Evidence-based Practice Interventions for Reducing Postoperative Pulmonary Complications: A Narrative Review

4. INCENTIVE SPIROMETER (IS) AND PREOPERA-TIVE IS EDUCATION

According to Guimaraes [9], physiotherapy can increase unusually low postoperative functional residual capacity by improving inspiration. IS is an example of physiotherapy, which has been regularly considered a part of the preoperative prophylactic respiratory therapy bundle that aims to prevent and/or treat PPCs. The IS device assists and allows patients to take deep and slow breaths, which increases lung inflation and ultimately promotes optimum gas exchange and adequate lung expansion. As patients establish a routine to continue to use this device at least ten times an hour, it is effective in deterring the development of PPCs [10]. According to Berman et al. [11], by using the IS at the time of inhalation, the flow of air can be measured by the mouthpiece and can assist with overcoming the effects of anesthesia and loosening secretions, which allows for better gas exchange and ventilation. The studies also say that the IS is easy to use and gives patients visual feedback, promoting concordance. In addition, patients can independently use the IS once they are trained. It also provides an effective inspiratory effort and is inexpensive [12]. About 95% of hospitals in the US utilize the IS as a prophylactic measure in patients during both the preoperative and the postoperative period [13].

An experimental study carried out by Khanna [10] tested the efficacy of the use of the IS in postoperative patients who had undergone abdominal or thoracic surgery. This study concluded that using the IS during the preoperative period improves pulmonary function postoperatively. The results showed a marked reduction in the pulmonary function variables of peak expiratory flow rate (PEFR), forced expiratory volume (FEV)1, and FEV6, which were present after surgery. Furthermore, after three and five days postoperatively, IS group patients had superior pulmonary functions when compared to the group carrying out deep-breathing exercises. In addition, the results of these studies were consistent with previous research conducted by Kundra, Vitheeswaran, Nagappa, & Sistla [14], which also concluded that IS is effective in improving postoperative pulmonary complications in abdominal surgery patients. Moreover, this present study also implied compliance was critical for patients in the experimental group, and supervision could be beneficial to ensure an accurate technique and routine use.

As indicated, preventive measures for PPCs should be applied from admission and continued throughout the patient's clinical course. Patients and families should be educated on the potential for postoperative lung complications, the correct use of the IS, and the proper way to breathe deeply and cough. Education during the preoperative period is more effective than when patients are in pain or groggy from sedation during the postoperative period. Patients should be educated on how valuable the IS is and be encouraged to use it at least every 2 hours while awake. Education should be made based on patient preferences. When care providers do not take the time to thoroughly educate patients on the importance of using the IS or watch for a good return demonstration by the patient, the patient ends up with a plastic decoration at their bedside table. Patients need to be encouraged to use it. They must know how to do it correctly: good effort, positioning, frequency, repetition, and coughing. This will achieve the full effect of the IS, such as oxygen saturation and lung expansion, and will prevent the development of basilar crackles.

A randomized study conducted by Bergin et al. [15] on the effect of preoperative IS education (POISE) with a total of 140 participants included instructions for the use of the IS device during the preoperative period (in some cases at home) and the postoperative period. The non-intervention group recorded their postoperative volumes, which were used to determine their baseline volumes. This study's findings revealed that despite no significant difference in the return to baseline volumes between the two groups, the intervention group (POISE) did demonstrate a decrease in the length of hospital stay, postoperative complications, and cost and care. In addition, POISE patients ranked the intervention as helpful and had better outcomes. Preoperative education on IS enhances its postoperative use and reduces patients' complications. Another study conducted by Kundra et al. [14] specifically compared the use of the IS during pre- and postoperative periods in patients undergoing laparoscopic cholecystectomy. This study concluded that lung functions were significantly reduced until discharge in both groups. Still, the overall lung functions were better preserved with the preoperative use of the IS compared to its postoperative use. Additionally, this study pointed out that a lack of efficacy of the IS in previous studies could be due to poor patient compliance. The study by Kundra et al. (14) recommended the prophylactic use of the IS to build up patients' pulmonary reserves as the patients are more motivated and in better physical condition to perform and be carried out under supervision.

