Calcium antagonists--clinical considerations

BACKGROUND: Postoperative nausea and vomiting (PONV) following major arthroplasty with spinal anaesthesia and intrathecal morphine is reported in 45-74% of patients. This randomised, double-blind, placebo-controlled trial was undertaken to determine whether a subhypnotic infusion of propofol has a prophylactic antiemetic effect in this patient population. METHODS: 82 patients undergoing hip or knee replacement under subarachnoid bupivacaine anaesthesia plus morphine 0.25 mg were randomised at the end of surgery to receive either propofol 30 mg x h(-1) or fat emulsion (Intralipid) 3 ml x h(-1) for 20 h postoperatively. Blinded observers recorded episodes of nausea, vomiting and pruritus. RESULTS: PONV in the intervention group was 40% vs 59% in the controls (P=0.1, not significant). Pruritus occurred in 34%, with a similar rate in both groups. CONCLUSION: These results suggest that routine use of postoperative, subhypnotic propofol infusion as PONV prophylaxis is not justified in this patient population.     

A comparison of prophylactic ondansetron hydrochloride and droperidol for strabismus repair in adults

BACKGROUND: Prophylactic administration of an antiemetic is a common procedure for patients undergoing strabismus surgery. Droperidol and ondansetron hydrochloride are commonly used antiemetics. This study compared the rates of postoperative nausea and vomiting (PONV) in adult patients undergoing strabismus surgery with prophylactically administered Droperidol or ondansetron hydrochloride. METHODS: A double-masked, randomized, prospective study was conducted comparing droperidol with ondansetron hydrochloride when administered prophylactically to adults undergoing strabismus surgery. RESULTS: Forty-five patients entered the study with a mean age of 30 years. Twenty percent of patients had nausea immediately postoperatively and 37% had nausea before discharge with no significant differences between groups. Overall rate of emesis, time in the recovery room, and time to discharge was not significantly different between the droperidol and ondansetron hydrochloride group. CONCLUSION: No real differences in the ability to prevent PONV between the two medications were found in this study.     

Antiemetic prophylaxis after laparoscopic cholecystectomy: comparative study of dehydrobenzperidol, metoclopramide, ondansetron and placebo

OBJECTIVES: To compare the efficacy of ondansetron to that of metoclopramide, dehydrobenzperidol and placebo for the prevention of postoperative nausea and vomiting (PONV) after laparoscopic cholecystectomy in a double-blind random study. PATIENTS AND METHOD: A total of 100 ASA I, II and III patients undergoing scheduled laparoscopic cholecystectomy were divided into 4 groups according to whether they received one of the following intravenously just prior to anesthetic induction: 1.25 mg dehydrobenzperidol (group D), 10 mg metoclopramide (group M), 4 mg ondansetron (group O) or 2 ml of saline (group P). All received general anesthesia with induction by thiopental, analgesia with fentanyl, muscle relaxation with atracurium and maintenance with oxygen-air and isoflurane. Episodes of nausea and/or vomiting during the first 24 h after surgery were recorded. Treatment was considered effective if no episodes occurred during this period. RESULTS: Nine of the 100 patients were excluded from the study. There were no significant differences in demographic variables among the 4 groups. The incidence of PONV was significantly greater in group P than in any of the other groups. There were no significant differences in PONV among groups D, M and O. CONCLUSIONS: Ondansetron provides safe, effective prophylaxis for PONV after laparoscopic cholecystectomy, but it is not superior to the antiemetic drugs usually used. Its use may be justified in patients in whom dehydrobenzperidol or metoclopramide are contraindicated.     

