Perioperative Care

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Protein Restriction in Chronic Renal Failure

J. E. KIST-VAN HOLTHE TOT ECHTEN, J. NAUTA, W. C. J. HOP, M. C. J. w. DE JON G, w. C. C. REITSMA-BIERENS, S. L. B. PLOOS VAN AMSTEL, K. J. VAN ACKER, C. M. NOORDZIJ AND E. D. WOLFF, Department of Paediatrics, Subdivision Nephrology, Sophia Children 's Hospital, and De­ partment of Epidemiology and Biostatistics, University Hos­ pital, Rotterdam, and Departments of Paediatrics, Subdivi­ sions Nephrology, University Hospitals, Nijmegen, Groningen and Antwerp, and Academic Medical Centre, Amsterdam, The Netherlands Arch. Dis. Child., 68: 371-375, 1993 The aim of the study was to investigate the effect of a protein restricted diet on renal function and growth of children with chronic renal failure. In a rnulticentre prospective study 56 children (aged 2-18 years) with chronic renal failure were randomly assigned to the protein restricted (0.8-1.1 g/kg/day) or the control group. All children were followed up by the same paediatrician and dietitian. After a follow up period of three years there was no significant difference in glomerular filtration rate between children on a protein restricted diet and children of the control group. There was no significant difference in weight with respect to height and height SD score between the protein restricted and the control group. Compliance with the protein restricted diet, as indicated by the prospective diet diaries and the serum urea:creatinine ratio, was good. This study shows that children with chronic renal failure do not benefit from a protein restricted diet.

Editorial Comment: From experimental work it has been hypothesized that in the presence of reduced renal mass protein restriction can decrease hyperfiltration and slow progression of chronic renal failure. However, whether protein restriction is beneficial in the human is controversial. The authors studied 56 children with a glomerular filtration rate between 1 5 and 6 0 ml. per minute per 1 . 73 m. 2 (mean 40) and placed half on a restricted protein diet for 3 years. No difference was found in ultimate renal function between the 2 groups. Consequently, despite the theoretical benefit of protein restriction in terms of maintaining renal function in children with renal insufficiency, no benefit could be demonstrated and such a diet is not advisable. Jack S. Elder, M.D. Why are Children Referred for Circumcision?

N. WILLIAMS, J. CHELL AND L. KAPILA, Department of Pae­ diatric Surgery, University Hospital, Queens Medical Centre, Nottingham, England

Brit. Med. J., 306: 28, 1993 No Abstract

Editorial Comment: At age 1 year 50% of all boys have a completely retractable foreskin; by 5 years it is re­ tractable in 90% and by adolescence the percentage increases to 99%. In this report of 69 children referred for a penile problem that might require circumcision more than 70% had phimosis or a tight foreskin and 1 2 % had a history of balanitis. In the United States many families of uncircumcised children are given mis­ information regarding appropriate care of the penis and

may be told to retract the foreskin forcefully to clean the glans. If the prepuce is retracted traumatically re­ sulting in tearing of the foreskin, secondary phimosis may result. In a 4 or 5-year-old boy with phimosis one needs to distinguish between physiological phimosis, in which the foreskin has never been retracted, and path­ ological phimosis, in which the foreskin has scarring from previous retraction. The latter group of patients may exhibit ballooning of the prepuce during voiding. The distinction between these 2 conditions is important because a boy with physiological phimosis ultimately will have a retractable foreskin, whereas a boy with secondary phimosis should undergo circumcision or have the phimotic ring broken. Jack S. Elder, M.D. Recommended Reading: 1. Proceedings of the First International Conference on Mo­ lecular and Clinical Genetics of Childhood Renal Tumors, May 14-16, 1992. Med. Ped. Oncol., 2 1: 155-237, 1993. 2. Redline, R. W., Williams, A. J., Patterson, P. and Collins, T .: Human HOX4E: a gene strongly expressed in the adult male and female urogenital tracts. Genomics, 13: 425, 1992.

PERIOPERATIVE CARE

The Incidence of Perioperative Myocardial Infarction in Men Undergoing Noncardiac Surgery

C. M. ASHTON, N. J. PETERSEN, N. P. WRAY, C. I. KIEFE, J. K. DUNN, L. Wu AND J. M. THOMAS, Veterans Affairs Medical Center, Houston, Texas Ann. Intern. Med., 1 1 8 : 504-510, 1993 Objectives: To determine the incidence of and risk factors for perioperative myocardial infarction with noncardiac surgery and to test the accuracy of a risk stratification system. Design: Prospective cohort study. Setting: A large urban Veterans Affairs hospital. Participants: A total of 1487 men older than 40 years undergoing major, nonemergent, noncardiac operations. Measurements: Infarction was established by at least two of the following: development of new Q waves, typical change in creatine kinase MB, and positive technetium pyrophosphate scintigraphy. Patients were stratified preoperatively into high-, intermediate-, low-, and negligible-risk strata based on clinical markers corresponding to different levels of coronary artery disease prevalence. Main Results: Patients with coronary disease (high-risk stra­ tum) had a 4.1 % incidence of infarction (13 of 319; 95% CI, 1.8% to 6.4%); patients with peripheral vascular disease but no evidence of coronary disease (intermediate-risk stratum) had a 0.8% incidence (2 of 260, upper bound of Cl, 2.0%); patients with high atherogenic risk factor profiles but no clinical ath­ erosclerosis (low-risk stratum) had a 0 % incidence (O of 256, upper bound of CI, 1.2%). No cardiac deaths occurred in 652 men who had no atherosclerosis and low atherogenic risk factor profiles (the negligible-risk stratum). Factors independently associated with infarction included age more than 75 years (adjusted odds ratio, 4. 77; CI, 1.17 to 19.41), signs of heart failure on the preoperative examination (adjusted odds ratio, 3.31; CI, 0.96 to 1 1.38), coronary disease (adjusted odds ratio, 10.39; CI, 2.27 to 47.46), and a planned vascular operation (adjusted odds ratio, 3.72; CI, 1.12 to 12.37).

PERIOPERATIVE CARE

Conclusions: Coronary artery disease is the major risk factor for perioperative infarction. The stratification scheme identi­ fies subsets of patients with different risks, and finer within­ stratum distinctions can be made using additional variables.