In contrast, a search utilizing the Cochrane database for incentive spirometry revealed two relevant meta-analyses, one for upper abdominal surgery and another for pulmonary complications after a coronary artery bypass graft (CABG). Nascimento et al. [16] looked at 12 different studies involving more than 1800 patients and found no apparent benefit of the IS, although they deemed the overall power of the studies to be “low.” The CABG article analyzed seven RCTs and 592 patients; the authors reported that as the quality of evidence is insufficient and unreliable with regards to the effectiveness of the IS in the prevention of PPCs post-CABG, it cannot be concluded whether or not the IS is truly effective. The author also pointed out that most studies had a small number of participants and did not identify substantial variations in the outcome measurements between groups. A systematic review conducted by Rupp, Miley, and Russell-Babin [17] was also evaluated. This study included four systematic reviews and one clinical practice guideline. It concluded that prophylactic use of the IS has not proved more effective than deep breathing or any other single prophylactic technique.

Kokotovic et al. [18] conducted a systematic review and meta-analyses in 2021. They aimed to evaluate the advantages of pulmonary interventions and mobilization postoperatively after abdominal surgery compared with standard protocols to decrease adverse events. Even though the use of postoperative expiratory resistance modalities like continuous positive airway pressure (CPAP), Expiratory Positive Airway Pressure (EPAP), bi-level positive airway pressure (BiPAP), Non-invasive ventilation (NIV) after abdominal surgery might prevent pulmonary complications, there is a need for more data and research to assess the existing evidence. Meta-analyses revealed that compared to standard care, management with high expiratory resistance (CPAP, EPAP, BiPAP, NIV) decreased the chances of respiratory problems. However, they were not able to reach the necessary information size in the sequential trial study.

5. EARLY MOBILIZATION

Changing position (i.e ., getting into a chair) is advantageous physically and mentally. It should be noted that patients usually have improved lung compliance and the ability to manage respiratory secretions when seated. Also, if patients are always lying down, they tend to feel lightheaded and dizzy when they do get up because of an instant drop in blood pressure. An additional benefit is the strengthening of muscles. The chances of developing acid reflux and breakdown of skin are also decreased when patients are in a seated position. Also, psychologically, the patient will feel better and more alert when not lying in bed 24/7. A systematic research study revealed that several randomized controlled studies had been done to evaluate the effectiveness of deep breathing exercises in postoperative patients. For instance, a randomized controlled study by Silva, Li, and Rickard [19] compared the effects of early and delayed mobilization in postoperative patients. The study concluded that patient mobility, if not started at an early stage, led to increased physiotherapy involvement. However, no substantial difference in the reduction of PPCs between the two groups. In contrast, Haines, Skinner, Berney, and Austin Health POST Study Investigators [20] conducted an observational cohort study examining the association of PPCs with delayed mobilization in postoperative patients. The study revealed a link to an increased incidence of PPC when patients are not mobilized soon after surgery.

6. TURN COUGH/DEEP BREATHING

To reduce the risk of pulmonary complications like pneumonia, breathing exercises that increase the effort of inspiration are most useful, as in the study by Silva, Li, and Rickard [19]. They can be useful in postoperative patients with rapid breathing and cough hesitancy. Inactivity and bed rest can lead to volume overload, causing hypostatic pneumonia. However, this adversity can be prevented by directing coughing and deep breathing exercises. Additionally, patients under heavy sedation do not breathe as deeply as they should, leading to pulmonary stasis and infection due to hypoventilation. The correct technique for coughing and deep breathing encourages lung inflation/expansion, opening the airways and moving static secretions, thereby potentially reversing the effects of pulmonary fluid accumulation and avoiding stasis and infection. Postoperative patients who are in pain should be educated on the techniques that will help them, and the importance of early deep breathing exercises should be emphasized; they should be shown how to splint the wound to ease the pain when coughing. Pending more research, recommendations are for deep breathing and coughing postoperatively to decrease the risk of complications. Still, there is insufficient evidence to associate that with reducing postoperative fever. However, an experimental study conducted by Nandi et al. [21] compared the effectiveness of the IS versus deep breathing exercises in post-abdominal surgery patients. The results of this study measured the improvement in PEFR over five days. The study concluded that the PEFR was significantly higher among the experimental group compared to the control, thus indicating that IS was more effective than deep breathing.

