Anterior cervical approach for stellate ganglion and T2 to T3 sympathetic blocks: a novel technique.

BACKGROUND: Stellate ganglion block is used for the diagnosis and treatment of sympathetically maintained pain syndromes. Multiple anatomic variations and inaccurate sympathetic block may mislead the diagnosis and prevent patients from receiving potentially beneficial interventions. We describe a novel approach to blockade of the sympathetic chain at C7 and at T2 to T3 with a single-needle injection. TECHNIQUE: With the patient in supine position, the uncinate process of C7 is identified fluoroscopically as a target for insertion of a catheter through a Touhy needle. The catheter is directed caudally to the junction of T2 and T3. Contrast injection confirms the spread to the appropriate levels before injection of local anesthetic. CONCLUSION: This novel approach to blockade of the upper extremity sympathetic innervation may enhance diagnostic accuracy and therapeutic benefit as compared with traditional approaches to the stellate ganglion alone. This approach may be expected to decrease the risk of pneumothorax when compared with the posterior approach to T2 to T3.

Pitfalls of opioid rotation: substituting another opioid for methadone in patients with cancer pain.

The successful use of methadone in cancer pain has been supported by numerous case reports and clinical studies. Methadone is usually used as a second or third line opioid medication. As the use of methadone increases we are facing the challenge of converting methadone to other opioids as part of sequential opioid trials. Data on the equianalgesic ratios for the substitution of other opioids for methadone are lacking. We present prospective data on 13 consecutive rotations from methadone to a different opioid. The opioid rotation was followed by escalation of pain and/or severe dysphoria, not controlled by a rapid increase in the dose of the second opioid, in 12 of the 13 patients. Only one patient was successfully maintained on the second opioid after the discontinuation of methadone, while 12 patients required a switch back to methadone. We conclude that opioid rotation from methadone to another opioid is often complicated by worsening pain and dysphoria. These symptoms may not improve despite upward titration of the second opioid. A uniformly accepted conversion ratio for substituting methadone with another opioid is currently not available. More data on the rotation from methadone to other opioids are needed.

QTc interval prolongation associated with intravenous methadone.

Numerous medications prolong the rate-corrected QT (QTc) interval and induce arrhythmias by blocking ionic current through cardiac potassium channels composed of subunits expressed by the human ether-a-go-go-related gene (HERG). Recent reports suggest that high doses of methadone cause torsades de pointes. To date, no controlled study has described an association between methadone and QTc prolongation. The only commercial formulation of parenteral methadone available in the United States contains the preservative chlorobutanol. The objectives of this study are to determine: (1) whether the administration of intravenous (i.v.) methadone causes QTc prolongation in humans; (2) whether methadone and/or chlorobutanol block cardiac HERG potassium currents (IHERG) in vitro. Over 20 months, we identified every inpatient with at least one electrocardiogram (ECG) performed on i.v. methadone. For each patient, we measured QTc intervals for every available ECG performed on and off i.v. methadone. Concurrent methadone doses were also recorded. Similar data were collected for a separate group of inpatients treated with i.v. morphine. In a separate set of experiments IHERG was evaluated in transfected human embryonic kidney cells exposed to increasing concentrations of methadone, chlorobutanol, and the two in combination. Mean difference (+/- standard error) per patient in QTc intervals on and off methadone was 41.7 (+/- 7.8)ms, p<0.0001. Mean difference in QTc intervals on and off morphine was 9.0 (+/- 6.1)ms, p=0.15. The approximately linear relationship between QTc measurements and log-dose of methadone was significant (p<0.0001). Methadone and chlorobutanol independently block IHERG in a concentration-dependent manner with IC50 values of 20 +/- 2 microM and 4.4 +/- 0.3 mM, respectively. Chlorobutanol potentiates methadone's ability to block IHERG. Methadone in combination with chlorobutanol is associated with QTc interval prolongation. Our data strongly suggest that methadone in combination with chlorobutanol is associated with QTc interval prolongation.

Benefit-risk assessment of transdermal fentanyl for the treatment of chronic pain.

Transdermal fentanyl is effective and well tolerated for the treatment of chronic pain caused by malignancy and non-malignant conditions when administered according to the manufacturer's recommendations. Compared with oral opioids, the advantages of transdermal fentanyl include a lower incidence and impact of adverse effects (constipation, nausea and vomiting, and daytime drowsiness), a higher degree of patient satisfaction, improved quality of life, improved convenience and compliance resulting from administration every 72 hours, and decreased use of rescue medication. Transdermal fentanyl is a useful analgesic for cancer patients who are unable to swallow or have gastrointestinal problems. Transdermal fentanyl forms a depot within the upper skin layers before entering the microcirculation. Therapeutic blood levels are attained 12-16 hours after patch application and decrease slowly with a half-life of 16-22 hours following removal. Patients with chronic pain should be titrated to adequate relief with short-acting oral or parenteral opioids prior to the initiation of transdermal fentanyl in order to prevent exacerbations of pain or opioid-related adverse effects. Transdermal fentanyl can then be initiated based on the 24-hour opioid requirement once adequate analgesia has been achieved. The prolonged elimination of transdermal fentanyl can become problematic if patients develop opioid-related adverse effects, especially hypoventilation. Adverse effects do not improve immediately after patch removal and may take many hours to resolve. Patients who experience opioid-related toxicity associated with respiratory depression should be treated immediately with an opioid antagonist such as naloxone and closely monitored for at least 24 hours. Because of the short half-life of naloxone, sequential doses or a continuous infusion of the opioid antagonist may be necessary. Transdermal fentanyl should be administered cautiously to patients with pre-existing conditions such as emphysema that may predispose them to the development of hypoventilation. Transdermal fentanyl is indicated only for patients who require continuous opioid administration for the treatment of chronic pain that cannot be managed with other medications. It is contraindicated in the management of acute and postoperative pain, as pain may decrease more rapidly in these circumstances than fentanyl blood levels can be adjusted, leading to the development of life-threatening hypoventilation. Cognitive and physical impairments such as confusion and abnormal co-ordination can occur with transdermal fentanyl. Therefore, patients should be instructed to refrain from driving or operating machinery immediately following the initiation of transdermal fentanyl, or after any dosage increase. Patients may resume such activities once the absence of these potential adverse effects is documented.

