Lung volumes, respiratory mechanics and dynamic strain during general anaesthesia.

BACKGROUND: Driving pressure (ΔP) represents tidal volume normalised to respiratory system compliance (CRS) and is a novel parameter to target ventilator settings. We conducted a study to determine whether CRS and ΔP reflect aerated lung volume and dynamic strain during general anaesthesia. METHODS: Twenty non-obese patients undergoing open abdominal surgery received three PEEP levels (2, 7, or 12 cm H2O) in random order with constant tidal volume ventilation. Respiratory mechanics, lung volumes, and alveolar recruitment were measured to assess end-expiratory aerated volume, which was compared with the patient's individual predicted functional residual capacity in supine position (FRCp). RESULTS: CRS was linearly related to aerated volume and ΔP to dynamic strain at PEEP of 2 cm H2O (intraoperative FRC) (r=0.72 and r=0.73, both P<0.001). These relationships were maintained with higher PEEP only when aerated volume did not overcome FRCp (r=0.73, P<0.001; r=0.54, P=0.004), with 100 ml lung volume increases accompanied by 1.8 ml cm H2O-1 (95% confidence interval [1.1-2.5]) increases in CRS. When aerated volume was greater or equal to FRCp (35% of patients at PEEP 2 cm H2O, 55% at PEEP 7 cm H2O, and 75% at PEEP 12 cm H2O), CRS and ΔP were independent from aerated volume and dynamic strain, with CRS weakly but significantly inversely related to alveolar dead space fraction (r=-0.47, P=0.001). PEEP-induced alveolar recruitment yielded higher CRS and reduced ΔP only at aerated volumes below FRCp (P=0.015 and 0.008, respectively). CONCLUSIONS: During general anaesthesia, respiratory system compliance and driving pressure reflect aerated lung volume and dynamic strain, respectively, only if aerated volume does not exceed functional residual capacity in supine position, which is a frequent event when PEEP is used in this setting.

Effective prevention of post-dural puncture headache with insertion of an intrathecal catheter in parturients: a retrospective study and meta-analysis.

BACKGROUND: Accidental dural puncture is a common complication of labour analgesia. It can trigger post-dural puncture headache, with associated morbidity and increased costs. Intrathecal catheter placement is a prophylactic procedure which can reduce incidence and severity of post-dural puncture headache. METHODS: We conducted a retrospective single-centred study to define incidence and risk factors of accidental dural puncture and post-dural puncture headache in an obstetric population. We also evaluated effectiveness of intrathecal catheter placement compared to epidural catheter replacement in reducing incidence of post-dural puncture headache. We then conducted a systematic review and meta-analysis which included all studies comparing intrathecal catheter placement to epidural catheter replacement in obstetric patients with accidental dural puncture assessing the outcome of reduced incidence of post-dural puncture headache as a dichotomous variable. RESULTS: Accidental dural puncture had an incidence of 0.25% (60 cases). Of these, 66% developed post-dural puncture headache. A total of 77% (47/60) of patients with accidental dural puncture were treated with an intrathecal catheter placement, while 23% (13/60) had an epidural catheter replacement. Incidence of post-dural puncture headache was lower in the intrathecal catheter group (spinal 26/47, 60.5% epidural 11/13, 84.6%), although not reaching statistical significance (RR 0.71, CI 95%: 0.51-1.00; p = 0.049). The meta-analysis revealed that intrathecal catheter placement significantly reduced incidence of post-dural puncture headache compared to epidural catheter replacement (pooled RR 0.81, 95% CI 0.72-0.91, p < 0.001). CONCLUSIONS: Intrathecal catheter placement is a promising measure to prevent post-dural puncture headache, especially if followed by a pain management protocol and a continuous saline infusion.

Taking Care of Relationships in the Intensive Care Unit: Positive Impact on Family Consent for Organ Donation.

BACKGROUND: Organ donation refusal from relatives of potential donors with brain death significantly reduces organ availability. The need for organ donation has increased over time, but the shortage of available donors is the major limiting factor in transplantation. We analyzed the impact of a new systematic communication approach between medical staff and patients' relatives on the rate of consent to organ donation. METHODS: The study was conducted as a single-center, non-randomized, controlled, before-and-after study at an 18-bed intensive care unit (ICU) of a university hospital. We compared the rate of consent for organ donation before and after the introduction of the new communication approach. RESULTS: A total of 291 brain-dead patients were studied. The consent rate increased from 71% in the pre-intervention period (2007-2012) to 78.4% in the post-intervention period (2013-2015), with an 82.75% increase in the 2014 to 2015 period. During these periods, no significant variation of consent to organ donation was recorded at the national and regional levels. CONCLUSIONS: The introduction of a new communication approach between medical staff and relatives of brain-dead patients was associated with a significant increase in the rate of consent to donation. Our results highlight the importance of empathy with relatives in the ICU.

New experimental Oximes in the management of organophosphorus pesticides poisoning.

Organophosphorus compounds (OPCs) are widely used in agriculture as pesticides and occasionally in industrial settings. They have also been developed as warfare nerve agents. OPCs poisoning from intentional, accidental, and occupational exposure is a major public health problem, especially across the rural developing world. The main toxic mechanism of OPCs is the inhibition of the enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), resulting in accumulation of acetylcholine (ACh) at the synapse with cholinergic crisis and possible death. Exposure to even small amounts of an OPC can be fatal and death is usually caused by respiratory failure. Standard treatment involves the administration of intravenous atropine and an oxime to counteract acetylcholinesterase inhibition at the synapse, but the usefulness of oximes is still debated. During more than five decades, pyridinium oximes have been developed as therapeutic agents used in the medical treatment of poisoning with OPCs. They act by reactivation of AChE inhibited by OPCs. However, their activity in poisonings with pesticides and warfare nerve agents is different, and there is still no universal oxime sufficiently effective against all known OPCs. The aim of this article was to review the most recent findings in this field and compare the protection conferred by the new K-oximes and sugar oximes with the effect of the four recommended pyridinium oximes (pralidoxime, obidoxime, trimedoxime, and HI-6), in the search for a broad-spectrum AChE reactivator.