Does small-dose fentanyl improve perioperative outcomes in the ambulatory setting? A randomized, double-blind, placebo-controlled study.

BACKGROUND: Despite its widespread use, the beneficial effect of low-dose fentanyl administered at induction of anesthesia on perioperative outcomes has not been studied in the ambulatory setting. Therefore, this study was designed to test the hypothesis that administration of small-dose fentanyl vs. saline during induction reduces coughing and movements without adversely affecting recovery after day-surgery. METHODS: One hundred consenting outpatients scheduled to undergo superficial surgical procedures under general anesthesia with a laryngeal mask airway (LMA) device for airway management were randomly assigned to one of two treatment groups: control (n = 50) or fentanyl (n = 50). After administration of 2 ml of the unlabelled study medication containing either fentanyl (100 µg) or saline, anesthesia was induced with lidocaine 30-50 mg and propofol 2 mg/kg IV followed by the insertion of an LMA device. General anesthesia was maintained using a propofol infusion, 75 µg/kg/min, and desflurane (2-5% end-tidal) in 100% oxygen. RESULTS: Coughing was observed in six (12%) and ten (20%) in the fentanyl and control group, respectively (P = 0.41). The incidence of movements during surgery was lower in the fentanyl group (18% vs. 31%, P < 0001). There were no significant differences in early and late recovery times or pain scores between the two groups. CONCLUSION: Administration of a small-dose of fentanyl at induction of anesthesia significantly reduced purposeful movements during day-surgery under propofol-desflurane anesthesia. No significant difference was found in coughing or recovery times.

Association of increased postoperative opioid administration with non-small-cell lung cancer recurrence: a retrospective analysis.

BACKGROUND: Evidence suggests that opioid-sparing anaesthetic techniques might be associated with increased cancer-free postoperative survival. This could be related to suppression of natural killer cells by opioid analgesics in the perioperative period. This retrospective analysis tested the hypothesis that greater opioid use in the postoperative period is associated with a higher incidence of recurrences after surgery for lung cancer. METHODS: The medical records of 99 consecutive patients who underwent video-assisted thoracoscopic surgery with lobectomy for Stage I or IIa biopsy-proven non-small-cell lung cancer (NSCLC) were reviewed. Perioperative information including patient characteristics, laboratory data, and surgical, anaesthetic, nursing, and pharmacy reports were collected. Doses of opioids administered intra-operatively and for the first 96 h after operation were converted into equianalgesic doses of oral morphine using a standard conversion table. Data were then compared with the National Cancer Registry's incidence of disease-free survival for 5 yr. RESULTS: A total of 99 patients with similar characteristics were included in the final analysis, 73 of whom were NSCLC recurrence-free at 5 yr and 26 had NSCLC recurrence within 5 yr. Total opioid dose during the 96 h postoperative period was 124 (101) mg of morphine equivalents in the cancer-free group and 232 mg (355) mg in the recurrence group (P=0.02). CONCLUSIONS: This retrospective analysis suggests an association between increased doses of opioids during the initial 96 h postoperative period with a higher recurrence rate of NSCLC within 5 yr.

Ionic mechanisms of aglycemic axon injury in mammalian central white matter.

The authors investigated ionic mechanisms underlying aglycemic axon injury in adult rat optic nerve, a central white matter tract. Axon function was assessed using evoked compound action potentials (CAPs). Glucose withdrawal led to delayed CAP failure, an alkaline extracellular pH shift, and an increase in extracellular [K(+)]. Sixty minutes of glucose withdrawal led to irreversible axon injury. Aglycemic axon injury required extracellular calcium; the extent of injury progressively declined as bath [Ca(2+)] was decreased. To evaluate Ca(2+) movements during aglycemia, the authors recorded extracellular [Ca(2+)] ([Ca(2+)](o)) using Ca(2+)-sensitive microelectrodes. Under control conditions, [Ca(2+)](o) fell with a similar time course to CAP failure, indicating extracellular Ca(2+) moved to an intracellular position during aglycemia. The authors quantified the magnitude of [Ca(2+)]o decrease as the area below baseline [Ca(2+)]o during aglycemia and used this as a qualitative measure of Ca(2+) influx. The authors studied the mechanisms of Ca(2+) influx. Blockade of Na(+) influx reduced Ca(2+) influx and improved CAP recovery, suggesting Na(+)-Ca(2+) exchanger involvement. Consistent with this hypothesis, bepridil reduced axon injury. In addition, diltiazem or nifedipine decreased Ca(2+) influx and increased CAP recovery. The authors conclude aglycemic central white matter injury is caused by Ca(2+) influx into intracellular compartments through reverse Na(+)-Ca(2+) exchange and L-type Ca(2+) channels.

