Prediction of massive transfusion in trauma patients in the surgical intensive care units (THAI-SICU study).

PURPOSE: After damage control surgery, trauma patients are transferred to intensive care units to restore the physiology. During this period, massive transfusion might be required for ongoing bleeding and coagulopathy. This research aimed to identify predictors of massive blood transfusion in the surgical intensive care units (SICUs). METHODS: This is an analysis of the THAI-SICU study which was a prospective cohort that was done in the 9-university-based SICUs in Thailand. The study included only patients admitted due to trauma mechanisms. Massive transfusion was defined as received ≥10 units of packed red blood cells on the first day of admission. Patient characteristics and physiologic data were analyzed to identify the potential factors. A multivariable regression was then performed to identify the significant model. RESULTS: Three hundred and seventy patients were enrolled. Sixteen patients (5%) received massive transfusion in the SICUs. The factors that significantly predicted massive transfusion were an initial sequential organ failure assessment (SOFA) ≥9 (risk difference (RD) 0.13, 95% confidence interval (CI): 0.03-0.22, p = 0.01); intra-operative blood loss ≥ 4900 mL (RD 0.33, 95% CI: 0.04-0.62, p = 0.02) and intra-operative blood transfusion ≥ 10 units (RD 0.45, 95% CI: 0.06 to 0.84, p = 0.02). The probability to have massive transfusion was 0.976 in patients who had these 3 factors. CONCLUSION: Massive blood transfusion in the SICUs occurred in 5%. An initial SOFA ≥9, intra-operative blood loss ≥4900 mL, and intra-operative blood transfusion ≥10 units were the significant factors to predict massive transfusion in the SICUs.

Supplemental oxygen for caesarean section during regional anaesthesia.

BACKGROUND: Supplementary oxygen is routinely administered to low-risk pregnant women during an elective caesarean section under regional anaesthesia; however, maternal and foetal outcomes have not been well established. This is an update of a review first published in 2013. OBJECTIVES: The primary objective was to determine whether supplementary oxygen given to low-risk term pregnant women undergoing elective caesarean section under regional anaesthesia can prevent maternal and neonatal desaturation. The secondary objective was to compare the mean values of maternal and neonatal blood gas levels between mothers who received supplementary oxygen and those who did not (control group). SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, issue 11), MEDLINE (1948 to November 2014) and EMBASE (1980 to November 2014). The original search was first performed in February 2012. We reran the search in CENTRAL, MEDLINE, EMBASE in February 2016. One potential new study of interest was added to the list of 'Studies awaiting Classification' and will be incorporated into the formal review findings during the next review update. SELECTION CRITERIA: We included randomized controlled trials (RCTs) of low-risk pregnant women undergoing an elective caesarean section under regional anaesthesia and compared outcomes with, and without, oxygen supplementation. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data, assessed methodological quality and performed subgroup and sensitivity analyses. MAIN RESULTS: We found one new included study in this updated version. In total, our updated review includes 11 trials (with 753 participants). The low quality of evidence showed no significant differences in average Apgar scores at one minute (N = six trials, 519 participants; 95% confidence (CI) -0.16 to 0.31, P = 0.53) and at five minutes (N = six trials, 519 participants; 95% CI -0.06 to 0.06, P = 0.98). None of the 11 trials reported maternal desaturation. The very low quality of evidence showed that in comparison to room air, women in labour receiving supplementary oxygen had higher maternal oxygen saturation (N = three trials, 209 participants), maternal PaO2 (oxygen pressure in the blood; N = six trials, 241 participants), UaPO2 (foetal umbilical arterial blood; N = eight trials, 504 participants; 95% CI 1.8 to 4.9, P < 0.0001) and UvPO2 (foetal umbilical venous blood; N = 10 trials, 683 participants). There was high heterogeneity among these outcomes. A subgroup analysis showed no significant difference in UaPO2 between the two intervention groups in low-risk studies, whereas the high-risk studies showed a benefit for the neonatal oxygen group. AUTHORS' CONCLUSIONS: Overall, we found no convincing evidence that giving supplementary oxygen to healthy term pregnant women during elective caesarean section under regional anaesthesia is either beneficial or harmful for either the mother or the foetus' short-term clinical outcome as assessed by Apgar scores. Although, there were significant higher maternal and neonatal blood gas values and markers of free radicals when extra oxygen was given, the results should be interpreted with caution due to the low grade quality of the evidence.