The effect of blockade of the AMPA/kainate receptors of the nucleus accumbens on synaptic dopamine release during an emotional conditioned response

We studied the effect of combining prophylactic ondansetron (4 mg intravenously [IV]) to desflurane-based anesthesia in 90 ASA grade I or 11 women undergoing outpatient gynecological laparoscopy. Recovery after anesthesia, with special focus on postoperative nausea and vomiting (PONV), was assessed. Control groups received a similar desflurane anesthetic (placebo) or a propofol-infusion-based (active control) anesthetic. The study design was randomized, controlled, and double-blind (regarding ondansetron) and single-blind (regarding the anesthetic technique). Early recovery (eye opening, orientation, following commands, sitting) was similar in the three groups. However, overall home readiness (toleration of oral fluids, walking, pain tolerable by oral analgesics, no or only mild nausea) was achieved faster in the desflurane group receiving ondansetron (109 [21-937] min, P < 0.01) and in the propofol group (110 [33-642] min, P < 0.001) when compared to the desflurane only group (372 [45-723] min) (median [range]). The total incidence of PONV in the desflurane-only group was 80% (P < 0.01), compared to 40% and 20% in the desflurane group receiving ondansetron and the propofol group, respectively. The postoperative antiemetic requirements were consistently and significantly (P < 0.01) higher in the desflurane-only group compared to the other two groups. Postoperative sedation, analgesic requirements, and psychomotor recovery (assessed by the Maddox Wing and the Digit Symbol Substitution Tests) were similar in the three groups. Our results suggest that in order to achieve a propofol-like recovery profile in patients with a high likelihood of PONV, desflurane should be combined with a potent antiemetic (e.g., ondansetron).     

Destruction of the auditory thalamus disrupts the production of fear but not the inhibition of fear conditioned to an auditory stimulus

Although ondansetron (4 mg I.V.) is effective in the prevention and treatment of postoperative nausea and vomiting (PONV) after ambulatory surgery, the optimal timing of its administration, the cost-effectiveness, the cost-benefits, and the effect on the patient's quality of life after discharge have not been established. In this placebo-controlled, double-blind study, 164 healthy women undergoing outpatient gynecological laparoscopic procedures with a standardized anesthetic were randomized to receive placebo (Group A), ondansetron 2 mg at the start of and 2 mg after surgery (Group B), ondansetron 4 mg before induction (Group C), or ondansetron 4 mg after surgery (Group D). The effects of these regimens on the incidence, severity, and costs associated with PONV and discharge characteristics were determined, along with the patient's willingness to pay for antiemetics. Compared with ondansetron given before induction of anesthesia, the administration of ondansetron after surgery was associated with lower nausea scores, earlier intake of normal food, decreased incidence of frequent emesis (more than two episodes), and increased times until 25% of patients failed prophylactic antiemetic therapy (i.e., had an emetic episode or received rescue antiemetics for severe nausea) during the first 24 h postoperatively. This prophylactic regimen was also associated with the highest patient satisfaction and lowest cost-effectiveness ratios. Compared with the placebo group, ondansetron administered after surgery significantly reduced the incidence of PONV in the postanesthesia care unit and during the 24-h follow-up period and facilitated the recovery process by reducing the time to oral intake, ambulation, discharge readiness, resuming regular fluid intake and a normal diet. When ondansetron was given as a "split dose," its prophylactic antiemetic efficacy was not significantly different from that of the placebo group. In conclusion, the prophylactic administration of ondansetron after surgery, rather than before induction, may be associated with increased patient benefits. Implications: Ondansetron 4 mg I.V. administered immediately before the end of surgery was the most efficacious in preventing postoperative nausea and vomiting, facilitating both early and late recovery, and improving patient satisfaction after outpatient laparoscopy.     

