Anesth Analg 2005;101:555-560
© 2005 International Anesthesia Research Society
doi: 10.1213/01.ANE.0000158465.17547.F1
REGIONAL ANESTHESIA
The Influence of Lumbosacral Cerebrospinal Fluid Volume on Extent and Duration of Hyperbaric Bupivacaine Spinal Anesthesia: A Comparison Between Seated and Lateral Decubitus Injection Positions
Hideyuki Higuchi, MD*,
Yushi Adachi, MD
, and
Tomiei Kazama, MD
*Department of Anesthesia, Self Defense Force Hanshin Hospital, Hyogo; and Department of Anesthesiology, National Defense Medical College, Saitama, Japan
Address correspondence and reprint requests to Hideyuki Higuchi, MD, Department of Anesthesiology, Tokyo Women’s Medical University, 8-1 Kawadacho, Shinjuku, Tokyo 162-8666, Japan. Address e-mail to higu-chi{at}ka2.so-net.ne.jp.
 |
Abstract
|
|---|
We designed the present study to examine the influence of lumbosacral cerebrospinal fluid (CSF) volume on the spread and duration of hyperbaric bupivacaine spinal anesthesia when the injection is made with the patient in the lateral position compared with that when the patient is in a seated position. Seventy-four patients undergoing peripheral orthopedic or urogenital surgery with spinal block were enrolled. Lumbosacral CSF volumes were calculated from axial magnetic resonance images. Patients were randomly assigned to 1 of 2 groups: the lateral (L) and seated (S) groups (n = 37 each). Spinal anesthesia (3 mL hyperbaric 0.5% bupivacaine) was administered using a 25-gauge pencil-type needle with the needle aperture directed cephalad and the patient in the lateral decubitus position with the non-operated side up (L group) or with the patient in a seated position (S group). Patients were turned supine immediately after spinal injection (L group) or after remaining seated for 2 min (S group). Statistical correlation coefficients (
) were assessed using Spearman’s rank correlation. There were negative correlations between CSF volume and peak sensory block level in both the L ( = –0.69, P < 0.0001) and S groups ( = –0.68, P < 0.0001). In the S group, but not in the L group, CSF volume significantly correlated with onset time of peak sensory block level ( = –0.48, P = 0.004), and time required for regression to L1–4 (P < 0.05–0.01). We conclude that CSF volume influences the spread of spinal anesthesia with hyperbaric bupivacaine regardless of patient position when the spinal injection is made. CSF volume influenced the duration of spinal sensory anesthesia when the injection was made with the patient in a seated position, but not in the lateral position.
|
Introduction
|
|---|
Lumbosacral cerebrospinal fluid (CSF) volume is a major factor governing the spread of local anesthetic solutions in the subarachnoid space, because CSF is the diluent for local anesthetic solutions (1–4). Carpenter et al. (3) demonstrated a strong correlation between lumbosacral CSF volume and the peak sensory block level of hyperbaric lidocaine (P = 0.02, r = –0.91) using magnetic resonance (MR) imaging in 10 volunteers. Their study (3), however, is open to criticism, in that the correlation depends on the inclusion of one particular volunteer with extreme values of lumbosacral CSF volume and peak sensory block level (5). When data from this subject are excluded, the correlation between lumbosacral CSF volume and peak sensory block level is no longer significant (P = 0.07, r = –0.67). Therefore, the first purpose of our investigation was to examine the influence of CSF volume on the extent and duration of hyperbaric bupivacaine spinal anesthesia with robust statistical power >95%.
The distribution of hyperbaric spinal anesthetic solution in CSF is also influenced by gravity (1,2). The spread of hyperbaric solutions injected with the patient in the lateral position is significantly different than when injected with the patient seated (1,6,7). We hypothesized that the influence of CSF volume on measures of hyperbaric spinal anesthesia when spinal injection is made with the patient in a seated position would differ from that when it is made with the patient in a lateral position. Thus, the second purpose of this investigation was to compare the influence of lumbosacral CSF volume on the spread and duration of hyperbaric bupivacaine spinal anesthesia injected with the patient in the lateral position with injection when the patient is in a seated position.
|
Methods
|
|---|
The present study was conducted at the Self Defense Force Hanshin Hospital in Hyogo, Japan and was approved by the Hospital Ethics Committee. Written informed consent was obtained from each patient before participation in the study. There were 74 patients, classified as ASA physical status I, undergoing orthopedic lower limb surgery with a thigh tourniquet or urogenital surgery, under hyperbaric bupivacaine spinal anesthesia. Apart from the usual contraindications to spinal anesthesia (coagulopathy, infection, or patient refusal), patients with obvious spinal postural abnormalities (kyphosis), or with neurologic disturbances, were excluded from the study.
