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Prospective Assessment of a Protocol for Selective Ordering of Preoperative Chest X-Rays
PEIUOPERA'1"'IVE CARE
body p:<'otein) of less Uum 0.77. P:;_.otein-depleted patients demonstrated a significant reduction in respiratory muscle strength, vital capacity and peak expiratory flow rate. There was no significant difference in the incidence of atelectasis between the 2 patient categol'ies, with 20 of 41 control patients and 16 of 39 proteindepleted patients having this complication. However, the risk of pneumonia was significantly different between the 2 groups, and it occurred in 8 of 39 proteindepleted patients (20.5 per cent) compared to only 3 of 41 controls (7.3 per cent) (p <0.05). Three proteindepleted patients died: 2 of pneumonia and 1 of massive pulmonary embolization. The authors conclude that pl'otein depletion increases the rate of postoperative pulmonary complications by interfering with respiratory skeletal muscle function and that efforts should be made to correct this risk factor preoperatively. Charles B. Brendler, M.D. Prospective Assessment of a Protocol for Selective Ordering of Preoperative Chest X-Rays
Y.
M. SzATAN AND B. Departement de Biostatistique et Informatique Medicale, Hopital Saint-Louis, Paris and Departement d'Anesthesiologie, Hopital Rothchild, Paris, France CHARPAK, C. BLERY, C. CHASTANG,
FOURGEAUX,
Canad. J. Anaesth., 35: 259-264, 1988 Routine preoperative chest x-rays are still widely employed worldwide, although results of many studies do not support their broad utilization. A protocol for selective ordering of preoperative chest x-rays, according to the patient's clinical status, medical history and scheduled surgery, was developed and implemented in a teaching hospital in Paris. The utilization of the protocol during a one-year period was evaluated. Eleven hundred and one chest x-rays were ordered in 3866 patients (28 per cent). Five hundred and sixty-eight x-rays (52 per tent) were abnormal. One hundred and sixty-six (15 per cent) were considered useful by the anaesthetists, who took into account the entire hospital course, although only 51 (5 per cent) had an impact on the surgical plan or anaesthetic management. Among the 2765 patients who did not have a preoperative chest x-ray, two patients could have benefited from the chest x-ray, in the view of anaesthetists. Chart review for these two patients and for patients who had perioperative complications in the absence of a preoperative chest x-ray revealed that no complications could be linked to the lack of preoperative chest x-ray ordering, This study shows that the abandonment of routine ordering of preoperative chest x-rays does not produce adverse effects on patient care.
Editorial Comment: This is a prospective evaluation of a protocol for selective ordering of preoperative chest x-rays. The study was performed over 1 year and involved 3,866 patients in whom 1,101 chest x-rays were ordered. Indications for preoperative chest l'adiographs included any lung diseases, cardiovascular diseases, known malignant diseases, major surgical emergencies, current smoking history in patients more than 50 years old, immunodepression and lack of a prior health examination in immigrants. With this protocol chest xrays led to a modification of medical decisions in 51 of 1,101 patients (5 per cent) having them. In only 2 of
1051
2, 765 patients not having a preoperative chest x~:ray did the anesthesiologist believe that such an x-ray woul.d have been potentially useful. Among the 3,866 patients 44 died, only 1 of whom had not had a preoperative chest x-ray and her death could not be attributed to this factor. The authol's conclude that l.t l.s possible to abandon :routine ordel'ing of preoperative chest x-rays without undesirable effects on patient care and outcome. Protocols suggesting which patients may benefit from a p:reopeJrative chest x-:ray may facilitate their acceptance by clinicians. Charles B. Brendle:r, M.D. Prevention of Venous Thromboembolism in General Surgical Patients: Results of a Meta-Analysis
