The brachial plexus block rationale is based on the existence of a well-defined fascia running from the cervical processes to the armpit and on the free diffusion of the injected anaesthetic solution along this fascia. The volume of the injected anaesthetic solution may determine the quality of the anaesthetic cover .
The aim of this study was to compare two groups of patients scheduled for shoulder capsuloplasty who underwent a Winnie interscalene brachial plexus block  followed by a Pippa proximal cranial needle approach . The combination of two anaesthetic approaches [4–7] was employed to overcome the septa obstacles and to fill as much as possible of the interscalene sheath, independently from the quantity of the anaesthetic solution. The dose of anaesthetic employed was constant, while volume and concentration differed between the two groups in order to assess the effect of anaesthetic volume and concentration on the motor and sensory block and to see the effect of the anaesthetic solution on the sympathetic fibres.
After local Ethics Committee approval 60 fully consented American Society of Anesthesiologists (ASA) physical status I–II patients, whose age ranged from 20 to 65 yr and weight from 50 to 80 kg (Table 1), received regional anaesthesia for shoulder capsuloplasty. A Winnie interscalene brachial plexus block was performed (Fig. 1) and followed by Pippa proximal cranial needle block (Fig. 2) and a constant dose of anaesthetic was administered: 300 mg of lidocaine and 75 mg of bupivacaine.
Patients were randomly assigned to two different groups of 30 patients according to the employed volume: Group I received 60 mL of anaesthetic solution made of equal parts of bupivacaine 0.25% (with 150 μg epinephrine, i.e. 2.5 μg mL−1) and lidocaine 1% while Group II received 30 mL of anaesthetic solution with equal parts of bupivacaine 0.50% (with 150 μg epinephrine, i.e. 5 μg mL−1) and lidocaine 2%. The volume of local anaesthetic administered was divided in equal parts in the two approaches (i.e. 30 mL in each approach in Group I and 15 mL in each approach in Group II).
The block was performed at least 30 min before surgery; 20 min before the block patients were given 10 mg of oral diazepam and 0.5 mg of intramuscular atropine. In each group the nerve block was performed with the aid of a nerve stimulator using a short bevelled, 5 cm, 22-G Teflon-coated stimulating needle (Stimuplex, B Braun Melsungen AG, Germany).
According to the Winnie technique  the needle was introduced in the caudal direction at the intersection point between the external jugular vein and the intercricothyroided line (Fig. 1). The Pippa proximal cranial needle block was then performed: the needle was introduced in a cranial direction from the midpoint between the clavicle bone insertion of the sternocleidomastoid muscle and the external jugular vein towards Chaissignac's tubercle with a 30° angle upon the upper border of the clavicle (Fig. 2).
The nerve stimulator was set at 2 Hz, while the intensity of the stimulating current was initially set to deliver 1 mA and then gradually decreased to <0.5 mA.
Flexion or extension of the wrist, elbow or fingers confirmed that the needle was close to the brachial plexus nerve fibres.
The patients were evaluated by an assessor, blinded to the procedure employed, 10, 20 and 30 min after injection of the anaesthetic solution.
Motor function was tested according to the modified Bromage scale .
Sensory block was tested by pinprick response in the following eight areas:
- Lateral region of the neck, innervated by the cutaneous nerve of the neck (C2–C4).
- Lateral region of the arm, innervated by the superior cutaneous nerve of the arm, branch of the axillary nerve (C5–C6).
- Lateral region of the forearm, innervated by the lateral cutaneous nerve of the forearm, branch of the musculocutaneous nerve (C5–C6–C7).
- Medial side of the forearm, innervated by medial cutaneous nerve of the forearm (C8–T1).
- Medial aspect of the arm, innervated by the medial cutaneous nerve of the arm (T1) and the intercostobrachialis nerve (T1–T2).
- Dorsal areas of the hand in the region supplied by the radial nerve (C5, C6, C7).
- Palmar areas of the hand in the region supplied by the median nerve (C6, C7, C8, T1).
- Ulnar territory of the hand (C7, C8, T1).
The degree of analgesia was graded as follows:
0: pinprick clearly felt as painful, evoking a visible reaction;
1: pinprick attenuated, non-visible reaction to the stimulus;
2: pinprick felt only as a tactile, not painful stimulus;
3: pinprick not felt at all.
The onset of the surgical anaesthesia was defined as the loss of pinprick sensation at the skin dermatomes involved in the surgical field (from C4 to C7) with the inability to elevate the operated limb from the bed .
Anaesthesia was clinically classified as:
Excellent: patient appeared completely satisfied and comfortable with the procedure.
Good: analgesia was complete, but the patient complained about the position of the arm and/or the length of the procedure necessitating intraoperative intravenous (i.v.) medication.
Insufficient: analgesia was incomplete and additional nerve block and/or i.v. analgesic (fentanyl) was required.