Low thoracic and lumbosacral axial MR images for the measurement of CSF volume using an MR imaging system (Excel Art; Toshiba, Tokyo, Japan) operating at 1.5 T, and the posterior-anterior lumbar spine radiographs for the identification of the spinal level marking the intersection of a line joining the iliac crests, were obtained a few days before anesthesia. Axial MR images were obtained at 8-mm increments with a fast-spin echo sequence using a method similar to that previously described (4,8). One of the authors (YA), who was not involved in the assessment of the patients receiving hyperbaric bupivacaine spinal anesthesia, determined the dural sac and spinal cord areas for each image using the National Institutes of Health Image 1.63 program (public domain). The level of the disk between the 11th and 12th thoracic vertebrae was determined and the area of the sac minus the area of the cord was measured caudal from this site. CSF volume was defined as this area multiplied by 8 mm.
Patients were randomly assigned to 1 of 2 groups: the lateral position and seated groups (n = 37 each). Thirty minutes before transfer to the operating room (OR), all patients received an IM injection of atropine (0.5 mg). After placement of standard noninvasive monitoring devices, a midline lumbar puncture was performed using a 25-gauge pencil-type needle (Pencan®; B. Braun, Tokyo, Japan), at the L3–4 level, with the patient in the lateral decubitus position with the non-operated side up, or with the patient in a seated position. The L3–4 level interspace was identified by counting the spines of the vertebrae and palpating the iliac crest. After obtaining free CSF reflux, spinal injection of 3 mL (15 mg) hyperbaric bupivacaine in 7.3% glucose (4-mL vial Marcaine® 0.5%; AstraZeneca, Osaka, Japan) with the needle aperture directed cephalad was then performed over 15 s in both groups. In the lateral (L) group, the patient was immediately turned to the supine position and remained horizontal until the end of the operation, whereas in the seated (S) group, the patient remained seated for 2 min after the injection before being placed in the supine position.
The extent of the sensory block was assessed by pinprick (23-gauge) on the skin on the midline from top to bottom of the body up to T12 and on the nondependent side thereafter. For practical reasons, motor block was evaluated only on the non-operated side by the previously described modified Bromage scale (0 = able to move hip, knee, ankle, and toes; 1 = unable to move hip, able to move knee, ankle, and toes; 2 = unable to move hip and knee, able to move ankle and toes; 3 = unable to move hip, knee, and ankle, able to move toes; 4 = unable to move hip, knee, ankle, and toes) (4). Hemodynamic data (mean arterial blood pressure) were also recorded. Data sampling was performed every 5 min for the first 45 min after spinal injection and then every 15 min until the end of the observation period, which was defined as regression of the sensory block level to L5. These data were recorded by the nurses of the OR and the orthopedic ward in charge of the patient, who were unaware of the purpose of the study. Acetated Ringer’s solution was administered 5 mL/kg 1 h before spinal anesthesia, and 1 mL · kg–1 · h–1 during and after anesthesia. Ephedrine (5 mg) was administered IV when mean arterial blood pressure decreased by >30% of the baseline value. IV atropine (0.5 mg) was used to treat a heart rate of <45 bpm. The relation between the peak sensory block level and lowest mean arterial blood pressure for 60 min after spinal injection was calculated.