E ditorial Comment: The goal of this prospective study was to determine the incidence of and risk factors for perioperative myocardial infarction in men undergoing noncardiac surgery. Coronary artery disease was the major risk factor for perioperative infarction: there was a 4. 1 % incidence of infarction in men with coronary artery disease, and 1 3 of 1 5 men (87%) who suffered a perioperative myocardial infarction in the study had coronary artery disease. Men with peripheral vascular disease had a lower risk of infarction, and no infarctions occurred in men without clinical atherosclerosis, re­ gardless of whether they had a high or low atherogenic risk factor profile. Therefore, efforts to reduce periop­ erative cardiac morbidity should focus on men known to have coronary artery disease. Charles B . Brendler, M.D. Unintentional Hypothermia is Associated With Postop­ erative Myocardial Ischemia

8. M. FRANK, C. BEATTIE, R. CHRISTOPHERSON, E. J. NORRIS, B. A. PERLER, G. M. WILLIAMS, S. 0. GOTTLIEB AND THE PERIOPERATIVE ISCHEMIA RANDOMIZED ANESTHESIA TRIAL STUDY GROUP, Johns Hopkins Medical Institutions, Balti­

more, Maryland

Anesthesiology, 78: 468-476, 1993 Background: Hypothermia occurs commonly during surgery and can be associated with increased metabolic demands during rewarming in the postoperative period. Although cardiac com­ plications remain the leading cause of morbidity after anes­ thesia and surgery, the relationship between unintentional hypothermia and myocardial ischemia during the perioperative period has not been studied. Methods: One hundred patients undergoing lower extremity vascular reconstruction received continuous Holter monitoring throughout the first 24 h postoperatively. Myocardial ischemia was determined by a cardiologist masked to clinical variables. The patient's sublingual temperature on arrival at the intensive care unit immediately after the surgical procedure was used to divide the patients into two groups: hypothermic (temperature, <35 ° C; n = 33) and normothermic (temperature, =:::35 ° C; n = 67). The relationship between unintentional hypothermia and myocardial ischemia occurring during the first postoperative day was evaluated by univariate and multivariate analyses. Results: A greater percentage of patients had electrocardi­ ographic changes consistent with myocardial ischemia in the hypothermic group (36%, 12 of 33) compared with those in the normothermic group (13 % , 9 of 67, P = 0.008). Preoperative risk factors for perioperative cardiac morbidity were similar between the two groups, except for patient age. The mean age was 70 ± 2 yr and 62 ± 1 year in the hypothermic and normothermic groups, respectively (P = 0.001). When subgroup and multivariate analyses were used to adjust for differences in age, temperature remained an independent predictor of ische­ mia (odds ratios, 1.82 per degree Celsius; 95% confidence inter­ val, 1.09-3.02). The incidence of postoperative angina was greater in the hypothermic group (18%, 6 of 33) than in the

1343

normothermic group (1.5% , 1 of 67, P = 0.002). The incidence of Pao2 < 80 mmHg in the arterial blood was greater in the hypothermic group (52%, 17 of 33) than in the normothermic group (30 % , 20 of 67, P = 0.03). Conclusions: Unintentional hypothermia is associated with myocardial ischemia, angina, and Pao2 < 80 mmHg during the early postoperative period in patients undergoing lower extrem­ ity vascular surgery.

Editorial Comment: In this study of men undergoing lower extremity vascular surgery there was a signifi­ cant association between unintentional hypothermia and early postoperative myocardial ischemia. Of the hypothermic patients (temperature less than 35C) 36% experienced electrocardiographic changes of ischemia during the first 24 hours, compared to only 1 3 % of those in the normothermic group. It seems important to pre­ vent hypothermia, particularly in patients already at increased risk (such as those with known coronary ar­ tery disease) for perioperative myocardial infarction. Charles B. Brendler, M.D. Transoesophageal Stress Echocardiography for Pre­ Operative Detection of Patients at Risk of Intra­ Operative Myocardial Ischaemia R. HOFFMANN,

H . LAMBERTZ , H. KASMACHER, l. LIEBICH, F. A. FLACHSKAMPF, M. PLUM AND P. HANRATH , Medical

Clinic I and Department ofAnaesthesiology, Klinikum R WTH Aachen, Aachen, Germany Eur. Heart J., 1 3 : 1482-1488, 1992

Patients with coronary artery disease have an increased risk of developing intra-operative myocardial ischemia and periop­ erative myocardial infarction. Pre-operative identification of patients at risk of developing peri-operative myocardial ischae­ mia is often difficult or even impossible due to the inability of the patient to perform an exercise test. For those unable to perform physical exercise a system has recently been described combining transoesophageal echocardiography with simulta­ neous transoesophageal atrial pacing via the same probe to detect pacing-induced wall motion abnormalities, a sign of coronary artery disease. In a prospective study, 20 patients with clinically suspected coronary artery disease undergoing hip replacement were ex­ amined pre-operatively by transoesophageal stress echocardiog­ raphy. During the subsequent operation the incidence of intra­ operative ischaemia was evaluated again in all 20 patients by transoesophageal echocardiography. In eight of the 20 patients (40%) wall motion abnormalities could be induced by transoe­ sophageal stress echocardiography pre-operatively. Intra-oper­ ative wall motion abnormalities occurred in six of these eight patients. In two patients with wall motion abnormalities in­ duced by transoesophageal stress echocardiography no abnor­ malities occurred during surgery. However, in those in whom wall motion abnormalities did occur during operation they occurred in the same left ventricular segment as those initiated by stress echocardiography. None of the patients without pre­ operatively inducible wall motion abnormality developed them during surgery. No patient developed a myocardial infarction intra- or post-operatively. Thus, preoperative transoesophageal stress echocardiography is a valuable technique for the detec­ tion of patients who may develop ischaemic wall motion ab­ normalities during surgery. This is a useful method to identify

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patients who may be at risk, especially those who are not able to perform a treadmill exercise test.

Editorial Comment: Preoperative assessment of pa­ tients at risk for perioperative myocardial ischemia is difficult in those who are unable to perform physical exercise. Thallium-2 0 1 radionuclide perfusion imaging with dipyridamole is useful but this technique is not universally available, is expensive, and may be unpleas­ ant for the patient because of the side effects of headache and hypotension associated with dipyridamole. The au­ thors report the results of a new method of stress echo­ cardiography combining transesophageal echocardiog­ raphy with rapid atrial stimulation via the same probe to detect cardiac motion wall abnormalities associated with coronary artery disease. This prospective study of 20 patients demonstrates that this technique accurately identifies those at risk for intraoperative myocardial ischemia, especially those who are unable to perform a treadmill exercise test. Charles B. Brendler, M.D. The Effect of Desmopressin Acetate on Postoperative Hemorrhage in Patients Receiving Aspirin Therapy