Failure : analgesia was insufficient and general anaesthesia had to be performed.
Ultrasonography was chosen as the method to demonstrate diaphragmatic movement as it reliably shows paradoxical movement of the diaphragm in the event of paresis .
Before and 10 min after the block all the patients underwent ultrasonography to assess diaphragmatic movement on deep inspiration. The ultrasound probe was placed over one of the lower intercostals spaces in the mid-axillary line in order to visualize the dome of the diaphragm on the same side as the block. Diaphragmatic paresis was defined as a 50% reduction of the diaphragmatic excursion .
Statistical differences between the two groups were assessed according to the Fisher's exact test. Level of significance was set at P < 0.05.
The level of analgesia obtained in each group is shown in Table 2. In Group I the postaxial regions of the medial arm and forearm, supplied by the medial cutaneous arm, forearm and ulnar nerve, were blocked. The areas supplied by median and radial nerves were blocked as well.
Clinical outcome of anaesthesia is shown in Table 3.
Grade II motor block was achieved on average in 25 (range 20–29) and 15 (range 11–19) min in Groups I and II, respectively (P < 0.05).
Minor complications, due to the distribution of the anaesthetic solution to nearby structures, occurred only in Group II and included: dysphonia due to laryngeal nerve involvement (20 patients) and Horner's syndrome (18 patients). All these complications spontaneously resolved within 40 min.
Major complications were observed only in Group II and included bradycardia (heart rate (HR) <45 min−1) and hypotension (systolic arterial pressure <70 mmHg) in the sitting position  and phrenic nerve paresis  in 66%, 66% and 27% of the patients, respectively.
The main finding of this investigation was that the quality of the anaesthetic block and the incidence of complications strictly depends on the volume and the concentration of the anaesthetic solution. The quality of anaesthesia obtained at the surgical site was excellent in all the patients. The two groups showed a different distribution of anaesthesia in the areas not interested by the surgical procedure. In Group II insufficient anaesthesia was regularly obtained in the areas supplied by the medial cutaneous arm and forearm, ulnar, median and radial nerves.
Several anatomic and clinical studies [14,15] demonstrated the existence of fibrous septa within the sheath of the brachial plexus dividing it into compartments, which may lead to inadequate diffusion of the anaesthetic solution . Furthermore, the author has clinically demonstrated a preferential distribution of the anaesthetic solution injected into the perivascular axillary sheath , which could be explained by the trapping of the anaesthetic solution in separate compartments, and its spread along a preferential route in relation to the direction of the needle. These observations were the rationale for a double approach which allowed a combined craniocaudal (Winnie technique) and caudocranial (Pippa's technique) distribution of the anaesthetic solution (Fig. 3). Routine use of nerve stimulators and the peculiar inclination of short bevelled needles in both approaches preserves the safety of the technique. The dose of the anaesthetic injected (300 mg lidocaine +75 mg bupivacaine) was constant, while volume varied between the two groups. The onset of surgical anaesthesia required 25 ± 5 min in Group I and 20 ± 5 min in Group II. It is known that the latency of the anaesthetic block related to the concentration, the quicker minimum effective concentration will be reached inside the nerve fibre, so reducing latency time . As reported also by other authors , increased analgesia was observed in patients who were given higher volumes (60 mL).
In Group II, phrenic nerve paresis was observed in 27% of cases. Phrenic nerve paresis has been reported as possible complication of supraclavicular block with varying incidence from 28% to 80%. Urmey and colleagues  reported ipsilateral hemidiaphragmatic paresis in 100% of patients during interscalene block and argued that phrenic paresis should be considered as an expected side-effect rather than a complication of the block . In our series and with the same investigational technique only 27% of the patients in Group II were found to have a diaphragmatic paresis. Only two patients experienced respiratory symptoms (dyspnea) for <10 min; none of them showed respiratory distress and in all the cases SPO2 remained unchanged. The fact that no phrenic paresis has been recorded in Group I can be ascribed to the lower concentration of anaesthetic employed.
Several authors [12,20–22] have investigated bradycardia and hypotension in upper limb surgery in the sitting position. The nearest hypothesis includes a combination of (a) peripheral vasodilatation due to the block exaggerated by the sitting position, (b) increased heart contractility secondary to absorbed epinephrine from the block, (c) vigorous contraction of an empty ventricle and (d) vagal dominance [23–25]. In our series 66% of the patients in Group II showed hypotension and bradycardia with pre-syncopal symptoms. In all the patients the symptoms resolved with elevation of the legs, i.v. fluid infusion, i.v. administration of sympathomimetic and anticholinergic drugs such as atropine or with a combination of all three measures.
No major complications occurred in Group I, likely because the reduction of the concentration of anaesthetic solution causes less involvement of the sympathetic fibres and phrenic nerve.