The patient sample size of the current study was determined by power analysis (two-tailed 
= 0.05, ß = 0.20) to reveal a significant correlation coefficient. Power analysis indicated that 37 patients were required to obtain a significant correlation coefficient, assuming that the two variables were continuous data and the correlation coefficient between the CSF volume and the time to two-segment regression from peak sensory block level in the S group was 0.45, based on our preliminary study. Continuous data were expressed as mean ± sd, and discrete data were expressed as medians and ranges. Data were analyzed using Mann-Whitney U-test or Fisher’s exact probability test, where appropriate. Statistical correlation coefficients () were assessed with Spearman’s rank correlation for the CSF volume, peak sensory block level to pinprick, time until the development of peak sensory level and maximal motor block, degree of maximal motor block, time for the peak sensory level to regress across two segments, time for pinprick analgesia to regress to the L1–5 dermatomes, time until complete motor recovery, lowest mean arterial blood pressure, and dose of ephedrine used. A P value < 0.05 was considered statistically significant.
In addition, multiple linear regression analysis was used to examine the relative importance of patient variables to the aforementioned measures of spinal anesthesia. Age, height, weight, body mass index, and CSF volume were considered independent variables. Multicolinearity among the variables can hinder the interpretation of results. Therefore, forward and backward stepwise selections were used to identify independently associated variables. For adding and deleting variables, the F ratio criterion was 4.0, which is the squared value obtained from a t-test for the hypothesis that the coefficient of the variable in question equals zero (4,8).
|
Results
|
|---|
Demographic characteristics, CSF volume, and anesthetic and hemodynamic data of both groups are presented in Table 1. There were no significant differences between the two groups in demographic characteristics and CSF volume. There were significant differences in peak sensory block level and time until the development of peak sensory block level and maximal motor block, whereas there were no differences in the recovery profiles of sensory and motor block between the two groups (Table 1). There were significant differences between the two groups in the lowest mean arterial blood pressure, number of patients requiring ephedrine, and ephedrine dose used.
Correlations between CSF volume and the measures of spinal anesthesia, and among the measures of spinal anesthesia both in the L and S groups are presented in Table 2. There were negative correlations between CSF volume and peak sensory block level in both the L ( = –0.69, P < 0.0001) and S groups ( = –0.68, P < 0.0001; Table 2, Fig. 1). Lumbosacral CSF volume did not correlate with the time until the development of peak sensory block level in the L group, whereas there was a negative correlation between CSF volume and onset time of peak sensory block level in the S group ( = –0.48, P = 0.004; Table 2, Fig. 2). Similarly, CSF volume significantly correlated with the time for the sensory level to regress from the peak block level across two segments ( = 0.33, P = 0.045), and negatively correlated with time required for regression to L1 ( = –0.39, P = 0.019), L2 ( = –0.39, P = 0.021), L3 ( = –0.44, P = 0.008), and L4 ( = –0.38, P = 0.023) in the S group, whereas there were no significant correlations among these variables in the L group (Table 2). However, CSF volume significantly correlated with the degree of motor block ( = –0.55, P = 0.001), lowest mean arterial blood pressure ( = 0.50, P = 0.003), and ephedrine dose ( = –0.38, P = 0.025) in the L group, whereas there were no correlations among these variables in the S group (Table 2).
View this table:
[in this window]
[in a new window]
|
Table 2. Correlations Between Cerebrospinal Fluid Volume and Measures of Spinal Anesthesia in the Lateral and Seated Groups
|
|
The significant multiple linear regression analyses are shown in Table 3. There were 5 significant correlations among independent variables in the L group, whereas there were 11 significant correlations among independent variables in the S group (P < 0.05). Multiple regression analysis revealed that age and CSF volume significantly contributed to the peak sensory block level (an increase in either age or CSF volume was associated with a lower peak sensory block level), and that R2 values > 0.5 were predictive in both the L and S groups (Table 3). Besides the peak level, CSF volume was included as a significant predictive variable in almost all significant correlations, but the R2 values were far <0.5, indicating that it is poorly predictive.
|
Discussion
|
|---|
The principal finding of the present study is that there was a significant relationship between CSF volume and peak sensory block level in the L group with a large sample size, which confirms the study by Carpenter et al. (3), who demonstrated a significant relation between CSF volume and peak sensory block level after the administration of hyperbaric lidocaine. CSF volume also correlated with peak sensory block level in the S group. There was, however, no difference in the correlation coefficient between the 2 groups, which was contrary to our hypothesis ( = –0.68 versus –0.69). However, consistent with our hypothesis, CSF volume correlated with the time until the development of peak sensory level to pinprick, the time for the peak sensory level to regress across two segments, and time for pinprick analgesia to regress to the L1–4 in the S group. There was no significant correlation among these variables in the L group.
