Usefulness of perioperative blood glucose control in patients undergoing off-pump coronary artery bypass grafting

Objective We investigated the usefulness of perioperative blood glucose control in patients undergoing coronary artery bypass grafting (CABG). Methods DM patients were aggressively treated with intensive insulin therapy to achieve a preoperative fasting blood glucose level of 140 mg/dl and a postoperative level of 200 mg/dl. For comparison, patients were divided as follows: (1) DM group vs. non-DM group, and (2) for mean blood glucose level in the intensive care unit (ICU), lower than 200 mg/dl (IL) vs. 200 mg/dl or higher (IH). Results (1) In the DM group, the amount of insulin (U) used during surgery was greater (P < 0.05), and the duration of ICU stay was longer (P < 0.05). The incidence of all complications was higher in the DM group (P < 0.05). (2) Between the IH group (54) and the IL group (82), the proportion of DM patients was higher in the IH group (75% vs. 38%, P < 0.05). In the IH, the duration of ICU stay (P < 0.01) was longer, and the incidence of all complications was higher (P < 0.05). (3) In the DM group, the incidence of complications tended to be higher in the IH group. The incidence of complications was extremely low in the non-DM group. Conclusion Strict perioperative blood glucose control may help to improve the outcomes of CABG.     

Risk factors for prolonged ICU stay in patients following coronary artery bypass grafting with a long duration of cardiopulmonary bypass

Purpose Risk factors for prolonged stay in the intensive care unit (ICU) in patients following coronary artery bypass grafting (CABG) have been reported in many previous studies. However few have focused on circulatory and respiratory status as immediate postoperative risk factors. Therefore we examined immediate postoperative risk factors for prolonged ICU stay after CABG with a long duration of cardiopulmonary bypass (CPB).Methods We studied retrospectively 100 consecutive patients undergoing elective CABG with CPB. Patients were excluded from this study if the duration of aortic cross-clamping was less than 60min. Patients were divided into three groups according to the duration of the ICU stay. Patients in group A (n = 68) were discharged from the ICU on the next morning after surgery, those in group B (n = 19) stayed for 3 days, and group C (n = 13) stayed for more than 3 days. Perioperative variables were compared among the three groups and we demonstrated risk factors for prolonged (more than 3 days) ICU stay.Results There were significant differences in duration of CPB (157 ± 34 versus 184 ± 48 minutes, P < 0.05) and aortic cross-clamping (119 ± 32 versus 141 ± 40min) between groups A and B. On the other hand, there were significant differences in age (62.8 ± 7.8 versus 67.4 ± 6.2 years), mean pulmonary artery pressure (MPAP) (17 ± 2 versus 22 ± 3mmHg), and Pa_{O 2}/FI _{O 2} (PF ratio) (409 ± 94 versus 303 ± 108mmHg) on admission to the ICU between groups A and C. There were no significant differences in intraoperative fluid balance and duration of CPB. Multiple logistic regression analysis identified age (>65 years), MPAP (>21mmHg), and PF ratio (<300mmHg) as independent risk factors for more than a 3-day ICU stay.Conclusion Advanced age, increased MPAP, and decreased PF ratio on admission to the ICU were significant risk factors for a prolonged ICU stay of more than 3 days.     

Effects of lumbar puncture position on arterial blood gases

We observed the changes in partial pressure of arterial oxygen (Pao ₂) and carbon dioxide (Paco ₂) before and during assumption of the lateral position prior to lumbar puncture in 81 patients to investigate whether lung volume decreased and ventilation was suppressed. Pao ₂ significantly decreased while the patients were in the lateral position, while Paco ₂ remained unchanged. There was a negative correlation between the change in Pao ₂ and age [change in Pao ₂ (mmHg)=−0.13×age (years)+4.28,P<0.01]. The fact that closing volume increases with age implies that the decrease in functional residual capacity in the lateral position could have caused the decrease in Pao ₂. It is therefore advisable to continuously monitor arterial oxygenation using a noninvasive monitor, such as a pulse oximeter, while performing spinal or epidural block, especially in elderly patients.     

