Abdominal Surgery Patients Research Articles

Opioid-sparing properties of intranasal ketorolac: a pooled analysis of patients experiencing moderate-to-severe acute pain

Ketorolac is a nonopioid mixed COX1/2 inhibitor used for short-term (up to 5 days) management of moderate-to-severe acute pain. An intranasal (IN) formulation of ketorolac is in development as a self-administered alternative to injectable ketorolac and opioids for pain management. The pharmacokinetics of IN ketorolac are similar to those of ketorolac administered intramuscularly. The efficacy and tolerability of IN ketorolac were assessed in phase 2/3 clinical trials in 705 patients (men and women, ≥18 yr). Abdominal and orthopedic surgery models were used to assess IN ketorolac efficacy in managing moderate-to-severe acute pain. Patients received IN ketorolac (31.5 mg) (n=455) or placebo (n=250) 3 or 4 times a day for up to 5 days. Statistically significantly greater reductions in the summed pain intensity difference over 48 hr occurred in patients receiving IN ketorolac compared to placebo (P<0.05). The most common adverse events in the IN ketorolac group were transient nasal discomfort (15% vs. 2% placebo) and rhinalgia (12% vs <1% placebo). Most patients received concurrent opioid analgesics for the first 48 hr. Morphine use (mg) was calculated by adding all PCA morphine and morphine equivalents (using American Pain Society guidelines for other analgesic medications). Patients in the IN ketorolac group used 34% less morphine over 48 hours after surgery compared to the placebo group (P<0.001). In the first 8 hr after surgery, patients receiving IN ketorolac undergoing orthopedic surgery had greater decreases in opioid use relative to placebo than did abdominal surgery patients. Reductions in opioid use were similar when stratified by age and sex. Efficacy in this clinical model indicates that IN ketorolac provides a noninjection parenteral option for management of acute moderate-to-severe pain that may be particularly useful for ambulatory patients, particularly where avoidance of, or reductions in, opioid use are desirable. (Supported by ROXRO PHARMA). Ketorolac is a nonopioid mixed COX1/2 inhibitor used for short-term (up to 5 days) management of moderate-to-severe acute pain. An intranasal (IN) formulation of ketorolac is in development as a self-administered alternative to injectable ketorolac and opioids for pain management. The pharmacokinetics of IN ketorolac are similar to those of ketorolac administered intramuscularly. The efficacy and tolerability of IN ketorolac were assessed in phase 2/3 clinical trials in 705 patients (men and women, ≥18 yr). Abdominal and orthopedic surgery models were used to assess IN ketorolac efficacy in managing moderate-to-severe acute pain. Patients received IN ketorolac (31.5 mg) (n=455) or placebo (n=250) 3 or 4 times a day for up to 5 days. Statistically significantly greater reductions in the summed pain intensity difference over 48 hr occurred in patients receiving IN ketorolac compared to placebo (P<0.05). The most common adverse events in the IN ketorolac group were transient nasal discomfort (15% vs. 2% placebo) and rhinalgia (12% vs <1% placebo). Most patients received concurrent opioid analgesics for the first 48 hr. Morphine use (mg) was calculated by adding all PCA morphine and morphine equivalents (using American Pain Society guidelines for other analgesic medications). Patients in the IN ketorolac group used 34% less morphine over 48 hours after surgery compared to the placebo group (P<0.001). In the first 8 hr after surgery, patients receiving IN ketorolac undergoing orthopedic surgery had greater decreases in opioid use relative to placebo than did abdominal surgery patients. Reductions in opioid use were similar when stratified by age and sex. Efficacy in this clinical model indicates that IN ketorolac provides a noninjection parenteral option for management of acute moderate-to-severe pain that may be particularly useful for ambulatory patients, particularly where avoidance of, or reductions in, opioid use are desirable. (Supported by ROXRO PHARMA).

