Evaluation of a training programme for critical incident debrief facilitators.

BACKGROUND: Critical incident debriefs are a commonly used occupational health tool for supporting staff after traumatic work incidents. However, there is a dearth of literature evaluating training programmes for debrief facilitators. AIMS: To evaluate a 5-day training programme to equip healthcare, social care and voluntary, community and social enterprise sector staff to act as post-incident peer supporters and debrief facilitators. METHODS: A mixed-methods, single-arm, before-and-after study. Data were collected at baseline and post-training. The quantitative outcome measure was 'Confidence'; the sum of two items measuring confidence in (i) supporting peers after critical incidents and (ii) facilitating post-incident structured team discussions. At post-training, quantitative and qualitative feedback regarding experiences and perceptions of the training was also gathered. RESULTS: We recruited 45 participants between October 2021 and January 2022. Confidence in supporting peers following incidents and facilitating post-incident structured team discussions increased significantly following the training, t(35) = -6.77, P < 0.001. A majority of participants reported they would do things differently because of the training and that they found the training relevant, useful and engaging. Summative content analysis of qualitative feedback indicated that participants (i) believed the role plays were an important learning tool and (ii) thought it was important that the trainer was engaging. Some participants would have preferred in-person delivery. CONCLUSIONS: Participants valued training in post-incident peer support and debriefing skills. Organizations implementing post-incident support pathways could usefully include this training and ensure optimal uptake and engagement by (i) providing in-person and online delivery options and (ii) including role play as a learning technique.

Multidetector computed tomographic pulmonary angiography in patients with a high clinical probability of pulmonary embolism.

UNLABELLED: ESSENTIALS: When high probability of pulmonary embolism (PE), sensitivity of computed tomography (CT) is unclear. We investigated the sensitivity of multidetector CT among 134 patients with a high probability of PE. A normal CT alone may not safely exclude PE in patients with a high clinical pretest probability. In patients with no clear alternative diagnosis after CTPA, further testing should be strongly considered. BACKGROUND: Whether patients with a negative multidetector computed tomographic pulmonary angiography (CTPA) result and a high clinical pretest probability of pulmonary embolism (PE) should be further investigated is controversial. METHODS: This was a prospective investigation of the sensitivity of multidetector CTPA among patients with a priori clinical assessment of a high probability of PE according to the Wells criteria. Among patients with a negative CTPA result, the diagnosis of PE required at least one of the following conditions: ventilation/perfusion lung scan showing a high probability of PE in a patient with no history of PE, abnormal findings on venous ultrasonography in a patient without previous deep vein thrombosis at that site, or the occurrence of venous thromboembolism (VTE) in a 3-month follow-up period after anticoagulation was withheld because of a negative multidetector CTPA result. RESULTS: We identified 498 patients with a priori clinical assessment of a high probability of PE and a completed CTPA study. CTPA excluded PE in 134 patients; in these patients, the pooled incidence of VTE was 5.2% (seven of 134 patients; 95% confidence interval [CI] 1.5-9.0). Five patients had VTEs that were confirmed by an additional imaging test despite a negative CTPA result (five of 48 patients; 10.4%; 95% CI 1.8-19.1), and two patients had objectively confirmed VTEs that occurred during clinical follow-up of at least 3 months (two of 86 patients; 2.3%; 95% CI 0-5.5). None of the patients had a fatal PE during follow-up. CONCLUSIONS: A normal multidetector CTPA result alone may not safely exclude PE in patients with a high clinical pretest probability.

Prognostic significance of tricuspid annular displacement in normotensive patients with acute symptomatic pulmonary embolism.