Cost of Critically Ill Surgical Patients in Thailand: A Prospective Analysis of a Multicenter THAI-SICU Study.

Objective: To quantify the total cost per admission and daily cost of critically ill surgical patients and cost attributable to Acute Physiologic Assessment and Chronic Health Evaluation (APACHE) II score, invasive mechanical ventilation and major complications in surgical intensive care unit (SICU) including sepsis, acute respiratory distress syndrome (ARDS), acute lung injury (ALI), acute kidney injury (AKI), cardiac arrest, and myocardial infarction. Material and Method: A multicentre, prospective, observational, cost analysis study was carried out in SICU of five university hospitals in Thailand. Patients of age over 18 admitted to SICU (more than 6 hours) from 18 April 2011 to 30 November 2012 were recruited.The total SICU cost per admission (in Thai baht currency year 2011-2012) were recorded using hospital accounting database. Average daily SICU cost was calculated from total ICU cost divided by the ICU length of stay. The occurrence of sepsis, major cardiac and respiratory complications and duration of invasive mechanical ventilation were studied. Results: A total of 3,055 patients with 12,592 ICU-days admitted to SICU during the study period. The median (IQR) ICU- length of stay was 2 (1, 4) days. The median (IQR) total SICU cost per admission was 44,055 (29,950-73,694) Thai baht. The median (IQR) daily cost was 18,777 (13,650-22,790) Thai baht. There was a variation of total and daily SICU cost across ICUs. For each of APACHE II score increases, cost increases with a median (IQR) of 1,731.755 (1,507.418-1,956.093) Thai baht. Invasive mechanically ventilated patients had higher cost than non-ventilated patients with a median (IQR) 15,873.4 (15,631.13-16,115.67) Thai baht. The patient with any complications listed here (sepsis, ARDS, ALI, AKI, myocardial infarction) had higher costs of care than ones who had none. Conclusion: Cost of critically ill surgical patients in the public university hospital in Thailand was varied. The complications occurred in ICU increased the cost. To quantify the resource consumption of individual patient admitted to SICU, the costing method and cost components must be verified.

Modalities in Venous Thromboembolism Prophylaxis and Symptomatic Venous Thromboembolism Occurrence in Critically Ill Surgical Patients (THAI-SICU Study).

Objective: This report aimed to demonstrate the current modality of venous thrombomebolism (VTE) prophylaxis at the University-based critical, surgical care units (SICUs) and the occurrence of VTE during SICUs admission. Material and Method: The data were analyzed from a multicenter prospective observational study that was conducted in 9 university based SICUs in Thailand (THAI-SICU study). VTE prophylaxis and occurrence were recorded daily and VTE events which included deep vein thrombosis (DVT) and pulmonary embolism (PE) were collected only after symptomatic events occurred and confirmed the diagnosis by Doppler ultrasonographic examination or other imaging modalities. Results: A total of 385 in 4,652 cases (8.3%) received VTE prophylaxis. The modalities of VTE prophylaxis were significant difference depended on the admission diagnosis, patient age, and severity of diseases. The result of total VTE occurrence was 18 patients (0.4%) and mortality was 4 in 18 patients (22.2%). Of these, DVT occurred in 14 patients (0.3%) and mortality was 3 of 14 patients (21.4%), and the PE occurred in 4 patients (0.1%) and mortality was 1 of 4 patients (25.0%). Conclusion: The VTE prophylaxis rate was low in Thai University based SICUs. Although the overall incidence of symptomatic VTE in the SICUs low, the mortality rate was high in this cohort.

Incidence, Outcomes and Risk Factors for Mortality of Symptomatic upper Gastrointestinal Hemorrhage in Surgical Critical Ill Patients (THAI SICU Study).

