Effect of propofol for induction and ondansetron with or without dexamethasone for the prevention of nausea and vomiting after major gynecologic surgery

STUDY OBJECTIVES

To test the hypothesis that for major gynecologic surgery the combination of propofol for induction, ondansetron, and dexamethasone would be a more effective antiemetic combination than propofol for induction, ondansetron, and saline; and to determine if a propofol induction of anesthesia improved our previously reported results when thiamylal was the induction drug.

DESIGN

Double-blind, randomized study.

SETTING

Magee-Womens Hospital, Pittsburgh, Pennsylvania.

PATIENTS

80 healthy ASA physical status I, II, and III female inpatients scheduled for major gynecologic surgery.

INTERVENTIONS

After induction of anesthesia with propofol, Group 1 received intravenous (IV) ondansetron 4 mg and saline, and Group 2 received IV ondansetron 4 mg followed by IV dexamethasone 20 mg.

MEASUREMENTS AND MAIN RESULTS

For Group 1 and Group 2, respectively, no emesis and no rescue occurred in 15 (37.5%) and 21 (52.5%) patients (p = 0.13); emesis occurred in 7 (17.5%) Group 1 patients and 5 (12.5%) Group 2 patients, rescue antiemetic 23 (57.5%) Group 1 patients and 19 (47.5%) Group 2 patients. Nausea was reported by 31 (77.5%) Group 1 patients and 30 (75%) Group 2 patients.

CONCLUSIONS

The hypothesis that the addition of dexamethasone to the propofolondansetron combination would significantly reduce postoperative nausea and vomiting (PONV) was not confirmed. A propofol induction of anesthesia resulted in a comparable incidence of PONV when compared with our previously reported results using thiamylal for induction of anesthesia for women having major gynecologic operations.

Droperidol/ondansetron combination controls nausea and vomiting after tubal banding

The antiemetic activity of droperidol is attributed to antagonizing the dopaminergic neurons of the chemoreceptor trigger zone. Ondansetron is a serotonin (5HT) receptor antagonist at both peripheral and central 5-HT3 receptor sites with no known action on dopamine-mediated activity. We hypothesized that the combination of these two antiemetics would be more effective than droperidol alone. Women with ASA classified physical status I or II, scheduled for laparoscopic tubal banding, participated in a randomized double-blind clinical trial using a standardized anesthesia regimen. Within 15 min after induction of anesthesia, Group 1 (n = 60) received IV droperidol 1.25 mg and ondansetron 4 mg and Group 2 (n = 60) received IV droperidol 1.25 mg and saline. Before surgery and during recovery at 1, 2, and 24 h, emetic episodes, nausea, pain, drowsiness, medications taken, and adverse events were recorded. The complete response (no emesis, no rescue) for Group 1 was 55 of 60 (91.6%) versus 47 of 60 (78.3%) in Group 2 (P = 0.04). No patient needed rescue antiemetic medication in Group 1, whereas 5 of 60 (8.3%) patients were rescued in Group 2 (P = 0.03). There were seven emetic episodes in five patients in Group 1 and 30 emetic episodes in 12 patients in Group 2 over the 24-h study period (P = 0.03). The time to the first emetic episode was more than twice as long for Group 1 than Group 2 (P = 0.03) and total nausea scores were lower in Group 1 than Group 2 (P = 0.01). The droperidol/ondansetron combination was significantly superior to droperidol in complete response, time to and number of emetic episodes, and the incidence and severity of nausea in women having tubal banding.

Resolving the apparent discrepancy between the incongruency effect and the expectancy-based illusory correlation effect: the TRAP model

The incongruency effect and the expectancy-based illusory correlation effect seem contradictory because they describe apparently contrasting consequences of previously held expectancies: better recall of incongruent than congruent items but overestimation of congruent items. This article resolves this dilemma by presenting a model that is able to simultaneously predict both of these effects. The Twofold Retrieval by Associative Pathways (TRAP) model adopts the encoding assumptions of person memory models but distinguishes between two different retrieval processes, exhaustive and heuristic, hypothesized to underlie recall and frequency estimation, respectively. Experiment 1 showed that expectancy-based illusory correlation effects and incongruency effects are compatible in that they were produced simultaneously. Experiments 2 and 3 tested and rejected alternative explanations for the obtained pattern of results.

