European Journal of Cardio-thoracic Surgery 12 (1997) 72 729 Evaluation of routine postoperative chest X-rays in the management of the cardiac surgical patient 1 Podila Sita Rama Rao *, Qamar Abid, Khalid J. Khan, Robert J.R. Meikle, Krishnan M. Natarajan, Graham N. Morritt, John Wallis, Simon W.H. Kendall Cardiothoracic Surgery and Cardiothoracic Anaesthesia, South Cle eland Hospital, Marton Road, Middlesbrough, Cle eland TS 3BW, UK Abstract Received 9 October 1996; received in revised form 8 April 1997; accepted 8 April 1997 Objectives: To evaluate the role of routine chest X-rays in the management of patients post cardiac surgery. Methods: 30 adult patients undergoing cardiac surgery were studied in three consecutive groups (A, B, C) of 100 patients each. Forty patients were excluded due to the intensive care stay greater than 36 h (n=35), or early mortality within 36 h (n=5). Chest X-rays were performed according to three different protocols. in Groups A and B. In group C there were no routine chest X-rays during the entire postoperative period. In all three groups chest X-rays were performed where clinically indicated. Group A had three routine chest X-rays post-operation. Group B had one routine chest X-ray on day post-operation. Group C had chest X-rays only when indicated. The X-rays were evaluated in terms of their assistance value and the resultant number of interventions. Results: The three groups were similar preoperatively for age, sex, preoperative left ventricular function, presence of chronic obstructive airway disease and type of operation performed. The total number of chest X-rays in groups A, B and C were 30, 133 and 36, respectively. The number of chest X-rays leading to interventions were five, four and four in groups A, B and C, respectively. Chest X-rays that helped in management were 36, 28, and 28, respectively, in the same groups. There was no mortality or morbidity attributable to non-performance of routine chest X-ray. Conclusions: Routine chest X-rays post-cardiac surgery are of very little value and patients are adequately managed by performing chest X-rays only when clinically indicated. There was no increased mortality or morbidity attributed to lack of routine chest X-rays in any of these groups. We recommend performing chest X-rays only when clinically indicated in satisfactorily recovering adult cardiac surgical patients. 1997 Elsevier Science B.V. Keywords: Chest X-ray; Adult cardiac surgery 1. Introduction It is a standard practice in most cardiac surgical centres in the world to perform chest X-rays routinely three or more times post-surgery, based on protocol. This practice involves extensive use of resources and expenditure. Several authors have questioned the value of these routine chest X-rays [ 8]. * Corresponding author. Tel.: + 162 85892; fax: + 162 85613. 1 Presented at the Tenth Annual Meeting of the European Association for Cardio-thoracic Surgery, Prague, Czech Republic, October 6 9th, 1996. Stevens et al. [6], Hornick et al. [5] and Silverstein et al. [7] have concluded that the routine immediate postoperative chest X-rays in the intensive care are of limited value. Chong et al. [], from John Radcliffe Hospital at Oxford, have discussed the ways of simplifying management of cardiac surgical patients in general and this includes avoiding routine immediate postoperative chest X-rays in the intensive care unit and performing one only when indicated. However, these authors have only evaluated the role of routine chest X-rays in the intensive care unit in the immediate postoperative period only. in the intensive care and they all have concluded that chest X-rays are not useful in the absence of a clinical indication. 1010-790/97/$17.00 1997 Elsevier Science B.V. All rights reserved. PII S1010-790(97)00132-2
P.S.R. Rao et al. / European Journal of Cardio-thoracic Surgery 12 (1997) 72 729 725 Table 1 Protocol for performing postoperative chest X-rays Group A (n=100) Group B (n=100) Group C (n=100) Routine X-rays Clinically indicated X-rays Immediate No routine X-rays Day 1 Day 2 Day Yes Yes Yes However, there are no data regarding the role of routine chest X-rays performed subsequently in the high dependency unit, the ward and in the X-ray department. These are usually performed according to protocols resulting in continuous routine investigation of the patients during their hospital stay. We have therefore decided to conduct a clinical study in our adult cardiac surgical practice to evaluate the role of all routine chest X-rays performed postoperatively. in intensive care, the high dependency unit and finally in the ward. The main objective was to evaluate the contribution of routine postoperative chest X-ray in the management of adult cardiac surgical patients who are recovering satisfactorily. 