Pulse Oximetry Declines Due To Intradermal Isosulfan Blue Dye: A Controlled Prospective Study

Background: Isosulfan blue dye is widely used in sentinel node surgery for malignant melanoma. Intravascular dye injection is known to interfere with pulse oximetry (Spo₂), but the effects of intradermal dye injection are not well known. Our aim was to determine the effects of intradermal dye injection on Spo₂.Methods: This was a controlled, prospective study of 84 consecutive patients undergoing wide local excision of malignant melanoma and sentinel lymph node biopsy. The control group (n = 24) received no dye. The dye group (n = 60) received isosulfan blue dye intradermally at the biopsy site. Spo₂ declines of 2% were considered significant.Results: Two patients in the control group (8%) and 20 patients in the dye group (33%) had a clinically significant Spo₂ decline (P < .02). In those with significant declines in the dye group, the amount ranged from 2% to 4%. The latency of decline from the time of injection was 22.8 ± 12.7 minutes.Conclusions: Patients who receive intradermal dye injection for sentinel lymph node surgery have a 4-fold increased rate of developing declines in Spo₂. With the increasing trend toward using intradermal dye administration to map lymphatic drainage in melanoma and breast surgery, declines in Spo₂ readings can be expected to occur frequently. To our knowledge, this is the first report of the effects of intradermal dye injection on Spo₂ readings in a large series of patients.     

Hemodynamic and Respiratory Effects of Robot-assisted Laparoscopic Fundoplication in Children

Laparoscopic fundoplication is increasingly used for treating gastro-esophageal reflux disease in children. Mechanical and pharmacological effects may contribute to hemodynamic and respiratory changes during carbon dioxide pneumoperitoneum. The aim of the present study was to evaluate the hemodynamic and respiratory effects of pneumoperitoneum (PP) with an intra-abdominal pressure (IAP) of 12 mmHg in children undergoing robot-assisted laparoscopic fundoplication during total intravenous anesthesia. Ten children, aged 8–16 years, American Society of Anesthesiologists physical status II–III, scheduled for robot-assisted laparoscopic fundoplication in the reverse Trendelenburg position were investigated. Minute ventilation (MV), peak inspiratory pressure (PIP), IAP, heart rate (HR), mean arterial blood pressure (MAP) were recorded, together with pH, base excess, HCO₃⁻, P_etCO₂, P_aCO₂, and P_aO₂ at six time points: before insufflation, 10, 30, 60, 90 minutes after creating PP and after desufflation. The IAP was maintained at 12 mmHg. During insufflation MAP increased significantly from 70.6 (±9.0) to 84.8 (±10.4) mmHg, MV was increased from 4.6 (±0.8) to 5.5 (±0.9) lmin⁻¹, PIP increased, P_aO₂ and pH decreased. P_etCO₂ increased from 33.1 (±1.6) to 36.6 (±1.6) mmHg together with P_aCO₂. Hemodynamic and respiratory effects due to the intra-abdominal insufflation of CO₂ with an IAP of 12 mmHg are well tolerated, and anesthesia with remifentanil, propofol and mivacurium facilitates extubation immediately at the end of surgery.     

Distributions of Microdamage Are Altered Between Trabecular Rods and Plates in Cancellous Bone From Men With Type 2 Diabetes Mellitus

