Patient's perceptions of an anesthesia preoperative computerized patient interview

Our desire to elicit a more complete medical history from our patients led to the implementation of a preoperative computerized interview. We previously demonstrated the effectiveness of the interview by computing its mean completion time for the overall patient population (n = 120), and further examined the effects of age, gender, and educational level. In this study, we investigated patient perception of the interview itself. Before and after taking the computer interview, we asked the patients to complete a paper and pencil questionnaire comprised of sixteen questions, expressing their feelings toward the computer interview. Responses elicited prior to taking the computer interview were compared with those obtained afterward. The Stuart-Maxwell test was used to determine statistically significant differences in answers before and after the interview. Initial questionnaire responses reflected a positive attitude toward computer usage which became even stronger after the interview. The only negative responses elicited were really more "doctor positive" than "computer negative." We conclude that patients looked favorably upon participating in a computerized medical interview provided that physician-patient contact is maintained.

Glutamate modulation of dopamine measured in vivo with positron emission tomography (PET) and 11C-raclopride in normal human subjects

Subanesthetic doses of the noncompetitive N-methyl-D-aspartate (NMDA) antagonist ketamine exacerbate psychosis in schizophrenic patients, and ketamine has significant abuse liability. These observations indicate that a secondary effect of ketamine may be to increase dopamine concentrations. The present study was undertaken using positron emission tomography (PET) and the dopamine (D2) radiotracer 11C-raclopride to determine whether ketamine would decrease D2 receptor availability, indicative of an increase in dopamine concentrations. Two scans were performed in seven male control subjects before and after administration of ketamine (0.5 mg/kg, i.v. infused over 20 min). Ketamine significantly increased cortisol levels and decreased dopamine receptor availability in the striatum (specific binding), but not in the cerebellum (nonspecific binding). In addition, the cerebellar binding subtracted from the striatal binding (to account for changes in nonspecific binding) was significantly decreased after ketamine administration. These results provide in vivo evidence for the ability of ketamine to increase striatal dopamine concentrations, consistent with the role of the NMDA receptor in modulating dopamine function.

Serotonergic modulation of dopamine measured with [11C]raclopride and PET in normal human subjects

OBJECTIVE

This study was undertaken to measure serotonergic modulation of dopamine in vivo by using positron emission tomography (PET), a radiotracer for the striatal dopamine D2 receptor ([11C]raclopride), and a pharmacologic challenge of the serotonin system (d,l-fenfluramine).

METHOD

Two PET studies using [11C]raclopride were performed in 11 normal male subjects before administration of the serotonin-releasing agent and reuptake inhibitor fenfluramine (60 mg p.o.) and 3 hours afterward. A graphical analysis method was used with the [11C]raclopride data to derive the distribution volume of D2 receptors. Plasma levels of fenfluramine, norfenfluramine, homovanillic acid (HVA), cortisol, and prolactin were determined.

RESULTS

Levels of fenfluramine and prolactin were elevated 2 hours after fenfluramine administration and remained significantly elevated during the second scan, while levels of HVA and cortisol were not altered significantly during the time of scanning. A significant decrease in the specific binding (striatum) and the nonspecific binding subtracted from the specific binding (striatum minus cerebellum) of [11C]raclopride was observed. The rate of metabolism of [11C]raclopride and the nonspecific binding (cerebellum) were not significantly altered by the fenfluramine intervention.

CONCLUSIONS

The observed decrease in [11C]raclopride binding is consistent with an increase in dopamine concentrations and with the ability of serotonin to stimulate dopamine activity. The ability to measure serotonergic modulation of dopamine in vivo may have implications for the study of etiologic and therapeutic mechanisms in schizophrenia, major depressive disorder, obsessive-compulsive disorder, and substance abuse.

Use of EMLA cream in the treatment of post-herpetic neuralgia

EMLA cream is an acronym for eutectic mixture of local anesthetics. It contains lidocaine and prilocaine creams. A eutectic preparation, applied topically, penetrates into the dermis after an application period of 1 to 2 hours. This case report describes the successful treatment with EMLA cream of post-herpetic neuralgia, which was resistant to other modes of therapy, and briefly discusses the pharmacology of EMLA cream.

Postextubation laryngeal spasm in an unanesthetized patient with Parkinson's disease

We present a patient with Parkinson's disease who experienced laryngeal spasm after tracheal extubation without having been anesthetized. This patient's trachea was intubated because of respiratory arrest. We postulate that her postextubation laryngospasm was related to Parkinson's disease.

Respiratory distress associated with stereotactic irrigation of a brain cyst

Stereotactic neurosurgery is a procedure that usually requires monitored sedation or general anesthesia. The authors report a case in which stereotactic irrigation of a brain cyst was temporally associated with respiratory distress. Additionally, the stereotactic apparatus limits the anesthesiologist's access to the airway.

