Pressure-controlled ventilation improves oxygenation during laparoscopic obesity surgery compared with volume-controlled ventilation.

BACKGROUND: We compared pressure and volume-controlled ventilation (PCV and VCV) in morbidly obese patients undergoing laparoscopic gastric banding surgery. METHODS: Thirty-six patients, BMI>35 kg m(-2), no major obstructive or restrictive respiratory disorder, and Pa(CO(2))<6.0 kPa, were randomized to receive either VCV or PCV during the surgery. Ventilation settings followed two distinct algorithms aiming to maintain end-tidal CO(2) (E'(CO(2))) between 4.40 and 4.66 kPa and plateau pressure (P(plateau)) as low as possible. Primary outcome variable was peroperative P(plateau). Secondary outcomes were Pa(O(2)) (Fi(O(2)) at 0.6 in each group) and Pa(CO(2)) during surgery and 2 h after extubation. Pressure, flow, and volume time curves were recorded. RESULTS: There were no significant differences in patient characteristics and co-morbidity in the two groups. Mean pH, Pa(O(2)), Sa(O(2)), and the Pa(O(2))/Fi(O(2)) ratio were higher in the PCV group, whereas Pa(CO(2)) and the E'(CO(2))-Pa(CO(2)) gradient were lower (all P<0.05). Ventilation variables, including plateau and mean airway pressures, anaesthesia-related variables, and postoperative cardiovascular variables, blood gases, and morphine requirements after the operation were similar. CONCLUSIONS: The changes in oxygenation can only be explained by an improvement in the lungs ventilation/perfusion ratio. The decelerating inspiratory flow used in PCV generates higher instantaneous flow peaks and may allow a better alveolar recruitment. PCV improves oxygenation without any side-effects.

[European normative recommendations for medical gas pipeline systems]. / Normalisation européenne et systèmes de distribution de gaz médicaux.

Several recent decisions have been made in order to increase the security of medical gases delivery in French hospitals. These different changes affect: 1) the hospital itself with the creation of working groups in charge of both monitoring and maintenance of gases networks; 2) the pharmaceutical regulation with promotion of several gases to the status of drugs or need of CE marking for the whole gas network. European rules onset required to give up French former norms (NF) to the profit of "NF EN" rules. Nevertheless, the new norm NF EN 737-3 which concerns medical gases distribution systems does not affect principal clauses of the previous NF S 90-155. It introduces new elements allowing to deploy two types of medical gases networks: the double pressure level used in France and the single pressure level used in the rest of Europe. This new norm, which attempts to harmonize alarm control systems in both types of networks, suffers from important limitations describing the double pressure level systems. Lastly, the final checking proposed by this new norm is very different from the previous one, and is likely to be problematic for the final users within the hospital.

Main risk factors for nephropathy in type 2 diabetes mellitus are plasma cholesterol levels, mean blood pressure, and hyperglycemia.