Individuals with type 2 diabetes mellitus (T2DM) have an increased risk of fragility fracture despite exhibiting normal to high bone mineral density (BMD). Conditions arising from T2DM, such as reduced bone turnover and alterations in microarchitecture, may contribute to skeletal fragility by influencing bone morphology and microdamage accumulation. The objectives of this study were (i) to characterize the effect of T2DM on microdamage quantity and morphology in cancellous bone, and (ii) relate the accumulation of microdamage to the cancellous microarchitecture. Cancellous specimens from the femoral neck were collected during total hip arthroplasty (T2DM: n = 22, age = 65 ± 9 years, glycated hemoglobin [HbA1c] = 7.00% ± 0.98%; non-diabetic [non-DM]: n = 25, age = 61 ± 8 years, HbA1c = 5.50% ± 0.4%), compressed to 3% strain, stained with lead uranyl acetate to isolate microdamage, and scanned with micro–computed tomography (μCT). Individual trabeculae segmentation was used to isolate rod-like and plate-like trabeculae and their orientations with respect to the loading axis. The T2DM group trended toward a greater BV/TV (+27%, p = 0.07) and had a more plate-like trabecular architecture (+8% BV_plates, p = 0.046) versus non-DM specimens. Rods were more damaged relative to their volume compared to plates in the non-DM group (DV_rods/BV_rods versus DV_plates/BV_plates: +49%, p < 0.0001), but this difference was absent in T2DM specimens. Longitudinal rods were more damaged in the non-DM group (DV_{longitudinal rods}/BV_{longitudinal rods}: +73% non-DM versus T2DM, p = 0.027). Total damage accumulation (DV/BV) and morphology (DS/DV) did not differ in T2DM versus non-DM specimens. These results provide evidence that cancellous microarchitecture does not explain fracture risk in T2DM, pointing to alterations in material matrix properties. In particular, cancellous bone from men with T2DM may have an attenuated ability to mitigate microdamage accumulation through sacrificial rods. © 2022 American Society for Bone and Mineral Research (ASBMR).     

Jugular Venous Oxygen Saturation During Mild Hypothermic Versus Normothermic Cardiopulmonary Bypass in Elderly Patients

Purpose. Age is known to be a major risk factor for adverse postoperative cognitive dysfunction after cardiac surgery. We conducted this study to determine if jugular venous oxygen saturation (SjvO₂) differed during mild hypothermic (32°C) and normothermic cardiopulmonary bypass (CPB) in elderly patients.Methods. Sixty patients aged over 70 years who underwent elective coronary artery bypass grafting were randomly divided into two groups. Group 1 (n = 30) underwent normothermic CPB (>35°C) and group 2 (n = 30) underwent mild hypothermic CPB (32°C). For the continuous monitoring of SjvO₂, a fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb after the induction of anesthesia. Hemodynamic parameters, and arterial and jugular venous blood gases were measured at seven time points.Results. The SjvO₂ in the normothermic group was lower at the onset of CPB and 20min after the onset, than from the time of induction of anesthesia until the start of surgery (period 1), the respective SjvO₂ values being 50.3% ± 1.0%, 50.1% ± 1.6%, and 59.5% ± 1.9% (P < 0.05). However, in the mild hypothermic group there were no changes in the SjvO₂ value throughout the study. The cerebral desaturation time (when the SjvO₂ value was <50%) and the ratio of the cerebral desaturation time to the total CPB time in the normothermic group differed significantly from those in the hypothermic group, being 19 ± 11min and 17% ± 10%, and 9 ± 3min and 8% ± 4%, respectively (P < 0.05).Conclusions. The SjvO₂ value was better during mild hypothermic CPB than during normothermic CPB in elderly patients.     

The production and clearance of endothelin and its influence on kidney function after liver transplantation in rats

To assess the involvement of endothelin-1 (ET-1) in rat liver allograft rejection, we evaluated ET-1 expression in tissues obtained from BN (RT1ⁿ) to BN rats (group 1), and DA (RT1^a) to BN rats (group 2). The ET-1 levels in group 1, determined by radioimmunoassay, remained low in the serum, liver, and bile, but in group 2, they peaked on postoperative day (POD) 5 in the liver, kidney, bile, and urine, at 344 ±31.6pg/gwet, 306 ± 97.4pg/gwet, 1008 ± 258 pg/day, and 156 ± 45 pg/day, respectively, whereas levels in the serum peaked on POD 7 at 38.7 ± 13.1 pg/ml. In the portal vein (PV) ET-1 showed extremely high levels without statistical difference between groups 1 and 2, at 93.0 ± 15.5, and 83.0 ± 9.84 pg/ml on POD 7, respectively. However, in the suprahepatic vena cava (SHVC) and the abdominal aorta (AO), the ET-1 levels were statistically higher in group 2 compared to group 1 (P < 0.01). Immunohistochemical staining showed decreased staining of the liver and kidney in group 2 on POD 7. In conclusion, increasing levels of ET-1 were released from the liver and kidney during the early stage of rejection, resulting in the high ET-1 levels in these tissues, which were cleared promptly. However, an increased production of ET-1 was not observed in association with the release of ET-1.     

