A Comparison of the Mallampati evaluation in neutral or extended cervical spine positions: a retrospective observational study of >80 000 patients.

BACKGROUND: The Mallampati examination is a standard component of an airway risk assessment. Existing evidence suggests that cervical spine extension improves the predictive power of the Mallampati examination for detecting difficult laryngoscopy and tracheal intubation, but a comparative effectiveness study has not been conducted. METHODS: The extended Mallampati examination (EMS) was introduced to the standard preoperative airway assessment, in addition to the standard Modified Mallampati examination (MMP). This study compared the accuracy of both Mallampati examinations on the prediction of difficult laryngoscopy, tracheal intubation, and bag mask ventilation. Univariate and adjusted analyses were performed. RESULTS: 80 801 patients with recorded MMP and EMS, and subsequent glottic view obtained during direct laryngoscopy, were examined. There was increased specificity (88.7% cf. 81.9%) but reduced sensitivity (33.3% cf. 45.7%) in the detection of difficult direct laryngoscopy with use of the EMS. The area under the receiver operating characteristic curve of each test performed in combination with other airway predictors for the models predicting difficult laryngoscopy was 0.740 (95% CI 0.731-0.753) for MMP and 0.739 (95% CI 0.729-0.752) for EMS. The area under the receiver operating characteristic curve of each test, performed in combination with other airway predictors for the models predicting difficult intubation was 0.699 (95% CI 0.688-0.711) for MMP and 0.695 (95% CI 0.683-0.707) for EMS. CONCLUSIONS: This retrospective observational study demonstrates that cervical extension improves the specificity but decreases sensitivity of Mallampati examination. The Mallampati evaluation should be performed with the cervical spine in the neutral position to maximize test sensitivity.

Cost-effectiveness of adjuvant radiotherapy in intermediate risk endometrial cancer.

OBJECTIVES: Endometrial cancer is the most common gynecologic malignancy in the United States. Adjuvant radiotherapy in patients with intermediate risk disease (stage IB, IC, and occult stage II) is controversial. Despite no proven survival advantage, a significant number of women undergo this treatment annually. The purpose of this study was to compare the estimated health and economic outcomes for adjuvant whole pelvic radiotherapy to no treatment with salvage therapy for recurrence. METHODS: A decision analytic model was created to estimate the costs of adjuvant pelvic radiotherapy versus no adjuvant radiotherapy in patients with intermediate risk endometrial cancer. Data used was gathered from published literature and institutional data on costs. The model incorporates complications, recurrence rates, treatment of recurrence, and survival in each group. RESULTS: In the base case analysis, adjuvant pelvic radiation reduced the recurrence rate by 50%. Cost-effectiveness as measured by cost per recurrence prevented was highly sensitive to the probability of recurrence and the efficacy of adjuvant therapy. In our model the mean costs of Strategy 1 with observation and treatment reserved until the time of recurrence would be $5016. In contrast the mean cost of Strategy 2 which incorporated adjuvant radiotherapy would be $21,159. Cost per recurrence prevented based on the incremental cost-effectiveness is thus $225,215. In the highest risk subgroup, using the upper limit of the 90% confidence limit of efficacy seen in GOG Protocol 99, cost/recurrence prevented was approximately $50,000. Results did not differ when using parameters solely from GOG 99 or PORTEC. CONCLUSIONS: Although adjuvant pelvic radiation does not appear to improve survival for intermediate risk endometrial cancer patients, it does prevent recurrences, at a net positive cost compared to no therapy. Data are not currently available to incorporate quality of life information into cost-effectiveness analyses. Obtaining such data would allow cost/quality-adjusted life year gained to be estimated. This information is necessary to determine if the extra costs of adjuvant radiotherapy in patients with intermediate risk endometrial cancer are acceptable by current health care policy standards.

Use of trastuzumab in the treatment of metastatic endometrial cancer.