In the present study, the patient position during the subarachnoid injection significantly affected the spread of hyperbaric bupivacaine spinal anesthesia. Although the median peak sensory block level in both the L and S groups was T5, the peak sensory block level in the L group was significantly higher than that in the S group (P < 0.05, Mann-Whitney U-test). This is consistent with the findings reported by Wildsmith et al. (7), who demonstrated that 15 mg of tetracaine injected with patients in the lateral position and then immediately turned to the supine position resulted in a significantly higher level of anesthesia than when it was injected with patients in a seated position, the position being maintained for 2 minutes before patients were placed in the supine position (T4 versus T8). In addition, the time to the development of the peak sensory block level to pinprick and maximal motor block were significantly shorter in the L group compared with the S group. The hemodynamic effects were also greater, resulting in larger ephedrine doses required for the L group than for the S group. The decrease in hemodynamic response in the S group may result from the slower spread of spinal anesthesia, because the difference in the peak level between the two groups was only one segment. The degree of arterial hypotension after subarachnoid injection of local anesthetics correlates with peak sensory block level (4,9). In the current study, there were significant correlations between the maximal decrease in mean arterial blood pressure and peak sensory block level in both the L and S groups (L: = –0.64, P < 0.001; S: = –0.47, P < 0.01).
When a subarachnoid injection is made at the apex of the lumbar curvature with the patient in the lateral position and the patient is then turned to the supine position, hyperbaric solutions immediately spread in both the cephalad and caudad directions because of gravity (1,6). However, when hyperbaric solutions are injected with the patient in a seated position, hyperbaric bupivacaine pools in the sacral region while the position is maintained upright for 2 minutes. After the patient is turned to the supine position, the pooled hyperbaric solutions spill over from the apex of the lumbar curvature and spread downward in the cephalad direction because of gravity (1,6). We hypothesized that the influence of CSF volume on the measures of spinal anesthesia would differ between the lateral and seated positions because hyperbaric bupivacaine might be more uniformly diluted by lumbosacral CSF volume when injected with the patient in a seated position than when in the lateral position. Indeed, only in the S group were there significant correlations between CSF volume and the recovery profile. Contrary to our hypothesis, however, there was no difference in the correlation coefficient between peak sensory block level and CSF volume between the two groups. One possible explanation for the lack of a significant difference in the correlation coefficient might be related to the fact that a large dose of bupivacaine, 15 mg, was injected in the both groups, resulting in only a one-segment difference in the peak sensory block level between the two groups. Whether the area of anesthesia is restricted to only sacral and lower lumbar roots depends on the dose of anesthetic solution injected with the patient in a seated position (1).
CSF volume variability partly accounts for the unpredictable extent of spinal anesthesia (3,4). Although the unpredictability of plain bupivacaine is reportedly greater than that of hyperbaric bupivacaine spinal anesthesia (10), the correlation coefficient () between CSF volume and peak sensory block level of plain bupivacaine in our previous study (4) was similar to that in the L group in the present study (–0.65 versus –0.69). In plain bupivacaine spinal anesthesia, CSF density is another important factor influencing the spread of spinal anesthesia (4,9). The influence of such factors on the extent of spinal anesthesia might be related to the unpredictability of plain bupivacaine. In contrast, it is unlikely that CSF density influences subarachnoid distribution of hyperbaric bupivacaine because of the excess baricity above 1.0015 (1).
There are several limitations in this study. First, the possible influence of the injection site must be considered (9,11). The effects of varying sites of injection have not been studied extensively with hyperbaric bupivacaine. Veering et al. (12) reported that the highest analgesia levels when the injection was at the L3–4 interspace did not differ from that at the L4–5 interspace. Second, the correlation coefficients and R2 values in measures of the recovery profile, such as time to regression to L3, were significantly less than those in the peak sensory block level. These low values are consistent with those obtained in previous studies (1,4). The weak or lack of a correlation between CSF volume and the regression to L1–5 might be related to the high degree of interindividual variability at these segments (4,13). Finally, our findings are not helpful for guiding clinical practice, although they provide valuable insight into the mechanism of hyperbaric bupivacaine spinal anesthesia. Although the R2 of the peak sensory block level exceeded 0.5, indicating that it is predictive, our results cannot be expected to improve the spread of hyperbaric spinal anesthesia, because MR images are not usually obtained before anesthesia.
