Optimal treatment strategies for hepatic portal venous gas: A retrospective assessment.

BACKGROUND: Hepatic portal venous gas (HPVG) generally indicates poor prognoses in patients with serious intestinal damage. Although surgical removal of the damaged portion is effective, some patients can recover with conservative treatments. AIM: To establish an optimal treatment strategy for HPVG, we attempted to generate computed tomography (CT)-based criteria for determining surgical indication, and explored reliable prognostic factors in non-surgical cases. METHODS: Thirty-four cases of HPVG (patients aged 34-99 years) were included. Necessity for surgery had been determined mainly by CT findings (i.e. free-air, embolism, lack of contrast enhancement of the intestinal wall, and intestinal pneumatosis). The clinical data, including treatment outcomes, were analyzed separately for the surgical cases and non-surgical cases. RESULTS: Laparotomy was performed in eight cases (surgical cases). Seven patients (87.5%) survived but one (12.5%) died. In each case, severe intestinal damage was confirmed during surgery, and the necrotic portion, if present, was removed. Non-occlusive mesenteric ischemia was the most common cause (n = 4). Twenty-six cases were treated conservatively (non-surgical cases). Surgical treatments had been required for twelve but were abandoned because of the patients' poor general conditions. Surprisingly, however, three (25%) of the twelve inoperable patients survived. The remaining 14 of the 26 cases were diagnosed originally as being sufficiently cured by conservative treatments, and only one patient (7%) died. Comparative analyses of the fatal (n = 10) and recovery (n = 16) cases revealed that ascites, peritoneal irritation signs, and shock were significantly more frequent in the fatal cases. The mortality was 90% if two or all of these three clinical findings were detected. CONCLUSION: HPVG related to intestinal necrosis requires surgery, and our CT-based criteria are probably useful to determine the surgical indication. In non-surgical cases, ascites, peritoneal irritation signs and shock were closely associated with poor prognoses, and are applicable as predictors of patients' prognoses.

Exploring the use of single-port surgery in the conservative management of hepatic portal vein gas: A case report.

RATIONALE: Hepatic portal vein gas (HPVG) is known as a sign of a lethal condition resulting from bowel necrosis. Recently, the detection rate of non-life-threatening cases of HPVG has increased due to the technological development of imaging, i.e., computed tomography (CT). However, it is difficult to determine accurately whether surgical treatment is necessary because of its lethal potential. PATIENT CONCERNS: A 74-year-old woman suddenly complained about lower abdominal pain and vomiting after an operation for cervical spondylosis myelopathy. Her vital signs were slightly unstable and she was perspiring and exhibited pallor. Muscular defense was not clear, though her abdomen was tender and slightly distended. DIAGNOSIS: CT results showed massive HPVG. However, laboratory investigation did not clearly indicate bowel necrosis. Also, a contrast-CT scan was not performed due to her chronic renal dysfunction and asthma. INTERVENTION: Exploration was performed by single-port surgery (SPS) instead of exploratory laparotomy. OUTCOME: This approach showed no ischemic bowel and so conservative therapies were undertaken with confidence. The HPVG disappeared 2 days later, and she recover completely from the illness. LESSONS: HPVG requires immediate and reliable decision for management. However, unnecessary exploratory laparotomy should be avoided. Hence, a novel strategy should be considered in light of innovative surgical procedures. Our experience suggested that SPS was useful as an exploratory tool for the management of HPVG.

Reliability of venous gas embolism detection in the subclavian area for decompression stress assessment following scuba diving.

