Predictors of outcome for patients with COPD requiring invasive mechanical ventilation.

INTRODUCTION: Accurate outcomes data and predictors of outcomes are fundamental to the effective care of patients with COPD and in guiding them and their families through end-of-life decisions. DESIGN: We conducted a retrospective cohort study of 166 patients using prospectively gathered data in patients with COPD who required mechanical ventilation for acute respiratory failure of diverse etiologies. RESULTS: The in-hospital mortality rate for the entire cohort was 28% but fell to 12% for patients with a COPD exacerbation and without a comorbid illness. Univariate analysis showed a higher mortality rate among those patients who required > 72 h of mechanical ventilation (37% vs 16%; p < 0.01), those without previous episodes of mechanical ventilation (33% vs 11%; p < 0.01), and those with a failed extubation attempt (36% vs 7%; p = 0.0001). With multiple logistical regression, higher acute physiology score measured 6 h after the onset of mechanical ventilation, presence of malignancy, presence of APACHE (acute physiology and chronic health evaluation) II-associated comorbidity, and the need for mechanical ventilation > or = 72 h were independent predictors of poor outcome. CONCLUSIONS: We conclude that among variables available within the first 6 h of mechanical ventilation, the presence of comorbidity and a measure of the severity of the acute illness are predictors of in-hospital mortality among patients with COPD and acute respiratory failure. The occurrence of extubation failure or the need for mechanical ventilation beyond 72 h also portends a worse prognosis.

Retching and termination of ventricular tachycardia. Report of two cases.

Two patients had ventricular tachycardia that reverted to sinus rhythm during retching. These cases are consistent with recent experimental and clinical observations that suggest the presence of significant vagal innervation of the ventricles and an important vagal effect on some ventricular arrhythmias.

Management of hip fractures in nursing home patients: to treat or not to treat?

Nursing home patients who sustain hip fractures have a much higher than average complication rate after surgical repair, and few ever walk again. Operation is not necessary to ensure the patient's survival in the postfracture period. The majority of these patients are better off managed without surgery. For patients with little or no chance to walk again, a nonsurgical treatment regimen in the nursing home is safer, more humane, and far less expensive than hospitalization.

Quantitative grip strength assessment as a means of evaluating muscle relaxation in mice.

The effects of various centrally acting drugs and some peripherally acting agents on the forelimb grip strength of CD-1 mice were explored. Forelimb grip strength was assessed by use of a strain gauge to measure the lateral pull force, in grams, exerted by mice as an index of muscle relaxation. The muscle relaxants, diazepam, midazolam, baclofen, methocarbamol, dantrolene sodium and the neuromuscular blocking agents, succinylcholine and pancuronium bromide, dose-dependently reduced forelimb grip strength. 2-Amino-7-phosphonoheptanoic acid (AP7), which has also been shown to have muscle relaxant effects, also reduced grip strength. Pentobarbital, ethanol, phencyclidine, ketamine and chlorpromazine reduced grip strength at doses which produced behavioral impairments. Lithium chloride, a toxic compound used to induce taste aversions, and clonidine, at doses which affect blood pressure, body temperature and locomotor activity, did not affect grip strength. In addition, stimulant doses of amphetamine and caffeine, but not of morphine, increased grip strength in a dose-dependent manner. These results extend previous findings and suggest that this forelimb grip strength procedure may be a useful screening test for the identification of the potential muscle relaxant properties of drugs.

A comparison of the anticonvulsant effects of competitive and non-competitive antagonists of the N-methyl-D-aspartate receptor.

