High altitudes and partial pressure of arterial oxygen in patients with chronic obstructive pulmonary disease - A systematic review and meta-analysis.

IMPORTANCE: Prior study in healthy subjects has shown a reduction of partial pressure of arterial oxygen (PaO2) by -1.60 kPa/kilometre of altitude gain. However, the association of altitude-related change in PaO2 and altitude-related adverse health effects (ARAHE) in patients with chronic obstructive pulmonary disease (COPD) remain unknown. OBJECTIVE: To provide an effect size estimate for the decline in PaO2 with each kilometre of altitude gain and to identify ARAHE in relation to altitude in patients with COPD. www.crd.york.ac.uk/prospero: CRD42020217938. DATA SOURCES: A systematic search of PubMed and Embase was performed from inception to May 30, 2023. STUDY SELECTION: Peer-reviewed and prospective studies in patients with COPD staying at altitudes >1500 m providing arterial blood gases within the first 3 days at the target altitude. DATA EXTRACTION AND SYNTHESIS: Aggregate data (AD) on study characteristics were extracted, and individual patient data (IPD) were requested. Estimates were pooled using random-effects meta-analysis. MAIN OUTCOME AND MEASURES: Relative risk estimates and 95 % confidence intervals for the association between PaO2 and altitude in patients with COPD. RESULTS: Thirteen studies were included in the AD analysis, of which 6 studies (222 patients, 45.2 % female) provided IPD, thus were included in the quantitative analysis. The estimated effect size of PaO2 was -0.84 kPa [95 %CI, -0.92 to -0.76] per 1000 m of altitude gain (I2=65.0 %, P < 0.001). In multivariable regression analysis, COPD severity, baseline PaO2, age and time spent at altitude were predictors for PaO2 at altitude. Overall, 37.8 % of COPD patients experienced an ARAHE, whereas older age, female sex, COPD severity, baseline PaO2, and target altitude were predictors for the occurrence of ARAHE (area under ROC curve: 0.9275, P < 0.001). CONCLUSIONS AND RELEVANCE: This meta-analysis, providing altitude-related decrease in PaO2 and risk of ARAHE in patients with COPD ascending to altitudes >1500 m, revealed a lower altitude-related decrease in PaO2 in COPD patients compared with healthy. However, these findings might improve patient care and facilitate decisions about initiating preventive measures against hypoxaemia and ARAHE in patients with COPD planning an altitude sojourn or intercontinental flight, i.e. supplemental oxygen or acetazolamide.

THz optical beat-note detection with a fast superconducting hot electron bolometer operating up to 31†GHz.

We study the performance of a hot-electron bolometer (HEB) operating at THz frequencies based on superconducting niobium nitride films. We report on the voltage response of the detector over a large electrical detection bandwidth carried out with different THz sources. We show that the impulse response of the fully packaged HEB at 7.5 K has a 3 dB cutoff around 2 GHz. Remarkably, detection capability is still observed above 30 GHz in an heterodyne beating experiment using a THz quantum cascade laser frequency comb. Additionally, the HEB sensitivity has been evaluated and an optical noise equivalent power NEP of 0.8 pW/√H z has been measured at 1 MHz.

Early detection of Best's disease in childhood due to ineffective orthoptic treatment.

BACKGROUND: A meticulous fundoscopy is an essential examination before administering an orthoptic occlusion therapy (patching), even in cases with a "clear indication" for patching. In this case of an 8-year-old hyperopic boy the subsequent fundoscopy revealed a bilateral maculopathy that explained the stagnation of the increase of the monocular visual acuity (VA) in spite of a correctly applied patching. HISTORY AND SIGNS: The patient was a boy (8 years old) with a history of ineffective orthoptic treatment for 15 months due to hyperopia. Complete ophthalmological examination, optical coherence tomography (Cirrus HD-OCT, Zeiss, Germany) and electro-oculography (EOG) were performed. No "everyday" symptoms were found. Best corrected VA (hyperopic) on the right was 10 / 20, on the left 8 / 20. Binocular VA was 20 / 20. 15 out of 15 Ishihara plates were identified on both sides. Orthophoria has been seen. Perimetry revealed bilateral nasal-parafoveal microscotoma. Fundoscopy showed a confined and slightly prominent yellow spot on the temporal side of the fovea. OCT revealed a subfoveal accumulation of solid material in the RPE in both eyes. EOG showed normal findings in our case. THERAPY AND OUTCOME: There was no further deterioration of VA in a follow-up time of 12 months. CONCLUSIONS: Ineffective orthoptic treatment (patching) in amblyopic children should prompt the ophthalmologist to a meticulous fundoscopy, even if done so before patching, which is highly recommended. This young patient had no "everyday" visual symptoms. Because mainly the temporal fovea on both sides was affected, he showed normal binocular VA inspite of bilateral VA reduction. The authors think that this effect is due to biretinal summation (retinal filling in).