Objective: This multicenter university-based study reports the incidence, outcomes and defined risk factors for mortality of upper gastrointestinal hemorrhage (UGIH) patients in the surgical intensive care units (ICU) patients in Thailand. Material and Method: This is part of a multicenter prospective observational study in the ICU in Thailand (THAI-SICU study). Patients who had a clinical presentation of upper gastrointestinal hemorrhage or an endoscopic diagnosis from April 2011 to January 2013 were enrolled into this sub-study. Results: A total of 4,652 patients were analyzed. Fifty-five patients (1.18%) had symptomatic UGIH during ICU admission. The median age (interquartile range, IQR) was 72 (63-78) years old and the median APACHE II score (IQR) was 17 (13-22). In a comparison between the UGIH patients who survived and those who non-survived APACHE II score were higher in the non-survivors. The ICU mortality rate and 28-day mortality rate in these patients were 30.91% and 40%, respectively. In multivariable model, UGIH was significantly associated with 28-day mortality [adjusted odds ratio, OR, (95% confidence interval, CI): 1.99 (1.02 to 3.88); p = 0.043] and ICU length of stay [adjusted coefficient (95% CI): 9.36 (8.03 to 10.70); p<0.001]. Regarding the exploratory model, the significant risk factors for non-survived of UGIH patients were coagulopathy especially platelet count <50,000 [OR (95% CI): 3.96 (1.07-14.67); p = 0.039] and INR >1.5 [5 (1.04-23.98); p = 0.044], renal failure [6.48 (1.37-30.61); p = 0.018], APACHE II score [1.11 (1.02-1.22); p = 0.020] and vasopressor use [5.78 (1.6-37.18); p = 0.013]. Conclusion: The incidence of symptomatic UGIH in the THAI-SICU study was 1.18% and UGIH was associated with higher 28-day mortality rate and prolonged ICU length of stay. The risk factors for mortality were coagulopathy, renal failure, APACHE II score and vasopressor use.

Incidence and Prognostic Factors for Mortality of Abdominal Hypertension in Critically Ill Surgical Patients in THAI-SICU Study.

Objective: This study aimed to investigate the incidence and prognostic factors of mortality in intra-abdominal hypertension that developed during admission in the surgical intensive care units in Thailand. Material and Method: This was a prospective observational study in nine university-based surgical intensive care units in Thailand. (THAI-SICU) The suspected patients who had the intra-abdominal pressure more than 12 mmHg were defined as intra-abdominal hypertension (IAH). The patients were followed until discharge. Results: Among 4,652 cases, a total of 71 cases (1.5%) developed IAH. The average age was 53.05+20.26 years. The median APACHE II score was 13 (9-15). Eighteen patients received surgical decompression as treatment. Metabolic acidosis (pH <7.2) and abdominal aortic surgery were the significant factors for mortality in intra-abdominal hypertension patients. Conclusion: The incidence of intra-abdominal hypertension in the critical surgical care units was low in this cohort. Intraabdominal hypertension in patients who previously received abdominal aortic surgery and who had concomitant acidosis was the independent risk factor of mortality.

Incidence of and Risk Factors for Acute Respiratory Distress Syndrome in Patients Admitted to Surgical Intensive Care Units: The Multicenter Thai University- Based Surgical Intensive Care Unit (THAI-SICU) Study.

Objective: The incidence and outcomes of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) are unclear. We evaluated the cumulative incidence of, risk factors for, and outcomes of ALI/ARDS in surgical ICUs (SICUs). Material and Method: The multicenter Thai University-based Surgical Intensive Care Unit (THAI-SICU) study was a prospective, observational cohort study including nine university-based SICUs throughout Thailand from April 2011 to January 2013. All >18-year-old surgical patients who were admitted to general SICUs were recruited. The primary outcome was the incidence of ALI/ARDS. Results: In total, 4,652 patients were analyzed. ALI/ARDS new developed in 114 patients (2.5%). Patients with ALI/ARDS had higher APACHE II (20.0 vs. 11.4, respectively; p<0.001) and SOFA scores (7.3 vs. 3.1, respectively; p<0.001) and a higher incidence of past or current smoking (48% vs. 36%, respectively; p<0.001) than the non-ARDS patients. The 28-day mortality rate was significantly higher in patients with than without ALI/ARDS (50% vs. 12%; p<0.001). Higher APACHE II and SOFA scores and higher rates of current or past smoking were independent predictors of ALI/ARDS. Conclusion: The incidence of ALI/ARDS in the THAI-SICU study was low, but the mortality rate was high. Higher severity scores and smoking were associated with ALI/ARDS.

A Multi-Center Thai University-Based Surgical Intensive Care Units Study (THAI-SICU Study): Outcome of ICU Care and Adverse Events.

