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Biomedical subjects

J L Lichtor

Publications and source records attributed to J L Lichtor.

At least 19 recordsLinked to original sources
PubMed1992

Subjective and behavioral responses to intravenous fentanyl in healthy volunteers.

Fentanyl is a mu opiate agonist which is occasionally abused by medical personnel who have ready access to the drug. We examined in healthy volunteers (N = 13) the subjective and psychomotor-impairing effects of intravenous fentanyl (0-100 micrograms/70 kg). A randomized, placebo-controlled, crossover design was used in which subjects were injected with 0, 25 (N = 6), 50 and 100 micrograms/70 kg fentanyl in a double-blind fashion. Subjects completed several questionnaires commonly used in abuse liability testing studies before drug injection and at periodic intervals for up to 3 h after drug injection. Subjects also completed several psychomotor tests at these times. Some aspects of psychomotor functioning (e.g., eye-hand coordination) were impaired by fentanyl. Fentanyl produced dose-related increases in ratings of "high" and "sedated," but also tended to produce dysphoria and somatic symptomatology. Most subjects reported liking the effects of the two higher doses of fentanyl for at least a brief time after injection, but they varied widely in their linking ratings across the 3-h post-drug injection period. Despite the transient increases in liking ratings, fentanyl did not increase scores on a widely-used measure of drug-induced euphoria (morphine-benzedrine group scale of the Addiction Research Center Inventory). The present results suggest that some medical personnel who experiment with fentanyl may like it, and thus be at increased risk for abusing the drug in the future.

Adult↗
PubMed1992

Effects of fasting on responses to intravenous fentanyl in healthy volunteers.

The effects of food deprivation on the subjective, psychomotor, and physiological responses to intravenous fentanyl (50 micrograms/70 kg) were studied in 6 healthy male volunteers. A randomized, placebo-controlled, crossover design was used in which subjects were injected with fentanyl or saline after either 2, 12, or 24 hours of fasting. Subjects completed several subjective effects questionnaires as well as psychomotor tasks prior to, and at regular intervals, following the intravenous injection for a 3-hour period. An observer-rated behavioral checklist was completed at regular intervals during the session and several physiological measures (including measurement of pupil size) were recorded. Fentanyl induced opiate-like mood changes, miosis (pupil constriction), and impairment of extraocular muscle control, and 4 of the 6 subjects reported liking the effects; however, fasting had no impact on any of fentanyl's effects. We conclude that food deprivation up to 24 hours does not alter the subjective, psychomotor, or physiological response to the opiate, fentanyl.

Adult↗
PubMed1992

Clinical recovery and psychomotor function after brief anesthesia with propofol or thiopental.

Propofol, the new intravenous anesthetic agent, is generally used in outpatient anesthesia with expectations of fast recovery. We assessed recovery from anesthesia in a double-blind, crossover, controlled manner in 12 healthy volunteers using clinical tests during the first hour and several psychomotor tests 0.5, 1, 3, 5, and 7 h after brief anesthesia with propofol (2.5 mg/kg and 1.0 mg/kg 3 min later) or thiopental (5.0 mg/kg and 2.0 mg/kg 3 min later). Subjects were able to respond to command, sit, and stand steadily significantly faster (P less than 0.05) after propofol (time until standing steadily 33 +/- 7 min; mean +/- SD) when compared to thiopental anesthesia (time until standing steadily 62 +/- 29 min; mean +/- SD). Psychomotor performance remained significantly worse (P less than 0.05 to P less than 0.001) compared to control for 1 h after propofol and for 5 h after thiopental anesthesia. We conclude that the rapid and complete recovery makes propofol a suitable anesthetic for patients undergoing brief ambulatory surgery.

Adult↗
PubMed1992

Subjective and psychomotor effects of subanesthetic doses of propofol in healthy volunteers.