[Balloon dilatation of the canaliculus communis for chronic epiphora]. / Therapie von Canaliculus-communis-Stenosen mittels Ballonkatheterdilatation.

PURPOSE: To examine the clinical outcome of the balloon dilatation in stenosis of the canaliculus communis. METHOD: 18 nasolacrimal ducts with epiphora and proven obstruction of the canaliculus communis by dacryocystography (DCG) were treated with balloon dilatation in local anaesthesia. All patients were treated electively. RESULTS: In 16/18 cases the balloon dilatation was technically successful, in 2 patients the guide wire failed to pass the obstruction and the wire could not be placed in the nasal cavity. There were no complications. Over a mean follow-up of 6 months there were 2 reobstructions, one of these led to an occlusion of the canaliculus communis. 14/18 (77,8%) cases after DCP were treated successful, 11/18 cases were free of symptoms after DCP, in 4/18 cases the epiphora improved. CONCLUSIONS: Until recently in stenosis of the canaliculus communis the only therapeutic option was surgical procedure followed by silicone tube intubation. The results were often disappointing. In contrast to this balloon dacryocystoplasty is a minimally-invasive alternative in the therapy of stenosis of the canaliculus communis resulting in good clinical outcome during follow up.

[Balloon dilatation and Stentimplantation of the nasolacrimal duct for chronic epiphora]. / Minimal-invasive Therapie der Epiphora durch Ballonkatheterdilatation und Stentimplantation.

PURPOSE: To examine the clinical outcome of the ballon dilatation in stenosis and obstruction of the nasolacrimal duct. MATERIAL AND METHODS: 63 patients (69 nasolacrimal duct systems) with epiphora and proven obstruction of the nasolacrimal duct were treated with ballon dilatation, respectively Stentimplantation. In 55 cases there was a pre- or postsaccal stenosis, in 14 cases an occlusion of the nasolacrimal duct system. The diagnosis was established by dacryocystography. RESULTS: Technical success was obtained in 61 cases (n=50/55 stenosis; n=11/14 occlusions). Over a mean follow-up of 6 months patency of the nasolacrimal duct system was achieved in 83,6% (46/55) in stenosis. In occlusion the clinical outcome was 42,9% (6/14). CONCLUSION: Balloon dacryocystoplasty and Stentimplantation are minimal-invasive alternatives, performed in local anesthesia that recover the normal anatomy of the nasolacrimal duct system. They are a good alternative in the treatment of epiphora caused by nasolacrimal duct obstructions.

Bilateral non-arteritic anterior ischemic optic neuropathy in a patient with autoimmune thrombocytopenia.

PURPOSE: To describe a patient with bilateral non-arteritic anterior ischemic optic neuropathy (NAION) and idiopathic autoimmune thrombocytopenia (ITP) with an extremely low platelet count. METHOD: Case report. RESULTS: Remarkably good recovery of visual acuity. CONCLUSIONS: Bilateral non-arteritic anterior ischemic optic neuropathy can develop in the presence of a very low platelet count.

[Retrobulbar neuritis--diagnosis and differential diagnosis]. / Retrobulbärneuritis--Diagnostik und Differentialdiagnose.