PREDICTING HEALING OF LOWER LIMB ULCERS

Management of ischaemic ulcers in patients with compromised peripheral arterial circulations relies on the physical examination and the simple, non-invasive assessment of arterial supply. This study aims to determine if transcutaneous oxygen pressure (tcPo₂) measurement can improve management decisions based on ankle or toe systolic blood pressure measurement. Twenty-two consecutive patients with ischaemic ulcers had tcPo₂, measured and the ankle/brachial (ABI) and toe/brachial (TBI) indices calculated. Two months after surgery 12 of 22 (55%) ulcers were healing and 10 (45%) were indolent. Postoperative tcPo₂ values were predictive of wound outcome (P <0.001). A tcPo₂^> 31 mmHg was invariably associated with healing whilst a tcPo₂, 28 mmHg was associated with indolence. Anklebrachial indices and TBI were unable to be calculated in all patients due to falsely elevated pressures and hallux amputations, respectively, and neither was predictive of outcome (ABI P= 0.152, TBI P = 0.069). The response to revascularization was less in diabetic patients with a mean tcPo₂ increase of 18 mmHg compared to non-diabetic patients with a mean tcPo₂ increase of 37 mmHg. TcPo₂ measurement appears to be a reliable technique that can influence ischaemic ulcer management.     

Factors Associated with Postoperative Cognitive Dysfunction in Patients Undergoing Cardiac Surgery

Purpose Central nervous system complications continue to be major causes of morbidity and mortality after cardiac surgery. The purpose of this study was to identify the risk factors for postoperative cognitive dysfunction after coronary artery bypass graft (CABG) surgery. Methods Eighty-eight patients scheduled for elective CABG were studied. After the induction of anesthesia, a fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb for the continuous monitoring of jugular venous oxygen hemoglobin saturation (SjvO₂). The hemodynamic parameters and arterial and jugular venous blood gases were measured during cardiopulmonary bypass (CPB). All patients underwent a battery of neurological and neuropsychological tests one day before the operation and at 6 months after the operation. Results The incidence of a cognitive decline at 6 months was 24/88 (27.3%). Greater age (P = 0.04), the presence of renal failure (P < 0.001), and diabetes mellitus (P < 0.001) were more frequent in the patients with postoperative cognitive dysfunction at 6 months after the operation than in patients without cognitive dysfunction. Age (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.0–1.7; P = 0.04), diabetes mellitus (OR, 1.8; 95% CI, 1.2–2.4; P < 0.01), and presence of renal failure (OR, 2.8; 95% CI, 2.4–4.3; P < 0.01) were associated with cognitive impairment at 6 months postoperatively. However, there was no relationship between the presence of atherosclerosis in the ascending aorta and postoperative cognitive dysfunction after CABG surgery. Conclusions A greater age, diabetes mellitus, and renal failure were found to be risk factors for development of cognitive impairment at 6 months after CABG with CPB.     

Altered Tissue Composition,Microarchitecture, and Mechanical Performance in Cancellous Bone From Men With Type 2 Diabetes Mellitus

People with type 2 diabetes mellitus (T2DM) have normal-to-high BMDs, but, counterintuitively, have greater fracture risks than people without T2DM, even after accounting for potential confounders like BMI and falls. Therefore, T2DM may alter aspects of bone quality, including material properties or microarchitecture, that increase fragility independently of bone mass. Our objective was to elucidate the factors that influence fragility in T2DM by comparing the material properties, microarchitecture, and mechanical performance of cancellous bone in a clinical population of men with and without T2DM. Cancellous specimens from the femoral neck were collected during total hip arthroplasty (T2DM: n = 31, age = 65 ± 8 years, HbA1c = 7.1 ± 0.9%; non-DM: n = 34, age = 62 ± 9 years, HbA1c = 5.5 ± 0.4%). The T2DM specimens had greater concentrations of the advanced glycation endproduct pentosidine (+ 36%, P < 0.05) and sugars bound to the collagen matrix (+ 42%, P < 0.05) than the non-DM specimens. The T2DM specimens trended toward a greater bone volume fraction (BV/TV) (+ 24%, NS, P = 0.13) and had greater mineral content (+ 7%, P < 0.05) than the non-DM specimens. Regression modeling of the mechanical outcomes revealed competing effects of T2DM on bone mechanical behavior. The trend of higher BV/TV values and the greater mineral content observed in the T2DM specimens increased strength, whereas the greater values of pentosidine in the T2DM group decreased postyield strain and toughness. The long-term medical management and presence of osteoarthritis in these patients may influence these outcomes. Nevertheless, our data indicate a beneficial effect of T2DM on cancellous microarchitecture, but a deleterious effect of T2DM on the collagen matrix. These data suggest that high concentrations of advanced glycation endproducts can increase fragility by reducing the ability of bone to absorb energy before failure, especially for the subset of T2DM patients with low BV/TV. © 2019 American Society for Bone and Mineral Research.     

