Spontaneous breathing and total body oxygen consumption in children recovering from open-heart surgery.

The effects of withdrawal of ventilatory support on cardiopulmonary function, oxygen consumption and carbon dioxide production were assessed in 25 infants and children within seven days (2.9 +/- 2.5 days; mean +/- SD) of an open heart operation, during weaning from ventilatory support. The average age of the patients was 3.4 +/- 3.5 years and weight 12.4 +/- 8.3 kg. Heart rate, blood pressure, arterial and central venous blood gas values, and oxyhemoglobin saturations were measured during controlled mechanical ventilation and during spontaneous breathing with continuous positive airway pressure. Simultaneously, VO2 and VCO2 were measured using indirect calorimetry. Withdrawal of ventilatory support effected an expected, significant decrease in arterial pH (7.42 +/- 0.10 to 7.37 +/- 0.06; p less than 0.001) and an increase in PaCO2 (34 +/- 6 to 40 +/- 5 mm Hg; p less than 0.0001), while arterial blood oxyhemoglobin saturation, heart rate, and blood pressure remained unchanged. A significant increase in central venous oxyhemoglobin saturation (67.9 +/- 11.9 to 74.8 +/- 8.3 percent; p less than 0.001) indicated improvement in systemic blood flow during spontaneous breathing. Average VO2 and VCO2 did not change significantly. A decrease in VO2 by more than 5 percent was seen in seven patients, an increase by more than 5 percent in nine, and a change within +/- 5 percent in nine patients. The change in VO2 was inversely related to the difference between measured and expected VO2 during mechanical ventilation (r = -0.73) and to body temperature (r = -0.69). The results indicate that factors other than the oxygen uptake by the respiratory muscles may have significant effects on total body VO2 in infants and children after open-heart surgery. Therefore, monitoring of VO2 during withdrawal of ventilatory support may not be an accurate indicator of respiratory work and oxygen cost of breathing in these patients.

Candida immunity in patients undergoing surgical treatment for heart valve disease.

The appearance of Candida antigen (Latex agglutination method), Candida antibodies (indirect immunofluorescence) and positive fungal cultures as well as the lymphocyte transformation response to Candida antigen "in vitro" was studied in a series of 37 successive patients before and after heart valve replacement. The Candida antigen test was positive preoperatively in 11/36 (31%) and postoperatively in 14/36 (39%) of the patients and in 2/200 (1%) of the controls (blood donors). The differences in the frequencies of positive tests between the patient group and the control group are significant (p less than 0.001). The lymphocyte response to Oidiomycin (Candida albicans) preoperatively was greater than the mean control value in 6/11 (54.5%) of the patients showing a positive Candida antigen test, but only in 4/25 (16.0%) of the patients who were Candida antigen negative. The total number of lymphocytes and the number of ANAE positive (T) cells as well as the lymphocyte response to Oidiomycin (OID), tuberculoprotein (PPD) and phytohaemagglutinin (PHA) decreased markedly postoperatively. Candida antibody titres were positive (greater than or equal to 1:128) in 3/37 (8%) of the postoperative patients and in 2/84 (2.4%) of the controls. This difference is not significant. Positive Candida antibody titres were found postoperatively in 15/37 (41%) of the patients, which is a significantly higher frequency than that seen preoperatively (p less than 0.005). More positive fungal cultures from throat specimens (p less than 0.005) were found in the patient group before surgery than in the control group (hospital personnel). After surgery the number of positive fungal cultures in these cases decreased (p less than 0.001) due to the use of oral antifungal prophylaxis with nystatin tablets.(ABSTRACT TRUNCATED AT 250 WORDS)

[Magnetic resonance imaging in musculoskeletal tuberculosis]. / Magnetisk resonans-scanning ved muskuloskeletal tuberkulose.

The incidence of tuberculosis in Denmark has increased over the last years. Two cases of primary osteoarticular tuberculosis are described: tuberculous ostitis of the scapula and surrounding soft tissue, and tuberculosis of the elbow. We have emphasized the appearance on magnetic resonance imaging (MRI), as the role of this modality has only been sporadically described for osteoarticular tuberculosis in areas other than the vertebral column. The cases show that MRI can contribute to a more precise determination of the extent of osteoarticular tuberculosis and its soft tissue involvement.

Cutaneous heat loss in children during anaesthesia.

