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An individual who has sustained either irreversible cessation of circulatory and respiratory functions, or irreversible cessation of all functions of the entire brain, including the brainstem is dead. A person is not dead unless his brain is dead. The time-honored criteria of stoppage of the heartbeat in circulation are indicative of death only when they persist long enough for the brain to die. Brain death does not require every brain cell to be nonviable but the criteria require an irreversible loss of neurologic function of a patient interminably supported by a mechanical respirator. For death to be diagnosed by an irreversible cessation of circulation and respiration an absence of circulation should be observed for at least two but no more than five minutes. Irreversibility is determined by a "permanent" loss of function meaning that the function will not be restored 1) because it will neither return spontaneously, nor 2) will it return as a result of medical intervention because physicians have decided not to attempt resuscitation.

No satisfactory mechanical respirator existed before 1929, when Philip Drinker and Louis Shaw described an apparatus of their own design. This machine was in the form of a cylindrical tank enclosing the patient's body and chest, leaving the head outside the chamber under atmospheric pressure. Air pumps, later a bellows, raised and lowered pressure within the tank to assume the entire work of breathing. Popularly named the iron lung, the Drinker respirator supported thousands of patients afflicted with respiratory paralysis during the polio era. It was being superseded by positive-pressure airway ventilators just as the polio era came to a close. Today the Drinker respirator has disappeared virtually without a trace. Although its disadvantage was its cumbersome size, we must concede that it supported patients over the long term with fewer complications than do the respirators of today.

The author discusses the problems of euthanasia with particular reference to the case of Karen Quinlan, whose parents sought to obtain judicial authorization to withdraw the support of a mechanical respirator and allow the girl ‘to die with grace and dignity’.

Forty infants with severe idiopathic respiratory distress syndrome have been treated with intermittent mask and bag therapy as an alternative to the mechanical respirator. Twenty-four of the infants (60 per cent) survived. This survival rate compares favorably with that of infants treated with continuous respirator therapy, and pulmonary complications appear to be minimal. The procedure requires simple equipment and is easily taught to nurses and physicians. Mask and bag therapy appears to be an easily adapted and relatively safe alternative to the respirator in infants with the idiopathic respiratory distress syndrome.

A mechanical respirator with synchronized respiratory partitioning valve for guinea pigs is described. This apparatus is used for the separate determination of dust retention in the upper respiratory tract and deep lung spaces. The partitioning valve separates the exhaled air into three fractions beginning with the earliest portion of upper respiratory air and continuing to the terminal fraction of deep lung air. The same volumetric fractions from successive exhalations are collected over a test period of any practical duration. In principle, the apparatus is similar to one previously described (Rev. Sci. Instr. 22, 81, 1951) for the study of dust retention in human lungs.

Preliminary studies are presented concerning a new approach to artificial control of mechanical respirators. The experimental and clinical results of this method have been gratifying. The development of the muscle potential amplifier as used to control the respirators has opened up other fields of endeavor. Some of the more important applications now under investigation are: (1) The adaption to control a mechanical respirator for premature and newborn infants (Fig. 7). This is being evaluated in prematures and infants with hyalin membrane disease. (2) For Internal stabilization of a flail chest or one exhibiting paradoxical motion. (3) To control an extracardiac stimulator in cases of complete heart block by utilizing the auricular p wave to trigger such a device. (4) To control the contraction of the McKibbon artificial muscle. The respirator as now used appears to maintain more normal respiratory function than previous units have been capable of doing. We definitely feel that the control of mechanical insufflators by the patient's own biochemical and physiological needs is in every instance desirable if practical.

There is a need for an effective means of controlling smoke inhalation among forest fire fighters. It then seems logical that the bulk of the detrimental effects of the smoke on the fire fighter could be avoided by the use of a purely mechanical respirator.

Summary 1. A brief report of the recordedcases of poliomyelitis in infancy has been presented. 2. The case of an 11-week-old infant with bulbospinal poliomyelitis, who required both a tracheotomy and a mechanical respirator, has been discussed. 3. This case also demonstrated thatpatients who could not handle their oropharyngeal secretions, or could not swallow, should not be placed into a mechanical respirator before tracheotomy was performed.

