BACKGROUND: Sinus barotraumas are a common condition in aviation medicine, sometimes compromising flight safety and even permanently grounding aircrew. Considering this and the ever-increasing amount of commercial aviation, a thorough examination is required.METHODS: In this survey study, an anonymous, electronic questionnaire was distributed to commercial aircrew of the three major commercial airlines operating in Finland (N = 3799), covering 93% of the target population (i.e., all commercial aircrew operating in Finland, N = 4083). Primary outcomes were self-reported prevalence, clinical characteristics, and health and occupational effects of sinus barotraumas in flight. Secondary outcomes were adjusted odds ratios (OR) for frequency of sinus barotraumas with respect to possible risk factors.RESULTS: Response rate was 47% (N = 1789/3799), with 61% (N = 1088) of the respondents having experienced sinus barotraumas in flight. Of those affected, 59% had used medications, 18% had undergone surgical procedures, and 53% had been on sick leave due to sinus barotraumas (38% during the last year) in flight. Factors associated with sinus barotraumas were female sex [OR, 2.47; 95% confidence interval (CI) 1.35–4.50] and a high number of upper respiratory tract infections (≥3 vs. <3 URTIs/yr: OR, 3.61; 95% CI 2.65–4.93).CONCLUSION: Sinus barotraumas were reported by 61% of commercial aircrew. They caused an increased need for medications, otorhinolaryngology-related surgical procedures, and sickness absence from flight duty. The possible risk factors were female sex and a high number of URTIs/yr.Lindfors OH, Ketola KS, Klockars TK, Leino TK, Sinkkonen ST. Sinus barotraumas in commercial aircrew. Aerosp Med Hum Perform. 2021; 92(11):857–863.

BACKGROUND: Transcutaneous measurement of carbon dioxide (CO₂) has been proposed for physiological monitoring of tactical jet aircrew because in some clinical settings it mirrors arterial CO₂ partial pressure (P_aco₂). End-tidal monitoring in laboratory settings is known to give high-fidelity estimates of P_aco₂.METHODS: The correspondence between end-tidal (P_ETco₂) and transcutaneous Pco₂ (tcPco₂) was examined in healthy volunteers under laboratory conditions of hyperoxia and hypoxia. Rest and exercise, skin heating and cooling, hyperventilation, and induced CO₂ retention were employed.RESULTS: Neither measure followed all known changes in P_aco₂ and tcPco₂ changed when the skin temperature near the probe changed. Bland-Altman analysis showed significant nonzero slopes under most conditions. Regression analysis indicated that oxygen partial pressure (Po₂) in tissue measured as transcutaneous Po₂ (tcPo₂) is an important explanatory variable for tcPco₂ in addition to P_ETco₂, and that local skin temperature also has an effect. Additionally, absorption atelectasis from breathing 100% O₂ may cause P_ETco₂ to deviate from P_aco₂.DISCUSSION: Even as a trend indicator for P_aco₂, tcPco₂ is not useful under conditions that resemble those in the highly dynamic tactical jet aircraft environment. P_ETco₂ is also not a good indicator of CO₂ status in pilots who breathe nearly 100% O₂.Shykoff BE, Lee LR, Gallo M, Griswold CA. Transcutaneous and end-tidal CO₂ measurements in hypoxia and hyperoxia. Aerosp Med Hum Perform. 2021; 92(11):864–872.

BACKGROUND: En route care (ERC) is a military aeromedical mission designed to transport a patient to a higher level of care. With the exception of one manual, there are no other formal Navy ERC guidelines, leaving the service to provide such missions ad hoc. Based on the authors’ review of available literature, it seems no prior research has been done on Navy rescue swimmers performing ERC, though many search and rescue (SAR) missions take place without designated medical personnel. This study specifically examines the type of provider involved in Navy ERC missions and the types of cases involved with the purpose of influencing Navy policy.METHODS: A cross-sectional study examining 829 air evacuations performed by Navy SAR flight crews from 2016 to 2019 was analyzed.RESULTS: Of 829 cases reviewed, patients were more likely to be active-duty personnel (51%) than civilian (47%), and there were 2.5 times more male than female patients. There were more trauma (54%) than medical (43%) patients, with Basic Life Support (BLS) level care (60%) delivered twice as often as Advanced Life Support (ALS) (28%). Search and Rescue Medical Technicians (SMTs) and rescue swimmers provided 83% of ERC, with rescue swimmers supporting 33% of all ERC missions alone.DISCUSSION: The results of this study are in contrast to previous ERC studies, in which rescue swimmer-only transports were excluded from the data. The results raise the question, do rescue swimmers need to be trained to a higher level of care?Henry SM, Stanfield MM. U.S. Navy aeromedical missions from 2016–2019 with a focus on en route care provider type. Aerosp Med Hum Perform. 2021; 92(11):873–879.