Before Coronary Artery Bypass Operations

I. GRATZ, J. KOEHLER, D. OLSEN, M. AFSHAR, N. DECASTRO, P. M. SPAGNA, S. G. ABLAZA AND G. E. LARIJANI, Depart­

ments of Anesthesia and Thoracic Surgery. Medical College of Pennsylvania, Philadelphia, Pennsylvania

J. Thorac. Cardiovasc. Surg. , 1 04: 1417-1422, 1992 It has been suggested that desmopressin acetate has been effective in reducing hemorrhage after coronary artery bypass grafting in patients receiving aspirin before operation. We conducted a prospective, randomized, placebo-controlled, dou­ ble-blind trial to determine the effectiveness and safety of desmopressin in these patients. Sixty-five patients pretreated with aspirin within 7 days before their scheduled elective cor­ onary artery bypass grafting were randomized to receive des­ mopressin (0.3 µg/kg) or placebo after cessation of bypass and reversal of heparin with protamine. The demographic charac­ teristics and last dose of aspirin were similar in both groups. There was a significant reduction in postoperative blood loss noted between groups for both chest tube blood loss (833 ± 311 ml for the 1-desamino-8-D-arginine vasopressin [ desmopressin] group versus 1176 ± 674 ml for the placebo group; p = 0.016) and total blood loss (1215 ± 381 ml for the desmopressin group versus 1637 ± 761 ml for the placebo group; p = 0.0097). Despite the differences in blood loss between the two groups, the red cell transfusions were not significantly different, but the use of platelets was less in the desmopressin group and almost achieved statistical significance (p = 0.053). Neither was there a difference in the occurrence of thrombotic complications between groups. It appears that desmopressin in this specific subgroup of patients receiving preoperative aspirin is effective as a prophylactic agent for reduction of postsurgical hemor­ rhage. Editorial Comment: Desmopressin has been shown to

improve platelet function and reduce hemorrhage in a

variety of clinical disorders. It appears that the drug acts by increasing the concentration of von Willebrand factor, an important mediator of platelet adhesion. In

this study of patients undergoing coronary artery by­ pass surgery who were receiving aspirin preoperatively, administration of desmopressin intraoperatively 3 0 minutes after comp 1etion o f heparin reversal with pro­ tamine resulted in a significant decrease in blood loss compared to controls. Further studies are required but desmopressin may be useful in reducing surgical hem­ orrhage in patients in whom aspirin has not been dis­ continued preoperatively. Charles B . Brendler, M.D.

Preoperative Management of Sickle Cell Patients

R. N. GEORGES, J. C. McDONALD AND E. A. DEITCH, Depart­ ment of Surgery, Louisiana State University Medical Center, Shreveport, Louisiana

J. La. State Med. Soc., 144: 316-319, 1992 During a 12-year period, 59 patients with sickle cell disease underwent a total of 73 operative procedures. There was a total of 30 non-sickle-cell-related and 7 sickle-cell-related compli­ cations for an incidence of 41 % and 10% respectively. There were no deaths. When complications were compared between patients that were transfused and those not transfused, there was no difference in the incidence of sickle-cell-related compli­ cations with an 8% incidence for the non-transfused group and 10% for the transfused group. A higher incidence of non-sickle­ cell-related complications (46% versus 32%) was noted in the transfused group, with atelectasis being the most common complication (p = .29). The type of transfusion therapy did not influence morbidity, since the complication rates in the simple and exchange transfusion groups were similar. In conclusion, our data indicate that routine preoperative blood transfusion does not appear to be beneficial in the surgical sickle cell patient, since preoperative blood transfusions did not reduce the incidence of sickle-cell-related complications.

Editorial Comment: It is commonly believed that pa­ tients with sickle cell disease undergoing surgery should receive preoperative blood transfusions to reduce the level of sickle cell hemoglobin. In this study of 59 sickle cell patients undergoing surgery there were a total of 30 nonsickle cell related and 7 sickle cell related com­ plications and no deaths. Preoperative transfusion ther­ apy did not affect the incidence of sickle cell related or other complications, and the overall complication rate was similar to that reported in the literature. The au­ thors conclude from this study and from a review of the literature that routine blood transfusions are not man­ datory in surgical patients to prevent sickle cell crises. Charles B. Brendler, M.D.

Fentanyl: Clinical Use as Postoperative Analgesic-Ep­ idural/lntrathecal Route

J. A. GRASS, Department of Anesthesiology/Critical Care Med­

icine, Johns Hopkins University School of Medicine, Balti­ more, Maryland

J. Pain Symptom Manag., 7: 419-430, 1992 The administration of epidural and intrathecal opioids for the management of postoperative pain is well established. Fen­ tanyl, because of its greater lipophilicity, offers a number of

PERIO PERATl:VE CARE

advantages over morphine for epidural analgesia, including a lower incidence of side effects and reduced risk of delayed­ onset respiratory depression. The relatively short duration of action of epidural fentanyl makes this agent more ideally suited for continuous infusion or patient-controlled epidural analgesia (PCEA). The effective doses and adverse effects profile of epidural fentanyl are reasonably well understood. Because of the lack of spread through the cerebrospinal fluid (CSF) and hence the segmental nature of the analgesia achieved, location of epidural catheter placement is of paramount importance when this agent is used. Prolonged epidural infusion of fentanyl may result in high systemic concentrations not dissimilar to IV infusion, and, therefore, the greatest efficacy of epidural fen­ tanyl administration may be in combination with low concen­ trations of bupivacaine, an approach that achieves a synergistic effect. 2-Chloroprocaine has been shown to antagonize epidural fentanyl analgesia. Intrathecal fentanyl for postoperative an­ algesia is limited by its short duration of action with single­ bolus administration. The widespread international increase in the use of epidural fentanyl for postoperative analgesia prom­ ises further improvements and refinement in techniques.

