Clinical application of the pO(2)-pCO(2) diagram

Based on the classic, linear blood gas diagram a logarithmic blood gas map was constructed. The scales were extended by the use of logarithmic axes in order to allow for high patient values. Patients with lung disorders often have high arterial carbon dioxide tensions, and patients on supplementary oxygen typically respond with high oxygen tensions off the scale of the classic diagram. Two case histories illustrate the clinical application of the logarithmic blood gas map. Variables from the two patients were measured by the use of blood gas analysis equipment. Measured and calculated values are tabulated. The calculations were performed using the oxygen status algorithm. When interpreting the graph for a given patient it is recommended first to observe the location of the marker for the partial pressure of oxygen in inspired, humidified air (I) to see whether the patient is breathing atmospheric air or air with supplementary oxygen. Then observe the location of the arterial point (a) to see whether hypoxemia or hypercapnia appears to be the primary disturbance. Finally observe the alveolo-arterial oxygen tension difference to estimate the degree of veno-arterial shunting. If the mixed venous point (v) is available, then observe the value of the mixed venous oxygen tension. This is the most important indicator of global tissue hypoxia.     

Diffusion tensor imaging (DTI) and colored fractional anisotropy (FA) mapping of the subthalamic nucleus (STN) and the globus pallidus interna (GPi)

Introduction  

The subthalamic nucleus (STN) and the globus pallidus internus (GPi) are the most common surgical targets for the treatment of Parkinson’s disease. We studied directionally colored fractional anisotropy (FA) and diffusion tensor imaging (DTI) sequences to better target these anatomical regions.     

Mucous adenocarcinoma of the urinary bladder (urachal carcinoma) (author's transl)

A report is presented of 5 cases of urachal carcinomas (3 women and 2 men). The mucous adenocarcinomas were located on the apex of the urinary bladder. In 3 cases partial cystectomy and in 2 cases a subtotal cystectomy were performed. Two patients were treated with cytostatics postoperatively. The prognosis of urachal carcinomas is poor. 3 patients had metastases to the bones, cerebrum and peritoneum. Diagnostic and therapeutic procedures are discussed.     

Blood vessel supply of the flexor sinews (microanatomy) (author's transl)

Knowledge of the blood vessel supply of the flexor sinews has been considerably enlarged by micro-angiograms. Arrangement of the vessels in the non-tendinous area of the hollow hand is different from that of the osteofibrous channels. The digitalis propriae form arcades, of which the vincula longa and brevia are responsible for segmental supply of the two flexor sinews at the triphalangeal fingers. Tendinous areas without vessels and poor blood supply are most probably supplied by means of diffusion. The intratendinous arrangement of the vessels has led to a change in suturing technique. The long flexor sinew of the thumb is supplied by blood vessels in the thenar region and at the base of the end phalanx.     

Comparison of the pneumooculoplethysmography (GEE) and the digitalized pulse timing oculoplethysmography (ZIRA)

Comparative study of the pneumooculoplethysmography (OPG/Gee) and the digitalized pulse timing OPG (Zira) was conducted by analysis of 100 patients who had both OPG/Gee and Zira and carotid arteriograms. Both units were valuable in diagnosis of normal carotid arteries, 94 per cent for Gee and 89 per cent for Zira. The Gee unit was more valuable in the diagnosis of unilateral significant carotid stenosis, 90.3 per cent versus 75 per cent for the Zira machine. The Gee unit was also very valuable in detecting bilateral carotid stenosis, 90.4 per cent but the Zira unit was limited in this group; i.e., 60 per cent only. The overall accuracy of the OPG/Gee was superior to the OPG/Zira, 92 per cent versus 80 per cent.     

Technique of per-oral endoscopic myotomy (POEM) of the esophagus (with video)

Background

Per-Oral Endoscopic Myotomy (POEM) is becoming an acceptable alternative to laparoscopic cardiomyotomy for esophageal motility disorders. The aim of this video is to provide key technical steps to completing this procedure.

Method

Each patient underwent diagnostic investigations including high resolution manometry (HRM), esophageogastroduodenoscopy (EGD), and timed-barium swallow for primary esophageal motility disorders preoperatively. Patients undergoing POEM procedures are preoperatively prepared by taking Nystatin swish-and-swallow for 3 days, 24 h of clear liquid diet, and 12 h of NPO. Preoperative antibiotics are given. Under general anesthesia and with the patient in the supine position, endoscopy with CO₂ insufflation is prepared. Special endoscopic instruments and electrocautery settings are required to perform the POEM procedure, as illustrated in the slides. POEM is performed in six key/critical steps: (1) diagnostic endoscopy; (2) taking measurements; (3) esophageal mucosotomy creation; (4) submucosal tunneling; (5) selective circular myotomy of the anterior lower esophageal sphincter; and (6) closure of the mucosotomy. According to our protocol, all patients get an esophogram the next morning after surgery prior to discharge. The patient receives objective testing (HRM with 24 PH Impedance test, EGD, and timed-barium swallow) 6 months postoperatively.

Conclusion

In six key steps, POEM can be accomplished as described in the video.     

(iv) Arthroscopy of the elbow

There has been increasing interest in elbow arthroscopy over the past decade with improved techniques and available technology. The indications for elbow arthroscopy have expanded from loose body excision in the arthritic elbow to a variety of procedures including arthroscopic capsular release and excision of the radial head. Complications are rare but potentially devastating, and meticulous surgical technique is necessary to avoid this. This review describes the indications for elbow arthroscopy as well as the general setup and portal placements. The treatment and outcomes for the arthritic elbow, release of capsular contractures, thrower's elbow and other less common pathologies are discussed.     

Dual action of isoflurane on the gamma-aminobutyric acid (GABA)-mediated currents through recombinant alpha(1)beta(2)gamma(2L)-GABA(A)-receptor channels

Isoflurane (ISO) increased the agonist-induced chloride flux through the gamma-aminobutyric acid A receptor (GABA(A)R). This may reflect an anesthetic-induced increase in the apparent agonist affinity. A dual effect of anesthetics was postulated for both the nicotinic acetylcholine receptor (nAChR) and the GABA(A)R. We tested the hypothesis that, in addition to a blocking effect, ISO increases gamma-aminobutyric acid (GABA)-gated currents through recombinant GABA(A)R channels. HEK293 cells were transfected with rat cDNA for alpha(1),beta(2),gamma(2L) subunits. Currents elicited by 1 mM or 0. 01 mM GABA, respectively, alone, or with increasing concentrations of ISO, were recorded by using standard patch clamp techniques. ISO reduced the peak current elicited by 1 mM GABA. Currents induced by 0.01 mM GABA were potentiated by small ISO (twofold at 0.5 mM ISO) and inhibited by larger concentrations. Withdrawal of ISO and GABA induced rebound currents, suggesting an open-channel block by ISO. These currents increased with increasing concentrations of ISO. At large concentrations of ISO, the inhibitory effect predominated and was caused by, at least partly, an open-channel block. At small concentrations of ISO, potentiation of the GABA-gated currents was more prominent. This dual action of ISO indicates different binding sites at the GABA(A)R. The balance between potentiation and block depends on the concentrations of both ISO and GABA.