Systemic therapy of metastatic endometrial cancer is relatively ineffective. Response rates to chemotherapy and hormonal therapy in published studies range from 11% to 57%, but most responses are partial and of limited duration. In this case, we present a 76-year-old woman with stage IIIA endometrial adenocarcinoma who was initially treated with surgery and pelvic radiation. She developed multiple pulmonary metastases. She was treated with weekly paclitaxel chemotherapy. Immunostaining revealed that the primary endometrial cancer overexpressed HER-2/neu. Trastuzumab was added to the regimen, and a dramatic partial response was achieved. After a second pulmonary relapse following discontinuation of prior therapy, she was again successfully treated with trastuzumab in combination with paclitaxel and then docetaxel. Therefore, trastuzumab may be a useful adjuvant to taxane-based chemotherapy in some patients with metastatic endometrial cancers that overexpress HER-2/neu.

Carotid duplex with contralateral disease: the influence of vertebral artery blood flow.

The hemodynamic effect of severe contralateral internal carotid (ICA) disease may result in overestimation of ipsilateral stenosis by duplex ultrasound (DU). This study examines the role of the vertebral artery system (VAS) on duplex results in patients with severe carotid disease. A retrospective study of 110 patients who underwent carotid endarterectomy (CEA) between January 1, 1995 and January 31, 1998 was performed. All patients had a preoperative and postoperative DU within 6.5 months of each other and a preoperative magnetic resonance angiogram or conventional angiogram. Duplex categories of stenosis were mild (0-49%), moderate (50-79%), and severe (80-99%). Pre- and postoperative values for ICA peak systolic velocity (PSV), end diastolic velocity (EDV), and ICA-to-common carotid artery (CCA) ratio were recorded. Paired t-tests were used to assess significant changes within groups and independent t-tests were used to compare changes between groups. Sixty-seven patients had a normal VAS and 43 patients had an abnormal VAS. Patients with an abnormal VAS had significantly greater decreases in EDV after contralateral CEA. In the abnormal VAS group, there was a higher incidence (23.2% vs. 16.4%) of ipsilateral overestimation of stenosis by duplex and a greater incidence (20.9% vs. 10.4%) of postoperative decrease in stenosis following contralateral CEA than in the normal VAS group. Patients who underwent CEA for severe stenosis versus moderate stenosis had significant postoperative decreases in ipsilateral PSV, EDV, and ICA/CCA ratio. Severe contralateral stenosis patients with an abnormal VAS had a significant decrease in EDV compared to patients with a normal VAS. Vertebral artery blood flow contributes significantly to the "hemodynamic effect" of carotid disease identified by duplex.

Familial carotid body tumors: a closer look.

PURPOSE: A family spanning three generations with a history of familial carotid body tumors (CBTs) was studied, and previously proposed hypotheses of tumor characteristics and genetic mode of transmission were addressed. METHODS: Clinically occult lesions in adult subjects were detected by means of high-resolution computed tomography. RESULTS: A 60% incidence of bilaterality of CBTs associated with multiple paragangliomas was noted in the family studied. The genetic mode for CBTs in this family was not simple autosomal dominant transmission and appeared to be paternally directed with complete penetrance. CONCLUSION: In patients with familial CBTs, high-resolution computed tomography is recommended for early screening as a means of prompting diagnosis and definitive treatment, an approach that minimizes morbidity and facilitates surgical excision.

Resident rights. Knowledge of and implementation by nursing staff in long-term care facilities.

In this study, we assessed the differences between certified nursing assistants' (CNAs) and nurses' (RNs and LPNs) level of knowledge and perceived implementation of resident rights. The CNAs and nurses responded to a series of 11 scenarios representing rights such as privacy, choice, and respect. Their responses suggested that although they knew what the appropriate response to the situation was, it was not the typical response to that type of situation within their facilities. Implications for teaching and applying resident rights are discussed.

Repair of injured vertebral artery in anterior cervical procedures.

STUDY DESIGN: A case report of treatment of injury to the vertebral artery in anterior cervical procedures is presented with a review of the literature. OBJECTIVES: The feasibility of direct surgical repair is suggested. SUMMARY OF BACKGROUND DATA: Currently, ligation or tamponade is accepted as the treatment of injury to the vertebral artery in anterior cervical surgery. Significant morbidity can result from this method. Direct repair should eliminate this morbidity. METHODS: A report is presented of a patient who sustained injury to the vertebral artery, and the technique of repair is discussed. The literature was reviewed. RESULTS: The outcome was successful regarding both repair and the primary procedure. CONCLUSIONS: Although it is impossible to make a recommendation based on a single incident, this technique is believed to minimize postoperative sequelae that can be associated with occlusion of the vertebral artery.

