Real-time versus thermal desorption selected ion flow tube mass spectrometry for quantification of breath volatiles.

RATIONALE: Selected ion flow tube mass spectrometry (SIFT-MS) is versatile, rapidly provides result output and determines a wide range of volatiles, making it suitable for biomedical applications. When direct sampling into the SIFT-MS instrument is impractical, combining thermal desorption (TD) and SIFT-MS might offer a solution as it allows sample storage on sorbent tubes for later analysis. This work compares off-line TD SIFT-MS and real-time SIFT-MS for the quantification of selected breath volatiles. METHODS: Ten healthy non-smoking individuals provided 60 breath samples per method. For off-line analysis, breath was collected onto sorbent tubes via a breath sampler provided with filtered inspiratory air. After TD, samples were re-collected in Tedlar bags which were then connected to the SIFT-MS instrument. For real-time analysis, breath was sampled directly into the instrument. In both cases the analytical method included a total of 155 product ions, and 14 selected volatiles were quantified. The agreement between the methods was assessed using Pearson correlation coefficients and Bland-Altman plots. RESULTS: Overall, correlations between real-time and off-line analysis were moderate to very strong (r = 0.43-0.92) depending on the volatile of interest, except for 2,3-butanedione and styrene. The difference between real-time and off-line measured breath concentrations (average bias) ranged between -14.57 and 20.48 ppbv. For acetone and isoprene, it was 251.53 and 31.9 ppbv, respectively. CONCLUSIONS: Real-time SIFT-MS and off-line TD SIFT-MS for quantification of selected breath volatiles did not show optimal agreement. Analyzing a multitude of analytes in breath via direct exhalation into a SIFT-MS instrument for real-time analysis is challenging. On the other hand, off-line analysis using a breath collection device also has its issues such as possible sample losses due to selective absorption depending on the sorbent used or during desorption and transfer to the instrument. Despite these drawbacks, both methods were moderately well correlated.

Percutaneous closure of patent foramen ovale for the secondary prevention of decompression illness in sports divers: mind the gap.

OBJECTIVE: To evaluate the efficiency of percutaneous patent foramen ovale (PFO) closure on the recurrence of decompression illness (DCI). DESIGN: Retrospective, observational study with interview and questionnaire. SETTING: Tertiary referral center. POPULATION: 59 scuba divers with a history of DCI who received a percutaneous PFO closure. MAIN OUTCOME MEASUREMENTS: Questionnaire about health status, dive habits and recurrence of DCI after PFO closure. RESULTS: A total of 59 divers with DCI were included. The most common manifestations of DCI were cutaneous or vestibular DCI. Procedural complications occurred in four patients but none with long-term consequences. Four patients had recurrence of DCI after closure during a 10-year follow-up. In three of these cases there was residual shunting, all of which were initially considered closed. The fourth patient had aggravating factors for his recurrent DCI. A quarter of the patients stated to have changed their diving habits. Four patients quit diving. CONCLUSION: Percutaneous PFO closure for secondary prevention of DCI is associated with few, but not negligible, complications. As a large portion of our cohort changed their diving habit after closure it is difficult to ascertain the efficiency of PFO closure for secondary prevention of DCI. However, the study shows that PFO closure does not fully protect against DCI, emphasizing that the relationship between PFO and DCI is but an association. As such it is imperative that divers be counseled to ensure they understand the risks as well as the benefits of percutaneous PFO closure in their specific case.

Severe tricuspid regurgitation and seizure on postpartum day 10: case report of late postpartum eclampsia.

OBJECTIVE AND IMPORTANCE: Late postpartum eclampsia is characterized by pre-eclampsia and tonic-clonic seizures presenting more than 48 hours postpartum. It is a rare, frightening and dangerous complication that requires rapid recognition and adequate treatment. CLINICAL PRESENTATION: We present a case of late postpartum eclampsia, initially diagnosed as right-sided heart failure, 10 days postpartum.Two days after the delivery she developed mild swelling of both feet, progressive shortness of breath on exertion and orthopnea. INTERVENTION: Transthoracic echocardiography revealed sever tricuspid regurgitation in combination with pulmonary hypertension. The patient wasadmitted to the intensive care unit (ICU) and a tentative diagnosis of pulmonary hypertension was made. On arrival in the ICU, the patient developed a tonic-clonic seizure and urinalysis revealed proteinuria, indicating eclampsia. Treatment of eclampsia was initiated with complete resolution of symptoms. CONCLUSION: This caseemphasizes the importance of considering late postpartum eclampsia in patients presenting with signs of pulmonary edema even several days after delivery, as early diagnosis and prompt initiation of appropriate antihypertensive and anticonvulsant therapy can prevent severe complications.