In conclusion, the present study indicates that CSF volume is the main factor that influences the spread of hyperbaric bupivacaine spinal anesthesia and that patient position during the spinal injection does not alter this influence. In contrast, CSF volume influences the duration of spinal anesthesia when the injection is made with the patient in a seated position, but not in a lateral position.
|
Footnotes
|
|---|
This study was supported by funding from institutional and department resources only.
Accepted for publication January 21, 2005.
|
References
|
|---|
- Greene NM. Distribution of local anesthetic solutions within the subarachnoid space. Anesth Analg 1985;64:715–30.[Free Full Text]
- Liu SS, McDonald SB. Current issues in spinal anesthesia. Anesthesiology 2001;94:888–906.[ISI][Medline]
- Carpenter RL, Hogan QH, Liu SS, et al. Lumbosacral cerebrospinal fluid volume is the primary determinant of sensory block extent and duration during spinal anesthesia. Anesthesiology 1998;89:24–9.[ISI][Medline]
- Higuchi H, Hirata J, Adachi Y, Kazama T. Influence of lumbosacral cerebrospinal fluid density, velocity, and volume on extent and duration of plain bupivacaine spinal anesthesia. Anesthesiology 2004;100:106–14.[ISI][Medline]
- Marsch SC, Staender S. Does the variability in the volume of lumbosacral cerebrospinal fluid affect sensory block extent of spinal anesthesia? Anesthesiology 1999;90:923–4.[ISI][Medline]
- Kitahara T, Kuri S, Yoshida J. Spread of drugs used for spinal anesthesia. Anesthesiology 1956;17:205–8.[ISI][Medline]
- Wildsmith JA, McClure JH, Brown DT, Scott DB. Effects of posture on the spread of isobaric and hyperbaric amethocaine. Br J Anaesth 1981;53:273–8.[Abstract/Free Full Text]
- Higuchi H, Adachi Y, Kazama T. Factors affecting the spread and duration of epidural anesthesia with ropivacaine. Anesthesiology 2004;101:451–60.[ISI][Medline]
- Schiffer E, Van Gessel E, Fournier R, et al. Cerebrospinal fluid density influences extent of plain bupivacaine spinal anesthesia. Anesthesiology 2002;96:1325–30.[ISI][Medline]
- Logan MR, McClure JH, Wildsmith JA. Plain bupivacaine: an unpredictable spinal anaesthetic agent. Br J Anaesth 1986;58:292–6.[Abstract/Free Full Text]
- Kim JT, Bahk JH, Sung J. Influence of age and sex on the position of the conus medullaris and Tuffier’s line in adults. Anesthesiology 2003;99:1359–63.[ISI][Medline]
- Veering BT, Ter Riet PM, Burm AG, et al. Spinal anaesthesia with 0.5% hyperbaric bupivacaine in elderly patients: effect of site of injection on spread of analgesia. Br J Anaesth 1996;77:343–6.[Abstract/Free Full Text]
- Hogan Q. Size of human lower thoracic and lumbosacral nerve roots. Anesthesiology 1996;85:37–42.[ISI][Medline]
This article has been cited by other articles:
|
|
|
|
 
C. Arzola, M. Balki, and J. C.A. Carvalho
The antero-posterior diameter of the lumbar dural sac does not predict sensory levels of spinal anesthesia for Cesarean delivery: [Le diametre anteroposterieur du sac dural lombaire ne predit pas l'etendue des niveaux sensitifs de la rachianesthesie pour la cesarienne]
Can J Anesth,
August 1, 2007;
54(8):
620 - 625.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. T. Sullivan, S. Grouper, M. T. Walker, T. B. Parrish, R. J. McCarthy, and C. A. Wong
Lumbosacral Cerebrospinal Fluid Volume in Humans Using Three-Dimensional Magnetic Resonance Imaging
Anesth. Analg.,
November 1, 2006;
103(5):
1306 - 1310.
[Abstract]
[Full Text]
[PDF]
|
|
|
Top
Abstract
Introduction