Intramyocardial partial oxygen pressure in patients undergoing transmyocardial laser revascularization and bypass surgery

Objective—Numerous investigations could not clarify the exact mechanism of transmyocardial laser revascularization (TMLR). The aim of this study was to investigate, whether TMLR leads to an increase of myocardial oxygenation in comparison to patients undergoing coronary artery bypass grafting (CABG).

Design—Twelve patients (TMLR group) underwent TMLR alone with an 800?W CO ₂ laser through a left anterior thoracotomy. Seventeen patients (CABG group) underwent standard CABG. Myocardial oxygenation was determined by measuring intramyocardial partial oxygen pressure (p _ti O ₂ ). P _ti O ₂ was measured online and mean values at 1,?24,?32, and 48?h postoperatively were compared with baseline before intervention. Parameters influencing p _ti O ₂ (arterial pO ₂ , hemodynamic parameters, hemoglobin) were recorded.

Results—Mean baseline p _ti O ₂ was significantly lower in the TMLR group compared with the CABG group (p?<?0.05). In both groups p _ti O ₂ increased significantly in the postoperative course, whereby p _ti O ₂ in the TMLR group was significantly lower compared with the CABG group.

Conclusion—Although the exact mechanism of action of TMLR remains unclear, p _ti O ₂ and thus oxygen supply in the myocardium increased in patients undergoing TMLR at least in the early postoperative course. However, p _ti O ₂ increased to a lesser extent compared with CABG.     

Anesthesia for liver transplantation in patients with arterial hypoxemia

Arterial oxygenation during anesthesia and time of postoperative mechanical ventilation were investigated in 17 patients with chronic liver disease who underwent liver transplantation. Six patients had arterial hypoxemia (PaO₂ 64±3 mmHg) and the other 11 patients had normal PaO₂ (105±5 mm Hg) before transplantation. None of the patients were smokers and all had normal preoperative pulmonary X-ray and spirometry. During transplantation, PaO₂ increased in both groups, but PaO₂ was still approximately 20% lower and PA-aO₂ was 40%–60% higher in the hypoxemic group than in the normoxemic patients (P<0.05). The median postoperative time on mechanical ventilation was three times longer in the hypoxemic group (56 h) than in the normoxemic patients (18 h; P=NS). Number or severity of postoperative complications and outcome did not differ between the two groups. It is therefore suggested that patients with arterial hypoxemia without overt lung disease should also be accepted for liver transplantation.     

Elevated glycosylated haemoglobin (HbA1c) is a risk marker in coronary artery bypass surgery

Objective. To evaluate if glycosylated haemoglobin 1 (HbA_1c) was associated with increased risk of infection and mortality after coronary artery bypass grafting (CABG). Design. Prospective observational study. Preoperative HbA_1c concentrations were correlated to outcome in patients followed for an average of 3.5 years after CABG. Results. HbA_1c was ≥6% in 68% of 161 patients with diabetes mellitus (DM) and in 3% of 444 patients without DM. Superficial sternal wound infection was observed in 13.9% if HbA_1c ≥6% versus in 5.5% if <6% (p=0.007). Mediastinitis occurred in 4.9% if HbA_1c≥6% and in 2.1% if HbA_1c<6% (p=0.20) (Hazard ratio (HR) 1.9, 95% CI 0.6-5.9). Follow-up mortality was 18.9% in patients with HbA_1c≥6% compared to 4.1% if HbA_1c<6% (p<0.001) with HR 5.4, (95% CI 3.0-10.0) after multivariable adjustment. The risk of death was similar regardless of DM diagnosis. Conclusions. HbA_1c ≥6% was associated with an increased risk of postoperative superficial sternal wound infections and a trend for higher mediastinitis rate and significantly higher mortality three years after CABG.     