Arguably, it is important to keep in mind that there were limitations to this study, such as a small sample size, only one outcome measure (PEFR), and the inclusion of abdominal/thoracic surgery patients. We need more research with a bigger sample size to drive practice change. A randomized control study by Lunardi et al. [22] also concluded that deep breathing exercises were ineffective in preventing PPCs. Patients who did deep breathing exercises after abdominal surgery had a higher incidence of PPC compared to the IS group.

7. CHEST PHYSIOTHERAPY

In terms of literature evidence on chest physiotherapy, a randomized controlled study conducted by Gbiri, Ajepe, and Akinbo [23] compared the efficacy of IS and chest physiotherapy in 90 patients who had had thoracic/abdominal surgery. A random selection of patients was made, and they were divided into three groups with 30 patients each. All groups received early mobilization. Group 1 was also given selected chest physiotherapy, Group 2 was assigned ISs, and Group 3 was given a combination. All groups had their cardiovascular and pulmonary function checked 24 hours before surgery and during the postoperative period at 24 hours, the third day, and the seventh day. In addition, patients had their blood pressure, mean arterial pressure, pulse pressures, and oxygen hemoglobin saturation monitored for the cardiovascular function check. For the pulmonary function check, patients had forced vital capacity and forced expiratory volume in one second (FEV1) monitored. The results indicated that all clients were 100% compliant with the therapy. Among the experimental groups, there was a significant reduction in cardiovascular and pulmonary complications between 24 hours pre-operatively and 24 hours postoperatively. The study also concluded that chest physiotherapy and the IS were ineffective in reducing postoperative complications, but the combination of these two was clinically more effective. However, participants who received both had a much-improved clinical course and no complications.

Another randomized placebo-controlled superiority trial was conducted by Boden I, et al. [24]. They concluded that a 30-minute physiotherapy session preoperatively in patients scheduled for elective upper abdominal surgery could reduce the risk of developing PPCs and hospital-acquired pneumonia. However, they did mention that more research is required to evaluate the benefits to duration of stay and overall prognosis.

8. INSPIRATORY MUSCLE TRAINING

A randomized controlled study by Savci et al. [25] monitored the efficiency of IMT on postoperative CABG surgery patients. For measurements, both groups had their pulmonary function tests (PFTs), 6-minute walk tests (6MWTs), quality of life, and psychosocial status assessed pre-operatively and five days postoperatively. Experimental group patients showed a substantial improvement in inspiratory muscle strength five days postoperatively. This group demonstrated walking a further distance during the 6MWT, improved quality of life as indicated by better sleep quality, a lower anxiety score reflecting better psychosocial status, and—most importantly—a significantly decreased length of stay in the hospital compared to the control group. The conclusion was that IMT positively increased patients' overall pulmonary function post-CABG, resulting in improved and efficient recovery of respiratory muscle strength, functional capacity, short hospital stays, quality of life, and psychosocial status.

In addition, Casali, Pereira, Martinez, de Souza, and Gastaldi [26] conducted a randomized controlled study that analyzed the efficacy of IMT in bariatric surgery patients. They particularly assessed the effects of IMT on PFTs, strength of muscles involved in respiration, and stamina. Their findings concluded that IMT led to an improvement in the strength of inspiratory muscles and stamina. In morbidly obese patients, it also helps with faster recovery of airflows in the respiratory system. Similar studies by Barbalho-Moulim, Miguel, Forti, Campos, and Costa [27], Dettling et al. [28], and Dronkers et al. [29] also concluded that IMT is effective in improving lung expansion. In another study by Valkenet et al. [30], outcomes were similar. They concluded that preoperative exercise therapy with inspiratory muscle training or exercise training before abdominal or cardiac surgeries was associated with reduced hospital length of stay and postoperative complication rates.

Even though numerous studies have confirmed the effectiveness of IMT in reducing PPCs, other studies conclude the opposite. For instance, Kulkarni, Fletcher, McConnell, Poskitt, and Whyman [31] conducted an RCT to assess preoperative IMT on respiratory variables in patients undergoing major abdominal surgery. This study's results indicated no significant reduction in postoperative MIP in the experimental groups concluding that IMT is ineffective in reducing PPCs.

