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 The pulmonary artery catheter was gently withdrawn and the balloon inflated, with cessation of bleeding.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.

A fast response membrane-based pH indicator optode.

A cellulose acetate based optode membrane containing 4-dimethylamino-4'-octylazobenzene as an acid-base indicator is described. Other essential components of the membrane for a fast-responding and durable sensor are diethyl phthalate, triethyleneglycol and potassium tetrakis(4-chlorophenyl)borate. Factors affecting the sensor behaviour are discussed and an application in a flow-cell is demonstrated.

Direct or modified Seldinger guide wire-directed technique for arterial catheter insertion.

Percutaneous radial artery cannulation is widely used for direct continuous arterial blood pressure measurement and sampling of arterial blood. We compared the success rate of arterial catheter placement in patients undergoing aortocoronary bypass operations using the direct and the modified Seldinger techniques. The effects of gender and quality of the pulse were also investigated. Our study group consisted of 42 female and 96 male patients. The overall success rate with the guide wire was 82% compared with that of the direct method of 65% (P = 0.02). The success rate for arterial cannulation in male patients was high whether direct cannulation or a guide wire was used. In female patients, on the other hand, the failure rate with the direct technique was high (57%) and was significantly lower (14%) when the guide wire was used (P < 0.001). We conclude that the success rate for cannulation is high in male patients, and patients with a bounding pulse regardless of the use of the direct or guide-wire techniques. The guide wire is recommended as the initial technique for cannulating the radial artery of female patients. In patients with a thready pulse, no significant advantage could be obtained by using a guide wire, but in salvaging an arterial line the guide wire is efficacious.

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.

Comparison of low-dose sufentanil and fentanyl in balanced intravenous anesthesia for orthotopic cardiac transplantation.

A retrospective review was made of the records of 118 patients who received orthotopic heart transplant. Anesthetic techniques, drugs, dosage, hemodynamic profiles, intubation time, and intensive care unit stay were evaluated. The efficacy of sufentanil was compared to fentanyl in a balanced anesthetic when given in lower doses. Patients were given adequate anesthesia with total opioid doses of sufentanil, 6.5 +/- 2.9 micrograms.kg-1, or fentanyl, 58.9 +/- 24.9 micrograms.kg-1. Midazolam was used in all patients (mean dose 7.6 +/- 3.8 mg). There were no differences between the groups in complications, requirements for inotropic support, or time to extubation. A significantly higher pulmonary artery pressure was noted in patients who received sufentanil, but not fentanyl, pretransplant. The pulmonary artery pressures were not significantly elevated posttransplant. This review indicated that patients can be safely anesthetized with either combination of drug in lower doses than previously recommended.

Flow-injection determination of phosphate with a cadmium ion-selective electrode.

A flow-injection method is described, in which phosphate standards are introduced into a reagent stream containing Cd(2+) ,resulting in the formation of Cd(3)(PO(4))(2). The associated reduction in free metal concentration is sensed by a cadmium-selective electrode. With the exception of major interference from iodide and moderate interference from bromide and thiocyanate, the system exhibits excellent response to phosphate and selectivity over several common anions in solutions buffered at pH 8.4. A maximum sampling rate of 160/hr is possible for phosphate standards in the concentration range 10(-1)-10(-1)M with a 10(-4)M Cd(2+) reagent stream at a total flow-rate (carrier and reagent stream combined) of 8.4 ml/min.

Potentiometric flow-injection determination of iodide and iodine.

A potentiometric flow-injection system is described, in which iodide in the concentration range 10(-6)-10(-1)M may be determined at rates of up to 360 samples/hr at a flow-rate of 17.8 ml/min. Iodine, after on-line reduction to iodide with 0.1M sodium metabisulphite, can also be determined, with a throughput of 60 samples/hr for 10(-5)-10(-3)M iodine. Analyses of two pharmaceutical preparations for iodide and iodine are reported, and the results are in reasonable agreement with titrimetric values.

Electroimmunoassay. A new competitive protein-binding assay using antibody-sensitive electrodes.

A novel technique is reported in which an antibody-sensitive electrode for anti-prostaglandin E2 antisera was used to measure solution-phase PGE2 in nanomolar quantities. The electrode was constructed by incorporating a cation-selective ionophore-hapten (PGE2) conjugate into a polyvinyl chloride membrane. Transmembrane potential in a fixed potassium gradient was measured. The addition of anti-PGE2 antisera changed membrane potential in a concentration-dependent manner. The effect of anti-PGE2 antibodies on membrane potential was decreased by adding free PGE2 to the buffer-containing antisera. With this technique a competitive protein-binding assay was developed, and standard curves for solution-phase PGE2 were generated over a concentration range of 1 to 1,000 nM. The assay was relatively specific for PGE2; PGD2 and PGF2a had only minor effects on transmembrane potential over the effective concentration range for PGE2.