Propofol is increasingly being used in medical and surgical procedures in which conscious sedation of the patient is desired. The mood-altering and psychomotor effects of subanesthetic concentrations of propofol have not been well characterized. Therefore, we examined the effects of intravenous infusions of different subanesthetic doses of propofol on mood and psychomotor/cognitive performance in healthy volunteers (n = 10). A prospective, randomized, placebo-controlled, double-blind, crossover design was used in which subjects first were administered an intravenous loading dose of propofol or placebo (Intralipid) and then were infused over a 20-min period with a given dose of propofol or placebo. Each subject received placebo (Intralipid loading dose and infusion), low-dose propofol (0.08 mg/kg loading dose and 0.5 mg.kg-1.h-1 infusion), moderate-dose propofol (0.16 mg/kg loading dose and 1.0 mg.kg-1.h-1 infusion), and high-dose propofol (0.32 mg/kg loading dose and 2.0 mg.kg-1.h-1 infusion) in four sessions spaced approximately 1 week apart. Propofol induced changes in mood in a dose-related fashion. Some of these mood-altering effects lingered for as long as 30 min after termination of the infusion, but, in general mood had returned to baseline levels 1 h after termination of the infusion. Intralipid induced no changes in mood during the infusion period. Psychomotor functioning was impaired during, and anterograde amnesia was present after, the high-dose propofol infusion. These results suggest that propofol as a sedative has a spectrum of effects that are well-suited for ambulatory surgery (e.g., sedation, amnesia, and rapid and complete recovery).

Adult↗
PubMed1992

Sedation and recovery of psychomotor function after intravenous administration of various doses of midazolam and diazepam.

A placebo-controlled, double-blind, crossover trial in 11 healthy male volunteers compared clinical sedation and psychomotor function after intravenous injection of midazolam (0.05, 0.1, or 0.15 mg/kg), diazepam (0.15 or 0.3 mg/kg), or placebo (saline). The depth of sedation was estimated at 5-10-min intervals during the first hour after injection. A comprehensive battery of psychomotor tests was used to collect objective data of psychomotor performance before drug injection and 1, 3, 5, and 7 h after injection. Midazolam (0.15 mg/kg) produced the highest scores of sedation and most impairment of psychomotor performance. In most tests, the maximal psychomotor effects seen after 0.3 mg/kg of diazepam did not reach those of 0.1 mg/kg of midazolam. Although the strongest psychomotor effects were induced by midazolam, these effects disappeared sooner than those of diazepam. By 5 h after injection, 0.3 mg/kg of diazepam showed the highest scores of psychomotor impairment. The authors conclude that at least four times as much diazepam as midazolam is needed to produce equally severe psychomotor impairment. That the residual effects of midazolam terminate sooner than those of diazepam probably accounts for the occasional underestimation of the potency of midazolam in clinical practice.

Adult↗
PubMed1992

Subjective, behavioral, and physiologic responses to intravenous dezocine in healthy volunteers.

Dezocine is an agonist-antagonist opiate that acts at the mu receptor, and is used for management of pain. Monkeys will readily press a lever to receive an injection of dezocine, and in former opiate addicts dezocine produces positive subjective effects similar to those of morphine. It is not clear, however, what its subjective effects are in people who do not have a history of opiate abuse. To answer this question, a within-subjects design was used in which 10 normal healthy volunteers (six men, four women) were injected with 0, 2.5, 5.0, and 10 mg/70 kg of dezocine in a double-blind fashion. Subjects completed several questionnaires (e.g., Addiction Research Center Inventory) commonly used in abuse liability testing before and at periodic intervals for up to 5 h after drug injection. We also assessed psychomotor performance (e.g., eye-hand coordination) and several physiologic measures (e.g., pupil size, respiration rate) at these times. Dezocine produced increases in ratings of drug liking (P less than 0.001), as well as other subjective effects that might be considered as pleasant ("good mood," "drunken," "coasting," "happy" ratings) (all P less than 0.05). At the same time, the drug had effects (increased dysphoria and sedation) that typically are not reported by addicts. Dezocine produced psychomotor impairment and miosis (constriction of the pupils) in a dose-dependent fashion. The observation that dezocine produces euphoria and increased drug-liking ratings in individuals without histories of drug abuse suggests that hospitals and surgicenters should have strict accountability procedures with this drug.

