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Correspondence |
University Hospital Maison Blanche, Reims, France, E-mail: jmmalinovsky{at}chu-reims.fr
To the Editor:
In our institution, as in many others, surgery on the proximal part of upper arm is usually performed under interscalene brachial plexus block (ISB) with general anesthesia (GA) upon request of the surgeon. We recently experienced three cases of delayed respiratory distress after complete recovery of uneventful anesthesia in geriatric patients who received ISB and GA for surgeries on the upper arm or shoulder. In all cases ISB was performed using a nerve stimulator at first attempt by the Winnie approach.
In the first case, a 74-yr-old female received ISB with a 30 mL mixture containing ropivacaine 112 mg and lidocaine 150 mg with epinephrine, injected slowly in divided doses. Ten minutes later, GA was administered with sufentanil, propofol, sevoflurane and atracurium to facilitate tracheal intubation. At completion of surgery performed without supplemental opioids, the patient recovered fully from GA and her trachea was extubated 130 min after ISB. However, within ten minutes, she began to sweat and became dyspneic, breathing at 34 min–1, and paradoxical thoracoabdominal movements on the ipsilateral side of ISB were noted. Documentation of motor and sensory block isolated to the repaired arm excluded any neuraxial extension of anesthesia. The trachea was re-intubated to facilitate ventilation for two hours after which time the block regressed sufficiently to allow spontaneous respiration and full recovery. In the second case, a 90-yr-old female received 20 mL of 0.25% bupivacaine for ISB under similar conditions. Her trachea was extubated 175 min after ISB and 20 min later, she became dyspneic with paradoxical movements. As supplemental oxygen administered via a facial mask was ineffective to maintain adequate saturation, she was mechanically ventilated for an additional 12 hr. In the third case, a 72-yr-old female received 20 mL of 0.2% ropivacaine for ISB. Her trachea was extubated 90 min after regional anesthesia and 15 min later, respiratory insufficiency appeared with paradoxical chest movements. In her case, supplemental oxygen administered via face mask for three hours was effective to maintain SpO2 > 95%.
As the phrenic nerve is in the vicinity of brachial plexus nerves at the interscalene level, the incidence of phrenic nerve block approaches 100% of cases, whatever technique of nerve location is used.1 For anatomical reasons, digital pressure is ineffective in reducing the incidence of diaphragm paresis after ISB.2–4 Healthy patients generally compensate for unilateral diaphragmatic paralysis by recruiting accessory respiratory and abdominal muscles. Therefore, changes in respiratory function after ISB are usually asymptomatic5 because efficient negative intrathoracic pressure can be generated by only one half of the diaphragm. In the present cases, accessory respiratory muscle function was insufficient to compensate for phrenic nerve block. This may partly be explained by aging, and residual effects of GA despite the low doses of anesthetics used. As all three patients presented delayed paradoxical movements of abdominal muscles related to prolonged diaphragmatic paralysis on the side of the ISB, effects of aging and local anesthetics on the phrenic nerve cannot be ruled out. Others have also reported delayed pulmonary dysfunction after ISB in awake patients6 as well as in anesthetized patients.7 In our series, it is likely that controlled ventilation during the surgical procedure protected the patients from respiratory insufficiency, which occurred in the early postoperative period due in part, to the low muscle masses and limited pulmonary reserves of these elderly patients. Finally, these cases highlight the fact that onset of respiratory insufficiency related to ISB may be delayed in the elderly, occurring several hours after performing the block, especially when patients are anesthetized for surgery.
Footnotes
Accepted for publication September 6, 2005.
References
1 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: 498–503.
2 Sala-Blanch X, Lazaro JR, Correa J, Gomez-Fernandez M. Phrenic nerve block caused by interscalene brachial plexus block: effects of digital pressure and a low volume of local anesthetic. Reg Anesth Pain Med 1999; 24: 231–5.[Medline]
3 Urmey WF, Grossi P, Sharrock NE, et al. Digital pressure during interscalene block is clinically ineffective in preventing anesthetic spread to the cervical plexus. Anesth Analg 1996; 83: 366–70.[Abstract]
4 Bennani SE, Vandenabele-Teneur F, Nyarwaya JB, Delecroix M, Krivosic-Horber R. An attempt to prevent spread of local anaesthetic to the phrenic nerve by compression above the injection site during the interscalene brachial plexus block. Eur J Anaesthesiol 1998; 15: 453–6.[Medline]
5 Borgeat A, Ekatodramis G, Kalberer F, Benz C. Acute and nonacute complications associated with interscalene block and shoulder surgery: a prospective study. Anesthesiology 2001; 95: 875–80.[Medline]
6 Kayerker UM, Dick MM. Phrenic nerve paralysis following interscalene brachial plexus block. Anesth Analg 1983; 62: 536–7.
7 Ono T, Hayashi K, Takahashi H, Sakio H. A case report of hemidiaphragmatic paresis caused by interscalene brachial plexus block (Japanese). Masui 2002; 51: 899–901.[Medline]
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