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Elastic compression in the prevention of venous stasis
Elastic Compression in the Prevention of Venous Stasis A Critical Reevaluation Charles E. Lewis, Jr, MD,* Albuquerque, John Antoine, MD, Albuquerque,
New Mexico
New Mexico
Charles Mueller, MD, Albuquerque, William A. Talbot, MD, Albuquerque,
New Mexico New Mexico
Ram Swaroop, PhD, Edwards, California W. Sterling Edwards, MD, Albuquerque,
New Mexico
Deep venous thrombosis continues to complicate even the most routine operative procedures and the incidence may approach 50 per cent [14]. It is even higher in the elderly [2,3] and certain other high-risk groups [5]. In almost half of these, thrombosis has been shown to have begun during the operation [6]. Thus, in view of the serious sequelae associated with this process, prophylaxis is receiving increasing emphasis [3,5,7-g]. Browse [IO] has recently outlined the problem and enumerated many of the mechanical methods of prophylaxis presently available. To be effective on a large scale, any such technic must be readily available, easy to use, reasonably economical, and without serious additional risk. In addition, no matter how effective, the proposed technic must be acceptable to the surgeon or he will not use it. In that regard, McLachlin et al [II] have convincingly shown that leg elevation enhances venous clearance from the legs and we have published data that support their conclusions [12]. We were, nevertheless, unable to persuade a group of our colleagues to use the Trendelenberg position as a routine prophylactic measure during operation. On the other hand, elastic compression, thought by some to be ineffective [9,10], enjoys widespread acceptance. We have previously attempted to evaluate the effect of elastic compression on venous stasis in patients under general anesthesia whose legs were carefully wrapped with elastic bandages [12]. This particular experiment was abandoned, however, after only seven patients were studied when it became apparent that no matter how carefully the elastic From the Departments of Surgery and Radiology, University of New Mexico School of Medicine, and Veterans Administration Hospital, Albuquerque, New Mexico, and from the NASA Flight Research Center, Edwards, California. Presented at the Twenty-Eighth Annual Meeting of the Southwestern Surgical Congress, Houston, Texas, May 3-6, 1976. * Present address and reprint requests: 3849 North Boulevard, Baton Rouge, Louisiana 70806.
Volume 132, December 1976
bandages were placed, an inverse gradient was occasionally created by accidentally wrapping the bandage too tightly at the top. The result was a tourniquet effect that delayed rather than enhanced venous emptying. This occurred in two of the seven patients studied and produced a profound delay in venous clearance. Despite this, the average clearance time including these patients (16.7 minutes) was better than that observed in control legs (21.7 minutes), suggesting that elastic compression might prove useful if careful control of the pressure gradient could be reliably effected. Stated in another way, the fit is of critical importance. Theoretically, elastic stockings could be fabricated to avoid this problem, especially if they were individually made for each patient. However, it is doubtful that such a practice would ever be used widely. Prefabricated stockings are available in a number of designs but impose two problems: the fit is of course a compromise and secondly, most incorporate a garter at the top and garters behave like tourniquets. (Figure 1.) Sigel et al [13] have shown that compression applied in a decreasing gradient up the leg will produce the maximal increase in venous flow velocity. This suggests that elastic compression may either function by collapsing superficial veins, thus shunting more blood through the deep system, or by decreasing the volume of the whole venous system. With the previous considerations in mind, the following criteria were adopted for use in selecting a stocking for this study: (1) They should provide a gradient of pressure greatest at the foot, decreasing up the leg. (2) Garters must be avoided. (3) A sufficient selection of sizes must be available to allow an acceptable fit for each patient. A commercially available stocking that most nearly satisfies these criteria was chosen. A clinical evaluation of these stockings using a previously published venographic technic [12] forms the basis of this report.
739
Lewis et al
Figure 1. Conventional elastic stockings showing garter at the top.
