Continuous-flow delivery of nitrous oxide and oxygen: a safe and cost-effective technique for inhalation analgesia and sedation of pediatric patients.

Nitrous oxide (N2O) safely and rapidly alleviates the pain and distress of minor procedures in the emergency department (ED). We have found self-administration in children does not consistently achieve acceptable analgesia and sedation. The equipment generally available for ED use is designed for adults and delivers 50% N2O through a demand valve that requires an inspiratory effort of -3 to -5 cm of water to activate gas flow. This is difficult for young children who are crying, have more shallow respirations than adults, or cannot follow instructions. In collaboration with the Departments of Anesthesiology, Dentistry, and Respiratory Therapy, we constructed a continuous-flow system for delivering N2O and oxygen (O2). The following is a description of the components, assembly, and use of a continuous-flow machine that safely and inexpensively delivers N2O and O2 to children.

Rapid sequence intubation of the pediatric patient. Fundamentals of practice.

Rapid-sequence intubation and rapid sequence induction of general anesthesia are synonyms and refer to the technique of choice for tracheal intubation in many pediatric patients in the emergency department. The principles of safe practice and basic standards of care uniformly apply to all clinical situations in which the technique is performed. RSI has two basic technical components: induction of general anesthesia and direct laryngoscopy with tracheal intubation. The technique is a prescribed protocol that can be modified slightly by the clinical circumstances. RSI is designed to rapidly create ideal intubating conditions, attenuate pathophysiologic reflex responses to direct laryngoscopy and tracheal intubation, and reduce the risk for pulmonary aspiration. Optimal performance requires appropriate training and knowledge, technical skill, and sound medical judgment. Medical and airway evaluation, careful patient selection, recognition of the need for consultation or safer alternatives, thorough familiarity with appropriate drug management, and attention to detail are essential for minimizing the risk for adverse complications. RSI with a rapid injection of preselected dosages of an anesthetic induction agent and muscle relaxant is the pharmacologic technique of choice. Premedication should not be routinely used. Anticipation, recognition, and management of complications are inherent to the competent delivery of all medical care. The unanticipated difficult airway is arguably the most severe complication of RSI, and all individuals performing the technique must prepare in advance a specific plan for this scenario. As with all such skills or procedures, a quality assurance program is important to monitor care, and individuals practicing RSI need to take appropriate steps to maintain competence.

Does thiopentone delay recovery in children premedicated with midazolam?

This prospective, randomized trial of paediatric surgical outpatients, premedicated with oral midazolam, was designed to determine if an intravenous thiopentone induction of anaesthesia prolongs postoperative recovery compared to an inhalation induction with halothane. One hundred children, one to ten years of age, undergoing ENT surgical procedures of 30-60 min duration received midazolam 0.5 mg.kg-1 with atropine 0.03 mg.kg-1 and were randomized to either halothane (Group 1, n = 50) or a thiopentone induction (Group 2, n = 50) technique, followed by a standardized anaesthetic-protocol. Time to extubation was significantly greater in the thiopentone group (8.8 +/- 4 min vs 7.1 +/- 3 min, P < 0.05). Patients receiving thiopentone were also more sedated than the halothane group on arrival in the PARR (3.9 +/- 1.5, 3.3 +/- 1.7, respectively P < 0.05), but the differences disappeared after 30 min. Children premedicated with oral midazolam who receive an intravenous thiopentone induction have a slightly prolonged emergence from anesthesia compared to children induced with halothane.

CT findings after uncomplicated and complicated laparoscopic cholecystectomy.

Laparoscopic cholecystectomy (LC) is quickly becoming the standard procedure for gallbladder removal. Recent studies indicate that this new procedure compares favorably with open cholecystectomy in mortality and overall morbidity. Imaging has assumed an important role in the diagnosis and management of postoperative complications. This report reviews the CT findings after uncomplicated LC as well as the spectrum of CT findings seen with various postoperative complications.

Postoperative dissemination of fat particles in the subarachnoid pathways.

A case of postoperative dissemination of fat particles into the cerebrospinal fluid pathways is reported. Following removal of a foramen magnum meningioma, a postoperative MR scan showed fat droplets in the basal cisterns and in the frontal horns of the lateral ventricles. The patient was asymptomatic and a repeat MR scan 7 months later was normal, with resolution and clearing of the previously noted cerebrospinal fluid fat.

Hepatopulmonary fistula: treatment with biliary metallic endoprosthesis.

Hepatopulmonary communication, most commonly in the form of bronchobiliary fistula, is an unusual lesion that can occasionally close spontaneously, but usually requires surgical therapy. The usual treatment has been a combined thoracoabdominal approach with correction of the fistulous tract or an abdominal approach to correct the causative bile duct obstruction. Both endoscopic and percutaneous therapy of the biliary ductal system have been described as forms of treatment. We present a case of hepatopulmonary fistula in a patient with bilioptysis, treated with percutaneous biliary metallic endoprosthesis. To our knowledge, this is the first reported case in which metallic stents were used to treat a hepatopulmonary fistula.

Retroaortic renal vein with tumor thrombus: MR findings.

The magnetic resonance (MR) findings in a case of tumor extension into a retroaortic renal vein from a renal cell carcinoma are reported. The signal characteristics of the tumor thrombus paralleled those of the renal mass, and the preoperative recognition of the anomalous vessel lead to an altered surgical approach.

CT findings after uncomplicated percutaneous laparoscopic cholecystectomy.

To investigate the postoperative pulmonary and abdominal findings following uncomplicated percutaneous laparoscopic cholecystectomy, 27 patients were studied by upper abdominal CT within 24 h of the surgical procedure. Both pneumoperitoneum (70%) and subcutaneous emphysema (56%) were commonly observed. Postoperative atelectasis and pleural effusions were observed in 44 and 33% of the patients, respectively. Forty-eight percent of the patients had a postoperative ileus demonstrated by CT. Approximately 22% of the patients had fluid in the abdomen as either edema in the gallbladder fossa or small amounts of ascites. In our patients the amount of ascitic fluid was small and no clinical significance could be attributed to the intraabdominal fluid collections.

A rare cause of parastomal hernia: stomach herniation.

Our case of a parastomal hernia is rare because the stomach became incarcerated in the hernial sac. The diagnosis of parastomal hernia is not a difficult one, but one must be aware of the possible complications of the colostomy and the rare occurrence of the parastomal hernia containing the stomach.

Fast neutrons from a 25-MeV betatron.

Since published results for the fast-neutron dose per x-ray rad from high-energy therapy installations have differed by as much as a factor of 300, we have measured the neutron production from our 25-MeV betatron. Fast-neutron activation of aluminum foils was the method used. The effect of photoneutron production in the detectors, which has affected some past work, has been eliminated. A major source of neutrons in the treatment field was the platinum target. The neutron spectra used in the calculations of fluence were obtained by interpolation between published energies and between neighboring elements. Fluences per rad of x rays without a phantom were largely independent of field size and energy in the range 18-23 MeV. At 100 cm SSD and 23 MeV a large beam flattener contributed 15% of the neutrons, the remainder coming equally from the target and background. A phantom increased the neutron fluence/rad of x rays by 0%-10% depending on the field size. At 23 MeV we estimated the neutron dose to a patient to be 2.2 X 10(-4) rad per rad of x rays inside the treatment field and 3 X 10(-5) at 20 cm outside the field. The uncertainty in these figures is believed to be +/- 50%. In the electron beam the neutron dose per rad was about 50 times smaller than in the x-ray beam. Estimates were made of neutron fluences at other energies and target thicknesses. We discuss our results in comparison with those of others.