James F. Arens

Practice guidelines for obstetric anesthesia: An updated report by the American Society of Anesthesiologists Task Force on obstetric anesthesia

PRACTICE guidelines are systematically developed recommendations that assist the practitioner and patient in making decisions about health care. These recommendations may be adopted, modified, or rejected according to clinical needs and constraints and are not intended to replace local institutional policies. In addition, practice guidelines are not intended as standards or absolute requirements, and their use cannot guarantee any specific outcome. Practice guidelines are subject to revision as warranted by the evolution of medical knowledge, technology, and practice. They provide basic recommendations that are supported by a synthesis and analysis of the current literature, expert opinion, open forum commentary, and clinical feasibility data. This update includes data published since the “Practice Guidelines for Obstetrical Anesthesia” were adopted by the American Society of Anesthesiologists in 1998; it also includes data and recommendations for a wider range of techniques than was previously addressed.

Practice advisory for preanesthesia evaluation: an updated report by the American Society of Anesthesiologists Task Force on Preanesthesia Evaluation.

P RACTICE Advisories are systematically developed reports that are intended to assist decision-making in areas of patient care. Advisories provide a synthesis and analysis of expert opinion, clinical feasibility data, open forum commentary, and consensus surveys. Practice Advisories developed by the American Society of Anesthesiologists (ASA) are not intended as standards, guidelines, or absolute requirements, and their use cannot guarantee any specific outcome. They may be adopted, modified, or rejected according to clinical needs and constraints and are not intended to replace local institutional policies. Practice Advisories are not supported by scientific literature to the same degree as standards or guidelines because of the lack of sufficient numbers of adequately controlled studies. Practice Advisories are subject to periodic update or re-

Is Extended Hepatectomy for Hepatobiliary Malignancy Justified

Background:Extended hepatectomy may be required to provide the best chance for cure of hepatobiliary malignancies. However, the procedure may be associated with significant morbidity and mortality. Methods:We analyzed the outcome of 127 consecutive patients who underwent extended hepatectomy (resection of ≥ 5 liver segments) for hepatobiliary malignancies. Results:The patients underwent extended hepatectomy for colorectal metastases (n = 86; 67.7%), hepatocellular carcinoma (n =12; 9.4%), cholangiocarcinoma (n =14; 11.0%), and other malignant diseases (n =15; 11.5%). Thirty-two left and ninety-five right extended hepatectomies were performed. Eight patients also underwent caudate lobe resection, and 40 patients underwent a synchronous intraabdominal procedure. Twenty patients underwent radiofrequency ablation, and 31 underwent preoperative portal vein embolization. The median blood loss was 300 mL for right hepatectomy and 600 mL for left hepatectomy (P = 0.02). Thirty-six patients (28.3%) received a blood transfusion. The overall complication rate was 30.7% (n = 39), and the operative mortality rate was 0.8% (n = 1). Significant liver insufficiency (total bilirubin level > 10 mg/dL or international normalized ratio > 2) occurred in 6 patients (4.7%). Multivariate analysis showed that a synchronous intraabdominal procedure was the only factor associated with an increased risk of morbidity (hazard ratio [HR], 4.9; P = 0.02). The median survival was 41.9 months. The overall 5-year survival rate was 25.5%. Conclusions:Extended hepatectomy can be performed with a near-zero operative mortality rate and is associated with long-term survival in a subset of patients with malignant hepatobiliary disease. Combining extended hepatectomy with another intraabdominal procedure increases the risk of postoperative morbidity.

The development of evidence-based clinical practice guidelines. Integrating medical science and practice.

Practice guidelines are rapidly becoming preferred decision-making resources in medicine, as advances in technology and pharmaceutics continue to expand. An evidence-based approach to the development of practice guidelines serves to anchor healthcare policy to scientific documentation, and in conjunction with practitioner opinion can provide a powerful and practical clinical tool. Three sources of information are essential to an evidence-based approach: a) an exhaustive literature synthesis; b) meta-analysis; and c) consensus opinion. The systematic merging of evidence from these sources offers healthcare providers a scientifically supportable document that is flexible enough to deal with clinically complex problems. Evidence-based practice guidelines, in conjunction with practice standards and practice advisories, are invaluable resources for clinical decision making. The judicious use of these documents by practitioners will serve to improve the efficiency and safety of health care well.