E ditorial Comment: This is a comprehensive review of the use of fentanyl in postoperative pain managemento Fentanyl has a rapid onset of action, short overall du­ ration of action, low incidence of side effects and low risk of delayed respi:ratm."y depressiono The efficacy of epidural fentanyl is enhanced when combined with low concentrations of bupivacaine, allowing a reduction in the dose of fentanyl with a lower risk of systemic side effectso Thus, fentanyl is an extremely effective agent in postoperative epidural patient-controlled analgesia. Charles R Brendler, MoDo Common Peroneal Nerve Palsy Associated With Epi­ dural Analgesia

D. E. COHEN, B. VAN DUKER, S. SIEGEL AND T. P. KEON, Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, University of Pennsyl­ vania School of Medicine, Philadelphia, Pennsylvania

Anesth. Analg., 76: 429-431, 1993

No Abstract

E ditorial Comment: This is a case report of common peroneal nerve palsy associated with epidural anes­ thesiao The peroneal ne1·ve splits off from the sciatic nerve in the middle of the posterior aspect of the thigh, enters the popliteal space and traverses lateral to the head of the fibula en route to the anterior surface of the lego This injury was believed to result from a prolonged sensory block following epidural anesthesia, during which the patient lay with the left fibula inadvertently compressed against the hospital bed raiL The authors recommend that in patients with a persistent loss of sensation pressure points be checked fr equently and special attention be given to position changes during this periodo In addition, the concentration of local anesthetic, which may perpetuate a sensory block, should be de­ creased until paresthesia of the lower extremities has been eliminated. Charles R Brendler, M.Do

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A Randomized, Double-Blind Evaluation of Ketorolac Tromethamine for Postoperative Analgesia in Ambu­ latory Surgery Patients

H. Y. WONG, R. L. CARPENTER, D. J. KOPACZ, R. J. FRAGEN, G. THOMPSON, T. J. MANEATIS AND L. J. BYNUM, Depart­ ment of Anesthesia, Northwestern Un iversity Medical School and Northwestern Memorial Hospital, Chicago, Illinois; De­ partment of Anesthesiology, Virginia Mason Clinic, Seat­ tle, Washington, and Syntex Laboratories, Inc., Palo Alto, California Anesthesiology, 78: 6-14, 1993

Background: Given the trend toward early discharge of pa­ tients after surgery and the inherent adverse effects of opioid analgesics, we compared a new nonsteroidal antiinflammatory drug, ketorolac tromethamine, given intravenously (iv) and then orally, with two commonly prescribed opioid analgesics in ambulatory patients for up to 1 week after surgery. Methods: In this study incorporating a double-blind, multi­ dose design, 221 patients who had moderate or severe pain after surgery were randomized to one of three treatment groups: group K30 received 30 mg iv ketorolac twice, then 10 mg iv every 30 min as required to control pain, up to six doses, followed by 10 mg oral ketorolac every 4-6 h; group F50 received 50 µg iv fentanyl at the same time intervals as in group K30, followed by 60 mg codeine plus 600 mg acetaminophen (C + A) orally every 4-6 h; and group FlO received the same combina­ tion as did group F50, but only 10 µg fentanyl per dose. Results: Compared with 50 µg fentanyl iv, 30 mg iv ketorolac provided delayed but otherwise equivalent analgesic effects and was associated with similar side effects. Compared with C + A, 10 mg oral ketorolac was associated with a lower incidence of nausea and somnolence and earlier return of bowel function but not better pain relief, drug tolerability, quality of life, or psychologic well-being. Conclusions: Ketorolac, when used in an iv and then oral sequence, is a safe and effective analgesic in the ambulatory surgery setting. It has a slower onset than fentanyl, but causes fewer side effects than C + A.

Editorial Comment: Ketorolac is a :relatively new non­ steroidal anti-inflammatory agent that is available in parenteral and oral forms o H has a :negligible effect on ventilation, hemodynamics and psychomotor control, making it an attractive alternative to opioid narcotics for outpatient surgery. This study demonsh·ates that keto:rofac given intravenously and then orally was as effective as intravenous fentanyl and more effective than a combination of oral codeine and acetaminophen in providing pain relief in ambulatory surgical patients o Ketorolac has a relatively slow onset of action bu.t over­ all it has been proved to be safe and effectiveo This study provides further evidence that ketorolac can reduce the use of opioid narcotics postoperatively. Charles R Brendler, MoD o

A Randomized, Double-Blind Pilot Study Examining the Use of Intravenous Ondansetron in the Prevention of Postoperative Nausea and Vomiting in Female Inpatients

R. McKENZIE, S. SHARIFI-AZAD, M. DERSHWITZ, R. MIGUEL, A. F. JOSLYN, B. TANTISIRA, F. ROSENBLUM, C. E. Rosow,

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J. B. DOWNS, J. R . B O WIE , K. S HEAHAN, S . ODELL, J. LESSIN, P . M . DIBIASE AND M . NATIONS, Departments of

Anesthesiology, University of Pittsburgh and Magee- Womens Hospital, Pittsburgh and Thomas Jefferson University, Phil­ adelphia, Pennsylvania; Department of Anaesthesia, Harvard Medical School and Department of Anesthesia, Massachusetts General Hospital, Boston, Massachusetts; Departments of Anesthesiology, University of South Florida College of Medi­ cine, and H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida, and Glaxo, Inc., Research Institute, Research Triangle Park, North Carolina

J. Clin Anesth., 5 : 30-36, 1993 Study Objective: To compare the efficacy and safety profiles of intravenous (IV) ondansetron (two 8 mg doses 8 hours apart) and a placebo when used in the prevention of postoperative nausea and emesis (vomiting or retching). Design: Randomized, double-blind, placebo-controlled, par­ allel, multicenter pilot study. Setting: Four university hospitals in the United States. Patients: Two hundred seven women scheduled to undergo inpatient surgical procedures during general anesthesia. Interviewing: Patients were randomized to receive, in a dou­ ble-blind fashion, either two 8 mg doses of IV ondansetron or a placebo. The first study drug dose was administered before induction of anesthesia; the second dose was given 8 hours later. Each study drug dose was admixed with normal saline to 20 ml and administered IV over 2 to 5 minutes. Vital signs were monitored immediately before and 1 minute after completion of the study drug infusion. Measurements and Main Results: For the 24-hour period following operation, 60% of the patients who received ondan­ setron and 26% of the patients who received the placebo were emesis-free (p < 0.001). Subanalyses based on patients' pre­ vious history of general anesthesia indicated that ondansetron was superior to the placebo in preventing emesis regardless of history [66% vs. 33% in patients who had never had general anesthesia or had no nausea or emesis following previous anes­ thesia (p = 0.001) and 50% vs. 17% in patients who had nausea or emesis following previous anesthesia (p = 0.005) ] . Ondan­ setron also was superior to the placebo for the prevention of nausea over the 24-hour study period regardless of anesthesia history. Ondansetron was generally well tolerated. The adverse event, vital sign, and clinical laboratory test profiles were similar to those for the placebo. No patient who received ondansetron had untoward changes in central nervous system function, including sedation. Conclusions: Prophylactic IV ondansetron appears to be safe and causes a significant reduction in the frequency and severity of postoperative nausea and emesis.

