Cost-Effective Filtrating Suction to Evacuate Surgical Smoke in Laparoscopic and Robotic Surgery During the COVID-19 Pandemic.

The wide and fast spread of COVID-19 around the world has led to a dramatic increase in the need for protection products both for carers and for populations. Surgical team protection includes a systematic screening of patients, wearing protection devices by all the operating staff, and adequate management of aerosols. The risk of aerosol dispersal is particularly high during laparoscopic and robotic surgeries due to the interaction between circulating CO2 and surgical smoke that may contain small viral particles. To decrease the risk of virus transmission, many recommendations have been implemented including the use of integrated insufflation devices comprising smoke evacuation and filtration mode. Such devices are lacking in many centers around the world and to overcome this urgent unmet need, we designed a cost-effective filtrating suction as a more readily available alternative.

Novel, digital, chest drainage system in cardiac surgery.

BACKGROUND: A new, self-contained, digital, continuous pump-driven chest drainage system is compared in a randomized control trial to a traditional wall-suction system in cardiac surgery. METHODS: One hundred and twenty adult elective cardiac patients undergoing coronary artery bypass graft and/or valve surgery were randomized to the study or control group. Both groups had similar pre/intra-operative demographics: age 67.8 vs 67.0 years, Euroscore 2.3 vs 2.2, and body surface area 1.92 vs 1.91 m2 . Additionally, a satisfaction assessment score (0-10) was performed by 52 staff members. RESULTS: Given homogenous intra-operative variables, total chest-tube drainage was comparable among groups (566 vs 640 mL; ns), but the study group showed more efficient fluid collection during the early postoperative phase due to continuous suction (P = .01). Blood, cell saver transfusions and postoperative hemoglobin values were similar in both groups. The study group experienced drain removal after 29.8 vs 38.4 hours in the control group (ns). Seven crossovers from the Study to the Control group were registered but no patient had drain-related complications. The Personnel Satisfaction Assessment scored above 5 for all questions asked. CONCLUSIONS: The new, digital, chest drainage system showed better early drainage of the chest cavity and was as reliable as conventional systems. Quicker drain removal might impact on intensive care unit (ICU) stay and reduce costs. Additional advantages are portable size, battery operation, patient mobility, noiseless function, digital indications and alarms. The satisfaction assessment of the new system by the staff revealed a higher score when compared to the traditional wall suction chest drainage system.

A Comparative Study of Percutaneous Aspiration with Sclerotherapy and Laparoscopic Marsupialization for Symptomatic Simple Renal Cysts.

Background: Percutaneous aspiration with sclerotherapy (PAS) and laparoscopic marsupialization (LM) are minimally invasive treatment modalities for renal cysts. We aimed to compare the efficacy and cost/effectiveness of LM and PAS for the treatment of simple symptomatic renal cysts. Methods: Data were prospectively collected from three health care institutions in which 80 patients with symptomatic simple renal cysts underwent a single session of PAS with 95% ethanol (PAS group, n = 40) or underwent LM under general anesthesia (LM group, n = 40) between March 2012 and May 2016. We compared the patient profile, duration of procedure, duration of hospital stay, radiological and symptomatic success rates, treatment costs, and incidence of complications between the two groups. Results: At the 6-month follow-up, the radiological success rate in the LM group was significantly greater than that in the PAS group (97.5% versus 60%; P < .001). The symptomatic success rate was comparable in the two groups (95% versus 90%; P = .675). The treatment failure rate did not significantly differ between the two groups (5.0% versus 17.5%, P = .154). The mean total cost in the PAS and LM groups was 1256 USD and 2343 USD, respectively (P = .001). No significant between-group difference was noted regarding the overall complication rate (P = .615). Conclusions: Both LM and PAS are effective and safe procedures for the treatment of symptomatic simple renal cysts. A single session of PAS seems to be a cost-effective method for the management of symptomatic simple renal cysts.

Which way is best for stone fragments and dust extraction during percutaneous nephrolithotomy.

