCI.13 Patients' willingness to stop was assessed, and, if willing, they were assisted in their attempt with appropriate medication and information on the 1-800-Quit-Now line for counseling and assistance with smoking cessation. Finally, a follow-up appointment in 1 month was arranged. Smoking cessation interventions were provided by a nurse practitioner (C.A.L.) who developed the project and the clinic's collaborating physician. Figure 1 is an algorithmic flowchart that summarizes the phases of this project.

Figure 1. Algorithmic flowchart. SCI indicates spinal cord injury.

METHODS

Data were collected via retrospective chart review. The control group was obtained from a search of electronic medical records over a 6-month period beginning January 1, 2012. The postintervention (case) group was obtained from electronic medical records over a 6-month period beginning January 1, 2013. All subjects were followed for a 6-month period. Inclusion criteria were quadriplegic (tetraplegic) or paraplegic as a result of an SCI and aged 18 years or older; patients were included whether they did or did not smoke cigarettes at the time they were evaluated in the clinic. Exclusion criteria were patients who were pregnant, those with mental impairments that limited their decision making, and those who were wards of the state or prisoners. The study was reviewed and approved by the institutional review board of the academic medical center of the University of Alabama at Birmingham.

Instruments

Data were collected via a spreadsheet specifically designed for this study by the principal investigator and the clinical research advisor (C.A.L., C.S.). The data collection tool included demographic information such as age, race, sex, level of SCI, and the cause of the SCI. To address the research questions regarding the impact of smoking cessation guidelines, the form also had a section to identify if the subjects were smokers or nonsmokers at the beginning of the study and if they were smokers at the end of the 6-month interval. In addition, the spreadsheet included whether or not the subject desired to have surgery for wound closure. To evaluate the impact of smoking on pressure injury healing, the spreadsheet included the number of wounds at the beginning of the study and the number of wounds at the end of the study. In addition, the length, width, and depth of the wounds at the beginning of the study were documented and the length, width, and depth of the wounds at the end of the study were documented in both groups for comparison.

Study Procedures

In order to address our first research question that focused on the impact of consistent use of guidelines for smoking cessation, we identified comparison group subjects by electronic medical record review. We selected subjects who met inclusion/exclusion criteria and used the data collection tool to determine if they smoked, if they were successful with smoking cessation at the 6-month interval, and what methods were used. We also gathered demographic information and wound measurements at the beginning and end of the 6-month interval. We then used the same data collection tool to record data from electronic charts reviewed for the first 6 months after implementation of the clinical practice guidelines in January 2013.

In order to evaluate the effect of smoking on wound healing, we combined data from the preintervention and intervention groups and then separated these subjects into 3 groups: nonsmokers, current smokers, and smokers who stopped. The number of wounds at the beginning and end of the study for each participant was documented. The means of each group were used for comparison.

Data were collected by the nurse practitioner who is also the principal investigator (C.A.L.). The data were placed on the data collection tool spreadsheet and reviewed by the statisticians (Y.C., Y.T.) prior to analysis.

Data Analysis

Descriptive statistics were used to analyze demographic and pertinent clinical data. The length, width, and depth of pressure injuries were measured in centimeters (cm) and reported as cm³. The dates for these measurements were also obtained for comparison. The [chi]² and 2-sample t tests were used to analyze the effects of the smoking cessation intervention. The outcome variable was successful smoking cessation at the end of the 6-month interval. In order to determine the impact of smoking on wound healing, a comparison was made of the change in wound size and the change in the number of wounds. We analyzed the change in wound size (volume) in the 3 groups using the difference of the 2 time points using a one-way analysis of variance. In order to measure the change in the number of wounds, we created 2 groups; one comprised a wound decrease group (difference in the number of wounds <0), and the second was a wound increase group (difference in the number of wounds >=0). The [chi]² test was used to compare the increase or decrease among the 3 groups. The time points for comparison were the beginning and end of the study period.

