Objective: To compare the effect of induction position on block characteristics (sensory and motor nerves) and haemodynamic stability in elderly patients with isobaric bupivacaine. Patient comfort was also looked at.Methods: The randomized single blinded study was conducted at the Aga Khan University Hospital, Karachi, from September 2007 to August 2008. A total of 70 patients aged \u3e60 years of both genders were included. Spinal anaesthesia was performed either in sitting or lateral position according to random allocation. Assessments of sensory, motor block and heart rate, systolic and diastolic blood pressure were recorded for 20 minutes. SPSS 16 was used for statistical analysis.Results: There was no significant difference for haemodynamic variables heart rate, systolic and diastolic blood pressure. The onset of anaesthesia was faster in the sitting group (4.5 minutes vs 5.4 minutes). The motor block characteristics were similar in both the groups. The majority of patients who reported \u27very comfortable\u27 for induction position belonged to the lateral group.CONCLUSION: Both sitting and lateral positions have similar effects on sensory and motor blockade and haemodynamic stability. However, patients generally found lateral position very comfortable

Afshan, Gauhar

Shahzad, Khurrum

English

eCommons@AKU

eCommons@AKUDepartment of Anaesthesia Medical College, PakistanJanuary 2013Induction position for spinal anaesthesia: sittingversus lateral positionKhurrum ShahzadGauhar AfshanAga Khan University, gauhar.afshan@aku.eduFollow this and additional works at: https://ecommons.aku.edu/pakistan_fhs_mc_anaesthPart of the Anesthesia and Analgesia Commons, and the Anesthesiology CommonsRecommended CitationShahzad, K., Afshan, G. (2013). Induction position for spinal anaesthesia: sitting versus lateral position. Journal of Pakistan MedicalAssociation, 63(1), 43409.Available at: https://ecommons.aku.edu/pakistan_fhs_mc_anaesth/256Vol. 63, No.1, January 201311IntroductionThe number of elderly patients presenting for surgery hasincreased exponentially in recent years and spinalanaesthesia appears to be more beneficial in thesepatients for lower limb and urological surgeries.1,2 Spinalanaesthesia can be initiated with the patient in either thesitting or the lateral position, and each position has itsadvantages and disadvantages.3In elderly patients, spinal anaesthesia may be technicallydifficult due to age-related degenerative anatomicalchanges. The sitting position appears to be optimal forthe placement of spinal anaesthesia as identification oflandmark, particularly midline, is much easier. However,maintaining the sitting position is often difficult for pre-medicated patients. On the other hand, lateral position isgenerally considered easy to maintain for the elderly pre-medicated patients. However, the identification ofanatomical landmark is difficult. The medicalsympathectomy following spinal anaesthesia withenhanced gravity-induced peripheral blood pooling,especially in the sitting position often results in significanthypotension.1 Compared to the sitting position, thelateral position may cause less hypotension.2In spite of increasing use of spinal anaesthesia, theinduction position (position for initiating spinalanaesthesia) has not been standardised. In currentpractice, the patient's position during the initiation ofspinal anaesthesia is at the discretion of the anaesthetist.In elderly patients, influence of the positions onhaemodynamic stability and block character (sensory andmotor nerve) has not been studied recently. This studywas designed to compare haemodynamic effects andblock characteristics associated with sitting and lateralpositions for initiating spinal anaesthesia in the elderly.Patient satisfaction was also looked at. Patients and MethodsThe study was conducted after approval from theinstitutional ethical review committee at the Aga KhanUniversity Hospital, Karachi, from September 2007 toAugust 2008. It included 70 American Society ofAnesthesiologists (ASA) I, II and III patients of bothgenders of age more than 60 years undergoing spinalanaesthesia for lower abdomen, pelvic and lower limbsurgery. Consent refusal, patient with weight more than85kg, height more than 175cm or less than 150cm andthose with the contraindication of regional anaesthesiawere excluded from the study. Informed written consentwas obtained from all patients.For sample size determination, the ranges of time ofhighest sensory block (T10) in each group wereconsidered as 5.5 and 6, and standard deviations(Range/4) came out to be 1.4 and 1.5 respectively.According to calculations, 35 patients in each groupachieved 80% power to detect a mean difference of 1 withORIGINAL ARTICLEInduction position for spinal anaesthesia: Sitting versus