Editorial Comment: Ondansetron is a selective sero­ tonin type 3 antagonist that has been shown to be safe and effective when used in the prevention of chemother­ apy-induced nausea and vomiting. Several recent re­ ports have indicated that oral ondansetron may be ef­ fective in the prevention of postoperative nausea and vomiting, and intravenous ondansetron may be effective for its treatment. In this study of 207 women undergoing surgery while under general anesthesia those receiving 2, 8 mg. doses of ondansetron immediately before and 8 hours after the induction of anesthesia experienced sig­ nificantly less nausea and vomiting postoperatively. No specific side effects were associated with ondansetron.

In summary, this study contributes further evidence that ondansetron, administered prophylactically, signifi­ cantly reduces perioperative nausea and vomiting in patients undergoing general anesthesia. Charles B. Brendler, M.D. I-Fibrinogen Leg Scanning: Reassessment of Its Role for the Diagnosis of Venous Thrombosis in Post-Op­ erative Patients

125

A. W. A.

LENSING AND J. HIRSH , Hamilton Civic Hospital Research Centre, Hamilton, Ontario, Canada

Thromb. Haemost., 69: 2-7, 1993 Objective: To determine the reasons why 1251-fibrinogen leg scanning, a screening test which was reported to be very sen­ sitive for the detection of post-operative thrombosis, has shown poor sensitivity in contemporary studies. Study Identification: English-language reports were identi­ fied through a Medline computer search (1965-1991), Current Contents, and an extensive manual search of the bibliographies in identified articles. Study Selection: Studies in orthopedic or general surgical patients were reviewed that compared 1251-fibrinogen leg scan­ ning with venography in all patients (accuracy studies) or in patients in whom 1251-fibrinogen leg scanning became positive (positive predictive value studies). Data Extraction: A systematic appraisal of study design and specific descriptive information concerning the selection of patients. Results of Data Synthesis: Six of the 15 studies which com­ pared 1251-fibrinogen leg scanning with venography were level 1 studies (potential for bias minimized) and nine were classified as level 2 studies (potential for bias not minimized). In ortho­ paedic surgical patients, the pooled sensitivity of leg scanning for isolated calf vein thrombosis, for all venous thrombosis, and the pooled specificity were 55%, 45%, and 92% for the level 1 studies, respectively. These indices were 88%, 82%, and 79%, respectively for the level 2 studies (P <0.001). Only two (level 2) studies were found that evaluated the accuracy of leg scan­ ning for venous thrombosis in general surgical patients. Conclusion: We conclude that leg scanning is an insensitive method for the screening of post-operative venous thrombosis in orthopaedic patients. Our findings call into question the validity of the many studies (including meta-analyses) evalu­ ating prophylactic agents for venous thrombosis which used leg scanning as the only test for the assessment of efficacy.

Editorial Comment: Radioactive fibrinogen leg scan­ ning was developed 30 years ago and has become widely accepted as an accurate screening test for subclinical venous thrombosis. The authors critically reviewed lit­ erature evaluating the accuracy of fibrinogen leg scan­ ning for the diagnosis of deep venous thrombosis. Leg scanning was compared with venography in 15 studies, of which 6 were classified as having a minimal potential for bias. Leg scanning had a sensitivity of only 5 5 % for detecting calf vein thrombosis and only 45% for proxi­ mal vein thrombosis. The positive and negative predic­ tive values of leg scanning were 58% in the calf and 89% in the thigh. In addition, leg scanning has 3 other short­ comings that further limit its usefulness as a diagnostic screening tool: 1) it has low accuracy when performed over a site of extravasated blood, as in patients who

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have unde,.· gcm.e knee or hip su:rgery, the sensitivity of leg scanning is inversely proportional to the size of the thrombus and 3) the sensitivity of scanning is influ­ enced by the location of the thrombus. The authors con­ clude that fibrinogen leg scanning has se:rim.1.s limita­ tim.1s in assessing prophylactic deep ven.m1s thrombosis studies and that venog:raphy is the only proved reliable diagnostic test for evaluating the efficacy of deep venous thrombosis prophylaxis. Charles B. Brendler, M.D. Low Molecular Weight Versus Standard Heparin for Prevention of Venous Thromboemboli§m After Major Abdominal Surgery V. V.

KAKKAR, A. T. COHEN, R. A. EDMONSON , M. J. PHILLIPS, D. J. CO OPER, S. K. DAS, K. T. MAHER, R. M. SANDERSON, V. P. WARD AND S. KAKKAR, Thrombosis Re­

search Institute, and King's College School of Medicine and Dentistry, London, England

Lancet, 3 4 1 : 259-265, 1993 Low-molecular-weight heparin (LMWH) is effective in the prevention of postoperative venous thromboembolism but does it have the safety advantages over standard heparin (SH) that have been claimed? In a multicentre randomised trial in 3809 patients undergoing major abdominal surgery (1894 LMWH, 1915 SH) heparin was given preoperatively and continued for at least 5 postoperative days. Patients were assessed in the postoperative period and were followed up for at least 4 weeks, the emphasis being on safety. Major bleeding events occurred in 69 (3.6%) patients in the LMWH group and 91 (4.8%) patients in the SH group (relative risk 0.77, 95% confidence interval 0.56-1.04; p = 0.10). 93 indices of major bleeding were observed in the 69 LMWH patients and 141 in the SH patients. (p = 0.058). Severe bleeding was less frequent in the LMWH group (1.0% vs 1.9%; p = 0.02), as was wound haematoma (1.4% vs 2.7% ; p = 0.007). Bleeding episodes with LMWH were less likely to lead to further surgery to evacuate a haematoma or to control bleeding, and injection site bruising was also less common in the LMWH group. No significant differences were found in the efficacy of the two agents. Perioperative death rates were 3.3 % in the LMWH group and 2.5% in the SH group; pulmonary emboli were detected in 0. 7% and 0. 7% ; and deep-vein thrombosis was diagnosed in 0.6% of patients in each group. Follow-up was done on 91 % of 3699 evaluable patients. There were 19 further deaths (10 LMWH, 9 SH group) and 25 patients with throm­ boembolic complications (15 and Of the 3 patients with fatal pulmonary emboli during follow-up 2 had received LMWH and 1 SH. The two drugs were of similar efficacy. The primary end point, the frequency of major bleeding, showed a 23 % reduction in the LMWH group, but this difference was not significant. The secondary safety end points revealed that LMWH was significantly better than SH. Fatal pulmonary embolism occurs rarely (0.09%) following discharge from hospital so the cost benefit ratio would not justify prolonged prophylaxis in this setting. E ditorial Comment: This multicenter prospective study of more than 3 ,800 patients demonstrated that low molecular weight heparin is as effective as standard calcium heparin preparations. Furthermore, the trial

