Differential lung ventilation with a modified ventilator.

To achieve synchronized differential pulmonary ventilation, an Ohio 560 ventilator was modified through separation of the outputs of the deep breath bellows and the tidal volume bellows and providing independent volume, flow rate, PEEP, oxygen-humidification, and alarm systems. The described ventilator modification is simple, inexpensive, and does not alter the performance characteristics of the original unmodified ventilator. Differential lung ventilation may be more easily achieved with this modified ventilator than with the simultaneous use of two ventilators or external electronic synchronizers.

[Servo-ventilator 900 B with modified registration site for measuring the ventilation pressure. A possibility for reducing the inspiratory resistance during SIMV (author's transl)]. / Servo-Ventilator 900 B mit modifizierter Abnahmestelle für die Messung des Beatmungsdruckes. Eine Möglichkeit zur Verringerung des inspiratorischen Widerstandes bei SIMV.

The inspiratory resistance, which a patient has to overcome while doing SIMV and CPAP with a Servoventilator 900 B, can be lowered by a simple modification of the ventilator. This modification is done by measuring the ventilation-pressure at the patients side of the humidifier. Measurements of pressure and flow demonstrated that, with a flow of 11 s-1 a 66%-reduction of the inspiratory resistance can be achieved.

Uso racional de los respiradores / Mechanical ventilators: rational use

Los ventiladores son equipos de ayuda cuyo funcionamiento debe adaptarse a los requerimientos de un enfermo y como tal deben aplicarse con la debida "dosificacion" de acuerdo a la patologia diagnosticada, estableciendo previamente objetivos terapeuticos y controlando adecuadamente su funcionamiento y los resultados obtenidos, cuidando de disminuir al maximo o evitar sies posible las "acciones colaterales" de los mismos. Como norma general de conducta, utilizamos la PPI cuando una disminucion de la efectividad inspiratoria se traduce en un aumento importante del trabajo respiratorio y/o hipoventilacion alveolar (evidenciada en una retencion de CO2), utilizando preferencialmente la modalidad de VIO. or otro lado utilizamos la PPFE cuando una disminucion de la capacidad residual funcional produce una alteracion V/Q suficiente para producir una mezcla veno-arterial mayor o igual a 15% del gasto cardiaco con una FiO2 de 0,4 o menos. Si cincomitantemente se produce una hipoventilacion alveolar, asociamos PPI en la modalidad de VIO.Asociacion Colombiana de Medicina Interna

Relation between respiratory valve dead space and tidal volume.

We measured the "effective" dead space of five commonly used respiratory valves: Hans Rudolph valve, two-way J valve, triple-J valve, and modified Otis-McKerrow valves without and with vane. The dead space was measured using a technique that mimicked the operation of valves during ordinary laboratory procedures. The valves were ventilated with tidal volumes ranging from 0.35-3.00 liters and at different frequencies. With all valves, there was a marked tendency for "effective" dead space to be tidal volume dependent. The measured dead space approached the water-displacement volume of the common chamber of the valve only at tidal volumes in excess of 2.0 liters. The relation between valve dead space and tidal volume was independent of frequency.

[A new portable device for ventilatory support (author's transl)]. / Ein neues transportables Beatmungsgerät.

Transportation of patients requiring continuous ventilatory support and increased inspired oxygen concentrations may be troublesome for the physician and the nursing staff and dangerous for the patients. A new portable ventilator requiring oxygen of three atm. pressure as gas supply was tested for use during in-hospital transportation of more than 300 critically ill patients. Ventilator operation was simple, the machine was resistant to rude handling and the patients were ventilated reliably.

[Anaesthetic gas suction device for the Takaoka-Respirator ("Ventex") (author's transl)]. / Narkosegas-Absaugvorrichtung für den Takaoka-Respirator (Ventex).

Due to its basic principle the Takaoka-Respirator uses essentially a higher gas flow per minute then the normal anesthesia-circuit-system. In order to avoid any air-pollution we have recently constructed a special airtight plastic box (Ventex) with fittings for the respirator and its manometer.

