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Biomedical subjects

A Baraka

Publications and source records attributed to A Baraka.

At least 73 records · Page 4Linked to original sources
PubMed1996

Efficacy of the self-inflating bulb in confirming tracheal intubation in the morbidly obese.

BACKGROUND: This study was designed to determine the incidence of false-negative and false-positive results when the self-inflating bulb (SIB) is used to differentiate tracheal from esophageal intubation in morbidly obese patients using two techniques. In technique 1, the SIB is compressed before it is connected to the tube; in technique 2, the SIB is compressed after connection to the tube. METHODS: With institutional review board approval, 54 consenting adult morbidly obese patients (body mass index > 35) undergoing elective surgical procedures were included in the study. After anesthetic induction and muscle relaxation, both the trachea and esophagus were intubated under direct vision with identical cuffed tubes. The efficacy of the SIB in verifying the position of both tubes was tested by a second anesthesiologist. The speed of reinflation was graded as rapid ( < 4 s) or none ( > 4 s), using both techniques. In the case of tracheal intubation, the absence of reinflation was recorded as a false-negative, whereas in cases of esophageal intubation, rapid reinflation was recorded as a false-positive. Identification of tube location by the second anesthesiologist was based on SIB reinflation results from techniques 1 and 2, as well as the presence of a flatuslike sound elicited by technique 2 in esophageally placed tubes. All patients were retested by the SIB after receiving three breaths of 400-500 ml each. In all patients exhibiting false-negative results, six obese patients exhibiting true-positive results, and four nonobese patients exhibiting true-positive results, tracheal responses to the SIB maneuvers were observed directly by a flexible fiberoptic bronchoscope incorporating an airtight system, 15-20 min after mechanical ventilation was instituted. RESULTS: The incidence of false-negative results was initially 30% with technique 1 and 11% with technique 2, but decreased to 4% when technique 2 was used after the delivery of three breaths. The second anesthesiologist initially identified tube location in 92.5% of patients correctly. After the delivery of three breaths, tube location was correctly identified in 96.3% of patients. Fiberoptic bronchoscopic examination of the patients exhibiting false-negative results revealed exaggerated inward bulging of the posterior tracheal membrane during reinflation of the SIB when technique 1 was used. CONCLUSIONS: Contrary to previous investigations in healthy patients, the current study demonstrates a high incidence of false-negative results when the SIB is used to confirm tracheal intubation in morbidly obese patients. If the SIB is used, the technique should include compression of the SIB after connection to the tube and should be used in conjunction with other clinical signs and technical aids. The mechanism of false-negative results in these patients seems to be related to reduction of caliber of airways secondary to a marked decrease in functional residual capacity, and collapse of large airways due to invagination of the posterior tracheal wall when sub-atmospheric pressure is generated by the SIB.

Adolescent↗
PubMed1996

Hazards of nitrous oxide administration in presence of venous air embolism.

Nitrous oxide administration in presence of venous air embolism results in its volume augmentation. The present case report of a 50-year old patient undergoing posterior fossa tumor excision in the sitting position demonstrates the hazards of nitrous oxide in presence of venous air embolism. Administration of 66% nitrous oxide 140 minutes after the incidence of air embolism resulted in a significant decrease of end-tidal carbon dioxide tension, moderate hypotension, and tachycardia, suggesting volume augmentation of the air embolism. The results of our case report are in contrast to that by Shapiro et al who noted that nitrogen washout following administration of 100% oxygen was complete 65 minutes after the occurrence of venous air embolism. Shapiro and colleagues suggest the use of nitrous oxide challenge as a diagnostic aid in deciding when lung excretion of intravascular air is complete. However, our case report implies that nitrogen washout was not complete 140 minutes after venous air embolism incidence. Accordingly, we recommend to stop nitrous oxide administration once air embolism is suspected and to refrain from its re-administration throughout the rest of surgery.

Anesthetics, Inhalation↗
PubMed1995

Effectiveness of the self-inflating bulb for verification of proper placement of the Esophageal Tracheal Combitube.

