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Intraoperative assessment of limb revascularization by Doppler-derived segmental blood pressure measurements
lntraoperative Assessment of Limb Revascularization by DopplerDerived Segmental Blood Pressure Measurements
Larry R. Williams, MD, Chicago, Illinois D. Preston Flanigan, MD, Chicago, Illinois James J. Schuler, MD, Chicago, Illinois Leonardo T. Lim, MD, Chicago, Illinois
Recent reports have documented the usefulness of intraoperative assessment of revascularization procedures on the lower extremities [l-8]. Since technical factors are often responsible for early graft failure, some convenient means for determining the functional adequacy of a procedure in the operating room are necessary. An intraoperative approach would allow for prompt correction of any error and would eliminate the additional morbidity associated with early reoperation. Simple clinical measures, such as increased warmth, capillary refill, and return of distal pulses are grossly inadequate for determining hemodynamic function. Variations in clinical findings are seen with type and depth of anesthesia, multisegmental arterial occlusive disease, associated skin conditions, body temperature, and methods of prepping and draping. Inspection and palpation of the vessels proximal and distal to the anastomosis can be useful, but are often misleading since pulsation is sometimes seen with completely thrombosed vessels or grafts. Pulsations may also be present initially when inadequate inflow or significant outflow obstruction causes functional failure of a bypass. Intraoperative arteriography is’ a standard means for determining the adequacy of an infrainguinal bypass procedure. The limitation of this method is that it is a purely anatomic assessment and does not provide hemodynamic data. Recent advances using pulse volume recorders [l-4], segmental [5] and digital plethysmography [2], electromagnetic flow devices [6], and direct pressure determinations [5] provide hemodynamic measurements but involve cumbersome or expensive equip-
From the Division of Vascular Surgery, Department of Surgery, Abraham Lincoln School of Medicine, University of Illinois Medical Center, Chicago, Illinois. Requests for reprints should be addressed to D. Preston Flanigan, MD, Division of Vascular Surgery, Department of Surgery, University of Illinois Medical Center, P.O. Box 6998, Chicago, Illinois 60880.
578
ment and are often time consuming. A system that simplifies the intraoperative hemodynamic assessment of revascularization procedures is presented. Technique
Patients about to undergo lower extremity revascularization are prepped and draped routinely to include the feet in the sterile field. The planned procedure is carried out and, before closure of the wounds, systolic blood pressure measurements are determined at the ankle. For aortoileo-femoral bypass procedures systolic pressure measurements at the lower thigh are also occasionally required. The technique employs a pneumatic cuff with a 10 by 17 cm inflatable bladder (17 by 64 cm for lower thigh measurement) and a 9.5 MHz Doppler pencil probe which has been previously gas sterilized. The connecting wires for the pencil probe are kept off the sterile field and connected to a Doppler flow detector with speaker output (Parks model 811, Parks Electronics Lab, Beaverton, OR), and the pneumatic cuff is connected to a mercury column sphygmomanometer (Figure 1). Lower extremity blood pressures are then determined in standard fashion. This equipment provides a convenient., audible output for blood pressure measurements and allows calculation of ankle/arm and thigh/arm pressure indices. Comments
Intraoperative determination of success or failure of any revascularization procedure is an important aspect of proficient patient care. If technical errors that may jeopardize an operation’s outcome can be identified and corrected in the operating room, the patient is saved from the increased morbidity associated with early reoperation. This morbidity takes the form of additional anesthetic time, sometimes with multiple types of anesthetic agents and their associated complications, lengthy secondary procedures with increased propensity for ischemic tissue damage and wound infection, and the psychologic burden on the patient which accompanies reopera-
The American
Journal of Surgery
Assessment
