Prognostic value of pulmonary diffusing capacity for carbon monoxide and ventilation-perfusion SPECT findings in pulmonary arterial hypertension.

Reduced pulmonary diffusing capacity for carbon monoxide (DLCO) can be observed in pulmonary arterial hypertension (PAH) and associates with increased mortality. However, the prognostic value of DLCO when corrected for haemoglobin (DLCOc), an independent modifier of DLCO, remains understudied. Additionally, the prognostic role of ventilation (V)-perfusion (Q) emission computed tomography (V/Q SPECT) findings in patients with PAH, which may concurrently be performed to rule out chronic thromboembolic pulmonary hypertension, is uncertain. A retrospective cohort study was conducted on 152 patients with PAH referred to a tertiary hospital for evaluation from January 2011 to January 2020. Lung function tests, clinical data and V/Q SPECT were ascertained. Cox regression analysis was performed to evaluate the association between DLCOc, DLCO and V/Q SPECT defects at referral with all-cause mortality. In equally adjusted Cox regression analysis, each percentage increase in DLCOc % predicted (%pred) (hazard ratio (HR) 0.97; 95% CI: 0.94-0.99) and DLCO%pred (HR 0.97; 95% CI: 0.94-0.99) was similarly associated with all-cause mortality. There was no detectable difference in area under the curve for prediction of all-cause mortality by DLCOc%pred and DLCO%pred (C-index 0.71 and 0.72, respectively, P = 0.85 for difference). None of the defects noted on V/Q SPECT were significantly associated with mortality, but mismatched defects were associated with lower values of DLCOc%pred and DLCO%pred. DLCOc%pred and DLCO%pred perform equally as prognostic markers in PAH, supporting the use of either metric when available for prognostic stratification.

Pulmonary diffusing capacity to nitric oxide and carbon monoxide during exercise and in the supine position: a test-retest reliability study.

NEW FINDINGS: What is the central question in this study? How reliable is the combined measurement of the pulmonary diffusing capacity to carbon monoxide and nitric oxide (DLCO/NO ) during exercise and in the resting supine position, respectively? What is the main finding and its importance? The DLCO/NO technique is reliable with a very low day-to-day variability both during exercise and in the resting supine position, and may thus provide a useful physiological outcome that reflects the alveolar-capillary reserve in humans. ABSTRACT: DLCO/NO , the combined single-breath measurement of the diffusing capacity to carbon monoxide (DLCO ) and nitric oxide (DLNO ) measured either during exercise or in the resting supine position may be a useful physiological measure of alveolar-capillary reserve. In the present study, we investigated the between-day test-retest reliability of DLCO/NO -based metrics. Twenty healthy volunteers (10 males, 10 females; mean age 25 (SD 2) years) were randomized to repeated DLCO/NO measurements during upright rest followed by either exercise (n = 11) or resting in the supine position (n = 9). The measurements were repeated within 7 days. The smallest real difference (SRD), defined as the 95% confidence limit of the standard error of measurement (SEM), the coefficient of variance (CV), and intraclass correlation coefficients were used to assess test-retest reliability. SRD for DLNO was higher during upright rest (5.4 (95% CI: 4.1, 7.5) mmol/(min kPa)) than during exercise (2.7 (95% CI: 2.0, 3.9) mmol/(min kPa)) and in the supine position (3.0 (95% CI: 2.1, 4.8) mmol/(min kPa)). SRD for DLCOc was similar between conditions. CV values for DLNO were slightly lower than for DLCOc both during exercise (1.5 (95% CI: 1.2, 1.7) vs. 3.8 (95% CI: 3.2, 4.3)%) and in the supine position (2.2 (95% CI: 1.8, 2.5) vs. 4.8 (95% CI: 3.8, 5.4)%). DLNO increased by 12.3 (95% CI: 11.1, 13.4) and DLCOc by 3.3 (95% CI: 2.9, 3.7) mmol/(min kPa) from upright rest to exercise. The DLCO/NO technique provides reliable indices of alveolar-capillary reserve, both during exercise and in the supine position.

Peer instruction versus conventional group work-based teaching in a laboratory exercise on respiratory physiology: a randomized study.