Additionally, a randomized controlled trial was conducted by Lunardi et al. [22] to compare the lung expansion techniques, such as flow IS, deep breathing and volume IS, and their effect on pulmonary volumes, respiratory muscle activation, and the incidence of PPCs in postoperative abdominal surgery patients. Outcomes were collected over a span of 5 days. Results indicated no significant difference in lung volumes and inspiratory muscle activation during lung expansion techniques. Therefore, the authors concluded that the techniques do not prevent PPCs in postoperative abdominal surgery patients. However, they also suggested that more studies must be conducted to confirm their findings and change the standard practice.

Another systematic review by Mans et al. [32] showed that the risk of pulmonary complications can be reduced by half with preoperative IMT. It can lead to the improvement of respiratory muscle function. It should be noted that it did not increase the duration of hospital stay. Going forward, we need more data to ascertain if it decreases the length of stay [32]

9. SYNTHESIS OF EVIDENCE

The purpose of this evidence review was to evaluate the effectiveness of each intervention listed above in preventing PPCs. Despite differences in the characteristics of participants and the interventions, it is determined that there is a lack of conclusive evidence to support the effectiveness of a single intervention that would promote lung expansion, thereby reducing and/or preventing PPCs. The main findings indicate that there is mixed research surrounding the use of incentive spirometry and the use of a single prophylactic technique in preventing PPCs in postoperative patients. For instance, some studies state that IS is not recommended alone to prevent postoperative pulmonary complications; IS used with directed coughing, deep breathing techniques, and early mobilization is recommended to avoid PPCs.

Hence, the question is, why do clinicians use them in hospitals? There is no sufficient evidence to say they provide no benefit definitively, so we still use them, but we should have a good understanding of what actual benefit each intervention provides, which may not be much in the case of the IS. While it may “seem like” it does a lot, the whole purpose of obtaining reliable evidence is that what “seems like” it works often does nothing in reality. Arguably, RCTs with a small sample size in a single patient population in a Third World country should not drive changes in practice. Only literature reviews and, preferably, meta-analyses should be used to support the use of ISs. For instance, one of the studies reviewed in the study by Nascimento et al. [16] was limited to 150 patients in an African Hospital in Lilongwe, Malawi. IS was not recommended due to the constrained resource environment. The mortality was 6% in the control group despite early ambulation, coughing, and deep breathing techniques. This is not conclusive evidence, but it is useful information for working in Third World countries. Additionally, it will be challenging to convince a clinician that routinely expanding your lungs while in the healing process is not beneficial.

Research has shown that implementing a respiratory bundle managed by nurses primarily was successful. A study by Mola et al. [33] showed that increasing the use of less invasive respiratory support, such as respiratory bundles, in low birth-weight infants was beneficial. Patients showed significant improvement in oxygenation both immediately after and 15 minutes after breathing exercises were performed in the standing position compared to the sitting position. Even though these interventions are inexpensive and easily promoted, they are a waste of resources if ineffective in improving patient outcomes.

Nonetheless, the cumulative effect of interventions seems optimistic, but more studies need to be conducted. In all studies, the participants ranked education to be an effective intervention. Based on the evidence reviewed for each intervention listed above, research supports a combination of techniques to achieve positive surgical outcomes, as they have a clinically efficacious effect. Postoperatively, it is important to encourage early ambulation soon after surgery to promote lung compliance. Improving blood flow will also help prevent other complications like venous thromboembolism.