Antiemetic efficacy of prophylactic ondansetron in laparoscopic surgery: randomized, double-blind comparison with metoclopramide

In a randomized, double-blind study, we have compared the prophylactic antiemetic efficacy of ondansetron with that of metoclopramide in 123 patients undergoing general anaesthesia for day-case gynaecological laparoscopic surgery. The patients received either i.v. ondansetron 4 mg or metoclopramide 10 mg immediately before a standard anaesthetic. The number of patients with no nausea or vomiting in the ondansteron group was 50 (82%) compared with 29 (47%) in the metoclopramide group (P < 0.001). In those patients with a previous history of postoperative nausea and vomiting, nausea was less severe in those receiving ondansetron compared with those receiving metoclopramide (P < 0.05). We conclude that preoperative prophylactic administration of i.v. ondansetron was superior to metoclopramide in preventing nausea and vomiting after general anaesthesia for day-case gynaecological laparoscopic surgery.     

Ondansetron versus droperidol or placebo to prevent nausea and vomiting after otologic surgery

This study compares the preoperative administration of ondansetron with that of droperidol or saline solution for the prevention of nausea and vomiting in otologic surgery patients. A total of 120 otherwise healthy individuals were randomly assigned to receive either saline solution, ondansetron (4 mg intravenously), or droperidol (25 microg/kg intravenously) before anesthetic induction. Intraoperative and postanesthesia care unit times were recorded along with incidence of nausea, vomiting, pain, nausea and recovery scores, and the administration of rescue antiemetics. Similar assessments were made during the next 24 hours. Demographics were similar, but more males received ondansetron. Anesthetic recovery scores were lower after administration of droperidol than after ondansetron. Incidence of nausea was similar between groups, but severity was greater with placebo and droperidol than with ondansetron. More vomiting occurred with placebo than with ondansetron or droperidol. No intergroup differences in rescue antiemetic administration were noted, however. Twenty-four hours later, more patients receiving placebo had nausea or vomited than patients receiving droperidol or ondansetron. Fewer women in the ondansetron group vomited than in the other two groups. Ondansetron 4 mg intravenously is as effective as droperidol and better than saline solution in preventing nausea and vomiting in patients undergoing otologic surgery. No cost advantage as determined by lower use of rescue antiemetics or shorter postanesthesia care unit times was noted after ondansetron therapy.     

Agonist action at D2(long) dopamine receptors: ligand binding and functional assays

Clinical pathways are being introduced by hospitals to reduce costs and control unnecessary variation in care. We studied 766 inpatients to measure the impact of a perioperative clinical pathway for patients undergoing knee replacement surgery on hospital costs. One hundred twenty patients underwent knee replacement surgery before the development of a perioperative clinical pathway, and 63 patients underwent knee replacement surgery after pathway implementation. As control groups, we contemporaneously studied 332 patients undergoing radical prostatectomy (no clinical pathway in place for these patients) and 251 patients undergoing hip replacement surgery without a clinical pathway (no clinical pathway and same surgeons as patients having knee replacement surgery). Total hospitalization costs (not charges), excluding professional fees, were computed for all patients. Mean (+/-SD) hospital costs for knee replacement surgery decreased from $21,709 +/- $5985 to $17,618 +/- $3152 after implementation of the clinical pathway. The percent decrease in hospitalization costs was 1.56-fold greater (95% confidence interval 1.02-2.28) in the knee replacement patients than in the radical prostatectomy patients and 2.02-fold greater (95% confidence interval 1.13-5.22) than in the hip replacement patients. If patient outcomes (e.g., patient satisfaction) remain constant with clinical pathways, clinical pathways may be a useful tool for incremental improvements in the cost of perioperative care. Implications: Doctors and nurses can proactively organize and record the elements of hospital care results in a clinical pathway, also known as "care pathways" or "critical pathways." We found that implementing a clinical pathway for patients undergoing knee replacement surgery reduced the hospitalization costs of this surgery.     

