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Biomedical subjects

M F Mulroy

Publications and source records attributed to M F Mulroy.

18 recordsLinked to original sources
PubMed1995

Fentanyl prolongs lidocaine spinal anesthesia without prolonging recovery.

Lidocaine spinal anesthesia is a popular anesthetic for short procedures due to its brief duration. The addition of fentanyl may improve the quality and duration of lidocaine spinal anesthesia. Eight volunteers received plain lidocaine 5% in dextrose (50 mg) both with and without 20 micrograms of fentanyl in a randomized, double-blind, cross-over fashion. Sensory analgesia was assessed with pinprick, cold, touch, transcutaneous electrical stimulation equivalent to surgical incision, and duration of tolerance of pneumatic thigh tourniquet. Motor block was assessed with isometric force dynamometry. Regression of pinprick, touch, and cold was prolonged with fentanyl. Duration of tolerance of electrical stimulation at the umbilicus, hip, knee, and ankle was increased with fentanyl (181% increase from plain lidocaine on average; P < 0.01). Duration of tolerance of tourniquet-induced pain was increased by an average of 48% with addition of fentanyl (P = 0.02). Neither motor block nor time to void was prolonged with fentanyl. Pruritus occurred in all subjects receiving fentanyl but was treated easily and were well tolerated. We recommend the addition of 20 micrograms of fentanyl to lidocaine spinal anesthesia as a means to improve duration of sensory anesthesia without prolonging recovery of motor function or time to micturition.

Adult↗
PubMed1995

Comparison of 5% with dextrose, 1.5% with dextrose, and 1.5% dextrose-free lidocaine solutions for spinal anesthesia in human volunteers.

The use of lidocaine in concentrations less than 5% for spinal anesthesia may be advantageous but has not been carefully studied. Lidocaine 50 mg (1.5% with dextrose and 1.5% dextrose-free) was administered to eight volunteers in a randomized, double blind, cross-over fashion. All of these subjects had previously received 5% lidocaine with dextrose using the same experimental protocol. Sensory analgesia was assessed with pinprick, transcutaneous electrical stimulation (TES) equivalent to surgical incision, and duration of tolerance of pneumatic thigh tourniquet. Motor block was assessed with isometric force dynamometry. Peak dermatomal level was the highest and duration until regression of pinprick the longest with the 5% solution (P < 0.05). Duration of tolerance to TES was increased (33 +/- 10 min) with the 5% solution (P < 0.04). Duration of tolerance to tourniquet pain was increased (11 +/- 3 min) with the 5% solution (P < 0.02). Duration of motor block was increased (45 +/- 9 min) with the 5% and the 1.5% without dextrose solutions (P < 0.04). Time to void was increased (33 +/- 5 min) with the 5% solution (P < 0.03). In conclusion, the use of different solutions of lidocaine for spinal anesthesia results in significant differences in sensory and motor block and time until recovery of micturition.

Adult↗
PubMed1995

Intravenous versus epidural administration of hydromorphone. Effects on analgesia and recovery after radical retropubic prostatectomy.

BACKGROUND: It remains unclear whether epidural administration of hydromorphone results in spinal analgesia or clinical benefit when compared with intravenous administration. Therefore, we undertook this study to determine whether epidural administration of hydromorphone resulted in decreased opioid requirement, improved analgesia, reduced side effects, more rapid return of gastrointestinal function, or shorter duration of hospital stay than intravenous administration. METHODS: Sixteen patients undergoing radical retropubic prostatectomy were randomized in a double-blind manner to receive either intravenous or epidural hydromorphone via patient-controlled analgesia (PCA) for postoperative analgesia. All patients underwent a standardized combined epidural and general anesthetic and all received ketorolac for 72 h postoperatively. To decrease variability, patients were cared for according to a standardized protocol and were deemed ready for discharge according to prospectively defined criteria. RESULTS: Patients in the intravenous PCA group required approximately twice as much opioid than the epidural PCA group (P < 0.008), but there were no differences between groups in pain scores or patient satisfaction. Epidural administration resulted in a greater incidence of pruritus (P = 0.02). Gastrointestinal function recovered quickly in all patients with little variation, and there were no differences between groups. All patients were deemed ready for discharge by the third postoperative day, and removal of surgical drains was the last discharge criterion reached in all patients. CONCLUSIONS: Our results indicate that epidural administration of hydromorphone results in spinally mediated analgesia. However, epidural administration did not provide significant benefits in terms of postoperative analgesia, recovery of gastrointestinal function, or duration of hospitalization. Furthermore, we suggest that radical retropubic prostatectomy no longer be used as a model to assess the effects of analgesic technique on postoperative recovery, because control of discharge criteria revealed that hospital discharge was primarily dependent on removal of surgical drains.

Aged↗
PubMed1994

Regional anesthetic techniques.