Need to improve thromboprophylaxis across the continuum of care for surgical patients

Prophylaxis for venous thromboembolism (VTE) is underused following major surgery and frequently stopped at hospital discharge despite short stays and high VTE risk for several weeks postsurgery. We evaluated inpatient and postdischarge prophylaxis in patients who underwent major abdominal or orthopedic surgery. Patient records were assessed for anticoagulant use by cross-matching data from the Premier's Perspective discharge database with the i3/Ingenix LabRx outpatient and inpatient database from January 2005 to December 2007. Abdominal or orthopedic surgery patients at risk of VTE according to the 2004 American College of Chest Physicians guidelines and with no contraindications to anticoagulation were included. A total of 14,009 eligible surgical discharges were analyzed. Only 27.9% of the 10,698 abdominal surgery patients received anticoagulation in hospital. Most inpatients received unfractionated heparin (12.3% of the total abdominal surgery population) or enoxaparin (11.8%). Of the 3311 orthopedic surgery patients, 91.1% received in-hospital anticoagulation. Similar proportions of patients received enoxaparin (32.1%), warfarin (31.1%), or other agents (28.0%). Only 1.2% of abdominal surgery patients had an anticoagulant prescription filled 30 days postdischarge. Although orthopedic surgery outpatients had higher anticoagulation rates, only 54.4% had filled a prescription 30 days postdischarge with 31.1% receiving warfarin, 18.5% receiving enoxaparin, and 4.8% receiving other anticoagulants. The higher prophylaxis rate in orthopedic patients may reflect the high VTE risk in orthopedic surgery patients and increased awareness among orthopedic surgeons. This real-world study highlights the underuse of thromboprophylaxis in hospitalized surgical patients, especially following abdominal surgery. Furthermore, a considerable proportion of these patients do not receive postdischarge anticoagulation despite guideline recommendations. Further efforts are needed to improve anticoagulant use, particularly in the outpatient setting.

Surgery-Induced Inflammation in Relation to Age, Muscle Endurance, and Self-Perceived Fatigue

Elective abdominal surgery can be considered as a model for an important acute inflammatory trigger in human participants. The aim of the study was to explore the effect of surgery-induced inflammation on muscle strength, endurance, and self-perceived fatigue and its relation with age. Sixty-six elective abdominal surgery patients aged 24-91 years were assessed before and at the second and fourth day after surgical intervention. Outcome parameters were grip strength, muscle endurance, fatigue subscale of the Profile of Mood State and visual analog scale for pain, and the circulating inflammatory mediators C-reactive protein, interleukin (IL)-6, and tumor necrosis factor-alpha (TNF-alpha). All parameters worsened postoperatively (p < .01) and remained significantly (p < .05) worse until the fourth day postsurgery, except for TNF-alpha (no significant change). Older age was related to higher surgery-induced IL-6 levels at the second (p < .05) and fourth postoperative (p < .01) day and to worse self-perceived fatigue and muscle endurance (both p < .05) at the fourth postoperative day. Higher pain levels at the second day following surgery was related to more self-perceived fatigue (p < .05). Worsening muscle endurance following surgery was significantly related to higher IL-6 release following surgery (p < .01) and self-perceived fatigue (p < .05) at the fourth day following the intervention. Age and surgery-induced increase in circulating IL-6 at Day 4 postsurgery was highest in patients showing both worsened muscle endurance and self-perceived fatigue (p < .05). Surgery-induced inflammation is related to reduced muscle endurance and the sensation of fatigue. Elderly patients suffer from a higher impact of surgery on muscle endurance.

Effect on immune indices of preoperative intravenous glutamine dipeptide supplementation in malnourished abdominal surgery patients in the preoperative and postoperative periods

Objective To determine if parenteral glutamine dipeptide supplementation given only in the preoperative period in malnourished patients after gastrointestinal surgery would sustain its effects into the first postoperative week, as shown by immune indices. Methods A prospective randomized study on malnourished adult patients for abdominal surgery was done where one group ( n = 17) received preoperative glutamine supplementation (0.3 g · kg −1 · d −1) for 5 d and the other ( n = 17) had none. Both received isocaloric (30 kcal · kg −1 · d −1) and isonitrogenous (1.5 g · kg −1 · d −1) nutrition. Outcomes were 1) immune indices on admission (day 1), the day before surgery (day 2), and the seventh postoperative day (day 3); and 2) clinical outcomes were infection, wound complication, days in the intensive care unit, and mortality. Statistical tests were repeated samples analysis of variance, Friedman's test, Wilcoxon's test, and t test for individual comparison. Results The glutamine-supplemented group showed an increase in total white blood cells (from 8700 on day to 11 080 on day 2, P = 0.026), granulocytes (from 6177 on day 1 to 8568 on day 2, P = 0.039), and lymphocytes (from 1516 on day 1 to 1747 on day 2, P = 0.049). Significant decreases in glutamine-supplemented group values from day 2 to day 3 occurred in granulocytes, lymphocytes, and CD8, CD22, and CD19 cells. Clinical outcome was similar in both groups. Intake was adequate in both groups (preoperative 85% versus postoperative 82% computed) and the mean glutamine delivered was 18 g/d. Conclusion Parenteral glutamine supplementation in the preoperative period resulted in increased white blood cell, granulocyte, and lymphocyte counts, which was not sustained in the first week of the postoperative period, when supplementation was discontinued before surgery.