Adult↗
PubMed1992

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)

Anesthesiology↗
PubMed1991

Alcohol after sedation with i.v. midazolam-fentanyl: effects on psychomotor functioning.

Patients who arrive home several hours after outpatient surgery may drink alcohol. The extent to which residual drugs used in outpatient surgery interact with alcohol is not known. The purpose of this study was to determine if two i.v. drugs commonly used together in outpatient surgery, midazolam and fentanyl, have residual effects which would interact with alcohol drunk 4 h after injection. Twelve healthy male volunteers participated in a double-blind, randomized, placebo-controlled and cross-over study. Subjects were studied four times successively with a period of 1 week between trials. On each day of testing, the subjects received randomly, by slow i.v. injection (30 s), either saline followed immediately by saline, or midazolam 0.1 mg kg-1 followed immediately by fentanyl 2 micrograms kg-1. Four hours after the injection, the subjects consumed a beverage which either did or did not contain alcohol 0.7 g kg-1. Before and 1, 3, 5 and 7 h after injection (and before and 1 and 3 h after consumption of beverage), psychomotor performance and mood were assessed. While both the combination midazolam-fentanyl and alcohol had independent effects on the dependent measures in this study, there was no interaction between midazolam-fentanyl and alcohol (no potentiating of effects of alcohol by i.v. sedation). We conclude that the effects of benzodiazepines and opioids that are short-acting and used in outpatient surgery have probably dissipated by the time a patient arrives home, and that effects from alcohol ingested at home will probably not be affected by recent administration of these drugs.

Adult↗
PubMed1991

Liver transplantation in children from living related donors. Surgical techniques and results.

Pediatric liver transplantation with reduced size donor organs (RLT) has evolved into a standard clinical procedure increasing the choices of recipients for their treatment. Nevertheless organ availability remains a major problem. The authors therefore have proposed to study the use of hepatic segments from living related donors (LRT) in a group of 20 children less than 2 years of age or weighing less than 15 kg, in whom standard indications for transplantation existed. Volunteer related donors were selected after medical and psychiatric evaluations, and the suitability of the donor's liver was established by functional and radiologic criteria. A two-stage informed consent process assured appropriate "volunteerism." Nineteen infants received LRT as first grafts and one as a second graft. Seventeen of the recipients are alive 3 to 18 months after LRT. Fifteen of 20 patients are currently at home with the original graft and normal liver function (bilirubin less than 1.5 mg/dl) after a median hospital stay of 27 days (range, 14-93 days). Four patients underwent retransplantation, in all cases due to arterial thrombosis. The overall graft survival for 20 primary LRTs is 75%, with follow-up between 3 and 18 months. A number of technical problems occurred during our initial trial, the most aggravating being vascular thrombosis. Refined approaches to vascular reconstruction should reduce the incidence of thrombosis and improve the rate of survival in future cases. The donor group for the initial 20 LRT procedures comprised 12 mothers, 7 fathers, and 1 grandmother. In addition one father and one uncle, who was an identical twin of the recipient's father, who did not qualify for anatomic reasons, were used in repeat LRT. All donors survived and are now in normal health between 3 and 18 months after LRT, having returned to all activities enjoyed before donation. The median hospital stay was 6 days (range, 5-14). Complications were minimal, and all were limited to the first three procedures, in which a full left hepatectomy was performed. After alteration of the procedure into a left lateral segmentectomy, no complications were encountered. The left lateral segmentectomy presents minimal surgical trauma to the liver and should remain the primary approach for obtaining a liver graft from a living donor. For children, transplantation of a left lateral segment from a live donor provides a new way of providing a transplant of appropriate size and with good function. The success of this program has led to the acceptance of LRT for general clinical application in the authors' institution.