Experimental Method Adult volunteers who were scheduled for abdominal operations were studied. General anesthesia was used in all. Complete muscle relaxation was carefully maintained during the venogram by the use of Curare or Anectine. The operating table was precisely leveled and the patients were not moved or their legs manipulated in any way during the study. A stocking was placed on one leg while the other leg was left bare on the operating table; thus, each patient provided his or her own controls. The experimental leg was chosen randomly. Careful attention was given to the fit. The manufacturer’s instructions were rigorously followed except that whenever a patient fell on the border between two sizes the size that provided the looser fit at the top was used. The stockings used are available in nine sizes. Obviously not everyone will be exactly fitted. The most common difficulty occurred in shorter legs with large thighs; two such patients could not be fitted and were not studied. The stocking chosen for this study avoids the problem of garters by means of a panel situated so that it interrupts the band at the top of the stocking and distributes the forces involved over a large area of the anterior thigh. (Figure 2.) Contrast medium (sodium diatrizoate), 50 ml, was rapidly injected into the greater saphenous vein at the ankle bilaterally and directed into the deep system by a tourniquet placed just proximal to the ankle. After injection, the tourniquets were immediately removed and a whole-leg
740
Figure 2. The elastic stocking used in this study; notice panel at the top.
roentgenogram was obtained to verify deep filling. This film was designated as time zero. Subsequent films were obtained at 5 minute intervals until all contrast had cleared on “wet” reading in the operating room. Patients known to be allergic to iodine and those with a history of venous disease or previous leg trauma were all excluded. The venograms were independently read by a colleague from the Department of Radiology who was unaware of the location of the experimental leg at the time he read the venogram. Results Fifteen patients (8 males, 7 females) were studied, ranging in ages from twenty to fifty-nine years (average, 37.1 years). The data are clearance times in minutes obtained by examination of the venograms described previously. Such data are not continuous; in fact, the
The American Journal of Surgery
Elastic Compression TABLE
Stockings
I Whole Leg Clearance Time in Minutes
Patient Stocking Control
-
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
15 20
15 30
10 20
15 25
10 20
20 25
20 45
25 40
20 30
20 45
15 50
20 35
20 20
25 50
25 25
18.3 32.0
Note: Paired ttest: degree of freedom, 14; observed t, 5.25;table value oft, 2.977 (p = 0.01).
precise time of disappearance of contrast from the deep veins is unknown and lies in the 5 minute interval between the last film on which contrast is seen and the subsequent film on which it cannot be seen. For the purpose of analysis a discrete value must be assigned. Either end or even the midpoint of this interval could be used without affecting the result. We have arbitrarily chosen the time of the last film on which contrast can be seen as the endpoint. Whole-leg clearance times are presented in Table I. The mean time observed in legs with stockings was 18.3 minutes which is *much better than the 32.0 minutes observed in the corresponding control legs. The difference, a striking 13.7 minutes, was tested using the paired t test and found to be highly significant (p = 0.01). Many studies examine only the calf and disregard the knee and thigh completely. To individually examine these areas, the venograms were read to provide clearance times for each of these positions separately. These data are presented in Table II along with the mean times and differences observed between the experimental and control legs for each of the positions. The significance of the differences observed was tested using a two-way analysis of variance (ANOVA). In the calf, contrast was cleared in 10.0 minutes from legs with stockings, which is 16.0 minutes faster than the 26.0 minutes in the corresponding control legs. This difference is highly significant (p = 0.01). Likewise, in the popliteal area clearance with stockings was 13.3 minutes whereas in control legs it was 20.0 minutes. The 7.7 minute difference is highly significant (p = 0.01). Finally, deep vein clearance in the thigh is seen to be better in experimental legs (16.7’minutes) than in control legs (26.7 minutes) and the difference (10.0 minutes) is highly significant (p = 0.01). Small differences observed between the three positions are not statistically significant. Comments
The venogram provides the only direct method of examination of blood flow in deep leg veins currently
Volume132,
December 1979
TABLE
II
Clearance Time in Minutes Popliteal
Thigh
___Calf ______~___ s C
S
c
s
c
2 3
15 10 10
20 25 30
0 15 20
10 15 20
0 5 10
0 30 20
4 5 6 7 8 9 10 11 12 13 14 15
15 10 15 20 25 20 10 15 20 20 20 25
25 20 25 20 40 30 15 50 35 20 20 25
10 0 20 15 20 10 20 10 15 5 15 25
25 0 25 25 20 30 20 15 15 20 35 25
0 5 0 15 20 15 15 10 10 15 25 5
15 15 0 45 40 10 45 50 30 15 50 25
Patient 1
16.7 26;7 13.3 20.0 Average 7.7 * 2.69 Difference 10.0 f 2.69 __Note: S = stocking;C = control.