Dérivation portocave intrahépatique transjugulaire avant chirurgie hépatique en cas de cirrhose compliquée d’hypertension portale

Major abdominal surgery may be contraindicated in patients with cirrhosis because of the high risk of intraoperative bleeding and postoperative decompensation. Careful preparation of these patients is essential, aimed especially at reducing portal hypertension. We report the case of a patient with cirrhosis complicated by hepatocellular carcinoma, whose portal hypertension manifested almost exclusively by reanastomosis from the umbilical vein. A transjugular intrahepatic portosystemic shunt (TIPS) was placed before surgery to prepare the patient for hepatic resection. In addition to the singularity of the presentation of portal hypertension, this case prompts us to consider neoadjuvant TIPS as a means of preparing these at-risk patients for major abdominal surgery.

Does Prior Abdominal Surgery Influence Conversion Rates and Outcomes of Laparoscopic Right Colectomy in Patients with Neoplasia?

The study investigated the impact of prior abdominal surgery on conversions and outcomes of laparoscopic right colectomy. A consecutive series of 414 patients with cancer or adenomas who underwent a laparoscopic right colectomy from March 1996 to November 2006 were studied for surgical conversions and outcomes. Conversion was defined as an incision length > 7 cm. Patients with prior abdominal surgery (n = 191) were compared with patients with no prior abdominal surgery (n = 223), and showed no significant differences in age, ASA classification, length of stay, operative time, blood loss, harvested nodes, tumor size, and specimen length. Significantly more wound infections occurred in the prior abdominal surgery group (22 vs.12, P = 0.023). Body mass index > 30 showed a three-fold increased risk of conversion. Fifteen percent of the no prior abdominal surgery patients and 17 percent of the prior abdominal surgery patients were converted (P > 0.05). Conversion was associated with a longer mean length of stay (8.8 days) relative to laparoscopically completed cases (6.3 days) regardless of prior abdominal surgery history (P < 0.0001). Laparoscopic right colectomy for neoplasia was not associated with a higher conversion rate or morbidity in patients with prior abdominal surgery. Prior abdominal surgery is not a contraindication to laparoscopic right colectomy.

Effects of levosimendan on indocyanine green plasma disappearance rate and the gastric mucosal–arterial pCO2 gradient in abdominal aortic aneurysm surgery

Levosimendan has a dual mechanism of action: it improves myocardial contractility and causes vasodilatation without increasing myocardial oxygen demand. In a laboratory setting, it selectively increases gastric mucosal oxygenation in particular and splanchnic perfusion in general. The aim of our study was to describe the effects of levosimendan on systemic and splanchnic circulation during and after abdominal aortic surgery. Twenty abdominal aortic aneurysm surgery patients were randomized to receive either levosimendan (n=10) or placebo (n=10) in a double-blinded manner. Both the mode of anaesthesia and the surgical procedures were performed according to the local guidelines. Automatic gas tonometry was used to measure the gastric mucosal partial pressure of carbon dioxide. Systemic indocyanine green clearance plasma disappearance rate (ICG-PDR) was used to estimate the total splanchnic blood flow. The immediate post-operative recovery was uneventful in the two groups with a comparable, overnight length of stay in the intensive care unit. Cumulative doses of additional vasoactive drugs were comparable between the groups, with a tendency towards a higher cumulative dose of noradrenaline in the levosimendan group. After aortic clamping, the cardiac index was higher [4(3.8-4.7) l/min/m(2) vs. 2.6(2.3-3.6) l/min/m(2); P<0.05] and the gastric mucosal-arterial pCO(2) gradient was lower in levosimendan-treated patients [0.9(0.6-1.2) kPa vs. 1.7(1.2-2.1) kPa; (P<0.05)]. However, the total splanchnic blood flow, estimated by ICG-PDR, was comparable [29(21-29)% vs. 20(19-25)%; NS]. Organ dysfunction scores (sequential organ dysfunction assessment) were similar between the groups on the fifth post-operative day. Levosimendan favours gastric perfusion but appears not to have a major effect on total splanchnic perfusion in patients undergoing an elective aortic aneurysm operation.

