Injury (1992) 23, (8), 537-541
Printed in Great Britain
Does plaster immobilization pulmonary embolism?
533
predispose to
A. M. Clarke and I. G. Winson Department
of Orthopaedic
Surgery, Northern
General Hospital, Sheffield, UK
Over a s-year study period, 22 patients with isolated lower limb injuries who were immobilized in a plaster cast developed a pulmonary embolus. This information was not available from orthopaedic audit. Better cross-specialty accounting is required if complications that span different hospital specialties are to be fully elucidated. This problem wus heightened by the number of emboli occum’ng while the patient was being treated as an outpatient.
Introduction Since Virchow (1858) described the clinical entities of venous thrombosis and pulmonary embolism, clinicians have sought an answer to their prevention. Despite attempts at prophylaxis, over 142 000 fatal and 285 000 non-fatal cases of pulmonary embolism occur annually in the USA (Sasahara, 1974). It is generally agreed that the elderly, immobilized or traumatized patient is most at risk from a pulmonary embolism (Soloff and Rodman, 1967). In other patient groups, such as those with malignant disease, and others who have recently undergone surgery, have welldocumented incidences ranging from 4.5 per cent to 13.1 per cent in the former and from 9.4 per cent to 40.3 per cent in the latter (Wolfe and Sabiston, 1980). Although any form of immobilization places the patient at increased risk of pulmonary embolism, the application of a plaster cast, while seemingly a possible predisposing factor, seems to have escaped review.
Results Over the 5-year period, a total of 691 patients with pulmonary emboli were found. A total of 22 patients who had sustained isolated extremity injuries and who were immobilized in plaster went on to develop pulmonary emboli. This represents 3.2 per cent of the total number of hospitalized patients with pulmonary emboli over the study period. These cases were drawn from the Northern General Hospital’s catchment of 220 000 patients. Of the 22 patients, 15 had been discharged home from the orthopaedic wards, but were subsequently admitted with a diagnosis of pulmonary embolism under the care of the general physicians. One patient died of a massive embolus shortly after admission. Those injuries associated with the development of pulmonary embolism are shown below: 1.
2. 3. 4.
5. 6.
10 Fractured ankles (45%) 5 Fractured tibias (24%) 3 Fractured patellas (14%) 2 Tibial plateau fractures 1 Femoral condyle fracture 1 Open tendo achillis repair
Further information Table I.
Patients and methods Patients suffering from pulmonary emboli over the 5-year period 1986-1990, inclusive, were identified from the records of the anticoagulation clinic and from patient discharge data at the Northern General Hospital, Sheffield. Those cases of fatal embolization which occurred at home could not be identified from the Coroner’s office and were excluded. From these data we were able to conduct a comparative review of those patients with pulmonary emboli who had also been immobilized in a plaster cast. Additional information on the age, sex, diagnosis and period from injury allowed the analysis of which patient groups were most at risk. Those patients with other important injuries, reasons for confinement, or other risk factors for pulmonary emboli (e.g. 0 1992 Butterworth-Heinemann 0020-1383/92/080537-02
past history of pulmonary embolus) were excluded, so that only those patients with plaster casts alone as the cause of their disability were included. All cases had pulmonary emboli diagnosed by a ventilation/perfusion mismatch on isotope scanning.
Ltd
on the individual
cases is given
in
Discussion It is generally accepted that venous thrombosis in the lower half of the body predisposes to pulmonary embolism. During the period of study we found no recorded cases of this condition in patients with a cast on the upper limb, but the high proportion of cases with above-knee plasters who were non-weight bearing should be noted. This group included the one fatality. These two factors are likely to encourage venous stagnation and reduce the venous return from the lower limb. It was also interesting to note that all the cases above can be attributed to accidental injury rather than from elective
injury:
534
Table I. Details of patients with plaster casts and pulmonary
the British Journal of Accident Surgery (1992) Vol. 23/No.
emboli
Operation Fracture /injury
Age Sex
Ankle Ankle Ankle Ankle Ankle Ankle Ankle Ankle Ankle Ankle Tibia Tibia Tibia Tibia Tibia Patella Pateila Patella Tibia1 plateau Tibia1 plateau Femoral condyle Tendo achillis
53 61 43 49 54 45 60 73 57 50 73 39 72 62 63 64 65 65 68 73 86 22
Mean age
F F F F M M F F F F F M F M M M f F M M F M
8
Weigh bearing
POP
Fracture to PE MlJA
Open
+ + -
-
+ + + -
+ + _ -
+
-
-
+ + +
-
BK
+
+ + + + +
-
-
AK
No
Yes
-
+ + + + -
-
+ +
-
+
+ +
+ -
-
-
+ +
+ + + + + + + + + + + + +
+ + + + + + + + + + + + +
-
-
-
59 years
(daYsI 7 10 ::* 28 28 34 35 42 60 7 7 14 21 25 8 14 21 10 28 35 10 Mean 22 days
‘Denotes died. MUA. manipulation under anaesthesia. BK, below knee, AK, above-knee. PE, pulmonary embolism.