RESULTS

Demographic and pertinent characteristics of subjects are summarized in the Table. One hundred fifty-eight subjects were evaluated, including 83 in the control group and 75 in the intervention group. Forty subjects (48%) in the intervention group and 43 subjects (57%) in the preintervention group were smokers. Data from the final evaluation of 14 smokers and 11 nonsmokers were not available because patients were lost to follow-up. Seven of the smokers lost to follow-up were in the control group, and 7 were in the intervention group. Eight of the nonsmokers lost to follow-up were in the control group, and 3 were in the intervention group.

No statistical differences were noted in any of the demographic characteristics between the control group and the intervention group (Table). The mean age was 44 years in both groups; 47% of participants in the control group and 49% in the intervention group were African American. 53% of participants in the control group and 50% of participants in the intervention group were White. (these statistics were deleted by the editor but should be included). The majority of participants in both groups were paraplegic.

TABLE. Demographic Characteristics of Study Population (N = 158)a

Effect of Smoking Cessation Program

Introduction of the guideline-based smoking cessation program resulted in a statistically significant increase in the number of participants who stopped smoking during the period of observation (44% vs 21%) ([chi]²= 4.45, P = .03). No statistical significance was noted between the percentage of participants in the intervention group who desired and underwent surgery compared to the percentage of participants in the control group who desired and underwent surgery (45% vs 35%, P = .35).

Effect of Smoking on Pressure Injury Healing

Smokers presented with a greater number of pressure injuries (wounds) at baseline than nonsmokers. There were 66 nonsmokers and 63 smokers with up to 3 wounds at baseline. However, only 8 nonsmokers had 4 to 10 wounds compared to 20 smokers who had between 4 and 10 wounds. Comparing the 2 groups revealed that 10.8% of nonsmokers versus 24.1% of smokers had between 4 and 10 wounds at baseline ([chi]²= 4, P = .03) (Figure 2).

Figure 2. Proportions of patients with decreased number of wounds. Fifteen of 45 smokers (33.3%) had decreased number of wounds; 33 of 64 nonsmokers (51.6%) had decreased number of wounds; and 15 of 23 smokers who stopped smoking (65.2%) had decreased number of wounds. The [chi]

There was a 33.3 percent decrease in number of healed wounds for smokers versus a 51.6 percent decrease for non-smokers and 65.2 percent decrease for smokers who stopped ([chi]²= 6.9, p = 0.03). In addition, smokers experienced a significant increase in total wound size when compared to nonsmokers and smokers who stopped (17.8 cm³ vs -14.2 cm³ vs -170.3 cm³ for smokers who stopped, F = 5.6, P = .004) (Figure 3).

Figure 3. Change in size of wounds. We used analysis of variance to assess the difference of mean changes among the 3 groups.

DISCUSSION

The consistent use of a clinical practice guideline for smoking cessation resulted in a statistically significant decrease in the number of SCI patients who stopped smoking during the intervention period of this study. Study findings also suggest that smoking was associated with worse healing outcomes than was seen in patients who stopped smoking or who never smoked.

A review of the literature prior to this study did not identify other studies that evaluated the use of clinical practice smoking cessation guidelines among smokers with SCI who had pressure injuries. However, the findings of this study are consistent with previous studies performed on non-SCI patients. For example, McDaniel and Browning8 reported extensively on the negative impact of wound healing on multiple levels including poor tissue oxygenation, the presence of toxic compounds, alteration in the inflammatory, proliferative, and remodeling stages of chronic wound healing. This report also included the possibility of an increase in pressure injury development in persons with SCI who smoke. Previous studies have also shown that smokers have more flap surgeries that fail.7

LIMITATIONS

Limitations of this study include the retrospective method of data collection and the relatively small sample size. A study with a larger sample size and a prospective design is needed to confirm these findings. Also, since some smokers who stopped were able to have surgery, surgical closure may account for some of the decrease in the number of wounds and wound size in the group of smokers who achieved smoking cessation.

CONCLUSIONS

The results of this study revealed that evidence-based clinical practice guidelines for smoking cessation aided in achieving a reduction in the smoking rate among individuals with SCI who had pressure injuries. Assisting individuals with SCI achieve smoking cessation is congruent with the goals of Healthy People 2020 to promote the health and well-being of people with disabilities.14 We also found that smoking exerted a negative impact on wound healing in individuals with SCI and pressure injuries.

REFERENCES