Penetration and Exposure of Cefotiam into the Peritoneal Fluid of Abdominal Surgery Patients after Intravenous Administration

The present study aimed to examine the peritoneal pharmacokinetics and pharmacodynamic exposure of intravenous cefotiam. One gram of cefotiam was administered to eight patients before abdominal surgery. Venous blood and peritoneal fluid (PF) samples were obtained at the end of infusion (0.5 h) and 1, 2, 3, 4, 5, and 6 h afterwards. The drug concentrations in the plasma and PF were determined, analyzed pharmacokinetically, and used for a stochastic simulation with minimum inhibitory concentration (MIC) data. Cefotiam penetrated well into the PF with the area under the drug concentration-time curve ratio of 0.88 ± 0.18 (mean ± SD, n = 8). Regarding the pharmacodynamic exposures against Escherichia coli and Klebsiella species, the probabilities of attaining the bacteriostatic target (40% of the time above MIC) in the PF using 0.5 g every 12 h, 1 g every 12 h, and 2 g every 12 h were 88.3-93.6%. However, 1 g every 8 h was needed for 89.7 and 91.6% probabilities of attaining the bactericidal target (70% of the time above MIC). These results should help us to understand better the peritoneal pharmacokinetics of cefotiam while also helping us to choose the appropriate dosage for intra-abdominal infections.

Effect of Vitamin C Administration on Neutrophil Apoptosis in Septic Patients After Abdominal Surgery

To investigate the effect of parenteral administration of vitamin C on neutrophil apoptosis by determining Fas receptor expression and caspase-3, poly (ADP-ribose) polymerase (PARP), and Bcl-2 levels in neutrophils from septic abdominal surgery patients. Twenty septic abdominal surgery patients were studied in a prospective, randomized, double-blinded clinical trial. A group of healthy volunteers (n = 10) constituted a reference group for baseline parameter values. The patients were randomly assigned to a vitamin C-treated (n = 10) or placebo-treated (n = 10) group. For a 6-d period from 12 h post-surgery, the vitamin C group received 450 mg/d of the vitamin in 3 doses and the placebo group an identical administration of 5% dextrose. Early-morning peripheral blood samples were obtained daily from 24 h after vitamin C administration until d 6 post-surgery (T1d-T6d). Vitamin C group showed a nonsignificant reduction in Fas (CD95) expression on CD15-positive peripheral blood neutrophils, significantly decreased caspase-3, and PARP levels (caspase-3: T4d: P < 0.05, T5d: P < 0.05, T6d P < 0.01; and PARP: T3d: P < 0.05, T4d: P < 0.05, T6d: P < 0.05), and significantly increased Bcl-2 levels (T3d: P = 0.001) versus placebo group. Postoperative vitamin C treatment of septic abdominal surgery patients exerts an antiapoptotic effect on peripheral blood neutrophils, reducing caspase-3 and PARP levels, and increasing Bcl-2 levels. However, these antiapoptotic effects are not maintained at all time points.

Major Abdominal Surgery and Postoperative Pain Control: Are Protocols Enough?

Suitable postoperative pain control (POPC) requires both the application of appropriate pain therapy and the continuous supervision of its therapeutic effects. In our hospital, POPC was, until recently, limited to the first 48 postoperative hours. The purpose of this retrospective study was to assess, the evolution of POPC at the end of the first postoperative 48 hours among major abdominal surgery patients using the Acute Pain Service (APS) database. Further we sought to establish the indications to extend POPC to the entire postoperative period. Regardless of the type of protocol applied after surgery, 79.6% of cases showed pain control was still needed after the 48 th hour. In about half of the cases, POPC was perpetuated with only the drug category or by dosage modifications, while in roughly one third of the cases we adopted both drug and administration route changes. These changes were made by the APS after a thorough evaluation of the patients' conditions and needs in terms of analgesia. Interestingly, in approximately 5% of cases the surgeon decided to interrupt pain therapy. When applying evidence-based guideline protocols, organizational issues are important as well as a better definition of the APS role in POPC, at least from the timing point of view.

