continuous intravenous regional anesthesia

Acta anaesth. Scandinav. 1969, Supplementum XXXVI, 39-45.

C O N T I N U O U S I NTRAV E N 0 U S R E G I 0 NAL AN E S T H E S I A

BY

ELI M. BROWN, M. D.

Intravenous regional anesthesia has been established as a satisfactory technique in several series of patients and v~lunteersl-~. One of the limitations of the technique, however, has been the apparent necessity of constant inflation of the tourniquets*@. Because a tourniquet can remain inflated on an extremity for only a limited period of time (1 to ly2 hours) the technique, as described, was applicable only to surgical procedures which could be completed within thii time.

In prolonged surgery on the extremity, performed under tourniquet, it may be necessary to deflate and re-inflate the tourniquet several times during the course of the operation.

It occurred to us that if we could leave an indwelling catheter in place, we ought to be able to re-establish anesthesia by the simple expedient of in- jecting an additional quantity of anesthetic agent after reinflation of the tourniquet. We first attempted this technique in two relatively short surgical procedures in which the surgeon requested that we release the tourniquet prior to completion of the procedure so that he could control the bleeding with ligatures. When the anesthesia began to wane, the tourniquet was reinflated, half the original dose of lidocaine was injected and intense anesthesia was re-established. These experience encouraged us to attempt this continuous technique in a number of extensive and prolonged operations on the upper extremity.

The technique of continuous intravenous regional anesthesia is quite un- complicated. After raising a skin wheal, an indwelling polyethelene catheter is placed in a suitable vein sufficiently far removed from the operative site so that it will not interfere with the sterile surgical field. The catheter is attached to an intravenous solution containing 500 cc of 5% dextrose in water. The tubing should be of sufficient length to make it convenient for the anesthesio- logists to inject the local anesthetic agent whenever necessary during the procedure without encroaching upon the sterile field. The intravenous catheter and tubing is securely fastened so that it will not become dislodged during the surgical procedure.

Chief, Division of Anesthesiology, Sinai Hospital of Detroit, Detroit, Michigan, U.S.A.

40 ELI M. BROWN

A double tourniquet technique is employed to prevent the pain which might result from the prolonged inflation of a single tourniquet over an un- anesthetized area. The particular equipment which we use encompasses two tourniquets within a single cuff. Each tourniquet is attached to a separate inflating mechanism by means of a non-slip luer-lok connector. The cuff is placed securely on the upper arm but not so tightly as to impede venous drainage.

The extremity is raised and held for a period of three minutes so that blood may drain from the extremity by gravity. In order to assure complete exsanguination of the extremity, an Esmarch bandage is applied from the patient’s finger tips to the distal end of the tourniquet.

With the Esmarch bandage in place, the proximal tourniquet is inflated to 250 mm Hg pressure. After checking the tourniquet to be certain that it is fully inflated, the Esmarch bandage is removed.

For the average patient 40 cc of 0.5% lidocaine is administered intravenously distal to the inflated tourniquet. Patients with very large arms may require as much as 50 cc. For patients with slender arms, or children, the dose is decreased proportionately. After allowing three to five minutes for the anesthetic to become complete, the distal tourniquet is inflated to 250 mm Hg pressure and the proximal tourniquet is deflated. Since the area beneath the distal tourniquet has become anesthetized along with the rest of the extremity beyond the tourniquet, the patient should not experience any pain.

The surgeon then proceeds to prepare his patient. When the surgical procedure has been underway for approximately one hour, the surgeon is asked to choose a convenient time for deflation of the tourniquet. When this convenient point is reached, the distal tourniquet is deflated and oxygenated blood enters the extremity. The surgeon ligates any large bleeders which may be present. When the tourniquet has been deflated for approximately ten minutes the surgeon applies a sterile Esmarch bandage as far proximally as possible within the confines of the sterile field and the distal tourniquet is reinflated. After inflation of the tourniquet y2 of the original dose of 0.5% lidocaine (20 cc for the average patient) is injected through the intravenous catheter which has been kept patent with a very slow drip of 5% dextrose in water.

The surgeon may then continue to work for approximately another hour. At the end of this time, the procedure is repeated with one frequent exception. It is frequently not necessary to inject additional anesthetic agent after this second reinflation of the tourniquet. If the patient complains of discomfort we recommend injection of an additional 10 to 15 cc of 0.5% lidocaine. At the end of the operative procedure, the distal tourniquet is deflated provided that the elapsed time from the last injection of the anesthetic agent is not less than 45 minutes. The time from the final deflation of the tourniquet to return of sensation varies, but it has not exceeded 30 minutes in any of our cases.

CONTINUOUS INTRAVENOUS REGIONAL ANESTHESIA 41

RESULTS

We have employed continuous intravenous regional anesthesia for major reconstructive surgery of the upper extremity a total of 6 times in four patients. The age and sex of these patients, the operative procedure and the duration of surgery appear in table 1.