Site-directed mutagenesis of a predicted cation binding site of Na, K-ATPase.

Chemical modification and proteolytic digestion studies have identified a transmembrane glutamic acid residue (E953) of the alpha subunit of the pig kidney Na, K-ATPase as a possible cation binding site [Goldshleger et al. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 6911-6915]. In addition, an adjacent glutamate (E954) is conserved in all species and isoforms and may also be involved in cation binding. To further explore the role of these residues in ion transport, we have utilized a mutagenesis-expression strategy. This approach avoids the introduction of a large chemical moiety into the protein and allows specific amino acid substitutions to be introduced. Glutamic acid residues 955 and 956 of the rat alpha-1 subunit (corresponding to glutamates 953 and 954 of the pig kidney Na, K-ATPase) were replaced separately and together using site-directed mutagenesis of the rat alpha-1 cDNA. The mutant cDNAs were expressed in ouabain-sensitive HeLa cells. This system makes it possible to rapidly identify amino acid substitutions which significantly impair enzyme function, as substitutions which do not affect enzyme activity will yield colonies in the presence of ouabain, while substitutions which severely impair function will prevent or limit growth of the ouabain-sensitive HeLa cells. The amino acid replacements (E955Q, E956Q, E955Q-E956Q, E955D-E956D) all resulted in the growth of ouabain-sensitive cells, demonstrating that the modified Na, K-ATPase in each case was functional. To further study the altered enzymes, ouabain-resistant colonies were isolated and expanded into stable cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)

Chimeric rat Na,K-ATPase alpha 1/alpha 3* isoforms. Analysis of the structural basis for differences in Na+ requirements in the alpha 1 and alpha 3* isoforms.

Na,K-ATPase molecules containing the alpha 1, alpha 2*, and alpha 3* isoforms expressed in HeLa cells exhibit a two- to threefold difference in their K0.5 for Na+ (alpha 1 = alpha 2* < alpha 3*). To investigate the structural basis for this difference, chimeric alpha 1/alpha 3* isoform cDNAs were constructed and expressed in HeLa cells. Na,K-ATPase containing each alpha isoform chimera was analyzed for its Na+ dependence properties. Results of these experiments do not reveal a region in the alpha 1 or alpha 3* isoform that is clearly responsible for the apparent affinity for Na+. It is possible that molecular interactions involving amino acids that span virtually the entire Na,K-ATPase molecule contribute to the determination of this parameter.

Isoforms of the alpha subunit of Na,K-ATPase and their significance.

Recent studies of the Na,K-ATPase have demonstrated that multiple isoforms of both the alpha and beta subunits exist and that these are expressed in a tissue and developmental specific manner. In the case of the alpha subunit, there are three known isoforms, alpha 1, alpha 2 and alpha 3. We have examined adult human heart for the presence of these isoforms and found that all three exist in approximately equal amounts. This is in contrast to the adult rat heart which contains only alpha 1 and alpha 2 isoforms. The difference in abundance of various isoforms in various tissues could result from the necessity to express Na,K-ATPase with different properties at various developmental stages or in specific cell types. For example, enzymes with differences in Na+ or K+ affinity or the ability to respond to various effector molecules may be required. Alternatively, the presence of three isoforms may simply result from the triplication of the alpha subunit gene and the divergence of expression of these genes during evolution. In this case the isozymes would not confer a specific function to the Na,K-ATPase. In order to provide information with respect to these two alternatives, cell lines producing rat alpha 1, alpha 2 and alpha 3 were developed and the enzymatic properties of the resulting enzyme determined. The results indicate that Na,K-ATPase carrying the alpha 1 are alpha 2 isoforms are fairly similar while enzyme with the alpha 3 isoform differs in its apparent affinity for sodium. The K0.5 for Na+ is approximately three fold lower for this isoform.(ABSTRACT TRUNCATED AT 250 WORDS)

Avoiding complications in arterial surgery.

Our approach to vascular surgery is to recognize and contemplate perioperative complications and devise strategies to avoid them. These strategies are detailed in several of the major areas of arterial surgery. It is far easier to avoid complications than to deal with them when they occur. This is especially true for some complications in vascular surgery, such as intraoperative or postoperative cerebrovascular accident, atheroembolic complications, or distal thrombosis in lower-extremity reconstruction, that may result in either irreversible morbidity or death.