We have measured non-evaporative, cutaneous heat loss using heat flux transducers at eight skin sites in five children during anaesthesia and compared the data with basal metabolic heat production. The effect of disposable surgical covering and a radiant heater on heat flux was examined. The mean total heat flow rate before draping was 3-9 W higher than the basal metabolic rate after induction of anaesthesia with a simultaneous decrease in rectal temperature. Mean cutaneous heat loss was 62 (SD 9) W m-2 (9.5 (2.1) kJ kg-1 h-1) in children older than 1 yr and 84 W m-2 (17.2 kJ kg-1 h-1) in a 3-month-old infant. Disposable drapes diminished cutaneous heat loss by 29% and a radian heater by 77%. Heat conduction to the mattress was 21 (7) W m-2. These results showed that the decrease in core temperature after induction of anaesthesia was genuine cooling, that is heat loss exceeded heat production.

Oxygen consumption following pediatric cardiac surgery.

Metabolic responses during recovery from cardiac operations for various congenital heart defects were studied in 30 mechanically ventilated pediatric patients in two groups: infants 1 year or less (group I) and children more than 1 year old (group II). Oxygen consumption (VO2) and carbon dioxide production (VCO2) were measured using a pediatric metabolic monitor intermittently after induction of anesthesia, after skin closure, 2 to 4 hours postoperatively, and on the first postoperative morning in the pediatric intensive care unit. Energy expenditure and respiratory quotient were determined from respiratory gas measurements. Rectal and skin temperatures and hemodynamic variables were recorded at the same time. VO2 increased during rewarming 2 to 4 hours after the operation by 12 +/- 15% in group I and by 24 +/- 19% in group II, while rectal temperature increased by 2.0 +/- 1.2 degrees C and 1.8 +/- 1.4 degrees C, respectively. No further increase in VO2 occurred until the first postoperative morning. A hypermetabolic response was not seen in all cases despite marked thermal changes. High-dose fentanyl anesthesia partly explains the low responses. On the other hand, low cardiac output may also compromise oxygen supply. Sixty-three percent of infants were treated for cardiac failure before surgery and 75% needed inotropic support immediately after the operation. Low central venous oxyhemoglobin saturation values (ScvO2 < 60%) were observed during rewarming, indicating an increase in oxygen extraction secondary to an increased oxygen demand in the brain during recovery from anesthesia, and a low cardiac output or delayed restoration of cerebral blood flow after CPB and deep hypothermia.

Calculation of mean skin temperature and changes in body heat content during paediatric anaesthesia.

Mean skin temperature and changes in body heat content were calculated in several different ways from measurements made in five children during operation. Mean skin temperatures were calculated from 162 sets of measurements using 15, 12, eight, seven and four skin sites with various formulae modified according to age. The results of other formulae were compared with age-adjusted, area-weighted 15-site mean skin temperature which was used as a reference. Changes in body heat content were calculated from Burton's equation in different ways and errors from different variables in the formula were evaluated. Mean skin temperature from 12 skin sites was within 0.5 degrees C of the 15-point reference method, and that from four sites within 1 degree C. The core temperature selected and the weighting coefficients used in calculating mean body temperature were more important sources of error in the determination of change in body heat content than was mean skin temperature.

Preoperative timolol and ocular compression in cataract surgery.

The intraocular pressure (IOP) reducing effect of topical timolol with digital ocular compression for the prevention of vitreous loss in cataract surgery was compared with the effect of combined acetazolamide-mannitol pre-medication with digital compression. In the timolol group of 30 patients the mean IOP reduced from 11.4 mmHg before the compression to 8.2 mmHg after it. In the acetazolamide-mannitol group of 29 patients the mean IOPs were 10.9 and 5.6 mmHg, respectively. The reduction of IOP was statistically highly significant in both groups. There was no case of vitreous loss and the post-operative healing was uncomplicated in both groups of patients. The application of timolol was easy and time saving, but acetazolamide-mannitol pre-medication created deeper hypotony after ocular compression, which was probably due to the vitreous reducing effect of mannitol.

Metabolic effects of corrective surgery in infants and children with congenital heart defects.

We have measured oxygen consumption and carbon dioxide production by indirect calorimetry in 25 infants and children immediately before and after surgical correction of congenital cardiac malformations. Surgical correction of the cardiac defect caused a decrease in oxygen consumption towards normal. Greatly increased oxygen consumption values were observed before surgery in the infants with a large left-to-right intracardiac shunt and heart failure and the highest reduction in metabolic rate, up to 43%, was observed in these infants. The results indicate that corrective surgery for congenital cardiac malformations reduces the load on the cardiopulmonary system immediately after operation.

Postoperative pain relief in children. A comparison between caudal bupivacaine and intramuscular diclofenac sodium.

