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Biomedical subjects

D Mangar

Publications and source records attributed to D Mangar.

At least 19 recordsLinked to original sources
PubMed1996

Malignant hyperthermia involving the administration of desflurane.

PURPOSE: This report describes an episode of malignant hyperthermia (MH) in a ten year old boy receiving desflurane anaesthesia. CLINICAL FEATURES: Following induction of general endotracheal anaesthesia with thiopentone and succinylcholine, desflurane was administered for maintenance of anaesthesia. Ten minutes after commencing desflurane administration, heart rate and PETCO2 increased to 165 bpm and 50 mmHg, respectively. Initially, the tachycardia was attributed to a sympathetic response secondary to desflurane. Desflurane was discontinued and isoflurane was started. Minute ventilation was increased to decrease PETCO2. Over the next five minutes, temperature increased to 38.4 degrees C as the PETCO2 increased to above 60 mmHg. Venous and arterial blood gases were drawn which showed acidosis and hypercapnia. Temperature and PETCO2 continued to increase, reaching peak values of 41 degrees C and 77 mmHg, respectively. Efforts to cool the patient were made. A total of 220 mg dantrolene sodium was administered iv. Following dantrolene, the temperature increase and acidosis subsided. Heart rate and PETCO2 decreased to 130 bpm and 36 mmHg, respectively. The surgical procedure was expeditiously performed. Postoperatively, in the Paediatric Intensive Care Unit, a dantrolene infusion of 20 mg.hr-1 was administered for 12 hr. The trachea was extubated the following morning. Several days later, the patient underwent another surgical procedure without complications using MH-safe anaesthetics. CONCLUSION: Onset of tachycardia in a patient receiving desflurane may initially be attributed to desflurane-induced sympathetic hyperactivity. This poses a clinical challenge in the diagnosis of MH during desflurane anaesthesia.

Anesthetics, Inhalation↗
PubMed1994

Pneumothorax during laparoscopic Nissen fundoplication.

We present a case of 100% pneumothorax in a 41-yr-old man with a history of gastritis and gastroesophageal reflux scheduled for Nissen fundoplication. The patient was anaesthetized, and insufflation of the abdominal cavity with carbon dioxide was performed uneventfully. There was an increase in the peak inspiratory pressure and wheezing was noted with a decrease in the arterial oxygen saturation to 91%. An obstructive pattern was noted on the end tidal carbon dioxide monitor. The patient also had decreased breath sounds in the left lung field. The endotracheal tube was withdrawn 1.5 cm with equal breath sounds noted in both lung fields, but the wheezing persisted. At the end of the case the trocars were removed and the abdomen was deflated. The arterial oxygen saturation increased to 94% while breathing F1O2 of 1.0. A chest roentgenogram showed a 100% left pneumothorax. A left chest tube was placed with immediate improvement of the arterial oxygen saturation to 100%. We recommend monitoring of arterial oxygen saturation, peak inspiratory pressures, and excursion of the chest for early diagnosis and prompt treatment of pneumothorax during laparoscopic procedures.

Adult↗
PubMed1994

Left bronchial intubation by a single-lumen tube in adults: effects of bevel and curvature.

This study was designed to determine whether left bronchial intubation could be accomplished by reversal of the direction of the bevel or by changing the direction of curvature of a normal tracheal tube. The 60 study patients were divided into three groups. In group 1, the patients were intubated in the usual manner, with bevel to the left and the tube concave anteriorly. In group 2, the normal tracheal tube was rotated 90 degrees counterclockwise during insertion. In group 3, the bevel of the tracheal tube was altered to face the right, with the tube still concave anteriorly. In group 1, all 20 tracheal tubes entered the right primary bronchus. In group 2, 14 tracheal tubes (70%) entered the left primary bronchus. In group 3, 18 tubes entered the right primary bronchus and 2 entered the left. The position of the bevel did not influence the positioning of the tracheal tube in the right or left bronchus. In summary, 90 degrees counterclockwise rotation from the usual position and altering the concavity of the tube to face the left significantly increased the likelihood of intubation of the left primary bronchus.

Bronchi↗
PubMed1994

Acute effects of intravascular absorption of 32% dextran 70 on blood coagulation, electrolytes and arterial blood gas.

Thirty-two percent dextran 70 is used to help visualize the uterine cavity during hysteroscopy and is also used intraperitoneally to prevent adhesions. We measured serum electrolytes, serum osmolarity, hematocrit, arterial blood gas and coagulation profile in 11 patients receiving dextran 70 while undergoing hysteroscopy. Dextran 70 had no significant effect on prothrombin time, partial thromboplastin time, thrombin time, fibrinogen level or serum osmolarity. There was a significant decrease in hematocrit, serum sodium and oxygen tension of arterial blood (PaO2). The decrease in sodium and hematocrit suggested hemodilution. This study demonstrated that 32% dextran 70 had a minimal effect on the majority of laboratory parameters measured.

