British Thoracic Society Standards of Care Committee. Managing passengers with respiratory disease planning air travel: British Thoracic Society recommendations

Retinal vascular reactivity in carriers of X-linked inherited retinal disease - a study using optical coherence tomography angiography

Purpose

Female carriers of X-linked inherited retinal diseases (IRDs) can show highly variable phenotypes and disease progression. Vascular reactivity, a potential disease biomarker, has not been investigated in female IRD carriers. In this study, functional optical coherence tomography angiography (OCT-A) was used to dynamically assess the retinal microvasculature of X-linked IRD carriers.

Methods

Genetically confirmed female carriers of IRDs (choroideremia or X-linked retinitis pigmentosa), and healthy women were recruited. Macular angiograms (3x3mm, Zeiss Plex Elite 9000) were obtained in 36 eyes of 15 X-linked IRD female carriers and 21 age-matched control women. Two tests were applied to test vascular reactivity: (i) mild hypoxia and (ii) handgrip test, to induce a vasodilatory or vasoconstrictive response, respectively. Changes to vessel density (VD) and vessel length density (VLD) were independently evaluated during each of the tests for both the superficial and deep capillary plexuses.

Results

In the control group, the superficial and deep VD decreased during the handgrip test (p<0.001 and p=0.037, respectively). Mean superficial VLD also decreased during the handgrip test (p=0.025), while the deep plexus did not change significantly (p=0.108). During hypoxia, VD and VLD increased in the deep plexus (p=0.027 and p=0.052, respectively) but not in the superficial plexus. In carriers, the physiologic vascular responses seen in controls were not observed in either plexus during either test, with no difference in VD or VLD noted (all p>0.05).

Conclusions

Functional OCT-A is a useful tool to assess dynamic retinal microvascular changes. Subclinical impairment of the physiological vascular responses seen in carriers of X-linked IRDs may serve as a valuable clinical biomarker.

Effects of moderate alcohol consumption and hypobaric hypoxia: implications for passengers' sleep, oxygen saturation and heart rate on long-haul flights

BACKGROUND

Passengers on long-haul flights frequently consume alcohol. Inflight sleep exacerbates the fall in blood oxygen saturation (SpO2) caused by the decreased oxygen partial pressure in the cabin. We investigated the combined influence of alcohol and hypobaric hypoxia on sleep, SpO2 and heart rate.

METHODS

Two groups of healthy individuals spent either two nights with a 4-hour sleep opportunity (00:00-04:00 hours) in the sleep laboratory (n=23; 53 m above sea level) or in the altitude chamber (n=17; 753 hPa corresponding to 2438 m above sea level, hypobaric condition). Participants consumed alcohol before one of the nights (mean±SE blood alcohol concentration 0.043±0.003%). The order of the nights was counterbalanced. Two 8-hour recovery nights (23:00-07:00 hours) were scheduled between conditions. Polysomnography, SpO2 and heart rate were recorded.

RESULTS

The combined exposure to alcohol and hypobaric condition decreased SpO2 to a median (25th/75th percentile) of 85.32% (82.86/85.93) and increased heart rate to a median (25th/75th percentile) of 87.73 bpm (85.89/93.86) during sleep compared with 88.07% (86.50/88.49) and 72.90 bpm (70.90/78.17), respectively, in the non-alcohol hypobaric condition, 94.97% (94.59/95.33) and 76.97 bpm (65.17/79.52), respectively, in the alcohol condition and 95.88% (95.72/96.36) and 63.74 bpm (55.55/70.98), respectively, in the non-alcohol condition of the sleep laboratory group (all p<0.0001). Under the combined exposure SpO2 was 201.18 min (188.08/214.42) below the clinical hypoxia threshold of 90% SpO2 compared with 173.28 min (133.25/199.03) in the hypobaric condition and 0 min (0/0) in both sleep laboratory conditions. Deep sleep (N3) was reduced to 46.50 min (39.00/57.00) under the combined exposure compared with both sleep laboratory conditions (alcohol: 84.00 min (62.25/92.75); non-alcohol: 67.50 min (58.50/87.75); both p<0.003).

CONCLUSIONS

The combination of alcohol and inflight hypobaric hypoxia reduced sleep quality, challenged the cardiovascular system and led to extended duration of hypoxaemia (SpO2 <90%).

Humanitarian Aeromedical Retrieval using a Long-Range Commercial Aircraft: A Field Report

This field report presents the planning and execution of a large-scale aeromedical refugee retrieval operation amid the on-going Russia-Ukraine crisis. The retrieval was coordinated by the Italian Department of Civil Protection and led by the Centrale Remota Operazioni Soccorso Sanitario (CROSS), a governmental facility overseeing medical assistance. An Airbus A320 was chosen for its capacity of 165 passengers, with one emergency stretcher maintaining maximum seating. The aircraft was equipped with an Advanced Life Support kit, and specific considerations for medical equipment compliance were made. Special cases, including patients with on-going chemotherapy and end-stage kidney disease, underwent fit-to-fly screening. The boarding process in Lublin, Poland involved triage and arrangements for passengers with gastroenteric symptoms. Notably, 22 passengers with recent episodes of illness were isolated. The successful operation, demonstrating the viability of evacuating vulnerable individuals via commercial airlines, underscores the importance of precise planning and coordination in crisis situations.

Retrospective analysis of referrals for hypoxic challenge testing in children born preterm

INTRODUCTION

Children with a history of bronchopulmonary dysplasia (BPD) may be at risk of hypoxaemia at altitude, such as during air travel. We have performed preflight hypoxic challenge testing (HCT) since 2006, incorporating British Thoracic Society (BTS) guidance since 2011, to determine which children may require oxygen during air travel.

AIMS

We aimed to compare the outcome of HCTs in children with a history of BPD who met the 2011 BTS criteria and those who did not and, in addition to this, to interrogate the data for factors that may predict the outcome of HCT in this population.

METHODS

We performed a retrospective analysis of data from HCTs of children with a history of BPD referred 2006-2020. Cases were excluded if the patient had a respiratory comorbidity, was still on oxygen therapy, if the test was a repeat or if the clinical record was incomplete. Descriptive and univariate analysis of the data was performed, and a binary logistic regression model was fitted.

RESULTS

There were 79 HCTs, of which 24/79 (30%) did not meet BTS 2011 guidelines referral criteria. The analysis showed a greater proportion of desaturation in the group that did not meet criteria: 46% vs 27% (no statistical significance). Baseline oxygen saturations were higher in those who did not require oxygen during HCT and this variable was significant when adjusted for confounders.