Modified oral ondansetron regimen for cyclophosphamide-induced emesis in lupus nephritis

OBJECTIVE: To evaluate the antiemetic efficacy of a modified regimen of oral ondansetron and dexamethasone in patients with lupus nephritis undergoing treatment with cyclophosphamide whose conventional antiemetic regimen had failed. DESIGN: A before-after prospective observational pilot project. SETTING: A federal research hospital. PATIENTS: Fourteen outpatients with lupus nephritis receiving intravenous cyclophosphamide 0.75-1.0 g/m2 had previously experienced chemotherapy-induced emetic events (vomiting or retching) while receiving a standard combination intravenous antiemetic regimen. The regimen consisted of four doses of thiethylperazine 10 mg and diphenhydramine 25 mg every 6 hours, and two doses of lorazepam 0.5 mg every 6 hours starting at 1 hour prior to cyclophosphamide. A subset of 8 patients previously completed a blinded study in which they received the intravenous formulation of ondansetron (4 doses of 4-16 mg q4h) administered orally beginning 30 minutes prior to the cyclophosphamide infusion. MAIN OUTCOME MEASURES: The number of emetic events and cost of drug administration were assessed for the modified ondansetron intervention and compared with those of the standard antiemetic regimen. The incidence of emetic events and visual analog nausea scores for the subset of eight patients were also evaluated. INTERVENTIONS: To account for the delayed onset of emesis associated with cyclophosphamide, patients received both ondansetron 8 mg orally every 4 hours (3 doses) and dexamethasone 10 mg orally (1 dose) beginning 4 hours after the cyclophosphamide infusion. This is different from the manufacturer's recommended dose schedule, in which ondansetron is administered prior to chemotherapy. RESULTS: No emetic events were observed following the administration of oral ondansetron/dexamethasone. The 95% confidence interval for the true rate of emesis was 0% to 19.3%. There was a significant difference in efficacy between ondansetron/dexamethasone and the triple antiemetic regimen (p < 0.0002). None of the patients experienced adverse effects while receiving the ondansetron/dexamethasone regimen. Cost comparisons (including admixture and nursing administration times) for standard combination therapy and oral ondansetron/dexamethasone were $109.09 and $70.24, respectively. No difference in emetic events or nausea ratings was observed between oral ondansetron/dexamethasone tablets and oral administration of ondansetron using the intravenous formula. CONCLUSIONS: This study suggests that a modified oral ondansetron/dexamethasone regimen is safe and efficacious, and costs less than alternative regimens to prevent cyclophosphamide-induced emesis in patients with lupus nephritis.     

Intravenous dolasetron and ondansetron in prevention of postoperative nausea and vomiting: a multicenter, double-blind, placebo-controlled study

BACKGROUND: Intravenous dolasetron mesilate has shown efficacy in the prevention of postoperative nausea and vomiting (PONV) when administered as a single dose prior to emergence from anesthesia. This trial compared intravenous dolasetron and ondansetron for the prevention of PONV when administered at induction of anesthesia. METHODS: This double-blind, placebo-controlled, multicenter trial randomized patients to one of four single IV treatments placebo, 25 or 50 mg dolasetron, or 4 mg ondansetron. Efficacy was measured by complete response (0 emetic episodes and no rescue medication), nausea severity and patient satisfaction as measured on a visual analog scale (VAS), investigator's rating, of nausea severity, and total response (complete response with no nausea [< or = 5 mm VAS]). RESULTS: 514 patients at 24 sites were evaluated for efficacy. The 50 mg dolasetron and 4 mg ondansetron doses were statistically equivalent, and superior to placebo, for all efficacy measures. Complete response rates were 49%, 51%, 71% and 64% for placebo, 25 and 50 mg dolasetron, and ondansetron, respectively. Dolasetron 50 mg was statistically superior to 25 mg dolasetron for complete response, total response, VAS maximum nausea, time to first emetic episode, and patient satisfaction. The majority of adverse events were of mild-to-moderate intensity. Headache was the most frequently reported treatment-related adverse event with a 3%-5% incidence across treatments. CONCLUSION: When given at induction of anesthesia, 50 mg intravenous dolasetron is equivalent to 4 mg ondansetron and superior to 25 mg dolasetron and placebo for the prevention of PONV. All treatments were safely administered and well tolerated.     