Adult↗
PubMed1991

Alcohol after midazolam sedation: does it really matter?

Patients who arrive home several hours after ambulatory surgery may drink alcohol. The extent to which the residual effects of drugs used in ambulatory surgery interact with alcohol, perhaps potentiating alcohol effects, is not known. Accordingly, the purpose of this study was to determine whether intravenous midazolam had residual effects that would interact with alcohol consumed 4 h after the midazolam injection. Healthy male volunteers (n = 16) participated in a double-blind, randomized, placebo-controlled crossover trial. Subjects were studied four times successively with 1 wk between trials. On each test day the subjects randomly received by slow intravenous injection (30 s) either saline or 0.1 mg/kg of midazolam. Four hours after injection, the subjects consumed a beverage that either did or did not contain 0.7 g/kg of alcohol. Before and 1, 3, 5, and 7 h after injection (and before and 1 and 3 h after beverage consumption), psychomotor performance and mood were assessed. Whereas both midazolam and alcohol alone had effects on the dependent measures in this study, there were no significant interactions between the two drugs (i.e., potentiation of alcohol effects by midazolam or potentiation of midazolam by alcohol). We conclude that the effects of a short-acting benzodiazepine used in ambulatory surgery have probably dissipated by the time a patient arrives home, and that effects from alcohol ingested at home will probably not be influenced by the recent administration of a short-acting benzodiazepine such as midazolam.

Adult↗
PubMed1991

Ventricular dysfunction does occur during liver transplantation.

Ventricular dysfunction, then, does indeed occur during liver transplantation, particularly at the time of reperfusion. Pulmonary embolism contributes to right ventricular and right atrial encroachment on left-heart filling, and paradoxical embolism may occur. Pericardial effusions, tricuspid regurgitation, hypothermia, and the release of substances, particularly potassium from the donor liver, may further contribute to compromises in ventricular function. Proper monitoring and appropriate treatment, however, lead to successful operative outcomes in most cases.

Heart Arrest↗
PubMed1990

Application of reduced-size liver transplants as split grafts, auxiliary orthotopic grafts, and living related segmental transplants.

The University of Chicago program in pediatric liver transplantation continues actively to seek innovative surgical solutions to problems related to the management of children with end-stage liver disease. Among the most important problems facing these children is a shortage of donor organs, which results from three factors in addition to the actual supply of pediatric donors: the concentration of pediatric liver disease in the population younger than 2 years; the necessity for a graft that is small enough; and the epidemiology of accidents and other events that lead to organ donation. Transplantation using a liver lobe as a graft overcomes size disparity and shifts the available supply of organs from older donors to younger recipients. This work describes the technical aspects of recent innovations in the use of liver lobes in pediatric transplantation, simple reduced-size liver transplantation (RLT), split-liver transplantation (SLT), orthotopic auxiliary liver grafting (ALT), and transplantation using a living related donor (LRLT), and compares their results. Since November 1986 a total of 61 procedures have been performed in which a liver lobe was used as a graft: 26 RLT; 30 SLT, 25 in children and 5 in adults; 5 LRLT; and 1 ALT. Overall 62% of transplants performed in children have involved using a liver lobe as a graft. The rates of complications are somewhat higher than with whole-liver transplantation, but this may not be entirely the result of the complex procedures. Split liver transplantation is associated with the highest mortality and complication rates. Living related liver transplantation has been associated with complications in donors and recipients, but to date survival is 100%. Orthotopic auxiliary liver transplantation effectively corrected the metabolic defect in one patient with ornithine transcarbamylase deficiency. Overall the various modalities of using graft reduction have resulted in postoperative results similar to those achieved with full-size grafts, while pretransplantation mortality has been limited to less than 2%. Thus the use of grafts as liver lobes accomplishes the goal of reducing global mortality among children with end-stage liver disease, but at the cost of increased surgical complexity and more postoperative complications.