surgery. Several factors may be responsible for this: first, the proportionally lower number of casts applied for elective surgery; second, that it has been policy to pursue active prophylactic measures in elective surgical patients during the period of study; and third, that elective surgery represents a more controlled local soft tissue and generalized physiological insult. The preponderance of ankle fractures may reflect the higher number of patients with this common injury, as up to one-half of all fractures in the lower limb in our hospital occur around the ankle. The number of middle-aged patients treated nonoperatively with above-knee casts and who were nonweight bearing gives cause for concern as it seems that this is the group most at risk from thromboembolism. Careful consideration should therefore be given to the necessity of non-weight bearing in a patient with a lower limb injury. The middle-aged female patient with an undisplaced ankle fracture would seem to typify the patient at risk. The mean interval between injury and pulmonary embolism of 22 days, is long enough to ensure that the majority of patients will have their embolic episode at home. However, we were unable to retrieve data on any deaths due to pulmonary embolus occurring at home, so that we cannot comment on the true incidence of this as a fatal complication. Nevertheless, the number of non-fatal cases occurring in this study should give rise to serious consideration for the use of prophylactic antithromboembolic measures in ‘at-risk’ groups. The construction of this paper would not have been possible if we had used orthopaedic audit alone, and in particular the presence of a major complication would not have been detected. This highlights the inadequacy of the largely inpatient-based methods of audit which are in current practice.
Further prospective study is required if the magnitude of this problem is to be fully appreciated. Unfortunately, it is impractical at present to measure the spontaneous incidence of pulmonary emboli in our resident population.
Acknowledgement The authors are grateful to Mr M. Forrest, Northern General Hospital’s Information Technology Manager for his help in retrieving the data for this study. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
References Sasahara A. A. (1974) Therapy for pulmonary
embolism. JAMA 229,179s. Soloff L. A. and Rodman T. (1967) Acute pulmonary embolism. Am. Heart]. 74, 711. Virchow R. (1858) Die cellularpathologie in ihrer begrmdung auf physiologische und pafhologische gewelbelehre. Berlin: A Hirshwald. Wolfe W. G. and Sabiston D. C. Jr. (1980) Pulmonary Embolism.
Philadelphia: W. B. Saunders, 3.
Paper accepted 29 May 1992.
Requests for reprints should be addressed to: Mr 1. Winson
Department of Orthopaedic Surgery, Southmead Westbury-on-Trym, Bristol BSlO 9NB. UK.
FRCS,
Hospital,
Printed in Great Britain
Does plaster immobilization pulmonary embolism?
533
predispose to
A. M. Clarke and I. G. Winson Department
of Orthopaedic
Surgery, Northern
General Hospital, Sheffield, UK
Over a s-year study period, 22 patients with isolated lower limb injuries who were immobilized in a plaster cast developed a pulmonary embolus. This information was not available from orthopaedic audit. Better cross-specialty accounting is required if complications that span different hospital specialties are to be fully elucidated. This problem wus heightened by the number of emboli occum’ng while the patient was being treated as an outpatient.
Introduction Since Virchow (1858) described the clinical entities of venous thrombosis and pulmonary embolism, clinicians have sought an answer to their prevention. Despite attempts at prophylaxis, over 142 000 fatal and 285 000 non-fatal cases of pulmonary embolism occur annually in the USA (Sasahara, 1974). It is generally agreed that the elderly, immobilized or traumatized patient is most at risk from a pulmonary embolism (Soloff and Rodman, 1967). In other patient groups, such as those with malignant disease, and others who have recently undergone surgery, have welldocumented incidences ranging from 4.5 per cent to 13.1 per cent in the former and from 9.4 per cent to 40.3 per cent in the latter (Wolfe and Sabiston, 1980). Although any form of immobilization places the patient at increased risk of pulmonary embolism, the application of a plaster cast, while seemingly a possible predisposing factor, seems to have escaped review.
Results Over the 5-year period, a total of 691 patients with pulmonary emboli were found. A total of 22 patients who had sustained isolated extremity injuries and who were immobilized in plaster went on to develop pulmonary emboli. This represents 3.2 per cent of the total number of hospitalized patients with pulmonary emboli over the study period. These cases were drawn from the Northern General Hospital’s catchment of 220 000 patients. Of the 22 patients, 15 had been discharged home from the orthopaedic wards, but were subsequently admitted with a diagnosis of pulmonary embolism under the care of the general physicians. One patient died of a massive embolus shortly after admission. Those injuries associated with the development of pulmonary embolism are shown below: 1.
2. 3. 4.
5. 6.
10 Fractured ankles (45%) 5 Fractured tibias (24%) 3 Fractured patellas (14%) 2 Tibial plateau fractures 1 Femoral condyle fracture 1 Open tendo achillis repair
Further information Table I.