G. P. CLAGETT AND J. S. REISCH, Departments of Surgery and Academic Computing Services, The University of Texas Southwestern Medical Center at Dallas, Southwestern Medical School, Dallas, Texas Ann. Surg., 208: 227-240, 1988 The results of randomized clinical trials evaluating commonly used methods of deep vein thrombosis (DVT) prophylaxis in moderate- and high-risk general surgery patients were pooled to obtain an unbiased estimate of efficacy and risks. Low-dose heparin (LDH), dextran, heparin-dihydroergotamine (HDHE), intermittant pneumatic compression (IPC), and graded elastic stockings significantly reduced the incidence of DVT; aspirin was ineffective. In contrast to other methods, elastic stockings have not been adequately studied to determine their value in reducing DVT in high-risk patients, such as those with malignancy. Only LDH and dextran were studied in numbers of patients sufficient for demonstrating a clear reduction in pulmonary embolism (PE). In comparison studies, LDH was superior to dextran in preventing DVT, but the two agents were equivalent in protecting against PE. Although HDHE was marginally better than LDH in preventing DVT, it appeared to have no advantage in preventing PE-at least in moderaterisk patients. The incidence of major hemorrhage was not increased with any of the prophylactic agents. However, wound hematomas occurred significantly more frequently with LDH, an effect noted in the pooled data from double-blind and open trials. In comparison trials with LDH, both dextran and HDHE had significantly fewer wound hematomas. LDH administered every 8 hours appeared more effective in reducing DVT than LDH administered every 12 hours; the incidence of wound hematomas was equivalent with both regimens,
Editorial Comment: In this important review of postoperative thromboemboli.c disease the authors have used the technique of meta-analysh; to combine and analyze the re~mlts of randomized clinical trials. By pooling the results of several clinical trials, meta-analysis increases the statistical power for primary end points and helps to resolve uncertainty when reports disagree. The technique is appropriate particularly when an end point is so rare that huge clinical trials are necessary for definitive answers, as is the case with fatal postoperative pulmonary embolism. With this method of data analysis the authors have shown clearly that low dose heparin :reduces the incidence of fatal postoperative pulmonary embolism. The pooled data from 24 randomized trials
body p:<'otein) of less Uum 0.77. P:;_.otein-depleted patients demonstrated a significant reduction in respiratory muscle strength, vital capacity and peak expiratory flow rate. There was no significant difference in the incidence of atelectasis between the 2 patient categol'ies, with 20 of 41 control patients and 16 of 39 proteindepleted patients having this complication. However, the risk of pneumonia was significantly different between the 2 groups, and it occurred in 8 of 39 proteindepleted patients (20.5 per cent) compared to only 3 of 41 controls (7.3 per cent) (p <0.05). Three proteindepleted patients died: 2 of pneumonia and 1 of massive pulmonary embolization. The authors conclude that pl'otein depletion increases the rate of postoperative pulmonary complications by interfering with respiratory skeletal muscle function and that efforts should be made to correct this risk factor preoperatively. Charles B. Brendler, M.D. Prospective Assessment of a Protocol for Selective Ordering of Preoperative Chest X-Rays
Y.
M. SzATAN AND B. Departement de Biostatistique et Informatique Medicale, Hopital Saint-Louis, Paris and Departement d'Anesthesiologie, Hopital Rothchild, Paris, France CHARPAK, C. BLERY, C. CHASTANG,
FOURGEAUX,
Canad. J. Anaesth., 35: 259-264, 1988 Routine preoperative chest x-rays are still widely employed worldwide, although results of many studies do not support their broad utilization. A protocol for selective ordering of preoperative chest x-rays, according to the patient's clinical status, medical history and scheduled surgery, was developed and implemented in a teaching hospital in Paris. The utilization of the protocol during a one-year period was evaluated. Eleven hundred and one chest x-rays were ordered in 3866 patients (28 per cent). Five hundred and sixty-eight x-rays (52 per tent) were abnormal. One hundred and sixty-six (15 per cent) were considered useful by the anaesthetists, who took into account the entire hospital course, although only 51 (5 per cent) had an impact on the surgical plan or anaesthetic management. Among the 2765 patients who did not have a preoperative chest x-ray, two patients could have benefited from the chest x-ray, in the view of anaesthetists. Chart review for these two patients and for patients who had perioperative complications in the absence of a preoperative chest x-ray revealed that no complications could be linked to the lack of preoperative chest x-ray ordering, This study shows that the abandonment of routine ordering of preoperative chest x-rays does not produce adverse effects on patient care.
