The effect of the modified Z trendelenburg position on intraocular pressure during robotic assisted laparoscopic radical prostatectomy: a randomized, controlled study.

PURPOSE: The Trendelenburg position has a dramatic effect on circulation, consequently increasing cerebral and intraocular pressure. We evaluated whether modifying the Trendelenburg position would minimize the increase in intraocular pressure. MATERIALS AND METHODS: In this prospective, randomized, controlled study we compared intraocular pressure in patients undergoing robot-assisted laparoscopic radical prostatectomy while in the Trendelenburg position or the modified Z Trendelenburg position. In group 1 intraocular pressure, blood pressure and endotracheal CO2 were measured in the patient at anesthesia induction (time 1), before positioning (time 2), and while in the Trendelenburg position (time 3) and in the modified Z Trendelenburg position (time 4). They were also measured after pneumoperitoneum (time 5), every 30 minutes (times 6 to 16), while supine at the end of pneumoperitoneum (time 17) and before awakening (time 18). We modified the Trendelenburg position by placing the head and shoulders horizontally. RESULTS: Group 1 included 29 patients in the modified Z Trendelenburg position. Group 2 included 21 patients in the Trendelenburg position. No difference was found in patient demographics or surgical outcomes. Median intraocular pressure was in the low normal range at times 1 and 2, and increased in time 3 in each group. From time 4 intraocular pressure decreased and at all time points it was significantly lower in group 1 by a mean of 4.61 mm Hg (95% CI -6.90-2.30, p <0.001). At time 17 mean intraocular pressure decreased to normal (19.6 mm Hg) in group 1 but remained in the hypertensive range (24.9 mm Hg) in group 2. At time 18 mean intraocular pressure was 17 mm Hg in each group. Blood pressure was significantly lower in group 1 with a mean reduction in systolic and diastolic pressure of 6.3 and 4.3 mm Hg, respectively. CONCLUSIONS: Our results suggest that modifying the Trendelenburg position during robot-assisted laparoscopic radical prostatectomy has a significant positive effect on patient neuro-ocular safety by lowering intraocular pressure and accelerating its recovery to the normal range without affecting the operation.

The effect of hypocapnia on the autoregulation of cerebral blood flow during administration of isoflurane.

Isoflurane impairs autoregulation of cerebral blood flow in a dose-related manner. Previous investigations in several other conditions have demonstrated that impaired autoregulation can be restored by hyperventilation. We hypothesized that hypocapnia may restore cerebral autoregulation impaired by isoflurane anesthesia. We administered isoflurane in 100% oxygen to 12 healthy patients aged 21-59 yr scheduled for elective nonneurological surgery. Isoflurane end-tidal concentration was individualized at 0.1% to 0.2% less than that required to induce short periods of isoelectric electroencephalogram. This resulted in an end-tidal isoflurane concentration of 1.6% +/- 0.2% (mean +/- sd) corresponding to an age-adjusted minimum alveolar anesthetic concentration multiple of 1.4. Mean arterial blood pressure was reduced to <80 mm Hg, by infusion of remifentanil if required. Cerebral autoregulation was assessed by infusing phenylephrine to increase mean arterial blood pressure to 100 mm Hg while monitoring middle cerebral artery blood flow velocity with transcranial Doppler ultrasonography. The change in flow velocity was used to calculate the autoregulation index (ARI). The ARI ranges between 0 and 1 and an ARI < or =0.4 indicates significantly impaired autoregulation. Autoregulation was tested twice in randomized order: once during normocapnia (Paco(2) 38-43 mm Hg) and once during hypocapnia (Paco(2) 27-34 mm Hg). The median (interquartile range) ARI was 0.29 (0.23-0.64) during normocapnia and 0.77 (0.70-0.78) during hypocapnia (P < 0.005). Of the 12 subjects, autoregulation was significantly impaired in 8 subjects during normocapnia and none during hypocapnia (P = 0.001). Hypocapnia restored cerebral autoregulation in normal subjects during isoflurane-induced impairment of autoregulation.

Psychological recuperation of the patient.

This seldom discussed subject is brought into focus with examples of the complex emotional ramifications of eye loss. The professional who is best equipped to counsel these patients is the ocularist. Patients psychological needs are successfully met with accurate information. Our objective is to alter the patient's attitude concerning losing an eye. A step-by-step method of achieving that goal is presented.

Recovery after loss of an eye.