The anticonvulsant activity of two competitive antagonists of the N-methyl-D-aspartate (NMDA) receptor, 2-amino-7-phosphonoheptanoic acid (APH) and 3-[2-carboxypiperazin-4-yl]-propyl-1-phosphonate (CPP), and two non-competitive NMDA antagonists, phencyclidine (PCP) and (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801), were compared in 4 models of induced seizures in mice. All 4 drugs protected against tonic extensor seizures induced by pentylenetetrazol (PTZ), by submaximal (15 mA) electroconvulsive shock (ECS) and by maximal (50 mA) ECS. Similar orders of potency (i.e., MK-801 greater than PCP greater than or equal to CPP greater than APH) were seen in each of the 3 seizure models. All 4 drugs failed to block clonic seizures induced by picrotoxin in the dose ranges that protected from tonic seizures. These data are consistent with other data demonstrating that competitive and non-competitive NMDA antagonists have similar pharmacologic effects. These results also support the suggestion that the anticonvulsant effects of competitive and non-competitive NMDA antagonists are mediated by the NMDA receptor-ionophore complex.

Anxiolytic-like effects of N-methyl-D-aspartate-associated glycine receptor ligands in the rat potentiated startle test.

Competitive and non-competitive NMDA receptor complex antagonists have been shown to be active in various models of anxiolytic activity. This study examined the effects of ligands at the NMDA receptor-associated glycine site and two competitive NMDA receptor antagonists on the fear-potentiated startle response model for anxiolytic activity. The results show that the NMDA receptor antagonists, 2-amino-7-phosphonoheptanoate (30 mg/kg) and 3-(2-carboxypiperazin-4-yl)propyl-1-phosphonate (3 mg/kg), the glycine receptor antagonist 7-chlorokynurenate (100 mg/kg), and the glycine receptor partial agonists 3-amino-1-hydroxy-2-pyrrolidinone ((+)-HA-966) (30 mg/kg), 1-aminocyclopropane carboxylate (200-500 mg/kg) and D-cycloserine (30-300 mg/kg) blocked the potentiated startle effect. These results extend the findings of earlier studies showing anxiolytic-like effects of NMDA antagonists and glycine receptor ligands by demonstrating their effectiveness in the rat potentiated startle paradigm. These results also demonstrate the anxiolytic potential of D-cycloserine.

Weaning from prolonged mechanical ventilation.

The development of weaning failure and need for PMV is multifactorial in origin, involving disorders of pulmonary mechanics and complications associated with critical illness. The underlying disease process is clearly important when discussing mechanisms of ventilator dependence; interventions therefore must be tailored to individual patients. Unfortunately, the main conclusion that can be drawn from the sum of the studies investigating patients on PMV to date is that an evidence-based approach to weaning is not possible and more research needs to be done. New studies need to incorporate severity-of-illness scores and an assessment of principal and comorbid conditions to allow for comparison of the findings from different centers. The best approach to a patient requiring PMV after exclusion of easily treatable conditions is not known. The literature regarding both acute and chronic cases suggests that a systematic approach to weaning involving the participation of multiple caregivers, including nurses, physicians, and respiratory, physical, and speech therapists facilitates liberation from MV. Although a gradual decrement in ventilator support would seem prudent, Scheinhorn et al have begun to identify a subpopulation of patients who can tolerate an acceleration of the weaning process. Given the known complications associated with MV, it is crucial that further research be performed to identify patients as soon as they are capable of breathing spontaneously. The literature demonstrates through multiple studies that satisfactory patient outcomes are attainable and can be achieved at LTAC facilities in a more cost-effective manner than in an ICU setting. The trend toward the concentration of patients into specialized regional weaning centers should facilitate the research process and continue to improve outcomes in this population.

Milacemide, a glycine prodrug, enhances performance of learning tasks in normal and amnestic rodents.

The N-methyl-D-aspartate receptor complex appears to play an important role in processes of learning and memory. The presence of a glycine modulatory site at this complex has recently been established and suggests that glycinergic neurotransmission may influence these cognitive functions. Increasing glycine concentrations in the brain by administration of a glycine prodrug, milacemide, is shown here to enhance performance of a shock-motivated passive avoidance task in rats, and to reverse drug-induced amnesia in a spontaneous alternation paradigm in mice. Prevention of the metabolism of milacemide to glycine by pretreatment with MAO-B inhibitors not only prevents the memory-enhancing effects of the drug, but appears to have a deleterious effect on memory formation suggesting an action of the prodrug itself on the brain. These studies indicate a role of glycinergic neurotransmission in memory processes, and support the therapeutic potential of glycinergic drugs in memory impairment.