Percutaneous nephrolithotomy (PCNL) is a commonly used type of minimally invasive treatment in kidney stone surgeries. Surgical success is assessed according to residual stone amount after surgery. The purpose of this study is to compare the two methods' success and practicality that are applied after the fracture of the stone in the patients who applied PCNL and which enable the removal of the residual stones. Among 102 patients who underwent a single-session of PCNL at our department between June 2015 and November 2016 were evaluated. Previously identified irrigation method and our aspiration method which described used in post-operative patients divided into two groups of residual fragments was assessed by computed tomography. The results were evaluated in statistical analyses. Significant p was accepted as p < 0.05. The age and gender distribution of patients in the irrigation and aspiration groups did not differ significantly (p > 0.05). In irrigation and aspiration groups, stone size did not differ significantly (p > 0.05). The amount of residue stones and dust remaining in the irrigation group was significantly higher (p < 0.05) than the aspiration group. Although many methods have been tried before, we think that the aspiration method we have described is a cheaper, more effective and feasible option.

Fluoroscopy- vs ultrasound-guided aspiration techniques in the management of periprosthetic joint infection: which is the best?

BACKGROUND: Fluid samples obtained from an affected joint still play a central role in the diagnosis of periprosthetic joint infection (PJI). It is the only preoperative test able to discover the causative microbiological agent. In the hip, fluid aspiration can be performed through fluoroscopy, ultrasound, or, less commonly, computed tomography. However, there is still a lack of consensus on which method is preferable in terms of efficacy and costbenefit. PURPOSES: We, therefore, asked whether (1) the benefits in terms of sensitivity and specificity and (2) the costs were comparable between fluoroscopy- and ultrasound-guided joint aspirations in a suspicious of hip PJI. METHODS: Between 2013 and 2016, 52 hip aspirations were performed on 49 patients with clinical, radiological, or serological suspicion of PJI, waiting for a revision surgery. The patients were divided in two groups: fluoroscopy- (n = 26) vs ultrasound-guided hip aspiration group (n = 26). These groups were also divided in control and infected patients. The criteria of MusculoSkeletal Infection Society (MSIS) were used, as gold standard, to define PJI. RESULTS: (1) Ultrasound-guided aspiration revealed valid sensitivity (89% vs 60%) and specificity (94% vs 81%) in comparison with fluoroscopic-guided aspiration. (2) The cost analysis was also in favor of ultrasound-guided aspiration (125.30€) than fluoroscopic-guided aspiration (343.58€). CONCLUSIONS: We concluded that ultrasound-guided hip aspiration could represent a valid, safe, and less expensive diagnostic alternative to fluoroscopic-guided aspiration in hip PJI.

Controlled Suction with Venous Catheter Irrigation in Neurosurgery: A Cost Effective Technique.

BACKGROUND: Keeping the operating field clean and visible is an important technique in neurosurgery. Continuous irrigation-suction (IS) of the surgical field is currently often done using devices available that are expensive and demand technical proficiency. We report a simple method of continuous IS using a widely available central venous catheter and a controlled suction cannula. METHODS: We used a controlled suction cannula attached to a central suction system. A single lumen central venous catheter is passed through the keyhole of a controlled suction cannula, which is connected to a continuous irrigation system. RESULTS: The operative field was clean throughout the procedure, obviating the need for an assisting surgeon to irrigate into the deep operating field and, hence, reducing the duration of surgery. CONCLUSIONS: The proposed IS system could be surgeon friendly, easily manageable, yet cost-effective and efficient.

Factors influencing drainage setting and cost for cutaneous abscesses among pediatric patients.

OBJECTIVE: To evaluate the clinical and microbiological factors associated with skin and soft tissue infections drained in the emergency department (ED) vs operative drainage (OD) in a tertiary care children's hospital. METHODS: This was a cross-sectional study among children aged 2 months to 17 years who required incision and drainage (I&D). Demographic information, signs and symptoms, abscess size and location, and wound culture/susceptibility were recorded. Patient-specific charges were collected from the billing database. Multivariate regression analysis was used to determine factors determining setting for I&D and the effect of abscess drainage location on cost. RESULTS: Of 335 abscesses, 241 (71.9%) were drained in the ED. OD for abscesses was favored in children with prior history of abscess (odds ratio [OR], 3.18; 95% confidence interval [CI], 1.36-7.44; P = .01) and labial location (OR, 37.81; 95% CI, 8.12-176.03; P < .001). For every 1-cm increase in size, there was approximately a 26% increase in the odds of having OD (OR, 1.26; 95% CI, 1.11-1.44, P < .001). Methicillin-resistant Staphylococcus aureus was identified in 72% of the 300 abscesses cultured and 12.3% were clindamycin resistant. OD was more expensive than I&D in the ED. Per abscess that underwent I&D, OD is $3804.29 more expensive than I&D in the ED while controlling for length of stay. DISCUSSION: Clinical factors associated with OD rather than I&D in the ED included history of abscess, increased abscess length, and labial location. Microbiological factors did not differ based on I&D setting. For smaller, nonlabial abscesses, ED drainage may result in significant cost savings.