BACKGROUND: The control of hyperglycemia is of major importance in the treatment of patients with type 1 diabetes mellitus. However, there is no consensus about the required degree of metabolic control in patients with type 2 diabetes mellitus and about the role of hyperglycemia in diabetic nephropathy and in the development of atherosclerosis in relation to other risk factors. PATIENTS AND METHODS: A prospective, long-term follow-up study was conducted on 574 patients, aged 40 to 60 years, with recent onset of type 2 diabetes mellitus. Patients were initially normotensive and had normal renal function and a normal urinary albumin excretion rate (<30 mg/24 h). The patients were followed up for 2 to 9 years (mean +/- SD, 7.8 +/- 0.9 years). Levels of hemoglobin A1c and plasma lipids, mean blood pressure, and body mass index (calculated as the weight in kilograms divided by the square of the height in meters) were determined periodically. Cigarette smoking and socioeconomic status were recorded. Renal status was evaluated by the logarithm of the final urinary albumin excretion rate and by the decline in reciprocal creatinine values. Definite clinical events including death, nonfatal myocardial infarction, angina pectoris, congestive heart failure, and peripheral vascular disease were recorded. RESULTS: At the end of the study the urinary albumin excretion rate remained normal (<30 mg/24 h) in 373 patients (65%), 111 (19%) had microalbuminuria (30-300 mg/24 h), and 90 (16%) had overt albuminuria (>300 mg/24 h). Logistic regression models demonstrated that the correlation between hemoglobin A1c levels and the risk of albuminuria is exponential. Multiple logistic regression analysis indicated that levels of total cholesterol, mean blood pressure, and hemoglobin A1c were the main factors associated with the decrease in renal function and with the increase in albuminuria. The combination of values higher than the 50th percentile of all 3 factors defined a high-risk patient population. These high-risk patients had an odds ratio of 43 (95% confidence interval, 25-106) for microalbuminuria and 15 (95% confidence interval, 9-25) for clinical events related to arteriosclerosis compared with the rest of the group. Low levels of high-density lipoprotein, body mass index, cigarette smoking, low socioeconomic status, and male sex were all significantly associated with diabetic nephropathy, as well as with the manifestations of arteriosclerosis. CONCLUSIONS: The combination of blood pressure values in the high-normal range with moderately elevated levels of total cholesterol and hemoglobin A1c defines a high-risk group for the progression to diabetic nephropathy and for clinical events related to arteriosclerotic cardiovascular disease.

Organizational and financial characteristics of health plans: are they related to primary care performance?

BACKGROUND: Primary care performance has been shown to differ under different models of health care delivery, even among various models of managed care. Pervasive changes in our nation's health care delivery systems, including the emergence of new forms of managed care, compel more current data. OBJECTIVE: To compare the primary care received by patients in each of 5 models of managed care (managed indemnity, point of service, network-model health maintenance organization [HMO], group-model HMO, and staff-model HMO) and identify specific characteristics of health plans associated with performance differences. METHODS: Cross-sectional observational study of Massachusetts adults who reported having a regular personal physician and for whom plan-type was known (n = 6018). Participants completed a validated questionnaire measuring 7 defining characteristics of primary care. Senior health plan executives provided information about financial and nonfinancial features of the plan's contractual arrangements with physicians. RESULTS: The managed indemnity system performed most favorably, with the highest adjusted mean scores for 8 of 10 measures (P<.05). Point of service and network-model HMO performance equaled the indemnity system on many measures. Staff-model HMOs performed least favorably, with adjusted mean scores that were lowest or statistically equivalent to the lowest score on all 10 scales. Among network-model HMOs, several features of the plan's contractual arrangement with physicians (ie, capitated physician payment, extensive use of clinical practice guidelines, financial incentives concerning patient satisfaction) were significantly associated with performance (P<.05). CONCLUSIONS: With US employers and purchasers having largely rejected traditional indemnity insurance as unaffordable, the results suggest that the current momentum toward open-model managed care plans is consistent with goals for high-quality primary care, but that the effects of specific financial and nonfinancial incentives used by plans must continue to be examined.

Inhaled nitric oxide as a therapy for pulmonary hypertension after operations for congenital heart defects.

Seventeen infants were treated with inhaled nitric oxide for critical pulmonary artery hypertension after operations for congenital heart defects. In all 17 patients conventional medical therapy consisting of hyperventilation, deep sedation/analgesia, and correction of metabolic acidosis had failed. All children were monitored with a transthoracic pulmonary artery catheter inserted at operation. Pulmonary artery hypertension was defined as an acute rise in pulmonary pressure associated with a decrease in oxygen arterial or venous saturation. After failure of conventional medical therapy, 20 ppm of inhaled nitric oxide was administered to the patient. In all patients the pulmonary pressures decreased (mean pulmonary arterial pressure decreased by -34% +/- 21%) without significant change in systemic arterial pressure, whereas the oxygen arterial saturation and oxygen venous saturation increased by 9.7% +/- 12% and 37% +/- 28%, respectively. Fifteen children were discharged from the intensive care unit at 10 +/- 6 days (range 3 to 26 days) and two died. This study demonstrates that inhaled nitric oxide exerts a selective pulmonary vasodilation without decreasing systemic arterial pressure in children with congenital heart disease. The increased values of mixed venous oxygen saturation and urinary output suggest that this selective lowering of pulmonary vascular resistance improved the overall hemodynamics. The potential toxic effects of nitric oxide and nitrogen dioxide necessitate careful consideration of the risks and benefits of inhaled nitric oxide therapy.