10.0 26.0 16.0 c 2.69 ___-
available in that the areas of stagnation can be seen. Thus, the data presented herein show that stockings not only result in an increased velocity of venous flow in the legs, as Sigel et al [13] have confirmed, but also result in a more rapid clearance of stagnant blood from behind v,enous valves. We agree with Virchow’s original observation [14] that stagnation of blood in the veins is an important etiologic factor in the pathogenesis of deep vein thrombosis (DVT) and suggest that any technic that reduces stasis should result in a decreased incidence of DVT. Tsapogas et al [3] in a small but well controlled prospective study found a much reduced incidence of DVT over controls, using stockings, elevation, early ambulation, and passive exercises (iodine 125 [1251]-tagged fibrinogen uptake). Why then have some investigations of elastic compression based on the lz51-tagged fibrinogen uptake technic failed to show a decrease in DVT? Browse et al [IO] used “elastic stockings” on one leg while the other leg served as a control. Interestingly, the “stocking” they refer to is Tubegrip” elastic tubing (Figure 3) and not a stocking at all. Tubegrip is available in several sizes and weights. G4X is specified as the size used (shown on the right in Fig-
741
Lewis et al
ure 3). When cut in a suitable length, a cylindrical tube is produced. Such a tube when applied to a cylinder of proper dimensions would provide uniform compression. When applied to the leg, however, which is not cylindrical but an inverted cone, an inverse gradient is produced (tightest at the top). This could only impede flow from the leg rather than improve it. It is not surprising, therefore, that these “stockings” were ineffective in reducing DVT; on the
Figure 3. Tubegrip elastic tubing.
contrary, it is surprising that they did not result in a higher incidence of DVT. Rosengarten et al [9] also used this technic and their data are, therefore, also likely to be in error for the same reason. Other authors are sufficiently vague about the stocking technic employed to preclude more careful examination of their conclusions. No one, however, has stressed the critical importance of the fit previously*
Browse [IO] concludes that “stockings only result in a clearance of stagnant blood from behind the valve cusps whenever the pressure is so great that the veins are completely compressed.” Venograms studied herein and those reported earlier clearly refute this allegation. (Figure 4.) The stocking is on the right. Notice that the size of the venous channels on the right under the stockings are only slightly smaller than on the left. Contrast material subsequently cleared from the right leg in approximately half the time required in the control leg on the left, even from behind the venous valves which are clearly seen. With regard to the fit, Sigel et al [13] have previously shown that an optimal compression range is critical to venous flow velocity and that the compression must be applied in a decreasing gradient. Arnoldi [15], using an ingenious radiographic technic to measure flow velocity, has recently verified the results of Sigel et al [I31 and pointed out that during recumbency a much lighter compression is optimal. He was using the same stocking used in the present report. Finally, Ibraham, Scurr, and LeQuesne [16] have just reported a significant decrease in DVT diagnosed by i251-tagged fibrinogen using graded compression in carefully fitted stockings. Summary
Ffgure 4. Venogram with stocking on the right taken at 5 minutes. Note size of venous chanels.
742
The effect of elastic compression on venous flow in the legs provided by carefully fitted stockings has been measured by a venographic technic. The stocking used provides a gradually decreasing compression from ankle to groin. Clearance of stagnant blood from behind venous valves is clearly improved and the differences observed are statistically highly significant. These data suggest that the routine use of carefully fitted compression stockings will result in a decreased incidence of deep vein thrombosis (DVT) and provide a singularly safe, convenient, and noninvasive method of prophylaxis. Evidence presented suggests that at least two investigators have failed to show a decreased incidence of DVT in limbs subjected to elastic compression because the method of compression was inadequate.
