• E-mail
• Print
• Comment
• Font Size
• Digg
• del.icio.us
• Discuss article

Transrectal Ultrasound-Guided Biopsy; Vacuum Mixing Systems; Regional Anesthesia; Laparoscopic Cholecystectomy

Posted on: Saturday, 19 March 2005, 03:00 CST

Local anesthesia use in transrectal ultrasound-guided biopsy

The Surgeon

August 2004

Transrectal ultrasound (TRUS)-guided biopsy of the prostate is a common diagnostic procedure for prostate cancer. It involves the use of an ultrasound probe that is passed into the rectum where sound waves are used to visualize the prostate on a monitor. Under this direct visualization, a special biopsy needle is precisely introduced through the rectal wall into the prostate to obtain tissue from a number of sites. Although this procedure has routinely been performed without anesthesia, it is associated with significant pain in some individuals. The purpose of this prospective, randomized, placebocontrolled study was to determine the efficacy and safety of using local anesthesia (ie, periprostatic lidocaine injection) for TRUS-guided biopsy of the prostate.1

Ninety-six patients undergoing TRUS-guided biopsy of the prostate were randomly assigned to one of two groups. Forty-eight patients were assigned to the local anesthesia (LA) group and 48 to the placebo group. In the LA group, lidocaine 1% was injected into the angle between the seminal vesicle and base of the prostate and the apex of the prostate before the usual six to 12 biopsies were performed with an 18-gauge core-biopsy needle. The identical procedure was performed in the placebo group without the injection of lidocaine.

Patients' level of anxiety was determined before the procedure using a visual analog scale (ie, expected pain score). Similarly, at the end of the procedure, the actual pain score was determined using the same visual analog scale, and the patients were asked if they would undergo the procedure again in the same way. Immediately after the procedure, patients were monitored for complications, including hematuria, hemospermia, rectal bleeding, infection, and urinary retention. After they were discharged, patients were contacted by telephone to assess the incidence of these complications. Common statistical techniques, including, Student's I test and MannWhitney U tests, were used to analyze differences between the groups.

Findings. Both groups were similar with regard to age and mean prostatespecific antigen levels. The mean expected pain score was similar in both groups (5.19 1.6 in the LA group, 5.02 1.4 in the placebo group, P = .587). The mean actual pain score was significantly higher in the placebo group (6.46 2.2 in the placebo group, 3.0 1.8 in the LA group, P = .0001). Complication rates were comparable in both groups. All patients in the LA group (ie, 100%) were significantly more likely to indicate that they would be happy to undergo the procedure in the same way the next time compared to 65% in the placebo group (P = .0001).

Clinical implications. Perioperative nurses should understand that when patients expect to experience pain and discomfort, their anxiety increases. This study revealed that periprostatic injection of local anesthesia is safe and effective and significantly reduces discomfort during TRUS-guided prostate biopsy.

Efficacy of vacuum mixing systems in reducing methyl- methacrylate fumes

Acta Orthopaedica Scandinavica

October 2004

Polymethyl methacrylate (PMMA) bone cement is used mainly during the implantation of orthopedic prostheses. Methylmethacrylate (MMA) fumes are generated during the mixing procedure. These fumes are toxic and may have irritating effects on mucous membranes of the respiratory tract and eyes. Additionally, direct contact with PMMA may lead to toxic dermatitis. Vacuum mixing of PMMA bone cement is advocated to reduce cracks within the cement mantle and minimize exposure to MMA fumes evaporating during the cement mixing process. The objective of this study was to determine if vacuum mixing of PMMA bone cement is effective in reducing exposure to MMA vapors.2

During joint replacement surgery in a conventional OR with laminar air flow, the emission of MMA fumes in the breathing zone was quantified. Seven commonly available vacuum mixing systems were compared with hand mixing in an open bowl. Humidity and temperature were measured and recorded every two hours. The mixing systems being examined were placed on a table near the scrub person during joint replacement surgery. The fume detection systems were mounted on a second table within the breathing zone of a nurse during the mixing process. Air and fume samples were collected during a three-minute period, using both a photo ionization detector and gas chromatography. Ten separate mixes were made, and measurements were taken for each mixing device. Common statistical techniques, including univariate analysis of variance (ANOVA) were used to analyze differences.

Findings. Methylmethacrylate evaporated continuously from the mixing systems into the breathing zone during mixing. Gas chromatography revealed significantly lower concentrations of MMA fumes compared to hand mixing when six of the seven mixing systems were used (one-way ANOVA: F = 70, df=7,P< .001, R-square = 0.69). Photo ionization detection revealed significantly lower concentrations of MMA compared to hand mixing when four of the seven mixing systems were used (oneway ANOVA: F = 25, df=7,P < .001, R- square = 0.71). All the vacuum mixing systems reduced MMA fume exposure by approximately 50% to 75% compared to hand mixing in an open bowl.

Clinical implications. The results of this study showed that vacuum mixing systems significantly reduced exposure to MMA vapors compared to hand mixing, but systems differ in their effectiveness. Managers should take these findings into consideration when evaluating cement-mixing vacuum systems.

Regional anesthesia for patients with pulmonary impairment

American Journal of Surgery

November 2004

Patients with preexisting pulmonary disease, such as chronic obstructive pulmonary disease (COPD), are significantly more likely to develop postoperative pulmonary complications than are individuals without those conditions. Such complications may result in ventilator dependence or death, particularly after upper abdominal surgical procedures. Consequently, patients with pulmonary disease may be denied elective abdominal surgery.