Perceiving persons and groups

This article analyzes the similarities and differences in forming impressions of individuals and in developing conceptions of groups. In both cases, the perceiver develops a mental conception of the target (individual or group) on the basis of available information and uses that information to make judgments about that person or group. However, a review of existing evidence reveals differences in the outcomes of impressions formed of individual and group targets, even when those impressions are based on the very same behavioral information. A model is proposed to account for these differences. The model emphasizes the role of differing expectancies of unity and coherence in individual and group targets, which in turn engage different mechanisms for processing information and making judgments. Implications of the model are discussed.

Illusory correlation in the perception of groups: an extension of the distinctiveness-based account

The prevailing explanation for illusory correlation in the stereotyping of groups is that distinctive information (minority groups' infrequent behaviors) is salient, receives enhanced encoding, and becomes highly accessible, thus biasing subsequent judgments. This distinctiveness-based explanation (DBE) depends on information distinctiveness at the time of its encoding. Information distinctiveness at encoding was manipulated, while ultimate distinctiveness was kept constant. Experiment 1, contrary to the DBE, found illusory correlations emerge regardless of distinctiveness at encoding. Experiment 2 collected process data that showed that ultimately distinctive behaviors were highly accessible at the time of judgment even when they were not distinctive at encoding. Experiments 3-5 ruled out an alternative account. A basis for illusory correlation that depends on postpresentation, but prejudgment, encoding of distinctive information is suggested.

Illusory correlation in the perception of groups: an extension of the distinctiveness-based account

The prevailing explanation for illusory correlation in the stereotyping of groups is that distinctive information (minority groups' infrequent behaviors) is salient, receives enhanced encoding, and becomes highly accessible, thus biasing subsequent judgments. This distinctiveness-based explanation (DBE) depends on information distinctiveness at the time of its encoding. Information distinctiveness at encoding was manipulated, while ultimate distinctiveness was kept constant. Experiment 1, contrary to the DBE, found illusory correlations emerge regardless of distinctiveness at encoding. Experiment 2 collected process data that showed that ultimately distinctive behaviors were highly accessible at the time of judgment even when they were not distinctive at encoding. Experiments 3-5 ruled out an alternative account. A basis for illusory correlation that depends on postpresentation, but prejudgment, encoding of distinctive information is suggested.

On-line and memory-based aspects of individual and group target judgments

Ss were given instruction sets to induce either on-line or memory-based processing while reading behavioral statements about individual and group targets. Impression-set instructions induced online judgments, and comprehensibility-set (comp) instructions induced memory-based judgments regardless of target type. More important, with nondirective instructions (memory set), natural differences in processing information about individuals and groups were observed, with more online judgments for individuals. As expected, illusory correlations between minority targets and infrequent behaviors (a memory-based product) emerged with comp instructions (which induced memory-based judgments for both target types) and in the memory-set condition for group targets only. These data provide insights into the differences in impression formation for groups and individuals and furnish direct evidence of the processes responsible for illusory correlations.

Self-stereotyping and social context: the effects of relative in-group size and in-group status

In 2 laboratory experiments, the tendency to stereotype oneself in terms of one's group membership as a function of the social context was examined. Experiment 1 examined the effects of relative in-group size on self-stereotyping. The results confirmed the prediction that minority members are more likely than majority members to stereotype themselves. Experiment 2 examined the interactive impact of relative in-group size and in-group status. As predicted, a high (relative to a low) status of the in-group increased self-stereotyping primarily for minority members, but not for majority members. Moreover, analyses of the differences in perceived in-group and out-group homogeneity suggest that the in-group homogeneity effect should also be interpreted in terms of self-stereotyping processes. Finally, the interplay between cognitive and motivational determinants of self-stereotyping is discussed as well as a possible distinction between self-stereotyping effects on individual level versus group level self-representations.

Self-stereotyping and social context: the effects of relative in-group size and in-group status

In 2 laboratory experiments, the tendency to stereotype oneself in terms of one's group membership as a function of the social context was examined. Experiment 1 examined the effects of relative in-group size on self-stereotyping. The results confirmed the prediction that minority members are more likely than majority members to stereotype themselves. Experiment 2 examined the interactive impact of relative in-group size and in-group status. As predicted, a high (relative to a low) status of the in-group increased self-stereotyping primarily for minority members, but not for majority members. Moreover, analyses of the differences in perceived in-group and out-group homogeneity suggest that the in-group homogeneity effect should also be interpreted in terms of self-stereotyping processes. Finally, the interplay between cognitive and motivational determinants of self-stereotyping is discussed as well as a possible distinction between self-stereotyping effects on individual level versus group level self-representations.