The American Journal oi Surgery
Elastic Compression
Stockings
References
Discussion
1. Hunter WC, Sneeden VD, Robertson TD, Snyder GAG: Thrombosis of deep veins of leg; its clinical significance as exemplified in 351 autopsies. Arch Intern Med 68: 1, 1941. 2. Kakkar VV, Howe CT, Nicolaides AN, et al: Deep vein thrombosis of the leg. Is there a “high risk” group? Am J Surg 120: 527, 1970. 3. Tsapogas MJ, Miller R, Peabody RA. et al: Detection of postoperative venous thrombosis and effectiveness of prophylactic measures, studied with the fibrinogen 125-l technique. Arch Surg 101: 149, 1970. 4. McLachlin J, Paterson JC: Some basic observations on venous thrombosis and pulmonary embolism. Surg Gynecol Obstet 98: 1, 1951. 5. Eva& CM, Feil EJ: Prevention of thromboembolic disease after elective surgery of the hip. J Bone Joinf Surg 53A: 1271, 1971. 6. Flanc C, Kakkar VV, Clarke MB: The detection of venous thrombosis of the legs using 1251-labelled fibrinogen. Br J Surg 55: 742, 1968. 7. Flanc C, Kakkar VV, Clarke MB: Postoperative deep-vein thrombosis: effect of intensive prophylaxis. Lancet 1: 477, 1969. 8. Rosengarten DS, Laird J: The effect of leg elevation on the incidence of deep-vein thrombosis after operation. Br J Surg 58: 182, 1971. 9. Rosengarten DS, Laird J, Jeyasingh K, et al: The failure of compression stockings (Tubigrip) to prevent deep venous thrombosis after operation. Br J Surg 57: 296, 1970. 10. Browse NL, Jackson BT, Mayo ME, et al: The value of mechanical methods of preventing postoperative calf vein thrombosis. Br J Surg 61: 219, 1974. 11. McLachlin AD, Jackson BT, Mayo ME, Neggus D: Venous stasis in the lithotomy Trendelenberg position. Can JSurg 10: 414, 1967. 12. Lewis CE Jr, Mueller C, Edwards WS: Venous stasis on the operating table. Am J Surg 24: 780, 1972. 13. Sigel B, Edelstein AL, Savitch L, et al: Type of compression for reducing venous stasis. A study of lower extremities during inactive recumbency. Arch Surg 10: 171, 1975. 14. Virchow RLK: Beitr Exp Path 2: 227, 1846. Quoted by Jorpes JE: Heparin in the Treatment of Thrombosis, 2nd ed. London, Oxford University Press, 1946. 15. Arnoldi CC: Elastic compression in the prevention of deep venous thrombosis. Dan Med Bull 96: 221, 1976. 16. lbraham SZ, Scurr JH, LeQuesne LP: The effect of graded compression on the incidence of postoperative deep venous thrombosis. Presented before the 1 lth Congress, European Society of Surgical Research, Dublin, Ireland, April 27-30, 1976.
Larry Wilkinson (Albuquerque, NM): The employment of each patient as a control makes the results of this small series significant. These facts plus the objective methods of evaluation of venous emptying will result in this becoming a reference study for prophylaxis of venous complications. As the authors have demonstrated, the application of elastic supports may result in the garter effect any place along the extremity. Elastic supports also do not alter the flow through the pelvic veins. Consequently, after learning of the findings of this study, we have been trying another technic of venous emptying. Before making the incision and each 30 minutes thereafter the anesthetist turns the table into steep Trendelenberg position 30 seconds only. This provides the surgeon a pause and likely achieves adequate emptying of all the veins inferior to the heart. The concept that postoperative venous thrombosis begins while the patient is on the operating table is widely accepted. Prevention of this occurrence by whatever means will likely lower the incidence of serious postoperative embolic complications.
VobJmo132, Docembw IS76
Raymond C. Read (Little Rock, AR): Since good evidence recently that perhaps 40 per cent operative thrombi develop preoperatively, do the think that their stockings should be given to the when he or she reports to the surgical ward?
there is of postauthors patient
David B. Roos (Denver, CO): I would like to ask the authors if they have comparative studies for the belowknee stocking compared to the high thigh stocking and secondly, what is the name of the brand stocking he recommends. Charles E. Lewis, Jr (closing): We agree that the patient, particularly the patient who has been ill for some time and who is at bed rest prior to surgery, is well known to be in a higher risk group for this disease and I use these stockings in all those patients from the time they come on the ward until they are discharged. We chose this stocking (TED stocking) mainly because of the panel at the top and the very careful way these stockings were manufactured to provide the gradient that we were looking for. I prefer the long leg stocking.
