The effect of intermittent intraabdominal pressure elevations and low cardiac output on the femoral to carotid arterial blood pressure difference in piglets.

BACKGROUND: Our previous work in a laparoscopic setting in piglets revealed that the systolic femoral artery pressure was approximately 5 % higher than its carotid counterpart, whereas the mean and diastolic values showed no significant difference. This remained idem when the intraabdominal pressure (IAP) was gradually increased. In this study, we aimed to investigate the effect of (1) intermittent IAP elevations and (2) a low cardiac output (CO) on the blood pressure (BP) difference cranially (carotid artery) and caudally (femoral artery) of a capnoperitoneum (ΔP = P a fem-P a carot). METHODS: A total of twenty-two piglets (mean body weight 11.0 kg; range 8.9-13.3 kg) were studied. Of these, 14 underwent intermittent IAP elevations at 8 and 16 mmHg, and ΔP was measured. In another 8 piglets, a model of reduced CO was created by introducing an air embolism (2 ml/kg over 30 s) in the inferior caval vein (VCI) at 12 mmHg IAP to further assess the influence of this variable on ΔP. RESULTS: Systolic ΔP remained at a mean of 5.6 mmHg and was not significantly affected by insufflation or exsufflation up to an IAP of 16 mmHg. Diastolic and mean values showed no differences between P a carot and P a fem. P a fem, systol remained higher than its carotid counterpart as long as the cardiac index (CI) was above 1.5 l/min/m2, but fell significantly below P a carot, systol at a low CI. There was no CO-dependent effect on diastolic and mean ΔP. Repeated IAP elevations do not significantly influence ΔP. CONCLUSIONS: Intermittent IAP elevations do not significantly influence ΔP. Despite of a CO-dependent inversion of systolic ΔP, mean BP measurements at the leg during laparoscopy remain representative even at low CO values.

Air in the insufflation tube may cause fatal embolizations in laparoscopic surgery: an animal study.

BACKGROUND: The aim of this study was to evaluate the risk of an air embolization with the volume of the insufflation tube during induction of laparoscopy. A further objective was to determine the LD50 of air in young piglets. METHODS: End-tidal carbon dioxide pressure ([Formula: see text]), pulmonary arterial pressure (P pa), heart rate (f c), and mean arterial pressure (P a carot) were measured in 17 piglets divided into three groups: group 1 (n = 6), bolus application (CO2 embolization, followed by air embolization, 2 mL/kg each), group 2 (n = 7), continuous air embolization (30 min, 0.2 mL/kg/min), and group 3 (n = 4), continuous CO2 embolization (30 min, 0.4 mL/kg/min). RESULTS: All animals survived CO2 embolism. Air embolization as a bolus (2 mL/kg) or with an accumulated volume of 3.1 mL/kg led to death. Decreases in [Formula: see text] indicated air or massive CO2 embolization only. There was a good correlation between [Formula: see text] and P pa in case of air embolization (r = -0.80, p < 0.0001). In contrast, no dependency was recognized during CO2 embolism (r = -0.17, p = 0.2). CONCLUSIONS: In order to minimize the lethal risk of gas embolization, the insufflation system has to be completely filled with CO2 before connecting to the patient.

Evaluation of severely displaced radial neck fractures in children treated with elastic stable intramedullary nailing.

BACKGROUND: We performed a retrospective case study of 28 consecutive severely displaced radial neck fractures (Judet types III and IV) in children treated with elastic stable intramedullary nailing using the Metaizeau technique. METHODS: We reviewed all preoperative radiographs and classified the injuries according to Judet. All patients were asked to return for later assessment. They underwent physical examination; radiographs were taken; and they were asked for subjective assessment. An evaluation of clinical results was performed using the Mayo Elbow Performance Score (MEPS). RESULTS: According to Judet classification there were 13 type III and 15 type IV fractures. Using the MEPS, excellent results were achieved in 23 cases (82%) and good results in 5 cases (18%). The average MEPS was 97 points. Five patients complained of mild pain. Three malunions were observed. CONCLUSIONS: Elastic stable intramedullary nailing is a minimally invasive technique, allowing stable fixation and providing excellent to good outcomes with a low complication rate. LEVEL OF EVIDENCE: We performed a retrospective level 4 study of case series.

Comparison of two different CPAP systems by tidal breathing parameters.