The effect of the submandibular salivary gland on the erythropoietin response to hypoxia in mice with chronic renal failure

The role of the submandibular salivary gland (SG) in the renal and extrarenal erythropoietin (Epo) response to hypoxia was evaluated in adult male mice with chronic renal failure from partial nephrectomy. A partial nephrectomy model for chronic renal failure was used in an attempt to evaluate erythropoiesis and Epo production in mice whose renal source of Epo may be compromised and thus more dependent on extrarenal sources. Mice with two-thirds of total renal mass excised developed a three-fold increase in serum creatinine concentration, polyuria, and polydipsia but not anemia. They responded to the combined challenge of hypobaric hypoxia (17 hours, 0.5 atm) and anemia from phenylhydrazine treatment (60 mg/kg intraperitoneally [i.p.]) with a consistent increase in serum Epo. This response was not affected by either acute or chronic bilateral submandibularectomy. However, bilateral submandibularectomy in mice with chronic renal failure was associated with a reduction in serum creatinine (p < 0.01). The possibility that reduction of renal mass might increase extrarenal secretion of Epo was examined in mice with chronic renal failure by removing the kidney remnant and exposing them to a severe hypoxic challenge. While acute bilateral submandibularectomy did not influence the extrarenal Epo response to severe hypoxia, mice with partial nephrectomies had a greater Epo response to hypoxia than control mice with a recent bilateral nephrectomy. In conclusion, the submandibular salivary glands do not appear to be an extrarenal source of Epo, nor do they appear to contribute to the enhanced extrarenal Epo response of mice with chronic renal failure.

The effect of bilateral removal of the submandibulary salivary glands on the erythropoietic response of mice

The role of the submandibular salivary gland in erythropoiesis in the male mouse (MRC TO strain) was evaluated by subjecting mice without submandibular salivary glands (SX) and control (C) sham-operated mice to a variety of stimuli intended to stress the erythropoietic system. In SX mice, after removal of the submandibular glands at age 4 weeks and observation for 8 weeks, mean hematocrit was the same as in C mice, but mean body weight was less. Bilateral removal of the submandibular glands at age 6 weeks neither affected the rate of fall and subsequent recovery of hematocrit which followed treatment with phenylhydrazine (80 mg/kg intraperitoneally [i.p.] 9 days after operation) nor altered the rate of increase in hematocrit or change in body weight which occurred during hypobaric hypoxia (0.5 atm, > 23 hours/day) for 23 days. Mean (SEM) estimates of serum immunoreactive erythropoietin after 17 hours' continuous hypobaric (0.5 atm) exposure were not significantly different between SX [186 (30) mU/mL, n = 7] and C mice [232 (17) mU/mL, n = 7]. In mice given bilateral nephrectomies at age 6 weeks--2 weeks after SX or C surgery--and then both treated with phenylhydrazine (60 mg/kg i.p.) and exposed for 17 hours to hypobaric (0.5 atm) hypoxia, mean estimates of serum immunoreactive erythropoietin were 22.6 (10.6) mU/mL and 22.3 (5.4) mU/mL in SX (n = 5) and C (n = 5) mice. Results of the study do not support the premise that the submandibular salivary glands either contribute to the erythropoietic response or are a source of extrarenal erythropoietin.

Use of breath hydrogen measurement to evaluate orocecal transit time in cats before and after treatment for hyperthyroidism

Orocecal transit time was evaluated in 13 cats diagnosed with hyperthyroidism. Transit was determined by measuring the change in breath hydrogen and methane concentrations following oral administration of a nonabsorbable carbohydrate (lactulose). Transit times before and three to four weeks after treatment of the hyperthyroidism with radioactive iodine were compared. There was a significant prolongation of transit time, as determined by a change in hydrogen concentration, following correction of the hyperthyroidism (p = 0.034). Average transit times and standard errors were 27.7 +/- 3.7 minutes before treatment and 56.5 +/- 12.1 minutes after treatment. Methane was not detected in any of the samples. Hyperthyroidism appears to be associated with an accelerated small intestinal transit time in cats.

