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.

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.

Metabolic substrates other than glucose support axon function in central white matter

We tested the hypothesis that non-glucose energy sources can support axon function in the rat optic nerve. Axon function was assessed by monitoring the stimulus-evoked compound action potential (CAP). CAP was maintained at full amplitude for 2 hr in 10 mM glucose. 20 mM lactate, 20 mM pyruvate, 10 mM fructose, or 10 mM mannose supported axon function as effectively as did glucose, and 10 mM glutamine provided partial support, but beta-hydroxybutyrate, octanoate, sorbitol, alanine, aspartate, and glutamate failed to support axon function. Our results indicated that a variety of compounds can sustain function in CNS myelinated axons. Axons probably use lactate, pyruvate, and glutamine directly as energy substrates, whereas mannose and fructose could be shuttled through astrocytes to lactate, which is then exported to axons.

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.

American Cancer Society guidelines for the early detection of cancer: update of early detection guidelines for prostate, colorectal, and endometrial cancers. Also: update 2001--testing for early lung cancer detection

Updates to the American Cancer Society (ACS) guidelines regarding screening for the early detection of prostate, colorectal, and endometrial cancers, based on the recommendations of recent ACS workshops, are presented. Additionally, the authors review the "cancer-related check-up," clinical encounters that provide case-finding and health counseling opportunities. Finally, the ACS is issuing an updated narrative related to testing for early lung cancer detection for clinicians and individuals at high risk of lung cancer in light of emerging data on new imaging technologies. Although it is likely that current screening protocols will be supplanted in the future by newer, more effective technologies, the establishment of an organized and systematic approach to early cancer detection would lead to greater utilization of existing technology and greater progress in cancer control.

Astrocytic glycogen influences axon function and survival during glucose deprivation in central white matter

We tested the hypothesis that astrocytic glycogen sustains axon function during and enhances axon survival after 60 min of glucose deprivation. Axon function in the rat optic nerve (RON), a CNS white matter tract, was monitored by measuring the area of the stimulus-evoked compound action potential (CAP). Switching to glucose-free artificial CSF (aCSF) had no effect on the CAP area for approximately 30 min, after which the CAP rapidly failed. Exposure to glucose-free aCSF for 60 min caused irreversible injury, which was measured as incomplete recovery of the CAP. Glycogen content of the RON fell to a low stable level 30 min after glucose withdrawal, compatible with rapid use in the absence of glucose. An increase of glycogen content induced by high-glucose pretreatment increased the latency to CAP failure and improved CAP recovery. Conversely, a decrease of glycogen content induced by norepinephrine pretreatment decreased the latency to CAP failure and reduced CAP recovery. To determine whether lactate represented the fuel derived from glycogen and shuttled to axons, we used the lactate transport blockers quercetin, alpha-cyano-4-hydroxycinnamic acid (4-CIN), and p-chloromercuribenzene sulfonic acid (pCMBS). All transport blockers, when applied during glucose withdrawal, decreased latency to CAP failure and decreased CAP recovery. The inhibitors 4-CIN and pCMBS, but not quercetin, blocked lactate uptake by axons. These results indicated that, in the absence of glucose, astrocytic glycogen was broken down to lactate, which was transferred to axons for fuel.

Reversal of rapacuronium block during propofol versus sevoflurane anesthesia

We studied the antagonism of rapacuronium with edrophonium-atropine during propofol- or sevoflurane- based anesthesia in 60 healthy outpatients. After the induction of anesthesia with standardized doses of propofol and fentanyl, rapacuronium 1.5 mg/kg was administered to facilitate tracheal intubation. Patients were randomized to receive either a propofol infusion (100 microg. kg(-1). min(-1)) or sevoflurane (1.0%, end-tidal) in combination with nitrous oxide 66% for maintenance of anesthesia. Neuromuscular block was monitored by using electromyography at the wrist and reversed with edrophonium 1.0 mg/kg and atropine 0.015 mg/kg when the first twitch (T(1)) response of the train-of-four (TOF) stimulation recovered to 25% of the baseline value. The clinical duration of action (i.e., time to 25% T(1) recovery) was similar during both propofol (13.1 +/- 3.6 min) and sevoflu-rane (13.7 +/- 4.4 min) anesthesia. The time from 25% T(1) recovery to TOF ratio of 0.8 was also similar with propofol (3.4 +/- 2.1 min) and sevoflurane (5.9 +/- 8.7 min) (P > 0.05). Although none of the patients in the propofol group required more than 9 min to achieve a TOF ratio of 0. 8, two patients receiving sevoflurane required 31 min and 37 min. Adequate antagonism of rapacuronium block with edrophonium can be achieved within 10 min during propofol anesthesia. However, more prolonged recovery may occur in the presence of sevoflurane.

IMPLICATIONS

We studied the reversal of rapacuronium-induced block with edrophonium and found that the residual rapacuronium block can be readily antagonized during propofol-based anesthesia. However, reversal of rapacuronium appears to be less predictable during sevoflurane-based anesthesia.

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.

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.

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.

An office system for organizing preventive services: a report by the American Cancer Society Advisory Group on Preventive Health Care Reminder Systems

Despite increasing recognition of the importance of preventive services, such services are not provided in primary care practice as often as recommended. One of the most important reasons is the lack of a systematic, organized approach within practices. The American Cancer Society Ad Hoc Advisory Group on Preventive Health Care Reminder Systems reviewed evidence-based reports and expert opinion to summarize current knowledge about office systems for clinical preventive services. This article describes the process of developing an office system for preventive care, beginning with writing a practice policy, auditing charts for baseline performance, developing and implementing a plan for efficient delivery of preventive care, involving office staff, and monitoring progress. Strategies for dissemination of this approach to a wide range of primary care practices may involve professional medical organizations and managed care companies.

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.

Hemodynamic changes during prostatectomy in cardiac patients

Hemodynamic responses to transurethral prostatectomy (TURP) were studied in 9 patients with severe cardiac disease. This group of patients tolerated spinal anesthesia and TURP in an unpredictable manner. One adverse effect was the high pulmonary capillary wedge pressures (WP of 21 mm Hg or higher) in 4 of the 9 patients during operation. All nine cases were considered. Attention was directed toward significant cases. The high WP was not always indicated by high CVP either before or during operation, and it did not necessarily relate to the amount of fluid utilized or amount of prostate resected. Another adverse effect was the marked changes in systemic resistance in 6 patients. Because of the unpredictable hemodynamic responses, thermodilution flow-directed pulmonary artery catheter was valuable in several cases. It made it possible to select specific therapeutic agents and direct tham at isolated hemodynamic dysfunctions.

Morphine and promethazine as intravenous premedicants

Two hundred seventy patients received morphine 5 mg or 10 mg alone or with promethazine 6.25 mg, 12.5 mg, or 25 mg. Promethazine 25 mg alone also was studied. All drugs were given intravenously. Anxiety relief, sedation, patient acceptance, lack of recall, and side effects were the variables examined. Promethazine improved relief of anxiety, sedation, and patient acceptance when added to morphine. Doses of promethazine larger than 12.5 mg intravenously failed to improve these effects. Memory remained unaffected by any of the drugs.