§howed that patients treated with low molecufa:r weight heparin had a 23% reduction in major bleeding, fewer objective indexes of major bleeding postoperatively, fewer wound hematomas and fewe:r operations to evac­ uate hematomas o:r control bleeding, The authmrs con­ clude that "no individual surgeon , however busy, will be in a position to :recognize the success of p:rophyiacti.c action (for DVT) , yet he or she will be remfoded of failures when bleeding complications develop, Now that clinicians have, in LMWH, an effective p:rophylactic regimen which is also safe and simple fo:r nurses to use they should ensure that all high-:risk patients are pro­ tected,'' Their recommendation is sound and is clearly substantiated by all of the available data. Charles B . Brendler, M.D. Antimicrobial Prophylaxis for Surgical W mmds: Guide­ lines fo:r Clinical Care C. P. PAGE, MCMANUS,

J. M. A. BOHNEN, J. R. FLETCHER, A. T. J. S. SoLOMKIN AND D. H. WITTMANN, Depart­

ments of Surgery, University of Texas Health Science Center, San Antonio and Microbiology Branch, United States Army Institute of Surgical Research, Fort Sam Houston, Texas; University of Toronto, Toronto, Ontario, Canada; University of South Alabama, Mobile, Alabama; University of Cincinnati College of Medicine, Cincinnati, and Medical College of Wisconsin, Milwaukee, Wisconsin

Arch. Surg., 128: 79-88, 1993

Prophylactic administration of antibiotics can decrease post­ operative morbidity, shorten hospitalization, and reduce the overall costs attributable to infections. Principles of prophy­ laxis include providing effective levels of antibiotics in the decisive interval, and, in most instances, limiting the course to intraoperative coverage only. Use in The National Research Council clean contaminated operations is appropriate and, in many instances, has been proven beneficial. Antibiotic prophy­ laxis is also indicated for clean operations, such as those in­ volved with insertion of prosthetic devices, that are associated with low infection risk and high morbidity. Extension of anti­ biotic prophylaxis to other categories of clean wounds should be limited to patients with two or more risk factors established by criteria in the study of the efficacy of nosocomial infection control (SENIC) because the baseline infection rate in these patients is high enough to justify their use. Cefazolin cefoxitin when anaerobic coverage is necessary) remains the mainstay of prophylactic therapy. Selection of an alternate agent should be based on specific contraindications, local in­ fection control surveillance data, and the results of clinical trials. Newer criteria for determining the risk of "site infection" (wound and intracavitary) are in evolution and may lead to modification of these recommendations over the next several years.

Editorial Comment: This article summarizes current guidelines for surgical antimicrobial prophylaxis. The authors review factors associated with an increased risk of postoperative infection, the incidence of infection by wound category and the toxicities of antibiotics com­ monly used for prophylaxis, and they provide site-spe­ cific recommendations for prophylactic antibiotic agents. The article cannot be summarized adequately in th.is comment, and it is recommended that it be :read and

1348

saved by all urologists.

PERIOPERATIVE CARE

Charles B. Brendler, M.D.

Postoperative Intra-Abdominal Sepsis Requiring Reop­ eration: Value of a Predictive Index

J. F. PUSAJ6, E. BUMASCHNY, G. R. DOGLIO, M. R. CHERJOVSKY, A. I. LIPINSZKI, M. s. HERNANDEZ AND M. A. EGURROLA, General Surgery Service and Intensive Care Unit, Hospital Israelita "Ezrah " and Department of Surgery, Uni­ versity of Buenos Aires, Buenos Aires, Argentina

Arch. Surg., 1 2 8 : 218-223, 1993 In this study we analyze the results of the use of a predictive index to decide whether to perform abdominal reoperation in the event of septic complications. During a 5-year period, a population of 542 critically ill patients received major abdomi­ nal surgery. Patients were divided into two groups: (1) the control group, for which the decision to reoperate was made routinely, based on clinical consensus of the medical team; and (2) the Abdominal Reoperation Predictive Index group, for which the decision to reoperate was made with the help of a mathematical index involving eight mainly clinical variables. The use of Abdominal Reoperation Predictive Index enabled mortality among patients undergoing reoperation to be lowered, the time elapsing between the first operation and relaparotomy to be reduced, and the length of stay in the intensive care unit to be shortened. We conclude that the systematic application of an index, without disregarding clinical judgment, allows the quality of attention to be improved, cost to be lowered, and the level of conflicts generated by the difficult decision to perform reoperation to be curtailed.

Editorial Comment: The authors have developed an abdominal reoperation predictive index to decide whether reoperation for intra-abdominal sepsis is re­ quired. This index is based on 8 variables: 1) emergency surgery at primary operation, 2) respiratory failure, 3) renal failure, 4) ileus at more than 72 hours after sur­ gery, 5) abdominal pain at more than 48 hours after surgery, 6) wound infection, 7) alteration in conscious­ ness and 8) symptoms appearing after postoperative day 4. They have assigned a score to each of these variables from which this predictive index was determined. Ap­ plication of the index, in combination with clinical judg­ ment, resulted in an overall decreased mortality, less time between first and subsequent operations, and de­ creased length of stay in the intensive care unit. The authors recognize that such an index cannot replace clinical judgment and expertise but it may be a useful adjunct when deciding whether to reoperate. Charles B. Brendler, M.D. Management of Postoperative Intra-Abdominal Ab­ scesses by Routine Percutaneous Drainage

T. R. MCLEAN, K. SIMMONS AND L. G. SVENSSON, Cora and Webb Madding Department of Surgery, and Department of Radiology, The Baylor College of Medicine, Houston, Texas

Surg., Gynec. & Obst., 176: 167-177, 1993 Permission to Publish Abstract Not Granted

Editorial Comment: This article presents clear guide-

lines for percutaneous drainage of postoperative intra­ abdominal abscesses. Although several studies from the radiology literature have suggested that percutaneous drainage is appropriate first line treatment for all intra­ abdominal abscesses, this study found that only a third of the patients were successfully managed with percu­ taneous drainage alone. The authors establish guidelines for patients likely to benefit from percutaneous drain­ age and conclude that those in whom an anastomotic dehiscence is a possibility should be managed primarily with open surgery. Since most intraperitoneal abscesses encountered by urologists are likely to occur in associ­ ation with an intestinal and/or urinary anastomosis, they may be managed best by primary surgical drainage. Charles B . Brendler, M.D. Postoperative Feeding: Liquid Versus Solid Fuel