In conclusion, the quality of anaesthesia at the surgical site obtained in both groups was excellent. In non-surgical areas different levels of anaesthesia were achieved in the two groups: patients in Group I had a wider anaesthesia due to the larger diffusion of the solution within the brachial plexus. Major complications were observed only in those patients who received high concentration and small volume of local anaesthetic. High concentration of local anaesthetic on brachial plexus motor and sensory fibres affects block intensity and ensure an excellent anaesthetic cover; on the other hand major clinical complications due to sympathetic fibre block may occur and require sudden intervention. High volumes and small concentration of local anaesthetic in the brachial plexus avoid major complications such as phrenic nerve involvement and vagal reflexes.
1. Winnie AP, Radonjic R, Akkineni SR, Durrani Z. Factors influencing distribution of local anaesthetic injected into the brachial plexus sheath. Anesth Analg
2. Winnie AP. Interscalene brachial plexus block. Anesth Analg
3. Pippa P. Brachial plexus block using a new subclavian perivascular technique: the proximal cranial needle approach. Eur J Anaesth
4. Turkan H, Baykal B, Ozisik T. Axillary brachial plexus blockade: an evaluation of three techniques. Mil Med
5. Delgado Tapia JA, Garcia Sanchez MJ, Prieto Cuellar M, Jimenez Ayala I, Garcia Rescalvo MA, Lopez-Andrade Jurado A. Infraclavicular brachial plexus block using a multiple injection technique and an approach in the cranial direction in a patient with anticipated difficulties in tracheal intubation. Rev Esp Anestesiol Reanim
(2): 105–107 [in Spanish].
6. Fanelli G, Casati A, Garancini P, Torri G. Nerve stimulator and multiple injection technique for upper and lower limb blockade: failure rate, patient acceptance and neurologic complication. Study group of regional Anesthesia. Anesth Analg
7. Urmey WF. Combined axillary-interscalene (axis) brachial plexus block for elbow surgery. Reg Anesth
8. Bromage PR. Epidural Analgesia
. Philadelphia, PA: W. Saunders, 1978: 144.
9. Casati A, Fanelli G, Cedrati V, Berti M, Aldegheri G, Torri G. Pulmonary function changes after interscalene brachial plexus anaesthesia with 0.5% and 0.75% ropivacaine: a double-blind comparison with 2% mepivacaine. Anesth Analg
10. Cohen E, Mier A, Heywood P, Murphy K, Boultbee J, Guz A. Excursion volume relation of the right hemidiaphragm measured by ultrasonography and respiratory airflow measurements. Thorax
11. Neal JM, Moore JM, Kopacz DJ, Liu SS, Kramer DJ, Plorde JJ. Quantitative analysis of respiratory, motor and sensory function after supraclavicular block. Anesth Analg
12. D'Alessio JG, Weller RS, Rosenblum M. Activation of the Bezold–Jarisch reflex in the sitting position for shoulder arthroscopy using interscalene block. Anesth Analg
13. Urmey WF, Talts KH, Sharrock NE. One hundred percent of hemidiaphragmatic paresis associated with interscalene brachial plexus anaesthesia as diagnosed by ultrasonography. Anesth Analg
14. Thomson GE, Rorie DK. Functional anatomy of the brachial plexus sheath. Anesthesiology
15. Partridge BL, Katz J, Bernischke K. Functional anatomy of brachial plexus sheath implication for anaesthesia. Anesthesiology
16. Vester-Andersen T, Christiansen C, Sorensen M, Eriksen C. Perivascular axillary block: blockade following 40 ml 1% mepivacaine with adrenaline. Acta Anesthesiol Scand
17. Pippa P, Rucci FS. Preferential channelling of anaesthetic solution injected within the perivascular axillary sheath. Eur J Anaesthesiol
18. De Jong RH. Local Anaesthetic
. St. Louis: Mosby Year book Inc., 1991.
19. Urmey WF, McDonald M. Hemidiaphragmatic paresis during interscalene brachial plexus block: effect on pulmonary function and chest wall mechanism. Anesth Analg
20. Kahn RI, Hargett MJ. Beta-adrenergic blockers and vasovagal episodes during shoulder surgery in the sitting position under interscalene block. Anesth Analg
21. Liguori GA, Kahn RI, Gordon J, Gordon MA, Urban MK. The use of metoprolol and glycopyrrolate to prevent hypotensive-bradycardic events during shoulder arthroscopy in the sitting position under interscalene block. Anesth Analg
22. Morris GN. The Bezold–Jarisch reflex. Anesth Analg
23. Stienstra R. Mechanism behind and treatment of sudden, unexpected circulatory collapse during central neuraxis blockade. Acta Anaesthesiol Scand
24. McCrae AF, Wildsmith JAW. Prevention and treatment of hypotension during central neural block. Br J Anaesth
25. Campagna JA, Carter C. Clinical relevance of the Bezold– Jarisch reflex. Anaesthesiology