Inspirometria de incentivo e breath stacking: repercussões sobre a capacidade inspiratória em indivíduos submetidos à cirurgia abdominal

BACKGROUND: Respiratory complications are the main causes of increased morbidity and mortality in individuals who undergo upper abdominal surgery. The efficacy of physical therapy procedures needs clarification, and it is necessary to know which therapeutic approaches are the best ones to implement. OBJECTIVE: To compare the inspiratory volume during the breath stacking maneuver with the volume during incentive spirometry, in abdominal surgery patients. METHODS: Twelve patients, on their first postoperative day, were instructed to take a deep breath through the VoldyneTM incentive spirometer and to make successive inspiratory efforts using a facemask that had been adapted for performing the breath stacking maneuver. Each technique was performed five times according to the randomization. Before the operation, the patients performed a spirometric test. They were also assessed and instructed about the procedures. A WrightTM ventilometer allowed inspiratory capacity to be recorded. RESULTS: The inspiratory capacity during breath stacking was significantly higher than during incentive spirometry, both before and after the operation. There was a significant reduction in volumes after the surgical procedure, independent of the technique performed. CONCLUSIONS: The breath stacking technique was shown to be effective. This technique was better than incentive spirometry for generating and sustaining inspiratory volumes. Since no adverse effects have been described, this technique can probably be used safely and effectively, particularly in uncooperative patients.

(315) Effects of relaxation/music and patient teaching for pain management on salivary cortisol

Postoperative pain is a major physiological and psychological stressor. Studies have shown that stress and pain leave patients more susceptible to infection and complications. The purpose of this study was to determine whether two interventions, relaxation/music (RM) and patient teaching (PT) for pain management, reduce stress in postoperative abdominal patients. Abdominal surgery patients (N=517) (18-75 yrs) were randomly assigned to receive RM, PT, combination of RM and PT, or control. A 2x2 factorial design with pre and posttests was used to study the overall RM-Effect and PT-Effect on salivary cortisol.

Effect of fondaparinux 2.5 mg once daily on mortality: a meta-analysis of phase III randomized trials of venous thromboembolism prevention

Aims: Fondaparinux significantly reduces death in patients with acute coronary syndromes. The effect of fondaparinux on mortality when used for prevention of venous thromboembolism is unknown. We performed a meta-analysis to examine the effect of fondaparinux 2.5 mg once daily on mortality in phase III randomized trials of venous thromboembolism prevention. Methods and results: Eight trials involving 13 085 patients undergoing major orthopaedic or abdominal surgery or medical patients were included. In five trials, fondaparinux was compared with low-molecular-weight heparin (LMWH); in three trials, the comparator was placebo. The primary efficacy outcome was all-cause mortality up to day 30. The incidence of death was 1.6% (105/6538) in patients treated with fondaparinux compared with 2.1% (134/6547) in patients treated with placebo or LMWH [odds ratio (OR) 0.79; 95% confidence interval (CI) 0.60 to 1.01, P ¼ 0.058; P for heterogeneity ¼ 0.58]. Results were consistent irrespective of whether the comparator was placebo (2.0 vs. 2.6%, OR 0.77; 95% CI: 0.46–1.26) or LMWH (1.5 vs. 1.9%, OR 0.78; 95% CI: 0.58–1.06). Conclusion: The one-fifth reduction in mortality with fondaparinux suggested in randomized trials of venous thromboembolism prevention is not statistically significant, but is externally consistent with the reduction in mortality observed in registry studies and in randomized trials of fondaparinux in patients with acute coronary syndromes.