Comparison of single-dose oral granisetron versus intravenous ondansetron in the prevention of nausea and vomiting induced by moderately emetogenic chemotherapy: a multicenter, double-blind, randomized parallel study

PURPOSE: The antiemetic effectiveness and safety of single-dose oral granisetron were compared with intravenous (I.V.) ondansetron in chemotherapy-naive patients who received moderately emetogenic chemotherapy. PATIENTS AND METHODS: In this double-blind, parallel-group study, patients naive to emetogenic chemotherapy (N = 1,085) who were scheduled to receive cyclophosphamide- (500 to 1,200 mg/m2) or carboplatin (> or = 300 mg/m2) based chemotherapy, were randomized to receive either oral granisetron (n = 542) or I.V. ondansetron (n = 543). Efficacy assessments included the proportion of patients in each treatment group with total control over the 24 and 48 hours following chemotherapy initiation, as well as incidence and severity of nausea and emesis and use of antiemetic rescue medication. Prophylactic corticosteroids were allowed. Safety assessment was based on patients' reports of adverse experiences. RESULTS: Approximately 80% of patients received prophylactic corticosteroids. Single-dose oral granisetron (2 mg) and I.V. ondansetron (32 mg) resulted in equivalent levels of total emetic control during the first 48 hours after chemotherapy. The proportion of nausea- and emesis-free patients at 24 and 48 hours were also approximately equivalent. The most commonly reported adverse experiences were headache, asthenia, and constipation. More patients who received ondonsetron than granisetron reported dizziness (9.6% v 5.4%, respectively; P = .011) and abnormal vision (4.2% v 0.6%, respectively; P < .001). CONCLUSION: A single oral dose of granisetron (2 mg) resulted in equivalent levels of antiemetic protection as I.V. ondansetron (32 mg). Both agents were well tolerated, although more dizziness and abnormal vision were reported with ondansetron. Because the two antiemetic regimens exhibited equivalent efficacies, additional factors such as convenience and cost of therapy should be considered.     

Ondansetron for prevention of postoperative nausea and vomiting following minor oral surgery: a double-blind randomized study

The efficacy and safety of ondansetron in preventing postoperative nausea and vomiting following minor oral surgery was evaluated in a prospective randomized double-blind study. Of a total of seventy-seven patients, randomly 38 had 4 mg of ondansetron and 39 had normal saline as placebo intravenously immediately prior to induction of anaesthesia. A standard general anaesthetic with thiopentone, suxamethonium, fentanyl, nitrous oxide and isoflurane was employed. Postoperatively nausea was assessed verbally and on a visual analog scale at 1, 4 and 24 hours from the time of awakening. Episodes of vomiting were recorded. Eight patients (21.1%) in the ondansetron group compared to 19 (48.7%) in the placebo group had nausea (P < 0.05) and 1 (2.6%) in the ondansetron group compared with 9 (23.1%) in the placebo group vomited (P < 0.05). Patients who vomited twice or more and the number who required a rescue antiemetic were significantly fewer in the ondansetron group (P < 0.05). Cardiovascular parameters were stable and showed no significant difference in the two groups. There were no significant adverse effects that could be directly attributable to ondansetron.     

Hormone replacement therapy and risk of hip fracture: population based case-control study. The Swedish Hip Fracture Study Group

