REGIONAL ANESTHESIA AND PAIN MANAGEMENT SECTION EDITOR DENISE J. WEDEL The Effect of Lithotomy Position on Arterial Blood Pressure After Spinal Anesthesia Masayuki Miyabe, MD*, Hajime Sonoda, MD*, and Akiyoshi Namiki, MDt *Department of Anesthesia, Kushiro General City Hospital, Kushiro, Japan, and I-Department of Anesthesiology, Sapporo Medical University, School of Medicine, Sapporo, Japan. We compared the effect of the lithotomy position on the 16% at 5 min and continued to decrease to 21%. The systolic blood pressure (SBP) with the horizontal posi- extent of the cephalad spread of analgesia 20 min after tion after spinal block. The lithotomy position was per- spinal block was same between the two groups (T-5 ? 2 formed 5 min after spinal block. The change in SBP was vs T-5 -C 2, respectively). From these results we con- expressed as percent of depression from the baseline clude that the lithotomy position after spinal anesthesia value. The SBP increased by the lithotomy position (n = attenuates the decrease in arterial blood pressure and 14) from a 16% decrease to an 8% decrease. On the con- does not affect the cephalad spread of analgesia. trary, in the horizontal group (n = 14), SBP decreased (Anesth Analg 1995;81:96-8) light head-down tilt is one of the treatments of the right lateral position on a horizontal table. Based S hypotension after spinal anesthesia to increase venous return and cardiac output (1,2). Similar to head-down tilt, the lithotomy position may also in- on the patient’s height (5155 cm, 2.5 mL; ~155 cm, 3 mL), 0.5% tetracaine dissolved in 10% glucose was injected at a rate of 0.2 mL/s. After subarachnoid crease venous return and cardiac output after spinal injection, patients were immediately turned to the su- block. The purpose of this study is to investigate pine position. All patients received an infusion of whether the lithotomy position affects the systemic lactated Ringer’s solution at a rate of 10 mL/min blood pressure (SBP) and analgesic level after spinal started before lumbar puncture and continued during block. the study. The SBP was measured before the patient was po- Methods sitioned for lumbar puncture and every 1 min after injection of the anesthetic with an automated nonin- The protocol of this study, which was approved by vasive blood pressure device (BP-380 ET; Nippon Co- our ethics committee, was explained and each pa- lin Co., Ltd., Tokyo, Japan). Cephalad extent of anal- tient’s consent was obtained. The study was con- gesia was assessedat 5-min intervals for 20 min after ducted on 28 female patients, ASA physical status I, injection. Analgesia was defined as the inability to aged 28 - 61 yr, undergoing major elective gynecologic sense pinprick. surgery (abdominal hysterectomy in the horizontal Fourteen patients were placed in the lithotomy po- group and transvaginal hysterectomy in the lithotomy sition 5 min after injection of local anesthetic (lithoto- group). Patients being treated for high or low blood my group). The other 14 patients were maintained in pressure or receiving any other medications that could the horizontal position (horizontal group). The trends affect arterial blood pressure or heart rate were ex- of change in the SBP and cephalad spread of analgesia cluded from this study. were compared between the two groups. The change One hour before operation the patients were given in SBP was expressed as percent of depression from 2.5-5 mg of midazolam and 0.5 mg of atropine intra- the baseline value. muscularly. A standard midline lumbar puncture was Data were expressed as mean + SD. The patient performed using a 25-gauge needle through the L3-4 characteristics between the groups were compared by interspace. All lumbar punctures were performed in Student’s t-test. The differences in SBP with or without the lithotomy position were compared by repeated- Accepted for publication February 10, 1995. measures analysis variance (two-way analysis of vari- Address correspondence and reprint requests to Masayuki Miyabe, MD, The Department of Anesthesiology, Institute of Clin- ance). As post hoc test the SBP changes from value of ical Medicine, University of Tsukuba, Tsukuaba 305, Japan. 5 min after spinal block were compared with Fisher’s 01995 by the International Anesthesia Research Society 96 Anesth Analg 1995;81:96-8 0003.2999/95/$5.00 ANESTH ANALG REGIONAL ANESTHESIA AND PAIN MANAGEMENT MIYABE ET AL. 97 1995;81:96-8 LITHOTOMY, ARTERIAL BLOOD PRESSURE, AND SPINAL ANESTHESIA Table 1. Clinical Characteristics of the Horizontal and time after spinal block (min) Lithotomy Groups -2 baseline 1 5 10 15 20 1 I I I I I Horizontal Lithotomy jj+lO - + horizontal 2 lithotomy -A- lithotomy No. 14 14 39 -c 6 45 ? 