Adenosine-induced release of nitric oxide from cortical astrocytes.

Nitric oxide (NO) and adenosine are involved in coincident CNS functions, including long-term potentiation, neuronal protection, neurotoxicity and cerebral blood flow. We tested the hypothesis that glia may act as a cellular link between the two, through adenosine-induced NO release from astrocytes. A direct NO measuring system was used, allowing the kinetics of NO release to be measured. Our results show that adenosine, acting through purinoceptors, causes NO release from cultured cortical astrocytes. Mobilization of calcium from intracellular stores rather than influx is involved in the adenosine-induced activation of NO synthase. These results demonstrate a possible interaction between adenosine and NO in cerebrovascular physiology and neurotoxicity.

Neurotoxicity in organotypic hippocampal slices mediated by adenosine analogues and nitric oxide.

Adenosine (ADO) and nitric oxide (NO) have been implicated in a variety of neurophysiological actions, including induction of long-term potentiation, regulation of cerebral blood flow, and neurotoxicity/neuroprotection. ADO has been shown to promote NO release from astrocytes by a direct effect on A1 and A2 receptors, thus providing a link between actions of NO and adenosine in the brain. However, while adenosine acts as an endogenous neuroprotectant, NO is believed to be the effector of glutamate neurotoxicity. To resolve this apparent paradox, we have further investigated the effects of adenosine and NO on neuronal viability in cultured organotypic hippocampal slices exposed to sub-lethal (20') in vitro ischemia. Up to a concentration of 500 microM ADO did not cause toxicity while exposures to 100 microM of the stable ADO analogue chloroadenosine (CADO) caused widespread neuronal damage when paired to anoxia/hypoglycemia. CADO effects were significantly prevented by the ADO receptor antagonist theophylline and blockade of NO production by L-NA (100 microM). Moreover, CADO effects were mimicked by the NO donor SIN-1 (100 microM). Application of 100 microM ADO following blockade of adenosine deaminase (with 10 microM EHNA) replicated the effects of CADO. CADO, ADO + EHNA but not ADO alone caused a prolonged and sustained release of nitric oxide as measured by direct amperometric detection. We conclude that at high concentrations and/or following blockade of its enzymatic catabolism, ADO may cause neurotoxicity by triggering NO release from astrocytes. These results demonstrate for the first time that activation of pathways other than those involving neuronal glutamate receptors can trigger NO-mediated neuronal cell death in the hippocampus.

Hemodynamic monitoring of patients undergoing abdominal aortic surgery.

Cardiac decompensation is clearly the major complication of aortic reconstructive surgery that leads to morbidity. Major changes in intravascular volume, third spacing, and increased systemic vascular resistance are extremely stressful to the diseased heart. Hemodynamic monitoring is readily available to provide an accurate evaluation of myocardial sensitivity and to allow for appropriate pharmacologic manipulation to preclude cardiac catastrophe. We believe all patients undergoing abdominal aortic reconstructive surgery should receive the benefit of pulmonary artery catheterization and intraarterial monitoring. The only requirement is a staff of surgeons, anesthesiologists, and nurses capable of correct interpretation of the data and use of drug therapy based on this information. The benefits are an accurate assessment of cardiac function with the ability to modulate the patient's hemodynamic values, preventing volume shifts, hypertensive and hypotensive crises, and abnormal fluctuations in preload and afterload, and ultimately a safer perioperative course.

Defining responsibility for screening.

Patients commonly receive medical care from multiple providers and confusion as to who is responsible for cancer screening undoubtedly contributes to inadequate recommendations. Effective screening requires successful implementation of a series of steps that begin with the initial discussion of a screening test and proceed through obtaining results and instituting appropriate follow-up. Clear definition of generalist and specialist physician roles are necessary to optimally screen the public. This article explores the differences in how generalists and specialists approach screening, describes models of care that facilitate shared responsibility for screening, and suggests strategies on how to improve communication between physicians to maximize screening performance.

Humor in medicine.

The role of humor in medicine is becoming increasingly apparent. Humor helps individuals narrow interpersonal and cultural gaps, communicate difficult messages, express frustration and anger, and cope with anxiety. Primary care providers need to be able to interpret humor used by patients and can learn to use humor to create a healing environment. This article reviews the roles played by humor in the doctor-patient relationship and provides a brief guide to using one's sense of humor to improve and enrich patient care.

Preventive care. Steps toward implementation.

