What is the effect of reducing the air change rate on the ventilation effectiveness in ultra-clean operating rooms?

BACKGROUND: The operating room (OR) department is one of the most energy-intensive departments of a hospital. The majority of ORs in the Netherlands have an air-handling installation with an ultra-clean ventilation system. However, not all surgeries require an ultra-clean OR. AIM: To determine the effect of reducing the air change rate on the ventilation effectiveness in ultra-clean ORs. METHODS: Lower air volume ventilation effectiveness (VELv) of conventional ventilation (CV), controlled dilution ventilation (cDV), temperature-controlled airflow (TcAF) and unidirectional airflow (UDAF) systems were evaluated within a 4 × 4 m measuring grid of 1 × 1 m. The VELv was defined as the recovery degree (RD), cleanliness recovery rate (CRR) and air change effectiveness (ACE). FINDINGS: The CV, cDVLv and TcAFLv ventilation systems showed a comparable mixing character in all areas (A, B and AB) when reducing the air change rate to 20/h. Ventilation effectiveness decreased when the air change rate was reduced, with the exception of the ACE. At all points for the UDAF-2Lv and at the centre point (C3) of the TcAFLv, higher RD10Lv and CRRLv were measured when compared with the other examined ventilation systems. CONCLUSIONS: The ventilation effectiveness decreased when an ultra-clean OR with an ultra-clean ventilation air-supply system was switched to an air change rate of 20/h. Reducing the air change rate in the OR from an ultra-clean OR to a generic OR will reduce the recovery degree (RD10) by a factor of 10-100 and the local air change rate (CRR) by between 42% and 81%.

Operating room ventilation systems: recovery degree, cleanliness recovery rate and air change effectiveness in an ultra-clean area.

BACKGROUND: Entrainment test methods are described in most European standards and guidelines to determine the protected area for ultra-clean ventilation (UCV) systems. New UCV systems, such as temperature-controlled airflow (TcAF) and controlled dilution ventilation (cDV) systems, claim the whole operating room (OR) to be ultra-clean. However, current test standards were not developed to assess ventilation effectiveness outside the standard protected area. AIM: To assess and compare the ventilation effectiveness of four types of OR ventilation systems in the ultra-clean area using a uniform test grid. METHODS: Ventilation effectiveness of four ventilation systems was evaluated for three different ultra-clean (protected) areas: the standard protected area (A); the area outside the standard protected area (B); and a large protected area (AB). Ventilation effectiveness was assessed using recovery degree (RD), cleanliness recovery rate (CRR) and air change effectiveness (ACE). FINDINGS: RD, CRR and ACE were significantly higher for the unidirectional air flow (UDAF) system compared with the other systems in area A. In area B, the UDAF and cDV systems were comparable for RD and CRR, and the UDAF and conventional ventilation (CV) systems were comparable for ACE. In area AB, the UDAF and cDV systems were comparable for CRR and ACE, but significant differences were found in RD. CONCLUSION: In area A, the ventilation effectiveness of the UDAF system outperformed other ventilation systems. In area B, the cDV system was best, followed by the UDAF, TcAF and CV systems. In area AB, the UDAF system was best, followed by the cDV, TcAF and CV systems.

Cartilage and subchondral bone distributions of the distal radius: a 3-dimensional analysis using cadavers.

OBJECTIVE: To quantify the spatial distributions of cartilage and subchondral bone thickness of the distal radius. DESIGN: Using 17 cadaveric wrists, three types of 3-dimensional models were created: a cartilage-bone model, obtained by laser scanning; a bone model, rescanned after dissolving the cartilage; and a subchondral bone model, obtained using computed tomography. By superimposing the bone model onto the cartilage-bone and the subchondral bone models, the cartilage and subchondral bone thickness were determined. Measurements along with the spatial distribution were made at fixed anatomic points including the scaphoid and lunate fossa, sigmoid notch and interfossal ridge, and compared at each of these four regions. RESULTS: Cartilage thickness of the interfossal ridge (0.89 ± 0.23 mm) had a larger average thickness compared to that of the scaphoid fossa (0.70 ± 0.18 mm; p = 0.004), lunate fossa (0.75 ± 0.17 mm; p = 0.044) and sigmoid notch (0.64 ± 0.13 mm; p < 0.001). Subchondral bone was found to be thickest at the scaphoid (2.18 ± 0.72 mm) and lunate fossae (1.94 ± 0.93 mm), which were both thicker than that of sigmoid notch (1.63 ± 1.06 mm: vs scaphoid fossa, p = 0.020) or interfossal ridge (1.54 ± 0.84 mm: vs scaphoid fossa, p = 0.004; vs lunate fossa, p = 0.048). In the volar-ulnar sub-regions of the scaphoid and lunate fossa, the subchondral bone thickened. CONCLUSIONS: Our data can be applied when treating distal radius fractures. Cartilage thickness was less than 1 mm across the articular surface, which may give an insight into threshold for an acceptable range of step-offs. The combined findings of subchondral bone appreciate the importance of the volar-ulnar corner of the distal radius in the volar locking plate fixation.

[Response to treatment and survival of adults with acute leukemia classified with immunophenotyping and cytochemistry]. / Respuesta al tratamiento y supervivencia de adultos con leucemia aguda clasificados mediante inmunofenotipo y citoquímica.