Objective: Surgical intensive care units (SICUs) are special units for critically ill surgical patients both in the pre and postoperative period. There is little aggregated information about surgical patients who are admitted to the Thai surgical ICU. The objective of this report was to describe patient characteristics, outcomes of ICU care, incidence and outcomes of adverse events in the SICU in the participating SICUs. Material and Method: This multi-center, prospective, observational study of nine university-based SICUs was done. All admitted patients with ages >18 years old were included. Information about patient characteristics, underlying medical problems, indication and type of ICU admission, severity score as ASA physical status in operative patients, APACHE II score and SOFA score, adverse events of interest, ventilator days, ICU and 28 days mortality. The association of outcome and predictors was reported by relative risk (RR) with 95% confidence interval (95% CI). Statistical significant difference was defined by p<0.05. Results: During April 2011-January 2013 of total cohort time, a total of 4,652 patients from nine university-based SICUs were included in this study. Mode of patient age was 71-75 year old for both sexes. Median (IQR) of APACHE II scores and SOFA scores were 10 (7-10) and 2 (1-5), respectively. Seventy eight percent of patients were postoperative patients and 50% of them were ASA physical status III. The median of ICU stay was 2 (IQR 1-4) days. Each day of ICU increment was associated with increased 1.4 days of a hospital stay. Three percent of survived at discharge were clinically inappropriate discharge resulting in ICU readmission. Sixty-five percent were discharged home after ICU admission. ICU and 28 days mortality was 9.6% and 13.8%. The seven most common adverse events were sepsis (19.5%), acute kidney injury (AKI) (16.9%), new cardiac arrhythmias (6.2%), acute respiratory distress syndrome (ARDS) (5.8%), cardiac arrest (4.9%), delirium (3.5%) and reintubation within 72 hours (3.0%), respectively. Most of the adverse events occurred in the first five days, significantly less occurred after 15 days of ICU admission. The association between adverse events and 28 days mortality were significant for cardiac arrest (RR, 9.5; 95% CI, 8.6-10.4), respiratory failure [acute respiratory distress syndrome (ARDS) (RR, 4.6; 95% CI, 3.9-5.3), acute lung injury (ALI) (RR, 2.7; 95% CI, 2.1-3.6)], acute kidney injury (AKI) (RR, 4.2; 95% CI, 3.7-4.8), sepsis (RR, 3.6; 95% CI, 3.2-4.2), iatrogenic pneumothorax (RR, 3.2; 95% CI, 2.1-5.1), new seizure (RR, 3.1, 95% CI, 2.2-4.4), upper GI hemorrhage (RR, 3.0, 95% CI, 2.1-4.1), new cardiac arrhythmias (RR, 2.9; 95% CI, 2.4-3.5), delirium (RR, 2.1; 95% CI, 1.7-2.8), acute myocardial infarction (RR, 2.1; 95% CI, 1.4-3.1), unplanned extubation (RR, 2.1; 95% CI, 1.4-3.1), intra-abdominal hypertension (RR, 1.8; 95% CI, 1.2-2.7) and reintubation within 72 hours (RR, 1.5; 95% CI, 1.1-2.1). Conclusion: This is the first large study of surgical critical care in Thailand, which had a systematic patient follow-up program. Most of the patients were elderly. Adverse events were most frequent during the first 5 days of admission and were associated with ICU and 28 days mortality.

A multi-center Thai university-based surgical intensive care units study (THAI-SICU study): methodology and ICU characteristics.

OBJECTIVE: Although there were two large intra-operative observational studies on Thai surgical patients (THAI and THAI-AIMS), there has been no available study on critically ill surgical patients regarding their adverse events and outcomes. A THAI-Surgical Intensive Care Unit (SICU) study has been established for monitoring the occurrence of these adverse events and outcomes in the SICU. The objective of this report is to describe the methodology of the THAI-SICU study and participating SICUs' characteristics as well as the early recruitment results on patients enrolled in the present study. MATERIAL AND METHOD: The present study is designed as a multi-center, prospective, observational study. This report describes the method of case record form development and summarizes their collected parameters as well as the adverse event surveillance variables. All of nine SICU characteristics are described regarding their management systems, physicians' and nurses' work patterns. The final group of enrolled patients is reported. RESULTS: A total of nine university-based SICUs were included in the present study. All participating hospitals are residency training centers. Four of the SICUs, fulltime directors are anesthesiologists. Only one hospital's SICU is directed by a surgeon. Two SICUs were closed ICUs, three were mandatory consulting units, one was an elective consultation unit and the remaining three ICUs had no directors. Most of the participating SICUs had heterogeneity of surgical specialty patients. Six SICUs had regular resident rotations and only two of the SICUs had critical care fellowship training. There were significant differences regarding the nursing workload among the ICUs. The patient to registered nurse ratio ranged from 0.9-2.0. After a total of 19.7 months of a recruitment period, the total number of patient admissions was 6,548 (1,894 patients were excluded). A total cohort of 4,654 patients was included for further analytical processes. CONCLUSION: There were differences in ICU management systems, physician and specialist coverage, nurse burdens, nurse sparing, and types of patients admitted in the university based SICUs. This presentation is the pioneer multi-center study on Thai SICUs in which adverse events and outcomes are reported.

