Live stream of prehospital point-of-care ultrasound during cardiopulmonary resuscitation - A feasibility trial.

BACKGROUND: Current resuscitation guidelines recommend that skilled persons could use ultrasound to detect reversible causes during cardiopulmonary resuscitation (CPR) where the examination can be safely integrated into the Advanced Life Support (ALS) algorithm. However, in a prehospital setting performing and rapidly interpreting ultrasound can be challenging for physicians. Implementing remote, expert-guided, and real-time transmissions of ultrasound examinations offers the opportunity for tele-support, even during an out-of-hospital cardiac arrest (OHCA). The aim of this feasibility study was to evaluate the impact of tele-supported ultrasound in ALS on hands-off time during an OHCA. METHODS: In an urban setting, physicians performed point-of-care ultrasound (POCUS) on patients during OHCA using a portable device, either with tele-support (n = 30) or without tele-support (n = 12). Where tele-support was used, the ultrasound image was transmitted via a remote real-time connection to an on-call specialist in anaesthesia and intensive care medicine with an advanced level of critical care ultrasound expertise. The primary safety endpoint of this study was to evaluate whether POCUS can be safely integrated into the algorithm, and to provide an analysis of hands-off time before, during, and after POCUS during OHCA. RESULTS: In all 42 cases it was possible to perform POCUS during regular rhythm analyses, and no additional hands-off time was required. In 40 of these 42 cases, the physicians were able to perform POCUS during a single regular rhythm analysis, with two periods required only in two cases. The median hands-off time during these rhythm analyses for POCUS with tele-support was 10 (8-13) seconds, and 11 (9-14) seconds for POCUS without tele-support. Furthermore, as a result of POCUS, in a quarter of all cases the physician on scene altered their diagnosis of the primary suspected cause of cardiac arrest, leading to a change in treatment strategy. CONCLUSIONS: This feasibility study demonstrated that POCUS with tele-support can be safely performed during OHCA in an urban environment. Trial Registration (before patient enrolment): ClinicalTrials.gov, NCT04817475.

Continuously tunable diamond Raman laser for resonance laser ionization.

We demonstrate a highly efficient, tunable, ∼5 GHz linewidth diamond Raman laser operating at 479 nm. The diamond laser was pumped by a wavelength-tunable intracavity frequency-doubled titanium sapphire (Ti:Sapphire) laser operating at around 450 nm, at a repetition rate of 10 kHz with a pulse duration of 50 ns. The Raman resonator produced a continuously tunable output with high stability, high conversion efficiency (28%), and beam quality (M2<1.2). We also demonstrate that the linewidth and tunability of the pump laser is directly transferred to the Stokes output. Our results show that diamond Raman lasers offer great potential for spectroscopic applications, such as resonance laser ionization, in an all-solid-state platform.

Fibrinogen but not factor XIII deficiency is associated with bleeding after craniotomy.

BACKGROUND: Postoperative haemorrhage in neurosurgery is associated with significant morbidity and mortality. There is controversy whether or not factor XIII (FXIII) deficiency leads to bleeding complications after craniotomy. Decreased fibrinogen levels have been associated with an increased incidence of bleeding complications in cardiac and orthopaedic surgery. The aim of this study was to assess perioperative fibrinogen and FXIII levels in patients undergoing elective intracranial surgery with and without severe bleeding events. METHODS: Perioperative FXIII and fibrinogen levels were prospectively assessed in 290 patients undergoing elective craniotomy. Patients were divided into two groups according to the presence or absence of severe bleeding requiring surgical revision. Coagulation test results of these groups were compared using Student's t-test. RESULTS: The incidence of postoperative severe bleeding was 2.4%. No differences in FXIII levels were observed, but postoperative fibrinogen levels were significantly lower in patients suffering from postoperative haematoma compared with those without postoperative intracranial bleeding complications [237 mg dl(-1) (standard deviation, SD 86) vs 170 mg dl(-1) (SD 35), P=0.03]. The odds ratio for postoperative haematoma in patients with a postoperative fibrinogen level below 200 mg dl(-1) was 10.02 (confidence interval: 1.19-84.40, P=0.03). CONCLUSIONS: This study emphasizes the role of fibrinogen as potentially modifiable risk factor for perioperative bleeding in intracranial surgery. Future randomized controlled trials will be essential to identify patients who might benefit from fibrinogen substitution during neurosurgical procedures.