Five of these cases involved multiple operative procedures, quite extensive in nature. These operations required intense anesthesia of the extremity for the entire duration of the procedure. The sixth case involved the single procedure of resection of the distal ulna, somewhat shorter in duration than the others but still requiring intense anesthesia. Table 2 shows the duration of anesthesia, the number of times the tourniquet was deflated during the procedure, the dosage of lidocaine administered after each inflation, and the total dose in volume and milligrams.

The double figures in case number 3 (table 2) are placed there to indicate that approximately 20 cc of the total dose was injected extravascularly as a result of an error in technique. In this case, the intravenous catheter was dislodged during the surgical preparation. Since the initial dose of anesthetic had been injected, the first part of the procedure went smoothly. After 1% hours when the tourniquet was deflated, we had difficulty in finding another

Table 1.

Name 1 Age I Operation Durationof Surgery

J.C. 38 M 1. Amputation right thumb 3 hrs 45 min

I.E. 59 M 1. Synovectomy dorsal compartment 3hrs5min

2. Pollicization of Index Finger

2. Resection Distal Ulna 3. Fusion I-P Joint of Thumb 4. Tendon transfers

I.E. 59 M 1. Synovectomy of 4 fingers M-P Joint 3 hrs 40 min

E.M. 62 M 1. Resection distal 1/2 ulna left 2 hrs 45 min

2. Tendon transfer of index finger

2. Arthroplasty 2nd, 3rd, 4th, 5th M-P Joints 3. Tendon transfer ext. Indicis Propius 4. Arthrodesis of ring and middle finger proximal

IP joints

E.M. 62 M 1. Resection distal ulna right 2 hrs 35 min 2. Arthroplasties 2, 3, 4, 5 M-P joints 3. Tendon transfer ext. Indicis Propius 4. Arthrodesis 4, 5 proximal IP Joints

W.R. 27 M 1. Section distal portion of ulna 2 hrs 5 min

42

Total time of Ann. Tourn.

Hrs I Min 1 ELI M. BROWN

Dosage of 0.5% Xylocaine

1 I 2 1 3

Total Mg

TABLE 2.

Name

J.C ........... 4 3 3 50 20 10 80 400 ......... 60 300 I.E.. 3 42 3 40 20 -

475 - 95 - 20 ......... l 5 75 375

- 40 20

I.E.. 3 5 3

........ 60 300 E.M.. 3 20 3 40 20 - .......... 60 300 E.M 3 - 2 40 20 -

........ 60 300 W.R.. 2 15 2 40 20 -

TABLE 3. Plasma level of lidocaine (Mcglml)

Single Dose

Deflated at 50 Minutes

(200 mpm)

Continuous (Total Dose 475 mgm)

Release.. ..................... 0.6 Release + 5 Minutes. . . . . . . . . . . 1.1 Release + 10 Minutes. . . . . . . . . . 1.1 Release + 30 Minutes. ......... 1.3

0.5 0.8 1 . 1 0.9 2.1 1.4 0.7 1.5 1.4 - - 1.2

suitable vein and the subsequent dose of local anesthetic infiltrated. The problem was solved by having the surgeon insert a needle into a small vein in the operative field. Excellent anesthesia was re-established and the operation continued without further difficulty. This experience taught us the importance of adequately securing our intravenous catheter and isolating it from the field during the surgical preparation.

It should be noted that the total dose administered is somewhat larger and in some cases double the maximum safe dose recommended by some authors for single dose techniques'. 3. We thought it prudent, therefore, to measure blood levels in 2 of our cases and to compare them with blood levels obtained during a single dose technique. Table 3 lists the blood levels obtained in a typical single dose technique as compared to those obtained in a continuous technique. Except for the level of 2.1 mcg/ml obtained five minutes after the second deflation, the values are similar. The most significant point to be made, however, is that despite the large doses which we used, we did not see either subjective or objective symptoms of toxicity in any of these patients. The blood pressure and pulse remained remarkably stable throughout the procedure and in the immeditate postoperative period. Each of these patients


had excellent anesthesia for the entire duration of the prolonged operative procedure. Since the patients were required to remain immobile for a long period of time, we occasionally used small doses of barbiturate and narcotic to make them comfortable. It should be noted, however, that in each instance the patient was awake and able to converse coherently throughout the operation.

COMMENTS

Our experience with these few cases, and a much larger experience using the single dose technique, has led us to a number of observations and raised some questions concerning the technique of intravenous regional anesthesia.

In contrast to the findings of SORBIE and CHACHA~ we have noted, as have others497 that the injection of the anesthetic agent into a proximal forearm vein or antecubital vein does not delay the onset of anesthesia, nor does it decrease its efficiency, provided an adequate dose of anesthetic agent is employed. If one uses an initial dose of 40 cc of 0.5 yo lidocaine, the site of injection is unimportant and the results are uniformly good. Furthermore, it is not necessary to inflate the tourniquet for twenty minutes prior to injection of the local anesthetic as recommended by BELL et al.s.

The question of toxicity has arisen when using these doses of lidocaine. It is interesting to note that in the great majority of cases in which toxic reactions have been reported, the tourniquet was deflated within a half hour after injection of the anesthetic agent. In the series of cases reported by KENNEDY in which 7 of 77 patients developed toxic symptoms, the average time from injection of the anesthetic to deflation of the tourniquet was 26% minutes. In contrast, in a series of over 60 cases in which we used the single dose technique, as well as in the 6 cases of continuous anesthesia reported here, we have observed no toxic reactions.