lateral positionKhurrum Shahzad, Gauhar AfshanAbstractObjective: To compare the effect of induction position on block characteristics (sensory and motor nerves) andhaemodynamic stability in elderly patients with isobaric bupivacaine. Patient comfort was also looked at.Methods: The randomized single blinded study was conducted at the Aga Khan University Hospital, Karachi, fromSeptember 2007 to August 2008. A total of 70 patients aged >60 years of both genders were included. Spinalanaesthesia was performed either in sitting or lateral position according to random allocation. Assessments ofsensory, motor block and heart rate, systolic and diastolic blood pressure were recorded for 20 minutes. SPSS 16 wasused for statistical analysis.Results: There was no significant difference for haemodynamic variables heart rate, systolic and diastolic bloodpressure. The onset of anaesthesia was faster in the sitting group (4.5 minutes vs 5.4 minutes). The motor blockcharacteristics were similar in both the groups. The majority of patients who reported 'very comfortable' forinduction position belonged to the lateral group.Conclusion: Both sitting and lateral positions have similar effects on sensory and motor blockade andhaemodynamic stability. However, patients generally found lateral position very comfortable.Keywords: Spinal anaesthesia, Lateral decubitus position, Induction position, Isobaric bupivacaine. (JPMA 63: 11; 2013)Department of Anaesthesia, Aga Khan University Hospital, Karachi, Pakistan.Correspondence: Gauhar Afshan. Email: gauhar.afshan@aku.edu5% level of significance.For this randomised single blinded study, patients wererandomly allocated to one of the two groups by pickingsealed envelopes. Patient and primary investigator werenot blinded, and data was collected by a trainedindependent observer to make the study single blinded.Patients were routinely pre-medicated with oralmidazolam 7.5mg and preloaded with 7-8ml of crystalloidsolution. Baseline heart rate and blood pressure (BP) wererecorded after which the data collector was asked to leavethe operating room. Spinal anaesthesia was performedwith the patient in sitting or lateral position at L3-L4 or L4-L5 level via midline approach, using a 25-gauge pencil-point spinal needle with introducer. In the sitting group,patients were sitting with feet resting on a stool and backfacing towards the anaesthetist, while in the lateral group,they were lying on the operating table with knee and hipjoint in flexion position during the initiation of spinalanaesthesia.The Bupivacaine 12.5mg of 0.5% isobaric was injectedwith bevel of needle facing upward at a speed of0.5ml/sec. Patients were placed in the supine positionimmediately after withdrawing the spinal needle and thedata collector was called again.Every two minutes after the injection of spinalanaesthesia until 20 minutes, assessments were made forheight of sensory and density of motor nerve block andcardiovascular parameters, including heart rate, systolicand diastolic blood pressures. Sensory level assessmentwas done with ice and motor block assessment with 0-3point scale.4 [0 (none) full flexion of knees and feet; 1(partial) just able to move knees and feet; 2 (almostcomplete) able to move feet only; 3 (complete) unable tomove feet or knees.]The cardiovascular side effect, e.g. decrease in meanarterial blood pressure >25% of the baseline levels, wastreated by incremental doses of intravenous ephedrine5mg or phenylephrine 100µg, while decrease in the heartrate below 45 beats per minute was treated by 1mgatropine. The primary outcome was the sensory block level duringthe first 20 minutes after the spinal anaesthesia. Otheroutcome included motor block score, bradycardia andhypotension, and vasopressor requirements. After spinalanaesthesia and prior to the start of surgery, patients wereasked about their satisfaction for overall comfort level forposition (sitting or lateral) during spinal anaesthesia interms of three options: not comfortable, comfortable, andvery comfortable.Data was analysed using SPSS 16. Mean ± standarddeviation was computed for age, weight, height. Time toachieve density of motor block and height of sensoryblock was compared using independent samples t- test.Chi square test was applied to compare patient comfortand cardiovascular side effects. Repeated measuresAnalysis of Variance (ANOVA) was used to compare effectslike heart rate, systolic and diastolic blood pressures of thetwo groups. P value of 0.05 or less was consideredstatistically significant.ResultsDemographic characteristics of patients in both groupsJ Pak Med Assoc12Table-1: Demographics.Variable Group Mean Standard Deviation p-valueAge of the patient (years) Sitting 66.94 4.99 0.012*Lateral 70.74 7.18Weight of patient (kg) Sitting 69.02 