Chronic angiotensin-converting enzyme inhibitor or angiotensin receptor blocker therapy combined with diuretic therapy is associated with increased episodes of hypotension in noncardiac surgery.

OBJECTIVE: Chronic angiotensin-converting enzyme inhibitor (ACE-I) or angiotensin receptor blocker (ARB) therapy has been reported to result in intraoperative hypotension in patients undergoing general anesthesia. This study evaluated the association between ACE-I/ARB therapy and the hemodynamics of patients undergoing noncardiac surgery using a large patient dataset. DESIGN AND SETTING: A prospective, observational study performed at a single tertiary care hospital. PARTICIPANTS: All adult patients undergoing noncardiac surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Propensity score matching for the likelihood of chronic ACE-I/ARB therapy was used to create 2 patient cohorts with similar cardiovascular and pulmonary comorbidities. The number of periods of absolute and relative hypotension, vasopressor requirements, and postoperative myocardial infarction and renal failure rates were compared among patients with and without ACE-I/ARB therapy. A total of 65,043 noncardiac cases between 2003 and 2006 were included. Two-digit propensity score matching resulted in a study population of 12,381 operative cases with very similar cardiovascular comorbidities between the ACE-I/ARB and control cohort. Patients with chronic ACE-I/ARB and diuretic therapy showed more periods with a mean arterial pressure <70 mmHg, periods with a 40% decrease in systolic blood pressure, periods with a 50% decrease in systolic blood pressure, and vasopressor boluses when compared with patients with diuretic therapy alone. There were no statistically significant differences in the rates of postoperative myocardial infarction or renal failure between patients with and without ACE-I/ARB therapy. CONCLUSIONS: Chronic diuretic therapy is associated with more frequent hypotension in ACE-I/ARB-treated patients undergoing noncardiac surgery.

The pharmacodynamic effects of a lower-lipid emulsion of propofol: a comparison with the standard propofol emulsion.

UNLABELLED: Using a randomized, double-blind protocol design, we compared a new lower-lipid emulsion of propofol (Ampofol) containing propofol 1%, soybean oil 5%, and egg lecithin 0.6% with the most commonly used formulation of propofol (Diprivan) with respect to onset of action and recovery profiles, as well as intraoperative efficacy, when administered for induction and maintenance of general anesthesia as part of a "balanced" anesthetic technique in 63 healthy outpatients. Anesthesia was induced with sufentanil 0.1 microg/kg (or fentanyl 1 microg/kg) and propofol 2 mg/kg IV and maintained with a variable-rate propofol infusion, 120-200 microg x kg(-1) x min(-1). Onset times to loss of the eyelash reflex and dropping a syringe were recorded. Severity of pain on injection, speed of induction, intraoperative hemodynamic variables, and electroencephalographic bispectral index values were assessed. Recovery times to opening eyes and orientation were noted. The results demonstrated that there were no significant differences between Ampofol and Diprivan with respect to onset times, speed of induction, anesthetic dose requirements, bispectral index values, hemodynamic variables, recovery variables, or patient satisfaction. However, the incidence of pain on injection was more frequent in the Ampofol group (26% versus 6%, P < 0.05). We conclude that Ampofol is equipotent to Diprivan with respect to its anesthetic properties but was associated with a more frequent incidence of mild pain on injection. IMPLICATIONS: The pharmacodynamic profile of a lower-lipid containing emulsion of propofol (Ampofol) was compared with Diprivan when administered for induction and maintenance of general anesthesia. This preliminary study demonstrated that the two formulations of propofol were equivalent with respect to their induction and maintenance properties. However, Ampofol was associated with a more frequent incidence of pain on injection.

Effect of a transpositional muscle flap on VEGF mRNA expression in a canine fracture model.

The effect of sepsis on neovascularization in fractures that follows open fractures is important to the understanding of bone and soft-tissue healing. An animal model was designed that mimics the open fracture and the clinical repair of the human, high-energy open fracture. Vascular endothelial growth factor (VEGF) mRNA levels in canine bone samples were determined in samples from days 0 and 7. Canine right tibiae were fractured with a penetrating, captive-bolt device and then repaired in a standard clinical fashion using an interlocking intramedullary nail. Animals were subject to one of the following experimental protocols: tibial fracture (group I, n = 3); tibial fracture and Staphylococcus aureus inoculation at the fracture site (group II, n = 3); and tibial fracture and S. aureus inoculation with a rotational gastrocnemius muscle flap (group III, n = 3). Bone samples were harvested on days 0 and 7 and prepared for reverse transcriptase polymerase chain reaction assay. Primers for VEGF were commercially prepared and assay products were sequenced. The assay products were associated with Genebank VEGF mRNA sequences. VEGF mRNA levels increased significantly in the fracture-alone group from day 0 to day 7 (n = 3, p < 0.05). In the fracture and S. aureus group (group I), VEGF mRNA expression decreased 79 percent (p < 0.05). In animals with fractures inoculated with S. aureus and a transpositional muscle flap (group III), VEGF mRNA expression was increased 38 percent from day 0 to day 7 (p < 0.05) and was similar to the increase observed in the fracture-alone group. These results demonstrate that S. aureus decreased the normal increase of VEGF mRNA expression during bone wound healing. Use of the transpositional muscle flap in the presence of S. aureus increased VEGF mRNA expression over time to the expression pattern observed in the fracture-alone group. This experimental model demonstrates that specific biological signals and cellular pathways are influenced by bacterial infection and type of surgical closure.