Olanzapine in the management of cancer pain.

In cancer patients, cognitive impairment, psychological distress, and anxiety may accompany and aggravate pain. Neuroleptics are frequently used to control these symptoms and may be used to treat pain that has been unresponsive to more conventional approaches. Because of prominent side effects of traditional neuroleptics and conflicting data regarding their analgesic efficacy, their use in the treatment of pain remains controversial. Olanzapine, an atypical neuroleptic, might offer advantages because of its safer side effect profile. It has also been shown to have an independent antinociceptive activity in animals. The use of olanzapine in the management of cancer pain has not been previously described. We prospectively collected the data on 8 cancer patients with severe pain, uncontrolled in spite of aggressive opioid titration, who received olanzapine to treat severe anxiety and mild cognitive impairment. Patients did not meet criteria for delirium and their cognitive impairment was defined as cognitive disorder not otherwise specified (NOS) according to DSM-IV. Patients received 2.5 to 7.5 mg of olanzapine daily. In all patients, opioid requirements had escalated rapidly prior to starting olanzapine. Levels of pain, sedation, and opioid use were measured 2 days before and 2 days after olanzapine was started. Cognitive state was assessed daily. All 8 patients had marked reduction of the daily pain scores. The average daily opioid use decreased significantly in all patients. Cognitive impairment and anxiety resolved within 24 hours of initiating olanzapine. In these 8 patients, decreased pain scores and opioid requirements may have resulted from improvement in cognitive function and the known anxiolytic effect of olanzapine. Other mechanisms may include independent or adjuvant analgesic effects of olanzapine. We conclude that olanzapine may be useful in the treatment of patients with uncontrolled cancer pain associated with cognitive impairment or anxiety. Further studies to evaluate possible analgesic effect of olanzapine are needed.

Perioperative immunosuppression in cancer patients.

Cancer patients commonly undergo surgical procedures. The perioperative period is characterized by immunosuppression and may predispose already immunosupressed cancer patients to tumor spread. Cancer patients typically show depression of both cellular and humoral immune functions. Possible mediating factors for immunosuppression during the perioperative period include anesthetic agents, opioids, surgery, blood transfusions, temperature changes, pain, and psychological stress. A surgically mediated decrease in natural killer (NK) cell activity has been implicated as the major contributing factor associated with an increase in metastasis. The decreased NK cell activity during the perioperative period is associated with increased risk of mortality and cancer. Commonly used anesthetic agents and opioids are known to inhibit NK cell activity. Despite the in vivo evidence of anesthetic- and analgesic-agent-mediated immunosupression, surgery by itself results in a three- to four-fold increase in retention of metastasis when compared to the groups in which anesthesia and analgesia were combined. The negative consequences associated with perioperative immunosuppression may be decreased by several strategies, including aggressive pain control, selection of specific anesthetic and analgesic agents, avoidance of unnecessary transfusions, and delay of elective surgeries until the patient's nutritional and immune status is optimized. Recognizing and neutralizing its mediating factors, perioperative immunosuppression in cancer patients may be reduced.

Respiratory distress after intrathecal baclofen withdrawal.

We present the case of a 19-yr-old woman with a history of generalized dystonia who developed sudden onset of adductor spasms of the vocal cords and increased dystonia after the interruption or intrathecal baclofen therapy. Her symptoms resolved after intrathecal baclofen was restored. In patients with dystonia receiving intrathecal baclofen therapy, the onset of dyspnea associated with increased muscle tone should prompt the investigation of baclofen withdrawal.

A safe and effective method for converting patients from transdermal to intravenous fentanyl for the treatment of acute cancer-related pain.

BACKGROUND: The delayed effects (12-16 hours) of transdermal fentanyl make dose titration difficult during acute exacerbations of cancer pain. Patients at the authors' institution routinely are switched from transdermal to intravenous (IV) fentanyl using a 1:1 (transdermal:IV) conversion during severe episodes of pain. METHODS: The authors evaluated nine consecutive hospitalized patients with cancer who had severe pain for up to 6 days following the conversion from transdermal to IV fentanyl. Pain intensity was rated using an 11-point (0-10) verbal numeric rating scale (NRS). All 9 patients initially reported their pain intensity with movement as >or= 8 during treatment with transdermal fentanyl. Eight patients initially reported their pain at rest as >or= 8. In each patient, all transdermal patches were removed, and a continuous infusion (CI) delivering IV fentanyl at the same hourly rate was initiated simultaneously. Demand boluses of IV fentanyl equivalent in dosage to 50-100% of the CI rate remained available by patient-controlled analgesia (PCA). Pain intensity (0-10), sedation (0-3), and hourly fentanyl requirements (micrograms per hour) were assessed and recorded immediately prior to patch removal and at least once daily after the initiation of IV fentanyl. The CI and demand boluses were titrated whenever necessary on the basis of pain intensity and supplemental PCA use. RESULTS: All 9 patients reported mild levels (