Post-transplant diabetes mellitus: risk factors, frequency of transplant rejections, and long-term prognosis

Background Estimates of the incidence of new-onset diabetes after renal transplantation vary between 2% and 54%. It was the aim of the present trial to study the prevalence of post-transplant diabetes mellitus (DM), the risk factors, the frequency of transplant rejections, and the long-term prognosis.Methods We studied all consecutive patients with endstage renal disease, but without DM who received kidney transplantation at our center since 1992 (n = 253; age, 52.2 ± 12.6 years; body mass index, 22.0 ± 7.9 kg/m²). Follow up was 3.3 ± 1.6 years (range, 0.1–17.7) years.Results In total, 43/253 patients (17%) developed new-onset DM after transplantation. Patients with new-onset diabetes were significantly older (58.3 ± 11.4 vs 50.9 ± 12.5 years; P < 0.01) and had a tendency to a higher body mass index (24.0 ± 8.5 vs 21.6 ± 7.8 kg/m²; P = 0.077). There were no differences between the groups in respect of blood pressure control (137.7 ± 19.0/81.8 ± 14.2 vs 137.1 ± 21.9/83.9 ± 13.1 mmHg; P = 0.89/0.39), glomerular filtration rate (58.0 ± 28.1 vs 64.1 ± 22.1 ml/min per 1.73 m²; P = 0.13), steroid dosage (4.5 ± 1.2 [n = 21] vs 4.6 ± 2.2 [n = 135] mg/day; P = 0.13), or the frequency and dosage of immunosuppressive drugs such as cyclosporine, tacrolimus, and sirolimus during the follow up. However, more patients with post-transplant diabetes received steroids (83.7% vs 64.3%; P = 0.021) and azathioprine (41.9% vs 24.3%; P = 0.030). Patients with new-onset diabetes had higher serum creatinine values (163.4 ± 67.9 vs 138.7 ± 59.5 µmol/l; P = 0.017). The mean hemoglobin (Hb)A1c in patients with DM was 6.28 ± 1.29% (Tosho HPLC; mean normal, 5.15%). In 18 patients (7.1%) transplant rejections occurred (16 patients without DM [7.6%] vs 2 patients with new-onset DM [4.7%]; P = 0.39). On performing multivariate analysis, the only parameter found to be associated with new-onset DM was the body mass index (R² = 0.05; β = 0.23; P = 0.02), and the only factor associated with transplant rejection was fasting blood glucose (R² = 0.07; β = 0.28; P = 0.02). None of the other parameters included in the models (age, duration after transplantation, diabetes duration, immunosuppressive therapy, HbA1c, HLA mismatches) showed any associations.Conclusions The prevalence of new-onset DM after renal transplantation was 17%. The most important parameter associated with new-onset diabetes was a higher body mass index, and the most important parameter associated with transplant rejection was an elevated fasting blood glucose level. To prevent transplant rejections and to improve patients’ outcome, in addition to providing optimal immunosuppressive therapy and HLA matching, good blood pressure control and HbA1c, but also near normal fasting blood glucose levels, should be achieved.     

