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Correspondence  |   July 2002
Interscalene Block-, Sedation-, Lateral Positioning-, and Hydralazine-induced Hypotension: Is It Really Prudent?
Author Affiliations & Notes
  • Didier Sciard, M.D.
    *
  • * The University of Texas Medical School at Houston, Houston, Texas.
Article Information
Correspondence
Correspondence   |   July 2002
Interscalene Block-, Sedation-, Lateral Positioning-, and Hydralazine-induced Hypotension: Is It Really Prudent?
Anesthesiology 7 2002, Vol.97, 280-281. doi:
Anesthesiology 7 2002, Vol.97, 280-281. doi:
To the Editor:—
It was with interest that we read the case report presented by Anil S. Ranawat et al.  1 in the November issue of Anesthesiology. We would like to raise a number of points.
We understand that the author selected this anesthesia technique to decrease blood loss during the procedure and for postoperative pain management.
Although the vast majority of our orthopedic patients also benefit from the use of peripheral nerve blocks for anesthesia supplemented by sedation, we questioned the use of a hypotensive technique (mean arterial pressure of 55 mmHg) without any control of ventilation–perfusion parameters (ETco2not monitored) in a patient with risk of intraoperative loss of a large volume of blood, especially in the lateral position.
In this moderately obese patient (95 kg, 1.70 m), an interscalene block that had induced a phrenic nerve block 2 and consequently an alteration in his respiratory function 3 combined with the lateral position and the use of sedation (100 μg/h fentanyl, 200 mg/h propofol) further increase the risk for peroperative respiratory failure. 4 Furthermore, the patient positioning makes the management of the airway difficult in case of a required intubation. 5 It seems that in this specific situation, a peripheral nerve block combined with general anesthesia would be more appropriate.
It is also important to recognize that an infraclavicular block instead of the reported interscalene would have represented a better alternative because infraclavicular blocks are not associated with a block of the phrenic nerve and consequently do not affect pulmonary function to the same extent as an interscalene block. 6 Finally, it is unfortunate that the authors chose a single injection block and did not consider the placement of a perineural catheter for the management of pain postoperatively, despite numerous demonstrated benefits of such a technique, 7 since most of these patients experience moderate to severe pain well over 24 h.
References
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Urmey WF, Talts KH, Sharrock NE: One hundred percent incidence of hemidiaphragmatic paresis associated with interscalene brachial plexus anesthesia as diagnosed by ultrasonography. Anesth Analg 1991; 72: 498–503Urmey, WF Talts, KH Sharrock, NE
Drummond GB: Interscalene block and pulmonary function. Anesth Analg 1993; 76: 675–6Drummond, GB
Kempen PM, O'Donnell J, Lawler R, Mantha V: Acute respiratory insufficiency during interscalene plexus block. Anesth Analg. 2000; 90: 1415–6Kempen, PM O'Donnell, J Lawler, R Mantha, V
Gentili ME, Lefoulon-Gourves M, Mamelle JC, Bonnet F: Acute respiratory failure following interscalene block: Complications of combined general and regional anesthesia. Reg Anesth 1994; 19: 292–3Gentili, ME Lefoulon-Gourves, M Mamelle, JC Bonnet, F
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Borgeat A, Perschak H, Bird P, Hodler J, Gerber C: Patient-controlled interscalene analgesia with ropivacaine 0.2%versus  patient-controlled intravenous analgesia after major shoulder surgery: Effects on diaphragmatic and respiratory function. A nesthesiology 2000; 92: 102–8Borgeat, A Perschak, H Bird, P Hodler, J Gerber, C