743
New Mexico
New Mexico
Charles Mueller, MD, Albuquerque, William A. Talbot, MD, Albuquerque,
New Mexico New Mexico
Ram Swaroop, PhD, Edwards, California W. Sterling Edwards, MD, Albuquerque,
New Mexico
Deep venous thrombosis continues to complicate even the most routine operative procedures and the incidence may approach 50 per cent [14]. It is even higher in the elderly [2,3] and certain other high-risk groups [5]. In almost half of these, thrombosis has been shown to have begun during the operation [6]. Thus, in view of the serious sequelae associated with this process, prophylaxis is receiving increasing emphasis [3,5,7-g]. Browse [IO] has recently outlined the problem and enumerated many of the mechanical methods of prophylaxis presently available. To be effective on a large scale, any such technic must be readily available, easy to use, reasonably economical, and without serious additional risk. In addition, no matter how effective, the proposed technic must be acceptable to the surgeon or he will not use it. In that regard, McLachlin et al [II] have convincingly shown that leg elevation enhances venous clearance from the legs and we have published data that support their conclusions [12]. We were, nevertheless, unable to persuade a group of our colleagues to use the Trendelenberg position as a routine prophylactic measure during operation. On the other hand, elastic compression, thought by some to be ineffective [9,10], enjoys widespread acceptance. We have previously attempted to evaluate the effect of elastic compression on venous stasis in patients under general anesthesia whose legs were carefully wrapped with elastic bandages [12]. This particular experiment was abandoned, however, after only seven patients were studied when it became apparent that no matter how carefully the elastic From the Departments of Surgery and Radiology, University of New Mexico School of Medicine, and Veterans Administration Hospital, Albuquerque, New Mexico, and from the NASA Flight Research Center, Edwards, California. Presented at the Twenty-Eighth Annual Meeting of the Southwestern Surgical Congress, Houston, Texas, May 3-6, 1976. * Present address and reprint requests: 3849 North Boulevard, Baton Rouge, Louisiana 70806.
Volume 132, December 1976
bandages were placed, an inverse gradient was occasionally created by accidentally wrapping the bandage too tightly at the top. The result was a tourniquet effect that delayed rather than enhanced venous emptying. This occurred in two of the seven patients studied and produced a profound delay in venous clearance. Despite this, the average clearance time including these patients (16.7 minutes) was better than that observed in control legs (21.7 minutes), suggesting that elastic compression might prove useful if careful control of the pressure gradient could be reliably effected. Stated in another way, the fit is of critical importance. Theoretically, elastic stockings could be fabricated to avoid this problem, especially if they were individually made for each patient. However, it is doubtful that such a practice would ever be used widely. Prefabricated stockings are available in a number of designs but impose two problems: the fit is of course a compromise and secondly, most incorporate a garter at the top and garters behave like tourniquets. (Figure 1.) Sigel et al [13] have shown that compression applied in a decreasing gradient up the leg will produce the maximal increase in venous flow velocity. This suggests that elastic compression may either function by collapsing superficial veins, thus shunting more blood through the deep system, or by decreasing the volume of the whole venous system. With the previous considerations in mind, the following criteria were adopted for use in selecting a stocking for this study: (1) They should provide a gradient of pressure greatest at the foot, decreasing up the leg. (2) Garters must be avoided. (3) A sufficient selection of sizes must be available to allow an acceptable fit for each patient. A commercially available stocking that most nearly satisfies these criteria was chosen. A clinical evaluation of these stockings using a previously published venographic technic [12] forms the basis of this report.
739
Lewis et al
Figure 1. Conventional elastic stockings showing garter at the top.