OBJECTIVE: Comparison of tidal breathing and pressure fluctuation of the continuous positive airway pressure (CPAP) associated with the use of the valveless Infant Flow System versus the conventional constant-flow CPAP (Babylog 8000) in preterm infants. DESIGN: Randomized cross-over trial. SETTING: Neonatal intensive care unit level III. PATIENTS: Twenty infants; median (range): birth weight 1,035 g (640-4,110 g), actual weight 1,165 g (820-4,250 g), gestational age at birth 27 (26-40) weeks. INTERVENTIONS: After extubation two CPAP devices (Infant Flow System vs Babylog 8000) were applied in a random order to the same infant. Fluctuations of the applied pressure during the breathing cycle and tidal breathing parameters were measured by the flow-through technique. MAIN RESULTS: Using the Infant Flow System the mean (standard deviation) inspiratory flow [1.5 (0.1) vs 1.3 (0.1) l.min(-1).kg(-1), P<0.05] and tidal volume were significantly increased [5.3 (1.3) vs 4.7 (1.3) ml/kg(-1), P<0.05] compared to Babylog 8000. The fluctuations of the applied pressure of the Infant Flow System during the breathing cycle were significantly lower [0.1 (0.03) kPa vs 0.15 (0.08) kPa, P<0.05] compared to Babylog 8000. No differences were seen in the duration of inspiration and expiration and the time to peak tidal flow. In the Infant Flow System pressures during expiration remained stable whereas they increased during the use of Babylog 8000. CONCLUSIONS: Within-subject comparisons of tidal breathing parameters of the two CPAP devices Infant Flow System and Babylog 8000 show: (1) a significant influence of the system used; and (2) that the valveless Infant Flow System increases air flow and tidal volume with less fluctuations in CPAP pressures during the breathing cycle.

Embolism risk analysis--helium versus carbon dioxide.

BACKGROUND: Helium is used as an insufflation gas to avoid the negative properties of carbon dioxide (CO(2)), such as CO(2) accumulation, acidosis, and tachycardia, particularly in the case of insufficient respiratory function, seen also in infancy. Any laparoscopic procedure carries the risk of a gas embolism. MATERIALS AND METHODS: Seven anesthetized piglets (weighing 9.9-12.8 kg), randomized into three groups, served as models for pre-teenage children. Three piglets received a CO(2) embolism, followed by a helium embolism of 2 mL/kg, respectively. Helium was administered to three piglets, whereas both gases were repeatedly administered alternately to one piglet. The embolisms were administered for 30 seconds via a central venous line. Cardiac output was measured using the thermodilution method. The observation period for each embolism was 60 minutes in Groups 1 and 2 and 15 minutes in Group 3. RESULTS: All animals survived CO(2) embolisms. Four of the six piglets died after helium embolisms. Following helium embolisms there was a prompt initial decrease in the end-tidal CO(2) pressure and an initial increase in the pulmonary arterial pressure. A further decrease in arterial blood pressure was prevented by a compensatory increase in the heart rate and appeared just before death. After only 5 minutes cardiac output showed a 25% decline from the initial value. Helium embolisms led to a severe increase in the pulmonary dead space. CONCLUSIONS: Embolisms with the smallest amounts of helium administered via direct venous puncture have an immediate lethal impact. Extended perioperative monitoring and trocar placement under vision should be performed.

Laparoscopic inguinal hernia repair does not impair testicular perfusion.

BACKGROUND: Laparoscopic inguinal hernia repair techniques close the internal ring with a suture. Concern has been raised whether or not the testicular vessels are compromised with this technique. This study was undertaken to evaluate pre- and postoperative testicular perfusion and to compare it with healthy controls. PATIENTS AND METHOD: Sixty-five boys (aged 6 weeks to 11 years; median, 1.4 years) with unilateral (n = 52) or bilateral (n = 13) inguinal hernias were treated laparoscopically. Testicular perfusion was measured using a recently developed neuromonitoring device (O2C; LEA Medizintechnik GmbH, Giessen, Germany), which combines light spectroscopy and laser Doppler technique. An optical probe was placed on the surface of each scrotal pouch for measurements at 2 depths (2 and 8 mm). Measurements involved oxygen (O(2)) saturation at the venous end of capillaries, the amount of hemoglobin within microvessels, the blood flow within microcirculation, and the velocity of the blood in microcirculation. Measurements were conducted before and after anesthesia, before and after surgery, and 6 weeks later. Twenty-one healthy boys of similar ages served as controls. RESULTS: Measurements at 2-mm depth were unreliable. At 8-mm depth, the oxygen saturation of hemoglobin was between 62% and 75% (hypoxia would be <10%). The relative blood flow was between 160 to 235 arbitrary units, better than in healthy awake controls. Values were solely influenced by the administered fraction of inspired oxygen. Relative hemoglobin volume of the testes and blood flow velocity remained unchanged after surgery. Values were also normal when measured during early and long-term follow-up. CONCLUSION: Laparoscopic inguinal hernia repair using suture closure of the internal inguinal ring does not impair testicular perfusion.

Pediatric fractures of the carpal scaphoid: a retrospective clinical and radiological study.

A retrospective study was undertaken of 22 carpal scaphoid fracture patients younger than 18 years. Of these, 17 patients received conservative treatment, and 5 received treatment involving screw fixation with or without a bone graft from the iliac crest. Clinical outcomes were evaluated using the Cooney score. Radiographs were analyzed with respect to the site of the fracture, the course of the fracture gap, displacement, and time to union. According to the Cooney score, in 94% of patients, good or excellent results were obtained. A total of 94% of patients considered their result as good or excellent. All fractures healed. Malunion was evident in 1 case.