Intensive Care Medicine

IntelliVent-ASV® is a development of adaptive support ventilation (ASV) that automatically adjusts ventilation and oxygenation parameters. This study assessed the safety and efficacy of IntelliVent-ASV® in sedated intensive care unit (ICU) patients with acute respiratory failure. This prospective randomized crossover comparative study was conducted in a 12-bed ICU in a general hospital. Two periods of 2 h of ventilation in randomly applied ASV or IntelliVent-ASV® were compared in 50 sedated, passively ventilated patients. Tidal volume (V T), respiratory rate (RR), inspiratory pressure (P INSP), SpO2 and ETCO2 were continuously monitored and recorded breath by breath. Mean values over the 2-h period were calculated. Respiratory mechanics, plateau pressure (P PLAT) and blood gas exchanges were measured at the end of each period. There was no safety issue requiring premature interruption of IntelliVent-ASV®. Minute ventilation (MV) and V T decreased from 7.6 (6.5–9.5) to 6.8 (6.0–8.0) L/min (p < 0.001) and from 8.3 (7.8–9.0) to 8.1 (7.7–8.6) mL/kg PBW (p = 0.003) during IntelliVent-ASV® as compared to ASV. P PLAT and FiO2 decreased from 24 (20–29) to 20 (19–25) cmH2O (p = 0.005) and from 40 (30–50) to 30 (30–39) % (p < 0.001) during IntelliVent-ASV® as compared to ASV. RR, P INSP, and PEEP decreased as well during IntelliVent-ASV® as compared to ASV. Respiratory mechanics, pH, PaO2 and PaO2/FiO2 ratio were not different but PaCO2 was slightly higher during IntelliVent-ASV® as compared to ASV. In passive patients with acute respiratory failure, IntelliVent-ASV® was safe and able to ventilate patients with less pressure, volume and FiO2 while producing the same results in terms of oxygenation.

Acute brain dysfunction or delirium occurs in the majority of mechanically ventilated (MV) medical intensive care unit (ICU) patients and is associated with increased mortality. Unfortunately delirium often goes undiagnosed as health care providers fail to recognize in particular the hypoactive form that is characterized by depressed consciousness without the positive symptoms such as agitation. Recently, clinical tools have been developed that help to diagnose delirium and determine the subtypes. Their use, however, has not been reported in surgical and trauma patients. The objective of this study was to identify the prevalence of the motoric subtypes of delirium in surgical and trauma ICU patients. Adult surgical and trauma ICU patients requiring MV longer than 24 h were prospectively evaluated for arousal and delirium using well validated instruments. Sedation and delirium were assessed using the Richmond Agitation Sedation Scale (RASS) and the Confusion Assessment Method in the ICU (CAM-ICU), respectively. Patients were monitored for delirium for a maximum of 10 days or until ICU discharge. A total of 100 ICU patients (46 surgical and 54 trauma) were enrolled in this study. Three patients were excluded from the final analysis because they stayed persistently comatose prior to their death. Prevalence of delirium was 70% for the entire study population with 73% surgical and 67% trauma ICU patients having delirium. Evaluation of the subtypes of delirium revealed that in surgical and trauma patients, hypoactive delirium (64% and 60%, respectively) was significantly more prevalent than the mixed (9% and 6%) and the pure hyperactive delirium (0% and 1%). The prevalence of the hypoactive or “quiet” subtype of delirium in surgical and trauma ICU patients appears similar to that of previously published data in medical ICU patients. In the absence of active monitoring with a validated clinical instrument (CAM-ICU), however, this subtype of delirium goes undiagnosed and the prevalence of delirium in surgical and trauma ICU patients remains greatly underestimated.

Application of the principles of oxygen transport in the management of critically ill patients can influence the frequency of organ failure and outcome. Adequate tissue oxygen consumption in these patients may depend on a supranormal level of oxygen delivery. The equations used for calculating oxygen delivery and consumption are provided, and it is noted that clinicians should have a clear understanding of the limitations of each of the measurements included in the equations. The methods used to perform the measurements are reviewed. Widespread acceptance and use of oxygen transport protocols in treatment is only possible if the measurements on which they are based are accurate and properly interpreted.