Comparative haemodynamic effects of dopamine and dobutamine in septic shock.

Septic shock associated with depressed myocardial function generally requires the use of catecholamine. Currently dopamine is often selected. Dobutamine is a newly developed catecholamine which has been shown to be of value in severe cardiomyopathic disease. The aim of this work was to determine the most appropriate drug by comparing haemodynamic responses to dopamine and dobutamine in 19 studies carried out in 11 patients with septic shock and heart failure. Cardiac index increased siliarly with dopamine and dobutamine (33%), as did stroke volume (respectively 26.4 and 25%). Arterial pressure increased by 17% with dopamine whereas it did not significantly change with dobutamine due to reduction in vascular resistance of 19%. Dobutamine decreased filling pressure, either right (14%) of left (28%) whilst they slightly but unsignificantly increased with dopamine. Pulmonary shunting increased more with dopamine (47%) than with dobutamine (16%), but PaO2 remained constant with both. Since septic shock is characterized by lowered arterial pressure and vasodilatation it is concluded that effects of dopamine on capacitance and resistance vessels make this drug more suitable. In addition it selectively increases renal blood flow. Nevertheless dobutamine could be appropriate, in case of very high filling pressures, severe peripheral vasoconstriction, marked pulmonary shunting and in some cases where dopamine becomes ineffective.

An analysis of the diagnostic methods for acute pulmonary embolism.

In spite of numerous sophisticated investigative procedures, acute pulmonary embolism (PE) is very frequently misdiagnosed. In order to improve the diagnostic approach to PE, the sensitivity and specificity of the commonly used methods were reviewed in a group of 421 patients with angiographically proved PE without associated cardio-pulmonary disease. The specificity of diagnostic procedures was, by decreasing order: positive pulmonary angiography (to affirm) = negative perfusion lung scan (to eliminate) greater than chest X-ray much greater than clinical symptoms, positive perfusion lung scan, ECG, blood gas, serum enzymes.

Inflammatory pseudotumors of the spleen.

Inflammatory pseudotumors are uncommon benign lesions that have been found in numerous organ systems. However, their appearance within the spleen is decidedly rare. Grossly, pseudotumors appear as well-circumscribed, encapsulated masses, while microscopic examination reveals a polymorphous inflammatory cell infiltrate occurring variably with granulomatous reaction, fibrosis, and cell necrosis. Because they often present either as unexplained, asymptomatic masses or with vague constitutional symptoms, splenic inflammatory pseudotumors can raise suspicion for a primary splenic neoplasm, such as lymphoma. Splenectomy is the treatment of choice.

The effect of empiric and prophylactic treatment with fluconazole on yeast isolates in a surgical trauma intensive care unit.