Regional anesthesia has several distinct advantages over general anesthesia in the patient scheduled for ambulatory surgery. These include residual analgesia and a lower incidence of postoperative nausea and vomiting. With appropriate choice of regional technique and local anesthetic drug, earlier ambulation and discharge are often possible. These advantages, however, may be negated by the use of excessive sedation. Careful patient selection is required to achieve optimal results. Regional anesthesia requires more time to administer than does general anesthesia, and ideally should be performed in an induction area. However, use of such an area, or employment of techniques with a rapid onset of analgesia (e.g., intravenous regional of spinal anesthesia) may actually reduce the total amount of time a patient spends in the ambulatory unit [16]. Selected application of regional techniques will help convince surgeons, anesthesiologists, and nurses of the advantages of regional blockade and may ultimately lead to greater patient and surgeon satisfaction.

Ambulatory Surgical Procedures↗
PubMed1990

Test doses: optimal epinephrine content with and without acute beta-adrenergic blockade.

The authors studied the optimal epinephrine content of an epidural test dose, and determined criteria to identify intravascular injections in subjects with or without beta-adrenergic blockade. Nine healthy nonpregnant subjects 25-36 years of age were given intravenous infusions of saline or esmolol in random order. During each infusion, they received a series of five injections (3 ml each) of either saline, 1% lidocaine or 1% lidocaine containing 5, 10, or 15 micrograms of epinephrine. Thirty minutes after completing these two infusions, propranolol was administered as a bolus injection, and the series of five injections repeated. All injections were double blind and randomized. During saline infusion, all injections containing epinephrine significantly increased heart rate (HR) by an average of 31-38 beats/min when compared with that following plain lidocaine (P less than 0.05), and increased systolic blood pressure by an average of 17-26 mmHg (P less than 0.05 for the 15-micrograms dose only). During esmolol infusion, epinephrine injections increased HR by an average of 23-31 beats/min (P less than 0.05), and increased systolic blood pressure by an average of 18-30 mmHg (P less than 0.05 for 10 and 15 micrograms). After propranolol injection, epinephrine injections caused a decrease in HR by an average of 21-28 beats/min (P less than 0.05), whereas systolic blood pressure increased by an average of 22-35 mmHg (P less than 0.05 for 10 and 15 micrograms only). Without beta-adrenergic blockade, an increase in HR greater than or equal to 20 beats/min was 100% sensitive and specific for intravascular injection of 10 or 15 micrograms of epinephrine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1986

Edrophonium antagonizes combined lidocaine-pancuronium and verapamil-pancuronium neuromuscular blockade in cats.

The effects of lidocaine or verapamil on pancuronium neuromuscular blockade and the ability of anticholinesterase agents to antagonize these combined blockades were studied in 14 cats using a standard peroneal nerve-anterior tibialis muscle preparation. Pancuronium was infused at a constant rate to produce a stable 50% depression of single twitch tension. In nine cats, intravenous lidocaine boluses followed by a constant infusion produced serum lidocaine levels of 5.09 +/- 1.9 micrograms/ml (mean +/- SD) and resulted in an additional 20.0 +/- 5.5% depression of twitch tension. In the other five cats, intravenous injection of 0.15 mg/kg of verapamil produced an additional 12.8 +/- 8.0% twitch depression of pancuronium-induced neuromuscular blockade. For individual animals, edrophonium antagonism of the combined lidocaine-pancuronium-induced neuromuscular blockade or combined verapamil-pancuronium-induced neuromuscular blockade was not significantly different from antagonism of an equivalent twitch depression produced by pancuronium alone. It is concluded that lidocaine and verapamil augment neuromuscular blockade caused by pancuronium and that anticholinesterase antagonism of this augmented blockade can be expected to occur in a normal fashion.

Animals↗
PubMed1984

Outpatient inguinal herniorrhaphy with both regional and local anesthesia.

Fifty-three patients who were undergoing outpatient inguinal herniorrhaphy with short-acting regional anesthetic agents and local infiltration of a long-acting anesthetic were retrospectively compared with a matched population of 53 hospitalized patients who were undergoing herniorrhaphy with a long-acting regional anesthetic. There was a significantly greater incidence of urinary retention in the hospitalized patients who received long-acting regional anesthetic agents. Otherwise, complications in the two groups were similar. Inguinal herniorrhaphy can be accomplished as an outpatient procedure without increased morbidity. This can result in significant savings in hospital bills. We suggest that anesthesia for inguinal herniorrhaphy is most satisfactorily provided by the combination of a short-acting regional anesthetic agent and a long-acting local one.

Adolescent↗
PubMed1981

Performance evaluation: continuous lumbar epidural anesthesia skill test.

The evaluation of skills in anesthesiology residents is usually subjective and lacks demonstrable reliability. Therefore, an objective criterion-referenced skill test for measuring performance of continuous lumbar epidural anesthesia was developed. For such a test to be useful, it is necessary to demonstrate agreement among rater-observers. Eight performances of continuous lumbar epidural anesthesia were recorded on video tape and simultaneously rated by nine anesthesiology faculty observers to determine inter-rater reliability. Inter-rater agreement was analyzed by determining coefficient kappa for each item and the entire test. Coefficient kappa for the entire test was 0.82 indicating a high degree of agreement between raters on the performance or nonperformance of various items. Development and utility of skill tests are discussed.