The average operating room makes no provision for mechanically maintaining artificial respiration in patients during operation. In the absence of adequate pulmonary ventilation, other resuscitative measures are generally of little value in advanced respiratory or cardiac failure.1 Such accidents are sufficiently common in the operating room to warrant a carefully organized plan for resuscitation and especially to include in this plan a method of artificial respiration for the surgical patient.During the past 2 years a mechanical respirator, of a type commonly used in physiological laboratories for the intermittent insufflation of compressed air down a tracheal catheter, has been kept available on the operating floors of the University Hospitals. During this period of time the respirator has been successfully used in 4 cases of acute cardio-respiratory failure and might have been successful in several other cases if the artificial respiration could have been instituted more promptly. This fact aroused the ...

Thirty-four adult, splenectomized mongrel dogs weighing from 14.5 to 26.8 kg. were anesthetized with nembutal and ventilated with ambient air by a mechanical respirator. Arterial hematocrits, systemic arterial pressures, and cardiac outputs (cardiogreen indicator-dilution methods) were recorded in the prebleed and postbleed periods. After recording initial blood volumes (measured with I13i labeled albumin) all dogs were heparinized (1 to 2 mg./kg. body weight) and were bled 30 per cent of their measured blood volume in less than forty-five seconds through bilateral carotid cannulas. Fourteen dogs were placed in a pressure chamber (Fig. 1) and immediately postbleed, the chamber was sealed, and the chamber pressure was rapidly increased to and maintained at 25 mm. Hg for two hours and then slowly decompressed over the next fifteen to thirty minutes. The respirator was placed inside the pressure chamber and a sufficient flow of compressed air was maintained into the chamber and through an exit valve in order to prevent an accumulation of carbon dioxide and a decrease of oxygen inside the chamber. RESULTS

A 16-year-old man with occipito-cervical dislocation and survival was treated at Rancho Los Amigos Medical Center. The patient had ligamentous instability between the occiput and the cervical spine. His neurologic level was complete at the C1 level, and he was dependent on a mechanical respirator. Sternocleidomastoid and other neck musculature were not functional. A fusion of the occiput to cervical spine and cervical spine to thoracic spine was performed to obviate the need for external neck support. The patient went on to fuse and is now independently mobile with a tongue-switch driven wheelchair with a respirator trailer 2 years after injury. The patient has no need for external support as a result of his fusion.

A system for the continuous monitoring of gas exchange as well as 14CO2 from metabolic studies is described. The analyzer incorporates modifications over previously published systems. These modifications include accurate control of analyzer pressure for stable baselines during the long periods of measurement, accurate control of temperature, the measurement of oxygen consumption during high oxygen patient therapy, the measurement of oxygen consumption of patients on a mechanical respirator, and describes a unique flux system to calibrate the analyzer detectors. The closed system provides expired breath data for O2, CO2, and 14CO2 on critically ill patients for long periods of time without stressing the patient and without using a face mask or mouthpiece. These data allow for the calculation of daily energy expenditures of hypermetabolic patients and for the assessment of various metabolic responses with 14C substrates.

THE USE of a plastic adhesive, methyl 2-cyanoacrylate (Eastman 910 Monomer) has been investigated in many laboratories. Studies have included its application to the gastrointestinal tract, 1 blood vessels and heart, 2-5 liver, 6 and lung. 7,8 In general, this material has been used successfully in each of these anatomic areas. Results have indicated that it is self-sterilizing, is accompanied by minimal foreign body reaction, and forms a strong seal when used for anastomoses of luminal structures. The present investigation was undertaken further to evaluate its use in cardiovascular surgery. Methods and Materials Mongrel dogs weighing 15 to 30 kg were anesthetized using sodium pentobarbital administered intravenously. Animals undergoing thoracic operations had endotracheal intubation and were attached to a mechanical respirator during surgery. Anticoagulants and antibiotics were not used postoperatively. Four groups of dogs were prepared. Group 1. —In ten animals the chest was entered through a lateral incision over

An apparatus is described for the partitioning of exhaled air into seven separate fractions beginning with the earliest portion of upper respiratory air and continuing to the terminal fraction of deep‐lung air. The same volumetric fractions from successive exhalations are collected over a test period of any practical duration. This apparatus has been employed for the study of lung retention of inhaled particulate matter with particular reference to the separate estimate of upper respiratory retention and penetration to and deposition of particulate matter in alveolar spaces. The apparatus is employed with a mechanical respirator of the Drinker type, which fixes the respiratory pattern at any desired frequency and tidal volume.