OBJECTIVE: To assess the effect of aggressive antifungal prophylaxis and empiric antifungal therapy using fluconazole on the mycotic microbiology and associated infectious complications in a surgical intensive care unit. DESIGN: Retrospective review of a cohort of critically ill surgical patients treated during an 11-month period. SETTING: Surgical intensive care unit, university hospital, state-designated level I trauma center. PATIENTS: All patients treated with fluconazole during the study. MAIN OUTCOME MEASURES: Positive fungal cultures obtained after commencement of antifungal prophylaxis or antifungal treatment with fluconazole. Overall and infectious mortality rates for patients with positive cultures were also measured. RESULTS: Of 72 surgical patients who were treated with fluconazole; 16 (22%) had secondary mycoses. Fourteen (88%) of these patients were receiving fluconazole as antifungal prophylaxis or as empiric treatment of suspected but unproved infection. The predominant organisms isolated from these 16 patients were Candida glabrata (41%) and Candida parapsilosis (41%). Overall mortality for this group was 44%, and infectious mortality was 38%. The infectious mortality rate was significantly higher than the rate found in patients who were successfully treated with fluconazole for primary mycoses, and who did not have secondary infections with resistant organisms (mortality, 9%; P < .01, chi 2). CONCLUSIONS: Emergence of resistant species after treatment with fluconazole does occur in surgical patients, and suggests that the development of a secondary fungal infection with a resistant organism may be associated with a poor prognosis.

A rare complication of splenic artery aneurysm. Mesenteric steal syndrome.

Splenic artery aneurysms are relatively common lesions that remain asymptomatic in the vast majority of patients. The commencement of symptoms is generally a morbid development because it frequently heralds either frank rupture or an erosive process that involves neighboring structures. Erosion into the splenic vein has been reported but is extremely rare. When this event occurs, the central arteriovenous fistula almost inevitably leads to a dramatic increase in portal venous pressures, which may subsequently be manifested as upper gastrointestinal tract hemorrhage. Herein, we report an unusual case of splenic artery aneurysm that was complicated by arteriovenous fistula formation in which high flow through the central splenic shunt led to the development of nontransmural small-bowel ischemia due to a mesenteric steal syndrome, which presented as acute lower gastrointestinal tract hemorrhage. Diagnostic modalities and therapeutic interventions used in this case are detailed, followed by a brief review of the pertinent literature.

Preliminary assessment of a scientific curriculum in a surgical residency program.

A structured, basic science curriculum was instituted for surgical residents of the University of Connecticut (Farmington) Integrated Residency Program during the 1990-1991 academic year in concordance with American Board of Surgery guidelines. The impact of the new program was measured by comparing performance on monthly basic science examinations, the in-training examination, and "mock" oral examinations for the 1990-1991 academic year with that of the preceding academic year. While monthly examination scores improved for the entire group of residents (67.7 vs 64.6), in-training and oral examination scores did not change significantly. Categorical residents generally demonstrated superior performance and greater improvement than did preliminary residents. Data analysis suggested that the new curriculum was an effective educational device and that university-designed monthly examinations were valid testing instruments, but there was an apparent incongruity between the goals of the curriculum and the American Board of Surgery In-Training Examination.

Necrotizing fasciitis of the chest wall.

Necrotizing fasciitis is a highly morbid soft tissue infection that rarely involves the upper torso. An extremely unusual case of necrotizing fasciitis of the chest wall is reported, including the method by which an open thoracic cage was managed. This represents the second reported case of a patient surviving necrotizing fasciitis of the chest wall requiring rib resection and chest wall reconstruction.

Social supports as a determinant of community-based care utilization among rehabilitation patients.

