Evaluation of amoxicillin, metronidazole and gentamicin dosage regimens for use in antibiotic prophylaxis in colorectal surgery.

OBJECTIVES: To evaluate amoxicillin, metronidazole and gentamicin dosage regimens for antibiotic prophylaxis in colorectal surgery. METHODS: The study was conducted in 20 patients undergoing colorectal surgery. Patients received one or two doses of amoxicillin 1000 mg, metronidazole 500 mg and gentamicin 3 mg/kg ideal body weight, banded by height. Antibiotic concentrations were measured up to 7 h post dose. Population pharmacokinetic (PopPK) analysis with NONMEM followed by Monte Carlo simulation of different dosage regimens was used to estimate the PTA for potential organisms associated with surgical site infections (SSIs). RESULTS: A median of 5 (range 3-6) concentrations were available per patient. CL and V of all antibiotics were related to weight; gentamicin CL was also related to CLCR. The administered doses maintained the desired PTA up to 8 h for the Streptococcus anginosus group but not for enterococci, Bacteroides fragilis group, MSSA, and Escherichia coli. An additional 500 mg amoxicillin every 4 h was sufficient to achieve the PTA for most relevant organisms but 2 hourly dosing was required for patients at risk of infective endocarditis. A metronidazole dose of 1000 mg was required for patients >85 kg. In patients with CLCR >50 mL/min, 5 mg/kg gentamicin (with an additional 2.5 mg/kg in prolonged surgery at 6 h) maintained PTA targets for >10 h. CONCLUSIONS: PopPK analysis with Monte Carlo simulation identified prophylactic antibiotic regimens that would maintain the PTA for organisms associated with SSIs during short- and long-duration colorectal surgery.

Pre-operative carbohydrate loading prior to elective caesarean delivery: a randomised controlled trial.

INTRODUCTION: Women undergoing elective caesarean deliveries are fasted for long periods prior to surgery and can become catabolic. The use of pre-operative carbohydrate drinks to optimise patients ahead of major surgery is now well established. However, evidence to support this in women undergoing elective caesarean delivery is limited. METHODS: We conducted a single-blind randomised control trial to study the effect of carbohydrate preloading on the presence of urinary ketones in mothers undergoing elective caesarean deliveries compared with standard care, fasting from midnight the night before surgery with free clear fluids until two hours prior to surgery. RESULTS: Two-hundred-and-nine patients were allocated to either standard care (n=104) or pre-operative carbohydrate drinks (n=105) prior to elective caesarean section. Twenty-five were excluded from the analysis, leaving 184 (n=90; n=94). The incidence of urinary ketones immediately prior to surgery was lower in the carbohydrate group, 18.1% compared with 61.1% in the standard care group (P<0.001). Relative risk (95% CI) 3.33 (2.12 to 5.26), with a number needed-to-treat of three to prevent urinary ketosis in one woman. There were no major adverse events. CONCLUSION: The results of this study support the introduction of carbohydrate drinks ahead of caesarean delivery to offset the effects of pre-operative fasting. However, the results may not be generalisable to all maternity units due to differences in fasting protocols.

Achondroplasia: anaesthetic challenges for caesarean section.

Pregnancy in women with achondroplasia presents major challenges for anaesthetists and obstetricians. We report the case of a woman with achondroplasia who underwent general anaesthesia for an elective caesarean section. She was 99cm in height and her condition was further complicated by severe kyphoscoliosis and previous back surgery. She was reviewed in the first trimester at the anaesthetic high-risk clinic. A multidisciplinary team was convened to plan her peripartum care. Because of increasing dyspnoea caesarean section was performed at 32weeks of gestation. She received a general anaesthetic using a modified rapid-sequence technique with remifentanil and rocuronium. The intraoperative period was complicated by desaturation and high airway pressures. The woman's postoperative care was complicated by respiratory compromise requiring high dependency care.

Inadequate pain relief with labor epidurals: a multivariate analysis of associated factors.

BACKGROUND: Labor epidural analgesia providing inadequate pain relief may cause maternal dissatisfaction and may fail to produce effective anesthesia when topped up for operative delivery. This study looked at factors associated with inadequate labor epidural analgesia. METHODS: Data were prospectively collected from 275 parturients receiving labor epidural analgesia. Pain was assessed 30 min after epidural insertion using a verbal pain scale of 0 to 100. A score of 10 or more was considered to represent inadequate pain relief. Sixteen factors chosen by experienced obstetric anesthesiologists for their association with inadequate labor epidural analgesia were studied. RESULTS: Fifteen parturients were excluded. Forty-four of the remainder (16.9%) experienced inadequate pain relief. Multiparity, history of a previous failure of epidural analgesia, the use of air for loss of resistance, cervical dilatation >7 cm at insertion all had a statistically significant association with inadequate epidural analgesia (P<0.05). Logistic regression showed that cervical dilatation >7 cm, a history of opioid tolerance, a previous failed epidural and insertion of the epidural by a trainee anesthesiologist increased the odds ratio for inadequate pain relief. CONCLUSIONS: The final model correctly classified 93% of the epidurals that provided effective analgesia but classified only 9.3% of those providing inadequate pain relief. This information can be used to develop a predictive score and change practice resulting in fewer inadequate epidurals.