M. FELDMAN, Medical Service (1 1 1), Dallas Veterans Admin­ istration Medical Center, Dallas, Texas

Gastroenterology, 1 04: 324-330, 1993 No Abstract

Editorial Comment: Traditional surgical teaching dic­ tates that patients should be started on a liquid diet after abdominal surgery and gradually advanced to a regular diet to reduce the risk of postoperative gastrointestinal complications, This study clearly challenges that dogma. In this series 1 7 1 patients who underwent gastrointes­ tinal surgery were randomized to receive either a tra­ ditional liquid diet or solid food immediately after the nasogastric tube was removed. There was no difference in the rate of gastrointestinal complications or length of hospitalization. The authors conclude that gradual pro­ gression of diet postoperatively is unnecessary, and im­ mediate institution of a regular diet is not associated with an increased risk of gastrointestinal complications, Charles B. Brendler, M.D. The PROEF Diet-A New Postoperative Regimen for Oral Early Feeding

L. WEINSTEIN, P. L. DYNE AND N. B. DUERBECK, Departments of Obstetrics and Gynecology, Medical College of Ohio, To­ ledo, Ohio, and University of Arizona, Tucson, Arizona

Amer. J. Obst. Gynec., 1 6 8 : 128-131, 1993 OBJECTIVE: The purpose of this study was to determine if immediate postoperative feeding of a new oral elemental diet (PROEF diet) would be tolerated by patients and to determine its effect on gastrointestinal function after cesarean section. STUDY DESIGN: One hundred eighteen patients undergo­ ing cesarean section were randomly assigned by a computer­ generated list of numbers to receive either the PROEF diet (60 patients) or routine postoperative dietary management (58 patients). Gastrointestinal morbidity was analyzed by an in­ dependent-samples t test. RESULTS: The PROEF diet group had a more rapid return of normal bowel sounds, 10.3 versus 14.5 hours (p = 0.001), and earlier acceptance of a regular diet, 2.0 versus 2.3 days (p = 0.008) . CONCLUSION: The PROEF diet was well tolerated in ce-

PERWPERATIVE CARE

sarean section patients with no increase in gastrointestinal morbidity when compared with a control group of patients. This dispels the classic teaching that postoperative patients may not have oral intake until the return of normal bowel function. Further study is necessary to support the theoretic benefits that may accrue from early feeding of an elemental diet. Editorial Comment: The autho:rs demonstrate that early enteral feeding of an elemental diet is well toler­ ated with no increase in gastrointestinal morbidity. This study, like the one by Feldman (see preceding comment) , challenges traditional dogma, suggesting that it is com­ pletely safe to begin. at least an elemental diet immedi­ ately following abdominal surgery and that resumption of a regular diet need not be preceded by clear and full liquid diets. Charles B . Brendler, M.D.

Experience With. Ambulatory Preoperative Bowel Prep­ aration at The Johns Hopkins Hospital J . C. HANDELSMAN, S . ZEILER, J . COLEMAN, W. DOOLEY AND J. M. WALRATH, Departments of Surgery, and Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine and Hospital, Baltimore, Maryland Arch. Surg. , 1 2 8 : 441-444, 1993 A transition to ambulatory preoperative antibiotic bowel preparation was carried out. The protocol included a liquid diet for 40 hours preceding surgery and coordination of purging with buffered oral saline laxative, 45 mL containing 8 g sodium phosphate and 22 g sodium biphosphate (Fleet Phospho-Soda, C. B. Fleet Co, Lynchburg, Va) and bisacodyl preparation with an oral erythromycin base-neomycin routine. Enemas were omitted. Personnel in the preoperative evaluation center had the responsibility of instructing patients, distributing directions and drugs, and reviewing for compliance and possible problems during the preoperative period. All patients scheduled for any of a variety of gastrointestinal procedures, as well as some other complex operations, were included in this study. Follow-up data were obtained. Surgeons' comments regarding efficacy were highly favorable. In only five cases was there comment regard­ ing liquid stool, and this was no impediment to surgery. This incidence was comparable with that of the inpatient experience, as was the spectrum of p ostoperative complications. Transfer of responsibility to the department proceeded with ease. Results were entirely comparable with those of the former inpatient experience. Editorial Comment: This :report demonstrates that preope:rative bowel preparation can be accomplished safely on an outpatient basis. In this study of 1 00 pa­ tients bowel preparation was accomplished on an am­ bulatory basis with minimal complications. Although. the article does not address intraoperative intestinal bacte­ rial colony counts or p ostoperative morbidity, previous

studies have shown that ambulatory bowel preparation is not associated with an increased risk of infection. Therefore, it is no longer necessary to hospitalize pa­ tients preoperatively for routine bowel preparation re­ gardless of the surgical procedure being performed. Charles B. Brendler, M.D.

How Conservatively Can Obstruction be Treated

1349 Smal.1 Bowel

D. SEROR, E. FEIGIN, A. SzoLD, T. M. ALLWEIS, M. CARMON, S. NISSAN AND H . R. FREUND, Department of Surgery, Hadassah University Hospital Mount Scopus and Hebrew University-Hadassah Medical School, Jerusalem, Israel Amer. J. Surg., 1 6 5 : 121-126, 1993 Although postoperative adhesion ileus is the most common cause of small bowel obstruction in adults, its management remains controversial. We retrospectively studied 297 admis­ sion of 227 patients over a period of 14 years to evaluate our conservative approach in managing adhesion ileus. We found that nonoperative therapy of up to 5 days' duration can be used safely for the majority of patients who present with postoper­ ative intestinal obstruction, including. those with complete ob­ struction. In those patients who . responded to conservative treatment, the obstruction resolved within a mean of 22 hours and a maximum of 5 days. A trial of more than 5 days' duration proved ineffective. The conservative approach resulted in a 73 % resolution of obstruction with no significant increase in mortality or in the rate of strangulated bowel. Editorial Comment: This interesting study demon­ strates that most cases of postoperative small bowel obstruction can. be managed conservatively. However, obstruction more than 5 days in d1uaticm is unlikely to respond to further conservative management and should, therefore, be treated sm·gicali.y. Charles B . B:rendle:r, M.D.