OBJECTIVE: We determine the extent to which noninstitutionalized long-term care patients receive assistance from family members and friends, and evaluate the effect of this assistance on use of outpatient rehabilitative and personal care services. DATA SOURCES AND STUDY SETTING: Over 12 months, primary data were collected from 289 patients in noninstitutional settings after inpatient rehabilitation at three Boston-area rehabilitation hospitals. Data on patients' acute and rehabilitative stays were obtained from medical record reviews. Patients provided primary data on sociodemographics, living arrangements, social supports, functional status, health behaviors, life events, and use of outpatient services during the study period. The latter was verified and service charge data obtained from the care providers. STUDY DESIGN: The study was longitudinal and observational. Patient-provided information was obtained at one, six, and twelve months postdischarge. ANALYTIC METHODS: Multivariate Tobit regression was used to evaluate the effect of social supports on patients' use of rehabilitative and personal care services, controlling for sociodemographics and functional status. Service use was measured as charges incurred during the 12-month study period. PRINCIPAL FINDINGS: Results confirm the primary role of family and friends in providing daily personal care and identify the availability of that support as a key determinant of expenditures on community-based personal care services. Social supports do not predict outpatient rehabilitative service use. CONCLUSIONS: Differing eligibility criteria seem appropriate for outpatient rehabilitative and personal care services. The current emphasis on functional status in determining rehabilitative service eligibility appears appropriate; but we find that considering patients' social supports would be both meaningful and appropriate in determining personal care service eligibility. This approach would avert the expense of making personal care services universally available, while facilitating assistance for patients whose functional and social status put them at increased risk of institutional placement.

Do patient assessments of primary care differ by patient ethnicity?

OBJECTIVE: To determine if patient assessments (reports and ratings) of primary care differ by patient ethnicity. DATA SOURCES/STUDY DESIGN: A self-administered patient survey of 6,092 Massachusetts employees measured seven defining characteristics of primary care: (1) access (financial, organizational); (2) continuity (longitudinal, visit based); (3) comprehensiveness (knowledge of patient, preventive counseling); (4) integration; (5) clinical interaction (communication, thoroughness of physical examinations); (6) interpersonal treatment; and (7) trust. The study employed a cross-sectional observational design. PRINCIPAL FINDINGS: Asians had the lowest primary care performance assessments of any ethnic group after adjustment for socioeconomic and other factors. For example, compared to whites, Asians had lower scores for communication (69 vs. 79, p = .001) and comprehensive knowledge of patient (56 vs. 48, p = .002), African Americans and Latinos had less access to care, and African Americans had less longitudinal continuity than whites. CONCLUSIONS: We do not know what accounts for the observed differences in patient assessments of primary care. The fact that patient reports as well as the more subjective ratings of care differed by ethnicity suggests that quality differences might exist that need to be addressed.

Physiologic effects of pneumoperitoneum.

Laparoscopy requires the establishment of pneumoperitoneum in order to provide adequate surgical exposure and maintain operative freedom. Insufflation of carbon dioxide into the peritoneal cavity, however, can affect several homeostatic systems, leading to alterations in acid-base balance, blood gases, and cardiovascular and pulmonary physiology. Although these changes may be well tolerated by healthy individuals, they may increase physiologic stress in patients with pre-existing conditions, placing them at increased risk for perioperative complications. An understanding of the physiologic changes caused by carboperitoneum is therefore essential for identification of high-risk patients and formulation of appropriate treatment plans, which may include preoperative cardiorespiratory optimization and perioperative monitoring. Under optimal conditions, debilitated patients should be able to tolerate pneumoperitoneum safely and, thereafter, reap the benefits associated with minimally invasive surgery.

Gender differences in medical treatment: the case of physician-prescribed activity restrictions.

A growing scientific literature highlights concern about the influence of social bias in medical care. Differential treatment of male and female patients has been among the documented concerns. Yet, little is known about the extent to which differential treatment of male and female patients reflects the influence of social bias or of more acceptable factors, such as different patient preferences or different anticipated outcomes of care. This paper attempts to ascertain the underlying basis for an observed differential in physicians' tendency to advice activity restrictions for male and female patients. We explore the extent to which the gender-based treatment differential is attributable to: (1) patients' health profile, (2) patients' role responsibilities, (3) patients' illness behaviors, and (4) physician characteristics. These four categories of variables correspond to four prominent social science hypotheses concerning gender differences in health and health care utilization (i.e, biological basis hypothesis, fixed role hypothesis, socialization hypothesis, physician bias hypothesis). Data are drawn from the Medical Outcomes Study (MOS), a longitudinal observational study of 1546 patients of 349 physicians practicing in three U.S. cities. Multivariate logistic regression is used to evaluate the likelihood of physician-prescribed activity restrictions for male and female patients, and to explore the absolute and relative influence of patient and physician factors on the observed treatment differential. Results reveal that the odds of prescribed activity restrictions are 3.6 times higher for female patients than for males with equivalent characteristics. The observed differential is not explained by differences in male and female patients' health or role responsibilities. Gender differences in illness behavior and physician gender biases both appear to contribute to the observed differential. Female patients exhibit more illness behavior than males, and these behaviors increase physicians' tendency to prescribe activity restrictions. After accounting for illness behavior differences and all other factors, the odds of prescribed activity restrictions among female patients of male physicians is four times that of equivalent male patients of those physicians. Medical practice, education, and research must strive to identify and remove the likely unconscious role of social bias in medical decision making.