INTRODUCTION: Ultrasonic detection of venous gas emboli (VGE) in the precordial (PRE) region is commonly used in evaluation of decompression stress. While subclavian (SC) VGE detection can also be used to augment and improve the evaluation, no study has rigorously compared VGE grades from both sites as decompression stress indicators. METHODS: This retrospective study examined 1,016 man-dives breathing air extracted from the Defence Research and Development Canada dataset. Data for each man-dive included dive parameters (depth, bottom time, total ascent time), PRE and SC VGE grades (Kisman-Masurel) and post-dive decompression sickness (DCS) status. Correlation between SC and PRE grades was analyzed and the association of the probability of DCS (pDCS) with dive parameters and high bubble grades (HBG III- to IV) was modelled by logistic regression for SC and PRE separately for DCS risk ratio comparisons. RESULTS: PRE and SC VGE grades were substantially correlated (R = 0.66) and were not statistically different (p = 0.61). For both sites, pDCS increased with increasing VGE grade. When adjusted for dive parameters, the DCS risk was significantly associated with HBG for both PRE (p = 0.03) and SC (p < 0.001) but the DCS risk ratio for SC HBG (RR = 6.0, 95% CI [2.7-12.3]) was significantly higher than for PRE HBG (RR = 2.6, 95% CI [1.1-6.0]). CONCLUSIONS: The association of bubble grades with DCS occurrence is stronger for SC than PRE when exposure severity is taken into account. The usefulness of SC VGE in decompression stress evaluation has been underestimated in the past.

[Diving accidents]. / Tauchunfälle.

Decompression injuries occur on account of the special hyperbaric effects during the emerge phase and require superior therapeutic knowledge. Vitally important is emergency treatment with high concentrated oxygen at an early stage. Sever decompression injuries require oxygenation in a hyperbaric treatment chamber.

Size distribution of air bubbles entering the brain during cardiac surgery.

BACKGROUND: Thousands of air bubbles enter the cerebral circulation during cardiac surgery, but whether high numbers of bubbles explain post-operative cognitive decline is currently controversial. This study estimates the size distribution of air bubbles and volume of air entering the cerebral arteries intra-operatively based on analysis of transcranial Doppler ultrasound data. METHODS: Transcranial Doppler ultrasound recordings from ten patients undergoing heart surgery were analysed for the presence of embolic signals. The backscattered intensity of each embolic signal was modelled based on ultrasound scattering theory to provide an estimate of bubble diameter. The impact of showers of bubbles on cerebral blood-flow was then investigated using patient-specific Monte-Carlo simulations to model the accumulation and clearance of bubbles within a model vasculature. RESULTS: Analysis of Doppler ultrasound recordings revealed a minimum of 371 and maximum of 6476 bubbles entering the middle cerebral artery territories during surgery. This was estimated to correspond to a total volume of air ranging between 0.003 and 0.12 mL. Based on analysis of a total of 18667 embolic signals, the median diameter of bubbles entering the cerebral arteries was 33 µm (IQR: 18 to 69 µm). Although bubble diameters ranged from ~5 µm to 3.5 mm, the majority (85%) were less than 100 µm. Numerous small bubbles detected during cardiopulmonary bypass were estimated by Monte-Carlo simulation to be benign. However, during weaning from bypass, showers containing large macro-bubbles were observed, which were estimated to transiently affect up to 2.2% of arterioles. CONCLUSIONS: Detailed analysis of Doppler ultrasound data can be used to provide an estimate of bubble diameter, total volume of air, and the likely impact of embolic showers on cerebral blood flow. Although bubbles are alarmingly numerous during surgery, our simulations suggest that the majority of bubbles are too small to be harmful.

Performance assessment of the Simplified Acute Physiology Score II, the Acute Physiology and Chronic Health Evaluation II score, and the Sequential Organ Failure Assessment score in predicting the outcomes of adult patients with hepatic portal venous gas in the ED.