Experimental Method Adult volunteers who were scheduled for abdominal operations were studied. General anesthesia was used in all. Complete muscle relaxation was carefully maintained during the venogram by the use of Curare or Anectine. The operating table was precisely leveled and the patients were not moved or their legs manipulated in any way during the study. A stocking was placed on one leg while the other leg was left bare on the operating table; thus, each patient provided his or her own controls. The experimental leg was chosen randomly. Careful attention was given to the fit. The manufacturer’s instructions were rigorously followed except that whenever a patient fell on the border between two sizes the size that provided the looser fit at the top was used. The stockings used are available in nine sizes. Obviously not everyone will be exactly fitted. The most common difficulty occurred in shorter legs with large thighs; two such patients could not be fitted and were not studied. The stocking chosen for this study avoids the problem of garters by means of a panel situated so that it interrupts the band at the top of the stocking and distributes the forces involved over a large area of the anterior thigh. (Figure 2.) Contrast medium (sodium diatrizoate), 50 ml, was rapidly injected into the greater saphenous vein at the ankle bilaterally and directed into the deep system by a tourniquet placed just proximal to the ankle. After injection, the tourniquets were immediately removed and a whole-leg
740
Figure 2. The elastic stocking used in this study; notice panel at the top.
roentgenogram was obtained to verify deep filling. This film was designated as time zero. Subsequent films were obtained at 5 minute intervals until all contrast had cleared on “wet” reading in the operating room. Patients known to be allergic to iodine and those with a history of venous disease or previous leg trauma were all excluded. The venograms were independently read by a colleague from the Department of Radiology who was unaware of the location of the experimental leg at the time he read the venogram. Results Fifteen patients (8 males, 7 females) were studied, ranging in ages from twenty to fifty-nine years (average, 37.1 years). The data are clearance times in minutes obtained by examination of the venograms described previously. Such data are not continuous; in fact, the
The American Journal of Surgery
Elastic Compression TABLE
Stockings
I Whole Leg Clearance Time in Minutes
Patient Stocking Control
-
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
15 20
15 30
10 20
15 25
10 20
20 25
20 45
25 40
20 30
20 45
15 50
20 35
20 20
25 50
25 25
18.3 32.0
Note: Paired ttest: degree of freedom, 14; observed t, 5.25;table value oft, 2.977 (p = 0.01).
precise time of disappearance of contrast from the deep veins is unknown and lies in the 5 minute interval between the last film on which contrast is seen and the subsequent film on which it cannot be seen. For the purpose of analysis a discrete value must be assigned. Either end or even the midpoint of this interval could be used without affecting the result. We have arbitrarily chosen the time of the last film on which contrast can be seen as the endpoint. Whole-leg clearance times are presented in Table I. The mean time observed in legs with stockings was 18.3 minutes which is *much better than the 32.0 minutes observed in the corresponding control legs. The difference, a striking 13.7 minutes, was tested using the paired t test and found to be highly significant (p = 0.01). Many studies examine only the calf and disregard the knee and thigh completely. To individually examine these areas, the venograms were read to provide clearance times for each of these positions separately. These data are presented in Table II along with the mean times and differences observed between the experimental and control legs for each of the positions. The significance of the differences observed was tested using a two-way analysis of variance (ANOVA). In the calf, contrast was cleared in 10.0 minutes from legs with stockings, which is 16.0 minutes faster than the 26.0 minutes in the corresponding control legs. This difference is highly significant (p = 0.01). Likewise, in the popliteal area clearance with stockings was 13.3 minutes whereas in control legs it was 20.0 minutes. The 7.7 minute difference is highly significant (p = 0.01). Finally, deep vein clearance in the thigh is seen to be better in experimental legs (16.7’minutes) than in control legs (26.7 minutes) and the difference (10.0 minutes) is highly significant (p = 0.01). Small differences observed between the three positions are not statistically significant. Comments
The venogram provides the only direct method of examination of blood flow in deep leg veins currently
Volume132,
December 1979
TABLE
II
Clearance Time in Minutes Popliteal
Thigh
___Calf ______~___ s C
S
c
s
c
2 3
15 10 10
20 25 30
0 15 20
10 15 20
0 5 10
0 30 20
4 5 6 7 8 9 10 11 12 13 14 15
15 10 15 20 25 20 10 15 20 20 20 25
25 20 25 20 40 30 15 50 35 20 20 25
10 0 20 15 20 10 20 10 15 5 15 25
25 0 25 25 20 30 20 15 15 20 35 25
0 5 0 15 20 15 15 10 10 15 25 5
15 15 0 45 40 10 45 50 30 15 50 25
Patient 1
16.7 26;7 13.3 20.0 Average 7.7 * 2.69 Difference 10.0 f 2.69 __Note: S = stocking;C = control.