5* If o- Age (yr) z (2849) (41-61) n Weight (kg) 53 -c 7 56 t 5 ii -10 - (43-67) (47-65) z Height (cm) 155 t 5 155 -c 7 til (149-165) (146-166) c -20 - Tetracaine (mg) 13.4 + 1.2 13.4 ? 1.3 z 511 (12.5-15) (12.5-15) ;s i 55 5 8 -30 - Analgesic level after spinal block 5 min T-9 I- 2 T-9 -c 2 Figure 1. The time sequence of systolic blood pressure (SBP) change after spinal block with (n = 14) or without (n = 14) the (Tll-6) (T12-5) lithotomy position. The lithotomy position was performed 5 min 10 min T-7 t 2 T-7 +- 1 after spinal block. Data are mean f SD. +P < 0.01, *SrP < 0.05 (Tll-5) (T9-5) compared with the value of the horizontal group. “P < 0.05, **P < 15 min T-6 t 2 T-7 k 1 0.01 compared with the 5 min value of the lithotomy group. §P < (T9-4) (T7-2) 0.01, @P < 0.05 compared with the 5 min value of the horizontal 20 min T-5 -c 2 T-5 ‘-’ 2 group. (T9-3) (T8-2) Values are mean t SD, with the range given in parentheses. normal persons (4-6) as well as in spinal-anesthetized * P < 0.01 vs horizontal group. patients (4,7), blood pressure response after head- down tilt varies. Compared to head-down tilt, the effect of the lithotomy position in this study seems to protected least significant difference test. Nonpara- be greater and consistent. Several factors may be re- metric analysis (Mann-Whitney U-test) was used to sponsible for the differences. compare the analgesic levels. A P value of less than First, the autotransfusion effect may be greater in 0.05 was considered to be significant. the lithotomy than in the head-down tilt position. The reason blood pressure increases after placing the pa- Results tient into the Trendelenburg or the lithotomy position is explained by the return of the pooled venous blood The mean age in the lithotomy group was higher than from the lower extremities (500-1000 mL) to the heart in the horizontal group (Table 1). There were no sta- (autotransfusion effect) (1). In this study, the standard tistically significant differences in mean weight, lithotomy position was used; both thighs were lifted height, and cephalad spread of analgesia between the 90” toward the trunk and the lower legs were hung on lithotomy and the horizontal groups. poles with ties. In this position the highest point The total volume of lactated Ringer’s solution in- (knees) may be approximately 40 cm above the heart fused during study was 50 mL before spinal block and (depending on the individual thigh length), whereas 200 mL after block in both groups. In both groups the in a 10” head-down tilt position the highest point is at average SBP, 5 min after spinal block, decreased 16% the feet and which is only approximately 15-20 cm from baseline. In the lithotomy group, SBP increased above the heart (depending on the individual height). to 8% depression level and maintained at 8%-13% Therefore it is likely that the increase in venous return depression level for the entire study period (Fig. 1). was greater in the lithotomy than in head-down tilt On the contrary in the horizontal group, SBP contin- position. ued to decrease to 21% depression level by 10 min Second, it is also possible that the beneficial effects after the block and maintained at this depressed level of the lithotomy position on systemic blood pressure for the entire study period. after spinal anesthesia may be related to increased afterload due to the elevation of the lower extremities. Again, this effect is greater in the lithotomy position Discussion than in the head-down tilt position, because the high- This study has shown that the lithotomy position after est point above the heart is higher in the lithotomy spinal anesthesia is effective in increasing blood pres- position than in the head-down tilt position, as men- sure. We previously reported that the effect of head- tioned before. Compression of the lower extremity down tilt alone on the arterial blood pressure after arterial vasculature is not great in this study because spinal anesthesia was limited to severe hypotensive only the feet were tied to lift the legs. cases, and that the effect was small and was not The third factor involves the cephalad spread of necessarily consistent (3). Others have reported that in analgesic levels. The analgesic level of spinal block is 98 REGIONAL ANESTHESIA AND PAIN MANAGEMENT MIYABE ET AL. ANESTH ANALG LITHOTOMY, ARTERIAL BLOOD PRESSURE, AND SPINAL ANESTHESIA 1995;81:96-8 increased by the head-down tilt (3). Since sensory be interesting to know whether the blood pressure levels of spinal anesthesia to T-3 are associated with difference was maintained or if spinal anesthesia con- total sympathetic denervation (l), increase of analge- tinued to advance cephalad after 20 min. However, sic levels up to T-3 may cause further decrease of the since there were several factors, such as the difference blood pressure. We