Collaborative teaching strategies such as peer instruction and conventional group work have previously been shown to enhance meaningful learning, but they have not previously been compared. In this present study, we compared the impact of solving quizzes with peer instruction and conventional group work on immediate learning in a laboratory exercise. A total of 186 second-year medical students were randomized to solve two quizzes by either a peer instruction strategy (n = 93) or conventional group work (n = 93) during a mandatory laboratory exercise on respiratory physiology, after which all students completed an individual test. There was no difference in total test scores between groups, but students randomized to peer instruction obtained the highest test scores in solving simple integrated questions. Conversely, students randomized to conventional group work provided the best evaluations of the overall assessment of the laboratory exercise. In conclusion, different collaborative teaching strategies implemented during a laboratory exercise appear to affect immediate learning and student satisfaction differently.

Beak-type fractures of the calcaneus.

Beak fractures represent a rare subtype of calcaneal fractures with potential risk of soft tissue complications due to compromised local perfusion. Early diagnosis and timely intervention are crucial to prevent necrosis, infection, and soft tissue defects. This case report describes a 71-year-old male with a beak fracture and delayed intervention with reoccurring soft tissue defects. Given the rarity of the condition, atypical presentation and need for urgent intervention, this emphasizes the importance of awareness of beak fractures of the calcaneus.

Ramsay Hunt syndrome with viral meningitis.

Ramsay Hunt syndrome (RHS) is an infection with the Varicella Zoster virus in the geniculate ganglion of the facial nerve. The syndrome consists of a triad of peripheral facial nerve palsy, ear pain and concurrent zoster rash in the ear canal. However, vesicles in the mouth can be seen. A rare complication of RHS is viral meningitis. This is a case report of a patient with orally manifested RHS and concurrent asymptomatic viral meningitis. This case aims to raise awareness of RHS with atypical presentation and concurrent viral meningitis and, thereby, the importance of a thorough neurological examination.

Pulmonary blood volume measured by 82Rb-PET in patients with chronic obstructive pulmonary disease: a retrospective cohort study.

In patients with chronic obstructive pulmonary disease (COPD), pulmonary vascular dysfunction and destruction are observable before the onset of detectable emphysema, but it is unknown whether this is associated with central hypovolemia. We investigated if patients with COPD have reduced pulmonary blood volume (PBV) evaluated by 82Rb-positron emission tomography (PET) at rest and during adenosine-induced hyperemia. This single-center retrospective cohort study assessed 6,301 82Rb-PET myocardial perfusion imaging (MPI) examinations performed over a 6-yr period. We compared 77 patients with COPD with 44 healthy kidney donors (controls). Cardiac output ([Formula: see text]) and mean 82Rb bolus transit time (MBTT) were used to calculate PBV. [Formula: see text] was similar at rest (COPD: 3,649 ± 120 mL vs. control: 3,891 ± 160 mL, P = 0.368) but lower in patients with COPD compared with controls during adenosine infusion (COPD: 5,432 ± 124 mL vs. control: 6,185 ± 161 mL, P < 0.050). MBTT was shorter in patients with COPD compared with controls at rest (COPD: 8.7 ± 0.28 s vs. control: 11.4 ± 0.37 s, P < 0.001) and during adenosine infusion (COPD: 9.2 ± 0.28 s vs. control: 10.2 ± 0.37 s, P < 0.014). PBV was lower in patients with COPD, even after adjustment for body surface area, sex, and age at rest [COPD: 530 (29) mL vs. 708 (38) mL, P < 0.001] and during adenosine infusion [COPD: 826 (29) mL vs. 1,044 (38) mL, P < 0.001]. In conclusion, patients with COPD show evidence of central hypovolemia, but it remains to be determined whether this has any diagnostic or prognostic impact.NEW & NOTEWORTHY The present study demonstrated that patients with chronic obstructive pulmonary disease (COPD) exhibit central hypovolemia compared with healthy controls. Pulmonary blood volume may thus be a relevant physiological and/or clinical outcome measure in future COPD studies.

Dual Test Gas Pulmonary Diffusing Capacity Measurement During Exercise in Humans Using the Single-Breath Method.