BACKGROUND: Tricuspid annular plane systolic excursion (TAPSE) is an emerging prognostic indicator in patients with acute symptomatic pulmonary embolism (PE). METHODS AND RESULTS: We prospectively examined 782 normotensive patients with PE who underwent echocardiography in a multicenter study. As compared with patients with a TAPSE of > 1.6 cm, those with a TAPSE of ≤ 1.6 cm had increased systolic pulmonary artery pressure (53.7 ± 16.7 mmHg vs. 40.0 ± 15.5 mmHg, P < 0.001), right ventricle (RV) end-diastolic diameter (3.5 ± 0.8 cm vs. 3.0 ± 0.6 cm, P < 0.001), and RV to left ventricle end-diastolic diameter ratio (1.0 ± 0.3 vs. 0.8 ± 0.2, P < 0.001), and a higher prevalence of RV free wall hypokinesis (68% vs. 11%, P < 0.001). Patients with a TAPSE of ≤ 1.6 cm at the time of PE diagnosis were significantly more likely to die from any cause (hazard ratio [HR] 2.3; 95% confidence interval [CI] 1.2-4.7; P = 0.02) and from PE (HR 4.4; 95% CI 1.3-15.3; P = 0.02) during follow-up. In an external validation cohort of 1326 patients with acute PE enrolled in the international multicenter Registro Informatizado de la Enfermedad TromboEmbólica, a TAPSE of ≤ 1.6 cm remained a significant predictor of all-cause mortality (HR 2.1; 95% CI 1.3-3.2; P = 0.001) and PE-specific mortality (HR 2.5; 95% CI 1.2-5.2; P = 0.01). CONCLUSIONS: In normotensive patients with PE, TAPSE reflects right ventricular function. For these patients, TAPSE is independently predictive of survival.

Thrombolytic therapy and outcome of patients with an acute symptomatic pulmonary embolism.

BACKGROUND: While the primary therapy for most patients with a pulmonary embolism (PE) consists of anticoagulation, the efficacy of thrombolysis relative to standard therapy remains unclear. METHODS: In this retrospective cohort study of 15,944 patients with an objectively confirmed symptomatic acute PE, identified from the multicenter, international, prospective, Registro Informatizado de la Enfermedad TromboEmbólica (RIETE registry), we aimed to assess the association between thrombolytic therapy and all-cause mortality during the first 3 months after the diagnosis of a PE. After creating two subgroups, stratified by systolic blood pressure (SBP) (< 100 mm Hg vs. other), we used propensity score-matching for a comparison of patients who received thrombolysis to those who did not in each subgroup. RESULTS: Patients who received thrombolysis were younger, had fewer comorbid diseases and more signs of clinical severity compared with those who did not receive it. In the subgroup with systolic hypotension, analysis of propensity score-matched pairs (n = 94 pairs) showed a non-statistically significant but clinically relevant lower risk of death for thrombolysis compared with no thrombolysis (odds ratio [OR] 0.72; 95% confidence interval [CI], 0.36-1.46; P = 0.37). In the normotensive subgroup, analysis of propensity score-matched pairs (n = 217 pairs) showed a statistically significant and clinically meaningful increased risk of death for thrombolysis compared with no thrombolysis (OR 2.32; 95% CI, 1.15-4.68; P = 0.018). When we imputed data for missing values for echocardiography and troponin tests in the group of normotensive patients, we no longer detected the increased risk of death associated with thrombolytic therapy. CONCLUSIONS: In normotensive patients with acute symptomatic PE, thrombolytic therapy is associated with a higher risk of death than no thrombolytic therapy. In hemodynamically unstable patients, thrombolytic therapy is possibly associated with a lower risk of death than no thrombolytic therapy. However, study design limitations do not imply a causal relationship between thrombolytics and outcome.

The shock index and the simplified PESI for identification of low-risk patients with acute pulmonary embolism.

