Pain evaluation in patients receiving intravenous patient-controlled analgesia after surgery.

STUDY OBJECTIVE: To evaluate the effectiveness of intravenous patient-controlled analgesia (PCA) in patients after surgery. DESIGN: Prospective, observational study. SETTING: University teaching hospital. PATIENTS: Sixty patients with American Society of Anesthesiologists physical status I-III receiving intravenous PCA for postoperative pain. The PCA was programmed to deliver morphine 1 mg or hydromorphone 0.1-0.2 mg, with a lockout interval of 10 and 6 minutes for 80% and 20% of the patients, respectively. MEASUREMENTS AND MAIN RESULTS: Patients were asked, up to 4 times during PCA use and once within 4 hours after PCA use, to describe and rate their intensity of pain at rest and after activity. During the first 12 hours of intravenous PCA use, 75% of the patients reported moderate-to-severe pain > or = 5 on a verbal numeric rating scale) at rest, 80% after activity. Corresponding values, respectively, were 33% and 72% for the 12-24-hour period, 43% and 76% for the 24-36-hour period, and 36% and 64% for the 36-48-hour period of intravenous PCA use. Within 4 hours of stopping PCA, 30% and 58% of the patients had moderate-to-severe pain at rest and after activity, respectively. In approximately 50% of patients, presence of pain was described with words signifying sensory and affective dimensions of pain. Pain control was rated as good or very good by 54% of patients during the first 12 hours of intravenous PCA. Ratings of pain control tended to improve with time. CONCLUSION: Successful postoperative pain management using PCA is difficult to achieve on a consistent basis unless treatment is individualized. Our data support the hypothesis that small fixed doses fail to achieve adequate relief in many patients.

The number of injections does not influence absorption of bupivacaine after cervical plexus block for carotid endarterectomy.

STUDY OBJECTIVE: To investigate the efficacy and kinetics of bupivacaine when used for deep cervical plexus block (CPB), using either a single-injection or multiple-injections technique. DESIGN: Prospective, randomized, double-blind study. SETTING: Operating room of a university hospital. PATIENTS: Twenty-four adult patients (16 men, 8 women) scheduled for carotid endarterectomy. INTERVENTIONS: Patients were randomly assigned to receive CPB either by a single injection or after 3 injections. Patients in the multiple-injections group received a total dose of 15 mL of 0.5% bupivacaine (5 mL each deposited at C2, C3, and C4 over 2 minutes). Patients in the single-injection group received a single 15-mL injection of 0.5% bupivacaine. After the deep CPB, a superficial CPB was performed with 20 mL of 0.5% bupivacaine in all patients. MEASUREMENTS: An anesthesiologist and a surgeon graded the success of the block. Arterial plasma concentrations of bupivacaine were measured using liquid chromatography-mass spectroscopy. MAIN RESULTS: No significant differences were seen between the 2 groups with respect to the mean peak concentration of bupivacaine (single injection 2314 +/- 1385 ng/mL vs multiple injections 2255 +/- 1105 ng/mL) or time to reach the maximal concentration (time to maximum concentration [single injection 12.1 +/- 7.2 minutes vs multiple injections 12.5 +/- 3.9 minutes]). Furthermore, there were no significant differences in mean block scores between the single-injection and the multiple-injections groups, evaluated either by the anesthesiologists or the surgeon. CONCLUSIONS: The results of this study showed that the absorption of bupivacaine is independent of the number of injections after CPB, and that anesthesia for carotid endarterectomy may be accomplished successfully using either technique.

Analgesic and hemodynamic effects of a single 7.5-mg intravenous dose of morphine in patients with moderate-to-severe postoperative pain.

STUDY OBJECTIVES: To evaluate the analgesic and hemodynamic effects of a single dose of intravenous morphine 7.5 mg in patients experiencing moderate-to-severe postoperative pain, and to determine any gender differences in analgesic response. DESIGN: Randomized, double-blind, parallel-group, multicenter study. SETTING: Postanesthesia care unit of a university teaching hospital. PATIENTS: Eighty-eight patients who underwent total abdominal hysterectomy or prostatectomy. INTERVENTION: Thirty-seven patients received a single dose of morphine sulfate 7.5 mg and 51 patients received placebo, both administered intravenously for 1 minute. MEASUREMENTS AND MAIN RESULTS: Overall, morphine had no significant effect on systolic or diastolic blood pressure, heart rate, oxygen saturation, or respiratory rate. Compared with baseline, morphine significantly reduced pain intensity at 2, 5, and 10 minutes after administration (p<0.05). The difference in pain intensity between patients who received morphine and those who received placebo, however, was significant only at the 5-minute time point (p<0.02). Patients receiving morphine also reported mild pain relief at 2 and 5 minutes after its administration. Peak analgesic effect was reported 2 minutes after its administration in three quarters of the patients. Significant gender differences also were observed in response to analgesic effect. In women, no significant differences in pain intensity were seen at any time between the morphine and placebo groups, whereas in men receiving morphine, pain intensity was significantly less at 2, 5, and 10 minutes compared with baseline and that seen in the placebo group. Women were generally more satisfied with their pain treatment than were men. CONCLUSION: A single 7.5-mg intravenous bolus dose of morphine did not appear to provide adequate reduction in perceived pain intensity in patients with moderate-to-severe postoperative pain. In addition, in contrast to the findings of other experimental pain studies, our data suggest that women are more tolerant of postoperative pain than are men.

Modafinil improves recovery after general anesthesia.

UNLABELLED: Recovery from general anesthesia often involves residual sedation, drowsiness, fatigue, and lack of energy that may last hours to days. Modafinil is a wakefulness-promoting drug approved for patients with excessive daytime sleepiness associated with narcolepsy. We evaluated the effect of single doses of modafinil (200 mg) and placebo in patients recovering from general anesthesia. Thirty-four subjects participated in this prospective, randomized, double-blind study approved by our IRB. Preoperatively, patients were asked to rate various symptoms they had experienced over the previous 24-h using a verbal analog scale (VAS) of 0 to 10 as well as discrete scale when indicated. Postoperatively, once the patient was able to tolerate oral intake and met our institutional discharge criteria, the study drug (modafinil 200 mg or placebo) was administered with a sip of water. Patients were contacted 24 (1) hours after dosing to evaluate postdischarge symptoms. Patients in the placebo group reported significantly more postoperative fatigue (4.8 [3.3] versus 1.4 [1.8]), exhaustion (4.3 [3.3] versus 2.4 [3.1]), or degree of feeling worn out (4.7 [3.6] versus 2.9 [2.4]). Significantly more patients reported moderate to severe fatigue in the placebo group (65% versus 12%). Two major themes of "alertness" and "energy" were expressed by 71% of the patients receiving modafinil versus 18% of those receiving placebo. Patients recovering from general anesthesia can significantly benefit from modafinil. IMPLICATIONS: Modafinil significantly reduces fatigue and improves feelings of alertness and energy in postoperative patients. Patients recovering from general anesthesia can significantly benefit from modafinil administration.