OBJECTIVE: To determine the relative risk of hip fracture associated with postmenopausal hormone replacement therapy including the effect of duration and recency of treatment, the addition of progestins, route of administration, and dose. DESIGN: Population based case-control study. Setting: Six counties in Sweden. SUBJECTS: 1327 women aged 50-81 years with hip fracture and 3262 randomly selected controls. MAIN OUTCOME MEASURE: Use of hormone replacement therapy. RESULTS: Compared with women who had never used hormone replacement therapy, current users had an odds ratio of 0.35 (95 % confidence interval 0.24 to 0.53) for hip fracture and former users had an odds ratio of 0.76 (0.57 to 1.01). For every year of therapy, the overall risk decreased by 6% (3% to 9%): 4% (1% to 8%) for regimens without progestin and 11% (6% to 16%) for those with progestin. Last use between one and five years previously, with a duration of use more than five years, was associated with an odds ratio of 0.27 (0.08 to 0.94). After five years without hormone replacement therapy the protective effect was substantially diminished (-7% to 48%). With current use, an initiation of therapy nine or more years after the menopause gave equally strong reduction in risk for hip fracture as an earlier start. Oestrogen treatment with skin patches gave similar risk estimates as oral regimens. CONCLUSIONS: Recent use of hormone replacement therapy is required for optimum fracture protection, but therapy can be started several years after the menopause. The protective effect increases with duration of use, and an oestrogen-sparing effect is achieved when progestins are included in the regimen.     

Prophylactic oral antiemetics for preventing postoperative nausea and vomiting: granisetron versus domperidone

In this prospective, randomized, double-blinded study, we evaluated the efficacy of the oral antiemetics, granisetron and domperidone, for the prevention of postoperative nausea and vomiting (PONV) in 100 women undergoing major gynecologic surgery. Patients received either granisetron 2 mg or domperidone 20 mg (n = 50 in each group) orally 1 h before surgery. Standardized anesthetic techniques and postoperative analgesia regimens were used. Complete response (defined as no PONV and no administration of rescue antiemetic medication) for 0-3 h after anesthesia was 88% with granisetron and 52% with domperidone; the corresponding incidence for 3-24 h after anesthesia was 86% and 48% (P < 0.05). No clinically important adverse events due to the drugs were observed in any of the groups. In conclusion, the efficacy of preoperative oral granisetron is superior to that of domperidone for the prevention of PONV after major gynecologic surgery. IMPLICATIONS: We compared the efficacy of granisetron and domperidone administered orally for the prevention of postoperative nausea and vomiting in women undergoing gynecologic surgery. Preoperative oral granisetron was more effective than domperidone.     

Ontogenic development of the adenylyl cyclase enzyme and the alpha s, alpha i1 and alpha i2 G-protein regulatory subunits from rat prostate

STUDY OBJECTIVE: To compare the prophylactic administration of ondansetron with droperidol or placebo to determine its effectiveness in reducing postoperative nausea and vomiting after middle ear procedures. DESIGN: Prospective, randomized, double-blind study. SETTING: Inpatient otolaryngology service at a university medical center. PATIENTS: 120 ASA physical status I and II patients presenting for elective middle ear surgical procedures. INTERVENTIONS: Patients were randomly assigned to receive either placebo (Group 1), ondansetron 4 mg intravenously (IV) (Group 2), or droperidol 25 mcg/kg i.v. (Group 3) 10 minutes before induction of general anesthesia using thiopental 5 mg/kg i.v. with fentanyl 2 mcg/kg i.v. and maintenance anesthesia with isoflurane 1% to 2% end-tidal in a 50% air/oxygen mixture. MEASUREMENTS AND MAIN RESULTS: Total surgical, anesthesia, extubation, and postanesthesia care unit (PACU) occupancy times were recorded along with anesthesia recovery scores. The incidence and severity of nausea, vomiting, and pain along with rescue antiemetic administration, also were recorded. Similar assessments were made over the next 24 hours. Intergroup demographic data were similar except that the male to female ratio was higher in the ondansetron group. Stewart scores, reflecting emergence from anesthesia, were higher with ondansetron compared with droperidol. The incidence of nausea was similar between the groups but the severity was less after ondansetron therapy. More patients vomited after placebo than when given either droperidol or ondansetron. No intergroup differences were noted in the use of rescue antiemetics. Twenty-four hours later, more patients who received the placebo drug had nausea or vomited compared with either ondansetron or droperidol. CONCLUSIONS: Ondansetron 4 mg i.v. is as effective as droperidol and better than placebo in preventing nausea and vomiting in patients undergoing middle ear surgery. No cost advantage as determined by lower use of rescue antiemetics or shorter PACU times was noted after the prophylactic administration of ondansetron.     