We compared the test characteristics of the shock index (SI) and the simplified pulmonary embolism severity index (sPESI) for predicting 30-day outcomes in a cohort of 1,206 patients with objectively confirmed pulmonary embolism (PE). The primary outcome of the study was all-cause mortality. The secondary outcome was nonfatal symptomatic recurrent venous thromboembolism (VTE) or nonfatal major bleeding. Overall, 119 (9.9%) out of 1,206 patients died (95% CI 8.2-11.5%) during the first month of follow-up. The sPESI classified fewer patients as low-risk (369 (31%) out of 1,206 patients, 95% CI 28-33%) compared to the SI (1,024 (85%) out of 1,206 patients, 95% CI 83-87%) (p<0.001). Low-risk patients based on the sPESI had a lower 30-day mortality than those based on the SI (1.6% (95% CI 0.3-2.9%) versus 8.3% (95% CI 6.6-10.0%)), while the 30-day rate of nonfatal recurrent VTE or major bleeding was similar (2.2% (95%CI 0.7-3.6%) versus 3.3% (95%CI 2.2-4.4%)). The net reclassification improvement with the sPESI was 13.4% (p = 0.07). The integrated discrimination improvement was estimated as 1.8% (p<0.001). The sPESI quantified the prognosis of patients with PE better than the SI.

Pulmonary Embolism Severity Index and troponin testing for the selection of low-risk patients with acute symptomatic pulmonary embolism.

BACKGROUND: The combination of the Pulmonary Embolism Severity Index (PESI) and troponin testing could help physicians identify appropriate patients with acute pulmonary embolism (PE) for early hospital discharge. METHODS: This prospective cohort study included a total of 567 patients from a single center registry with objectively confirmed acute symptomatic PE. On the basis of the PESI, each patient was classified into one of five classes (I-V). At the time of hospital admission, patients had troponin I (cTnI) levels measured. The endpoint of the study was all-cause mortality within 30 days after diagnosis. We calculated the mortality rates in four patient groups: group 1, PESI class I-II plus cTnI < 0.1 ng mL(-1); group 2, PESI classes III-V plus cTnI < 0.1 ng mL(-1); group 3, PESI classes I-II plus cTnI > or = 0.1 ng mL(-1); and group 4, PESI classes III-V plus cTnI > or = 0.1 ng mL(-1). RESULTS: The study cohort had a 30-day mortality of 10% [95% confidence interval (CI), 7.6-12.5%]. Mortality rates in the four groups were 1.3%, 14.2%, 0% and 15.4%, respectively. Compared with non-elevated cTnl, the low-risk PESI had a higher negative predictive value (NPV) (98.9% vs. 90.8%) and negative likelihood ratio (NLR) (0.1 vs. 0.9) for predicting mortality. The addition of non-elevated cTnI to low-risk PESI did not improve the NPV or the NLR compared with either test alone. CONCLUSIONS: Compared with cTnl testing, PESI classification more accurately identified patients with PE who are at low risk of all-cause death within 30 days of presentation.

Rare primary CNS anaplastic large cell lymphoma in an immunocompetent adult: a clinical-pathologic case report and review case of the literature.

OBJECTIVE AND IMPORTANCE: Isolated anaplastic large cell lymphoma (ALCL) presenting in the primary central nervous system is distinctly uncommon. The authors describe a case that clinically and radiographically simulated a primary glial neoplasm. CLINICAL PRESENTATION: A 39-year-old immunocompetent male presented with seizures and a rapidly enlarging right occipital/parietal lesion. Magnetic resonance images demonstrated a right occipitoparietal lesion, hypodense on T1WI, with patchy contrast enhancement with gadolinium and significant white matter edema pattern on T2WI along with mass effect and midline shift. INTERVENTION: The patient underwent a frameless stereotactic assisted needle biopsy. There appeared to be a clear demarcation between white matter and tumor with no obvious necrosis. Biopsy showed a proliferation of single cells and poorly cohesive groups of cells with large, pleomorphic nuclei, many containing prominent nucleoli, and a moderate amount of cytoplasm. Immunohistochemical staining revealed CD-30 and ALK-positivity typical of ALCL, a rare form of T-cell lymphoma. An extensive workup revealed neither systemic disease nor evidence of immunocompromise. CONCLUSION: Reported in less than 20 patients, primary ALCL in an immunocompetent patient is rarely found intracranially; however, its ability to mimic glial neoplasms as well as other pathologies underlines its importance.

