Modified interface between pediatric ventilator and Ayre's T-piece for use in neonates.

The lowest tidal volume delivered by most of the pediatric anesthesia ventilators could be large for neonates, and may generate unacceptably high peak airway pressures. The effective tidal volume can however be reduced by connection of a small rubber bag between the ventilator and the expiratory limb of the Ayre's T-piece circuit to divide the delivered gas mixture between the added bag and the neonate's lungs. The delivered tidal volume by the ventilator can then be manipulated to achieve the desired peak inspiratory pressure; 18-20 cm H2O in neonates with normal lung compliance. The modification was found to be simple, safe and convenient.

Nifedipine versus fentanyl to prevent the pressor response to tracheal intubation.

Thirty six patients ASA 1 or 2, undergoing surgery that required tracheal intubation, were allocated randomly into three groups of twelve each. Before induction of anesthesia, they received either saline, 10 mg, nifedipine sublingual, or fentanyl 1.5 micrograms.kg-1 IV. Heart rate (HR), systolic blood pressure (SAP), diastolic blood pressure (DBP), and mean blood pressure (MAP), were recorded automatically every minute for 5 minutes before induction of anesthesia, and for 5 minutes after intubation. Nifedipine was better than fentanyl in blocking the pressor response. The fentanyl dose was too small to abolish this response completely. The increase in HR and blood pressure were most evident in the control group, followed by fentanyl, and the least increase was seen with nifedipine.

Closed circuit coasting from high flow isoflurane anesthesia.

Closed circuit coasting after high flow isoflurane-N2O anesthesia was used in 30 patients undergoing operations expected to last more than one hour. Near the end of the operation, the circuit was closed by shutting off anesthetics and reducing oxygen flow to that necessary to maintain constant end-tidal circuit volume throughout the duration of coasting (Tc). End-tidal isoflurane concentration of 0.5% was a safe target for coasting. Good correlation was found between Tc and anesthetic delivery duration (TAD). An adequate TC for the first hour of TAD was 15 minutes followed by 11 minutes more for each subsequent hour of TAD. The technique is safe, simple, economic, predictable and practical.

Guided isoflurane injection in a totally closed circuit.

Twenty-six patients undergoing middle ear surgery were anaesthetised using a completely closed circuit into which liquid isoflurane was injected using a syringe pump. The injection rate was guided by a table of calculated rates of isoflurane uptake, utilising the square root of time principle, at succeeding time intervals in different weight groups. A constant alveolar concentration of 1.3 MAC was aimed for. The injection rate was changed to that for the higher or lower weight group appropriate to the time interval whenever clinical signs indicated inappropriate depth of anaesthesia. A mean of 10.3 ml liquid isoflurane was used to maintain anaesthesia for a mean of 82.3 minutes. Blood pressure was maintained at 75% of the pre-operative value. Mean arterial blood gas data and changes in plasma catecholamine levels were within the normal range. The mean recovery time was 10.5 minutes. Syringe pump delivery of liquid isoflurane avoided fluctuations that result from bolus injections of unit dose. The implemented injection rate table, working as a therapeutic window, guided redosing, reduced calculation time and served as a record. The technique is safe, economic and adaptable to variations in uptake and response to inhalational anaesthetics.

Nifedipine versus fentanyl to prevent the pressor response to tracheal intubation.

Thirty six patients, ASA I or II, undergoing surgery that required tracheal intubation, were allocated randomly into three groups of twelve. Before induction of anesthesia, they received either saline, nifedipine sublingual 10 mg or fentanyl 1.5 micrograms.kg-1 i.v. Heart rate, systolic blood pressure, diastolic blood pressure and mean blood pressure (MAP) were recorded automatically every minute for 5 minutes before induction of anesthesia, and for 5 minutes after intubation. Nifedipine was better than fentanyl in blocking the pressor response to intubation. The fentanyl dose was too small to abolish this response completely. The increase in HR and blood pressure were most evident in the control group, followed by fentanyl, and the least increase was seen with nifedipine.

Modified sampling connection for sidestream end tidal CO2 monitoring during pediatric anesthesia.

A modification to the sampling connection of Ohmeda 5200 CO2 monitor was done to abolish the increase in apparatus dead space induced by the patient circuit adapter. The modified and the original sampling connections [MSC & OSC] were compared regarding their effects on end tidal CO2 (PECO2), during surgery in 12 anesthetized spontaneously breathing infants and children. The MSC maintained normal PECO2, while it was significantly higher using the OSC.

Hemodynamic changes and glucose utilization during controlled hypotensive anesthesia with labetalol and sodium nitroprusside.

This study was carried on two groups each of 10 patients undergoing major maxillofacial or orthopedic operations. Hypotensive anesthesia was conducted using SNP and labetalol. Labetalol produced hypotension without tachycardia which was evident in the SNP group. Blood sugar increased significantly in both groups. Serum insulin level decreased significantly in the SNP group, while in the labetalol group it showed an insignificant increase.

Enhanced brachial plexus blockade. Effect of pain and muscular exercises on the efficiency of brachial plexus blockade.

Three groups each of 20 patients scheduled to undergo operations on hand or forearm, received supraclavicular brachial plexus blocks with 25 ml lignocaine 1.5%. Patients in the control group did not suffer from pain and were not asked to do muscular exercise. Patients with acute trauma of the upper limb formed the pain group and showed significantly decreased latency for onset of analgesia, partial and complete muscle paralysis. Patients in the muscle exercise group were free of pain and were asked to do muscular exercise for 5 minutes after injection of the lignocaine. Onset of analgesia, partial and complete muscle paralysis was significantly more rapid than in both control and pain groups. Changes in the duration of block were not significant. It is concluded that pain and muscular exercise enhance the onset of brachial plexus blockade.

Myoepithelioma of the head and neck: case report and review.

The clinical, light, and ultrastructure features of a myoepithelioma occurring on the hard palate of a 24-year-old woman are presented and compared with 41 myoepithelioma of the head and neck described in the English literature. These 42 tumors (39 benign and 3 malignant) occurred in individuals from 14 to 81 years of age, affected both sexes about equally, and most often presented as a slowly enlarging, asymptomatic mass. The parotid gland and palate were the most common sites of occurrence. The tumors are typically circumscribed and encapsulated, vary from 1 to 5 cm in the greatest dimension, and are composed of spindled and/or plasmacytoid myoepithelial cells. Prognosis correlates with histologic appearance and parallels that of the pleomorphic adenoma. Conservative excision with a margin of uninvolved tissue is curative. The differential diagnosis and histogenic relationship with other closely related neoplasms are discussed.

Multifocal adenoid cystic carcinoma of the lip.

A 62-year-old Caucasian woman had several distinct and separate adenoid cystic carcinomas which involved both sides of the upper lip. Microscopic examination of the surgical specimens suggested that at least one of these malignant neoplasms arose from a pre-existing basal-cell adenoma.