The successful use of osseointegrated implants for the treatment of the recalcitrant periodontal patient.

This study reports the successful use of osseointegrated implants to replace teeth in patients whose periodontal disease has been categorized as recalcitrant. It includes partially and totally endentulous jaws. A total of 309 implants placed by two periodontists practicing in traditional office settings were included in the survey. Of the 132 mandibular implants, 4 failed, for a success rate of 97%; and 3 of the 177 maxillary implants failed, for a success rate of 98%. There were 21 implants placed in 1985; 38 in 1986 and 1987; 185 from 1988 to 1990; 42 in 1991; and 23 in 1992. The report includes 42 mandibular and 50 maxillary prostheses, none of which has failed. One female mandibular case was converted from 2 posterior free-standing to a full arch prosthesis when the anterior teeth failed periodontally. These results demonstrate that individuals with a strong susceptibility to periodontal disease can be treated successfully with osseointegrated implants.

Early career experiences of young periodontists.

Studies conducted in 1979 and 1984 suggested that young periodontists in the early eighties were faced with a variety of stresses and challenges not faced by their counterparts of previous generations. Among the changes observed was the fact that sharply increased numbers of younger periodontists were practicing in multiple locations. The present study focused on multiple location practice and on other early career experiences in periodontology. Multiple site practice appears to be an outgrowth of expanding group practices and the increased popularity of part-time associateship opportunities. Costs of establishing solo practice, as well as other factors, serve to encourage young specialists to seek such positions. Many specialists see this style of practice as one way to increase their market share, but stresses arising from multiple site practice include travel time and lack of continuity with patients. Thus far, younger periodontists remain satisfied with their careers, but the job market suggests that more and more periodontists will be practicing in multiple locations during the early years of their careers, thus prolonging stabilization of their economic and professional lives.

Practice styles in periodontics. II.

In 1980 the American Academy of Periodontology published the results of its first major survey of practice characteristics in the Journal of Periodontology. That first study arose from membership concerns about the lack of knowledge about career patterns of periodontists and, more specifically, about employment opportunities for graduating periodontists. Three years later, the Committee on Practice Styles and Opportunities in Periodontics was appointed to replicate the earlier study in order to provide information on recent changes in the practice of periodontics. This decision is commendable since few dental specialty organizations collect data from their membership which can be systematically compared to data from an earlier study. The Academy's Committee contacted David O. Born, PhD, a dental manpower specialist at the University of Minnesota and a technical advisor on the earlier study, for assistance in conducting a replication in 1984. Based on feedback on the first survey and on comments and suggestions from committee members, a revised questionnaire was developed. This questionnaire was, for the most part, a replication of the earlier survey instrument, although several problematic items were deleted or modified and new items, reflecting more recent concerns, were added. The revised questionnaire was distributed in the Spring of 1984 through two mailings to 2937 Active members and 798 Affiliate members. After unusable and undeliverable questionnaires were deleted from the returns, an effective response rate of 55% (N = 2082) was obtained. This report is based on the information supplied by those 2082 members. In the tables and text which follow, the figures reported at the national level refer to "Private practice" periodontists responding to the survey; Academy members who are a part of the Federal services (e.g., Military, Veterans' Administration, Indian Health Service, etc.) are tabulated separately as "District 8" data. While several members from foreign countries responded to the survey, their data have not been included since the information was too dispersed to permit conclusions to be drawn.

Relationship between crevicular aspartate aminotransferase levels and periodontal disease progression.