The increased total cost associated with post-operative drains in total hip and knee arthroplasty.

In a consecutive series of 536 unilateral primary total hip arthroplasties (THAs) and 598 unilateral primary total knee arthroplasties (TKAs), the use of a post-operative drain was associated with $538 additional cost per THA, and $455 for TKA. The use of a drain increased hospital length of stay (LOS) for THA, but not for TKA. In both groups, the use of a drain increased estimated blood loss (EBL) and increased the amount of allogeneic blood transfused. Over the 10-week period, drain use was associated with a total cost of $432,972 for our institution. Data from this study would favor a selective approach to the use of drains in primary joint arthroplasties.

Comparison of gravity collection versus suction collection for transfusion purposes in dogs.

Blood donation is an essential step in transfusion medicine that must take into account the donor's welfare, collection effectiveness, and blood product quality. This prospective study enrolled 13 canine blood donors, each subjected to both gravity and suction collection methods, in a randomized order. Clinical parameters, including heart rate (HR), respiratory rate (RR), systolic blood pressure (SBP), and rectal temperature (RT), were evaluated at four time points, including when the donor was on the floor and on the collection table, and before and after blood donation. The number of times the donor and needle required repositioning, the duration of the donation, the noise created by the apparatus, and the presence of a hematoma were evaluated. The weight, index of hemolysis, and hematocrit of each unit of blood were recorded. There was no significant difference between collection methods for either the clinical parameters at each time point or the prevalence of hematoma formation, the frequency of needle repositioning, the hemolysis index, or hematocrit. Collection by suction was noisier (P < 0.0001), faster (P = 0.004), and associated with significantly less donor repositioning (P = 0.007). Suction appears to be a safe and cost-effective method that should be considered to optimize blood donation.

Impact of the learning curve in the use of a novel electronic chest drainage system after pulmonary lobectomy: a case-matched analysis on the duration of chest tube usage.

The objective of this investigation was to verify the impact of the learning curve involved after the introduction of a novel electronic chest drainage device on the duration of chest tube usage following pulmonary lobectomy. Propensity score case-matched analysis was used to compare the first consecutive 51 lobectomy patients managed with an electronic chest drainage (E) device with 51 controls managed with a traditional device (T). There was no difference in the characteristics of the two matched groups. Compared with patients managed with a traditional device, those with the electronic one had 1.9-day shorter duration of chest tube drainage (2.5 vs. 4.4 days; P<0.0001) and a 1.5-day shorter hospital stay (4.5 vs. 6 days; P=0.0003). Consequently, they had an average reduction in hospital costs of €751 (€1802 vs. €2553; P=0.0002). Compared with those in group T, patients in group E had a consistently shorter duration of chest tube use in relation to the very first patients treated. The learning curve sloped down for the first 40 patients before reaching a plateau, when the maximum benefit of using the electronic device was evident. Compared with traditional devices, the use of a novel electronic chest drainage system was beneficial from its initial application. The inherent learning curve was short and did not affect the efficiency of the system.

Is continuous subglottic suctioning cost-effective for the prevention of ventilator-associated pneumonia?

