Aspiration Of Stomach Contents Research Articles

The laryngeal mask airway

The laryngeal mask airway (LMA) is a new concept in airway management. A miniature inflatable mask is positioned in the hypopharynx, forming a low-pressure seal around the laryngeal inlet. The mask is attached via a tube to the breathing circuit. It is inserted after induction of anesthesia without the need for muscle relaxants or laryngoscopy. The LMA can be used to facilitate both spontaneous and controlled ventilation in adults and children. The LMA has been used for a wide variety, of surgical procedures but is probably best suited to short procedures, especially if a light general anesthetic is used in combination with a regional technique. It may be particularly useful in outpatient anesthesia, as it avoids the need for intubation or muscle relaxants. It can be used as an alternative to mask anesthesia or when (in endotracheal tube would have been inserted to allow surgical access. It has been used successfully in cases of difficult or failed intubation, although its role here needs further appraisal. It does not protect against aspiration of stomach contents and should not be used when aspiration is a risk. Controversy exists regarding its use to facilitate positive-pressure ventilation (PPV) due to concern that gases under pressure may be forced into the stomach and predispose the patient to regurgitation. It may be more difficult to use in children. It is now widely used in the United Kingdom; however, it is not yet available for sale in the U.S. It has already had a major effect on practice in Britain and has the potential to do the same in the United States.

Immobilisation of southern elephant seals and leopard seals with cyclohexamine anaesthetics and xylazine

Ketamine and xylazine were given to 55 southern elephant seals (Mirounga leonina) for stomach lavaging, and to three leopard seals (Hydrurga leptonyx). The elephant seals showed prolonged apnoea and two of them died owing to aspiration of stomach contents. Two of the leopard seals died from unknown causes. Tiletamine and zolazepam were given to five elephant seals and one leopard seal. Two of the elephant seals and the leopard seal died from unknown causes. Xylazine alone was administered to 34 leopard seals. Sedation was poor at low dose rates (less than 1.7 mg/kg) but four of the seals given higher dose rates died owing to the aspiration of stomach contents.

Surfactant abnormality and the sudden infant death syndrome--a primary or secondary phenomenon?

A prospective study of 46 infant deaths occurring between 3 and 100 weeks of age was performed and comprised a structured necropsy followed by collection of lung washings for surfactant phospholipid analysis and samples for microbiological examination. Of the 46 infants studied, 23 died from sudden infant death syndrome (SIDS) alone; SIDS was the cause of death in a further 12 but there were additional clinical or pathological findings insufficient in themselves to account for the death ('SIDS-plus'). In 11 there were other causes of death ('non-SIDS'). The lung washings from infants dying from SIDS had significantly lower concentrations of phosphatidylcholine and a significantly lower palmitate content in the phosphatidylcholine. There was no association between surfactant phospholipid abnormality and the presence of recognised pathogens, histological evidence of pulmonary inflammation, aspiration of stomach contents, age at death, sex, and death-postmortem interval. There were, however, lower concentrations of phosphatidylcholine and phosphatidylcholine palmitate content in infants colonised by organisms with reported phospholipase A2 activity.

Pulmonary Aspiration???Effects of Volume and pH in the Rat

To evaluate the effect of volume of aspirates with different pHs on mortality associated with pulmonary aspiration, hydrochloric acid solutions were injected into the tracheas of 336 Sprague-Dawley rats. The rats were divided randomly into 33 groups, were observed for 96 hr after aspiration, and were not resuscitated. Deaths were divided into two groups: early, less than 30 min after aspiration, and late, greater than 4 hr after aspiration. Late deaths, accounting for 22% of all fatalities, occurred exclusively in animals aspirating solutions with a pH less than 2.5. These late deaths indicated progressive lung damage as opposed to acute cardiorespiratory failure, which early deaths suggested. Low volume pulmonary aspirates (0.3 ml/kg) with extremely low pH (1.0) resulted in a high mortality rate (90%). Conversely, higher volume pulmonary aspirates (1.0-2.0 ml/kg) with a higher pH (greater than or equal to 1.8) resulted in a low mortality rate (14%). These data demonstrate an important interaction between pH and volume of aspirates: even low volumes have a high mortality rate if pH is very low, whereas if gastric fluid is effectively buffered, then much higher volumes than previously thought can be tolerated. This suggests that the routine use of nonparticulate antacids may be indicated in patients at risk from aspiration of stomach contents and should not be withheld because of concern of increasing gastric volume.

Estimated lethal ethanol concentrations in relation to age, aspiration, and drugs.