CONCLUSIONS

This study found that the current criteria for referral for preflight testing may incorrectly identify those most at risk and highlights the need for further investigation to ensure those most at risk are being assessed prior to air travel.

Retracted: Chest digital dynamic radiography to detect changes in human pulmonary perfusion in response to alveolar hypoxia

INTRODUCTION

Hypoxic pulmonary vasoconstriction optimises oxygenation in the lung by matching the local-blood perfusion to local-ventilation ratio upon exposure to alveolar hypoxia. It plays an important role in various pulmonary diseases, but few imaging evaluations of this phenomenon in humans. This study aimed to determine whether chest digital dynamic radiography could detect hypoxic pulmonary vasoconstriction as changes in pulmonary blood flow in healthy individuals.

METHODS

Five Asian men underwent chest digital dynamic radiography before and after 60 sec breath-holding at the maximal inspiratory level in upright and supine positions. Alveolar partial pressure of oxygen and atmospheric pressure were calculated using the blood gas test and digital dynamic radiography imaging, respectively. To evaluate the blood flow, the correlation rate of temporal change in each pixel value between the lung fields and left cardiac ventricles was analysed.

RESULTS

Sixty seconds of breath-holding caused a mean reduction of 26.7 ± 6.4 mmHg in alveolar partial pressure of oxygen. The mean correlation rate of blood flow in the whole lung was significantly lower after than before breath-holding (before, upright 51.5%, supine 52.2%; after, upright 45.5%, supine 46.1%; both P < 0.05). The correlation rate significantly differed before and after breath-holding in the lower lung fields (upright, 11.8% difference; supine, 10.7% difference; both P < 0.05). The mean radiation exposure of each scan was 0.98 ± 0.09 mGy. No complications occurred.

CONCLUSIONS

Chest digital dynamic radiography could detect the rapid decrease in pulmonary perfusion in response to alveolar hypoxia. It may suggest hypoxic pulmonary vasoconstriction in healthy individuals.

Transportation of patients under extracorporeal membrane oxygenation support on an airliner: Flying bridge to transplantation

BACKGROUND

A retrieval programme was developed in Martinique (French West Indies) to provide extracorporeal membrane oxygenation for patients in the Caribbean, where heart transplantation and ventricular assist devices are not available. In 2011, the Department of Cardiac Surgery at the University Hospital of Fort-de-France (Martinique) developed a transfer programme to Paris (France) on an airliner, to refer patients for whom extracorporeal membrane oxygenation was not weanable to heart transplantation or a ventricular assist device.

AIM

To report this unique experience of transportation of patients under extracorporeal membrane oxygenation support on an airliner from the French West Indies to Paris.

METHODS

This was an observational and retrospective study of all patients under extracorporeal membrane oxygenation support who were transferred from Martinique to the Pitié-Salpêtrière Hospital/Sorbonne University in Paris between September 2011 and September 2019. Transport characteristics, complications during repatriation, cost and clinical outcomes at 30days and 1year were reported.

RESULTS

Twenty-six patients were transferred on an airliner; the retrieval distance was 7260km, and the mean duration was 14hours. Only two patients developed complications (pulmonary oedema and leg ischaemia), and no patient died during the flight. Nine patients had a ventricular assist device implanted, and six patients were transplanted. Thirty-day survival was 65.4%, and 1-year survival was 38.5%.

CONCLUSIONS

Transport under extracorporeal membrane oxygenation support on an airliner is safe and efficient, with an acceptable cost. This programme allowed patients under extracorporeal membrane oxygenation support in a remote centre, without access to transplantation or a ventricular assist device, to be referred for these techniques in specialized centres. This experience strengthens the strategy of developing regional networks around specialized extracorporeal membrane oxygenation centres.

Canadian Association of Radiologists/Canadian Association of Interventional Radiologists/Canadian Society of Thoracic Radiology Guidelines on Thoracic Interventions

Thoracic interventions are frequently performed by radiologists, but guidelines on appropriateness criteria and technical considerations to ensure patient safety regarding such interventions is lacking. These guidelines, developed by the Canadian Association of Radiologists, Canadian Association of Interventional Radiologists and Canadian Society of Thoracic Radiology focus on the interventions commonly performed by thoracic radiologists. They provide evidence-based recommendations and expert consensus informed best practices for patient preparation; biopsies of the lung, mediastinum, pleura and chest wall; thoracentesis; pre-operative lung nodule localization; and potential complications and their management.

Cardiorespiratory Adaptation to Short-Term Exposure to Altitude vs. Normobaric Hypoxia in Patients with Pulmonary Hypertension

Prediction of adverse health effects at altitude or during air travel is relevant, particularly in pre-existing cardiopulmonary disease such as pulmonary arterial or chronic thromboembolic pulmonary hypertension (PAH/CTEPH, PH). A total of 21 stable PH-patients (64 ± 15 y, 10 female, 12/9 PAH/CTEPH) were examined by pulse oximetry, arterial blood gas analysis and echocardiography during exposure to normobaric hypoxia (NH) (FiO2 15% ≈ 2500 m simulated altitude, data partly published) at low altitude and, on a separate day, at hypobaric hypoxia (HH, 2500 m) within 20−30 min after arrival. We compared changes in blood oxygenation and estimated pulmonary artery pressure in lowlanders with PH during high altitude simulation testing (HAST, NH) with changes in response to HH. During NH, 4/21 desaturated to SpO2 < 85% corresponding to a positive HAST according to BTS-recommendations and 12 qualified for oxygen at altitude according to low SpO2 < 92% at baseline. At HH, 3/21 received oxygen due to safety criteria (SpO2 < 80% for >30 min), of which two were HAST-negative. During HH vs. NH, patients had a (mean ± SE) significantly lower PaCO2 4.4 ± 0.1 vs. 4.9 ± 0.1 kPa, mean difference (95% CI) −0.5 kPa (−0.7 to −0.3), PaO2 6.7 ± 0.2 vs. 8.1 ± 0.2 kPa, −1.3 kPa (−1.9 to −0.8) and higher tricuspid regurgitation pressure gradient 55 ± 4 vs. 45 ± 4 mmHg, 10 mmHg (3 to 17), all p < 0.05. No serious adverse events occurred. In patients with PH, short-term exposure to altitude of 2500 m induced more pronounced hypoxemia, hypocapnia and pulmonary hemodynamic changes compared to NH during HAST despite similar exposure times and PiO2. Therefore, the use of HAST to predict physiological changes at altitude remains questionable. (ClinicalTrials.gov: NCT03592927 and NCT03637153).