2. Methods A total of 30 patients were studied postoperatively. Thirty-five patients whose intensive care stay was prolonged more than 36 h, and five patients who suffered early mortality within 36 h, were excluded from the study as their intensive care potentially required frequent investigation including repeated chest X-rays. Three consecutive groups of 100 patients each were studied with varying protocols for the timing and frequency of routine chest X-rays. Group A had routine chest X-rays immediately on return to intensive care, on the first postoperative day after removal of the chest drains and on the second postoperative day in the ward. Group B had routine chest X-ray on the fourth postoperative day only, usually performed in the Radiology department. This is similar to the routine pre-discharge chest X-ray performed in many centres. Chest X-rays were also performed in both Groups A and B whenever clinically indicated. In Group C no routine chest X-rays were performed in the entire postoperative period. Only indicated Chest X-rays were performed in this group only when indicated (see Table 1). Data collection included age, sex, operation, preoperative left ventricular function, hospital stay, and chronic obstructive airways disease as noted from the medical records. A separate proforma was filled in with each X-ray request detailing the clinical indication for the X-ray and any resultant change in management. The results were then analysed to evaluate (a) the chest X-rays that directly led to an intervention, and (b) those chest X-rays which assisted in the management of the patients. 2.1. Definitions 2.1.1. Indicated chest X-rays These are the chest X-rays which were requested on the basis of a clinical indication. The indications include postoperative (a) unsatisfactory arterial blood gases, (b) haemodynamic instability, (c) shortness of breath, (d) low oximetric saturations, (e) postoperative bleeding and (f) check X-rays following procedures such as the insertion of central venous lines and chest drains. 2.1.2. Routine X-rays Those chest X-rays which were done routinely at a preset time and date as per some protocol or postoperative follow-up plan. 2.1.3. Inter entions Interventions resultant directly from the abnormality displayed on chest X-ray. Those X-rays with findings that directly led to interventions in the patient management. Examples of these include procedures such as the insertion of chest drain for pneumothorax or pleural collection. 2.1.. Assistance Those X-rays with findings that helped in the patient management were included in this group. They influenced a change in medical management such as addition of diuretics or antibiotics, institution of chest physiotherapy or assessment of a resolving lobar collapse, consolidation, pneumothorax or pleural collection and chest X-rays to check central venous lines. 3. Results Thirty-five patients who stayed in intensive care unit longer than 36 h and five patients who had mortality within 36 h after surgery were excluded from the study (Table 2).
726 P.S.R. Rao et al. / European Journal of Cardio-thoracic Surgery 12 (1997) 72 729 Table 2 Group data Group A Group B Group C Mean age, years (S.D.) 61 ( 10) 61 ( 9) 63 ( 9) Male (%) 67 67 69 Mean LV EF (S.D.) 60 ( 1) 59 ( 1) 62 ( 1) CABG (%) 80 88 90 COAD (%) 8 9 3 Hospital stay, days 6.1 1.6 6.1 1. 5.9 1.5 (mean) LV EF, Left ventricular ejection fraction; CABG, coronary artery bypass grafting; COAD, chronic obstructive airway disease. The three groups of patients matched well in relation to age, sex, preoperative left ventricular ejection fraction, operation and hospital stay. Chronic obstructive airway disease was noted in 8 patients in group A, 9 in group B and 3 in group C (Table 3 and Table ). 3.1. Group A: three routine chest X-rays; immediate postoperation, day 1 and day 2 In group A, a total of 30 chest X-rays were performed. These included 296 routine and eight indicated X-rays. Four indicated chest X-rays were performed close to the time of the routine chest X-rays hence there were only 296 routine chest X-rays. Amongst these routine chest X-rays five chest X-rays led to interventions and 36 assisted in the management. The interventions were four intercostal drains for pneumothoraces and one nasogastric tube insertion. Of the eight indicated X-rays, four assisted in the management and none led to direct interventions. All five chest X-rays that led to interventions and 32 out of 36 chest X-rays which assisted, were routine. There was no mortality or morbidity from pathology that was undiagnosed by the omission of a chest X-ray. 3.2. Group B: one postoperati e routine X-ray on day In group B, a total of 133 chest X-rays were performed. These included 86 routine and 7 indicated X-rays. Fourteen of the indicated chest X-rays were Table 3 Intervention and assistance analysis (n=100 each group) Group A Group B Chest X-rays Total 30 133 36 Routine 296 86 0 Indicated 8 7 36 Interventions 5 Assistance 36 28 28 Group C performed close to the time of routine chest X-rays, hence no further routine chest X-rays were performed in these instances resulting in only 86 routine chest X-rays instead of the expected 100 routine chest X-rays. In this group four chest X-rays led to interventions and 28 chest X-rays assisted in the management. The interventions were: three intercostal drains for pneumothoraces and one pleural aspiration. Of the 7 indicated chest X-rays, three chest X-rays-rays resulted in interventions and 26 chest X-rays-rays assisted in the management. Amongst the 86 routine chest X-rays, one led to intervention and two assisted in the management. There was no mortality or morbidity attributable to omission of early post-operative routine chest X-rays. 3.3. Group C: chest X-ray only when indicated