A comparison of intraarticular morphine and bupivacaine for pain control after outpatient knee arthroscopy. A prospective, randomized, double-blinded study.

To determine the duration of pain relief and efficacy of intraarticular morphine compared with bupivacaine after outpatient knee arthroscopy under local anesthesia, we gave patients one of three postoperative intraarticular injections: 4 mg morphine, 0.25% bupivacaine, or 0.9% saline. Visual analog scale scores and supplemental pain medication use were recorded at 0 to 30 minutes, 2, 4, 6, 8 to 12, and 24 hours after surgery. The score on the visual analog scale at 24 hours was significantly lower in the morphine group than in the bupivacaine or control groups. The cumulative amount of pain medication used was significantly lower in the morphine and bupivacaine groups at 2 to 6 hours after surgery than in the saline control group. The morphine group used the least supplemental pain medication during the 12 to 24 hour interval (P = 0.06). We found that the use of intraarticular morphine or bupivacaine after outpatient knee arthroscopy will decrease the amount of narcotic medication needed for pain relief during the early postoperative period. In addition, morphine provided prolonged pain relief up to 24 hours when compared with bupivacaine or placebo, and the patients in the morphine group tended to take less supplemental pain medication during the first postoperative day.

Effects of subcutaneous verapamil on the duration of local anesthetic blockade.

STUDY OBJECTIVES: To determine whether a subcutaneous injection of verapamil will provide local anesthesia and whether a mixture of lidocaine and verapamil will prolong the anesthetic effect of lidocaine alone. DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Preanesthetic area of a large metropolitan teaching hospital. PATIENTS: 20 volunteers. INTERVENTIONS: All volunteers received 4 injections of normal saline, verapamil, lidocaine, and lidocaine-verapamil at the volar aspect of the forearm. The sites were tested with a 26-gauge needle to be sure the sensation of sharp could be appreciated. The injections were performed in a randomized, double-blind fashion using a sterile technique. The 4 areas were tested at 1-minute intervals using a 26-gauge needle until the sensation of sharp was again perceived. MEASUREMENTS AND MAIN RESULTS: Injection sites were examined for the presence and degree of erythema. Volunteers were asked to rate the degree of pain felt during and immediately after injection. The time elapsed until the person was again able to perceive sharp from a 26-gauge needle prick was measured at all 4 sites. When compared with the effects of normal saline, subcutaneous verapamil provided local anesthesia to pinprick. The mixture of verapamil and lidocaine also provided anesthesia to pinprick, but the duration of effect was less than that provided by lidocaine alone. The use of verapamil alone and in combination with lidocaine was associated with a marked degree of erythema and edema. CONCLUSIONS: Verapamil injected subcutaneously provides a degree of local anesthesia. However, this effect is hampered by a local reaction at the injection site and a short duration of action. The mixture of lidocaine and verapamil provides a shorter duration of action than does lidocaine alone.

Risk of human immunodeficiency virus in surgeons, anesthesiologists, and medical students.

We postulated that three factors determined the occupational risk of infection from the human immunodeficiency virus (HIV) for surgeons, anesthesiologists, and medical students: first, the risk of needlestick exposure per year (range for surgeons 3.8-6.2, weighted average 4.2; range for anesthesiologists 0.86-2.5, weighted average 1.3; range for third-year medical students 0-5, best estimate 5); second, the risk of seroconversion from a needlestick exposure (0.42%-0.50%); and third, prevalence of HIV in the population served (0.32%-23.6%, depending on geographic location). Thus, the calculated range for occupational risk of HIV infection for a surgeon over a 30-yr period (assuming no change in HIV prevalence or benefit from protective measures) was 0.17%-13.9%; for an anesthesiologist, 0.05%-4.50%. The corresponding range of occupational risk for a medical student during the third year was 0.007%-0.59%. The range of risk is large because the variation in prevalence of HIV infection from one area to another is great. The authors validated the methodology first by using an equation, with estimates from the literature for factors in the equation, to calculate the risk of infection for hepatitis B and then by comparing the results with known rates of infection in the prevaccine era. Calculated occupational risk of hepatitis B infection for anesthesiologists was in the lower range of actual prevalence of infection (calculated range 2.32%-20.6%; known range 6%-26%). Calculated risk versus prevalence for surgeons was fairly close (7.31%-53.4% versus 24.4%).(ABSTRACT TRUNCATED AT 250 WORDS)

Low-frequency magnetic field technology: quantifying spinal range of motion.

Reliability of a sensitive, noninvasive technique for quantifying spinal range of motion was assessed by investigators who measured lumbar mobility of 19 subjects with no history of low-back pain or spinal abnormalities. The measurement method used low-frequency, quasistatic magnetic dipole field and sensors which disturb this field in a precisely quantifiable manner. Sensors, affixed to the skin over T12 to L1 interspace and over the sacrum at the level of S1, were directly interfaced with an IBM PC-AT microcomputer, which was used for error-free collection and storage of data. Measurement results compared favorably to those obtained from the biplanar radiographic technique. Statistical analysis showed an extremely high degree of intraobserver and interobserver reliability. Additional advantages included simplicity and noninvasiveness. Overall, the magnetic field technique proved a significant advancement in clinically quantifying spinal mobility, allowing precise determination of impairment under American Medical Association guidelines.

Myopia and intelligence: a pleiotropic relationship?

The well-established association between myopia and superior intelligence in the general population was investigated in a group of intellectually gifted children and their less gifted full siblings to determine whether the relationship of myopia to psychometric intelligence is consistent with the hypothesis of pleiotropy, i.e., both characteristics are affected by the same gene or set of genes. Failure to find a difference in degree of myopia, assessed as a metric variable, between intellectually gifted and nongifted siblings would contradict pleiotropy. A variety of possible causal pathways, both genetic and environmental, have been hypothesized in the literature to explain the relationship between intelligence and myopia, and these still cannot be ruled out. It is theoretically noteworthy, however, in view of the independent evidence for the considerable heritability of both intelligence and myopia, that the highly significant gifted-nongifted sibling difference in myopia found in the present study is consistent with the hypothesis that intelligence and myopia are related pleiotropically.