[Adaptation to altitude in respiratory diseases]

The frequency of high-altitude sojourns (for work, leisure, air travel or during car/train journeys) justifies the question of their tolerance, especially in people with pre-existing respiratory disease. Reduced barometric pressure and abrupt variations in temperature and inhaled air density may be responsible for modifications affecting the respiratory system and, in fine, oxygenation. These modifications may compromise altitude tolerance, further worsen respiratory dysfunction and render physical exercise more difficult. In obstructive lung disease, altitude is associated with gas exchange impairment, increased ventilation at rest and during exercise and heightened pulmonary artery pressure through hypoxic vasoconstriction, all of which may worsen dyspnea and increase the risk of altitude intolerance (acute mountain sickness, AMS). The most severe patients require rigorous evaluation, and hypoxic testing can be proposed. People with mild to moderate intermittent asthma can plan high altitude sojourns, provided that they remain under control at night and during exercise, and follow an adequate action plan in case of exacerbation. Respiratory disease patients with pulmonary artery hypertension (PAH) and chemoreflex control abnormalities need to be identified as at risk of altitude intolerance.

Sleep-Induced Hypoxia under Flight Conditions: Implications and Countermeasures for Long-Haul Flight Crews and Passengers

PURPOSE

Recuperation during sleep on board of commercial long-haul flights is a safety issue of utmost importance for flight crews working extended duty periods. We intended to explore how sleep and blood oxygenation (in wake versus sleep) are affected by the conditions in an airliner at cruising altitude.

METHODS

Healthy participants' sleep was compared between 4-h sleep opportunities in the sleep laboratory (n = 23; sleep lab, ie, 53 m above sea level) and in an altitude chamber (n = 20; flight level, ie, 753 hPa, corresponding to 2438 m above sea level). A subgroup of 12 participants underwent three additional conditions in the altitude chamber: 1) 4-h sleep at ground level, 2) 4-h sleep at flight level with oxygen partial pressure equivalent to ground level, 3) 4-h monitored wakefulness at flight level. Sleep structure and blood oxygenation were analysed with mixed ANOVAs.

RESULTS

Total sleep time at flight level compared to in the sleep laboratory was shorter (Δ mean ± standard error -11.1 ± 4.2 min) and included less N3 sleep (Δ -17.6 ± 5.4 min), while blood oxygenation was decreased. Participants spent 69.7% (± 8.3%) of the sleep period time but only 13.2% (± 3.0%) of monitored wakefulness in a hypoxic state (<90% oxygen saturation). Oxygen enrichment of the chamber prevented oxygen desaturation.

CONCLUSION

Sleep - but not wakefulness - under flight conditions induces hypobaric hypoxia which may contribute to impaired sleep. The results caution against the assumption of equivalent crew recovery in-flight and on the ground but hold promise for oxygen enrichment as a countermeasure. The present results have implications for flight safety and possible long-term consequences for health in crews.

Can Patients Travel by Air Less Than 1 Week After Lung Nodulectomy?

Objective: The study objective was to determine empirically based timing recommendations for safe air travel following lung nodulectomy. Methods: All patients who underwent pulmonary nonanatomic resection followed by air travel home immediately after discharge were identified at 2 institutions between 2014 and 2018. These patients were surveyed via telephone regarding any complications they may have experienced during their travel home and within the first week after discharge. These complications included shortness of breath, chest pain, drainage from their surgical sites, and evaluation by a health care provider in the interim, if they required. Results: Our study identified 27 patients who fit the inclusion criteria. The median number of days between surgery and flight home in the studied population was 4 days. The median number of days between chest tube removal and flight home was 2 days. None of the 27 patients reported experiencing shortness of breath, chest pain, drainage from their surgical sites, or need for evaluation by a health care provider within 1 week of discharge. Nine patients (33%) traveled by air with a small (<5%) pneumothorax documented on chest radiography after removal of thoracostomy tube. One (4%) patient successfully traveled without complication with a 10% pneumothorax. Conclusions: The findings of our study support the safety of air travel following lung nodulectomy in patients who have undergone uneventful wedge resection and have no significant pulmonary or cardiac comorbidities. It is not necessary for patients to wait the recommended 7 days prior to traveling.

Loss of consciousness during air travel: A case of lung bullae

A giant lung bulla occupies at least a third of the lung space. We present a middle-aged man who lost consciousness during an air flight for 30 minutes, without any respiratory symptoms. An incidental finding on chest x-ray revealed a giant bulla and a chest computed tomography imaging confirmed the diagnosis and ruled out a tension pneumothorax. A giant lung bulla is an uncommon cause of loss of consciousness and may be suspected if it occurs during air travel.

The secret enemy during a flight: Economy class syndrome

Deep venous thrombosis (DVT) and pulmonary thromboembolism (PTE) are the major causes of morbidity and mortality in immobile patients. There is observational evidence that intercontinental air travel is associated with a high incidence of DVT and PTE during or within 48 hours of long-distance flights. This situation is known as the economy class syndrome and can affect both the cabin crew and passengers. The term "economy class syndrome" refers to the occurrence of thrombotic events that mainly occur in passengers in the economy class of the aircraft during long-haul flights. This syndrome results from several factors related to the aircraft cabin and the passenger, acting together to predispose to excessive blood coagulation, which can result in venous thromboembolism. In this review, we have shared the relationship between air travel and the formation of DVT and PTE.

Aeromedical Transport of Critically Ill Patients: A Literature Review

The aeromedical transport of critically ill patients has become an integral part of practicing medicine on a global scale. The development of reliable portable medical equipment allows physicians, emergency medical technicians, and nurses to transport wounded and diseased patients under constant critical care attention. Air transportation involves utilizing a fixed-wing (airplane) or rotor-wing (helicopter) aircraft to accomplish different types of transports ranging from scene responses to international transfers. The proper preparation and management of patients undergoing aeromedical transport require a basic understanding of the physiological changes and unique challenges encountered within the aircraft environment at 8,000 ft above sea level. The purpose of this paper is to review the literature and provide guidelines for approaching the aeromedical transportation of critically ill patients.