The American multicenter study 'A randomized, controlled trial of corticosteroids in the treatment of acute optic neuritis' (5) showed how a retrobulbar neuritis should not be treated, Oral steroids (1 mg per kilogram of body weight per day) are not only ineffective but also associated with a higher rate of recurrences compared to high dose i.v. methylprednisolone. In the light of this study, 'low-dose' steroid therapy for retrobulbar neuritis is contraindicated. High-dose methylprednisolone speeds up recovery of the visual function and lowers the recurrence rate two years after treatment; however, this protective effect could not be demonstrated after three years. These recommendations are valid only for primary demyelinating retrobulbar neuritis. Other less common optic neuropathies, such as these of microvascular origin, respond to 'low-dose' steroids; therefore, the diagnosis of primary demyelinating retrobulbar neuritis must be made with caution as a diagnosis of exclusion. This paper discusses a number of important optic neuropathies and gives recommendations for investigations. Compressive optic neuropathies and chiasmal disease will not be covered here.

[Endonasal dacryocystorhinostomy with transillumination of the lacrimal sac: implementation and results]. / Die endonasale Dacryocystorhinostomie mit Transillumination des Tränensackes: Durchführung und Resultate.

PATIENTS: Since Mai 1991 we performed a total of 17 endonasal dacryocystorhinostomies under transillumination of the lacrimal sac on 15 patients with lacrimal obstruction aged 11 to 88 years. 11 patients with 12 operations were followed up between 40 and 393 days (mean of 5.6 months). RESULTS: In all cases the connection between the lacrimal sac and the nasal cavity remained functionally open. One patient developed a secondary canalicular stenosis which made silicon tubing necessary. CONCLUSIONS: We consider the operation an elegant and as far as our experience goes reliable method to recanalize the lacrimal drainage system avoiding a cutaneous incision. It is simplified by the transillumination of the lacrimal sac under videoendoscopic conditions.

[Indications for biopsy of the temporal artery]. / Indikationen zur Biopsie der Arteria temporalis.

Indications for Temporal Artery Biopsy are often discussed in the diagnosis of temporal arteritis. In this retrospective study we have reviewed the clinical records of 150 patients who underwent temporal artery biopsy between 1983 and 1990 in Kantonsspital Aarau/Switzerland. In 18.6% biopsies were histologically classified as temporal arteritis. To judge the indication for temporal artery biopsy the combination of symptoms leading to biopsy and the histologic results were compared. Symptoms were divided in unspecific, such as fever, loss of weight or malaise, and more specific symptoms as headache, jaw claudication, loss of visual acuity and diplopia, tenderness of temporal artery, or polymyalgia rheumatica. In conclusion the result of this study is that temporal artery biopsy may be an important help in the diagnosis of temporal arteritis in cases with one or two specific symptoms, at which polymyalgia rheumatica is a questionable indication. In our opinion temporal artery biopsy is not indicated in cases with isolated elevation of ESR, one or more unspecific symptoms and three or more specific symptoms, because there no diagnostic profit can be suspected.

[Long-term study following photocoagulation in diabetic retinopathy]. / Langzeitbeobachtungen nach Photokoagulation bei diabetischer Retinopathie.

Diabetic Retinopathy can be stabilized for years by ophthalmological measures. Proliferation in slowed down by photocoagulation and laser coagulation, but they do not prevent other vascular complications. Angiopathy of the arteries and arterioles of the retina and optic nerve can lead to additional, unexpected complications.

Septo-optic pituitary dysplasia. Observations on three patients.

Septo-optic pituitary dysplasia is a relatively rare but pathophysiologically interesting malformation of the brain midline structures including optic chiasm and nerves, hypothalamus, neurohypophysis and septum pellucidum. The lesion develops between the 5th and 8th week of pregnancy. The cause is unknown but heredity seems unlikely. Symptoms result from hypothalamic and neurohypophyseal insufficiency of variable severity combined with reduced vision due to hypoplasia of optic nerves and chiasm. Prognosis is variable, depending on the severity of the defect as well as on the earliest time of diagnosis followed by suitable hormone substitution and specialized care of blindness. We present the clinical course in three patients and the pathological findings in one patient who died in the 14th month of life.