OBJECTIVE: This study aims to evaluate the performance of Simplified Acute Physiology Score II (SAPS II), the Acute Physiology and Chronic Health Evaluation II (APACHE II) score, and the Sequential Organ Failure Assessment (SOFA) score for predicting illness severity and the mortality of adult hepatic portal venous gas (HPVG) patients presenting to the emergency department (ED). This will assist emergency physicians in risk stratification. METHODS: Data for 48 adult HPVG patients who visited our ED between December 2009 and December 2013 were analyzed. The SAPS II, APACHE II score, and SOFA score were calculated based on the worst laboratory values in the ED. The probability of death was calculated for each patient based on these scores. The ability of the SAPS II, APACHE II score, and SOFA score to predict group mortality was assessed by using receiver operating characteristic curve analysis and calibration analysis. RESULTS: The sensitivity, specificity, and accuracy were 92.6%,71.4%, and 83.3%, respectively, for the SAPS II method; 77.8%, 81%, and 79.2%, respectively, for the APACHE II scoring system, and 77.8%, 76.2%, and 79.2%, respectively, for the SOFA score. In the receiver operating characteristic curve analysis, the areas under the curve for the SAPS II, APACHE II scoring system, and SOFA score were 0.910, 0.878, and 0.809, respectively. CONCLUSION: This is one of the largest series performed in a population of adult HPVG patients in the ED. The results from the present study showed that SAPS II is easier and more quickly calculated than the APACHE II and more superior in predicting the mortality of ED adult HPVG patients than the SOFA. We recommend that the SAPS II be used for outcome prediction and risk stratification in adult HPVG patients in the ED.

Retinal angiography: noninvasive, real-time bubble assessment from the ocular fundus.

Formation of bubbles in tissue and vasculature from a sudden reduction in ambient pressure is likely an underlying cause of the clinical symptoms of decompression sickness (DCS). Thus, tools detecting bubbles in the vasculature may be important for evaluating DCS. Sheep were air-compressed to 6.0 ATA (30 minutes bottom time) then rapidly decompressed to the surface. A fundus camera was quickly positioned for continuous observation of the retinal vasculature. Bubbles were observed in the retinal vasculature of 25.8% (n = 31) of the sheep. Bubble onset time ranged from 5-22 minutes post-chamber and lodge time ranged from 0-70+ minutes. Bubbles were visualized mostly in the arteries of the retinal circulation. Severe vasoconstriction was captured using red-free angiography in two sheep. In two other sheep, fluorescein angiography demonstrated occluded blood flow caused by arterial gas emboli. This study demonstrates that retinal angiography is a practical tool for real-time, noninvasive detection of bubbles in the retinal circulation, a visible window to the cerebral circulation. Thus retinal angiography may prove invaluable in the early detection of arterial gas emboli in the cerebral circulation, the resolution of which is imperative to favorable neurological outcomes. This study also presents for the first time images of bubbles in the retinal circulation associated with DCS captured by a fundus camera.

Can transcranial Doppler discriminate between solid and gaseous microemboli? Assessment of a dual-frequency transducer system.

BACKGROUND AND PURPOSE: Transcranial Doppler ultrasound can reliably detect both gaseous and solid cerebral emboli. However, conventional equipment is unable to discriminate between gaseous and solid emboli. This is a major limitation in situations in which the 2 coexist, because they may have very different clinical relevance. Recently, a novel Embo-Dop system, using insonation at 2 ultrasound transducer frequencies, has been developed. An initial study with a small sample size suggested it provided excellent discrimination. We performed a validation study in subjects with embolic signals of known nature. METHODS: Gaseous embolic signals were obtained in 7 patients with known patient foramen ovale by intravenous injection of agitated saline injections. Solid embolic signals were obtained in patients with symptomatic carotid stenosis (N=23). Discrimination of the 2 using the Embo-Dop system dual-frequency system was assessed. It was compared with discrimination using embolic signal maximum intensity with an intensity threshold. RESULTS: One hundred forty-five solid embolic signals were recorded from carotid stenosis patients. Seventy-three were classified as solid and 72 as gaseous by the Embo-Dop system. Six hundred forty-eight gaseous embolic signals were recorded from 7 patients with patent foramen ovale. Six hundred twenty-five were classified as gaseous and 23 as solid. This gave a sensitivity of 50.3% and specificity of 96.5% for detecting solid embolic signals. Discrimination was better than using a simple intensity threshold. CONCLUSIONS: The Embo-Dop dual-frequency system allows better discrimination than a simple intensity threshold but it is not accurate enough for use in clinical or research studies. Further work is needed to develop reliable clinical systems for discrimination of emboli.