Is there a doctor on the plane? A review of in-flight emergencies for the on-board radiologist

In-flight medical emergencies (IFME) are the acute on-service events involving illness or injury to a passenger with the potential for long-term health compromise. With the continuously rising number of flights available, both domestically and internationally, it is conceivable that the number of IFMEs will similarly continue to rise. Although most of these instances are relatively self-limited, the rare instance of a severe occurrence justifies preparation, both from in-flight staff and healthcare providers traveling on these flights. Given these events' sporadic nature and the variable availability of medical support, all physicians need to understand their in-flight ethical and legal capabilities, the available medical supplies, and the most likely etiologies to manage such situations successfully. Most radiologists rarely utilize the hands-on, clinical skills developed in medical school or internship for emergencies beyond allergic contrast reactions. Therefore, they may not be adept in caring for patients during an IFME. As such, we present a thorough overview and literature review for the radiologist regarding the management of various acute IFMEs, with consideration for ethical and legal precedence and a review of medical equipment available on-board.

[Heart Patients and Exposure to Altitude]

Overall, heart patients should be advised individually with respect to their tolerance of altitudes. However, the historical reflex that altitude 'per se' is bad for heart patients should become a thing of the past. Adequately treated and stable patients can usually go up to an altitude of 2500 m without any restrictions. Higher altitudes are also possible for a large number of patients, but may require an adaptation of the medication and further clarification. This is especially the case when physical work is to be performed at great heights.

Knowledge, confidence and attitude of primary care doctors in managing in-flight medical emergencies: a cross-sectional survey

INTRODUCTION

Medical emergencies occur at a rate of one in 604‒753 flights. Doctors travelling on commercial flights may encounter an in-flight medical emergency requiring their assistance. There is a paucity of studies on how confident primary care doctors are in managing in-flight medical emergencies. This study aimed to determine the knowledge, confidence and attitude of primary care doctors in managing in-flight medical emergencies.

METHODS

A cross-sectional study was conducted on all primary care doctors working in government health clinics in Kuala Lumpur, Malaysia, from October 2016 to November 2016. A self-reported questionnaire was used, which included questions on demographic information, knowledge of in-flight medicine, and the attitude and confidence of primary care doctors in managing in-flight medical emergencies.

RESULTS

182 doctors completed the questionnaire (92.9% response rate). The mean knowledge score was 8.9 out of a maximum score of 20. Only 11.5% of doctors felt confident managing in-flight medical emergencies. The majority (69.2%) would assist in an in-flight medical emergency, but the readiness to assist was reduced if someone else was already helping or if they were not familiar with the emergency. Total knowledge score was positively associated with confidence in managing in-flight medical emergencies (p = 0.03).

CONCLUSION

Only one in ten primary care doctors in this study felt confident managing in-flight medical emergencies. A higher total knowledge score of in-flight medical emergencies was positively associated with greater confidence in managing them. Educational programmes to address this gap in knowledge may be useful to improve doctors' confidence in managing in-flight medical emergencies.

Assessing Patients for Air Travel

Advising patients before air travel is a frequently overlooked, but important, role of the physician, particularly primary care providers and pulmonary specialists. Although physiologic changes occur in all individuals during air travel, those with underlying pulmonary disease are at increased risk of serious complications and require a specific approach to risk stratification. We discuss the available tools for assessment of preflight risk and strategies to minimize potential harm. We also present a case discussion to illustrate our approach to assessing patients for air travel and discuss the specific conditions that should prompt a more thorough preflight workup.

In-Flight Medical Emergencies: A Review

IMPORTANCE

In-flight medical emergencies (IMEs) are common and occur in a complex environment with limited medical resources. Health care personnel are often asked to assist affected passengers and the flight team, and many have limited experience in this environment.

OBSERVATIONS

In-flight medical emergencies are estimated to occur in approximately 1 per 604 flights, or 24 to 130 IMEs per 1 million passengers. These events happen in a unique environment, with airplane cabin pressurization equivalent to an altitude of 5000 to 8000 ft during flight, exposing patients to a low partial pressure of oxygen and low humidity. Minimum requirements for emergency medical kit equipment in the United States include an automated external defibrillator; equipment to obtain a basic assessment, hemorrhage control, and initiation of an intravenous line; and medications to treat basic conditions. Other countries have different minimum medical kit standards, and individual airlines have expanded the contents of their medical kit. The most common IMEs involve syncope or near-syncope (32.7%) and gastrointestinal (14.8%), respiratory (10.1%), and cardiovascular (7.0%) symptoms. Diversion of the aircraft from landing at the scheduled destination to a different airport because of a medical emergency occurs in an estimated 4.4% (95% CI, 4.3%-4.6%) of IMEs. Protections for medical volunteers who respond to IMEs in the United States include a Good Samaritan provision of the Aviation Medical Assistance Act and components of the Montreal Convention, although the duty to respond and legal protections vary across countries. Medical volunteers should identify their background and skills, perform an assessment, and report findings to ground-based medical support personnel through the flight crew. Ground-based recommendations ultimately guide interventions on board.

CONCLUSIONS AND RELEVANCE

In-flight medical emergencies most commonly involve near-syncope and gastrointestinal, respiratory, and cardiovascular symptoms. Health care professionals can assist during these emergencies as part of a collaborative team involving the flight crew and ground-based physicians.

Stress Oximetry: Description of a Test to Determine Readiness for Discontinuing Oxygen Therapy in Infants with Chronic Lung Disease

Background

In infants with CLD there are no objective tests to monitor an infant's progress towards weaning out of oxygen inhalation therapy (O₂IT). A test involving staged maneuvers of increasing respiratory stress while decreasing oxygen support, termed Stress Oximetry (StressOx), has been used at our center for weaning O₂IT.

Objective

To report the clinical utility of "StressOx" in evaluating readiness for discontinuing O₂IT in infants with CLD.

Methods

A retrospective review was done of StressOx tests administered at our center from 2002-2008. StressOx was performed based on a consistent clinical protocol in all eligible infants on O₂IT. O₂IT was generally discontinued after infant had passed two StressOx tests and subsequently infants were monitored for a minimum of 7 days to determine successful weaning.

Results

There were 279 infants with 899 tests that met inclusion criteria. An average of 3 tests per infant was done, one week apart. The test had a specificity of 97.4% and a positive predictive value of 99.6% in determining success of discontinuing O₂IT.

Conclusions

StressOx appears to be a clinically useful test that may help in determining an infant's ability to successfully wean out of O₂IT. Further validation of this test is warranted.