In 98 deaths certified to be due to accidental alcohol poisoning, maximum antemortal blood ethanol concentrations were estimated as the sum of postmortal concentration and the product of blood ethanol elimination rate (0.258 g/liter/hr) and the time interval between the discontinuation of drinking and death. The estimated mean maximum concentration (g/liter) was 4.63 for uncomplicated cases, 4.26 for cases with heart disease, 3.98 for cases in which aspiration of stomach contents had contributed to death, 3.59 for ethanol-barbiturate poisonings, and 3.11 for combinations of ethanol and other psychotropic drugs. The mean for this last group was significantly lower than that for the first or the second group (p less than .001). The mean concentration for ethanol-barbiturate poisonings was signicantly lower than the mean for the uncomplicated cases (p = .01). In the two first groups combined, the higher the age, the lower the ethanol concentration (r = -.27; p = .02). Likewise, the postmortal blood ethanol concentration correlated negatively with age (r = -.26; p = .02), after controlling for the time interval. The lethal ethanol concentration for the aged seems to be lower than that for young people. A possible explanation for this phenomenon is the loss of ethanol tolerance.

AN AUTOPSY CASE OF AMNIOTIC FLUID EMBOLISM

A 40-year-old para II, gravida IV entered the hospital in 37 pregnant weeks. She was in mild labor and at the cervix was dilated three finger's breadth, but the membrane was not ruptured. The next morning the labor became weak, so she was given Atonin 0 5 units with glucose. At 15 minutes after medication, she suddenly became in agony. She delivered an 3, 730g living female infant (forceps delivery). Plasma, glucose, blood, and oxygen were administered, but the patient died. The final clinical diagnosis was shock of unknown origin.Macroscopically, no gross findings were noted except shock kidneys, aspiration of stomach contents and generalized passive congestion of all organs.Microscopically, the final diagnosis was pulmonary embolism by amniotic fluid and decidua.The majority of the pulmonary arteries, arterioles, and capillaries contained amniotic fluid components -epithelial squamae, fat, mucus, and lanugo hairs. Aggregation of leukocytes, platelet-and fibrin thrombi were also present in the vascular lumina. Decidual emboli were found not only in the alveolar spaces, but also in the vascular lumina.

Management of Respiratory Failure-Reply

In Reply.— The use of negative-pressure breathing devices has declined since the advent of reliable positive-pressure breathing machines. However, there certainly are clinical situations in which devices such as the iron lung, cuirass respirator, or rocking bed might be indicated. Caution must be exercised when using these devices just as with any other treatment regimen. Secretions or upper airway obstruction can be a serious problem in patients with swallowing difficulties. If the disease process involves the cranial nerves and muscles concerned with deglutition and phonation, then these types of respirators would be contraindicated in the absence of a protected airway until sufficient function had returned for the patient to protect his own airway. Gastrointestinal function should be intact, as aspiration of stomach contents can be disastrous in paralyzed patients. Also, nursing care, so important to the well-being of these patients, can be compromised when more cumbersome breathing devices are used.

Respiratory Aspiration of Stomach Contents

The aspiration of stomach contents is a common clinical problem of concern to all physicians. Its consequences are varied, depending on the amount and distribution of the aspirate, its pH, and the presence or absence of food, particulate matter, and bacteria. Because multiple factors are involved, aspiration of stomach contents can lead to several distinct syndromes of pulmonary injury, all of which unfortunately have been labeled "aspiration pneumonitis." We review the pathophysiology of each of these syndromes and discuss important diagnostic and therapeutic consequences.

Fasting volume and acidity of stomach contents associated with gastrointestinal symptoms.

Acid aspiration in an important cause of anaesthetic mortality. 430 patients referred for gastric analysis were reviewed. According to observations made at endoscopy, patients were divided into 4 groups--no abnormality, oesophagitis/gastritis, gastric ulcers and duodenal ulcers. The volume of gastric juice varied from 0 to 400 ml, and the pH from 0-8 to 8. The percentage of patients with overnight fasting gastric volume over 25 ml and a pH of less than 2-5 was disturbingly high in all groups: controls 38-5%, oesophagitis/gastritis 51-2%, gastric ulcers 40-0%, duodenal ulcers 73-3%. This last figure is significantly greater than the group with no detectable abnormality. These results indicated that the stomach of a fasting patient often contains sufficient volume of acid gastric juice to place the subject at risk from acid aspiration during anaesthesia. Antacid therapy in all these patients seems imperative and consideration should also be given to preoperative gastric aspiration before induction of general anaesthesia.

Operating room fatalities.

The obstetrician-gynecologist has a new interest in operating and delivery room fatalities, particularly the increasing deaths due to cardiac arrest and aspiration of stomach contents. The inability to prepare some patients adequately for obstetric anesthesia is a frequent handicap. Hasty induction of anesthesia, incomplete preanesthetic medication, and a full stomach are common in delivery rooms. Inexperienced personnel and inadequate equipment add to the anesthetic risk. Fetal death can also occur or begin with accidents of anesthesia. Improvement in resuscitation of the newborn infant is being realized. The anesthesiologist and physiologist are contributors to this advance. The pathologist can aid by helping us to understand better our failures.