have shown in this study that the of operation between two groups and the effect of analgesic level is not affected by placing patients in the sedation, it was difficult to assess the effect of the lithotomy position. Therefore, unlike head-down tilt, lithotomy position on blood pressure after starting the the lithotomy position does not cause further decrease operation. Analgesic level after 20 min of spinal block of blood pressure due to a higher level of block. This is almost at plateau if the position is not changed (7). may have also contributed to the greater effectiveness In this study, analgesic level was not measured during in lithotomy than head-down tilt position. operation, but after the end of operation (1-1.5 h) it Fourth, Moriyama (8) reported that when only the decreased one to two segments. head was tilted down while the body was kept hori- We conclude that the lithotomy position after spinal zontal, systemic blood pressure decreased. They at- anesthesia reduces the decrease in blood pressure and tributed this to carotid baroreflex, which also may be does not affect the analgesic level. Taken together with activated during the head-down tilt. Although this lasts only a short time (30 heart beats), it is completely our previous study (3), these results indicate that the opposite to the effect of head-down tilt which is be- lithotomy position is apparently superior to the head- lieved to increase blood pressure (1). In head-down down tilt position. tilt, carotid baroreflex probably occurs first, followed by increase of venous return. On the contrary, in the The authors gratefully thank Dr. T. J. K. Toung, Department of lithotomy position, head position is not changed and Anesthesiology and Critical Care Medicine, The Johns Hopkins baroreflex does not occur. This explains the consistent Medical Institutions, for helping us to revise this manuscript. result from lithotomy position. Gaffney et al. (9,10), reported that passive leg rais- ing (60”) or application of antishock trousers does not produce a significant or sustained autotransfusion ef- References fect in healthy volunteer. They attributed the reason to 1. Greene NM. Physiology of spinal anesthesia. 3rd ed. Baltimore: the fact that, in a healthy person, intravascular volume Williams & Wilkins, 1981. in the leg is relatively small (loo-250 mL) and is only 2. Greene NM. Preganglionic sympathetic blockade in man: a partly displaceable. Therefore, the effects of transloca- study of spinal anesthesia. The Torston Gordh Lecture, 1980. tion of blood volume to the central circulatory hemo- Acta Anaesthesiol Stand 1981;25:463-9. dynamics are negligible. However, after spinal block, 3. Miyabe M, Namiki A. The effect of head-down tilt on arterial blood pressure after spinal anesthesia. Anesth Analg 1993;76: with a greater quantity of venous blood pooling, there 549-52. is a greater displaceable intravascular volume. 4. Anzai Y, Nishikawa T. Heart rate responses to body tilt during Age in horizontal group was lower than in lithot- spinal anesthesia. Anesth Analg 1991;73:385-90. omy group in this study (Table 1). To evaluate the 5. Pricolo VE, Burchard K, Singh A. Trendelenburg versus PASG effect of age on outcome in this study, we separated ;yi!i;;.tion-hemodynamic response in man. J Trauma 1986;26: the horizontal group into two subgroups, a younger 6. Sibbald WJ, Paterson NAM, Holliday RL, Baskerville J. The group (age ~39 yr; mean, 33 +- 4 yr; y1 = 6) and an Trendelenburg position: hemodynamic effects in hypotensive older group (age 240 yr; mean, 43 ? 3 yr, n = B), and and normotensive patients. Crit Care Med 1979;7:218-24. compared the trends of change in systemic blood pres- 7. Sinclair CJ, Scott DB, Edstrom HH. Effect of the Trendelenberg sure after spinal anesthesia. As a result, mean values position on spinal anaesthesia with hyperbaric bupivacaine. Br J Anaesth 1982;54:497-500. in the older group were always slightly lower than in 8. Moriyama K. Cardiovascular response to cerebral circulatory the younger group, but there was no statistically sig- regulation during shifts in head position. Nichiidai-shi 1989;56: nificant difference between these two subgroups. So if 258-66. the age of the horizontal group was higher, the result 9. Gaffney FA, Thal ER, Traylor WF, et al. Hemodynamic effects of medical anti-shock trousers (MAST garment). J Trauma 1981;21: must be the same, or even more obvious, in compar- 931-7. ison to this study. 10. Gaffney FA, Bastian BC, Thal ER, et al. Passive leg raising does The effect of the lithotomy position was observed not produce a significant or sustained autotransfusion effect. only 20 min after spinal block in this study. It would J Trauma 1982;22:190-3.
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