In group C, 36 chest X-rays were performed. All of these were indicated. These X-rays resulted in four interventions, which were: two intercostal drains for pneumothoraces and two vigorous endobronchial suction/chest physiotherapy for lobar collapse in intubated patients. Twenty-eight X-rays assisted in the management of the patients. There was no mortality or morbidity due to omission of routine postoperative chest X-rays. 3.. Total/routine X-rays Overall there is a significant reduction in the total number of chest X-rays performed across the three groups, 30 in group A, 136 in group B, 36 in group C. This is mainly due to a steep reduction in routine chest X-rays from 296 in group A to 86 in Group B and none in Group C. 3.5. Clinically indicated chest X-rays The total number of clinically indicated chest X-rays remained at a reasonably constant level at 7 and 36 in groups B and C respectively with the same numbers of interventions and clinical or assistance as in group A, despite the decrease of routine in clinical management in these groups even though there were not as many routine X-rays performed in these groups as in group A. The total number of indicated chest X-rays in group A was only 8. This can be explained by the large number of routine X-rays performed in this group which would have covered most clinical situations. 3.6. Assistance and inter ention alue The clinical situations in all groups where X-rays were of assistance, include assessment of postoperative shortness of breath, suspected respiratory infection, and check X-rays following procedures such as central lines,
P.S.R. Rao et al. / European Journal of Cardio-thoracic Surgery 12 (1997) 72 729 727 Table Routine/indicated chest X-ray analysis Group A Group B Group C Routine (296) Indicated (8) Routine (86) Indicated (7) Routine (0) Indicated (396) Intervention 5 0 1 3 0 Assistance 32 2 26 0 28 chest drains. The total number of chest X-rays that assisted management remained constant across the three groups; in group A 36 out of 30 X-rays, in group B 28 out of 133 chest X-rays, in group C 28 out of 36 helped in the management. Similarly, the total number of chest X-rays that directly resulted in interventions remained constant at five, four and four in groups A, B and C (Table 3). The interventions in the three groups (Table ) were chest drainage for pneumothorax (nine), pleural aspiration (one), nasogastric tube decompression in a patient with grossly distended stomach with respiratory embarrassment (one) and endobronchial suction for lobar collapse (two). In group A, five chest X-rays resulted directly in interventions out of the total 30 chest X-rays. The interventions in this group are four chest drain insertions and one nasogastric tube insertion to decompress the distended stomach. In group B, four chest X-rays directly led to interventions out of the total 133 chest X-rays. The interventions are three chest drain insertions for pneumothoraces and one pleural aspiration. In 7 indicated chest X-rays 28 assisted the management, while out of 86 routine chest X-rays only two X-rays assisted and one led to intervention in this group. In group C, out of four chest X-rays resulting in interventions two led to chest drains insertions and two chest X-rays led to endobronchial suction and chest physiotherapy for lobar collapse out of a total of 36 chest X-rays. Twenty-eight chest X-rays assisted in the management. There was no mortality or morbidity attributable to lack of routine chest X-ray in all the three groups.. Discussion Routine postoperative chest X-rays in cardiac surgery is a standard practice in many centres around in the world. The exact benefit of this practice has been the questioned by some authors [ 8]. Several postoperative radiological findings are described [1 3] and many of these will resolve spontaneously. It is also known that many radiological features like minor atelectasis and minimal to moderate pleural collections may not lead to change in management. Obviously, much depends on the clinical status of the patient [3]. Hence it is not surprising that chest X-rays are found to be of greater use only when performed with clinical indication rather than being performed routinely. However, most of the currently available literature refers to evaluation of routine immediate postoperative chest X-rays only. We have decided to clarify this issue further by conducting this study to evaluate all routine postoperative chest X-rays in satisfactorily recovering adult cardiac surgical patients. The group of patients whose postoperative recovery has become complicated resulting in a and had to stay of more than 36 h in intensive care unit, and those who died expired within 36 h were excluded from the study. Obviously these groups of patients would have required multiple indicated chest X-rays as a part of their intensive care management..1. Inter entions In our experience the interventions that are exclusively decided by chest X-rays are usually pleural drainage for pneumothorax or pleural effusion. In one instance a nasogastric tube was passed to decompress a grossly distended stomach in the immediate postoperative chest X-ray in a patient with associated breathing difficulty. Two patients had therapeutic intervention for lobar collapse. The number of interventions based on chest X-rays alone have remained constant at five, four and four for groups A, B, and C respectively although the total number of chest X-rays performed have decreased remarkably (see Table 3)..2. Assistance alue These X-rays might have been performed on the basis of protocol or when indicated. Assessment of the assistance value of the X-rays is difficult to quantify, as it is. This is more subjective in evaluation than the intervention assessment. The clinical situations vary considerably just as the X-ray features do these include the supportive role of postoperative chest X-rays in the decision The supportive role of postoperative chest X-rays applied to a wide variations of clinical situations; hemodynamic instability, making regarding