10.0 26.0 16.0 c 2.69 ___-
available in that the areas of stagnation can be seen. Thus, the data presented herein show that stockings not only result in an increased velocity of venous flow in the legs, as Sigel et al [13] have confirmed, but also result in a more rapid clearance of stagnant blood from behind v,enous valves. We agree with Virchow’s original observation [14] that stagnation of blood in the veins is an important etiologic factor in the pathogenesis of deep vein thrombosis (DVT) and suggest that any technic that reduces stasis should result in a decreased incidence of DVT. Tsapogas et al [3] in a small but well controlled prospective study found a much reduced incidence of DVT over controls, using stockings, elevation, early ambulation, and passive exercises (iodine 125 [1251]-tagged fibrinogen uptake). Why then have some investigations of elastic compression based on the lz51-tagged fibrinogen uptake technic failed to show a decrease in DVT? Browse et al [IO] used “elastic stockings” on one leg while the other leg served as a control. Interestingly, the “stocking” they refer to is Tubegrip” elastic tubing (Figure 3) and not a stocking at all. Tubegrip is available in several sizes and weights. G4X is specified as the size used (shown on the right in Fig-
741
Lewis et al
ure 3). When cut in a suitable length, a cylindrical tube is produced. Such a tube when applied to a cylinder of proper dimensions would provide uniform compression. When applied to the leg, however, which is not cylindrical but an inverted cone, an inverse gradient is produced (tightest at the top). This could only impede flow from the leg rather than improve it. It is not surprising, therefore, that these “stockings” were ineffective in reducing DVT; on the
Figure 3. Tubegrip elastic tubing.
contrary, it is surprising that they did not result in a higher incidence of DVT. Rosengarten et al [9] also used this technic and their data are, therefore, also likely to be in error for the same reason. Other authors are sufficiently vague about the stocking technic employed to preclude more careful examination of their conclusions. No one, however, has stressed the critical importance of the fit previously*
Browse [IO] concludes that “stockings only result in a clearance of stagnant blood from behind the valve cusps whenever the pressure is so great that the veins are completely compressed.” Venograms studied herein and those reported earlier clearly refute this allegation. (Figure 4.) The stocking is on the right. Notice that the size of the venous channels on the right under the stockings are only slightly smaller than on the left. Contrast material subsequently cleared from the right leg in approximately half the time required in the control leg on the left, even from behind the venous valves which are clearly seen. With regard to the fit, Sigel et al [13] have previously shown that an optimal compression range is critical to venous flow velocity and that the compression must be applied in a decreasing gradient. Arnoldi [15], using an ingenious radiographic technic to measure flow velocity, has recently verified the results of Sigel et al [I31 and pointed out that during recumbency a much lighter compression is optimal. He was using the same stocking used in the present report. Finally, Ibraham, Scurr, and LeQuesne [16] have just reported a significant decrease in DVT diagnosed by i251-tagged fibrinogen using graded compression in carefully fitted stockings. Summary
Ffgure 4. Venogram with stocking on the right taken at 5 minutes. Note size of venous chanels.
742
The effect of elastic compression on venous flow in the legs provided by carefully fitted stockings has been measured by a venographic technic. The stocking used provides a gradually decreasing compression from ankle to groin. Clearance of stagnant blood from behind venous valves is clearly improved and the differences observed are statistically highly significant. These data suggest that the routine use of carefully fitted compression stockings will result in a decreased incidence of deep vein thrombosis (DVT) and provide a singularly safe, convenient, and noninvasive method of prophylaxis. Evidence presented suggests that at least two investigators have failed to show a decreased incidence of DVT in limbs subjected to elastic compression because the method of compression was inadequate.