Supplemental oxygen for caesarean section during regional anaesthesia.

BACKGROUND: Supplementary oxygen is routinely administered to low-risk pregnant women during an elective caesarean section under regional anaesthesia; however, maternal and foetal outcomes have not been well established. OBJECTIVES: The primary objective was to determine whether supplementary oxygen given to low-risk term pregnant women undergoing elective caesarean section under regional anaesthesia can prevent maternal and neonatal desaturation. The secondary objective was to compare the mean values of maternal and neonatal blood gas levels between mothers who received supplementary oxygen and those who did not (control group). SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 2, 2012), MEDLINE (1948 to February 2012) and EMBASE (1980 to February 2012). We did not apply language restrictions. SELECTION CRITERIA: We included randomized controlled trials of low-risk pregnant women undergoing an elective caesarean section under regional anaesthesia and compared outcomes with, and without, oxygen supplementation. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data, assessed methodological quality and performed subgroup and sensitivity analyses. MAIN RESULTS: We included 10 trials with a total of 683 participants. Supplementary oxygen administration varied widely in dose and duration between trials. No cases of maternal desaturation were reported, although none of the 10 trials focused on maternal desaturation. Significant differences were noted in maternal oxygen saturation (higher with oxygen, N = three trials; mean difference (MD) 1.6%, 95% confidence interval (CI) 0.8 to 2.3, P < 0.0001), maternal PaO2 (oxygen pressure in the blood; higher with oxygen, N = six trials; MD 141.8 mm Hg, 95% CI 109.3 to 174.3, P < 0.00001), neonatal UaPO2 (foetal umbilical arterial blood; higher with oxygen, N = eight trials; MD 3.3 mm Hg, 95% CI 1.8 to 4.9, P < 0.0001) and UvPO2 (foetal umbilical venous blood; higher with oxygen, N = 10 trials; MD 5.9 mm Hg, 95% CI 3.2 to 8.5, P < 0.0001). No significant differences were reported in neonatal UapH (N = eight trials; MD 0.00, 95% CI -0.01 to 0.00, P = 0.26) and in average Apgar scores at one minute (N = five trials; MD 0.07, 95% CI -0.20 to 0.34, P = 0.6) and at five minutes (N = five trials; MD 0.00, 95% CI -0.06 to 0.05, P = 0.91).Only two out of 10 trials had a low risk of bias in all categories. When we separated the studies into low risk and high risk for bias, we found substantial statistical heterogeneity. None of the low-risk studies showed a significant difference in neonatal UaPO2 between the two intervention groups, whereas the high-risk studies showed a benefit for the neonatal oxygen group.The level of oxygen free radicals (malondialdehyde (MDA) and 8-isoprostane) was higher in participants who received supplementary oxygen (N = two trials; MD 0.2 µmol/L, 95% CI 0.1 to 0.4, P = 0.0002; MD 64.3 pg/mL, 95% CI 51.7 to 76.8, P < 0.00001, respectively). AUTHORS' CONCLUSIONS: Current evidence suggests that supplementary oxygen given to healthy term pregnant women during elective caesarean section under regional anaesthesia is associated with higher maternal and neonatal oxygen levels (maternal SpO2, PaO2, UaPO2 and UvPO2) and higher levels of oxygen free radicals. However, the intervention was neither beneficial nor harmful to the neonate's short-term clinical outcome as assessed by Apgar scores.

Position of exhalation port and mask design affect CO2 rebreathing during noninvasive positive pressure ventilation.