The effects of thiamin on lead metabolism: organ distribution of lead 203

The effect of thiamin on the organ distribution of lead was evaluated in CD-1 mice exposed intragastrically or intraperitoneally to a single dose of lead acetate (100 micrograms) containing 100 microCi lead 203. They were treated with either thiamin (25 or 50 mg/kg body weight), calcium ethylenediaminetetraacetic acid (CaEDTA) (50 mg/kg body weight), or combinations of thiamin and CaEDTA. The whole body retention and the organ distribution of lead 203 varied depending upon the route of lead administration, dose of thiamin and the specific treatment combination. Thiamin (25 or 50 mg/kg) treatment increased the whole body retention of both intragastric and intraperitoneal lead by approximately 10% in each instance. Calcium ethylenediaminetetraacetic acid, either alone or in combination with thiamin (50 mg/kg) reduced the whole body retention of lead by as much as 14% regardless of route of lead exposure. The relative retention of lead by the liver, kidney and spleen was greater in mice exposed to lead by the intragastric route. Regardless of route, CaEDTA in the combined treatment reduced the relative retention of lead in both the liver and kidney, whereas thiamin alone only reduced the retention of lead in the kidney. The results of this study indicate that thiamin in combination with CaEDTA alters the distribution and retention of lead in a manner which may have therapeutic application as it relates to chelation therapy.

Affect and stereotyping: the effect of induced mood on distinctiveness-based illusory correlations

In 2 studies, the effects of mood on the formation of distinctiveness-based illusory correlations were examined. After exposure to stimuli inducing positive, neutral, or negative mood, Ss read information about behaviors performed by members of 2 groups in an illusory correlation paradigm. In both experiments, only Ss in a neutral mood formed illusory correlations. In addition, Experiment 2 assessed Ss' processing latencies as a means of investigating differential attention to distinctive behaviors. Only Ss in a neutral mood differentially attended to the minority group's infrequent behaviors. Induced mood apparently interfered with the processing necessary to differentially encode distinctive stimuli, undermining the illusory correlation effect.

Affect and stereotyping: The effect of induced mood on distinctiveness-based illusory correlations

In 2 studies, the effects of mood on the formation of distinctiveness-based illusory correlations were examined. After exposure to stimuli inducing positive, neutral, or negative mood, Ss read information about behaviors performed by members of 2 groups in an illusory correlation paradigm. In both experiments, only Ss in a neutral mood formed illusory correlations. In addition, Experiment 2 assessed Ss' processing latencies as a means of investigating differential attention to distinctive behaviors. Only Ss in a neutral mood differentially attended to the minority group's infrequent behaviors. Induced mood apparently interfered with the processing necessary to differentially encode distinctive stimuli, undermining the illusory correlation effect.

The effect of acidosis on the relationship between Ca2+ and force in isolated ferret cardiac muscle

1. The relationship between force and intracellular [Ca2+] (monitored using the protein aequorin) has been investigated in papillary muscles isolated from ferret hearts, under control conditions (superfusate pH (pHo) 7.3) and during acidosis (pHo 6.8). 2. At pHo 7.3, increasing bathing [Ca2+] from 0.5 mmol l-1 to 8 mmol l-1 led to an increase in the size of the intracellular calcium transient. At the lower [Ca2+] this was accompanied by an increase in developed force; however, at the higher bathing [Ca2+] developed force reached a plateau. 3. Acidosis (produced by increasing the [CO2] of the gas with which the muscle superfusate was equilibrated) decreased maximum force and shifted the curve relating peak developed force to peak intracellular [Ca2+] to the right. 4. The mechanisms underlying the apparent decrease in the sensitivity of the contractile proteins to Ca2+ were investigated by applying rapid length changes to papillary muscles at control pHo, during acidosis, and after bathing [Ca2+] had been increased to match force during acidosis to that in control. 5. Acidosis decreased the change in force produced in response to a given length change (i.e. decreased muscle stiffness) but when bathing [Ca2+] was increased during acidosis, muscle stiffness returned to control. 6. Acidosis had no effect on muscle stiffness after the induction of rigor in the muscle (produced by metabolic inhibition). 7. It is suggested that in intact cardiac muscle the major effect of a mild acidosis is to decrease the sensitivity of the contractile proteins to Ca2+, hence decreasing the number of bound cross-bridges.

The effects of thiamin on lead metabolism: whole body retention of lead-203

The effects of thiamin on the whole body retention of led were evaluated in CD-1 mice treated intragastrically or intraperitoneally while exposed to a single dose of lead acetate (100 micrograms) containing 100 mu Ci lead-203. They were administered thiamin (25 or 50 mg/kg body wt.), calcium ethylenediamine tetraacetic acid (CaEDTA) (50 mg/kg body wt.) or their combination in pretreatment or posttreatment regimens for 13 days. Both pre- and posttreatment with thiamin reduced the lead retention compared to the untreated lead-exposed mice, although the different patterns of lead retention were observed. The combined pretreatment (thiamin 50 mg/kg and CaEDTA) and the CaEDTA treatment alone reduced the whole body retention of lead most effectively. Thiamin, CaEDTA and the combined treatments decreased the absorption of lead-203 and the biological half-life of retained lead-203 following oral or intraperitoneal lead exposure. The reduced absorption and enhanced excretion of lead associated with thiamin administration may have therapeutic application for the treatment of lead poisoning.