Preoperative Intensive C are Unit Consultations: Accu. :ra.te and E ffective

0

A. J. VARON , J. A. HUDSON-CIVETTA, J. M. CIVETTA AND M. Yu, Departments of Surgery and Anesthesiology, University of Miami School of Medicine, Miami, Florida Crit. Care Med., 2 1 : 234-239, 1993 Objectives: To determine if a structured preoperative ICU consultation would correctly assign patients to preoperative invasive monitoring, postoperative ICU care, or recovery room care, and to compare morbidity, rnortality, and resource utili­ zation among all groups. Design: Prospective, observational Setting: A university hospital. Patients: A total of 475 patients who were referred preoper­ atively by surgeons for ICU consultation and were evaluated by ICU physicians. Interventions: Patients assessed to have clinical evidence of cardiovascular compromise were admitted preoperatively to the ICU for invasive hemodynamic monitoring and optimization. Patients without such evidence, but who were to undergo major operations or had anticipated major fluid replacement were independently selected for invasive monitoring by anesthesiol­ ogists. Patients who developed physiologic instability or became unstable due to hemorrhage also underwent invasive monitor­ ing. Nonmonitored patients who remained stable were given postoperative ICU care or went to the recovery room based on an assessment by the surgeon and anesthesiologist at the end of the operation. Measurements and Main Results: Of 8,916 elective surgical cases, ICU physicians were consulted in 475 (5.3 % ) patients

1350

URINARY TRACT INFECTION

preoperatively. Sixty-seven patients were admitted preopera­ tively to the ICU for invasive hemodynamic monitoring and optimization; 60 patients had surgery (0. 7% of elective cases, 12.6% of ICU consultations). Patients selected for ICU preop­ erative monitoring were older than nonmonitored patients and had higher numbers of cardiovascular and total risk factors than any other group. They had higher Acute Physiology and Chronic Health Evaluation (APACHE II) scores, higher Ther­ apeutic Intervention Scoring System (TISS) points, a higher number of complications, and longer ICU stays than nonmon­ itored postoperative ICU patients. In addition, they had a higher number of complications than nonmonitored recovery room patients. APACHE II scores, TISS points, number of complications, and ICU days in the preoperative ICU admission group were not increased when compared with all other moni­ tored patients. Neither hospital days nor total hospital charges were increased when compared with the other elective ICU patients. Patients selected for ICU preoperative monitoring who underwent surgery had an 11.7% mortality rate and ac­ counted for four of five cardiovascular-related deaths. Conclusions: A small number of high-risk patients can be selected for preoperative monitoring on the basis of clinical assessment without increasing ICU stay or hospital bills. A structured preoperative consultation correctly identifies those patients who need monitoring and ICU care, but does not overutilize scarce and expensive ICU beds.

Editorial Comment: In this study patients with evi­ dence of cardiovascular disease were hospitalized pre­ operatively and evaluated in the intensive care unit to determine the risk for surgery and need for intensive care postoperatively. Overall, 5.3% of the patients underwent intensive care evaluation, of whom 12.6% underwent preoperative hemodynamic monitoring and optimization. The authors conclude that preoperative consultation in the intensive care unit correctly identi­ fies patients who will need postoperative monitoring and intensive care, and may result in more efficient assignment of beds. Charles B. Brendler, M.D. Does Ranitidine Provide Protection Against Acid Gas­ troesophageal Reflux?

D. VERBESSEM, F. CAMU AND A. VAN DE VELDE, Department of Anaesthesiology, Flemish Free University of Brussels Med­ ical Center, Brussels, Belgium Canad. J. Anaesth., 40: 4-9, 1993 Continuous gastroesophageal pH monitoring was used to evaluate the effect of ranitidine on gastroesophageal reflux (GOR) in 60 patients scheduled for elective non-gastrointes­ tinal abdominal or gynaecological surgery. The patients were randomly assigned to receive a single dose of ranitidine 50 mg either iv (RANIV group) or in (RANIM group) or a placebo iv (PLAC group) 90 min before surgery. The pH was measured continuously for six hours in the lower oesophagus using a flexible calibrated glass electrode. A pH < 4.0 was chosen as the boundary for defining occurrence of acid GOR. Both rani­ tidine treatments reduced the total number of acid reflux episodes and the global reflux index (P < 0.05). The duration of the acid reflux episodes (sum of refluxes) and the number of acid reflux episodes longer than five minutes were markedly decreased by ranitidine but the mean duration of the reflux

episodes was unaffected. The pH values at induction, intuba­ tion, surgical incision and extubation were similar in the PLAC and RANIV groups but more acid than in the RANIM group. The mean pH of reflux episodes was less acid in both ranitidine groups that in the PLAC group (P < 0.05). Also the number of very acid refluxes (pH < 2.5) decreased with ranitidine (P < 0.05). Intramuscular and intravenous administration of raniti­ dine provide protection against gastroesophageal reflux, with shorter duration of reflux episodes occurring in the intramus­ cular group. Regardless of the administration of ranitidine, protection against gastroesophageal reflux is incomplete; the frequency of reflux episodes is reduced but not eliminated.

E ditorial Comment: Pulmonary aspiration of gastric contents remains a major risk of perioperative morbid­ ity and mortality in anesthesia. Ranitidine is a histamine receptor antagonist that inhibits basal and nocturnal gastric acid secretion. The drug is 4 to 9 times more potent than cimetidine with a longer duration of action and fewer side effects. In this study intravenous admin­ istration of a single dose of ranitidine 90 minutes before induction of general anesthesia significantly reduced the number of acid reflux episodes longer than 5 minutes but it did not affect mean duration of the reflux episodes. In summary, prophylactic administration of a single dose of ranitidine before administration of anesthesia provided incomplete protection against gastroesopha­ geal reflux, decreasing the frequency but not eliminat­ ing reflux episodes. Charles B . Brendler, M.D. URINARY TRACT INFECTION

Fleroxacin Versus Norfloxacin in the Treatment of Uri­ nary Tract Infections: A Multicenter, Double-Blind, Prospective, Randomized, Comparative Study K. PUMMER, Division of Urology, University Hospital, Graz, Austria

Amer. J. Med., suppl. 3A, 94: 108S-113S, 1993

In a multicenter, double-blind, prospective, randomized, comparative study, fleroxacin, 400 mg once daily orally, was compared with norfloxacin, 400 mg twice daily orally. Each drug was given for 10 days to study efficacy and safety in the treatment of uncomplicated, recurrent, or complicated urinary tract infection (UTI). A total of 587 patients from 22 centers were enrolled and randomly assigned to fleroxacin (n = 291) or norfloxacin (n = 296). Of these, 163 patients in each group were included in the efficacy analysis, and 287 in the fleroxacin group and 292 in the norfloxacin group were included in the safety analysis. There was no difference between the two groups in terms of bacteriologic or clinical efficacy, with cure rates for each diagnostic subgroup of 93-100% in the fleroxacin group and 91-96% in the norfloxacin group. Superinfection, reinfec­ tion, or relapse, as well as development of resistance to the administered drugs, were infrequent and comparable in the two groups. Adverse events were documented in a significantly higher number of patients treated with fleroxacin and involved mainly the digestive system, the central nervous system, and the skin. However, >90% of such adverse events were judged as mild or moderate in severity and did not lead to premature termination of treatment. Fleroxacin exhibited a clinical and