BACKGROUND: Aspartate aminotransferase (AST), an enzyme released from necrotic cells, has been identified in gingival crevicular fluid (GCF), and elevated levels are associated with periodontal tissue destruction. The aim of this study was to examine the relationship between elevated GCF levels of AST and periodontal disease progression. METHODS: Over a 12-month period, 8 to 10 interproximal sites in 41 periodontitis subjects (PS) and 15 healthy subjects (HS) were monitored. Clinical measurements included relative attachment level (RAL), probing depth, and bleeding on probing (BOP). Semiquantitative levels of GCF AST (< 800 microIU, > or = 800 microIU, and > or = 1,200 microIU) were determined using a chairside assay. At the 6- and 12-month visits, scaling and root planing and prophylaxis were performed in the PS and HS, respectively. Sensitivity, specificity, positive predictive values (PPV), and negative predictive values (NPV) were calculated for 2 diagnostic criteria (AST > or = 800 microIU, AST > or = 1,200 microIU) utilizing 4 thresholds of disease progression as determined by 2 methods (absolute change in relative attachment level and cumulative sum [CUSUM]). RESULTS: The percentage of sites exhibiting AST > or = 800 microIU, AST > or = 1,200 microIU, and BOP in the PS was significantly (P<0.02) lower at 6 and 12 months compared to baseline. The use of crevicular AST activity to monitor periodontal disease progression was associated with many false-positive results. Overall, low specificities, PPV, and odds ratios were demonstrated by the assay when using 2 diagnostic criteria and 4 thresholds of disease progression. The high NPV suggest that a negative AST test result was indicative of a periodontally stable site. CONCLUSIONS: These results demonstrate that elevated levels of AST were present at sites that did not subsequently exhibit disease progression. The high prevalence of AST-positive sites due to gingival inflammation diminished the test's ability to discriminate between progressive and stable, but inflamed, sites.

Comparison of manual and automated probing in an untreated periodontitis population.

Diagnosis of periodontal disease progression involves recording two probing attachment level measurements over an adequate time interval. A diagnostic instrument which exhibits less measurement variability allows for increased sensitivity and earlier disease detection. Traditionally, a manual probe with an occlusal stent of the cementoenamel junction (CEJ) as a reference landmark has been the method of choice. Automated probes that use an occlusal disk as the reference landmark have been developed as an alternative means of measure. The aim of this study was to compare the variability of these two probing methods. Four hundred eleven (411) interproximal sites in 46 untreated periodontitis patients were monitored by a single examiner over a 6-month period. Each site was measured on a monthly basis, first with an automated probe (AP) followed by a manual probe (MP) in combination with a custom-fabricated acrylic stent. Measurement variability of the two probing methods was also compared over a 7-day interval. The AP measurements were significantly more variable than the MP measurements (P < 0.001) when considering the variability between two passes at the same visit. Over the 6-month period, the MP measurements demonstrated significantly more variability than the AP measurements (P < 0.001). It was also noted that MP measurements exhibited more variability at sites with frequent bleeding during the 6 months of the study (P = 0.006). The results of this study demonstrate that AP may have less variability of attachment level measurements over a 6-month period and may be less influenced by local inflammatory changes. However, future comparison studies should include multiple examiners to reduce examiner bias and should alternate the probing method to reduce bias created by local tissue changes from multiple probings.

The successful application of osseointegrated implants to the posterior jaw: a long-term retrospective study.

This long-term study has demonstrated the successful use of osseointegrated implants to replace posterior teeth in the partially dentate patient. A total of 1,203 Nobelpharma implants placed by two periodontists practicing in traditional office settings were included in the survey. Of the 551 implants placed in the mandible, 25 failed, for a success rate of 95.5%. Of the 247 mandibular prostheses fabricated for 200 mandibles, 8 failed, for a prosthesis stability rate exceeding 97%. Of the 652 implants placed in the maxilla, 31 failed, for a success rate of 95.2%. Of the 250 maxillary prostheses fabricated for 193 maxillae, 2 failed, for a success rate exceeding 99%. The results compare favorably to previous reports in terms of implant survival and stability.

A new animal model for maxillary sinus floor augmentation: evaluation parameters.

This study describes a novel animal model of the maxillary sinus floor augmentation procedure used to assess bone formation during 12 weeks in response to a recombinant human bone morphogenetic protein-2 (rhBMP-2)/absorbable collagen sponge (ACS) sinus implant. A buffer-ACS implant was used as a control. Animal response was monitored using computerized tomography and physical, hematologic, gross pathologic, and histologic evaluations. The rhBMP-2/ACS implants maintained a relatively constant size postsurgery and showed a time-dependent increase in mineralization. The buffer/ACS control implants failed to mineralize and were resorbed by 4 weeks. The model served effectively and without complication. Results indicate rhBMP-2/ACS implants deserve consideration as alternatives to traditional grafting procedures.