Attribution difficulty and memory for attribution-relevant information

This research compared the processing and retrieval of attribution-relevant information when the attributional inference is easy or difficult to make. Subjects attributed behavioral events to the person or to the situation, based on several items of context information. Each context sentence implied either the person or the entity as causal agent. When the attributional inference was difficult to make (an equal number of context sentences implied actor and entity as the causal agent), subjects recalled more of the behavioral events, recalled more context sentences, and were less confident in their attributions than when the attributional inference was easy to make (most context sentences implied the same causal agent). Subjects also recalled context information that was implicationally incongruent with the majority of the other context sentences with a higher probability than when that same information was implicationally congruent.

Attribution difficulty and memory for attribution-relevant information

This research compared the processing and retrieval of attribution-relevant information when the attributional inference is easy or difficult to make. Subjects attributed behavioral events to the person or to the situation, based on several items of context information. Each context sentence implied either the person or the entity as causal agent. When the attributional inference was difficult to make (an equal number of context sentences implied actor and entity as the causal agent), subjects recalled more of the behavioral events, recalled more context sentences, and were less confident in their attributions than when the attributional inference was easy to make (most context sentences implied the same causal agent). Subjects also recalled context information that was implicationally incongruent with the majority of the other context sentences with a higher probability than when that same information was implicationally congruent.

Cognitive organization of impressions: effects of incongruency in complex representations

Two experiments investigated the organization in memory of expectancy-congruent and expectancy-incongruent information pertaining to multiple trait concepts in an impression-formation task. In Experiment 1, when multiple trait concepts were represented in the information describing the target person, both congruent and incongruent items reflecting the same trait concept were stored together and were directly associated in memory, and both types of items were recalled equally well. In Experiment 2, when only one trait concept was represented in the information, incongruent items were recalled with higher probability than congruent items, and the latter were not directly associated in memory. Results suggest that with increasing categorical complexity of stimulus information, processes are invoked that do not occur in simpler impression-formation contexts. Implications for theoretical models of person memory are discussed.

Ulcerogenic tumor syndrome of the pancreas associated with a nongastrin acid secretagogue

Among 30 patients with islet cell neoplasms or hyperplasia who exhibited marked gastric acid hypersecretion and peptic ulceration and/or diarrhea, fasting plasma gastrin concentrations were less than 150 pg/ml in 11 patients, whereas the remaining 19 patients had hypergastrinemia. Plasma extracts from seven of these 11 patients were assayed for acid secretagogue activity in rats. All seven plasma extracts had secretagogue activity that was not found in the plasma extracts of ten patients with ordinary duodenal ulcer disease. Each of the tumor or pancreatic tissue extracts obtained from nine patients exhibited secretagogue activity in rats even though tissue gastrin content was 101.9 pmol (213.8 ng).g-1 or less. The secretagogue activity of the tumor extracts was confirmed in conscious gastric fistula dogs. The tumors' secretagogue activity, in contrast to gastrin, was destroyed by trypsin. It was eluted between porcine motilin and human gastrin I from a Sephadex G-50 (Pharmacia LKB Biotechnology, Inc., Piscataway, NJ) superfine column and was not retained by CM-cellulose, at pH 8.5. Its retention time during reverse phase HPLC on a C18 column also differed from those of G17 and G34. Thus, this secretagogue activity appeared mediated by a small, acidic peptide with a molecular size of about 2000 to 3000 daltons. The present study indicates that plasma and tumor extracts of these 11 patients contain a gastric acid secretagogue activity mediated by a nongastrin peptide. We suggest that what may be a distinct clinical entity associated with endocrine neoplasms of the pancreas should be considered in the face of excessive acid hypersecretion without fasting hypergastrinemia.

Lionfish envenomation

Correct and immediate care can significantly reduce the debilitating effects of Scorpaenidae evenomation. The lack of immediate heat application to the wound in our case report may have contributed to the complications and eventual loss of motion in the affected area, since the toxic ingredient, a nondialyzable protein, remained active.