9.63 0.659Lateral 67.97 10.33Height of patient (cm) Sitting 164.80 7.82 0.453Lateral 166.14 7.04Body Mass Index Sitting 25.43 3.29 0.236Lateral 24.54 2.94Figure: Comparison of comfort level with positioning between the two groups.Vol. 63, No.1, January 2013Induction position for spinal anesthesia: Sitting versus lateral position 13were matched. Only mean age was statistically significant(p <0.012) (Table-1). Other variables including ASA level,type of surgery and level of needle insertion were alsomatched. The time for onset of sensory block in the sitting groupTable-2: Comparison of sensory block height achieved.Height of Group p-valuesensory block A (Sitting) B (Lateral)T8 13 (37.1%) 22 (62.9%)T7 13 (37.1%) 6 (17.1%)T6 3 (8.6%) 5 (14.3%) 0.064T5 3 (8.6%) 2 (5.7%)T4 3 (8.6%) 0 (0.0%)Total 35 35Graph-1: Comparison of mean motor block in the right lower limb between the twogroups at different time intervals.Graph-2: Comparison of mean motor block in the left lower limb between the twogroups at different time intervals.Graph-3: Comparison of mean heart rate between the two groups at different timeintervals.Repeated measure ANOVA applied to compare mean heartrate between groups (p=0.52)Graph-4: Comparison of mean systolic blood pressure between the two groups atdifferent time intervals.Repeated measure ANOVA applied to compare mean heartrate between groups (p=0.36).was 4.5 minutes compared with 5.4 minutes in the lateralgroup (p <0.006). The mean time to achieve T10 level was8.17±1.5 minutes in the sitting group and 7.71±1.3minutes in the lateral group (p <0.175). In the sitting group, 3 (8.6%) patients had highest sensoryblock up to T4 level, while in the lateral group, 2 (5.7%)achieved sensory block up to T5 level (Table-2). There wasno difference between the groups for maximum densityof motor block (3/3) and mean time to achieve this (Graph1 and 2).No significant difference was observed between the twogroups for heart rate at any stage from the baseline until20 minutes after the onset of spinal anaesthesia (Graph 3).There was no statistically significant difference in themean systolic blood pressure between the two groups(Graph 4). The groups were also well matched for diastolicblood pressure except at the baseline and the onset ofspinal anaesthesia (Graph 5).In the sitting group, 6 (17%) patients and in the lateral,four (11%) had hypotensive episode requiringvasopressors at one or more times (P <0.734). None of thepatients in the lateral group had bradycardia, while 3(8.6%) in the sitting group had one episode of bradycardiawhich required treatment with atropine. This differencewas statistically insignificant. As regards the induction positions for the initiation ofspinal anaesthesia, more patients in the lateral groupreported to be in the 'comfortable category' than in thesitting group (Figure).DiscussionThere is some debate whether the induction position,sitting or lateral, during spinal anaesthesia may affect thespread of isobaric local anaesthetic drugs and eventuallyinfluence the characteristics of the nerve blockade(sympathetic, sensory and motor).5,6The role of induction position during spinal anaesthesiausing hyperbaric bupivacaine is proven to some extent.However, its effects with isobaric bupivacaine in elderlypatients have not been sufficiently studied. There is adefinite paucity of literature with comparative study ofspinal anaesthesia in this age group, addressing the issueof patient's position for the initiation of spinal anaesthesiawith isobaric bupivacaine.In our study, demographic characteristics of both thegroups were comparable except that the mean age in thelateral group was more than the sitting group patients.However, it did not seem to have any impact on theoverall outcome considering the other well-matchedparametres including body mass index (BMI) and ASAstatus.In our study, the onset of spinal anaesthesia was faster inthe sitting than in the lateral position (4.5 vs 5.4 minutes).Although this difference was statistically significant, butapparently would not be of much significance clinically astime to achieve T10 level, which matters the most, wascomparable (8.17 vs. 7.71 minutes). The finding of ourstudy was contrary to previous literature where meansensory block of T10 was achieved at 10 minutes in boththe groups.1 This increased time to achieve the desiredlevel may be explained by lesser dose of local anaestheticdrugs used in the study compared to our dosages. The sympathetic blockade usually results in hypotensionwhether the patient is in the sitting or the lateral position.The vasovagal episode might occur with a greatfrequency or severity in the sitting position and additionalgravity-dependent peripheral pooling may result inorthostatic hypotension in the sitting position.7,8 In ourstudy, 