Should I stay or should I go? COPD and air travel

Chronic obstructive pulmonary disease (COPD) is a challenging respiratory problem throughout the world. Although survival is prolonged with new therapies and better management, the magnitude of the burden resulting from moderate-to-severe disease is increasing. One of the major aims of the disease management is to try to break the vicious cycle of patients being homebound and to promote an active lifestyle. A fundamental component of active daily life is, of course, travelling. Today, the world is getting smaller with the option of travelling by air. Air travel is usually the most preferred choice as it is easy, time saving, and relatively inexpensive. Although it is a safe choice for many passengers, the environment inside the aeroplane may sometimes have adverse effects on health. Hypobaric hypoxaemia due to cabin altitude may cause health risks in COPD patients who have limited cardiopulmonary reserve. Addressing the potential risks of air travel, promoting proactive strategies including pre-flight assessment, and education of COPD patients about the “fitness to fly” concept are essential. Thus, in this narrative review, we evaluated the current evidence for potential risks of air travel in COPD and tried to give a perspective for how to plan safe air travel for COPD patients.

COPD patients should be informed about the “fitness to fly” concept and patients with moderate-to-severe disease need to be assessed with clinical and functional parameters for possible risk factors for in-flight hypoxaemia before flyinghttp://ow.ly/Yd4A30k41Hq

Hypoxia challenge test and retinal circulation changes - a study using ocular coherence tomography angiography

PURPOSE

Previous studies report that the response of retinal vessels to a decrease in oxygen (hypoxia) is vasodilation, thus increasing blood flow. We aimed to characterize the changes in retinal microvasculature induced by a mild hypoxia stress test in a healthy population, using ocular coherence tomography angiography (OCT-A) technology.

METHODS

Interventional repeated-measures study. The standardized hypoxia challenge test (HCT) was performed to all volunteers, according to the British Thoracic Society protocol. Ocular coherence tomography angiography (OCT-A) was performed at three time-points (baseline, during HCT and 30' posthypoxia). Macular and peripapillary vessel densities were assessed using the built-in software. To minimize bias, analysis was performed separately in right (OD) and left (OS) eyes. Repeated-measures anova and mean comparison analysis were used as statistical tests (stata v13).

RESULTS

Studied population included 30 healthy subjects (14 women), with a mean age of 28.8 ± 4.2 [range 22-37] years. Baseline vessel density increased in hypoxic conditions and subsequently decreased to near-baseline values in posthypoxia conditions. This pattern was observed for both eyes in both parafovea (OD: 55.3 ± 2.3 to 56.7 ± 1.9 to 55.8 ± 1.9, p < 0.05; OS: 56.9 ± 2.1 to 57.9 ± 1.9 to 57.3 ± 1.7, p < 0.05) and peripapillary (OD: 60.5 ± 0.5 to 62.6 ± 0.5 to 60.1 ± 0.4, p < 0.05; OS: 60.4 ± 0.4 to 62.3 ± 0.5 to 60.7 ± 0.4, p < 0.05) areas.

CONCLUSION

To our knowledge, there are no published data specifically addressing mild hypoxia conditions and retinal microvasculature changes, using OCT-A. This pilot study may pave way to better understand vascular responses in disease setting.

Accurate diagnosis of latent tuberculosis in children, people who are immunocompromised or at risk from immunosuppression and recent arrivals from countries with a high incidence of tuberculosis: systematic review and economic evaluation

BACKGROUND

Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB) [(Zopf 1883) Lehmann and Neumann 1896], is a major cause of morbidity and mortality. Nearly one-third of the world's population is infected with MTB; TB has an annual incidence of 9 million new cases and each year causes 2 million deaths worldwide.

OBJECTIVES

To investigate the clinical effectiveness and cost-effectiveness of screening tests [interferon-gamma release assays (IGRAs) and tuberculin skin tests (TSTs)] in latent tuberculosis infection (LTBI) diagnosis to support National Institute for Health and Care Excellence (NICE) guideline development for three population groups: children, immunocompromised people and those who have recently arrived in the UK from high-incidence countries. All of these groups are at higher risk of progression from LTBI to active TB.

DATA SOURCES

Electronic databases including MEDLINE, EMBASE, The Cochrane Library and Current Controlled Trials were searched from December 2009 up to December 2014.

REVIEW METHODS

English-language studies evaluating the comparative effectiveness of commercially available tests used for identifying LTBI in children, immunocompromised people and recent arrivals to the UK were eligible. Interventions were IGRAs [QuantiFERON(®)-TB Gold (QFT-G), QuantiFERON(®)-TB Gold-In-Tube (QFT-GIT) (Cellestis/Qiagen, Carnegie, VA, Australia) and T-SPOT.TB (Oxford Immunotec, Abingdon, UK)]. The comparator was TST 5 mm or 10 mm alone or with an IGRA. Two independent reviewers screened all identified records and undertook a quality assessment and data synthesis. A de novo model, structured in two stages, was developed to compare the cost-effectiveness of diagnostic strategies.

RESULTS

In total, 6687 records were screened, of which 53 unique studies were included (a further 37 studies were identified from a previous NICE guideline). The majority of the included studies compared the strength of association for the QFT-GIT/G IGRA with the TST (5 mm or 10 mm) in relation to the incidence of active TB or previous TB exposure. Ten studies reported evidence on decision-analytic models to determine the cost-effectiveness of IGRAs compared with the TST for LTBI diagnosis. In children, TST (≥ 5 mm) negative followed by QFT-GIT was the most cost-effective strategy, with an incremental cost-effectiveness ratio (ICER) of £18,900 per quality-adjusted life-year (QALY) gained. In immunocompromised people, QFT-GIT negative followed by the TST (≥ 5 mm) was the most cost-effective strategy, with an ICER of approximately £18,700 per QALY gained. In those recently arrived from high TB incidence countries, the TST (≥ 5 mm) alone was less costly and more effective than TST (≥ 5 mm) positive followed by QFT-GIT or T-SPOT.TB or QFT-GIT alone.

LIMITATIONS

The limitations and scarcity of the evidence, variation in the exposure-based definitions of LTBI and heterogeneity in IGRA performance relative to TST limit the applicability of the review findings.

CONCLUSIONS

Given the current evidence, TST (≥ 5 mm) negative followed by QFT-GIT for children, QFT-GIT negative followed by TST (≥ 5 mm) for the immunocompromised population and TST (≥ 5 mm) for recent arrivals were the most cost-effective strategies for diagnosing LTBI that progresses to active TB. These results should be interpreted with caution given the limitations identified. The evidence available is limited and more high-quality research in this area is needed including studies on the inconsistent performance of tests in high-compared with low-incidence TB settings; the prospective assessment of progression to active TB for those at high risk; the relative benefits of two-compared with one-step testing with different tests; and improved classification of people at high and low risk for LTBI.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014009033.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Travel with CPAP machines: how frequent and what are the problems?