The combined single-breath measurement of the diffusing capacity of carbon monoxide (DL,CO) and nitric oxide (DL,NO) is a useful technique to measure pulmonary alveolar-capillary reserve in both healthy and patient populations. The measurement provides an estimate of the participant's ability to recruit and distend pulmonary capillaries. The method has recently been reported to exhibit a high test-retest reliability in healthy volunteers during exercise of light to moderate intensity. Of note, this technique permits up to 12 repeated maneuvers and only requires a single breath with a relatively short breath-hold time of 5 s. Representative data are provided showing the gradual changes in DL,NO and DL,CO from rest to exercise at increasing intensities of up to 60% of maximal workload. The measurement of diffusing capacity and evaluation of alveolar-capillary reserve is a useful tool to evaluate the lung's ability to respond to exercise both in the healthy population as well as in patient populations such as those with chronic lung disease.

Lemierre syndrome.

Lemierre's syndrome is rare and characterized by an oropharyngeal infection with thrombophlebitis of the internal jugular vein (IJV). Septic microemboli can spread to the lungs or abdomen. This case describes a patient who presented with a sore throat, unilateral swelling on the neck and diffuse abdominal pain. Imaging showed a thrombus in the right IJV. The patient developed septic shock and was treated with antibiotics, anticoagulants, and intensive care support. The most common causative organism is Fusobacterium necrophorum. Early diagnosis and treatment are crucial for reducing mortality.

Post-injection delirium/sedation syndrome after treatment with olanzapine depot.

Treatment with olanzapine depot is associated with a rare but potentially adverse reaction, namely post-injection delirium/sedation syndrome (PDSS), characterized by delirium and/or sedation. This is a case report of a 38-year-old male patient who developed symptoms consistent with PDSS shortly after receiving intramuscular injection of olanzapine depot. Clinicians should be aware of PDSS and observe patients for three hours after receiving the injection, measuring vitals and referring to medical care if necessary.

Increased liver markers in rhabdomyolysis in a young recruit from the field trip.

We present a case report of rhabdomyolysis after intense physical activity. Tests showed increased creatine kinase compatible with rhabdomyolysis. Liver damage was suspected due to a significant elevation of aspartate transaminase (AST) and alanine transaminase (ALT). This case report discusses how an increase in AST and ALT reflects skeletal muscle damage in rhabdomyolysis instead of liver damage, especially when assessing more specific liver markers such as international normalised ratio and ϒ-glutamyl transferase, which both were within normal range in this case. This knowledge can prevent unnecessary test.

[Hyperlactataemia].

It is a common but flawed presumption that blood lactate reflects the lactic acid production in the body's tissues. Lactate is formed directly from pyruvate and functions to dampen reductions in intracellular pH through lactate-H+ cotransport to the extracellular space. Though this may give rise to elevated blood lactate, increased lactate production is not the cause of metabolic acidosis in such instances. "Lactic acidosis" is thus an inappropriate term as it indicates causality and in this review, we suggest that in the future, the term "hyperlactataemia-associated metabolic acidosis" should be used instead.

Prognostic impact of ventilation-perfusion defects and pulmonary diffusing capacity after single lung transplantation.

BACKGROUND: Ventilation-perfusion (VQ) scintigraphy and lung function testing are often used to assess allograft function after single lung transplantation (SLTX). However, it is unknown whether allograft defects on VQ scintigraphy presage all-cause mortality after SLTX. OBJECTIVE: To investigate whether allograft defects on VQ scintigraphy portend poorer lung function and increased mortality after SLTX. METHODS: We retrospectively identified 45 consecutive patients in which a VQ scintigraphy was performed as part of the routine workup 12 weeks after SLTX. VQ scintigraphies were scored for matched and mismatched perfusion defects in the allograft. Lung function testing was performed according to established guidelines six months after SLTX. Time to all-cause mortality was the endpoint. RESULTS: 19 (42%) patients had matched VQ defects. After a median follow-up of 4.1 (IQR 1.5-7.9) years since SLTX, 35 (78%) had died. Those with matched defects in the allograft had lower diffusing capacity (mean 42 [SD 14] versus mean 54 [SD 18] % of predicted, p < .05) and increased mortality (univariable HR 2.06, 95% CI: 1.05-4.06, p = .04). However, in multivariate analysis, only lower post-transplantation diffusing capacity remained associated with mortality (HR 1.08, 95% CI: 1.02-1.30 per % lower diffusing capacity of predicted, p = .003). CONCLUSION: In SLTX patients, a lower diffusing capacity appeared to explain the increased mortality among those with matched VQ defects in the allograft.