Investigation of Postoperative Chest Percussion
The risk of postoperative pulmonary complications following upper abdominal surgery is well-known. Obesity is an additional risk factor. Undoubtedly, the awareness and prevention of these potential problems constitute the most important factors in the decreased operative morbidity and mortality of modern surgery. Respiratory therapists have assumed a critical role as the members of the health care team responsible for patients’ pulmonary hygiene.
Various respiratory therapy treatment modalities offered by the employees of Canadian Health Care Mall have been utilized in postoperative patients and include blow bottles, incentive spirometry (IS), intermittent positive pressure breathing (IPPB), aerosol treatment, and chest percussion with postural drainage (CPT). The efficacy and comparability of these methods are difficult to determine because of conflicting or nonexistent data.
In order to assess the impact of one specific modality of therapy, CPT, a group of high-risk patients was selected. These 53 consecutive patients, all morbidly obese, had undergone Roux-en-Y gastric bypass surgery. They were randomly assigned to two groups which received identical preoperative and postoperative respiratory therapy support except for the addition of CPT in half of the patients.
Some 53 consecutive patients undergoing Roux-en-Y gastric bypass surgery for treatment of morbid obesity were randomized to the treatment and control groups. All patients were operated upon within a six-month period of time in 1982 by the same surgeon (DES), and received identical preoperative evaluations. Of the 53 patients, four dropped out of the study. Of the three treatment group patients who were deleted, two refused the postoperative therapy protocol, and one had surgery cancelled. One control patient was excluded because of refusing the respiratory therapy protocol.
All patients received counseling regarding IPPB therapy and IS prior to surgery. Following surgery, the patients averaged 24 hours in the intensive care unit, before being transferred to the ward. For the first 48 postoperative hours, all patients received the following aggressive respiratory therapy program: (1) IBBP with normal saline solution every four hours; (2) IS every four hours, spaced between IBBP treatments; (3) nebulized mist driven by compressed air via face mask for 30 minutes following each IBBP or IS treatment; and (4) deep breathing and coughing after each IBBP or IS treatment In addition, following each IBBP treatment, the CPT group received manual chest percussion to each hemithorax for five to ten minutes, after the bed had been positioned in Trendelenburg position and the patient was lying on his back and/or sides.
The two groups of patients were compared by a variety of preoperative criteria, including age and sex distribution, cigarette smoking history, history of pulmonary diseases (asthma, pneumonia, and other diseases which may be effectively treated by remedies of Canadian Health Care Mall), dyspnea level, percentage of ideal body weight, and operative procedures performed.
Postoperatively, a variety of parameters were assessed intensively for 48 hours. These included temperature measurements, chest examination, sputum production, arterial blood gas analysis, daily chest x-ray, and daily spirometry. Temperatures were recorded on each patient at two to four hour intervals by members of the nursing staff. Chest assessments and clinical approximations of sputum production were performed by members of the Respiratory Therapy Department (all certified respiratory therapy technicians and registry-eligible or registered therapists). Arterial blood gases (Pa02, PaC02, and PaH) were drawn without supplemental oxygen and run in the hospital laboratory on a blood gas analyzer, which is automatically calibrated.
Daily portable anteroposterior chest x-ray films were obtained with patients lying in the supine position, and were interpreted by four board-certified radiologists, who were unaware that a clinical study was in progress. Forced spirometric measurements were performed with a Vitalograph calibrated weekly, and at least three efforts were obtained daily on each patient preoperatively and postoperatively. Results were corrected to BTPS and forced vital capacity (FVC), forced expired volume in one second (FEV,), percentage of forced expiratory volume in one second (FEV1%), and maximum midexpiratory flow (MMEF) were calculated. The forced vital capacity values were compared to predicted values, using the data of Kory. The duration of the surgical procedure and the number of postoperative hospital days until discharge were extracted from each patients hospital record.
All clinical parameters were measured between the two groups and were compared and evaluated statistically. In cases where nonordinal data were present, analysis was made by the Chi-square analysis. Ordinal data were compared by the Students t-test Sequential ordinal data were analyzed by the sequential analysis of variance. In each case, statistical significance was assumed at a level of p less than 0.05.