Pain management program follow-ups. a national survey of current practice in the United Kingdom.

In the United Kingdom (UK), the number of multidisciplinary pain management programs (PMP) has sharply increased in the last decade. Treatment aims to effect long-term changes, yet arrangements for evaluating long-term treatment outcome in routine practice remain unknown. All PMPs identified in the UK were invited to provide information by mailed questionnaire on aspects of follow-up evaluation. Sixty-six of 70 PMPs identified were successfully contacted (94% response rate). Ten of 48 PMPs (21%) provided complete data and met suggested criteria for adequate length and rates of follow-up, and outcome measurement. Levels of staffing and content explained only a proportion of the variability seen. A general commitment to follow-up outcome evaluation by PMPs was identified but there was substantial variability among programs in length of follow-up, attendance rates, and outcome measurement. These findings raise issues about the consistency of follow-up evaluation across the UK and the ability of current arrangements in some PMPs to accurately determine the longer-term outcome of chronic pain patients. Incorporating follow-ups into existing desirable criteria and agreeing on core outcome measures are two options available to service providers.

Alveolar hemorrhage and pulmonary hypertension in systemic sclerosis: a continuum of scleroderma renal crisis?

Alveolar hemorrhage occurs as a complication of systemic inflammatory diseases. In addition to alveolar hemorrhage, patients with systemic sclerosis (SSc) may suffer from digital infarction, pulmonary hypertension, and renal crisis. Although a common pathogenesis of this disease that explains the variety of problems during a patient's illness has yet to be identified, the unique characteristics of SSc may alter our approach to alveolar hemorrhage in this patient population. We describe a patient with SSc, who presented with pulmonary hypertension and alveolar hemorrhage complicated by features suggesting re-occurrence of scleroderma renal crisis. Our successful management of this patient, with complications that are usually of high morbidity, may be attributed to our judicious use of glucocorticosteroid therapy and maximization of angiotensin-converting enzyme inhibition. In view of the potential for glucocorticoids to precipitate scleroderma renal crisis, we suggest caution in the use of these medications for manifestations that may be similar in their pathogenesis.

Vena caval filters in pulmonary embolism.

Since the early 1900s, surgical interruption of the inferior vena cava (IVC) has been utilized in the management of venous thromboembolism (VTE). With the advent of newer-generation percutaneous devices in the late 1970s, their use and indications have expanded. The literature to support their efficacy, however, is limited to several case series and a single randomized controlled trial. Despite this, some have advocated the use of IVC filters as primary treatment of VTE in certain patient populations. In addition, there has been a large amount of interest in their use as prophylaxis against pulmonary embolism (PE) in high-risk patients. In the past 10 years, we have also seen the development and initial use of temporary devices, although their role in the management of this disease is even less certain. This article will review the recent literature on efficacy, complications, and indications for the use of IVC filters in the prevention and treatment of PE.

Smoking and postoperative pulmonary complications. An evidence-based review of the recent literature.

Postoperative pulmonary complications (PPC) lead to significant morbidity after both thoracic and non-thoracic surgical procedures. The role of smoking as an independent risk factor is controversial, though recent level III and IV studies suggest that it may indeed be significant. In addition, the role and timing of pre-operative smoking cessation is not clear. Although some studies suggest that abstinence too soon prior to operation may actually increase the risk of PPC, it still appears that aggressive counseling for smoking cessation prior to any elective procedure is the best overall course of action.

An engraftment syndrome in autologous stem cell transplantation related to mononuclear cell dose.