The canister from a U. S. Navy Standard Oxygen Closed Circuit Breathing Apparatus was modified to accomodate reduced loads of pellet Baralyme. Polystyrene rods, inserted longitudinally, were used to occupy the vacated intracanister space. In a controlled laboratory environment, and with a mechanical respirator for the simulation of respiratory and CO2 production values, the relationships between absorbent weight and swimming duration were determined. A number of canister design and absorbent function characteristics were concurrently studied.

Top of pageAbstract Permanent dependence on a mechanical respirator, even when associated with severe or total locomotor paralysis, does not preclude discharge from hospital to domiciliary life, provided certain equipment and facilities are provided. Much can be learnt from cases of lower motor neuron paralysis of the respiratory muscles— usually caused by poliomyelitis and associated with severe locomotor disability— who have successfully established themselves at home and, step by step, overcome the difficulties created by their respiratory and locomotor paralyses. The equipment and facilities which they need fall into three categories: (a) Respiratory. They need not only the necessary basic equipment of respirator and, where necessary, sucker, but also a reliable system to ensure that errors in electricity supply, in the machines themselves, and in the connections and other accessories are easily, promptly and, if possible, automatically corrected. Provision should also be made for mobility of the patient and his equipment, so that he is not permanently confined to one room in one house. Adequate arrangements must be made for servicing the equipment at regular intervals and for rectifying faults. (b) 'Care'. Wise selection of equipment and techniques for routine nursing and daily living activities greatly reduces the time and effort spent on them. (c) Occupational and Recreational. These enable the patient and his family to live to maximum capacity within the limits of the physical disability: they may enable the patient himself to earn part or all of the necessary family income. The importance of this final stage of rehabilitation in the management of the severely paralysed is stressed.

Thirty-three patients who required short-term postoperative mechanical ventilatory support were studied to compare different criteria established to initiate weaning from mechanical ventilation. Intermittent mandatory ventilation criteria (i.e., decreasing mechanical respirator rate as long as the arterial (pHa) remains above 7.35) and conventional criteria (ie, vital capacity greater than 15 ml/kg and peak negative pressure greater than 20 cm H2O) were compared to determine which would more rapidly predict a patient's ability to sustain total spontaneous respiration. All patients were eventually weaned from mechanical ventilation and had their tracheas extubated. Twenty-one patients maintained a pHa of greater than 7.35 during total spontaneous ventilation before they would, or could, meet conventional criteria for initiating a trial of spontaneous respiration (P less than .001). Seven patients simultaneously met both criteria for maintaining total spontaneous ventilation and the remaining five patients met conventional criteria before intermittent mandatory ventilation criteria. In the latter group, the pHa decreased below 7.35 during spontaneous respiration but in only one patient did it fall below 7.30. Our findings suggest that a patient's ability to maintain a pHa of greater than 7.35 while decreasing the frequency of mechanical ventilator breaths is more accurate than peak negative pressure and vital capacity for predicting ability to sustan adequate spontaneous respiration.

In spite of the continued appearance of scientific evidence of the potential danger of any form of artificial respiration in the newborn infant, this type of therapy still seems to be used a good deal. One writer described the mechanics1that might operate to produce alveolar dilatation when increased pressure is employed to overcome atelectasis. Another author2recently showed sections of lung from a newborn infant who had received artificial respiration. There were areas of atelectasis adjacent to dilated alveoli and rupture of dilated terminal bronchioles allowing escape of air into the interstitial tissues, producing a dissecting emphysema; however, the same picture has been seen in babies who had not received any form of artificial respiration. This would imply that this damage could occur as the result of the patient's own efforts to inflate his lungs. In these cases, it is obvious that any measure that is employed

• Barbiturate poisoning was treated in 243 patients, of whom 160 were comatose on admission to the hospital and 18 required mechanical respirator. The state of the reflexes was at times a confusing criterion of the depth of poisoning. The immediate danger was generally respiratory; the patient's airway was cleared scrupulously, and every step taken to insure adequate intake of oxygen. The circulatory management, in deeply comatose patients, included the starting of venoclysis at the time of admission to provide an immediate route if plasma expanders or vasopressor drugs became necessary. The four patients who were not saved all proved to have serious underlying medical problems in addition to the barbiturate poisoning. Their histories are given with four others to illustrate various principles of treatment. Hemodialysis used in one of these cases removed 890 mg. of barbiturates from the circulation of a deeply comatose patient who made a complete recovery. The use of analeptic drugs and electrical stimulation afforded little additional help and did not provide an adequate substitute for the direct physiological treatment of depressed respiration or circulation.