OBJECTIVE: To establish whether continuous subglottic suctioning (CSS) could be cost-effective. DESIGN: Cost-benefit analysis, based on a hypothetical replacement of conventional ventilation (CV) with CSS. SETTING: A surgical intensive care unit (SICU) of a tertiary care university hospital in France. PATIENTS: All consecutive patients receiving ventilation in the SICU in 2006. METHODS: Efficacy data for CSS were obtained from the literature and applied to the SICU of our hospital. Costs for CV and CSS were provided by the hospital pharmacy; costs for ventilator-associated pneumonia (VAP) were obtained from the literature. The cost per averted VAP episode was calculated, and a sensitivity analysis was performed on VAP incidence and on the number of tubes required for each patient. RESULTS: At our SICU in 2006, 416 patients received mechanical ventilation for 3,487 ventilation-days, and 32 VAP episodes were observed (7.9 episodes per 100 ventilated patients; incidence density, 9.2 episodes per 10,000 ventilation-days). Based on the hypothesis of a 29% reduction in the risk of VAP with CSS than CV, 9 VAP episodes could have been averted. The additional cost of CSS for 2006 was estimated to be €10,585.34. The cost per averted VAP episode was €1,176.15. Assuming a VAP cost of €4,387, a total of 3 averted VAP episodes would neutralize the additional cost. For a low VAP incidence of 6.6%, the cost per averted VAP would be €1,323. If each patient required 2 tubes during ventilation, the cost would be €1,383.69 per averted VAP episode. CONCLUSION: Replacement of CV with CSS was cost-effective even when assuming the most pessimistic scenario of VAP incidence and costs.

An open-labelled randomized controlled trial comparing costs and clinical outcomes of open endotracheal suctioning with closed endotracheal suctioning in mechanically ventilated medical intensive care patients.

PURPOSE: Closed endotracheal suctioning (CES) may impact ventilator-associated pneumonia (VAP) risk by reducing environmental contamination. In developing countries where resource limitations constrain the provision of optimal bed space for critically ill patients, CES assumes greater importance. MATERIALS AND METHODS: In this prospective, open-labeled, randomized controlled trial spanning 10 months, we compared CES with open endotracheal suctioning (OES) in mechanically ventilated patients admitted to the medical intensive care unit (ICU) of a university-affiliated teaching hospital. Patients were followed up from ICU admission to death or discharge from hospital. Primary outcome was incidence of VAP. Secondary outcomes included mortality, cost, and length of stay. RESULTS: Two hundred patients were recruited, 100 in each arm. The incidence of VAP was 23.5%. Closed endotracheal suctioning was associated with a trend to a reduced incidence of VAP (odds ratio, 1.86; 95% confidence interval, 0.91-3.83; P = .067). A significant benefit was, however, observed with CES for late-onset VAP (P = .03). Mortality and duration of ICU and hospital stay were similar in the 2 groups. The cost of suction catheters and gloves was significantly higher with CES (Rs 272 [US $5.81] vs Rs 138 [US $2.94], P < .0001). Nine patients need to be treated with CES to prevent 1 VAP (95% confidence interval, -0.7 to 22). CONCLUSIONS: In the ICU setting in a developing country, CES may be advantageous in reducing the incidence of VAP, particularly late-onset VAP. These results mandate further studies in this setting before specific guidelines regarding the routine use of CES are proposed.

Randomized controlled trial of pelvic calcium alginate following rectal cancer surgery.

BACKGROUND: The aim of this randomized controlled trial was to assess the possible benefit of using a new haemostatic agent (Hémoionic) in the pelvic cavity in sphincter-saving surgery for rectal cancer. METHODS: Eighty-five patients undergoing elective sphincter-saving rectal resection for cancer were randomized into Hémoionic (41 patients) and control (44) groups. In both groups, a pelvic suction drain was left in place for as long as the daily output exceeded 20 ml. The primary endpoint was volume of fluid collected by the suction drain; secondary endpoints were duration of drainage, and postoperative mortality and morbidity rates. RESULTS: The mean total drainage volume was significantly lower in the Hémoionic group (453 ml versus 758 ml in control group; P = 0.031). There was no significant difference between groups in duration of drainage and morbidity. The mortality rate was four of 41 in the Hémoioni group and one of 44 in the control group (P = 0.192). CONCLUSION: Hémoionic may reduce the drainage volume after sphincter-saving surgery for rectal cancer, but offers no clinical advantage. REGISTRATION NUMBER: ISRCTN79721331 (http://www.isrctn.org).

The initial maternal cost of providing 100 mL of human milk for very low birth weight infants in the neonatal intensive care unit.