BACKGROUND

Obstructive sleep apnoea syndrome is a common condition for which continuous positive airways pressure (CPAP) is the standard treatment. The condition affects a population of which a substantial proportion will be travelling.

METHODS

We use a questionnaire survey of CPAP users to gain understanding regarding the behaviours, attitudes and problems surrounding travel with CPAP machines during travel and while abroad. All CPAP patients on our database at a UK district general hospital reviewed over a period of 4 years were sent a postal questionnaire.

RESULTS

A response rate of 53% was achieved giving data on 588 trips. In the last 2 years, 63.7% of respondents had travelled; reasons for not travelling were CPAP related in only five cases. Travellers took their CPAP machines on 81% of trips. A similar proportion of patients took their CPAP machines regardless of the mode of travel, destination or length of holiday. Problems with checking in the CPAP machine were encountered in 4% of trips, all as part of air travel. Just over a third of patients faced problems either with the power cord, adapter or transport of the CPAP machine. Of those taking overnight flights, half did not sleep and none used their CPAP machines in flight. CPAP usage while away did not differ to usage at home.

CONCLUSIONS

This is the first report to describe in some detail CPAP machine use and associated problems in travel and while away. The data may aid the targeting of brief interventions in CPAP clinics as well as helping to standardize the process of check-in in order to help travellers with CPAP machines.

Case Report of a Hypobaric Chamber Fitness to Fly Test in a Child With Severe Cystic Lung Disease

Patients with severe cystic lung disease are considered to be at risk for cyst rupture during air travel because of the possibility of increase in cyst size and impaired equilibration of pressure between the cysts and other parts of the lung. This may have clinically devastating consequences for the patient but may also result in significant costs for emergency alteration of flight schedule. We report the use of a hypobaric chamber to simulate cabin pressure changes encountered on a commercial flight to assess the safety to fly of a child with severe cystic lung disease secondary to Langerhans cell histiocytosis. The test did not result in an air leak, and the child subsequently undertook air travel without mishap. This is the first reported use of a hypobaric chamber test in a child with severe cystic lung disease. This test has the potential to be used as a fitness to fly test in children at risk for air leak syndromes who are being considered for air travel.

Pre-flight evaluation of adult patients with cystic fibrosis: a cross-sectional study

BACKGROUND

Air travel may imply a health hazard for patients with cystic fibrosis (CF) due to hypobaric environment in the aircraft cabin. The objective was to identify pre-flight variables, which might predict severe hypoxaemia in adult CF patients during air travel.

METHODS

Thirty adult CF-patients underwent pre-flight evaluation with spirometry, arterial oxygen tension (PaO₂), pulse oximetry (SpO₂) and cardiopulmonary exercise testing (CPET) at sea level (SL). The results were related to the PaO₂ obtained during a hypoxia-altitude simulation test (HAST) in which a cabin altitude of 2438 m (8000 ft) was simulated by breathing 15.1% oxygen.

RESULTS

Four patients fulfilled the criteria for supplemental oxygen during air travel (PaO_{2 HAST} < 6.6 kPa). While walking slowly during HAST, another eleven patients dropped below PaO_{2 HAST} 6.6 kPa. Variables obtained during CPET (PaO_{2 CPET}, SpO_{2 CPET}, minute ventilation/carbon dioxide output, maximal oxygen uptake) showed the strongest correlation to PaO_{2 HAST}.

CONCLUSIONS

Exercise testing might be of value for predicting in-flight hypoxaemia and thus the need for supplemental oxygen during air travel in CF patients. Trial registration The study is retrospectively listed in the ClinicalTrials.gov Protocol Registration System: NCT01569880 (date; 30/3/2012).

Hypoxia Challenge Testing in Neonates for Fitness to Fly

BACKGROUND

Preflight hypoxia challenge testing (HCT) in a body plethysmograph has previously been done only on infants >3 months of corrected gestational age (CGA). This study aims to determine the earliest fit-to-fly age by testing neonates <1 week old.

METHODS

A prospective observational study was carried out on 3 groups of infants: healthy term infants ≤7 days old, preterm infants (≥34 weeks CGA) 2 to 3 days before discharge, and preterm infants with bronchopulmonary dysplasia (BPD). HCT was conducted using a body plethysmograph with a 15% fraction of inspired oxygen. The oxygen saturation (Spo2) test fail point was <85%.

RESULTS

Twenty-four term (mean CGA 40 weeks), 62 preterm (37 weeks), and 23 preterm with BPD (39.5 weeks) infants were tested. One term infant (4.2%) and 12 preterm infants without BPD (19.4%) failed. Sixteen (69.3%) preterm infants with BPD failed (P < .001), with a median drop in Spo2 of 16%. At 39 weeks CGA, neither preterm infants without BPD nor term infants had an Spo2 <85%. However, 7 of 12 term infants with BPD failed the HCT.

CONCLUSIONS

Term and preterm infants without BPD born at >39 weeks CGA do not appear to be likely to desaturate during a preflight HCT and so can be deemed fit to fly according to current British Thoracic Society Guidelines.

Primary spontaneous pneumothorax presenting to a chiropractic clinic as undifferentiated thoracic spine pain: a case report

OBJECTIVE

To present a case of primary spontaneous pneumothorax presenting to a chiropractic clinic as undifferentiated thoracic spine pain.

CLINICAL FEATURES

A tall thin 25-year-old male anxiously presented to a chiropractic clinic with six days of sudden unexplained left thorax pain. His breathing was laboured and his dry cough aggravating. After assessment a high clinical suspicion of primary spontaneous pneumothorax prevailed.

INTERVENTION AND OUTCOME

The patient was referred to hospital for further investigation and primary spontaneous pneumothorax was confirmed on chest radiograph. He underwent immediate tube thoracostomy to drain the air from his pleural space and to re-inflate his lung. After three days the tube was removed. By two weeks the lung had returned to full size. No recurrences have occurred to date.

CONCLUSIONS

Primary spontaneous pneumothorax is a medical emergency in the presence of shortness of breath. The focus of treatment is to drain air from the pleural linings and to prevent recurrences. In less severe cases, patients may believe they have thoracic spine pain and seek manual therapy care. This case highlights the important role chiropractors have as primary contact health care providers.