Electromyographic Evaluation of a Bed Assistive Device for Abdominal Surgery Patients in Postoperative Care

Muscle activity with and without the use of commercially available patient assistive devices during bed rising and lowering was quantified. Limited research is available in understanding or evaluating the physical benefits of assistive devices for patient use following major abdominal surgery. Twenty healthy participants (9 men, 11 women) took part in a laboratory study to test the effects of device configuration (five levels) and bed elevation angle (0 degree and 30 degrees) on mean and peak upper and lower rectus abdominis and external oblique concentric and eccentric muscle activity. Reduced muscle activity was associated with the use of an assistive device, as compared with manual bed rising (unassisted). Positioning the devices at a higher anchor height and/or increasing the bed elevation angle further reduced muscle activity. Objective and subjective differences between the two assistive devices evaluated in the study were found. These results suggest that self-assistive devices may speed recovery because of reduced loads on damaged tissues. Potential applications of this research include the assessment of other commercially available lift aids or comparisons of self-assistive lift aids with hospital-housed lift aids used to speed recovery rates.

Pharmacokinetics and Pharmacodynamic Assessment of Imipenem in the Intraperitoneal Fluid of Abdominal Surgery Patients

Background: Imipenem is used to treat intra-abdominal infections, however, this treatment would benefit from a better understanding of imipenem penetration into the abdominal cavity. Methods: Imipenem 500 mg was infused to 10 laparotomy patients. The total drug concentrations in plasma and intraperitoneal fluid were analyzed noncompartmentally and 3-compartmentally (population pharmacokinetic analysis), and used for a Monte Carlo simulation with minimum inhibitory concentration data. Results: The AUC_0–∞ ratio of the intraperitoneal fluid to the plasma was 0.82 ± 0.06 (mean ± SD, n = 6). The pharmacodynamic exposures in the intraperitoneal fluid were higher than in the plasma. The probabilities of achieving a bacteriostatic/bactericidal target (20/40% of the time above minimum inhibitory concentration for 24 h) in the intraperitoneal fluid using a regimen of 500 mg every 8 h against the Bacteroidesfragilis group, Escherichia coli and Klebsiella species were 97.3/89.1, 98.8/97.2 and 100/98.2%, respectively. However, a regimen of 1,000 mg every 8 h was needed to achieve 96.7/89.3% against Pseudomonas aeruginosa. Conclusion: These results may help us to understand the intraperitoneal penetration of imipenem and to determine the dosing regimen for intra-abdominal infections.

Developing Bariatric Population–Specific Competency for Nurses

The likely increased use of bariatric surgery will heighten the demand for competent postoperative nursing care in more health-care settings across the country. This trend leads to the question of how we can best prepare nurses to care for bariatric surgery patients. A bariatric population–specific competency for nurses is one answer that guides training and assessment. This paper describes an evidence-based bariatric competency for nurses that could supplement existing clinical care practices for any general abdominal surgery patients, provide the basis for developing competency-based training programs for nurses caring for bariatric patients, and be used as a generic template that can be customized for preceptors' use in selected centers.

Peritoneal penetration and pharmacodynamic exposure of intravenous cefozopran in abdominal surgery patients

This study aimed to examine the peritoneal penetration and pharmacodynamic exposure of intravenous cefozopran. Cefozopran 1 g was administered to 10 patients before abdominal surgery. Venous blood and peritoneal fluid (PF) samples were obtained at the end of the 0.5-h infusion and at 1, 2, 3, 4, 5 and 6 h thereafter. Drug concentrations in plasma and PF were determined, analysed pharmacokinetically and used for a Monte Carlo simulation with minimum inhibitory concentration (MIC) data. Cefozopran penetrated well into PF, with a mean (±standard deviation) maximum drug concentration in PF/plasma ratio of 0.65 ± 0.17 ( n = 10) and area under the concentration–time curve ratio of 0.92 ± 0.13. The probabilities of attaining the pharmacodynamic exposure target (PTA), defined as 70% of the time above the MIC, in PF were almost identical to those in plasma. The PTAs were 95–100% against Escherichia coli, Enterobacter spp. and Staphylococcus aureus with 0.5 g every 12 h; however, 1 g every 8 h or 1 g every 6 h was required for 93–98% PTA against Pseudomonas aeruginosa. These results should help us to understand the peritoneal pharmacokinetics of cefozopran whilst also helping to choose the appropriate dosage for surgical intra-abdominal infections.