tion. At times, unavoidable delays between operation and reoperation prolong ischemia in limbs that are already at risk. .4lthough intraoperative arteriography provides important anatomic information concerning the status of the anastomosis, the graft itself, and the distal runoff, it does not assess hemodynamic function. It is well documented that noninvasive segmental blood pressure measurements by Doppler ultrasound are a more sensitive indication of hemodynamically significant arterial stenoses than arteriography 191.This does not imply that intraoperative measurements by Doppler ultrasound replace angiography after operation, but that together they act in conjunction to supply the surgeon with hemodynamic as well as anatomic information. The systemic changes in peripheral vascular resistance, blood volume, and cardiac output that are seen during anesthesia with different types of anesthetic agents may have an effect on ankle/arm systolic pressure indices; however, quantitation of this effect has not been documented. Immediately after a bypass is completed, ankle/arm indices seem to be reliable predictors of later postoperative indices after infrainguinal procedures. A common problem with more proximal bypasses, especially when concomitant distal arterial occlusive disease is present, is that the initial ankle/arm index is much lower than expected, but within the several hours after operation, the index rises to a consistent reading. The low thigh/arm pressure index, however, is more reliable immediately after suprainguinal procedures since the value appears to be consistent in the later postoperative course. There are several specific advantages to intraoperative measurement of blood pressure with the Doppler flow detector. It can be carried out without additional expensive equipment. The materials employed are commonly available and already in use, obviating the added cost of strain gauge plethysmography [2,3], flow probes, and flow meters [6], pulse volume recorders [3], and pressure transducers [5]. Also, since the surgeon is in control of the determination there is no need to rely on the availability of tramed personnel or inexperienced circulating nurses to make the intraoperative assessment. Another advantage of this technique is the ability to measure Doppler indices at any time after completion of the anastomoses, allowing comparison bef:,re and after wound closure if any change suggests compromise of the bypass. There is no need to incorporate nonsterile equipment into the initial prepping and draping of the patient or to cause contamination during the operation. Previous reports have described an inability to measure pressures intraoperatively in femoropopliteal or more distal bypasses because of interference with the sterile field [8]. Distal extremity incisions in no way limit the use of the sterilized blood pressure cuffs and probes. This
Volume 144, November 1982
of Limb Revascularization
Figure 1. Technique for intraoperative blood pressure measurement using the Doppler flow detector.
aspect will assume greater importance distal bypass procedures increases.
as use of more
Summary Prompt recognition and correction of technical errors in vascular procedures in the lower extremities decreases patient morbidity and improves the chances for successful revascularization. A simple, versatile technique for intraoperative hemodynamic assessment of lower extremity revascularization procedures is described. Salient features include ability to detect and correct technical errors without reoperation and its associated morbidity, use of commonly available, inexpensive equipment, and ease of performance without involvement of either specifically trained or inexperienced personnel.
References 1. Garrett WV, Slaymaker EE, Heintz SE, Barnes RW. lntraoperative operative prediction of symptomatic result of aortofemoral bypass from changes in ankle pressure index. Surgery 1978;82:504-9. 2. Strandness DE, Bell JW. Peripheral vascular disease: diagnosis and objective evaluation using a mercury strain gauge. Ann Surg 1965;161(suppl):3-35. 3. O’Donnell TF, Raines JK, Darling RC. lntraoperative monitoring using the pulse volume recorder. Surg Gynecol Obstet 1977;145:252-4. 4. Plume SK, DeWeese JA, Slomczewski CM. lntraoperative assessment of peripheral revascularization procedures. Surg Gynecol Obstet 1976; 142:43. 5. Griffin LH, Wray Cl-t, Vaughn BL, Moretz WH. Detection of vascular occlusions during operation by segmental plethysmography and skin thermometery. Ann Surg 1971; 173:38997. 6. Mannick JA, Jackson BT. Hemodynamics of arterial surgery in atherosclerotic limbs. I. Direct measurement of blood flow before and after vein grafts. Surgery 1966;59:713-20. 7. Barnes RW. Garrett WV. lntraoperative assessment of arterial reconstruction by Doppler ultrasound. Surg Gynecol Obstet 1978;146:896-900. 8. Mozersky DJ, Sumner DS, Barnes RW, Strandness DE. Intraoperative use of a sterile ultrasonic flow probe. Surg Gynecol Obstet 1973;136:279-80. 9. Bone GE, Hayes AC, Slaymaker EE, Barnes RW. Value of segmental limb blood pressure in predicting results of aortofemoral bypass. Am J Surg 1976;132:733-8.