Efficacy and tolerability of oral ondansetron versus prochlorperazine in the prevention of emesis associated with cyclophosphamide-based chemotherapy and maintenance of health-related quality of life

This study compared the efficacy and tolerability of oral ondansetron (8 mg twice daily [BID] for up to 3 days) with those of phenothiazine prochlorperazine (10 mg BID for up to 3 days) in 133 cancer patients receiving cyclophosphamide-based chemotherapy. In addition, the study evaluated the impact of these treatments on patients' health-related quality of life, measured with both the Functional Living Index--Cancer and the Functional Living Index--Emesis questionnaires. The first dose of study drug was administered 30 minutes before initiation of chemotherapy. Patients received a rescue antiemetic at their request or if the investigator deemed it necessary. There was a statistically significant difference in the number of patients with no emetic episodes over the 3-day study period: 60% in the ondansetron group compared with 21% in the prochlorperazine group. Twenty-five percent of ondansetron-treated patients compared with 68% of prochlorperazine-treated patients experienced three or more emetic episodes, rescue medication use, or withdrawal from the study due to adverse events or lack of efficacy of the study drug. Among patients with at least one emetic episode, the mean time to emesis was significantly longer (13 hours and 37 minutes) in the ondansetron group compared with the prochlorperazine group (9 hours and 30 minutes). Nausea and appetite scores did not differ significantly between groups. The score on the vomiting subscale of the Functional Living Index--Emesis was significantly more favorable in the ondansetron group compared with the prochlorperazine group, indicating better maintenance of health-related quality of life in ondansetron-treated patients. Both treatments were well tolerated. The most common potentially drug-related adverse event was headache, which occurred in significantly more (16%) ondansetron-treated patients compared with prochlorperazine-treated patients (3%). The results of this study demonstrate that oral ondansetron 8 mg BID for up to 3 days is more effective than prochlorperazine 10 mg BID for up to 3 days in the prevention of emesis associated with moderately emetogenic chemotherapy.     

Venous haemodynamics in both legs after total knee replacement

We studied the effect of total knee replacement on venous flow in 110 patients. Resting venous blood flow was measured using strain-gauge plethysmography before operation, after surgery and after discharge from hospital. There was a significant reduction in mean venous capacitance (p < 0.001) and mean venous outflow (p < 0.004) affecting only the operated leg. Both improved significantly after mobilisation in the early postoperative period, returning to preoperative levels by six days after surgery and before discharge from hospital. Our findings showed that venous stasis may contribute to deep-vein thrombosis only in the first few days after total knee replacement. This would be the most important period for the use of flow-enhancing prophylactic devices. Comparison with changes in blood flow after total hip replacement identified different patterns of altered haemodynamics suggesting that there are different mechanisms of venous stasis and thrombogenesis in hip and knee arthritis and during surgery for these conditions.     

Minimum specimen volume requirements for routine coagulation testing: dependence on citrate concentration

An audit of post-operative nausea and vomiting (PONV) was undertaken in 935 female patients who used morphine patient-controlled analgesia (PCA) for pain relief after major gynaecological operations in a district general hospital. We investigated retrospectively five different antiemetic policies and a reference group without policy from January 1993 to July 1995. The department's computerized audit system was used to analyse the observations. At the beginning of the audit, the incidence of nausea and vomiting was as high as 71.5%. But as a consequence of this audit, a departmental policy was adopted 3 years later, which had an incidence of PONV of only 51.7%. During this time the compliance with antiemetic protocols increased from 41% to 76%. There was significantly less PONV if an antiemetic protocol was followed (P = 0.002). This emphasizes the importance of corporate involvement in the development, formulation and evaluation of departmental protocols if compliance is to be high. We conclude that audit as a corporate effort improves the acceptance of departmental protocols. This reduces PONV significantly irrespective of the type of antiemetic drug used.     