Editorial Comment: This is a prospective evaluation of a protocol for selective ordering of preoperative chest x-rays. The study was performed over 1 year and involved 3,866 patients in whom 1,101 chest x-rays were ordered. Indications for preoperative chest l'adiographs included any lung diseases, cardiovascular diseases, known malignant diseases, major surgical emergencies, current smoking history in patients more than 50 years old, immunodepression and lack of a prior health examination in immigrants. With this protocol chest xrays led to a modification of medical decisions in 51 of 1,101 patients (5 per cent) having them. In only 2 of
1051
2, 765 patients not having a preoperative chest x~:ray did the anesthesiologist believe that such an x-ray woul.d have been potentially useful. Among the 3,866 patients 44 died, only 1 of whom had not had a preoperative chest x-ray and her death could not be attributed to this factor. The authol's conclude that l.t l.s possible to abandon :routine ordel'ing of preoperative chest x-rays without undesirable effects on patient care and outcome. Protocols suggesting which patients may benefit from a p:reopeJrative chest x-:ray may facilitate their acceptance by clinicians. Charles B. Brendle:r, M.D. Prevention of Venous Thromboembolism in General Surgical Patients: Results of a Meta-Analysis
G. P. CLAGETT AND J. S. REISCH, Departments of Surgery and Academic Computing Services, The University of Texas Southwestern Medical Center at Dallas, Southwestern Medical School, Dallas, Texas Ann. Surg., 208: 227-240, 1988 The results of randomized clinical trials evaluating commonly used methods of deep vein thrombosis (DVT) prophylaxis in moderate- and high-risk general surgery patients were pooled to obtain an unbiased estimate of efficacy and risks. Low-dose heparin (LDH), dextran, heparin-dihydroergotamine (HDHE), intermittant pneumatic compression (IPC), and graded elastic stockings significantly reduced the incidence of DVT; aspirin was ineffective. In contrast to other methods, elastic stockings have not been adequately studied to determine their value in reducing DVT in high-risk patients, such as those with malignancy. Only LDH and dextran were studied in numbers of patients sufficient for demonstrating a clear reduction in pulmonary embolism (PE). In comparison studies, LDH was superior to dextran in preventing DVT, but the two agents were equivalent in protecting against PE. Although HDHE was marginally better than LDH in preventing DVT, it appeared to have no advantage in preventing PE-at least in moderaterisk patients. The incidence of major hemorrhage was not increased with any of the prophylactic agents. However, wound hematomas occurred significantly more frequently with LDH, an effect noted in the pooled data from double-blind and open trials. In comparison trials with LDH, both dextran and HDHE had significantly fewer wound hematomas. LDH administered every 8 hours appeared more effective in reducing DVT than LDH administered every 12 hours; the incidence of wound hematomas was equivalent with both regimens,
Editorial Comment: In this important review of postoperative thromboemboli.c disease the authors have used the technique of meta-analysh; to combine and analyze the re~mlts of randomized clinical trials. By pooling the results of several clinical trials, meta-analysis increases the statistical power for primary end points and helps to resolve uncertainty when reports disagree. The technique is appropriate particularly when an end point is so rare that huge clinical trials are necessary for definitive answers, as is the case with fatal postoperative pulmonary embolism. With this method of data analysis the authors have shown clearly that low dose heparin :reduces the incidence of fatal postoperative pulmonary embolism. The pooled data from 24 randomized trials