The American Journal oi Surgery
Elastic Compression
Stockings
References
Discussion
1. Hunter WC, Sneeden VD, Robertson TD, Snyder GAG: Thrombosis of deep veins of leg; its clinical significance as exemplified in 351 autopsies. Arch Intern Med 68: 1, 1941. 2. Kakkar VV, Howe CT, Nicolaides AN, et al: Deep vein thrombosis of the leg. Is there a “high risk” group? Am J Surg 120: 527, 1970. 3. Tsapogas MJ, Miller R, Peabody RA. et al: Detection of postoperative venous thrombosis and effectiveness of prophylactic measures, studied with the fibrinogen 125-l technique. Arch Surg 101: 149, 1970. 4. McLachlin J, Paterson JC: Some basic observations on venous thrombosis and pulmonary embolism. Surg Gynecol Obstet 98: 1, 1951. 5. Eva& CM, Feil EJ: Prevention of thromboembolic disease after elective surgery of the hip. J Bone Joinf Surg 53A: 1271, 1971. 6. Flanc C, Kakkar VV, Clarke MB: The detection of venous thrombosis of the legs using 1251-labelled fibrinogen. Br J Surg 55: 742, 1968. 7. Flanc C, Kakkar VV, Clarke MB: Postoperative deep-vein thrombosis: effect of intensive prophylaxis. Lancet 1: 477, 1969. 8. Rosengarten DS, Laird J: The effect of leg elevation on the incidence of deep-vein thrombosis after operation. Br J Surg 58: 182, 1971. 9. Rosengarten DS, Laird J, Jeyasingh K, et al: The failure of compression stockings (Tubigrip) to prevent deep venous thrombosis after operation. Br J Surg 57: 296, 1970. 10. Browse NL, Jackson BT, Mayo ME, et al: The value of mechanical methods of preventing postoperative calf vein thrombosis. Br J Surg 61: 219, 1974. 11. McLachlin AD, Jackson BT, Mayo ME, Neggus D: Venous stasis in the lithotomy Trendelenberg position. Can JSurg 10: 414, 1967. 12. Lewis CE Jr, Mueller C, Edwards WS: Venous stasis on the operating table. Am J Surg 24: 780, 1972. 13. Sigel B, Edelstein AL, Savitch L, et al: Type of compression for reducing venous stasis. A study of lower extremities during inactive recumbency. Arch Surg 10: 171, 1975. 14. Virchow RLK: Beitr Exp Path 2: 227, 1846. Quoted by Jorpes JE: Heparin in the Treatment of Thrombosis, 2nd ed. London, Oxford University Press, 1946. 15. Arnoldi CC: Elastic compression in the prevention of deep venous thrombosis. Dan Med Bull 96: 221, 1976. 16. lbraham SZ, Scurr JH, LeQuesne LP: The effect of graded compression on the incidence of postoperative deep venous thrombosis. Presented before the 1 lth Congress, European Society of Surgical Research, Dublin, Ireland, April 27-30, 1976.
Larry Wilkinson (Albuquerque, NM): The employment of each patient as a control makes the results of this small series significant. These facts plus the objective methods of evaluation of venous emptying will result in this becoming a reference study for prophylaxis of venous complications. As the authors have demonstrated, the application of elastic supports may result in the garter effect any place along the extremity. Elastic supports also do not alter the flow through the pelvic veins. Consequently, after learning of the findings of this study, we have been trying another technic of venous emptying. Before making the incision and each 30 minutes thereafter the anesthetist turns the table into steep Trendelenberg position 30 seconds only. This provides the surgeon a pause and likely achieves adequate emptying of all the veins inferior to the heart. The concept that postoperative venous thrombosis begins while the patient is on the operating table is widely accepted. Prevention of this occurrence by whatever means will likely lower the incidence of serious postoperative embolic complications.
VobJmo132, Docembw IS76
Raymond C. Read (Little Rock, AR): Since good evidence recently that perhaps 40 per cent operative thrombi develop preoperatively, do the think that their stockings should be given to the when he or she reports to the surgical ward?
there is of postauthors patient
David B. Roos (Denver, CO): I would like to ask the authors if they have comparative studies for the belowknee stocking compared to the high thigh stocking and secondly, what is the name of the brand stocking he recommends. Charles E. Lewis, Jr (closing): We agree that the patient, particularly the patient who has been ill for some time and who is at bed rest prior to surgery, is well known to be in a higher risk group for this disease and I use these stockings in all those patients from the time they come on the ward until they are discharged. We chose this stocking (TED stocking) mainly because of the panel at the top and the very careful way these stockings were manufactured to provide the gradient that we were looking for. I prefer the long leg stocking.
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