728 P.S.R. Rao et al. / European Journal of Cardio-thoracic Surgery 12 (1997) 72 729 bleeding, poor arterial blood gases, shortness of breath, and check X-rays for central venous lines, Swan Ganz catheters, intra-aortic balloon pump (IABP), chest drains, resolving chest infections, follow-up of pleural collections or pneumothoraces. These X-rays would have helped in a variety of clinical situations to modify existing treatment such as the use of diuretics in the presence of interstitial oedema on chest X-ray, or chest physiotherapy in the presence of lobar collapse. There are obviously a variety of clinical situations with a variety of chest X-ray features leading to a variety of management changes. However, in our study the number of chest X-rays that have helped in the management of the patient have remained constant at 36, 28 and 28 in the three Groups A, B and C, respectively, despite the variety of clinical situations. In group A 50% of the eight indicated chest X-rays helped in the management, while 12.5% (37 in 296 chest X-rays) of routine chest X-rays contributed to the patient management. In group B out of 7 indicated chest X-rays, 26 helped and three resulted in interventions. This is 62% of the indicated chest X-rays. This can be compared with two chest X-rays assisting and one chest X-ray leading to intervention out of 86 routine chest X-rays. This gives a 2.3% assistance and 1.21% intervention rate in this group amongst the routine chest X-rays. It is of interest to note that in group C, when only clinically indicated X-rays were performed, 89% of chest X-rays have yielded useful information for management of patients This group had four chest X-rays leading to interventions and 28 chest X-rays assisting treatment out of a total of 36 indicated chest X-rays. There is no additional mortality or morbidity in this group as compared with other two groups due to lack of routine chest X-rays (see Table and Table 5). These data clearly indicate that chest X-rays are most beneficial when performed in the presence of a clinical indication at any stage in the post operative period of a satisfactorily recovering adult cardiac surgical patient. Thus we believe routine postoperative chest X-rays are not essential. There is no increased morbidity or mortality due to lack of routine chest X-rays. By adopting this policy, there is considerable savings not only financially but also in terms of manpower Table 5 Percentage of chest X-rays that assisted in the treatment or resulted in the interventions Routine chest X-rays Indicated chest X-rays (%) (%) Group A 12.5 50 Group B 3. 62 Group C 89 resources and staff-patient safety. An approximate estimate of saving of 2600 chest X-rays per thousand adult cardiac cases per annum has been made in our centre alone. At a conservative estimate of UK 15 per chest X-ray this would mean a projected saving of UK 39 000 per annum in a unit with 1000 open heart procedures per year. The issue of medico-legal implication of a missed swab would be considered by some to be more damaging economically than the savings mentioned above. However, just as it is generally not a practice to perform routine abdominal X-rays following abdominal surgery; there is no need for routine chest X-rays to look for missing swabs. Accurate swab counting protocol in the operating rooms has always been the main safeguard mechanism against this complication. Moreover, the hemodynamic instability that is likely to occur in the immediate postoperative period while lifting the patient in the process of performing an X-ray can be avoided. while lifting the patient in the process of performing an X-ray. There are other benefits as well with this policy. (1) It negates the need for nurses to lift patients in Intensive care unit and High dependency unit for placement of X-ray plate. This will prevent back injury and protect the health and safety of the nursing staff. (2) It decreases multiple visits to the cardiac intensive care to perform immediate postoperative chest X-rays and first day postoperative chest X-ray thus saving the Radiographer s time. (3) It also saves the time of portering services by reducing the need to transfer the early mobilising patient for chest X-rays to the Radiology department. () It decreases further the small risk of radiation exposure for staff and patients. 5. Conclusions Routine chest X-rays are not essential to monitor the progress of satisfactorily recovering adult cardiac surgical patients. 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