Endotracheal Tube Cuff Residual Volume and Lateral Wall Pressure in a Model Trachea

The authors constructed a D-shaped tracheal model with an elastic posterior wall, thus simulating normal tracheal anatomy more closely than previous models. The performance of 9-10 tracheal tube cuffs, of 2-3 different tube sizes (7.0-10.0 mm, ID), from six different manufacturers were tested in the model. Cuff residual volumes ranged from 1.78 to 27.35 ml. Cuff pressure and lateral wall pressures exerted by the cuff on the model were measured at the time a seal was achieved which just prevented leakage of water past the cuff. When a seal was achieved with a volume of air in the cuff less than cuff residual volume, wall pressure tended to be low (less than 35 torr) and cuff pressure closely approximated wall pressure. There was no relationship between cuff brands in the wall pressure required to effect a seal in the model. The authors conclude that intratracheal tubes should have cuffs with large residual volumes. This would permit some latitude in tube size selection while ensuring that a seal could be achieved before the cuff is inflated to its residual volume.

Use of deep intravenous sedation with propofol and the laryngeal mask airway during transesophageal echocardiography

OBJECTIVE To describe the use of either deep intravenous sedation with propofol or light sedation with midazolam and topical anesthesia during transesophageal echocardiography (TEE) and to report the incidence of respiratory complications and their management. DESIGN Retrospective study from March 2000 through August 2002. SETTING Single institution, specialized cancer center. PARTICIPANTS All patients undergoing TEE examination in the specified time period (n = 42). MAIN RESULTS Eight patients received light sedation and 34 patients received deep intravenous sedation with propofol. An airway event occurred in one patient in the light sedation group and in six patients in the deep sedation group. The patient in the light sedation group was managed with the use of a face-mask and a manual resuscitation bag. All airway events in the deep sedation group were managed successfully using the laryngeal mask airway (LMA). CONCLUSION Deep sedation with intravenous propofol can provide both excellent patient comfort and optimal conditions for TEE examination, particularly in patients who may require more lengthy procedures or in whom other techniques have failed. Although the incidence of respiratory depression was higher in patients receiving deep sedation with propofol than in patients who were lightly sedated (17.6% versus 12.5%, respectively), all six patients who had respiratory depression while under deep sedation with propofol were successfully ventilated using the LMA trade mark, without the need to remove the TEE probe and without terminating the examination prematurely. In contrast, in the one patient in the light sedation group who had respiratory depression, the TEE probe had to be removed to ventilate the patient via a face mask, and the procedure was cancelled.

Introduction: guidelines and advisory development

Since 1992, the American Society of Anesthesiologists has produced 12 evidence-based practice guidelines, 2 practice advisories, and 3 guideline updates. These documents have assisted anesthesiologists and practitioners in many other specialties. Their brevity, practicality, and ease of use, coupled with a thorough and systematic evaluation of the evidence have been instrumental in bringing together the science and practice of medicine. The application of formal evidence-collection processes for literature and opinion and efficient analytic evaluations combine with the experience and practical knowledge of clinicians to produce widespread application of the guidelines. The evidence-based process developed by the ASA has been found to be adaptable to a wide variety of issues relating to clinical practice. The goal is to systematically collect and evaluate evidence from multiple sources and apply it ina comprehensive manner to the guideline recommendations. The ASA guideline and advisory development process is continuing to evolve in response to changes in medical technology, research, and practice. By providing synthesized evidence from multiple sources and robust clinical recommendations the ASA offers the practice of anesthesiology, an invaluable bridge between science and clinical practice.

Catherization Techniques for Invasive Cardiovascular Monitoring

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