Moreover, after a thorough review of the practice and evidence, it seems that applying all interventions as a pulmonary bundle would be more beneficial. To support this further, an observational study conducted by Cassidy, Rosenkranz, McCabe, Rosen, and McAneny [34] examined the efficacy of a multidisciplinary patient care program in reducing PPCs. As a part of this study, Dr. Cassidy and her colleagues designed a program called ICOUGH, which is a multidisciplinary pulmonary care program. It consists of detailed education for patients and caregivers, uniform healthcare provider orders for early ambulation during the postoperative period, and respiratory care. The acronym ICOUGH translates to IS, coughing and deep breathing, oral care (includes brushing teeth and mouthwash use twice a day), understanding (emphasizing patient and caregiver education), getting out of bed (recommend at least three times a day), and head of the bed elevation. To test the efficacy of this program, the team reviewed the respiratory outcomes before and after the National Surgical Quality Improvement Program (NSQIP) program completion. This program was piloted at Boston University Medical Center and used for general and vascular surgery patients. The program's results were monitored over one year and indicated that the incidence of postoperative pneumonia fell from 2.6% before the implementation of ICOUGH to 1.6% post-ICOUGH program implantation. In addition, the results also showed that after the implementation of ICOUGH, the institution rate of unplanned intubation also decreased, from 2.0% to 1.2%. Thus, if ICOUGH was made a standard practice of care, it could reduce the incidence of postoperative pneumonia and unplanned intubation, saving healthcare organizations a lot of money in the long run.

A similar multicenter observational study was conducted by Jin et al. [35]. It evaluated the occurrence and risk factors associated with developing PPCs in non-cardiac postoperative Chinese patients. It was conducted over six days at four university hospitals and enrolled 1673 participants. Patients were grouped into two different cohorts. Cohort I developed a predictive risk index for PPCs, and Cohort II validated the index. The results showed that 163 (9.7%) patients developed PPCs associated with a more extended hospital stay. The mortality rate among these patients was 1.84%. Cohort I had nine independent risk factors, including tobacco use, pulmonary infection in the last month, use of antibiotics preoperatively, peripheral oxygen saturation preoperatively, surgical site, amount of blood lost, postoperative blood glucose level, albumin level, and ventilation. Cohort II validated these factors. In conclusion, this study successfully developed a risk predictor index for non-cardiac surgery patients. This index can be used as a guide and can estimate the risk of developing PPCs; based on the score, an individualistic respiratory plan can be designed during the perioperative period.

Another study by Wren et al. [36] states that pneumonia is the third most common complication postoperatively. This study also said that having a standardized program has reduced postoperative pneumonia by 40%. If other hospitals adopt this model, it could potentially save $280 million dollars in healthcare costs annually. A CNL, in collaboration with other team members creating a multidisciplinary approach, can pilot a similar program and determine its efficacy by comparing pre- and post-trial results for PPCs.

A number of studies noted there were constraints and limitations to their studies, such as a small number of participants, a lack of diversity, being localized to one area or institution, and needing more variables. For instance, the risk factors for each patient might differ, placing them at a higher risk of developing PPC and thus showing no significant difference in the treatment. In addition, the variation in experimental conditions might not be the same as the subject's daily routine, which can potentially influence and alter the effectiveness of the outcome. With many RCTs with a small sample size (between 20 and 150), it is challenging for the researcher to extract good-quality evidence and make reliable conclusions or statements about the studies. Moreover, factors such as geographic location and the cultural and social diversity of patients involved in the study make it difficult to develop conclusions pertaining to a particular group of individuals or a population. In addition, many studies were methodologically flawed, and the results were differing and not consistent. Out of all the studies reviewed, just two of them clearly explained the process of randomization. Finally, a few studies were performed over seven days or more. Thus, it is possible that a number of environmental and/or extraneous elements may have affected the results throughout this prolonged period.

Understanding the costs and benefits associated with these interventions is crucial for healthcare providers, policymakers, and patients in order to make informed decisions. There are direct and indirect costs associated with postoperative pulmonary complications Direct costs include healthcare expenses such as extended hospital stays, equipment costs, additional training of staff and additional treatments including medications. While indirect costs involve lost productivity due to long recovery times or subsequent disability and the need to maintain updated operating procedures to account for these interventions.

As we have discussed, the use of an incentive spirometer, early mobilization, directed coughing, deep breathing exercises, chest physiotherapy, and inspiratory muscle training (IMT) can lead to improved patient outcomes, shorter hospital stays, and a lower likelihood of long-term complications. Some of these interventions already exist as a part of the post-operative hospital care set for certain patient populations and would, therefore add bias to any cost analyses done that include them. These benefits are significant for patient improvement and satisfaction, even if they don't translate into cost savings. Going forward, detailed cost-effectiveness studies on specific interventions or examining the long-term economic impact of these interventions are needed.