In vitro effect of ketones and hyperglycemia on feline hemoglobin oxidation and D- and L-lactate production

Postoperative nausea and vomiting (PONV) are unpleasant, often underestimated side effects of anaesthesia and surgery, not devoid of medical complications. Prevention with antiemetics is only partially effective. Propofol has been shown recently to possess antiemetic properties in several situations. In this prospective, randomized, controlled trial, we have compared the antiemetic efficacy of subhypnotic doses of propofol, with Intralipid as placebo, after thyroidectomy. We studied 64 patients of both sexes, aged 22-71 yr, ASA I or II, undergoing thyroidectomy. After premedication with a benzodiazepine, balanced anaesthesia was produced with isoflurane and nitrous oxide in oxygen, and supplementary analgesia with fentanyl i.v. as required. Postoperative analgesia was provided with non-opioids, and piritramide 0.25 mg kg-1 i.m. on demand. Patients were allocated randomly and blindly to receive a 20-h infusion of either propofol or 10% Intralipid 0.1 ml kg-1 h-1. Intralipid, the excipient of propofol, was chosen as placebo as it is devoid of antiemetic effects. Sedation scores, respiratory and cardiovascular variables, and incidence of PONV were assessed every 4 h for 24 h. Pulse oximetry and ECG were monitored continuously. Both groups were comparable in characteristics, surgical and anaesthesia procedures, amount of opioids given during and after operation, and total amount of the study drug infused after operation. Occurrence of PONV was similar before the start (propofol 41%, Intralipid 50%) and after completion (propofol 0.64%, Intralipid 1.6%) of infusion and decreased with time in both groups during the infusion. However, symptoms were reduced to nil with propofol but persisted and were more severe with Intralipid during infusion (P < or = 0.01). The overall incidence of PONV during infusion was 10% (three of 32 patients) in the propofol group and 65% (21 of 32 patients) in the Intralipid group. Cardiovascular and respiratory variables, and SpO2 were unaltered, and sedation decreased similarly with time in both groups. We conclude that propofol, given at subhypnotic doses, effectively reduced the incidence of PONV without untoward sedative or cardiovascular effects.     

Antiemetic prophylaxis does not improve outcomes after outpatient surgery when compared to symptomatic treatment

BACKGROUND: Although prophylactic administration of antiemetics reduces the incidence of postoperative nausea, vomiting, or both (PONV), there is little evidence to suggest this improves patient outcomes. The authors hypothesized that early symptomatic treatment of PONV will result in outcomes, including time to discharge, unanticipated admission, patient satisfaction, and time to return to normal daily activities, that are similar to those achieved with routine prophylaxis. METHODS: Men and women (n = 575) scheduled for outpatient surgery during general anesthesia were randomized to receive either 4 mg intravenous ondansetron or placebo before operation and either 1 mg intravenous ondansetron or placebo if postoperative symptomatic treatment of PONV was necessary. Patients were stratified into subgroups by risk factors for PONV. RESULTS: No differences occurred in the time to discharge, rate of unanticipated admission, or time to return to normal activity between the prophylaxis and treatment groups. The reported level of satisfaction with control of PONV was 93% in the treatment arm and 97% in the prophylaxis arm, which fall within the limits defined a priori as clinically equivalent. Female patients with a history of motion sickness or PONV who were undergoing highly emetogenic procedures had a higher reported level of satisfaction with prophylaxis than with treatment (100% vs. 90%, P = 0.043); however, the level of satisfaction with the overall outpatient surgical experience was not different. CONCLUSION: Although PONV is unpleasant, the data indicate little difference in outcomes when routine prophylactic medications are administered versus simply treating PONV should symptoms occur.