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Biomedical subjects

M Klain

Publications and source records attributed to M Klain.

At least 37 records · Page 2Linked to original sources
PubMed1984

Tobacco smoking: impairment of experimental flap survival.

The survival rate of experimental flaps as affected by exposure to inhaled tobacco smoke has been investigated in rats subjected to different smoking regimens. A distally based dorsal flap was raised and reattached in each animal. Evaluation of the flaps on postoperative day 8 showed a mean rate of necrosis of 28.5% in 25 control animals, 32.2% in 21 rats postoperatively smoking for 7 days, 41.3% in 18 rats preoperatively smoking for 7 days, and 45.7% in 21 rats smoking for 7 days both before and after the surgical procedure. Histological sections from the lungs of the smoking animals revealed a pattern compatible with mild smoke inhalation injury. Arterial oxygen tensions were lower in the tobacco smoking animals. It is assumed that the multiple effects of tobacco smoking contributed to the impairment of experimental flap survival.

Animals↗
PubMed1984

High-frequency jet ventilation in the postoperative period: a review of 100 patients.

One hundred patients were ventilated with high-frequency jet ventilation (HFJV) during the initial 24-h postoperative period in the surgical and neurosurgical ICUs. Eighty-three were successfully weaned, 2 could not be ventilated adequately with HFJV, and 15 with criteria of acute respiratory failure received HFJV for up to 21 days. A HFJV delivery system consisted of jetting and entrainment systems, both with their own humidification designs. An initial mode of HFJV using 35 psi, jet rate 100 cycle/min and inspiratory time 30% provided a mean PaCO2 of 34 torr in 38 patients studied. A comparison of HFJV without and with a positive end-expiratory pressure (PEEP) of 10 cm H2O indicated a decrease in mean Qsp/Qt from 17% to 13% with decrease in cardiac index (CI) from 3.39 to 2.81 L/min X m2; this effect is similar to PEEP applied to a conventional ventilator. Weaning proved to be simple and comfortable for the patient. In the light of our experience, we believe that HFJV is both feasible and practical for the postoperative patient and should be introduced into routine clinical use.

Adolescent↗
PubMed1984

High-frequency jet ventilation versus intermittent positive-pressure ventilation.

Airway pressures and cardiorespiratory variables were compared for conventional ventilation (CV) and high-frequency jet ventilation (HFJV), at a similar fraction of inspired O2 (FIO2), positive end-expiratory pressure (PEEP) and PaCO2 in 11 ICU patients. For CV and HFJV, respectively, peak (PAP) and mean airway pressures (Paw) were 15.4 and 9.1 mm Hg and 4.4 and 5 mm Hg. Cardiac index (CI) was 2.54 and 2.60 L/min X m2, total systemic vascular resistance index (SVRI) 2846 and 2923 dyne X sec/cm5 X m2, PaO2 207 and 149 torr, and Qsp/Qt 7% and 11%. HFJV decreased significantly PAP and was less likely to produce pulmonary barotrauma. Cardiac indices were not different, indicating that this variable may be affected by Paw. HFJV neither increased nor decreased CI at similar PEEP and PaCO2 as compared to CV. The decrease in PaO2 and increase in Qsp/Qt may be due to small inspired gas volumes potentiating microatelectasis. On the basis of this study, we recommend initiating HFJV at FIO2 of 0.9 and PEEP of 5 cm H2O, and monitoring both PAP and Paw.

Aged↗
PubMed1984

High-frequency jet ventilation and tracheobronchial suctioning.

Oxygenation and ventilation were assessed in 15 postoperative patients before, immediately after, and 3 min after 15 sec of tracheobronchial suctioning in the presence or in the absence of high-frequency jet ventilation (HFJV). When HFJV was continued during suctioning, the mean PaO2 decrease was only 15 +/- 9 torr, compared to a 90 +/- 16 torr decrease when HFJV was discontinued. This difference demonstrates that continuation of HFJV during tracheobronchial suctioning prevents a decrease in PaO2.

Bronchi↗
PubMed1983

Transtracheal high frequency jet ventilation prevents aspiration.