A topography of psychiatric disorders among correction officers.

This study assessed the nature, scope, and work-related impact of psychiatric disorders among correction officers. It also examined the effect of psychiatric diagnoses on occupational functioning. Medical charts of 1029 correction officers with complaints of psychological distress were reviewed for DSM-III-R diagnoses and duration of disability. Subjects evinced a wide range of psychiatric conditions, accounting for a substantial loss of full-duty workdays. The most frequently observed diagnoses were V Codes, mood and adjustment disorders. The most disabling conditions in terms of duration of disability were mood, anxiety, and personality disorders. V Codes accounted for the highest cumulative duration of disability among all officers. Results suggest that psychiatric disability among correction officers is most often a function of V-Code conditions, as opposed to major Axis I or II psychopathology.

Spontaneous splenic rupture following infectious mononucleosis.

Four cases of spontaneous splenic rupture after infectious mononucleosis (IM) have been treated at this institution since 1978. The condition is rare, occurring in 0.1-0.5 per cent of patients with proven infectious mononucleosis. Splenectomy is considered the treatment of choice for these patients. However, because recent trends in the management of traumatic splenic rupture are moving towards nonoperative treatment with selected patients, a similar approach has been considered for the patient with spontaneous splenic rupture following IM. The major reason for avoiding splenectomy is the increased incidence of sepsis in splenectomized patients. Yet, splenic rupture is accompanied by hemorrhage and the risks associated with blood transfusion for ongoing hemorrhage are of similar magnitude as those of sepsis following splenectomy. In addition, the grossly abnormal spleens seen at operation tend to include large, contained hematomas that may also be prone to rupture. Therefore, operative management still appears to be the preferred treatment for spontaneous splenic rupture following IM. Splenectomy is curative, safe, and obviates the need for transfusion, extended hospitalization, and activity restriction.

Cholecystectomy following the introduction of laparoscopy: more, but for the same indication.

To assess whether indications for cholecystectomy might have changed after the introduction of laparoscopic cholecystectomy (LC), the data from patients undergoing cholecystectomy at the University of South Alabama Medical Center during 1988 (before LC) and 1993 (after the introduction of LC) were retrospectively analyzed and compared. In 1993, the number of patients undergoing cholecystectomy for gallstone-related disease was 18 per cent higher than in 1988 (87 vs 103, 1.4 per cent of all noncardiac operations vs 2.7 per cent, Chi square; P = 0.003). There was no difference in the mean Preoperative Severity Index, a quantitative evaluation of symptom complex, preoperative laboratory evaluation, and radiological findings. Besides obesity, there were also no differences between the groups in associated comorbidities that might affect the decision to proceed with operation. Furthermore, pathologic findings, including the distribution of patients with gallstone pancreatitis, symptomatic cholelithiasis, chronic cholecystitis, and acute cholecystitis, were similar in both groups. The indications for cholecystectomy did not broaden after the introduction of LC, but rather, more patients with similar indications are undergoing cholecystectomy now, as compared with the pre-laparoscopic era.