Large and small airway responses to bronchoconstrictors in the guinea pig and ferret

In the isolated, perfused lung lobe of the ferret we evaluated the bronchoconstrictor response of its airways to methacholine and histamine, pharmacologic agents associated with the asthmatic state. The bronchus of excised lobes was cannulated and needle scarifications were made on the pleural surface to allow perfusate to exit. Lung airways were perfused at constant flow with equilibrated 95% O2/5% CO2, warmed Krebs-Ringers solution. Perfusion pressure was measured as a gauge of airway resistance. A concentration-dependent smooth muscle contraction of the ferret lung lobes was observed to methacholine and histamine. The ED50's of methacholine and histamine were 6.41 x 10(-6) M +/- 1.38 x 10(-6) (SEM) and 6.41 x 10(-6) M +/- 1.38 x 10(-6) (SEM) and 2.39 x 10(-6) M +/- 0.53 x 10(-6) (SEM), respectively. The maximum level of bronchoconstriction developed in the ferret (2.42 mmHg/ml/min +/- 0.28 SEM (resistance units] in response to methacholine, was six times greater than that found for histamine (0.42 mmHg/ml/min +/- 0.05 SEM). Responses to both agonists were less pronounced in the ferret lung preparation than those in a similar lung preparation of guinea pig. Compliance changes in both animals were also evaluated. The ferret did not demonstrate a compliance change in response to histamine as was seen for methacholine, suggesting that resistance changes precede compliance changes, or that the ferret airways are particularly resistant to histamine. Despite a lesser contractile response, the ferret has the advantage of a relatively large lung and long trachea that allow study in several preparations obtained from a single animal. It should prove a useful animal model for study of pulmonary pharmacology.

Anesthetic management of a patient with neuroleptic malignant syndrome

Neuroleptic malignant syndrome is an uncommon, idiosyncratic, and sometimes life-threatening disorder associated with the use of neuroleptic drugs. The pathogenesis of neuroleptic malignant syndrome is uncertain, but it may be similar to that of malignant hyperthermia (MH). Some of the symptoms of neuroleptic malignant syndrome are similar to those of MH. We anesthetized a 17-year-old man with this syndrome multiple times for electroconvulsive therapy (ECT) using a variety of anesthetic techniques. In this patient, dantrolene pretreatment and the use of nondepolarizing muscle relaxants did not relieve symptoms of the syndrome, including fever and creatine phosphokinase (CPK) increases.

Application of the Grieshaber air system to maintain endotracheal tube cuff pressure

The Grieshaber Air System was designed to maintain intraocular pressure during ophthalmologic surgery. It also has been used to maintain pressure in leaking endotracheal tube cuffs. It is a very useful device, especially if the intubation is difficult or the patient's position precludes replacement of the endotracheal tube. Two patients are presented in whom the system was used to maintain endotracheal tube cuff pressure.

Arterial oxygen desaturation in adult dental patients receiving conscious sedation

Forty-six adults undergoing dental procedures were monitored with a pulse oximeter for hypoxemia. Thirty-six patients received various amounts and combinations of central nervous system depressant drugs (barbiturates, sedatives, and narcotics) in addition to local anesthetics to produce a state of conscious sedation. Twenty-eight patients in the latter group received supplemental oxygen. Ten subjects served as a control group and received only local anesthesia without supplemental oxygen. Continuous monitoring by pulse oximetry revealed 151 episodes of mild, 132 of moderate, and 33 of severe arterial oxygen desaturation, although clinical signs of hypoxemia were absent. Patients with a body mass index greater than 30 or those with a smoking history greater than 30 pack-years were particularly prone to arterial oxygen desaturation.

Heinz body hemolytic anemia in newborns and failure of laboratory studies to implicate a phenolic disinfectant

Two unrelated, white, female, premature infants in the same hospital nursery contemporaneously exhibited features of an acute, Heinz body hemolytic anemia: decreased levels of hemoglobin and hematocrit, anisocytosis, fragmented cells, hyperbilirubinemia, reticulocytosis, and red cell inclusion bodies. Physical examination and laboratory studies failed to reveal the etiology of this process. Epidemiologic studies indicated a possible association between the reaction and the improper use and inappropriately high concentration of a phenolic disinfectant. Such an association has been suggested previously between similar products and epidemics of hyperbilirubinemia. Despite extensive experimental efforts (four species, six routes of administration, newborn rats, splenectomized rats, direct incubation with age-matched human cord blood), the reaction could not be produced in the laboratory. It may be highly specific for the intact, human, premature infant. Perhaps the hyperbilirubinemia reported previously had an erythrocytic rather than hepatic origin.