Economic, professional, and consumer forces are pushing prevention to the forefront of health care. Providing preventive care is an effective and valuable service physicians offer patients; however, changing practice styles to routinely incorporate preventive care can be difficult. This article discusses strategies to facilitate the implementation of preventive care in office practice and is based on proven techniques that have helped patients change their undesirable behaviors.

Use of propofol for office-based anesthesia: effect of nitrous oxide on recovery profile.

STUDY OBJECTIVE: To evaluate the effect of nitrous oxide (N2O) on the recovery profile and the incidence of postoperative nausea and vomiting (PONV) after office-based surgery performed under propofol anesthesia. DESIGN: Prospective, randomized, single-blind study. SETTING: Office-based surgical center. PATIENTS: 69 ASA physical status I, II, and III healthy, consenting outpatients undergoing superficial surgical procedures lasting 15 to 45 minutes. INTERVENTIONS: After a standard propofol induction (1.5 mg.kg-1 i.v.), anesthesia was initially maintained with propofol, 100 micrograms.kg-1.min-1 i.v., in combination with either air or N2O 65% in oxygen. The propofol infusion rate was subsequently varied to maintain an adequate depth of anesthesia. All patients received local anesthetic infiltration prior to the surgical incision, as well as during the operation. No prophylactic antiemetics were administered. MEASUREMENTS AND MAIN RESULTS: Recovery times and the incidences of PONV were recorded during the first 24 hours after surgery. Early and late recovery variables were similar in the two treatment groups; however, 65% N2O produced a 19% decrease in the propofol maintenance dosage requirement. One patient (3%) experienced nausea prior to discharge in the propofol-N2O group, and two patients (6%) experienced nausea at home in the propofol alone group. None of the patients vomited or received antiemetic medication during the 24 hours postdischarge period. Ninety-seven percent of patients receiving propofol alone and all of the patients in the propofol-N2O group were "very satisfied" with their anesthetic experience. CONCLUSIONS: In outpatients undergoing office-based surgical procedures with propofol anesthesia, administration of 65% N2O decreased the anesthetic requirement without increasing PONV. Therefore, use of a propofol-N2O combination may be a cost-effective alternative to propofol alone for office-based anesthesia.

Meticulous glucose control in diabetic persons using insulin.

The one advantage a physician has in designing a regimen to control glucose values in a patient with IDDM is that the physiologic mechanism underlying IDDM is homogeneous: All patients are deficient in insulin and tend to be responsive to physiologic amounts of exogenous insulin. Although patients with NIDDM are inherently more stable, the optimal therapy is less clear and physiologic abnormalities must be considered on a case-by-case basis. Maintaining a balance between food intake, exercise, emotions, hormonal changes, and insulin, however, is an ongoing challenge. Only a fraction of IDDM patients are able to achieve excellent control over a long period of time, but it is generally not possible to predict which patients will be able to achieve these goals. Physicians must be patient and persistent in helping patients adhere as closely as possible to a strict diabetic regimen. Psychological, social, and emotional factors must be considered at every visit. Concern over high glucose levels may cause physicians to overlook important emotional events or a family upset that is causing the patient to be less concerned about blood glucose values. If a patient is having trouble adhering to a regimen, the physician should do a complete history and physical examination, with an appropriate differential diagnosis to help address the broad scope of the problem. For most diabetic persons who administer insulin, split, mixed doses given several times throughout the day allow the patient to use a lower total dose and minimize risk of hypoglycemia while improving the potential for glucose control.(ABSTRACT TRUNCATED AT 250 WORDS)

Awake insertion of the fibreoptic intubating LMA CTrach in three morbidly obese patients with potentially difficult airways.

The Intubating Laryngeal Mask Airway (ILMA) is a supraglottic airway that facilitates ventilation and blind tracheal intubation. The LMA CTrach is functionally identical to the ILMA, but has an integrated fibreoptic bundle that provides a view of the larynx. This enables visualisation of tracheal intubation while delivering 100% oxygen, with or without an inhalational anaesthetic. We report awake insertion of the CTrach in three morbidly obese patients (BMI 60-63) with known or anticipated difficult airways. Pre-operatively, patients were given midazolam and glycopyrrolate intravenously, and then in the operating theatre the airway was anaesthetised with topical lidocaine 4%. The CTrach was inserted into the oropharynx of the still-awake patient, the vocal cords were visualised, and anaesthetic induction was commenced with sevoflurane and spontaneous ventilation. Neuromuscular blockers were not used and we were able to see the vocal cords during the entire anaesthetic induction and intubation.