This absence of toxicity is particularly significant in our cases of continuous anesthesia because we were administering total dosages in the range of 300 to 400 mgm. We attribute the lack of toxic reactions in our series of cases to the fact that regardless of when surgery is completed the tourniquet is never deflated until a period of 45 minutes to 1 hour has elapsed from the time of the last injection of anesthetic agent. In the great majority of cases, this poses no problem since even in very short cases, the combined time of preparation, surgery, and application of the dressing usually falls withiin this limit. In one or two instances in which this was not the case, we took the patient to the recovery room with the tourniquet in place and did not release it until the required time period had elapsed.

The fact that toxic reactions did not occur even with these large doses indicates that a large part of the anesthetic agent had become fixed in the tissues and was absorbed into the circulation at a very slow rate as suggested

44 ELI M. BROWN

by HARGROVE et al.Q and Coxlo. It is likely that the percentage of drug which becomes distributed in the tissues is related to the length of time during which the tourniquet is inflated. This hypothesis would account for the lack of toxic reactions. It would also explain the observation that the longer the tourniquet remains inflated, the longer the period of analgesia following deflation. In these cases of continuous analgesia, our surgeons were able to work for as long as 15 minutes following deflation of the tourniquet. Furthermore, we noted that it was not necessary to use the double tourniquet technique during subsequent injections, indicating that there was some degree of residual anesthesia in the area of the arm beneath the distal tourniquet. Finally, the presence of sufficient local anesthetic agent in the tissues would explain the fact that it was not necessary to inject additional lidocaine at the third inflation of the tourniquet in 4 of our cases. It would be interesting to measure tissue levels of lidocaine in the anesthetized extremity in order to ascertain the level at which anesthesia ensues and the level at which sensation returns.

The question naturally arises as to the role of ischemia in this process. It has been shown that ischemia alone does not account for the anesthesia observed during single dose intravenous regional anesthesiall. However, ischemia may contribute to the prolongation of the anesthesia. BELL has suggested that the decrease in 0, tension, the increase in pC0, and the altered pH which result from ischemia, may potentiate the action of the local anesthetic3. We have observed that, when the tourniquet is deflated at the end of even a prolonged surgical procedure, sensation returned within a period of time which did not exceed thirty minutes, but if the tourniquet was reinflated during this time, anesthesia was present even after one hour. What is the significance of this observation? Is anesthesia maintained simply by the trapping of sufficient residual anesthetic agent within the extremity or is it the re-establishment of anerobic conditions which is primarily reponsible for prolongation of the anesthetic? These are question which need to be answered.

Be that as it may, from the viewpoint of the clinician it appears that intravenous regional anesthesia, single dose or continuous, is an extremely valuable technique. It is easy to learn, very reliable and highly acceptable to patients. Furthermore, the technique is reasonably safe provided that sufficient time is allowed to elapse between the injection of the drug and deflation of the tourniquet.

REFERENCES

1 . HOLMES, C. McK.: Intravenous regional analgesia: a useful method of producing

2. SORBIE, C., and CHACHA, P.: Regional anaesthesia by the intravenous route. Brit.

3. BELL, H. M., SLATER, E. M., and HARRIS, W. H.: Regional anesthesis with intravenous

analgesis of the limbs. Lancet, 1:245, 1963.

Med. J., 1:957, 1965.

lidocaine. J.A.M.A., 186:544, 1963.


4. ADAUS, J. P., DEALY, E. J., and KENMORE, P. I.: Intravenous regional anesthesia in hand surgery. J. Bone Joint Surg., 46A:811, 1964.

5. ATKINSON, D. I., MODELL, J., and MOYA, F. : Intravenous regional anesthesia. Anesth. Analg., 44:313, 1965.

6. KNAPP, R. B.: Intravenous regional anesthesia of the upper extremity. Anesth. Analg., 44:302, 1965.

7. MONTY, C. P., and DELLER, C. R.: Experiences with intravenous regional anaesthesia. Proc. Roy. SOC. Med., 58:338, 1965.

8. KENNEDY, B. R., DUTHIE, A. M., and PARBROOK, G. D., and CARR, T. L.: Intravenous regional analgesia: an appraisal. Brit. Med. J. 1:954, 1965.

9. HARGROVE, R. L., HOYLE, J. R., PARKER, J. B., BECKETT, A. H., and BOYES, R. N.: Blood lignocaine levels following intravenous regional analgesia. Anaesthesia, 21 :37, 1966.

10. Cox, M. J.: Intravenous regional anaesthesia. Canad. Anaes. SOC. J., 11:503, 1964. 11. MILES, D. W., JAMES, J. L., CLARK, D. E., and WHITWAM, J. G.: Site of action of

intravenous regional anaesthesia. J. Neurol. Neurosurg. Psychiat. 27:574, 1964.

continuous intravenous regional anesthesia

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