Volume 91, Issue 12

A retrospective study investigated features common to 85 documented cases of spinal-anesthesia-induced hypotension. Low preoperative systolic blood pressure and anemia were the most predictive features. Physical status was less important, with the exception of emergency surgeries. An association was found between preoperative medication--especially narcotics-and hypotension. Other variables found to have a high frequency among hypotensive patients were known preexisting pathologic conditions, increasing concentrations of anesthetic used at the time of surgery, and increasing levels of anesthesia achieved. The study is weighted toward obstetric/gynecologic cases.

Fifteen patients undergoing total hip and total knee replacement were studied prospectively to evaluate postoperative pain relief provided by an epidural infusion of fentanyl citrate, with and without lidocaine hydrochloride, and changes in arterial flow to the lower extremities. The patients were randomly placed in three groups: group 1 received epidural fentanyl, 5 j.Lg/mL; group 2 received epidural fentanyl, 5 j.Lg/mL with 0.75% solution of lidocaine; and group 3 received epidural fentanyl, 5 j.Lg/mL with 1.0% solution of lidocaine. All patients received 1.5% solution of epidural etidocaine hydrochloride with epinephrine 1:200,000 for intraoperative anesthesia. No clinical evidence of deep vein thrombosis, tachyphylactic reaction to lidocaine, orthostatic hypotension, or motor block was demonstrated in any patient. The addition of lidocaine to the epidural fentanyl infusion did not improve pain relief or allow a decrease in the rate of infusion. Patients in all groups had improved arterial flow to the lower extremities 24 hours postoperatively.

The ordering, reviewing, and interpreting of laboratory tests require recognition and familiarity with the concepts of normal values, sensitivity, specificity, predictive values, and prevalence. The significance of these test properties in clinical decision-making is explained.