Preoperative Spirometry Versus Expired Gas Analysis During Exercise Testing as Predictors of Cardiopulmonary Complications After Lung Resection

Purpose As cardiopulmonary load increases with the amount of lung resected, to perform surgery safely it is important to be able to predict cardiopulmonary insufficiency. However, lung function testing with spirometry and blood gas analysis does not accurately measure cardiopulmonary reserve. We conducted this study to evaluate expired gas analysis during exercise testing for predicting postoperative complications after lung resection.Methods Expired gas analysis during exercise and spirometry were done 1 week preoperatively in 211 patients who underwent pulmonary resection for lung cancer. Patients were divided postoperatively according to whether cardiopulmonary complications were absent (group A) or present (group B).Results In group B there were more men than women (P < 0.01), and the mean age was greater (P < 0.05). There was no difference in disease stage, but more patients underwent pneumonectomy in group B than in group A (P < 0.005). The results of expired gas analysis during exercise testing and of spirometry showed that maximum oxygen uptake/m² (P < 0.0005), anaerobic threshold/m² (P < 0.01), vital capacity (VC)/m² (P < 0.005), %VC (P < 0.0001), forced expiratory volume in 1s (FEV_1.0)/m² (P < 0.0001), and FEV_1.0% (P < 0.05) were lower in group B than in group A.Conclusions The combination of expired gas analysis during exercise and conventional pulmonary function tests identified patients at risk for postoperative cardiopulmonary complications following pulmonary resection.     

Oxygen delivery and consumption in the perioperative period of coronary artery bypass grafting without blood transfusion

The perioperative changes in relationship between oxygen delivery (D¨_{O 2}) and oxygen consumption (V¨_{O 2}) were examined in forty patients who underwent coronary artery bypass grafting (CABG) without blood transfusion. Hemodilution was performed to maintain hematocrit of 19.2 ± 1.8% during cardiopulmonary bypass (CPB). Hemodynamic and metabolic parameters were measured in four stages; before CPB (stage I), after CPB (stage II), after ICU arrival (stage III), and the following day (stage IV). In each stage, there was a strong positive correlation between V¨_{O 2} and D¨_{O 2}. In stage I, a decrease in D¨_{O 2} was met with low V¨_{O 2}, and there was no imbalance between them (r = 0.67, P 0.01). V¨_{O 2} increased significantly in stage II, and this increased V¨_{O 2} was compensated by an increase in D¨_{O 2} sufficiently to meet tissue oxygen demand (r = 0.59, P 0.01). In stage III and IV, the increases in tissue oxygen requirements were met by increases in oxygen extraction ratio (r = 0.81, P 0.01, r = 0.60, P 0.01, respectively) reflected in lowered mixed venous oxygen tension and saturation. From these results, it is assumed that the adequate relationship between V¨_{O 2} and D¨_{O 2} can be maintained in the perioperative period of CABG without blood transfusion.(Mizushima A, Niimi Y: Oxygen Delivery and consumption in the perioperative period of coronary artery bypass grafting without blood Transfusion. J Anesth 4: 313–318, 1990)     

Donor diabetes mellitus is a risk factor for diminished outcome after liver transplantation: a nationwide retrospective cohort study

With the growing incidence of diabetes mellitus (DM), an increasing number of organ donors with DM can be expected. We sought to investigate the association between donor DM with early post-transplant outcomes. From a national cohort of adult liver transplant recipients (1996–2016), all recipients transplanted with a liver from a DM donor (n = 69) were matched 1:2 with recipients of livers from non-DM donors (n = 138). The primary end-point included early post-transplant outcome, such as the incidence of primary nonfunction (PNF), hepatic artery thrombosis (HAT), and 90-day graft survival. Cox regression analysis was used to analyze the impact of donor DM on graft failure. PNF was observed in 5.8% of grafts from DM donors versus 2.9% of non-DM donor grafts (P = 0.31). Recipients of grafts derived from DM donors had a higher incidence of HAT (8.7% vs. 2.2%, P = 0.03) and decreased 90-day graft survival (88.4% [70.9–91.1] vs. 96.4% [89.6–97.8], P = 0.03) compared to recipients of grafts from non-DM donors. The adjusted hazard ratio for donor DM on graft survival was 2.21 (1.08–4.53, P = 0.03). In conclusion, donor DM is associated with diminished outcome early after liver transplantation. The increased incidence of HAT after transplantation of livers from DM donors requires further research.     