579
Larry R. Williams, MD, Chicago, Illinois D. Preston Flanigan, MD, Chicago, Illinois James J. Schuler, MD, Chicago, Illinois Leonardo T. Lim, MD, Chicago, Illinois
Recent reports have documented the usefulness of intraoperative assessment of revascularization procedures on the lower extremities [l-8]. Since technical factors are often responsible for early graft failure, some convenient means for determining the functional adequacy of a procedure in the operating room are necessary. An intraoperative approach would allow for prompt correction of any error and would eliminate the additional morbidity associated with early reoperation. Simple clinical measures, such as increased warmth, capillary refill, and return of distal pulses are grossly inadequate for determining hemodynamic function. Variations in clinical findings are seen with type and depth of anesthesia, multisegmental arterial occlusive disease, associated skin conditions, body temperature, and methods of prepping and draping. Inspection and palpation of the vessels proximal and distal to the anastomosis can be useful, but are often misleading since pulsation is sometimes seen with completely thrombosed vessels or grafts. Pulsations may also be present initially when inadequate inflow or significant outflow obstruction causes functional failure of a bypass. Intraoperative arteriography is’ a standard means for determining the adequacy of an infrainguinal bypass procedure. The limitation of this method is that it is a purely anatomic assessment and does not provide hemodynamic data. Recent advances using pulse volume recorders [l-4], segmental [5] and digital plethysmography [2], electromagnetic flow devices [6], and direct pressure determinations [5] provide hemodynamic measurements but involve cumbersome or expensive equip-
From the Division of Vascular Surgery, Department of Surgery, Abraham Lincoln School of Medicine, University of Illinois Medical Center, Chicago, Illinois. Requests for reprints should be addressed to D. Preston Flanigan, MD, Division of Vascular Surgery, Department of Surgery, University of Illinois Medical Center, P.O. Box 6998, Chicago, Illinois 60880.
578
ment and are often time consuming. A system that simplifies the intraoperative hemodynamic assessment of revascularization procedures is presented. Technique
Patients about to undergo lower extremity revascularization are prepped and draped routinely to include the feet in the sterile field. The planned procedure is carried out and, before closure of the wounds, systolic blood pressure measurements are determined at the ankle. For aortoileo-femoral bypass procedures systolic pressure measurements at the lower thigh are also occasionally required. The technique employs a pneumatic cuff with a 10 by 17 cm inflatable bladder (17 by 64 cm for lower thigh measurement) and a 9.5 MHz Doppler pencil probe which has been previously gas sterilized. The connecting wires for the pencil probe are kept off the sterile field and connected to a Doppler flow detector with speaker output (Parks model 811, Parks Electronics Lab, Beaverton, OR), and the pneumatic cuff is connected to a mercury column sphygmomanometer (Figure 1). Lower extremity blood pressures are then determined in standard fashion. This equipment provides a convenient., audible output for blood pressure measurements and allows calculation of ankle/arm and thigh/arm pressure indices. Comments
Intraoperative determination of success or failure of any revascularization procedure is an important aspect of proficient patient care. If technical errors that may jeopardize an operation’s outcome can be identified and corrected in the operating room, the patient is saved from the increased morbidity associated with early reoperation. This morbidity takes the form of additional anesthetic time, sometimes with multiple types of anesthetic agents and their associated complications, lengthy secondary procedures with increased propensity for ischemic tissue damage and wound infection, and the psychologic burden on the patient which accompanies reopera-
The American
Journal of Surgery
Assessment
