Continuous extradural infusion of ropivacaine for prevention of postoperative pain after major orthopaedic surgery

We studied 151 patients undergoing total hip or knee arthroplasty, or cruciate ligament reconstruction in a multicentre study in Australia and New Zealand. Patients were openly allocated randomly to one of five treatment groups or to a control group. General anaesthesia was induced after introduction of extradural block with 0.5% ropivacaine. After surgery, patients received an extradural infusion of 0.2% ropivacaine at 6, 8, 10, 12 or 14 ml h-1 or received no postoperative extradural infusion (control group). All patients had access to i.v. PCA morphine for supplementary analgesia. Morphine consumption was lower in all treatment groups compared with the control group, decreasing with increasing ropivacaine infusion rate. Median VAS scores were lower in all ropivacaine infusion groups compared with the control group for the first 10 h of the study; however by the end of the study, VAS scores were similar in all groups. The higher ropivacaine infusion rates caused a slower convergence of spread of the initial sensory block and a higher degree of motor block. The overall incidence of side effects was similar, with the exception of a higher incidence of urinary retention and hypotension in the groups receiving the higher rates of ropivacaine. The quality of treatment scores were similar for all treatment groups (Br. J. Anaesth. 1996; 76: 606-610).

Unrecognized pertussis infection in adolescents

Little information is available regarding the level of immunity to Bordetella pertussis among adolescents. We measured serum antibodies in 156 healthy adolescents to the following pertussis antigens: pertussis toxin, filamentous hemagglutinin, and 69-kd outer membrane protein. In an attempt to identify intercurrent pertussis infections, we also obtained a total of 43 repeated samples during the following 5 years. Using a 50% or greater rise in IgG enzyme-linked immunosorbent assay titers to define seroconversion, we found an annual incidence of 6.1%; by alternative definitions of seropositivity, the predicted annual incidence of infection ranged from 1.2% to 8.2%. These data suggest that infection with B pertussis is common in the adolescent population.

Adult immunization with acellular pertussis vaccine

OBJECTIVE

To evaluate the safety and immunogenicity in adults of several different concentrations of an acellular pertussis vaccine.

DESIGN

Double-blind, randomized, placebo-controlled trial.

SETTING

Medical center immunization clinic.

PARTICIPANTS

One hundred eighteen healthy adult volunteers.

INTERVENTIONS

Participants received standard adult tetanus-diphtheria vaccine alone or combined with full-strength, half-strength, or quarter-strength concentrations of a currently licensed acellular pertussis vaccine used for booster doses in young children. Full-strength vaccine contained 40 micrograms of pertussis proteins, consisting of 86% filamentous hemagglutinin, 8% pertussis toxin, 4% 69-kd outer-membrane protein, and 2% agglutinogens.

MAIN OUTCOME MEASURES

Local and systemic reactions were assessed for 14 days after vaccination. Serum samples for antibody assay were obtained before, 1 month after, and 1 year after immunization.

RESULTS

Adverse reactions were few and minor and did not differ in frequency or severity among the four study groups. The groups receiving acellular pertussis vaccine showed strong antibody responses to pertussis antigens, which did not significantly differ by concentration of vaccine. After 1 year, levels of antibody to pertussis had declined by approximately 50% but remained substantially higher than preimmunization levels. The four groups did not differ in antibody responses to tetanus or diphtheria toxoids.

CONCLUSIONS

Routine reimmunization of adults with a vaccine containing acellular pertussis antigens in addition to diphtheria and tetanus toxoids can substantially enhance pertussis antibody levels without an increase in adverse reactions or diminution in response to the diphtheria and tetanus components. Such a program might materially reduce respiratory illness among both adults and children.