Effects of hypothermia in hypercapnia and hypercapnic hypoxemia

Anesthetized, paralyzed and mechanically ventilated pigs were hypoventilated to extrene hypercapnia (Paco₂?20 kPa) at Fio₂ 0.5, and allotted to a hypothermic group (31.5 ±0.l°C, n = 6) or a control group (39.6±0.2°C, n = 6). Compared with the controls, the hypothermic animals had higher Pao₂ (19.2 vs 15.6 kPa, P>0.05), Sao₂ (97.2 vs 89.3%), Sv?o₂ (78.7 vs 68.2%), end-tidal 0₂ (34.5 vs 24.8 kPa) and arterial pH (7.01 vs 6.91), (P>0.01), but lower Pv?o₂ (7.0 vs. 10.2 kPa) and Paco₂ (13.2 vs 23.5 kPa), (P>0.01). Hypothermia reduced O₂ delivery (Do₂), O₂ consumption (Vo₂) and CO₂ production by 40–45% (P> 0.05), but O₂ extraction ratio, i.e. VO₂, Do₂-¹. 100 (%), did not differ between groups. Hypothermic animals had lower heart rate (127 vs 223 beats.min-¹, P>0.05) and cardiac output (2.5 vs 3.9 l.min-¹, P>0.01). Subsequently, the inspired oxygen fraction (Fio₂) was decreased stepwise (0.3, 0.25, 0.21, 0.15, 0.10) at 30- min intervals. At Fio₂ 0.3, the hypothermic group had higher Pao₂ (10.0 vs 5.7 kPa), Sao₂ (91.3 vs 28.5%), Pv?o, (5.8 vs 3.4 kPa), Sv?o₂ (70.7 vs 10.3%), end-tidal O₂ (16.7 vs 8.5 kPa), O₂ delivery (344 vs 155 ml.min-¹), arterial pH (7.02 vs 6.94) and systemic vascular resistance (3850 vs 1652 dyn.s. cm-⁵(38500 vs 16520 μN. s. c m-⁵)) compared with the controls (P>0.01), while Paco₂ was lower (12.4 vs 22.7 kPa), as well as O₂ extraction ratio (23 vs 63%) and O₂ half saturation tension (4.3 vs 8.0 kPa) (P>0.01). Except for Pao₂, all differences between groups remained significant at Fio₂ 0.25. The control animals died during Fio₂ 0.25 and 0.21, while all hypothermic animals remained circulatorily stable. One hypothermic animal died after 12 min at Fio₂ 0.15 and the remainder after 6–39 min (mean 22 min) at Fio₂ 0.10. We conclude that hypothermia markedly improves whole-body oxygen balance, cardiovascular stability and survival in hypercapnic hypoxemia.     

Sodium-phosphate transport in the kidney and intestine of the hypophosphatemic mouse

X-linked hypophosphatemic vitamin D-resistant rickets is the most common inherited form of vitamin D-resistant rickets in man. The current studies were designed to characterize the defect in the sodium (Na⁺)-phosphate transporter in the (Hyp) mouse model. The slope of initial rate of phosphate uptake was significantly decreased in the kidney but not in intestinal brush border membranes of the (Hyp) mice compared with genetically matched controls. Phosphate uptake by the basolateral membranes of the intestine and kidney was similar in the (Hyp) and control mice. Kinetic analysis of phosphate uptake by renal brush border membranes showed aV _max of 0.32±0.06 and 1.6±0.1 nmol/mg protein per 15 s (P<0.01) andK _m of 0.07±0.06 and 0.39±0.05 mM in (Hyp) and control mice respectively (P<0.05).V _max andK _max of jejunal uptake of phosphate were similar in (Hyp) and control mice. To confirm these findings, we expressed the Na⁺-phosphate transporter inXenopus laevis oocytes. Na⁺-dependent phosphate uptake in the oocytes was expressed 6 days after renal and intestinal poly(A)⁺ RNA injection, however, uptake values were significantly lower in oocytes injected with renal poly(A)⁺ RNA from the (Hyp) mice compared with controls (P<0.01). No differences were noted in phosphate uptake by oocytes injected with poly(A)⁺ RNA from the jejunum of the (Hyp) or control mice. These studies suggest that the defect in the (Hyp) mice is localized to the kidney and is secondary to diminished activity and/or function of the Na⁺-phosphate transporter.