Prematurity and respiratory outcomes program (PROP): study protocol of a prospective multicenter study of respiratory outcomes of preterm infants in the United States

Background

With improved survival rates, short- and long-term respiratory complications of premature birth are increasing, adding significantly to financial and health burdens in the United States. In response, in May 2010, the National Institutes of Health (NIH) and the National Heart, Lung, and Blood Institute (NHLBI) funded a 5-year $18.5 million research initiative to ultimately improve strategies for managing the respiratory complications of preterm and low birth weight infants. Using a collaborative, multi-disciplinary structure, the resulting Prematurity and Respiratory Outcomes Program (PROP) seeks to understand factors that correlate with future risk for respiratory morbidity.

Methods/Design

The PROP is an observational prospective cohort study performed by a consortium of six clinical centers (incorporating tertiary neonatal intensive care units [NICU] at 13 sites) and a data-coordinating center working in collaboration with the NHLBI. Each clinical center contributes subjects to the study, enrolling infants with gestational ages 23 0/7 to 28 6/7 weeks with an anticipated target of 750 survivors at 36 weeks post-menstrual age. In addition, each center brings specific areas of scientific focus to the Program. The primary study hypothesis is that in survivors of extreme prematurity specific biologic, physiologic and clinical data predicts respiratory morbidity between discharge and 1 year corrected age. Analytic statistical methodology includes model-based and non-model-based analyses, descriptive analyses and generalized linear mixed models.

Discussion

PROP incorporates aspects of NICU care to develop objective biomarkers and outcome measures of respiratory morbidity in the <29 week gestation population beyond just the NICU hospitalization, thereby leading to novel understanding of the nature and natural history of neonatal lung disease and of potential mechanistic and therapeutic targets in at-risk subjects.

Trial registration

Clinical Trials.gov NCT01435187.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-015-0346-3) contains supplementary material, which is available to authorized users.

Management of lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM), a multisystem disease affecting almost exclusively women, is characterized by cystic lung destruction and presents with dyspnea, recurrent pneumothoraxes, chylous effusions, lymphangioleiomyomas, and angiomyolipomas. It is caused by the proliferation of a cancer-like LAM cell that possesses a mutation in either the tuberous sclerosis complex (TSC)1 or TSC2 genes. This article reviews current therapies and new potential treatments that are currently undergoing investigation. The major development in the treatment of LAM is the discovery of two mammalian target of rapamycin (mTOR) inhibitors, sirolimus and everolimus, as effective drugs. However, inhibition of mTOR increases autophagy, which may lead to enhanced LAM cell survival. Use of autophagy inhibitors, for example, hydroxychloroquine, in combination with sirolimus is now the subject of an ongoing drug trial (SAIL trial). Another consequence of mTOR inhibition by sirolimus is an increase in Rho activity, resulting in reduced programmed cell death. From these data, the concept evolved that a combination of sirolimus with disruption of Rho activity with statins (e.g. simvastatin) may increase TSC-null cell death and reduce LAM cell survival. A combined trial of sirolimus with simvastatin is under investigation (SOS trial). Since LAM occurs primarily in women and TSC-null cell survival and tumor growth is promoted by estrogens, the inhibition of aromatase to block estrogen synthesis is currently undergoing study (TRAIL trial). Other targets, for example, estrogen receptors, mitogen-activated protein kinase inhibitors, vascular endothelial growth factor-D signaling pathway, and Src kinase, are also being studied in experimental model systems. As in the case of cancer, combination therapy may become the treatment of choice for LAM.

Cleared for takeoff: The effects of hypobaric conditions on traumatic pneumothoraces

BACKGROUND

Current guidelines suggest that traumatic pneumothorax (tPTX) is a contraindication to commercial airline travel, and patients should wait at least 2 weeks after radiographic resolution of tPTX to fly. This recommendation is not based on prospective, physiologic study. We hypothesized that despite having a radiographic increase in pneumothorax size while at simulated altitude, patients with a recently treated tPTX would not exhibit any adverse physiologic changes and would not report any symptoms of cardiorespiratory compromise.

METHODS

This is a prospective, observational study of 20 patients (10 in Phase 1, 10 in Phase 2) with tPTX that has been treated by chest tube (CT) or high flow oxygen therapy. CT must have been removed within 48 hours of entering the study. Subjects were exposed to 2 hours of hypobaria (554 mm Hg in Phase 1, 471 mm Hg in Phase 2) in a chamber in Salt Lake City, Utah. Vital signs and subjective symptoms were recorded during the "flight." After 2 hours, while still at simulated altitude, a portable chest radiograph (CXR) was obtained. tPTX sizes on preflight, inflight, and postflight CXR were compared.

RESULTS

Sixteen subjects (80%) were male. Mean (SD) age and ISS were 49 (5) years and 10.5 (4.6), respectively. Fourteen (70%) had a CT to treat tPTX, which had been removed 19 hours (range, 4-43 hours) before the study. No subject complained of any cardiorespiratory symptoms while at altitude. Radiographic increase in tPTX size at altitude was 5.6 (0.61) mm from preflight CXR. No subject developed a tension tPTX. No subject required procedural intervention during the flight. Four hours after the study, all tPTX had returned to baseline size.

CONCLUSION

Patients with recently treated tPTX have a small increase in the size of tPTX when subjected to simulated altitude. This is clinically well tolerated. Current prohibitions regarding air travel following traumatic tPTX should be reconsidered and further studied.

LEVEL OF EVIDENCE

Therapeutic study, level IV.

Saudi Guidelines on the Diagnosis and Treatment of Pulmonary Hypertension: General management for pulmonary hypertension

Treatment of pulmonary hypertension (PH) patients is challenging and should only be initiated after a comprehensive diagnostic evaluation. Such treatment should ideally be done in specialized centers with full capability for hemodynamic measurements, having access to a broad range of PAH therapies, and adequate experience in the management of critically ill patients. The following discussion is intended to review the general measures and the non-specific (supportive) therapy used in managing PH patients, while the specific therapy will be discussed in a subsequent different article.

Air travel and pneumothorax

The number of medical emergencies onboard aircraft is increasing as commercial air traffic increases and the general population ages, becomes more mobile, and includes individuals with serious medical conditions. Travelers with respiratory diseases are at particular risk for in-flight events because exposure to lower atmospheric pressure in a pressurized cabin at cruising altitude may result in not only hypoxemia but also pneumothorax due to gas expansion within enclosed pulmonary parenchymal spaces based on Boyle's law. Risks of pneumothorax during air travel pertain particularly to those patients with cystic lung diseases, recent pneumothorax or thoracic surgery, and chronic pneumothorax. Currently available guidelines are admittedly based on sparse data and include recommendations to delay air travel for 1 to 3 weeks after thoracic surgery or resolution of the pneumothorax. One of these guidelines declares existing pneumothorax to be an absolute contraindication to air travel although there are reports of uneventful air travel for those with chronic stable pneumothorax. In this article, we review the available data regarding pneumothorax and air travel that consist mostly of case reports and retrospective surveys. There is clearly a need for additional data that will inform decisions regarding air travel for patients at risk for pneumothorax, including those with recent thoracic surgery and transthoracic needle biopsy.