Comparison of the substrate dependence properties of the rat Na,K-ATPase alpha 1, alpha 2, and alpha 3 isoforms expressed in HeLa cells.

The role of multiple isoforms for the alpha subunit of Na,K-ATPase is essentially unknown. To examine the functional properties of the three alpha subunit isoforms, we developed a system for the heterologous expression of Na,K-ATPase in which the enzymatic activity of each isoform can be independently analyzed. Ouabain-resistant forms of the rat alpha 2 and alpha 3 subunits were constructed by site-directed mutagenesis of amino acid residues at the extracellular borders of the first and second transmembrane domains (L111R and N122D for alpha 2 and Q108R and N119D for alpha 3). cDNAs encoding the rat alpha 1 subunit, which is naturally ouabain-resistant, and rat alpha 2 and alpha 3, which were mutated to ouabain resistance (designated rat alpha 2* and rat alpha 3*, respectively) were cloned into an expression vector and transfected into HeLa cells. Resistant clones were isolated and analyzed for ouabain-inhibitable ATPase activity in the presence of 1 microM ouabain, which inhibits the endogenous Na,K-ATPase present in HeLa cells (I50 approximately equal to 10 nM). The remaining activity corresponds to Na,K-ATPase molecules containing the transfected rat alpha 1, rat alpha 2*, or rat alpha 3* isoforms. Utilizing this system, we examined Na+, K+, and ATP dependence of enzyme activity. Na,K-ATPase molecules containing rat alpha 1 and rat alpha 2* exhibited a 2-3-fold higher apparent affinity for Na+ than those containing rat alpha 3* (apparent KNa+ (millimolar): rat alpha 1 = 1.15 +/- 0.13; rat alpha 2* = 1.05 +/- 0.11; rat alpha 3* = 3.08 +/- 0.06). Additionally, rat alpha 3* had a slightly higher apparent affinity for ATP (in the millimolar concentration range) compared with rat alpha 1 or rat alpha 2* (apparent K0.5 (millimolar): rat alpha 1 = 0.43 +/- 0.12; rat alpha 2* = 0.54 +/- 0.15; rat alpha 3* = 0.21 +/- 0.04) and all three isoforms has similar apparent affinities for K+ (apparent KK+: rat alpha 1 = 0.45 +/- 0.01; rat alpha 2* = 0.43 +/- 0.004; rat alpha 3* = 0.27 +/- 0.01). This study represents the first comparison of the functional properties of the three Na,K-ATPase alpha isoforms expressed in the same cell type.

Abdominal aortic aneurysms.

Modern surgical techniques permit repair of abdominal aortic aneurysms and prevent eventual rupture, with a mortality rate of only a few percent. Coronary heart disease is the chief cause of death, depriving the patient of an assumed improved life expectancy after successful operation for aneurysm. Therefore, aggressive preoperative cardiac evaluation, including coronary arteriography and perhaps more protective myocardial revascularization procedures, is indicated.

Peripheral aneurysms.

Peripheral atherosclerotic aneurysms occur primarily in elderly men. Major complications are arterial thromboembolism with ischemia of the limb and, rarely, rupture of the aneurysm. Vascular reconstruction is associated with a low mortality, and operation is recommended. These aneurysms are often associated with arterial ectasia at other locations. The presence of peripheral atherosclerotic aneurysms always requires a search for other peripheral aneurysms, particularly in the abdominal aorta.

Aneurysm formation in distal saphenous vein bypass grafts as a cause of graft failure.

Aneurysms of a reversed saphenous vein femoropopliteal bypass graft developed in two patients. In both patients, the aneurysm led to thrombosis and occlusion of the graft. One graft was reopened by intraarterial thrombolysis followed by local graft revision; the other required complete regrafting. This uncommon cause of graft occlusion should be considered before thrombolysis.

Chronic rupture of abdominal aortic aneurysms.

Chronic rupture of the aorta is a rare condition. In this report, the presentation, diagnosis, and management of two patients with this complication is described. Chronic rupture may occur without hypotension and may mimic several other conditions. CT scans are superior to ultrasound in diagnosis and evaluation. Emergency repair is not necessary in clinically stable patients and careful preoperative planning may diminish morbidity and mortality.