[The Oxylog--a new ventilator for mobile use (author's transl)]. / Der Oxylog--ein neues Beatmungsgerät für den mobilen Einsatz.

A new volume limited ventilator for mobile use was tested on ventilator dependent patient of our intensive care unit and in rescue helicopter missions. Function, handling and constant volume were examined. The pros and cons are considered and discussed. We recommend this ventilator for emergency and transport.

Temperature alarm and cut-out system for use with heated water humidifiers.

The temperature of the inspired humidified gases of an intubated patient may be monitored accurately, close to the airway, by a commercially available thermistor probe and alarm/cut-out device for use with heated water humidifiers. The apparatus is designed to alarm when the inspired gas temperature exceeds the pre-set temperature and when the thermistor probe is in open or short circuit. When the temperature alarm is activated, the humidifier heater is switched off automatically, thus preventing prolonged transmission of excessively hot gases to the airway. The apparatus has been used successfully in this hospital for several months, requiring minimal observer attention and maintenance.

The Siemens-Elema Servo Ventilator 900 B for the management of newborn infants with severe respiratory distress syndrome: a 22-month trial.

The Siemens-Elema Servo Ventilator 900 B is an electronically-controlled, volume-limited ventilator. To adapt this ventilator for use in newborns with respiratory failure, minute volume control, PEEP valves, air-oxygen blenders, and respiratory tubing circuits were modified. During a 22-month period, 161 newborn infants with severe respiratory distress syndrome (RDS) were managed with this ventilator. The overall survival rate was 66%; the incidence of barotrauma was 20%; the survival rate was 53%. Of the infants studied, 12% developed bronchopulmonary dysplasia, and 79% of these survived. Of the 19% of patients with a symptomatic intraventricular hemorrhage, 6% survived. The experience of the authors with this ventilator modified to manage newborn infants with severe RDS has been extremely encouraging. Furthermore, this ventilator is versatile because it can be readily recalibrated for use in older patients and can be easily adapted for patients requiring surgery. This ventilator has the extremely important advantage of being a volume ventilator which can effectively provide positive pressure ventilatory support to patients of all age and weight groups.

Clinical studies of gas exchange during ventilatory support--a method using the Siemens-Elema CO2 analyzer.

We describe a new portable infra-red analyses for use with the Siemens-Elema Servo ventilator. The sensor head constitutes a Y-piece connecting the patient to the ventilator tubing, and gives instant carbon dioxide determination. It is based upon simple principles that can be realized with modern techniques, offering for instance freedom from interference by anaesthetic gases, and eliminating the need for calibration. A non-zero inspired carbon dioxide concentration interferes with the measurements. Integration of the carbon dioxide signal with the flow signal from the Servo ventilator yields data about carbon dioxide excretion, and additional calculation yields VD/VT if PaCO2 is known. The accuracy of determination of end-tidal carbon dioxide and carbon dioxide elimination was found to be adequate for research purposes, and that of VD/VT for clinical purposes. The device is considered to be of value in the operating theatre and intensive care unit, for monitoring, as a guide to ventilatory needs, and for the investigation of the magnitude and causes of increased deadspace.

An automatic sigh feature for animal ventilators.

A device is described that provides a reliable automatic deep breath to an animal being ventilated with a typical laboratory ventilator. The deep breath is provided by closing a solenoid valve in the expiratory tubing causing the animal to inspire two, three, or four consecutive tidal volumes without expiration. The interval between deep breaths is selected to be every 1, 2, 4, 6, 8, or 10 min. Control of this interval is provided by simple integrated circuits. Total parts cost of this device is approximately $90.

Use of side-hole endotracheal tube adapter for tracheal aspiration. A controlled study.

An alternate tracheal aspiration procedure using a side-hole endotracheal adapter was used in conjunction with transcutaneous oxygen (TcPO2) monitoring in 13 mechanically ventilated newborn infants. Decline in TcPO2 during suctioning and drop in neonatal heart rate were both substantially reduced using a procedure designed to preserve mean airway pressure. When compared with the routine procedure of disconnecting the endotracheal tube from the ventilator and suctioning via an end-hold adapter, this approach prevented precipitous and dangerous hypoxemia.