Aspiration is a potentially fatal complication of artificial ventilation. A cuffed tube is generally used now to prevent aspiration; however, it may lead to serious complications and has several disadvantages. High frequency jet ventilation (HFJV) is an innovative technique to prevent aspiration. The trachea of 6 anesthetized, paralyzed dogs was exposed and a catheter for jet ventilation introduced between the 1st and 2nd tracheal ring. Another catheter was used for measuring intratracheal pressure. An endoscope was inserted into the trachea about 2 inches lower down and directed upwards to give a view of the vocal cords from below. A mixture of saliva, saline, and cardiogreen was introduced into the mouth so as to form a pool. When observation confirmed that HFJV prevents aspiration at frequencies of 100/min and ratios of inspiration/expiration (I:E) equalling 1:1, observations were repeated at I:E, 1:2 and 1:3 and at rates of 60/min and 200/min. The depth of the pool was gradually increased to between 2 and 31/4 inches and observations were repeated. Endoscopy alone was used in 4 animals and endoscopic film in 2 to evaluate the efficacy of HFJV. The results showed convincingly that: (1) HFJV can prevent fluid from entering the larynx from above; (2) this effect is unreliable when the frequency is decreased to 60/min or inspiration becomes shorter than 33% of the cycle; (3) intratracheal end-expiratory pressures show values slightly higher than the fluid level above the cords; and (4) the cords are separated and the gas mixture bubbles through the fluid. We conclude that (a) valve mechanisms cannot account for our observations; and (b) at rates above 60/min and with duration of expiration of 66% or less, HFJV will prevent aspiration by causing a continuous gas flow outward through the larynx. This is associated with a low continuous positive airway pressure and excellent blood gases.

Animals↗
PubMed1983

Long-term high frequency jet ventilation in a 3-year-old child.

Successful management of a large bronchopleural fistula in a 3-yr-old child with high frequency jet ventilation (HFJV) is described. Respiratory insufficiency in the child occurred secondary to hemophilus influenza pneumonia. After 7 days of conventional ventilatory support, a bronchopleural fistula occurred with massive lung collapse and subcutaneous and mediastinal emphysema. The child was ventilated with a high frequency jet ventilator for 37 days with resulting healing of the fistula. During ventilatory support with HFJV, no sedation or muscle relaxants were needed. Two problem areas in long-term support in children were discussed, namely, partial tube obstruction because of thick secretion and the need for proper humidification. A significant advantage of HFJV was the ability to superimpose it on spontaneous breathing with elimination of sedation or muscle relaxants.

Blood Gas Analysis↗
PubMed1983

Renal function and renin secretion during high frequency jet ventilation at varying levels of airway pressure.

The effect of positive end-expiratory pressure (PEEP) on plasma renin activity (PRA), renal function, and cardiovascular (CV) hemodynamics during high frequency jet ventilation (HFJV) was observed in 7 patients. The addition of PEEP during HFJV increased PRA while decreasing stroke index (SI) and cardiac index (CI). These changes were associated with decreased urinary flow, creatinine clearance, and fractional excretion of sodium. In contrast, HFJV at zero end-expiratory pressure (ZEEP) maintained normal PRA, renal function, and CV hemodynamics. The authors conclude that the alteration of renal function during HFJV is a function of airway pressure rather than the effects of the ventilatory frequency. The deterioration of renal function may have been due to changes in PRA or CV dynamics.

Adult↗
PubMed1982

High-frequency jet ventilation in oral and maxillofacial surgery.

The oral and maxillofacial surgeon faces many situations in which maintenance of the patient's airway can be a problem. Facial trauma, severe infection, and trismus all can compromise the airway and pose a dangerous situation. The use of high-frequency jet ventilation (HFJV) via transtracheal puncture offers excellent airway protection with minimal patients discomfort prior to induction of anesthesia. The use of a large, cuffed endotracheal tube for blind awake nasal intubation, or in conjunction with tracheostomy, can be eliminated in many situations. HFJV offers minimal trauma to nasal passages and larynx while preventing aspiration. During emergence, discomfort is reduced to a minimum, and the patient can communicate verbally. These same advantages apply to patients who receive outpatient oral surgery. Therefore, in the choice of an anesthetic technique, HFJV should be a definite consideration.