OBJECTIVE: Noninvasive positive pressure ventilation may be considered a first line intervention to treat patients with hypercapnic respiratory failure. However, CO2 rebreathing from the ventilator circuit or mask may impair CO2 elimination and load the ventilatory muscles. This study was conducted to evaluate the effect of exhalation port location and mask design on CO2 rebreathing during noninvasive positive pressure ventilation. DESIGN: Lung model evaluation. SETTING: Experimental laboratory of a large university-affiliated hospital. SUBJECTS: A dual-chamber test lung was used to simulate the ventilatory mechanics of a patient with obstructive lung disease. INTERVENTION: Hypercapnic respiratory failure (end-tidal CO2 of 75 mm Hg) and obstructive lung disease were simulated in a double-chamber lung model. A facial mask (inner volume of 165 mL) with exhalation port within the mask (Facial-MEP) or the same mask with exhalation port in the ventilator circuit (Facial-WS) and a total face mask with exhalation port within the mask (inner volume 875 mL, Total Face) were tested during continuous positive airway pressure and pressure support ventilation provided by a single-limb circuit ventilator at the same frequency and tidal volume. MEASUREMENTS AND MAIN RESULTS: A capnometer and a flow transducer were placed in the lung model upper airway to measure the volume of CO2 rebreathed and tidal volume (Vt). The inspiratory load was estimated from the pressure variation in the lung model driving chamber (PDR). Volume of CO2 rebreathed was smaller during Facial-MEP compared with the other masks in all tested conditions (p <.001). The Vt and PDR necessary to decrease end-tidal CO2 20% (from 75 to 60 mm Hg) was different among the tested masks (Facial-MEP, Vt 701 +/- 9 mL, PDR 8.1 +/- 0.1 cm H2O/sec; Facial-WS, Vt 745 +/- 9 mL, PDR 10.2 +/- 0.1 cm H2O/sec; Total Face, Vt 790 +/- 12 mL, PDR 11.4 +/- 0.2 cm H2O/sec, p <.001). CONCLUSION: Facial-MEP with its exhalation port within the mask and the smallest mask volume demonstrated less rebreathed CO2 and a lower PDR than either the Facial-WS or Total Face masks. Additional studies are necessary to confirm if mask design can clinically affect patient's inspiratory effort during noninvasive positive pressure ventilation.

In vitro evaluation of aerosol bronchodilator delivery during noninvasive positive pressure ventilation: effect of ventilator settings and nebulizer position.

OBJECTIVE: Respiratory failure due to exacerbation of obstructive lung disease has been successfully treated with noninvasive positive pressure ventilation (NPPV). However, there have been no reports of factors affecting aerosol delivery during NPPV. Our objective was to determine the effect of ventilator settings and nebulizer position on albuterol delivery during NPPV. DESIGN: Bench model study. SETTING: University laboratory. SUBJECTS: None. INTERVENTIONS: A Respironics BiPAP S/T-D30 with a standard circuit was attached to a lung model simulating spontaneous breathing. Inspiratory/expiratory pressures of 10/5, 15/5, 20/5, 15/10, 20/10, and 25/10 cm H2O were tested at respiratory rates of 10 and 20/min. A nebulizer was filled with 5 mg of albuterol in 4 mL of solution, driven with 8 L/min oxygen, and placed at either a proximal (ventilator outlet) or distal (between leak port and lung model connection) position. Albuterol delivery was estimated by measuring the amount of the albuterol collected on a filter placed at the inlet of the lung model. MEASUREMENT AND MAIN RESULTS: Albuterol delivery varied from 5.2 +/- 0.4% to 24.5 +/- 1.3% of the nominal dose and was significantly affected by the position of the nebulizer, respiratory rate, and BiPAP settings (p <.001 in each case). The greatest albuterol delivery was observed with the nebulizer operating at the distal position and a respiratory rate of 20/min. At this respiratory rate and nebulizer placement, albuterol delivery increased with increasing inspiratory pressure levels and decreased as expiratory pressure levels were increased. Nebulizer flow did not affect function of the ventilator. CONCLUSIONS: At optimum nebulizer position (between the leak port and patient connection) and ventilator settings (high inspiratory pressure and low expiratory pressure), as much as 25% of the nominal albuterol dose may be delivered during NPPV.