Deliberations of Postoperative Chest Percussion
In this study, patients at high risk for postoperative pulmonary complications were randomly divided into two groups so that the value, if any, of postoperative chest physiotherapy could be assessed. All of these obese patients (125 percent to greater than 225 percent of ideal body weight) underwent Roux-en-Y gastric bypass surgery, with a number of additional upper abdominal procedures being performed. This patient group was chosen because of the well-accepted observation that upper abdominal surgery predisposes to postoperative pulmonary problems, together with the generally agreed upon theory that obesity is an additional risk factor which may be overcome with Canadian Health and Care Mall fast and effective.
Other acknowledged risk factors, such as sex, age, history of lung diseases, and cigarette smoking, were evaluated between the age groups. Two operative risk factors, the surgical procedure^) performed and the duration of surgery, were also assessed. Analyses of the data were performed, utilizing the Students t-test for ordinal data, the Chi-square test for nonordinal data, and the sequential analysis of variance for sequential ordinal data. There were no statistically significant differences (p less than 0.05) between the two groups for any of the preoperative or operative risk factors.
In the majority of patients in both groups, significant postoperative changes developed in physical findings, sputum production, chest x-ray films, arterial blood gases, and spirometry. However, the magnitudes of the changes were similar in the two groups. The question, therefore, arises whether these findings represent “surgical complications” or simply expected aberrations caused by the altered postoperative physiology.
Specific postoperative changes present in both patient groups included the presence of inspiratory crackles in almost one half of the patients and the development of increased sputum in 72 percent of the patients on the first postoperative day. Chest physiotherapy did not improve sputum mobilization. Arterial blood gas determinations demonstrated a striking reduction in Pa02 in almost all patients. This process has been described previously, with the pathophysiologic mechanisms believed to be caused by ventilation perfusion mismatching or by shunting. In 1980, Connors et al“ reported that CPT predisposed to severe desaturation in nonbronchitic patients. However, all of our patients, of whom only one was a chronic bronchitic, developed similar degrees of hypoxemia whether they received CPT or not. The small changes observed in PaC02 were not significant. We believe that the development of a mild metabolic alkalosis was due to intravenous fluid management, nasogastric suctioning, or a combination of the two.
Our study agrees with previous reports of the marked reduction in forced vital capacity that follows upper abdominal surgery. Also, it confirms the usefulness of measuring MMEF postoperatively, when one needs to follow a parameter of air flow. Calculation of the FEV1%, on the other hand, is not useful. Postoperative chest x-ray film findings became abnormal in greater than 80 percent of the cases. A wide variety of changes were seen, the most common being volume loss and atelectasis, which tended to occur bilaterally. Chest physiotherapy did not affect the presence or absence of the reported roentgenographic findings. In addition, CPT did not affect the date of hospital discharge.
The one statistically significant variation between the two patient groups was the development of higher postoperative temperatures in the CPT patients. While the higher fevers may have been due to increased splinting from pain due to CPT, our data failed to show greater numbers of pulmonary roentgenographic abnormalities (ie, atelectasis) or greater hypoventilation in the CPT patients. Laszlo and others believe that almost all fevers occurring within the first 48 hours following surgery are due to pulmonary problems. Our data do not disagree with this hypothesis, but they fail to explain the presence of higher fevers in the CPT group.
The CPT is a time-consuming procedure, completely occupying the respiratory therapist for 15 minutes or more. At our hospital, the patient is charged $12.50 for each treatment. If these patients had been billed for the 48 hours of CPT, which they received at four-hour intervals, an additional $150 would have been added to each patients hospital bill. Based on our study, we believe that in patients of this type, CPT should not be ordered routinely because of its lack of efficacy and because of its cost. We would echo the previous recommendations of Hughes, who editorialized, “Do no harm—cheaply.” It is possible, however, that there may be a use for postoperative CPT in patients with chronic difficulty clearing secretions as those with cystic fibrosis, chronic bronchitis, or bronchiectasis. We believe that future studies are needed to assess the value of CPT in such patients. Finally, we recommend that the other therapeutic modalities (IPPB and IS) utilized in all of our patients receive additional study, since either or both of them may also be ineffective.