Recovery after loss of one eye requires an adjustment to monocular vision and resolution of a significant, serious emotional trauma. The impact on everyday life is not well documented. We surveyed 125 monocular patients by questionnaire regarding their recovery. Eighty-five of 125 respondents reported that loss of one eye had not changed their life in any permanent way. Only seven reported persistent visual problems, whereas 12 described problems in employment and 21 had anxiety or poor self-image. Among 49 adults who had suddenly lost a sighted eye, 50% reported that their adjustment period for driving, work, recreation, home activities, or walking was less than 1 month. Ninety-three percent thought that their adjustment was completed by 1 year. In conclusion, most patients were able to resume everyday activities after a short period of adjustment. Problems with employment and self-image were frequent, but visual problems were unusual.

Automated gunshot residue particle search and characterization.

The main disadvantage to gunshot residue (GSR) particle analysis utilizing scanning electron microscope/energy dispersive X-ray (SEM/EDX) instrumentation has been the excessive operator time required for search and identification. This study uses an automated particle search and characterization program for unattended GSR search and identification. This system allows for automatic matrix search, particle sizing, chemical typing, and spectral aquisition with subsequent storage of data to disk for later operator review and verification. This work describes various aspects of the program, determines appropriate parameters adequate for both unique and characteristic GSR particle identification, and evaluates the reliability of data obtained. Samples are collected via the tape lift method from test-firings of .38, .32, .25, and .22 caliber handguns at time after firing intervals of 0 to 6 h. Unique GSR particles are consistently and correctly identified by this method on tape lift samples taken up to 4 h after firing. False positive results of unique GSR particles are not encountered on control handblank samples. This technique appears to provide the forensic science community with an operator-free method of reliable GSR particle search and an improved analyst-time-per-case ratio.

[Favourable erythrocyte rheology in patients with glucose-6-phosphate dehydrogenase deficiency (author's transl)]. / Günstige rheologische Iegenschaften der Erythrozytem beim Glucose-6-phosphatdehydrogenase-mangel

The rheological properties of erythrocytes of 6 patients with glucose-6-phosphate dehydrogenase deficiency were studied. A method of filtration and measurements of viscosity of erythrocyte suspensions with a hematocrit of 80% were used. The erythrocytes of all patients were more flexible than the erythrocytes of healthy controls. The erythrocytes of the patients passed the polycarbonate filters with a pore diameter of 5 micron more rapidly and showed a lower viscosity of erythrocyte suspensions. The increased flexibility of erythrocytes was due to a lower hemoglobin content which was measured in isolated ghosts. After incubation of the cells with acetylphenylhydrazine, Heinz bodies formed in the erythrocytes of controls. The flexibility of these cells decreased markedly. Though more Heinz bodies were found in the erythrocytes of the patients when the cells were incubated under identical conditions, even these erythrocytes became less rigid than the erythrocytes of controls. From these results we condlude that the more flexible erythrocytes of the patients could pass the splenic sinus even when they contain Heinz bodies. The rheological properties of the erythrocytes explain why splenectomy is not efficient in glucose-6-phosphate dehydrogenase deficiency.

Organization of enzymes of glycolysis and of glutathione metabolism in human red cell membranes.

1) The activities of 16 enzymes of glycolysis and of glutathione metabolism were determined in intact human red cell membranes (ghosts) which were prepared by hypotonic hemolysis. 2) Enzymes and hemoglobin of the ghosts were resolved by two toluene extractions. Only the four enzymes hexokinase, fructose-bisphosphate aldolase, glyceraldehyde-phosphate dehydrogenase and pyruvate kinase could not be released completely from the ghosts. 3) The residual membrane fraction, which was obtained after the toluene extraction of ghosts prepared at 30 imOsM, contained 0.02% of the original hemoglobin content of the red cell. Between 6.5 and 23% of the hemolysate activities of glyceraldehyde-phosphate dehydrogenase, phosphoglycerate kinase, pyruvate kinase and fructose-bisphosphate aldolase were detected in this fraction after mechanical disruption. 4) Sonication of intact ghosts increased the activities of fructose-bisphosphate aldolase, pyruvate kinase and phosphoglycerate kinase. 5) In "white" ghosts prepared at 5 imOsM phosphate buffer which contained 0.5% of the original hemoglobin the activities of fructose-bisphosphate aldolase and glyceraldehyde-phosphate dehydrogenase were detected at high levels. The activities of pyruvate kinase and phosphoglycerate kinase were low in these preparations. 6) The results indicate that one part of all enzymes is loosely attached to the inner surface of the membrane as is hemoglobin. A second part, the "cryptic enzyme activity", is available after resolving by toluene. A residual part of four enzymes is firmly bound to the membrane. Two of them (fructose-bisphosphate aldolase and glyceraldehyde-phosphate dehydrogenase) are oriented toward the inner surface of the membrane, whereas pyruvate kinase and phosphoglycerate kinase are hidden in the lipid core of the membrane.