Absorption↗
PubMed1994

Neural network-based detection of esophageal intubation.

To improve the accuracy of early detection of inadvertent esophageal intubation, we designed, trained, and tested a neural network-based computer system to detect the mechanical differences between lung and esophagogastric ventilation. Ten 25 to 30-kg anesthetized swine were sequentially ventilated with tidal volumes of 9, 12, and 15 mL/kg, using tubes placed in the trachea and in the esophagus, while flow and pressure waveforms were collected for 9-10 breaths. Gas remaining in the stomach was aspirated after each period of gastric ventilation. A computer program identified each mechanical inspiration, extracted the first 37 flow and pressure data points from each record, and normalized them to an equal amplitude. A back-propagation single-hidden-layer neural network was trained to identify the origin of flow and pressure waveforms as tracheal or esophageal. Ten different training and testing groups were assembled. In each group, data from nine subjects were used for training and data from the remaining subjects were used for testing. A total of 291 esophageal and 300 tracheal flow and pressure waveforms were analyzed by the network. The network identified esophageal intubation correctly during the first five breaths of all esophageal recordings. In one subject, the network identified the eighth esophageal breath as tracheal and could not identify three breaths. All tracheal intubations were identified correctly. Flow and pressure "signatures" of pulmonary and gastric ventilation are easily learned by a neural network. Therefore, neural-network recognition of esophageal intubation from flow and pressure signals is possible, and the development of an on-line detector for tracheal tube misplacement seems feasible.

Animals↗
PubMed1993

Catheter-induced pulmonary artery haemorrhage resulting from a pneumothorax.

We present a case of pulmonary artery perforation in a patient who developed a pneumothorax after cardiac surgery. In the process of inserting a chest tube the patient became tachypnoeic, and developed haemoptysis. The trachea was intubated, and right bronchial intubation was performed with persistent bleeding. The pulmonary artery catheter was gently withdrawn and the balloon inflated, with cessation of bleeding. The patient was taken to the operating room, a bronchial blocker was placed in the right lower lobe bronchi, and the pulmonary artery catheter was removed. The bronchial blocker was removed the following day with no bleeding. The aetiology of perforation was secondary to the pneumothorax, which caused a shift of the mediastinum to the right, elevated pulmonary artery pressures, and the distal migration of the catheter through the pulmonary artery. It is recommended that treatment include tracheal intubation, inflation of the pulmonary artery catheter balloon, and the placement of a right lower lobe bronchial blocker.

Aged↗
PubMed1993

Delayed ischaemia of the hand necessitating amputation after radial artery cannulation.

We present a case of ischaemic hand injury in a patient, who had 95% occlusion of both the ulnar and radial arteries, after atraumatic placement of a left radial artery catheter. The presence of cigarette burns on the dorsum of the hand was highly suggestive of vascular compromise. There were no signs of vascular compromise after placement of the arterial line which was removed 24 hr later. Ten days after placement the patient complained of pain with ensuing ischaemic changes resulting in necrosis of the finger tips and eventual amputation of the hand. We recommend using other sites of arterial access such as axillary or superficial temporal artery in patients with severe peripheral vascular disease.

Adult↗
PubMed1993

Pancuronium, vecuronium, and heart rate during anesthesia for aortocoronary bypass operations.

To determine the effects of pancuronium and vecuronium on heart rate, 90 patients scheduled for aortocoronary bypass were randomly assigned to one of three groups (30 patients each) which received vecuronium 100 micrograms[sdot]kg-1, pancuronium 100 micrograms[sdot]kg-1, or a mixture of vecuronium (50 micrograms[sdot]kg-1) and pancuronium (50 micrograms[dot]kg-1) in a double-blind fashion during induction of anesthesia. All patients were premedicated with lorazepam prior to surgery, hence avoiding the effects of scopolamine. Our results showed no significant increase in heart rate from the administration of pancuronium, following administration of this drug the heart rate increased by only four beats per minute. The heart rate was unchanged after the mixture, but decreased by twelve beats per minute after vecuronium (P < 0.05). The heart rate response differed by 16 beats per minute between pancuronium and vecuronium. All patients who received either of the neuromuscular relaxants and who were on beta blockers showed a decrease in heart rate. In this study, the administration of pancuronium after an adequate induction dose of fentanyl did not cause tachycardia. We therefore feel that pancuronium still has a role in cardiac anesthesia, especially as the newer muscle relaxants such as vecuronium, pipecuronium and doxacurium are significantly more expensive.

Aged↗