Correlation of peri-implant health and aspartate aminotransferase levels: a cross-sectional clinical study.

At present, there are no diagnostic tools that permit early detection of peri-implantitis. The purpose of this cross-sectional study was to evaluate the correlation of aspartate aminotransferase (AST) levels with traditional periodontal clinical parameters around dental implants, since AST has been associated with destruction of cardiac, hepatic, and periodontal tissues. Twenty healthy volunteers with 59 implants were recruited from the Harvard School of Dental Medicine clinics. Clinical parameters evaluated included: AST level, probing depth (mm), Gingival Index (0, 1, 2, or 3), and bleeding on probing (0 or 1). Utilizing the site or implant as the unit of measure, the authors found a statistically significant association of increased AST activity with positive bleeding on probing, increased probing depth, and increased Gingival Index. No statistical correlations were found between clinical indices and increased AST levels when the results were examined on an individual patient basis. This cross-sectional study was able to demonstrate a statistical correlation between diseased clinical periodontal parameters and elevated AST levels.

Wound healing around endosseous implants in experimental diabetes.

Wound healing has been shown to be altered in diabetes mellitus. The aim of this study was to identify the effects of streptozotocin-induced diabetes on osseointegration. Diabetes was induced in 40-day-old rats by intraperitoneal injection of 70 mg per kg streptozotocin. At 14 days postinjection, implants were placed in the femora of 10 diabetic and 10 age-matched normal rats. Animals were sacrificed at 28 and 56 days following implantation. Histometric results indicated that the quantity of bone formation was similar for diabetic and control animals (P > .05). However, less bone-implant contact was observed for diabetic compared to control animals at both 28 and 56 days (P < .0001). This study demonstrates that the process of osseointegration is affected by streptozotocin-induced diabetes.

Diagnosing periodontal diseases.

At present, the diagnosis of periodontal disease requires a clinical evaluation of the patient including visual findings, the use of the periodontal probe, and radiographs. No test is available to evaluate disease activity. In specific cases, adjunctive procedures may also be useful. The identification of pathogenic microorganisms may aid in evaluating the periodontal status of special patients. However, these are not required for an adequate diagnosis of the common adult form of chronic periodontitis.

Success of children with cochlear implants in mainstream educational settings.

The availability of cochlear implant technology has made mainstreaming a more reachable social and academic goal for profoundly deaf children. Traditionally, the profoundly deaf child has required more self-contained education. It has been the hard-of-hearing child who reached the mainstream education classroom during the elementary years. Cochlear implant recipients, implanted early and receiving appropriate educational services that maximize learning across all domains, have shown a significant trend toward moving from a more self-contained to a less restrictive educational environment. Children with implants are making these transitions earlier than the larger majority of profoundly deaf children using traditional amplification.

Treatment of Class II furcations with autogenous bone grafts and e-PTFE membranes.

This article reports a successful clinical regimen of treatment for the Class II furcation defect. Twenty-eight patients with molar teeth demonstrating Class II furcations were treated with regenerative therapy with the goal of regenerating lost interradicular periodontium. The treatment selected included scaling and root planing, surgical flap design that would enable the flap to completely cover the surgical site, complete enucleation of granulation tissue, tetracycline root conditioning, a particulate autogenous bone graft, and an expanded polytetrafluoroethylene (e-PTFE) membrane. Of the twenty-eight consecutive patients treated, twenty-five demonstrated no postoperative clinical evidence of furcation invasion, for a success rate of 89%. Eleven sites were reopened 8 to 9 months postsurgical and presented complete furcation fill with a hard, bone-like tissue. Three teeth were judged to be failures because clinical assessment revealed persistent furcation invasion. The absence of histologic evidence precludes the presumption that complete periodontal regeneration occurred.