Intranasal cooling can be used to initiate therapeutic hypothermia. However, direct measurement of brain temperature is difficult and the intra-cerebral distribution of temperature changes with cooling is unknown. The purpose of this study was to measure the brain temperature of human volunteers subjected to intranasal cooling using non-invasive magnetic resonance (MR) methods. Intranasal balloons catheters circulated with saline at 20°C were applied for 60 min in ten awake volunteers. No sedation was used. Brain temperature changes were measured and mapped using MR spectroscopic imaging (MRSI) and phase-mapping techniques. Heart rate and blood pressure were monitored throughout the experiment. Rectal temperature was measured before and after the cooling. Mini Mental State Examination (MMSE) test and nasal inspection were done before and after the cooling. Questionnaires about the subjects’ personal experience were completed after the experiment. Brain temperature decrease measured by MRSI was −1.7 ± 0.8°C and by phase-mapping −1.8 ± 0.9°C (n = 9) at the end of cooling. Spatial distribution of temperature changes was relatively uniform. Rectal temperature decreased by −0.5 ± 0.3°C (n = 5). The physiological parameters were stable and no shivering was reported. The volunteers remained alert during cooling and no cognitive dysfunctions were apparent in the MMSE test. Postcooling nasal examination detected increased nasal secretion in nine of the ten volunteers. Volunteers’ acceptance of the method was good. Both MR techniques revealed brain temperature reductions after 60 min of intranasal cooling with balloons circulated with saline at 20°C in awake, unsedated volunteers.

Mycoplasma hominis is a well recognized extragenital pathogen. However, it is an uncommon cause of respiratory infections in critically ill patients admitted to the intensive care unit (ICU). Prospective clinical investigation in a 21-bed ICU in a university hospital. Seven patients requiring intensive care who developed a ICU-acquired pneumonia in which M. hominis was recovered from bronchoalveolar lavage and pleural fluid cultures. M. hominis was isolated in all patients by use of conventional bacteriological cultures. All strains were identified by 16S rRNA gene sequencing analysis. Patients' charts were reviewed for each case of infection. Seven strains of M. hominis were isolated during a 4-year period. All of these isolates were recovered from adult men admitted to the ICU and all had clinical signs of pneumonia. In three patients treatment for M. hominis with quinolones was associated with a good clinical response. Suspicion of M. hominis pneumonia must be heightened particularly in critically ill patients. Therefore an understanding of the microbiology of this organism is essential to successfully treat patients with these infections that are not ordinarily covered with standard antibiotic therapy.

Ultrasonography allows the direct observation of the diaphragm. Its thickness variation measured in the zone of apposition has been previously used to diagnose diaphragm paralysis. We assessed the feasibility and accuracy of this method to assess diaphragmatic function and its contribution to respiratory workload in critically ill patients under non-invasive ventilation. This was a preliminary physiological study in the intensive care unit of a university hospital. Twelve patients requiring planned non-invasive ventilation after extubation were studied while spontaneously breathing and during non-invasive ventilation at three levels of pressure support (5, 10 and 15 cmH2O). Diaphragm thickness was measured in the zone of apposition during tidal ventilation and the thickening fraction (TF) was calculated as (thickness at inspiration − thickness at expiration)/thickness at expiration. Diaphragmatic pressure–time product per breath (PTPdi) was measured from oesophageal and gastric pressure recordings. PTPdi and TF both decreased as the level of pressure support increased. A significant correlation was found between PTPdi and TF (ρ = 0.74, p < 0.001). The overall reproducibility of TF assessment was good but the coefficient of repeatability reached 18 % for inter-observer reproducibility. Ultrasonographic assessment of the diaphragm TF is a non-invasive method that may prove useful in evaluating diaphragmatic function and its contribution to respiratory workload in intensive care unit patients.

Adverse respiratory and gasometrical effects have been described in patients with acute respiratory failure (ARF) undergoing noninvasive ventilation (NIV) with standard heat and moisture exchangers (HME). We decided to evaluate respiratory parameters and arterial blood gases (ABG) of patients during NIV with small dead space HME compared with heated humidifier (HH). Prospective randomized crossover study. A 16-bed medical intensive care unit (ICU). Fifty patients receiving NIV for ARF. The effects of HME and HH on respiratory rate, minute ventilation, EtCO2, oxygen saturation, airway occlusion pressure at 0.1 s, ABG, and comfort perception were compared during two randomly determined NIV periods of 30 min. The relative impact of HME and HH on these parameters was successively compared with or without addition of a flex tube (40 and 10 patients, respectively). No difference was observed between HME and HH regarding any of the studied parameters, whether or not a flex tube was added. If one decides to humidify patients’ airways during NIV, one may do so with small dead space HME or HH without altering respiratory parameters.