BACKGROUND: The speech recognition levels of cochlear implant (CI) users are still incompatible with ICAO hearing requirements for civil aviation pilots testing in the noisy background condition of the helicopter cockpit. In this study, we evaluated noise attenuation effects on speech recognition in the same background condition.METHODS: The study involved the evaluation of 12 Portuguese-speaking CI users with post-lingual deafness and with a pure tone average up to 35 dB HL between 500 and 2000 Hz and up to 50 dB at 3000 Hz on at least one of the ears, and of three normal hearing pilots (controls). We performed speech recognition tests using sentences, numbers, and disyllables for all participants through the VHF radio. The assessment took place inside a helicopter with engine on, using three setups: 1) with headset without the active noise cancellation; 2) activating the noise cancellation system of the headset itself; and 3) connecting the speech processor directly to the helicopter radio system.RESULTS: The headset active noise-cancellation improved only the recognition of sentences. The direct connection system compared to the headset without anti-noise attenuation significantly improved all the recognition tests. The median for numbers was 90%, but the best score for disyllables recognition was 56%.DISCUSSION: The noise attenuation resources proposed in this study improved the CI users’ speech recognition when exposed to the noisy helicopter cockpit. However, speech recognition of CI users still did not meet the standards of ICAO, which requires at least 80% for understanding disyllables in the speech in noise test.Caldeira JMA, Goffi-Gomez MVS, Imamura R, Bento RF. Noise attenuation effects on speech recognition of cochlear implant users inside helicopters. Aerosp Med Hum Perform. 2021; 92(11):880–885.

INTRODUCTION: Preflight body weight is a strong predictor of visual changes in spaceflight. To understand the effect of body weight on the eye, we examined the effect of increased body mass index on intraocular pressure on Earth.METHODS: We conducted a systematic review to summarize the relationship between weight parameters (including body mass index (BMI) and obesity indices), and intraocular pressure (IOP). Study selection and data extraction were performed in duplicate using EMBASE, MEDLINE, and CENTRAL, from database inception to the second week of April 2020.RESULTS: A total of 66 individual studies were included for qualitative analysis from the 1364 studies eligible for title and abstract screening. A total of 39 studies were available for quantitative analysis. The average BMI was 25.9 (range, 20.1–48.8) and the average IOP was 14.9 mmHg (range, 11.6–27.8). The overall pooled RR between BMI and elevated intraocular pressure (IOP) was 1.06 (95% CI, 1.04–1.07), meaning for each unit increase in BMI one is 6% more likely of having higher IOP than baseline. Two studies assessed the effects of bariatric surgery, and both showed significant decreases in IOP postoperatively.CONCLUSION: A higher BMI was associated with increased IOP in ground-based studies. IOP also decreased with weight loss. These data support the idea that alterations in body weight affect intraocular pressures. Further research is needed to understand the relationship between body weight, IOP, and microgravity-induced visual changes. This finding may also be useful clinically.Khan S, Kirubarajan A, Lee M, Pitha I, Buckey JC Jr. The correlation between body weight and intraocular pressure. Aerosp Med Hum Perform. 2021; 92(11):886–897.

BACKGROUND: While many COVID-19 studies focus on acute effects of the infection, few examine the intermediate and long-term sequelae of the illness. Studies have shown that a good portion of patients have chronic effects in several body systems for several months or longer. Such effects can potentially adversely impact pilot performance in flight. We sought to determine the long-term effects of COVID-19 infection, how such effects can affect pilot performance, and how to best evaluate pilots for aeromedical flight clearance.METHODS: We used the PubMed literature search engine to review peer-reviewed articles that focused on the intermediate and long-term effects of COVID-19 infection. Chronic signs and symptoms were subdivided based on the particular body organ system affected. Merging information obtained from case reviews, article reviews, and aeromedical standards, we created a risk stratification guide to assist with the aeromedical disposition of affected pilots.RESULTS: Long-term effects of COVID-19 infection can last for several months or longer. The most common effects are fatigue, weakness, pulmonary diffusion defects, depression, and anxiety.DISCUSSION: This review article focuses on the most common intermediate- and long-term COVID-19 conditions of aeromedical significance and the corresponding course of actions recommended for the aeromedical examiner. Aeromedical evaluation should take into consideration factors related to the pilot, aircraft type, and specific aviation environment. Such evaluation may include diagnostic testing, medical specialist consultation, preflight simulation in an altitude chamber, human centrifuge testing, and/or a flight simulator checkride.Ko SY, Nguyen NK, Lee CL, Lee LA, Nguyen KUT, Lee EC. Aeromedical implications of long-term COVID-19 sequelae. Aerosp Med Hum Perform. 2021; 92(11):898–907.