High altitude journeys and flights are associated with an increased risk of flares in inflammatory bowel disease patients

BACKGROUND AND AIMS

Hypoxia can induce inflammation in the gastrointestinal tract. However, the impact of hypoxia on the course of inflammatory bowel disease (IBD) is poorly understood. We aimed to evaluate whether flights and/or journeys to regions lying at an altitude of >2000 m above the sea level are associated with flare-ups within 4 weeks of the trip.

METHODS

IBD patients with at least one flare-up during a 12-month observation period were compared to a group of patients in remission. Both groups completed a questionnaire.

RESULTS

A total of 103 IBD patients were included (43 with Crohn's disease (CD): mean age 39.3 ± 14.6 years; 60 with ulcerative colitis (UC): mean age 40.4 ± 15.1 years). Fifty-two patients with flare-ups were matched to 51 patients in remission. IBD patients experiencing flare-ups had more frequently undertaken flights and/or journeys to regions >2000 m above sea level within four weeks of the flare-up when compared to patients in remission (21/52 [40.4%] vs. 8/51 [15.7%], p=0.005).

CONCLUSIONS

Journeys to high altitude regions and/or flights are a risk factor for IBD flare-ups occurring within 4 weeks of travel.

Managing patients with stable respiratory disease planning air travel: a primary care summary of the British Thoracic Society recommendations

Air travel poses medical challenges to passengers with respiratory disease, principally because of exposure to a hypobaric environment. In 2002 the British Thoracic Society published recommendations for adults and children with respiratory disease planning air travel, with a web update in 2004. New full recommendations and a summary were published in 2011, containing key recommendations for the assessment of high-risk patients and identification of those likely to require in-flight supplemental oxygen. This paper highlights the aspects of particular relevance to primary care practitioners with the following key points: (1) At cabin altitudes of 8000 feet (the usual upper limit of in-flight cabin pressure, equivalent to 0.75 atmospheres) the partial pressure of oxygen falls to the equivalent of breathing 15.1% oxygen at sea level. Arterial oxygen tension falls in all passengers; in patients with respiratory disease, altitude may worsen preexisting hypoxaemia. (2) Altitude exposure also influences the volume of any air in cavities, where pressure x volume remain constant (Boyle's law), so that a pneumothorax or closed lung bulla will expand and may cause respiratory distress. Similarly, barotrauma may affect the middle ear or sinuses if these cavities fail to equilibrate. (3) Patients with respiratory disease require clinical assessment and advice before air travel to: (a) optimise usual care; (b) consider contraindications to travel and possible need for in-flight oxygen; (c) consider the need for secondary care referral for further assessment; (d) discuss the risk of venous thromboembolism; and (e) discuss forward planning for the journey.

Small bowel obstruction secondary to transport aircraft: coincidence or reality?

Small bowel obstructions (SBO) are a leading cause of admission to general surgery, posing the problem of the aetiology and treatment based on the diagnosis. More than 300 patients were admitted for SBO in 2011 in our institution. In our clinical practice, we have had to care for patients with SBO immediately after air travel, all of whom had an antecedent of abdominal surgery by laparotomy. The finding of episodes of acute SBO immediately following a commercial flight has never been reported in the literature. We report the cases of four patients for whom we offer several pathophysiological hypotheses, and we publish the first dietary rules for people with a history of intraperitoneal surgery to adopt during a flight.

Effects of commercial air travel on patients with pulmonary hypertension air travel and pulmonary hypertension

BACKGROUND

Limited data are available on the effects of air travel in patients with pulmonary hypertension (PH), despite their risk of physiologic compromise. We sought to quantify the incidence and severity of hypoxemia experienced by people with PH during commercial air travel.

METHODS

We recruited 34 participants for a prospective observational study during which cabin pressure, oxygen saturation (Sp O 2 ), heart rate, and symptoms were documented serially at multiple predefined time points throughout commercial flights. Oxygen desaturation was defined as SpO2, <85%.

RESULTS

Median flight duration was 3.6 h (range, 1.0-7.3 h). Mean ± SD cabin pressure at cruising altitude was equivalent to the pressure 1,968 ± 371 m (6,456 ± 1,218 ft) above sea level (ASL)(maximum altitude 5 2,621 m [8,600 ft] ASL). Median change in Sp O 2 from sea level to cruising altitude was 2 4.9% (range, 2.0% to 2 15.8%). Nine subjects (26% [95% CI, 12%-38%]) experienced oxygen desaturation during flight (minimum Sp O 2 5 74%). Thirteen subjects (38%) reported symptoms during flight, of whom five also experienced desaturations. Oxygen desaturation was associated with cabin pressures equivalent to . 1,829 m (6,000 ft) ASL, ambulation, and flight duration(all P values , .05).

CONCLUSIONS

Hypoxemia is common among people with PH traveling by air, occurring in one in four people studied. Hypoxemia was associated with lower cabin pressures, ambulation during flight, and longer flight duration. Patients with PH who will be traveling on flights of longer duration or who have a history of oxygen use, including nocturnal use only, should be evaluated for supplemental in-flight oxygen.

Commercial aircraft repatriation of patients with pneumothorax

The transfer of patients with a pneumothorax via a commercial airline involves many medical, aeronautic, and regulatory considerations. In an attempt to further investigate these issues, we reviewed the medical records of 32 patient cases with a pneumothorax who were repatriated on commercial aircrafts. Sixteen patients were transferred with the thoracostomy tube in place and were escorted by medical personnel at an average of 5 days (interquartile range [IQR], 4-7 days) from diagnosis. Five patients without initial intercostal drainage (who either showed very limited air collection or underwent immediate surgical treatment) were all escorted by a physician at an average of 24 days (IQR, 18-25 days) of diagnosis. Eleven patients were transferred without medical escort aboard a commercial flight after removal of the chest tube at an average of 15 days (IQR, 9-17 days) of the diagnosis. This case review suggests that physicians recommend and follow markedly different management plans for the patient with a pneumothorax who is being transferred nonurgently by a commercial airliner. This differing practice management also is noted in the various existing specialty and industry guidelines, which are not evidence based; our review shows that poor agreement exists not only in these various guidelines but also among medical practitioners.