The routine use of lumbar epidural anaesthesia in obstetrics: a clinical review of 9,532 cases.

A report is given of an attempt by the anaesthetic staff of the New Mount Sinai Hospital, Toronto, to evaluate lumbar epidural anaesthesia as a routine anaesthetic in obstetrics. This was done primarily in order to eliminate the threat of maternal mortality through the aspiration of stomach contents. To anaesthetize all obstetrical patients in this manner it was necessary to obtain the full co-operation of the entire obstetrical, anaesthetic, and nursing staffs. It was also necessary to modify the technique of lumbar epidural anaesthesia so that the procedure takes only about three minutes. Surgical scrub of the hands and the donning of a sterile gown have been omitted from the technique, with no evidence of infection in the reported 9,532 obstetrical cases and 5,091 surgical cases. The classically dreaded complication of total spinal anaesthesia occurred four times or 0.42 per cent, and that of convulsions occurred six times or 0.63 per cent. All cases responded to therapy without apparent harm to mother or infant. Lesser complications occurred infrequently and have been discussed in the paper. There were no anaesthetic deaths in this series. Labour is apparently not slowed by epidural anaesthesia and dilatation of the cervix seems to be hastened.

Aspiration of Stomach Contents during Anaesthesia

Aspiration of Stomach Contents during Anaesthesia

Acute pulmonary edema due to aspiration of gastric juice.

ACUTE PULMONARY EDEMA DUE TO ASPIRATION OF GASTRIC JUICE Regurgitation and aspiration of stomach contents may cause serious complications in old and infirm patients, in those who are unconscious, regardless of the cause, and in those suffering from some abnormality of deglutition. Suffocation incident to massive aspiration may lead to acute asphyxial death. If the amount aspirated has been smaller, pulmonary abscesses, bronchiectasis, pneumonia or atelectasis may result. These are well recognized complications. One that is relatively unrecognized is chemical pneumonitis from aspiration of gastric juice per se without other foreign material.1 Symptoms appear after a latent period of several . . .

Spontaneous Rupture of the Esophagus

Spontaneous rupture of the esophagus is due to an increase in intraesophageal pressure greater than the tensile strength of the esophagus. Increased intraesophageal pressure is due to the transmission of increased intraabdominal pressure by the stomach contents through the cardia into the esophagus. Rupture is made more likely by distention of the stomach with food or fluid and by obstruction of the espohagus. Obstruction is usually physiological, produced by the complex anatomical makeup of the esophagus and by incoordination of the complex vomiting reflex. Esophagitis, simple ulcer of the esophagus and esophagomalacia weaken the esophagus and so predispose to rupture. Rupture is seen chiefly in association with vomiting and/or retching, alcoholism and diseases of the central nervous system. The linear tear is in the lower third of the esophagus and leads to the rapid development of mediastinitis and/or hydropneumothorax. The 70 per cent mortality in the first 24 hours is due to the violence of the mediastinitis and pleuritis and to the interference with cardio-respiratory function from mechanical compression. In the usual case, a middle aged male, chronic alcoholic, frequently with chronic dyspepsia, during vomiting and/or retching after recent overindulgence in food or alcohol had sudden onset of chest pain, collapse, respiratory distress, upper abdominal rigidity and later subcutaneous emphysema. In the post craniotomy patients vomiting of blood during recovery from anesthesia occurs; consciousness is lost; and there is progressive restlessness, cyanosis, dyspnea with increasing temperature, pulse and respiratory rates. Definite diagnosis is possible by radiologically observing the passage of radio-opaque media through the rent into the mediastinal and pleural spaces or by aspiration of stomach contents from the pleural space. Mediastinal emphysema, rapidly accumulating hydrothorax, and a retrocardiac air bubble and fluid level are suggestive radiologic findings. In the early cases prompt transpleural repair of the rent is the treatment of choice. In the remainder drainage of the mediastinal and pleural spaces is indicated. The most important of the supportive measures are the decompression of any tension pneumothorax or high pressure mediastinal emphysema, and the use of antibiotic therapy. The various surgical procedures used in the 13 survivors are discussed. Two case reports are given.

The Aspiration of Stomach Contents into the Lungs During Obstetric Anesthesia

The Aspiration of Stomach Contents into the Lungs During Obstetric Anesthesia

The Aspiration of Stomach Contents into the Lungs During Obstetric Anesthesia

The Aspiration of Stomach Contents into the Lungs During Obstetric Anesthesia

The Aspiration of Stomach Contents in Artifical Respiration

The Aspiration of Stomach Contents in Artifical Respiration