The esophageal tracheal Combitube (ETC; Sheridan Catheter Corporation, Argyle, NY) is a twin-lumen tube used to establish emergency ventilation. After blind placement, ventilation is performed via the proximal lumen if it is in the esophagus or via the distal lumen if it is in the trachea. This investigation was designed to test the reliability of the self-inflating bulb (SIB) in identifying the location of the ETC and facilitating its proper positioning in anesthetized patients. In Group 1 (n = 26), the ETC was introduced blindly. In Group 2 (n = 20), the tube was placed in the trachea (eight patients) or once in the trachea and once in the esophagus, randomly (12 patients) under direct vision rigid laryngoscopy by the anesthesiologist performing the intubation. In both groups, the efficacy of the SIB in identifying the location of the ETC was tested by a second blinded anesthesiologist. In Group 1, blind insertion of the ETC resulted in esophageal placement in all patients, and in each case was correctly identified. The second anesthesiologist reported no reinflation when the compressed SIB was connected to the distal lumen. When the compressed SIB was connected to the proximal lumen, instantaneous reinflation was observed in 23 patients, delayed reinflation (2-4 s) in two and no reinflation (> 4 s) in one patient. Instantaneous reinflation occurred in these three patients after repositioning of the ETC. In Group 2, the second anesthesiologist correctly identified the location of the ETC in all cases. The results confirm previous findings that blind introduction of the ETC leads to esophageal placement and yields adequate ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

The laryngeal mask airway for fibreoptic bronchoscopy in children.

A size 2 laryngeal mask airway (ID 7 mm) was used for general anaesthesia during fibreoptic bronchoscopy in a six-year-old child. The mask permitted the use of an adult bronchoscope with an external diameter of 5 mm. Throughout bronchoscopy, adequate controlled ventilation could be achieved easily without excessive air leak or airway resistance; the Spo2 was always > 97%, and the end-tidal Pco2 ranged between 3.9-4.5 kPa (30-35 mmHg).

Airway Resistance↗
PubMed1995

The hemodynamic effects of isoflurane before and after sternotomy in patients undergoing coronary artery bypass grafting.

The hemodynamic effects of isoflurane were studied in 30 patients undergoing coronary artery bypass grafting, and receiving high dose of fentanyl (40 micrograms/kg). In 15 patients, isoflurane 2% was administered for ten minutes before sternotomy, while the same concentration of isoflurane was administered in the other 15 patients after sternotomy for the same interval of time. Isoflurane administration before sternotomy produced a significant decrease in cardiac index and mean arterial pressure, without a significant change in systemic vascular resistance or other hemodynamic variables. On the other hand, when isoflurane was used to counteract sternotomy-induced hypertension, it produced a significant decrease of systemic vascular resistance, associated with a significant increase in cardiac index.

Anesthetics, Inhalation↗
PubMed1994

Laparoscopic treatment of hydatid cysts of the liver.

We report for the first time treatment of hydatid cyst of the liver laparoscopically. The patient is a 27-year-old man who presented to our hospital with a 6-week history of recurrent right-upper-quadrant pain with abdominal ultrasound findings compatible with hydatid cyst of the liver. The cyst was approached laparoscopically using the same hydatid asepsis as in open surgery. The cyst was evacuated laparoscopically and marsupialized, and its remaining cavity was packed with omentum. The patient did well postoperatively and was discharged home on the third postoperative day. He had minimal biliary leak that ceased spontaneously on the fifth postoperative day.

Adult↗
PubMed1994

Postoperative respiratory depression following excision of carotid body tumours.

This report is of two adult patients who were scheduled for excision of carotid body tumours. One of the patients had bilateral tumours, while the second had a unilateral tumour. In the first, anaesthesia was maintained by nitrous oxide:oxygen and halothane 1-2%. Postoperatively, the intramuscular injection of meperidine 75 mg resulted in apnoea, cyanosis, and loss of consciousness. In the second, anaesthesia was maintained by nitrous oxide:oxygen, supplemented by fentanyl 2 micrograms.kg-1 and incremental doses of vecuronium. Following complete reversal of neuromuscular block, the patient became wide awake but spontaneous breathing was resumed at a rate of only two to three breaths per minute, and the oxygen saturation as monitored by pulse oximetry decreased to 50%. Naloxone 0.4 mg iv increased the respiratory rate to 14 per minute and the oxygen saturation to 98%. The report suggests that surgical excision of carotid body tumours, whether unilateral or bilateral, can be followed by severe postoperative respiratory depression. The complication may be attributed to opioid administration in the absence of peripheral chemoreceptor drive.

Adult↗