OBJECTIVES: Human milk (HM) feeding is associated with lower incidence and severity of costly prematurity-specific morbidities compared to formula feeding in very low birth weight (VLBW; <1,500 g) infants. However, the costs of providing HM are not routinely reimbursed by payers and can be a significant barrier for mothers. This study determined the initial maternal cost of providing 100 mL of HM for VLBW infants during the early neonatal intensive care unit (NICU) stay. METHODS: This secondary analysis examined data from 111 mothers who provided HM for their VLBW infants during the early NICU stay. These data were collected during a multisite, randomized clinical trial where milk output and time spent pumping were recorded for every pumping session (n = 13,273). The cost analysis examined the cost of the breast pump rental, pump kit, and maternal opportunity cost (an estimate of the cost of maternal time). RESULTS: Mean daily milk output and time spent pumping were 558.2 mL (SD = 320.7; range = 0-2,024) and 98.7 minutes (SD = 38.6; range = 0-295), respectively. The mean cost of providing 100 mL of HM varied from $2.60 to $6.18 when maternal opportunity cost was included and from $0.95 to $1.55 when it was excluded. The cost per 100 mL of HM declined with every additional day of pumping and was most sensitive to the costs of the breast pump rental and pump kit. CONCLUSIONS: These findings indicate that HM is reasonably inexpensive to provide and that the maternal cost of providing milk is mitigated by increasing milk output over the early NICU stay.

Comparação entre os sistemas aberto e fechado de aspiração: revisão sistemática / Comparison between open and closed suction systems: a systematic review

OBJETIVOS: Este estudo foi realizado para tentar esclarecer qual sistema de aspiração é mais eficiente. O objetivo foi comparar os sistemas fechado e aberto de aspiração através de revisão sistemática. MÉTODOS: A busca de artigos científicos foi realizada nas bases de dados MedLine, LILACS e Cochrane abrangendo o período entre 1997 e agosto de 2007 utilizando as palavras-chave: endotracheal suction e closed suction. Foram incluídos os estudos que compararam o sistema aberto e fechado de aspiração, realizados em adultos humanos e que eram ensaios aleatórios e controlados. RESULTADOS: Dos 78 artigos encontrados apenas 15 preencheram os critérios e foram detalhados na revisão. Dentre estes, nove artigos comparavam a incidência de pneumonia associada à ventilação mecânica entre os dois sistemas, seis comparavam a saturação de oxigênio, quatro comparavam pressão arterial e freqüência cardíaca, três comparavam volumes pulmonares, dois comparavam remoção de secreção e quatro; custos. Não houve diferença em relação às variáveis comparadas: incidência de pneumonia associada à ventilação mecânica, mortalidade, tempo de unidade de terapia intensiva, tempo de ventilação mecânica, PaCO2, PaO2, pressão arterial média, freqüência cardíaca e remoção de secreção no uso do sistema aberto e fechado de aspiração. Porém, houve sempre diminuição de SpO2 e dos volumes pulmonares com o uso do sistema aberto; e custos maiores na maioria dos trabalhos quando utilizado o sistema fechado. CONCLUSÕES: O sistema fechado de aspiração parece aumentar o risco de colonização, mas traz as vantagens de não diminuir os volumes pulmonares e não acarretar queda de saturação especialmente em pacientes com insuficiência respiratória grave e em uso de níveis mais altos de pressão expiratória final positiva.

OBJECTIVES: This study attempted to identify which is the more effective suction system. The objective was to compare open versus closed suction systems according to a systematic review. METHODS: A search of scientific literature was conducted in MedLine, LILACS and Cochrane between 1997 and August 2007 using the key words: endotracheal suction and closed suction. Included were articles that compared the open and closed suction systems used in adult humans and that were randomized and controlled trials. RESULTS: From the 78 articles identified, only 15 were accepted and described in this review. Nine compared incidence of ventilator-associated pneumonia, six compared oxygen saturation, four compared blood pressure and heart rate, three compared pulmonary volumes, two compared secretion removal and four compared costs. No difference was found in these variables compared: incidence of ventilator associated pneumonia, mortality, intensive care unit length of stay, duration of mechanical ventilation, PaCO2, PaO2, mean blood pressure, heart rate and secretion removal. However, there were always SpO2 and pulmonary volume decreases when using the open suction system; and costs were lower in most of the studies that used the closed suction system. CONCLUSIONS: Closed suction system seems to increase the risk of colonization, but has the advantage of not reducing the pulmonary volumes and not entailing a drop of saturation, especially in patients with severe respiratory failure and in the use of higher levels of positive end expiratory pressure.

[Therapeutic effects of aspiration with a directional soft tube and conservative treatment on mild hemorrhage in the basal ganglion].