We studied the response to treatment and survival of 30 adults with acute lymphocytic leukemia (ALL) and 19 with acute non lymphoid leukemia (ANLL) classified on basis of immunophenotype (monoclonal antibodies) and cytochemistry. For the ALL cases 70% corresponded to common ALL (CALLA positive), 23% to B lymphocytes and 7% to T cells. We had 68% of the ANLL patients classified as myeloid, 21% as hybrid (positive both myeloid and lymphoid markers) and 11% as undifferentiated. We analyzed demographic data (gender and age), basic laboratory values (hemoglobin, leucocytes, platelets and cytomorphology in peripheral blood and bone marrow) using the French-American-British classification, and found no statistically significant differences between ALL and ANLL. Three of four patients (75%) with hybrid ANLL achieved complete remission (CR), while 46% of cases with myeloid ANLL and none of the subjects with undifferentiated ANLL reached CR; these differences were not statistically significant. Patients with common ALL had a median survival (SV) of 499 days, for B cell ALL it was of 212 days, and for T cell ALL of 285 days. Our data suggest that: a) expression of lymphoid markers in patients with ANLL is probably associated with a higher CR ratio, and b) SV in adults with common ALL seems to be longer than in those with B and T cell ALL.

[Cytogenetic findings in chronic myelocytic leukemia and their prognostic correlation in patients of the National Institute of Cancer of Mexico]. / Hallazgos citogenéticos en leucemia mielocítica crónica y su correlación pronóstica en pacientes del Instituto Nacional de Cancerología de México.

This study describes the cytogenetic alterations in patients with chronic myelogenous leukemia (CML) seen at the Instituto Nacional de Cancerologia (INCAN), Mexico City, whether they have been treated previously or not. It correlates these findings with the prognosis. We studied 31 patients seen during June 1987 and June 1990. Philadelphia (Ph+) chromosome was present in 61% of all specimens. In 10 cases it was the only anomaly, resulting in a survival greater than 40 months. Aneuploidies were seen in 50% of patients with previous treatment and in 31.5% of those without treatment. Patients with numerous abnormalities and double Ph+ (with or without Ph+ chromosome) had a mean survival of 32 months. The worst prognosis was seen in the a cases with no growth, with a mean survival of 19 months. This study suggests that the prognosis of patients with CML correlates with the cytogenetic anomalies whether patients have been treated previously or not. It also seems that the group of patients whose cytogenetic study does not grow or cannot be evaluated upon direct exam have a worse prognosis which may be secondary to intrinsic defects of the neoplastic cells that do not grow in vitro, resulting in a more aggressive disease in vivo.

Endoscopic therapy in patients with pancreas divisum and acute pancreatitis: a prospective, randomized, controlled clinical trial.

Endoscopic endoprosthesis (stent) placement across the minor papilla has been shown to be beneficial in reducing abdominal pain and episodes of pancreatitis in a small group of patients with pancreas divisum and acute recurrent pancreatitis. In a randomized, controlled clinical trial, 19 patients with pancreas divisum and at least 2 documented episodes of pancreatitis were randomized to either dorsal duct stent placement (10 patients--5 women and 5 men) or controls (9 patients--6 women and 3 men). All other causes of pancreatitis were excluded. Patients were followed at 4-month intervals for evaluation and/or stent exchange during a 1-year period. The following criteria were evaluated during follow-up: number of hospitalizations or emergency room visits, the number of documented episodes of pancreatitis, and gradation of the patient's overall general feeling based on a visual analog scale. Mean follow-up times in the stent and control groups were 28.6 and 31.5 months, respectively (p greater than 0.05, NS). No patients in the stent group required hospitalization or emergency room visits for abdominal pain only during and following the treatment period. However, in the control group there were five hospitalizations and two emergency room visits for abdominal pain during a similar period (p less than 0.05). Pancreatitis was documented with an elevated amylase twice the normal range, one time in the stent group and seven times in the control group (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Supplemental calcium suppresses colonic mucosal ornithine decarboxylase activity in elderly patients with adenomatous polyps.

Epidemiological and animal studies suggest a role for calcium in the chemoprevention of colorectal neoplasia. This study was designed to investigate whether supplemental oral calcium has a suppressant effect on colonic mucosal ornithine decarboxylase (ODC) and tyrosine kinase activities in patients with adenomatous polyps or a history of adenomatous polyps and whether this is affected by age. ODC and tyrosine kinase activities were measured in rectal mucosal biopsies of 19 male patients (age, years 46-85 years; mean, 66 years) with adenomatous polyps or a history of adenomatous polyps before and after 1 week of calcium supplementation p.o. (CaCO3; 2500 mg/day) and 2 weeks after cessation of calcium treatment. The basal rectal mucosal ODC activity of patients greater than or equal to 64 years old was nearly 4-fold higher than that of patients less than 64 years old (P less than 0.005). In patients greater than or equal to 64 years old, there was a significant decrease in rectal mucosal ODC activity following 1 week of calcium p.o. compared to those age less than 64 years (P less than 0.05). Overall tyrosine kinase activity did not differ significantly in either patient group before or after calcium supplementation p.o. However, the concentration of phosphotyrosine membrane proteins with molecular weights between 40,000 and 60,000 and between 80,000 and 100,000 were suppressed in patients age greater than or equal to 64 years after 1 week of calcium treatment p.o. These patients also had a corresponding decrease in their rectal mucosal ODC activity. Alternatively, patients whose ODC was not affected by calcium showed no apparent change in the relative concentration of rectal mucosal phosphotyrosine membrane proteins. Our data indicate that there is an age-related increase in basal rectal mucosal ODC activity in patients with adenomatous polyps which can be suppressed with calcium supplementation p.o., suggesting a role for dietary calcium in the chemoprevention of colorectal neoplasia.