Engraftment syndrome (ES) is a toxicity of autologous stem cell transplantation that occurs unexpectedly and is occasionally fatal. This syndrome, manifested as fever, rash and pulmonary deterioration which becomes evident at marrow engraftment, has been described by several centers but as yet remains enigmatic. We describe this syndrome at a single institution and note that it has accompanied the transition from the use of autologous marrow rescue to peripheral blood stem cell rescue. In this study, the occurrence of ES is related to the mononuclear cell dose at reinfusion. We found, in agreement with other reports, that patients developing ES are predominantly women undergoing therapy for solid tumors who demonstrate neutrophil engraftment at a significantly greater rate than do those patients not expressing the syndrome. We did not note a significant relationship between growth factor use (G-CSF) or amphotericin B exposure and the syndrome, as has been previously reported. The progenitor cell populations obtained with autologous marrow and peripheral blood stem cells are different. We hypothesize that the interaction of committed myeloid precursors from the stem cell product with the pulmonary vascular endothelium can be deleterious, especially under the influence of the inflammatory cytokines present at the time of engraftment.

Mechanical ventilation in hematopoietic stem cell transplantation: can We effectively predict outcomes?

BACKGROUND: Survival rates from mechanical ventilation (MV) in allogeneic bone marrow transplantation are poor, but little is known about the need for and outcomes from MV in patients who undergo autologous hematopoietic stem cell transplantation (AHSCT). STUDY OBJECTIVE: To determine the frequency of and risk factors for the use of MV in recipients of AHSCT and to identify predictors of survival in mechanically ventilated AHSCT patients. DESIGN: Retrospective, cohort analysis SETTING: Tertiary-care, university-affiliated medical center. PATIENTS: One hundred fifty-nine consecutive patients who underwent AHSCT. INTERVENTIONS: Patient surveillance and data collection. MEASUREMENTS AND RESULTS: The primary outcome measure was the need for MV, and the secondary end point was survival after MV. Of 159 patients, 17 required MV (10. 7%). Three variables were associated with the need for MV: increasing age, use of total body irradiation in the conditioning regimen, and treatment with amphotericin B. As a screening test to predict the need for MV, no risk factor had a sensitivity or specificity > 82%. Three of the 17 mechanically ventilated patients (17.6%) survived to discharge. Only the mean APACHE (acute physiology and chronic health evaluation) II score separated survivors from nonsurvivors (21.7 vs 31.4; p = 0.029). Both the duration of MV and the length of stay in the ICU were similar in survivors and nonsurvivors. CONCLUSIONS: We conclude that MV is infrequently needed following AHSCT. Although survival after MV in these patients is limited, clinical variables do not reliably allow clinicians to prospectively identify patients destined to die.

Delivery of high concentrations of inspired oxygen via Tusk mask.

OBJECTIVES: Nonrebreather face masks (NRM) are frequently used in patients with respiratory distress and profound hypoxemia. A simpler modification to the partial rebreather face mask, using only two pieces of respiratory tubing or "tusks," has also been shown to increase FiO2 compared with the NRM in five normal subjects. Clinically, we have observed this modification to further increase PaO2 in critically ill patients already using the NRM in the intensive care unit. This study was designed to compare the Tusk mask with the NRM in both a larger group of normal subjects and in patients with underlying lung disease. DESIGN: Prospective, randomized, crossover study. SETTING: A university teaching hospital and tertiary care referral center. SUBJECTS: Sixteen normal subjects (11 male and 5 female; age 30.4+/-6.8 [SD] yrs) and seven patients with interstitial lung disease (ILD) (3 male and 4 female; age 68.1+/-11.9 yrs). INTERVENTIONS: Subjects and patients served as their own controls and were randomized to wear either the NRM or Tusk mask for a 30-min period. After a 60-min washout period, the other mask was applied. MEASUREMENTS AND MAIN RESULTS: Arterial blood gas measurements were performed immediately before and at the end of each 30-min test period. Respiratory synchronization during the study period was achieved, using a metronome. In the normal subjects, PaO2 using the NRM and Tusk masks increased 290.0+/-57.1 torr (38.6+/-7.6 kPa) and 330.0+/-68.9 torr (44.0 +/-9.2 kPa), respectively (p=.032). PaO2 increased 293.4+/-38.0 torr (39.1+/-5.1 kPa) with the NRM and 378.4+/-61.7 torr (50.4+/-8.2 kPa) with the tusk mask (p=.001) in the patients with ILD. There was no statistically significant change seen in mean PaCO2 with either mask in either group. The mean PaO2 returned to within 6% of baseline in both groups after the washout period. CONCLUSIONS: Both normal subjects and patients with compromised pulmonary function achieved a higher PaO2 using a Tusk mask than when using the conventional NRM, at the same oxygen flow rate. Patients with hypoxemia may obtain lifesaving benefit from the additional concentration of oxygen delivered via the Tusk mask.