Adult↗
PubMed1982

Comparison of high frequency jet ventilation to conventional ventilation during severe acute respiratory failure in humans.

High frequency jet ventilation (HFJV) was compared to conventional (high tidal volume, low frequency) ventilation in 9 patients with acute respiratory failure (ARF). Alveolar ventilation was comparable or lower with HFJV in all but one case. When comparisons were made at the same concentration of oxygen and level of PEEP, no consistent change in arterial oxygenation (PaO2) was found. In one case, it was possible to increase PaO2 during HFJV by additional increases in PEEP without elevation in peak airway pressure (AWP) compared to conventional ventilation (CV). At the same level of PEEP, peak AWP was lower during HFJV, except in 1 patient with bronchospasm. Cardiac output did not differ significantly between the 2 ventilation systems, except in the same patient with bronchospasm. HFJV may be useful in acute respiratory failure when peak AWP during CV limits effective use of mechanical ventilation for gas exchange. Patients with significantly elevated airway resistance may be an exception. Improvement in PaO2 will usually depend on increases in PEEP.

Acute Disease↗
PubMed1982

Comparison of venous admixture during high-frequency ventilation and conventional ventilation in oleic acid-induced pulmonary edema in dogs.

High-frequency jet ventilation (HFJV) was compared with conventional ventilation ventilation during oleic acid-induced pulmonary edema in dogs. HFJV, when combined with positive end-expiratory pressure (PEEP), returned arterial PO2 (PAO2) and venous admixture to preoleic acid levels, even with tidal volumes as low as 4.8 ml/kg and rates of 300 min-1. When HFJV was compared with conventional (low-frequency, high tidal volume) ventilation at the same Flo2 and level of PEEP, Pao2 was lower and venous admixture higher with HFJV. However, venous admixture was lower with HFJV when comparisons were made at the same peak airway pressure, because of a higher level of PEEP compared with conventional ventilation. At each level of PEEP, cardiac and stroke indices were not different between the two methods of ventilation. The ability to eliminate CO2 with lower peak airway pressures or to increase PEEP without further increases in peak airway pressure are the primary advantages of HFJV during severe lung injury. Oxygenation is as efficient during HFJV as during conventional ventilation in this model of pulmonary edema when comparisons are made at the same peak airway pressure, but less efficient at the same PEEP.

Airway Resistance↗
PubMed1981

High-frequency jet ventilation during the treatment of acute fulminant pulmonary edema.

High-frequency jet ventilation (HFJV) was used during the treatment of fulminant pulmonary edema in a 45-year-old man so that toxic levels of oxygen could be avoided when conventional methods of ventilation in combination with high levels of PEEP (20 cm H2O) were unsuccessful in raising PaO2. On each of four occasions, HFJV resulted in improved arterial oxygenation when compared with conventional modes.

Acute Disease↗
PubMed1980

Limits of high frequency percutaneous transtracheal jet ventilation using a fluidic logic controlled ventilator.

A study was undertaken on dogs to find the limit of carbon dioxide exchange with high frequency jet ventilation using a fluidic logic controlled oxygen jet ventilator. Fifteen dogs were ventilated through a transtracheal catheter at respiratory rates up to 600 per minute. The following were recorded: aortic, pulmonary artery, pulmonary arterial wedge, and central venous blood pressures; intratracheal pressure, electrocardiogram; inspiratory and expiratory time of the jet; arterial and central venous blood gases; intermittent cardiac output. Normal gas exchange was found up to a respiratory rate of 400 per minute with low tidal volume and low intratracheal pressures. There were no adverse circulatory effects up to a rate of 400 per minute. At rates of 500 and 600 per minute, cardiac contractility was unaffected, but a decreased heart rate and increased peripheral resistance produced a fall in cardiac output. There was no interference with the resumption of spontaneous ventilation during weaning. In a control series of five dogs, apnoeic oxygenation was used. The PaCO2 was allowed to reach 15.96 kPa (120 torr). High frequency jet ventilation was then started at a rate of 600 per minute and decreased in increments to 100 per minute. Arterial blood gases were continuously recorded through an intra-arterial catheter connected to a mass spectrometer. The PaCO2 gradually declined to normal levels as the rate decreased.

Animals↗