Diagnosis and Treatment of Inhalation Injury in Burn Patients
Jacob Loke in Pathophysiology and Treatment of Inhalation Injuries, 2020
Intermittent mandatory ventilation (IMV), first introduced as a weaning technique (Downs et al., 1973), is much preferred over the CMV mode for providing ventilatory support in the spontaneously breathing patient exhibiting respiratory insufficiency. Since IMV produces lower inflation pressures and permits a lesser number of CMV breaths per unit time, it interferes less with the normally negative intrapleural pressures and thus impedes venous return and cardiac output to a lesser degree (Downs et al., 1977; Kirby et al., 1975). In spontaneous breathing, ventilation and perfusion are closely matched and the dependent regions of the lung are preferentially perfused (West, 1974). Thus IMV, which allows spontaneous respiration, permits an optimal ventilationperfusion matching, reduces intrapulmonary shunt, and improves oxygenation.
The neonate
Louise C Kenny, Jenny E Myers in Obstetrics, 2017
Preterm babies are prone to atelectasis because the chest is less stiff than it is in other age groups. This is most marked immediately after birth when low levels of surfactant mean that surface tension also is very high. These problems are overcome by applying a positive end expiratory pressure. This can be done using continuous positive airway pressure (CPAP) or intermittent mandatory ventilation (IMV). CPAP is administered nasally: a variety of delivery devices is available. IMV is administered with an endotracheal tube (ETT) (i.e. by intubation). If a baby is not breathing well then surfactant is administered. This can be done through an ETT or during CPAP by visualizing the vocal cords and placing a tube into the trachea while surfactant is administered. The choice between these methods depends on local preference and practice. Commercially available surfactants are carefully prepared extracts of pig or cow lung or are completely synthetic.
Pediatric ICU management
David E. Wesson, Bindi Naik-Mathuria in Pediatric Trauma, 2017
Two of the most commonly used conventional modes of ventilation are assist-control (A/C) and synchronized intermittent mandatory ventilation (SIMV) with or without pressure support (PS). In A/C ventilation, the ventilator delivers a preset rate and VT but will allow for additional breaths to be delivered (at the same level of support) when the patient initiates inspiration. Importantly, the patient cannot breathe independently of the ventilator, and the respiratory cycle may occur at irregular intervals depending on effort. In SIMV, the ventilator delivers preset breaths in coordination with the respiratory effort. If, however, no effort is detected at an interval determined by the preset rate, then a fully supported, mandatory breath will be delivered. This has the advantage of avoiding potential harm to the patient by delivering a mechanical breath when the patient is in mid- or end-inspiration. Spontaneous breathing is allowed between breaths, and the ventilator may be set to provide anywhere from no support to the same amount of support delivered with the mandatory breaths (depending on the set value for PS). Steps to initiate conventional ventilation are detailed in Table 11.4.
Care of children with home mechanical ventilation in the healthcare continuum
Published in Hospital Practice, 2021
Benjamin Kalm, Khanh Lai, Natalie Darro
There is limited evidence to inform the in-hospital care of children with new tracheostomies who require long-term mechanical ventilation. HMV is usually initiated in the hospital in consultation with pulmonary and otolaryngology teams. Discussion on optimal home ventilator, modes, and settings is beyond the scope of this article and varies based on local clinicians’ experience, preference, and availability of various equipment brands for both home health companies and hospitals. Home ventilators work in various modes including pressure or volume-controlled modes. Monitoring of ventilator parameters includes assessment of peak inspiratory pressure, positive end expiratory pressure, exhaled tidal volumes, respiratory rate, minute ventilation and leak. Home ventilators are set to alarm if there are high or low respiratory rates, minute ventilation, or pressure, as well if there is a circuit disconnect. At our institution patients utilize Trilogy ventilators as their home ventilator (either Trilogy 100 or Trilogy EVO). While modes of ventilation at other institutions may vary, children with HMV at our institution are preferentially placed on pressure control-synchronized intermittent mandatory ventilation (PC-SIMV), primarily for a standardized and consistent approach across providers. Newer ventilator modes such as pressure regulated volume control (PRVC) are not supported by our home ventilators.
Impact of early versus late tracheotomy on diaphragmatic function assessed by ultrasonography in mechanically ventilated stroke patients
Published in Egyptian Journal of Anaesthesia, 2022
Amr Abdalla Elsayed, Mohammed Refaat Mousa, Bassem Nashaat Beshey
All patients upon intubation were consecutively ventilated using synchronized intermittent mandatory ventilation mode. Ventilator was set to deliver tidal volume 6–8 ml/kg, respiratory rate 10–16/minute to allow for spontaneous breathing, positive end-expiratory pressure 5 cm.H2O, and pressure support (PS) 15 cm.H2O. They were subjected on admission to collection of demographic data (age and sex), patients’ comorbidities, site of stroke (according to brain CT findings), indication for intubation, and SET score (Table 1). The SET score was used as a screening tool for anticipating prolonged intubation in stroke patients with a score of more than 8. Dysphagia was assessed by a non-successful swallowing test, impaired saliva handling, or loss/reduction of gag reflex. For each physiological variable, the worst value in the first 24 hours after admission was used to achieve an estimation as early as possible [4,5].
Hypothesis: Fever control, a niche for alpha-2 agonists in the setting of septic shock and severe acute respiratory distress syndrome?
Published in Temperature, 2018
F. Petitjeans, S. Leroy, C. Pichot, A. Geloen, M. Ghignone, L. Quintin
By contrast, cooling febrile CCU patients reduces VO2 by ≈8–10% per °C [14]. In paralyzed sedated patients under controlled mechanical ventilation, surface cooling (39.4±0.8 °C to 37.0±0.5) decreases VO2 (359±65 to 295±57 mL.min-1; aggregated data: −18%) [29]. In one mild shivering patient, lowering temperature to 36.2°C reduces VO2 by −39%. VCO2 is lowered (303±43 to 243±37 mL.min-1:−20%). This is relevant when low driving pressure [30] and permissive hypercapnia [31] are considered in the setting of ARDS (“protective” ventilation). Cardiac output, O2 extraction ratio2 and HR decrease (respectively: 8.4±3.2 L.min-1 to 6.5±1.8 L.min-1, 28±7 to 23±5% and 119±21 to 102±14 bpmin). Mixed venous SO2 increases from 68±8 to 71±6% (ns). Therefore, mechanical ventilation, paralysis, and cooling (from 40 to 36° C) could reduce V02 in febrile, critically ill patients by as much as 190 mL/min, lowering metabolic demand by 47%: the manipulation of VO2 is a salvage therapy in severe shock or hypoxemic respiratory failure, e.g. for febrile, mechanically ventilated patients who do not respond to sedation and antipyretics [29]. In the setting of synchronized intermittent mandatory ventilation (n = 8) or pressure support (n = 10), external cooling lowered minute ventilation (39.1 to 37°C: 14.7±1 to 13.1 ±0.9 L.min-1: −11%) and decreased energy expenditure (−12%; sedation: morphine+midazolam to Ramsay 3–4) [32]. In this trial [32], only subsets of « septic episode » or severe hypoxia were studied [32].
Related Knowledge Centers
- Lung Compliance
- Pressure Support Ventilation
- Modes of Mechanical Ventilation
- Continuous Mandatory Ventilation
- Life Support