Diffuse tumor microembolism: a rare cause of a high-probability perfusion scan.

Pulmonary tumor embolism is a rare but well-documented cause of respiratory failure in patients with cancer. This entity is probably clinically underrecognized and may represent an important cause of morbidity and mortality. A typical pattern of multiple peripheral subsegmental defects on perfusion lung scanning has been described. We present a case of a unilateral near absence of perfusion in a 53-year-old woman who on autopsy was found to have diffuse tumor microembolism. As new chemotherapeutic agents are developed for the treatment of malignancies, an early diagnosis may become more important. A high-probability perfusion scan should not dissuade the clinician from pursuing further evaluation. Cytologic findings of pulmonary venous blood may be diagnostic.

Endoscopic management of a pineal and suprasellar germinoma with associated hydrocephalus: technical case report.

A patient with a synchronous pineal and suprasellar germinoma and symptomatic hydrocephalus underwent a minimally invasive endoscopic biopsy and third ventriculostomy. We performed multiple biopsies of both tumors and fenestration of the floor of the third ventricle with a flexible fiberoptic endoscope through a single burr hole. Postoperative quantitative cine-mode magnetic resonance imaging (MRI) confirmed the patency of the fenestration. Selected pineal/posterior third ventricle region tumors, especially radiosensitive germinomas, could be treated with this approach thereby obviating the need for either stereotactic or craniotomy/open biopsy and the subsequent placement of a permanent cerebrospinal fluid (CSF) shunt. The endoscopic approach to tumors in the pineal/posterior third ventricle region provides an accurate straightforward, and safe method of obtaining a diagnosis and treating the associated increased intracranial pressure.

Evaluation of internists' spirometric interpretations.

BACKGROUND: Correct interpretation of screening spirometry results is essential in making accurate clinical diagnoses and directing subsequent pulmonary evaluation. The general internist is largely responsible for interpreting screening spirometric tests at community hospitals. However, reports of new guidelines for screening spirometry are infrequently published in the general internal medicine literature. This can lead to incorrect interpretations. We sought to evaluate whether spirometric interpretations by a group of practicing general internists differed from those of two board-certified pulmonologists using guidelines published by the American Thoracic Society (ATS). METHODS: As part of a Continuous Quality Improvement project, all available screening spirometric tests over a 3-month period at two area community hospitals were reviewed. Only those performed on individuals age 18 or older were included in the analysis. Comparison was made between the interpretations of staff internists and those of two pulmonologists, who were blinded to the results of all other interpretations. We analyzed 110 screening spirometric tests from 84 males and 26 females. The patients ranged in age from 18 to 77 (mean 41 +/- 13 years of age). RESULTS: There was 97% concordance between the two pulmonologists' interpretations. In three cases, interpretations of only one pulmonologist agreed with those of the internists. The internists and both pulmonologists agreed in 73 cases. The majority of spirometric results in this subgroup were normal (n = 54). Both pulmonologists disagreed with internists' nomenclature in five cases. There was complete disagreement between the pulmonologists and the internists in the other 29 cases. Using the pulmonologists' interpretations as the "gold standard," the sensitivity (the internists' ability to correctly identify abnormal spirometric results) was 58.8% (95% confidence interval [CI] 42.2%, 73.3%), the specificity was 81.8% (95% CI 70.0%, 89.8%), the positive predictive value was 66.7% (95% CI 49.0%, 80.9%), and the negative predictive value was 76.1% (95% CI 64.3%, 85.0%). The most common inaccurate interpretations made by internists were "small airways disease" when spirometric results were normal (n = 8); "normal" when a restrictive pattern was present (n = 6), and "normal" when an abnormal flow-volume loop suggesting possible upper airway obstruction was present (n = 5). CONCLUSIONS: The spirometric interpretations of a group of general internists differed significantly from those of two board-certified pulmonologists using published guidelines in approximately one third of cases. This may be because subspecialty guidelines are infrequently published in the general internal medicine literature. We believe that wider dissemination of these interpretative guidelines and ongoing physician education would improve general internists' ability to identify patients who require further pulmonary evaluation.

