Anesthesia and analgesia
-
In previous studies, we showed that failure to respond to automated responsiveness monitor (ARM) precedes potentially serious sedation-related adversities associated with loss of responsiveness, and that the ARM was not susceptible to false-positive responses. It remains unknown, however, whether loss and return of response to the ARM occur at similar sedation levels. We hypothesized that loss and return of response to the ARM occur at similar sedation levels in individual subjects, independent of the propofol effect titration scheme. ⋯ Reproducible ARM dynamics in individual subjects compares favorably with clinical and electroencephalogram sedation end points and suggests that the ARM could be used as an independent instrumental guide of drug effect during propofol-only sedation.
-
Anesthesia and analgesia · Sep 2009
Cytokine gene expression after total hip arthroplasty: surgical site versus circulating neutrophil response.
After surgery, cytokines and chemokines are released at the surgical wound site, which can contribute to postoperative pain, local inflammation, and tissue repair. Multiple cell types are present that can release cytokines/chemokines at the wound site and, thus, the exact cellular source of these molecules is unclear. We sought to better understand the contribution of neutrophils to cytokine/chemokine gene expression at the surgical wound site during the initial postsurgery phase of total hip arthroplasty (THA). ⋯ There is a distinct cytokine gene expression profile in neutrophils at the THA surgical wound site at 24 h postsurgery when compared with that found in presurgery circulating neutrophils. Understanding these changes may allow us to knowledgeably manipulate neutrophil activity to reduce postoperative pain and inflammation without impairing wound healing.
-
Anesthesia and analgesia · Sep 2009
Increasing the duration of isoflurane anesthesia decreases the minimum alveolar anesthetic concentration in 7-day-old but not in 60-day-old rats.
While studying neurotoxicity in rats, we observed that the anesthetic minimum alveolar anesthetic concentration (MAC) of isoflurane decreases with increasing duration of anesthesia in 7-day-old but not in 60-day-old rats. After 15 min of anesthesia in 7-day-old rats, MAC was 3.5% compared with 1.3% at 4 h. We investigated whether kinetic or dynamic factors mediated this decrease. ⋯ MAC of isoflurane decreases over 1-4 h of anesthesia in 7-day-old but not in 60-day-old rats. Both pharmacodynamic and a pharmacokinetic components contribute to the decrease in MAC in 7-day-old rats. Neither endorphins nor sensory desensitization mediate the pharmacodynamic component.
-
Anesthesia and analgesia · Sep 2009
Sciatic nerve catheter placement: success with using the Raj approach.
Continuous regional analgesia has increased in popularity and is becoming standard of care for many painful surgical procedures. Various approaches of sciatic catheter insertion have been proposed, each with attributes and disadvantages. We investigated whether the Raj approach that uses a simple midpoint landmark between the ischial tuberosity and greater trochanter will facilitate sciatic catheter placement. ⋯ Use of a simple landmark between easily identifiable bony structures enhances the simplicity and placement of a sciatic nerve catheter and is recommended for use in clinical practice.