Pharmacokinetic and pharmacodynamic profiling of cefepime in plasma and peritoneal fluid of abdominal surgery patients

This study was conducted to characterise the pharmacokinetics and pharmacodynamics of cefepime in plasma and peritoneal fluid (PF). One gram of cefepime was administered to eight laparotomy patients and plasma and PF samples were collected at the end of 0.5 h infusion and every hour for 6 h. Drug concentrations were determined, analysed by population pharmacokinetic modelling and used for a Monte Carlo simulation with minimum inhibitory concentration (MIC) data. The maximum concentration in PF was two-thirds of the value in plasma; however, the concentrations were higher in PF than in plasma at 0.68 h post dose. The probabilities of attaining the pharmacodynamic target (65% of the time above the MIC) were 92–99% in plasma (90% fraction unbound) and 93–100% in PF against Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae with a regimen of 1 g every 12 h. However, 1 g every 8 h or 2 g every 12 h was required for values of 94–95% in plasma and 95–96% in PF against Pseudomonas aeruginosa. These results demonstrate that the pharmacodynamic exposures in PF were almost identical to those estimated from plasma data and provided a pharmacokinetic/pharmacodynamic rationale for the dosing regimen for surgical intra-abdominal infections.

Venous Thromboembolism: A Review of Risk and Prevention in Colorectal Surgery Patients

Hospitalization for surgery has a high risk of developing venous thromboembolism, a condition that encompasses both deep-vein thrombosis and its potentially fatal complication, pulmonary embolism. Colorectal surgery implies a specific high risk for postoperative thromboembolic complications relative to other general surgery. This may be a result of pelvic dissection, the perioperative positioning of these patients, or the presence of additional risk factors common to this patient group, such as cancer, advanced age, or inflammatory bowel disease. The potential impact of venous thromboembolism and the need for effective thromboprophylaxis often are underestimated in these patients. Recommendations for thromboprophylaxis in colorectal surgery patients are based on the American College of Chest Physicians guidelines for thrombosis prevention in general surgery patients, with treatment stratified according to the type of surgery and additional venous thromboembolism risk factors present. Prophylaxis with low-molecular-weight heparin or unfractionated heparin is recommended for colorectal surgery patients classified as moderate to high risk. The small number of studies focusing specifically on colorectal patients, or on cancer or abdominal surgery patients with a colorectal subgroup, has shown that both low-molecular-weight heparin and unfractionated heparin can effectively reduce the incidence of venous thromboembolism. Low-molecular-weight heparin has the practical advantage of once-daily administration and shows a lower risk of heparin-induced thrombocytopenia. This review will assess the risk of venous thromboembolism in colorectal surgery patients and discuss current evidence-based guidelines and recommendations for prevention of venous thromboembolism.

Comparison of the transcutaneous oxygen and carbon dioxide tension in different electrode locations during general anaesthesia

The best place for the electrode of transcutaneous measurement of oxygen tension (tcPO2) and carbon dioxide tension (tcPCO2) during general anaesthesia was investigated in three different locations. Fifteen patients for major abdominal surgery in the supine position were studied. The electrode of the TCM4 (Radiometer, Copenhagen, Denmark) was put on the chest, upper arm or forearm. TcPO2, tcPCO2, end-tidal carbon dioxide tension (etCO2), percutaneous oxygen saturation (SaO2), arterial oxygen tension (PaO2 ) and arterial carbon dioxide tension (PaCO2) were simultaneously measured at four different etCO2 concentrations and inhaled oxygen percentages and the location of the electrode was changed to other places to repeat the same measurement. In total, 12 measurements for each patient and 60 measurements for each place were performed. TcPO2 correlated better than SaO2 (R2 = 0.58) with PaO2 (R2 = 0.76), and tcPCO2 correlated well with PaCO2 (R2 = 0.76) and etCO2 (R2 = 0.74) when the electrode was put on the chest, while not on the upper arm or forearm (R2 < 0.5). However, limits of agreement were too big to use tcPO2 (bias, -67.9; limits of agreement, 16.5, -152.3) and tcPCO2 (bias, -0.47; limits of agreement, 8.7, -9.64) as surrogate measures of PaO2 and PaCO2, respectively even when the electrode was put on the chest. When the electrode was put on the chest, tcPO2 and tcPCO2 might be available as non-invasive monitors of oxygenation and CO2 status during general anaesthesia, while the absolute values were not interchangeable with PaO2 and PaCO2, respectively.