Forest ecological classification and mapping: Their application for ecosystem management in Newfoundland.

A prerequisite to sustaining ecosystems is the inventory and classification of landscape structure and composition. Ecological classification and mapping involves the delineation of landscapes into easily recognizable units. Topography, soils, vegetation, physical landscape form, and successional pathways are delineation criteria commonly used.Damman (1967) developed a forest type classification system for Newfoundland using vegetation, soil and landforms as the defining criteria. Damman's forest types were used in combination with mensurational data to assign forest types to timber volume productivity classes. Since each of the Damman forest types is associated with characteristic soils, parent materials, moisture regime and topographic position, the mapping units are similar to Canada Land Inventory (CLI) mapping units. Field work to confirm the correlation between Damman forest types and CLI capability classes was initiated in 1993. CLI maps were recoded in 1994 and Damman forest types were determined; resulting ecosystem-based maps provide a common framework to assess forestry/wildlife interactions in an ecosystem planning process.

The preflight evaluation. A comparison of the hypoxia inhalation test with hypobaric exposure.

STUDY OBJECTIVES: We sought to compare arterial oxygen partial pressure (PaO2) relationships between a 15.1% hypoxia inhalation test (HIT) at sea level and a hypobaric chamber exposure equivalent to 2,438 m (8,000 feet) of altitude above sea level in patients with chronic obstructive pulmonary disease (COPD) and healthy subjects. DESIGN: Comparison of physiologic variables before and during intervention. SETTING: A referral-based pulmonary disease clinic at a US Army medical center in a metropolitan area. SUBJECTS: The study included three groups: group 1, 15 patients, 3 women and 12 men, with COPD (forced expiratory volume in the first second [FEV1, mean +/- SD], 41 +/- 14% of predicted); group 2, 9 healthy men; and group 3, 18 men with COPD (FEV1, 31 +/- 10% of predicted) previously reported in detail. INTERVENTIONS: We evaluated each group at sea level followed by one of two different types of hypoxic exposures. Group 1 received exposure to 15.1% oxygen at sea level, the HIT. Groups 2 and 3 received hypobaric chamber exposure equivalent to 2,438 m (8,000 feet) above sea level. MEASUREMENTS AND MAIN RESULTS: For all three groups combined, the arterial oxygen tension at sea level (PaO2SL) explained significant variability in PaO2 during hypoxic exposure according to the following formula: PaO2 during exposure = 0.417 (PaO2SL)] + 17.802 (n = 42; r = 0.756; p < 0.001). Neither the type of hypoxic exposure (HIT vs hypobaric), status as patient vs control, sex, nor age explained significant variability in PaO2 during hypoxia exposure after inclusion of PaO2SL as a covariate in analysis of variance. Subsequent analysis revealed that forced expiratory spirometric variables FEV1 and FEV1 to FVC ratio served as second order covariates with PaO2SL to improve description of PaO2 during hypoxia exposure for the combined samples (n = 42; p < 0.05). Analysis of residuals from regression analysis revealed approximately normal distribution. CONCLUSIONS: The PaO2 relationships did not differ between the 15.1% HIT at sea level and hypobaric exposures of 2,438 m (8,000 feet) above sea level. Normal subjects and patients with COPD formed a single relationship. The present study extends descriptive models to a larger range of subjects. Regression models have definable accuracy in predicting PaO2 during hypoxia exposure that increases with inclusion of spirometric variables.