It has been proposed that such complications largely are related to the effects of general anesthesia and the problem of controlling postoperative pain. It also has been proposed that use of regional anesthesia may be a viable alternative. The objective of this retrospective study was to provide evidence that many abdominal surgical procedures thought to require general anesthesia could be safely and effectively performed using regional anesthesia alone.3

The surgical records of patients treated at the McGuire Veterans Affairs Medical Center, Richmond, Va during a two-year period were reviewed. Patients who had evidence of severe pulmonary impairment, defined as forced expiratory volume in one second less than 50% predicted and/or a preoperative home oxygen requirement, and who had abdominal surgery using regional anesthesia were identified. Additionally,

* patient age,

* presenting diagnosis,

* indications for surgery,

* type of procedure performed,

* American Society of Anesthesiology (ASA) classification,

* need for general anesthesia,

* need for mechanical ventilation,

* length of stay, and

* perioperative complication or mortality were assessed.

Findings. Eight patients met the study criteria. Mean age of the patients was 74.1 years; procedures performed included sigmoidectomy, open cholecystectomy, incisional hernia repair, and laparoscopic inguinal hernia repair. Three patients (38%) required oxygen at home, and five patients (63%) were classified as ASA 4. The surgical procedures performed on all eight patients were successfully completed using regional anesthesia alone. Five (63%) of the patients were discharged in less than 24 hours. There were no deaths. Only one patient developed a postoperative complication. The patient developed pneumonia on postoperative day eight that was successfully treated with standard medical therapy and without mechanical ventilatory support.

Clinical implications. The results of this study provide evidence that regional anesthesia can be safely and effectively used in patients who have preexisting pulmonary diseases. Perioperative nurses need to be aware that the number of patients with chronic pulmonary diseases undergoing abdominal surgery may increase and should be prepared to monitor these patients during use of regional anesthesia.

Conversion from laparoscopic to open cholecystectomy

American Journal of Surgery

September 2004

Choleystectomy is one of the most frequently performed general surgical procedures. The laparoscopic approach has transformed this procedure and resulted in a reduction in the postoperative disability associated with open choleystectomy. After laparoscopic cholecystectomy, patients have less pain, a shorter hospital stay, and a shorter recovery time and can return to work more quickly. With wider use of this procedure, however, it is expected that more complications will result, and more procedures will be converted from the laparoscopic to the open approach. The purpose of this study was to determine the national incidence and risk factors for convert\ing from laparoscopic to open cholecystectomy.4

Researchers analyzed the National Hospital Discharge Summary (NHDS) for cholecystectomy for 1998 to 2001. The NHDS is the principal database used by the US Government for monitoring hospital use. Each year, this database contains a subset of approximately 300,000 hospital discharges representing 35 million total discharges nationally.

Hospitalized patients undergoing cholecystectomy were identified by having international classification of diseases procedure codes of 51.22 (ie, cholecystectomy) or 51.23 (ie, laparoscopic cholecystectomy). Conversion was identified by diagnostic code V64.4 (ie, laparoscopic surgical procedure converted to open procedure). The conversion rate was calculated, and logistic regression techniques were used to determine the risk factors.

Findings. Approximately 25% of all cholecystectomies were performed by the open method. The conversion rate from laparoscopic to open cholecystectomy ranged from 3% to 24% (average 5% to 10%) and generally was associated with the presence of acute or chronic cholecystitis. The most complex disease was associated with the highest conversion rate. Combined cholelithiasis, choledocholithiasis, and acute cholecystitis had the highest rate of open procedures (44%) and the highest laparoscopic to open conversion rate (24%). Other major risks for conversion included obesity and being male.

Clinical implications. This study revealed that, on average, conversion from laparoscopic to open cholecystectomy was 5% to 10%, and risk factors for conversion were associated with the simultaneous presence of cholelithiasis, choledocholithiasis, and cholecystitis; obesity; and the male gender. Perioperative nurses can use these findings to effectively and expeditiousIy manage patients undergoing laparoscopic cholecystecomy by understanding which patients' procedures are likely to convert to open procedures.

This information is intended for general use only. The clinical implications are specific to the abstracted article only. Individuals intending to put these findings into practice are strongly encouraged to review the original article to determine its applicability to their setting.

NOTES

1. T Nambirajan et al, "Efficacy and safety of peri-prostatic local anaesthetic injection in trans-rectal biopsy of the prostate: A prospective randomized study," The Surgeon 2 (August 2004) 221- 224.

2. U J Schlegel et al, "Efficacy of vacuum bone cement mixing systems in reducing methylmethacrylate fume exposure: Comparison of 7 different mixing devices and handmixing," Acta Orthopaedica Scandinavica 75 (October 2004) 559-566.

3. J F Savas et al, "Regional anesthesia as an alternative to general anesthesia for abdominal surgery in patients with severe pulmonary impairment," American Journal of Surgery 188 (November 2004) 603-605.

4. E H Livingston, R V Rege, "A nationwide study of conversion from laparoscopic to open cholecystectomy," American Journal of Surgery 188 (September 2004) 205-211.

George Allen, RN

GEORGE ALLEN

RN, PHD, CNOR, CIC

DIRECTOR OF INFECTION CONTROL

DOWNSTATE MEDICAL CENTER

BROOKLYN, NY

Copyright Association of Operating Room Nurses, Inc. Mar 2005

Source: Association of Operating Room Nurses. AORN Journal

More News in this Category