OBJECTIVE: To compare the therapeutic effects of aspiration via a directional soft tube and conservative treatment in patients with mild hemorrhage in the basal ganglion. METHODS: Seventy-five patients with mild cerebral hemorrhage (10~30 ml) were randomly divided into two groups for aspiration treatment with minimally invasive directional soft tube placement (minimally invasive group, n=36) and conservative treatment (medication group, n=39). The patients in the two groups had comparable mean GCS scores of 11-15 on admission. The clinical outcomes of the patients were compared between the two groups. RESULTS: In the minimally invasive group, complete removal or absorption of the hematoma occurred within an average of 3.8 days, significantly shortened in comparison with the 24 days in the medication group. The short-term (1 month) follow-up of the patients showed good neurological recovery in 58% of the patients in the minimally invasive group, significantly greater than the rate of 29% in the medication group; 6 months after the treatment, good neurological recovery was achieved in 50% of the patients in the minimally invasive group, but only 16% in the medication. No death occurred in the minimally invasive group, and 2 patients died in the medication group. The cost of hospitalization averaged 5136.3 Yuan in the minimally invasive group and 11843.6 Yuan in the medication group. CONCLUSION: Compared with conservative treatment, the minimally invasive treatment with soft tube placement can significantly shorten the hospital stay, promote neurological function recovery, lower the mortality rate, and reduce the cost of hospitalization.

Salvage for unsuccessful aspiration of primary pneumothorax: thoracoscopic surgery or chest tube drainage?

BACKGROUND: Simple aspiration is recommended as first-line treatment for all primary spontaneous pneumothoraces requiring intervention. However, the optimal salvage treatment remains unclear when simple aspiration is unsuccessful for controlling symptoms. In this study, the safety, efficacy, and estimated costs of video-assisted thoracoscopic surgery (VATS) and chest tube drainage (CTD) were compared. METHODS: Between 2002 and 2007, 164 patients with a first episode of spontaneous pneumothorax were managed by simple aspiration. Among them, 52 patients underwent subsequent VATS (30 patients) or CTD (22 patients) due to unsuccessful aspiration. The demographic data and treatment outcomes of the two groups were collected through retrospective chart review. RESULTS: Postoperative analgesics use did not differ between groups. Complications developed in 2 of the VATS group (6.7%) and 6 of the CTD group (27.3%), with mean hospital stays of 4.8 and 6.1 days, respectively (p = 0.034). Patients in the VATS group had lower rates of overall failure, although the rates of immediate failure were not significantly different. After a mean follow-up of 16 months, recurrent ipsilateral pneumothorax was noted in 1 VATS patient and 5 CTD individuals (p = 0.038). The estimated total costs per patient were $1,273 in the VATS group and $865 in the CTD group. CONCLUSIONS: Although associated with higher costs, VATS rather than CTD is the preferred salvage treatment for unsuccessful aspiration of the first episode of primary spontaneous pneumothorax, because of shorter hospital stay and lower rates of overall failure and recurrence.

Closed tracheal suction systems for prevention of ventilator-associated pneumonia.

We have assessed the evidence that closed tracheal suction systems (TSS) prevent ventilator-associated pneumonia (VAP), using a meta-analysis of randomized controlled trials (RCTs). We searched PubMed and Cochrane databases to identify RCTs that compared closed with open TSS for the management of mechanically ventilated (MV) patients. Nine RCTs were included in the meta-analysis. There was no difference in the incidence of VAP between patients managed with closed and open TSS [odds ratio (OR)=0.96, 95% confidence intervals (CI) 0.72-1.28]. There was no heterogeneity among the eligible trials (I2=0, 95% CI 0-0.65). The compared groups did not differ with respect to mortality (OR=1.04, 95% CI 0.78-1.39) or intensive care unit (ICU) length of stay [two RCTs: 12.3 (sd 1.1) vs 11.5 (1.4) days and 15.6 (13.4) vs 19.9 (16.7) days]. Suctioning with closed systems was associated with longer MV duration (weighted mean differences: 0.65 days, 95% CI 0.28-1.03) and higher colonization of the respiratory tract (OR=2.88, 95% CI 1.50-5.52) than open TSS. The available evidence suggests that closed as opposed to open TSS usage did not provide any benefit on VAP incidence, mortality, or ICU stay of MV patients.