1. Hypobaric Spinal Anesthesia Consideration
Presented By R3 顏郁軒 /11/01

2. Question Marcain choice : heavy , plain , or hypobaric
Volume and Concentration VS
Sensory block level & Duration
Hemodynamic change
Lateral decubitus VS supine

3. Miller
the mass of drug (mg dose) injected is more important in determining the eventual block height than the volume of isobaric drug administered
the mean value of CSF specific gravity :1.0069

4. Cerebrospinal Fluid Density Influences Extent of Plain Bupivacaine Spinal Anesthesia
Anesthesiology 2002; 96:1325–30
Hyperbaric solution : position dependent plain solution : not or less position dependent
Lateral decubitus  collect CSF 2 ml & 3 ml(15mg) plain Marcaine was injected  supine

5. Cerebrospinal Fluid Density Influences Extent of Plain Bupivacaine Spinal Anesthesia

6. Cerebrospinal Fluid Density Influences Extent of Plain Bupivacaine Spinal Anesthesia

7. Cerebrospinal Fluid Density Influences Extent of Plain Bupivacaine Spinal Anesthesia
The higher the CSF density, the higher the maximal level of block observed for plain bupivacaine solutions.
CSF density is significantly different between some subgroup populations (higher in men than in women, higher in postmenopausal than premenopausal women, higher in nonpregnant than in pregnant women)

9. I (n=30): 1.2 ml 0.5% plain Marcaine II (n=30): 3.4 ml 0.18 % Marcaine
Low-dose bupivacaine: a comparison of hypobaric and near isobaric solutions for arthroscopic surgery of the knee
Anaesthesia, 1999, 54, pages 540–545
I (n=30): 1.2 ml 0.5% plain Marcaine II (n=30): 3.4 ml 0.18 % Marcaine
Lateral decubitus for 20 mins post spinal anesthesia and slight head –down(10o)

10. Low-dose bupivacaine: a comparison of hypobaric and near isobaric solutions for arthroscopic surgery of the knee

11. Low-dose bupivacaine: a comparison of hypobaric and near isobaric solutions for arthroscopic surgery of the knee
the hypobaric solution spread one dermatome higher than the plain solution
The motor block between operated and nonoperated sides was significantly
different at all testing times irrespective of the solution used

12. Low-dose bupivacaine: a comparison of hypobaric and near isobaric solutions for arthroscopic surgery of the knee
Our results indicate that a mainly unilateral motor and sensory block can also be obtained with the less hypobaric solution when the patients remain in the lateral position 20 min after the injection of the local anaesthetic.
This finding suggests that total dosage is more important than the volume used even when using low doses of local anaesthetic

13. Low-dose bupivacaine: a comparison of hypobaric and near isobaric solutions for arthroscopic surgery of the knee
Hemodynamic status Group I: 2 p’t with hypotension Group II : 1 p’t with hypotension No bradycardia was seen

14. Isobaric Versus Hypobaric Spinal Bupivacaine for Total Hip Arthroplasty in the Lateral Position
Anesth Analg 2003;97:589 –94
Group I (n=20) : 3.5 ml plain Marcaine (17.5mg) + 1.5ml normal saline
Group II (n=20) : 3.5 ml plain Marcaine (17.5mg) + 1.5ml distilled water

15. Isobaric Versus Hypobaric Spinal Bupivacaine for Total Hip Arthroplasty in the Lateral Position
Patients remained in the lateral position until the end of surgery
Evolution of upper sensory block level & motor function on nondependent (operative) and dependent sides
Mean arterial blood pressure (MAP) and heart rate (HR) were recorded

16. Isobaric Versus Hypobaric Spinal Bupivacaine for Total Hip Arthroplasty in the Lateral Position

17. Isobaric Versus Hypobaric Spinal Bupivacaine for Total Hip Arthroplasty in the Lateral Position

18. Isobaric Versus Hypobaric Spinal Bupivacaine for Total Hip Arthroplasty in the Lateral Position
hypobaric bupivacaine showed a significantly delayed sensory regression to L2 on the nondependent side of 45 minutes

19. Group I (n=25) : 7.5 mg (1.5 ml , 0.5% heavy Marcaine )
A Low-Dose Bupivacaine: A Comparison of Hyperbaric and Hypobaric Solutions for Unilateral Spinal Anesthesia
Regional Anesthesia and Pain Medicine, Vol 29, No 1 (January–February), 2004: pp 17–22
Group I (n=25) : 7.5 mg (1.5 ml , 0.5% heavy Marcaine )
Group II (n=25) : 7.5 mg (4.2 ml , 0.18% plain Marcaine)
Lateral position for 15 mins

20. A Low-Dose Bupivacaine: A Comparison of Hyperbaric and Hypobaric Solutions for Unilateral Spinal Anesthesia

21. A Low-Dose Bupivacaine: A Comparison of Hyperbaric and Hypobaric Solutions for Unilateral Spinal Anesthesia

22. A Low-Dose Bupivacaine: A Comparison of Hyperbaric and Hypobaric Solutions for Unilateral Spinal Anesthesia
the total amount of local anesthetic molecules injected into the spinal canal appears to be the more important factor
In patients for whom lying on the operative site is impossible, using a hypobaric solution would be preferable.

23. Conclusion Heavy & Hypobaric : 也許比plain更好預測麻醉的高度 側躺的方式可減少一些CV 方面的變化
考慮用Hypobaric , dose 要減低
用Hypobaric 的方式 , 可能可延長麻醉的時間

24. THANKS FOR YOUR ATTENTION !!!