3 patients in the sitting position had sensory blocklevel up to T4 (more than the desired level of T10), whilenone of the patients had T4 in the lateral position. Thisfinding is consistent with the previous study whichreported higher spread of isobaric bupivacaine up to T4level in the sitting position compared with the lateralposition.9 In our study, motor nerve blockade did notseem to change with position as reported earlier.10,11In terms of cardiovascular effects, our study showedsimilar trends in both the groups. However, significantdifferences in the mean systolic/diastolic blood pressureJ Pak Med Assoc14 K. Shahzad, G. AfshanGraph-5: Comparison of mean diastolic blood pressure between the two groups atdifferent time intervals.Vol. 63, No.1, January 2013Induction position for spinal anesthesia: Sitting versus lateral position 15between the two groups were found at the baseline level.This increased baseline BP could be due to individual highlevel of anxiety upon arrival in the operating room as thegroups were very well matched at other study timings.Both the study groups were also very well matched forepisodes of bradycardia/hypotension requiringtreatment. These findings were almost similar to what hasbeen reported previously.2In this study, more patients in the lateral position reported'very comfortable' compared to the sitting group. This isdifferent from the previously reported finding where thepatient comfort level was almost similar between the twogroups.1 In our study, all patients received pre-medicationwith midazolam. Thus, the patients might have felt morecomfortable in the lateral position than sitting up in bed.The earlier study did not comment about the effect of pre-medication with the position.Our study had its strengths and limitations. It was the firststudy addressing the position effect of elderly patientsduring spinal anaesthesia with isobaric bupivacaine inPakistani population, and covered several bases likesensory and motor blockade as well as haemodynamicstability. However, due to the small sample size, some ofthe findings remain questionable. We also did not lookinto the anaesthetist's preference for the inductionposition. Although it is perceived that spinal anaesthesiais easier to perform in the sitting position, but there is nopublished evidence to indicate this. ConclusionBoth sitting and lateral positions have similar effects onsensory and motor blockade and haemodynamic stability.However, patients found the lateral position mostcomfortable.References1. Fredman B, Zohar E, Rislick U, Sheffer O, Jedeikin R. Intrathecalanaesthesia for the elderly patient: the influence of the inductionposition on peri operative haemodynamic stability and patientcomfort. Anaesth Intensive Care 2001; 29: 377-82.2. Kelly JD, Mccoy D, Rosenbaum SH, Brull SJ. Haemodynamicchanges induced by hyperbaric bupivacaine during lateraldecubitus or supine spinal anaesthesia. Eur J Anaesthesiol 2005;22: 717-22.3. David J. Birnbach,Ingrid M. Browne.Anesthesia for Obstetrics. In:Miller RD, ed. Anesthesia. 7th ed. Churchill Livingstone, An Imprintof Elsevier, 2009; pp 2203-40.4. Gori F, Corradetti F, Cerotto V, Peduto VA. Influence of Positioningon Plain Levobupivacaine Spinal Anesthesia in Cesarean Section.Anesthesiol Res Pract 2010; 2010: 212696.5. Zohar E, Nog Y, Laboritck I, Fredman B. Intrathecal anesthesia forelderly patient undergoing short transurethral procedure: a dosefinding study. AnesthAnalg 2007; 104: 552-4.6. Russel IF. Routine use of sitting position for spinal anaesthesiashould be abandoned in obstetric practice. Int J ObstetAnesthesia 2008; 17: 343-7.7. Mastoshi N, Usukaura A, Kidani Y, Tsubokawa T, Yamamoto K.Which is a better position for insertion of a high thoracic epiduralcatheter: sittong or lateral decubitus? J Cardiothoracic VascAnesth 2006; 20: 656-8.8. Salvi L, Sisillo E, Rondello N. Success rate, decubitus position andvagal reflex during high thoracic epidural for coronary arterysurgery. J Cardiothoracic Vasc Anesth 2007; 21: 919-20.9. Stienstra R, van Poorten JF. The temperature of bupivacaine 0.5%affects the sensory level of spinal anesthesia. Anesth Analg 1988;67: 272-6.10. Kalso E, Tuominen M, Rosenberg PH. Effect of posture and someCSF characteristics on spinal anaesthesia with isobaric 0.5%bupivacaine. Br J Anaesth 1982; 54: 1179-84.11. Kuusniemi KS, Pihlajamaki KK, Pitkanen MT, Helenius HY, KirvelaOA. The use of bupivacaine and fentanyl for spinal anesthesia forurologic surgery. 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Induction position for spinal anaesthesia: sitting versus lateral position

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Induction position for spinal anaesthesia: sitting versus lateral position

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