Consider Continuous Paravertebral Block as Your Primary Analgesic Technique



Consider Continuous Paravertebral Block as Your Primary Analgesic Technique


Bruce Ben-David MD



SCENARIO

Your colleagues who are surgeons and your hospital administration are increasingly pushing the limits on what can be done as an ambulatory surgical procedure. Plans are now taking shape to perform mastectomies as same-day surgery. You are asked for your input into realizing this goal.


CONSIDERATIONS

Although the anesthetic can be done appropriately to achieve rapid recovery, the two primary problems to be expected in discharging these patients are pain and postoperative nausea and vomiting (PONV). These problems are not unrelated. Postoperative pain can itself lead to PONV, and so can its treatment with opiates. In fact, we now know that opiate side effects are linearly correlated with opiate consumption. Since this is a very painful procedure, we can anticipate significant need for opiate analgesics postoperatively.

We also know that opiates may adequately control pain at rest but, because of limited mu-agonist-receptor participation in the relevant pathways, they are less effective in controlling pain with movement. Opiates alone therefore may be insufficient to get patients mobilized and discharged home. Moreover, we cannot ignore the significant correlation between severe postoperative pain and the development of persistent or chronic postoperative pain. This is a serious concern in mastectomy surgery; a high percentage of patients having mastectomy develop chronic pain known as “postmastectomy syndrome.” Trying to shuffle our patients quickly out of the hospital without aggressively addressing pain management beyond the immediate hours after surgery clearly is not only likely to fail in the short term but also in the long term.


OPTIONS

Multiple intercostal blocks or local-anesthetic wound infiltration can be expected to provide analgesia of only limited duration. A “soaker” catheter infusing local anesthetic into the wound may add modestly to the analgesia, but the technique generally has not been shown to provide the same level of analgesia as do neural-blockade techniques.


The most commonly used neural-blockade technique today for procedures of the thorax and abdomen is thoracic epidural analgesia (TEA). While TEA can be expected to provide analgesia far superior to that possible with patient controlled analgesia (PCA) opiate, it is not a practicable solution here. TEA use is associated with several side effects, some of them quite common, which render the technique unacceptable for the ambulatory surgical patient. These side effects include pruritis, urinary retention, nausea and vomiting, respiratory depression, and hypotension. Though probably not relevant here, TEA use is a particular concern in the patient who will be administered anticoagulants postoperatively. In the United States, epidural hematoma has rendered dozens of patients paraplegic when, postoperatively, low-molecular-weight heparin was administered in conjunction with the use of epidural analgesia.

An alternative technique of neural blockade, continuous paravertebral block (CPVB), is at least as effective an analgesic as TEA but is nearly devoid of TEA’s side effects. Originally described more than 100 years ago, paravertebral block has found renewed popularity in recent years and has proven most useful as a continuous technique. Its advantages include its ability to achieve a high degree of sensory and analgesic blockade without causing urinary retention, respiratory depression, pruritis, or hypotension. In addition, CPVB better preserves forced vital capacity (FVC) following thoracotomy. It preserves lower-limb strength, thus facilitating early mobilization of patients. It affords the possibility of unilateral or bilateral blockade, as needed. Lastly, its offset from the midline promises less risk of spinal cord injury as a result of either needle trauma or hematoma. In fact, a second and newer technique of CPVB, the lateral intercostal approach, is even feasible in situations of coagulopathy, spine abnormality, or spinal trauma.

Jul 1, 2016 | Posted by in ANESTHESIA | Comments Off on Consider Continuous Paravertebral Block as Your Primary Analgesic Technique
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