BACKGROUND: Normative performance (NP) describes the pilots’ adherence to tactics, techniques, and procedures (TTPs). Until now, there has not been a global NP measurement technique for beyond visual range (BVR) air combat, and the methodology and technology related to the evaluation of NP have fallen behind the pace of the overall technical progress of distributed mission operations (DMO) training.METHODS: Platform-independent core air combat tasks were identified. The execution of these tasks is directed with TTPs. BVR air combat missions were flown in a DMO simulator system and the design NP was varied between missions. Observers viewed debriefs of these missions and attempted to identify TTP-regulated air combat tasks. Once identified, they scored the pilots’ NP in those tasks. The scoring was based on the level of TTP adherence and the impact a nonadherence had on the mission accomplishment.RESULTS: All observers were able to identify most of the TTP-regulated air combat tasks. There was a strong positive correlation between the observed and design NP scores. The overall Kappa indicated a fair agreement between the observers. The percentage of observers’ NP assessments which agreed with the design NP varied from 49.60 to 85.28% in different air combat missions. On average, 73.96% of the observers’ NP scores agreed with the design NP scores.CONCLUSIONS: Observers were able to accurately identify TTP-regulated tasks and score NP of these tasks during an air combat debrief. There was a moderate agreement between the observers’ NP scores.Mansikka H, Virtanen K, Mäkinen L, Harris D. Normative performance measurement in simulated air combat. Aerosp Med Hum Perform. 2021; 92(11):908–912.

BACKGROUND: The aim of this retrospective registry study was to review the medical causes of RCAF pilot permanent grounding during the period 2008–2017 and to compare our findings to the previous study of 1978–1987 to determine if disease patterns had changed.METHODS: Material was obtained from the RCAF 1 Canadian Air Division Surgeon’s medical registry of military pilots. Anonymized data for permanently grounded pilots were classified by medical diagnosis, age, and training status.RESULTS: During the period 2008–2017, there were a total of 162 pilots permanently grounded, of which 110 were trained and 52 untrained.DISCUSSION: In comparison to the 1991 study, there has been a decrease in permanent groundings due cardiovascular disease, but an increase due to mental health conditions, musculoskeletal issues, and motion sickness.Haworth D, Gray G, Zoltenko R, Bashirzadeh AJ. Permanent medical grounding in Royal Canadian Air Force pilots (2008–2017). Aerosp Med Hum Perform. 2021; 92(11): 913–918.

BACKGROUND: Cryptogenic stroke leading to cerebellar infarction is a rare but serious cause of acute nausea and vomiting. This has the potential of devastating consequences if this occurs in aviators during flight. We present a case of cryptogenic stroke causing incapacitating nausea and vomiting in a U.S. Air Force pilot.CASE REPORT: A 36-yr-old active-duty U.S. Air Force male pilot developed acute onset severe vertigo, nausea, and vomiting during initial descent. Initial computed tomography imaging was normal and his initial assessment yielded a diagnosis of benign paroxysmal positional vertigo. MRI-Brain at 1 mo revealed a small right inferomedial cerebellar infarct. Echocardiography revealed a patent foramen ovale and bilateral atrial enlargement. He made a full neurological recovery and was eventually returned to active flight status with Flying Class IIC waiver.DISCUSSION: Cryptogenic stroke caused by patent foramen ovale (PFO) is uncommon. However, this is increased in patients younger than 50 yr of age. This can lead to an acute incapacitation with varying degrees of dysfunction. There is controversial discussion of treatment options for secondary stroke prevention with PFO. However, there is no significant literature on primary prevention in these patients. A small subset of patients benefit from closure of PFO and most patients benefit from antiplatelet therapy after a stroke occurs. There may also be a significant subset of patients with PFO that may benefit from antiplatelet therapy as a primary prevention of stroke.Lytle ME, Martin BR. Acute cerebellar stroke in a military active-duty pilot. Aerosp Med Hum Perform. 2021; 92(11): 919–923.