Adult↗
PubMed1989

Right heart dysfunction, pulmonary embolism, and paradoxical embolization during liver transplantation. A transesophageal two-dimensional echocardiographic study.

In 16 adult patients, we performed continuous intraoperative two-dimensional transesophageal echocardiography (2DTEE) to help elucidate the mechanism of myocardial dysfunction that accompanies liver transplantation. In 4 of the 16 patients "paradoxical" motion of the interventricular septum consistent with right ventricular failure was seen. An additional three of the 16 patients showed right atrial enlargement and right-to-left deviation of the interatrial septum. Two patients showed evidence of paradoxical embolization (one of whom had right ventricular and right atrial enlargement), and a third patient (who had right atrial enlargement) embolized a large right atrial thrombus into the pulmonary circulation. Two-dimensional transesophageal echocardiography demonstrated that isolated right ventricular failure might account for some of the hemodynamic instability seen during liver transplantation. Venous, pulmonary, and paradoxical embolization of air and thrombi documented by transesophageal echocardiography likely contribute to right heart failure.

Adolescent↗
PubMed1988

Liver transplantation, including the concept of reduced-size liver transplants in children.

Since the establishment of a clinical program in liver transplantation in 1984, 162 liver transplants have been performed in 131 patients (78 adults, 53 children). The patient mortality rate while waiting for a suitable organ has been 8% for adults and only 4% for children (25-46% reported in the literature). The low pediatric mortality is a result of the use of reduced-size liver transplants. A total of 14 procedures have been performed in recipients whose clinical condition was deteriorating and for whom no full-size graft could be located. Of 14 children, 13 were less than 3 years of age. Patient survival is 50%, comparable to survival of high-risk recipients of full-size livers. Using reduced-size liver grafting in a transplant program can lower mortality for children awaiting a transplant by overcoming size disparity. Reduced-size liver grafting will allow more effective use of donor resources and provide a potential avenue of research for organ splitting and living related donation.

Adolescent↗
PubMed1988

Liver transplantation with reduced-size donor organs.

Orthotopic liver transplantation (OLT) of the pediatric patient is often limited by the availability of a size-matched donor organ. Use of reduced liver transplantation (RLT) can increase the proportion of candidates transplanted and may reduce overall mortality. We report herein the initial clinical application of RLT in the United States. Indications for RLT included fulminant hepatic failure (n = 2), acute hepatic artery thrombosis (n = 3), and chronic liver disease unresponsive to inpatient support and more than 30 days on transplant list (n = 4). Donor hepatectomy was performed using standard techniques. Formal hepatic resection was performed ex-vivo to create a size-matched graft, from the larger donor organ, which was implanted in the orthotopic position. Between 11/84 and 4/87, 70 pediatric patients were evaluated for OLT, and 33 of these were transplanted. During this period only 5 patients (7%) died awaiting OLT. Of 33 patients treated at the University of Chicago, 5 received RLT. Donor: recipient weight ratios ranged from 2:1 to 8.1:1. For RLT median operative blood loss was 1.7 blood volumes (range 0.5-11.7) with an operative time of 9.3 + 3.5 hr. Acceptable early graft function was observed in five patients, all of whom were discharged from the hospital. Four of these five patients are alive between 2 and 48 months after transplantation. Marginal graft function with cholestasis and coagulopathy was associated with acute intracranial hemorrhage and neurologic death in one case. One patient died intraoperatively with non-function caused by the use of a liver from a donor with steatosis and a poor size match. Another patient died on day 5 with primary nonfunction and persistent hemorrhage. Systemic cytomegalovirus infection was the cause of death in the other two cases. RLT can provide life-sustaining liver function in urgent clinical settings. The graft can serve as a temporary or permanent liver replacement. With evolution of the technique RLT could eventually be offered to more elective candidates and increase the utilization of available donors by reducing size limitations in OLT.

Adolescent↗