Patients and methods Patients suffering from pulmonary emboli over the 5-year period 1986-1990, inclusive, were identified from the records of the anticoagulation clinic and from patient discharge data at the Northern General Hospital, Sheffield. Those cases of fatal embolization which occurred at home could not be identified from the Coroner’s office and were excluded. From these data we were able to conduct a comparative review of those patients with pulmonary emboli who had also been immobilized in a plaster cast. Additional information on the age, sex, diagnosis and period from injury allowed the analysis of which patient groups were most at risk. Those patients with other important injuries, reasons for confinement, or other risk factors for pulmonary emboli (e.g. 0 1992 Butterworth-Heinemann 0020-1383/92/080537-02
past history of pulmonary embolus) were excluded, so that only those patients with plaster casts alone as the cause of their disability were included. All cases had pulmonary emboli diagnosed by a ventilation/perfusion mismatch on isotope scanning.
Ltd
on the individual
cases is given
in
Discussion It is generally accepted that venous thrombosis in the lower half of the body predisposes to pulmonary embolism. During the period of study we found no recorded cases of this condition in patients with a cast on the upper limb, but the high proportion of cases with above-knee plasters who were non-weight bearing should be noted. This group included the one fatality. These two factors are likely to encourage venous stagnation and reduce the venous return from the lower limb. It was also interesting to note that all the cases above can be attributed to accidental injury rather than from elective
injury:
534
Table I. Details of patients with plaster casts and pulmonary
the British Journal of Accident Surgery (1992) Vol. 23/No.
emboli
Operation Fracture /injury
Age Sex
Ankle Ankle Ankle Ankle Ankle Ankle Ankle Ankle Ankle Ankle Tibia Tibia Tibia Tibia Tibia Patella Pateila Patella Tibia1 plateau Tibia1 plateau Femoral condyle Tendo achillis
53 61 43 49 54 45 60 73 57 50 73 39 72 62 63 64 65 65 68 73 86 22
Mean age
F F F F M M F F F F F M F M M M f F M M F M
8
Weigh bearing
POP
Fracture to PE MlJA
Open
+ + -
-
+ + + -
+ + _ -
+
-
-
+ + +
-
BK
+
+ + + + +
-
-
AK
No
Yes
-
+ + + + -
-
+ +
-
+
+ +
+ -
-
-
+ +
+ + + + + + + + + + + + +
+ + + + + + + + + + + + +
-
-
-
59 years
(daYsI 7 10 ::* 28 28 34 35 42 60 7 7 14 21 25 8 14 21 10 28 35 10 Mean 22 days
‘Denotes died. MUA. manipulation under anaesthesia. BK, below knee, AK, above-knee. PE, pulmonary embolism.
surgery. Several factors may be responsible for this: first, the proportionally lower number of casts applied for elective surgery; second, that it has been policy to pursue active prophylactic measures in elective surgical patients during the period of study; and third, that elective surgery represents a more controlled local soft tissue and generalized physiological insult. The preponderance of ankle fractures may reflect the higher number of patients with this common injury, as up to one-half of all fractures in the lower limb in our hospital occur around the ankle. The number of middle-aged patients treated nonoperatively with above-knee casts and who were nonweight bearing gives cause for concern as it seems that this is the group most at risk from thromboembolism. Careful consideration should therefore be given to the necessity of non-weight bearing in a patient with a lower limb injury. The middle-aged female patient with an undisplaced ankle fracture would seem to typify the patient at risk. The mean interval between injury and pulmonary embolism of 22 days, is long enough to ensure that the majority of patients will have their embolic episode at home. However, we were unable to retrieve data on any deaths due to pulmonary embolus occurring at home, so that we cannot comment on the true incidence of this as a fatal complication. Nevertheless, the number of non-fatal cases occurring in this study should give rise to serious consideration for the use of prophylactic antithromboembolic measures in ‘at-risk’ groups. The construction of this paper would not have been possible if we had used orthopaedic audit alone, and in particular the presence of a major complication would not have been detected. This highlights the inadequacy of the largely inpatient-based methods of audit which are in current practice.
Further prospective study is required if the magnitude of this problem is to be fully appreciated. Unfortunately, it is impractical at present to measure the spontaneous incidence of pulmonary emboli in our resident population.
Acknowledgement The authors are grateful to Mr M. Forrest, Northern General Hospital’s Information Technology Manager for his help in retrieving the data for this study. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
References Sasahara A. A. (1974) Therapy for pulmonary
embolism. JAMA 229,179s. Soloff L. A. and Rodman T. (1967) Acute pulmonary embolism. Am. Heart]. 74, 711. Virchow R. (1858) Die cellularpathologie in ihrer begrmdung auf physiologische und pafhologische gewelbelehre. Berlin: A Hirshwald. Wolfe W. G. and Sabiston D. C. Jr. (1980) Pulmonary Embolism.
Philadelphia: W. B. Saunders, 3.
Paper accepted 29 May 1992.
Requests for reprints should be addressed to: Mr 1. Winson
Department of Orthopaedic Surgery, Southmead Westbury-on-Trym, Bristol BSlO 9NB. UK.
FRCS,
Hospital,