Anesthesia, Epidural↗
PubMedDate not supplied

Age, chronic obstructive pulmonary disease, and Innovar induced ventilatory depression during regional anesthesia.

The effect of Innovar on ventilatory response to CO2 was studied in 35 patients undergoing peripheral surgery with regional anesthesia. The dosage schedule (per 70 kg body weight) was 2 ml intramuscularly, prior to the block, and 1 ml intravenously, after the block. The decrease in mean CO2 response slope (15 percent decrease from control 30 minutes after the first dose) was not statistically significant. Control slope varied inversely with age (r = 0.41, p less than 0.05), and (in 22 patients) directly with the FEV1/FVC ratio (r = 0.54, p less than 0.02) and with the combined variables (FEV1/FVC)/age (r = 0.58, p less than 0.01). Depression of CO2 response slope following Innovar did not vary with age or FEV1. We conclude that, in otherwise normal patients, these doses of innovar cause only minor depression of ventilatory response to CO2. However, in those patients who already have a depressed response (the elderly and those with a decreased FEV1/FVC ratio), this additional depression occasionally may be clinically important.

Adolescent↗
PubMedDate not supplied

The reliability of epidural anesthesia for repeat ESWL: a study of changes in epidural compliance.

Changes in epidural compliance were investigated before and after extracorporeal shock wave lithotripsy (ESWL) in 11 outpatients. Epidural pressures were unchanged acutely by ESWL (p greater than 0.15). In contrast to previous reports of failures of epidural anesthesia in patients having repeat ESWL treatments, a review of our population of patients having repeat ESWL indicates that epidural anesthesia is reliable and not associated with any greater failure rate than for initial ESWL treatments. The difference between our results and previous reports of high failure rates is likely due to differences in anesthetic and surgical techniques such as: (1) use of air for loss-of-resistance when locating the epidural space, (2) differences in the time interval between ESWL treatments, and (3) frequency of use of epidural catheters.

Anesthesia, Epidural↗
PubMedDate not supplied

Chloroprocaine and lidocaine decrease hospital stay and admission rate after outpatient epidural anesthesia.

Lumbar epidural anesthesia with 20 ml of either 3% 2-chloroprocaine (C), 1.5% lidocaine (L), or 1.5% mepivacaine (M) with epinephrine was studied in 84 outpatients undergoing surgery (extracorporeal shock wave lithotripsy (ESWL]. The average duration of the procedure was 31.9 minutes. The total duration of sensory anesthesia was 133 +/- 28 minutes (C), 182 +/- 38 (L), and 247 +/- 42 (M) (p less than 0.05). Times to discharge were 269 +/- 62 minutes (C), 284 +/- 62 (L), and 357 +/- 71 (M). The time to discharge with M, almost six hours, was significantly longer than with C or L. There was a trend to an increasing rate of unplanned overnight hospital admission with increasing duration of the local anesthetic drug employed. Continuous epidural anesthesia with C, L or M appears safe and effective for outpatient surgical procedures such as ESWL. In contrast to previous understanding, mepivacaine produces significantly longer anesthesia and recovery times and may not be optimal for outpatient epidural use.

Adult↗
PubMedDate not supplied

Aging reduces the reliability of epidural epinephrine test doses.

BACKGROUND AND OBJECTIVES: The authors recently determined that intravascular injection of an epinephrine test dose reliably produced an increase in heart rate > or = 20 beats/min in young individuals. However, aging is associated with a significant reduction in beta-adrenergic responsiveness. This study was designed to determine whether aging decreases the magnitude of heart rate (HR) increase after intravascular injection of epinephrine. METHODS: Heart rate and systolic blood pressure were recorded during randomized and double-blind injections of 3 mL lidocaine plain or lidocaine with 10 or 15 micrograms epinephrine in 30 elective surgical patients between 21 and 81 years old. RESULTS: Increasing age was associated with smaller increases in HR after intravascular injection of epinephrine. The reduction in HR increase was statistically significant after 10 micrograms (P = .006, r2 = .24), but not after 15 micrograms (P = .25, r2 = .05) of epinephrine. Heart rate increases were of greater magnitude for patients younger than 40 years old (P = .01 for 10 micrograms epinephrine, and P = .03 for 15 micrograms epinephrine). One patient (of 11) over 60 did not respond to the 15 micrograms test dose with tachycardia. Aging did not alter systolic blood pressure increases after 10 or 15 micrograms epinephrine (P = .27, r2 = .04 and P = .4, r2 = .03, respectively). CONCLUSIONS: Aging is associated with a reduction in the magnitude of HR increase after intravenous injection of epinephrine. The results suggest that to detect an intravascular injection in healthy people, a test dose containing 10 micrograms epinephrine will suffice before the age of 40. However, even 15 micrograms epinephrine will not be totally reliable in older patients, owing to decreased beta-adrenergic responsiveness.

Adult↗