tion. At times, unavoidable delays between operation and reoperation prolong ischemia in limbs that are already at risk. .4lthough intraoperative arteriography provides important anatomic information concerning the status of the anastomosis, the graft itself, and the distal runoff, it does not assess hemodynamic function. It is well documented that noninvasive segmental blood pressure measurements by Doppler ultrasound are a more sensitive indication of hemodynamically significant arterial stenoses than arteriography 191.This does not imply that intraoperative measurements by Doppler ultrasound replace angiography after operation, but that together they act in conjunction to supply the surgeon with hemodynamic as well as anatomic information. The systemic changes in peripheral vascular resistance, blood volume, and cardiac output that are seen during anesthesia with different types of anesthetic agents may have an effect on ankle/arm systolic pressure indices; however, quantitation of this effect has not been documented. Immediately after a bypass is completed, ankle/arm indices seem to be reliable predictors of later postoperative indices after infrainguinal procedures. A common problem with more proximal bypasses, especially when concomitant distal arterial occlusive disease is present, is that the initial ankle/arm index is much lower than expected, but within the several hours after operation, the index rises to a consistent reading. The low thigh/arm pressure index, however, is more reliable immediately after suprainguinal procedures since the value appears to be consistent in the later postoperative course. There are several specific advantages to intraoperative measurement of blood pressure with the Doppler flow detector. It can be carried out without additional expensive equipment. The materials employed are commonly available and already in use, obviating the added cost of strain gauge plethysmography [2,3], flow probes, and flow meters [6], pulse volume recorders [3], and pressure transducers [5]. Also, since the surgeon is in control of the determination there is no need to rely on the availability of tramed personnel or inexperienced circulating nurses to make the intraoperative assessment. Another advantage of this technique is the ability to measure Doppler indices at any time after completion of the anastomoses, allowing comparison bef:,re and after wound closure if any change suggests compromise of the bypass. There is no need to incorporate nonsterile equipment into the initial prepping and draping of the patient or to cause contamination during the operation. Previous reports have described an inability to measure pressures intraoperatively in femoropopliteal or more distal bypasses because of interference with the sterile field [8]. Distal extremity incisions in no way limit the use of the sterilized blood pressure cuffs and probes. This
Volume 144, November 1982
of Limb Revascularization
Figure 1. Technique for intraoperative blood pressure measurement using the Doppler flow detector.
aspect will assume greater importance distal bypass procedures increases.
as use of more
Summary Prompt recognition and correction of technical errors in vascular procedures in the lower extremities decreases patient morbidity and improves the chances for successful revascularization. A simple, versatile technique for intraoperative hemodynamic assessment of lower extremity revascularization procedures is described. Salient features include ability to detect and correct technical errors without reoperation and its associated morbidity, use of commonly available, inexpensive equipment, and ease of performance without involvement of either specifically trained or inexperienced personnel.
References 1. Garrett WV, Slaymaker EE, Heintz SE, Barnes RW. lntraoperative operative prediction of symptomatic result of aortofemoral bypass from changes in ankle pressure index. Surgery 1978;82:504-9. 2. Strandness DE, Bell JW. Peripheral vascular disease: diagnosis and objective evaluation using a mercury strain gauge. Ann Surg 1965;161(suppl):3-35. 3. O’Donnell TF, Raines JK, Darling RC. lntraoperative monitoring using the pulse volume recorder. Surg Gynecol Obstet 1977;145:252-4. 4. Plume SK, DeWeese JA, Slomczewski CM. lntraoperative assessment of peripheral revascularization procedures. Surg Gynecol Obstet 1976; 142:43. 5. Griffin LH, Wray Cl-t, Vaughn BL, Moretz WH. Detection of vascular occlusions during operation by segmental plethysmography and skin thermometery. Ann Surg 1971; 173:38997. 6. Mannick JA, Jackson BT. Hemodynamics of arterial surgery in atherosclerotic limbs. I. Direct measurement of blood flow before and after vein grafts. Surgery 1966;59:713-20. 7. Barnes RW. Garrett WV. lntraoperative assessment of arterial reconstruction by Doppler ultrasound. Surg Gynecol Obstet 1978;146:896-900. 8. Mozersky DJ, Sumner DS, Barnes RW, Strandness DE. Intraoperative use of a sterile ultrasonic flow probe. Surg Gynecol Obstet 1973;136:279-80. 9. Bone GE, Hayes AC, Slaymaker EE, Barnes RW. Value of segmental limb blood pressure in predicting results of aortofemoral bypass. Am J Surg 1976;132:733-8.
579