Two hundred and fifty children undergoing herniotomy or orchidopexy under general anaesthesia were randomly allocated to receive pre-operatively either diclofenac sodium 1 mg.kg-1 given intramuscularly or a caudal injection of bupivacaine 0.25% 1 ml.kg-1 with or without adrenaline or no analgesia. Plasma diclofenac and beta-endorphin concentrations were determined in eight and 21 patients respectively. Postoperative pain was assessed by ward nurses who were blinded to the group allocation. Comparison with the control group showed diclofenac to be an effective analgesic. Caudal bupivacaine provided more pain-free children during the early postoperative hours, but later the need for pethidine as rescue analgesic was lower among the children who had received intramuscular diclofenac. Caudal analgesia abolished the stress-induced increase in plasma beta-endorphin level which was found in the children given diclofenac and in those who served as controls. Total plasma clearance of intramuscular diclofenac sodium appears to be higher in children than in adults. A single intramuscular dose of diclofenac significantly reduces the need for an opioid analgesic in children after inguinal herniotomy or orchidopexy, and owing to its long duration of action, it offers an alternative or complementary method of pain relief to caudal analgesia.

MR imaging of the normal sacroiliac joint with correlation to histology.

OBJECTIVE: The microscopic study of the various components of joints provide a proper basis for understanding the nature of pathologic lesions to which they are subject and their imaging appearances. This study was designed to correlate MR imaging with a systematic histological study of the normal sacroiliac joint (SIJ), which to our knowledge is not available in the literature. DESIGN AND PATIENTS: Five male cadavers, aged 20 to 45 years, and seven male and seven female volunteers, aged 23 to 44 years, were investigated with oblique transaxial and coronal MR imaging of the SIJs. A variety of sequences including pre- and post-contrast T1 fat-saturated studies in the volunteers were used. Cryosectioning was performed in six SIJs of the five cadavers and compared with the MR images for the microscopic joint anatomy and assessed for the presence of abnormalities resembling those associated with sacroiliitis. RESULTS: Throughout the SIJ, the hyaline cartilage of the sacral bone and the proximal third of the hyaline iliac cartilage was strongly attached to the surrounding stabilizing ligaments, forming wide margins of fibrocartilage. In the distal one-third of the joint only, the margins of the iliac joint facet resemble that of a synovial joint, which include an inner capsule with synovial cells. The MR anatomy of the ventral and dorsal aspects of the SIJ was only adequately visualized at oblique transaxial MR imaging. No contrast enhancement occurred in the synovial tissue or in the cartilaginous joint space. The dorsal transition between the proximal 2/3 and distal 1/3 of the cartilaginous joint was at microscopy rich in anatomical and histological variants, including osseous clefts, cartilage and subchondral defects, and vascular connective tissue in the bone marrow. These were all recognized at oblique transaxial MR imaging and in coronal MR sectioning may resemble abnormalities. Otherwise, no erosions, bone marrow abnormalities, bone sclerosis or abnormal contrast enhancement occurred in the normal joints. CONCLUSIONS: The SIJ should be classified anatomically as a symphysis with some characteristics of a synovial joint being confined to the distal cartilaginous portion at the iliac side. Coronal MR imaging does not allow assessment of normal anatomy, variants or abnormalities of the ventral and dorsal margins of the cartilaginous SIJ.

Imaging of sacroiliitis in early seronegative spondylarthropathy. Assessment of abnormalities by MR in comparison with radiography and CT.

PURPOSE: To analyze the type and frequency of abnormalities of the sacroiliac joint (SIJ) in early seronegative spondylarthropathy (SpA) by MR in comparison with CT and radiography, assess the most appropriate MR sequences to be used, and introduce a new way of grading MR abnormalities of the SIJ. MATERIAL AND METHODS: The SIJs of 41 patients with early SpA (median duration of inflammatory low back pain of 19 months) were evaluated by MR imaging using STIR, T1, T2, and T1 fat saturated (FS) sequences before and after i.v. Gd contrast medium followed by staging of abnormalities. The findings were compared with those obtained by CT and radiography. RESULTS: MR and CT had equal efficacy superior to radiography in staging of erosions and osseous sclerosis. Only MR allowed visualization and grading of active inflammatory changes in the subchondral bone and surrounding ligaments in addition to bone marrow fatty accumulations. T2-weighted sequences did not contribute to assessment of sacroiliitis. CONCLUSION: MR of the SIJs is reliable in its visualization of joint erosions in early SpA and allows differentiation between active and chronic sacroiliitis. We recommend the following sequences: semicoronal T1 and both semicoronal and semiaxial STIR. If these images are normal, the examination can be finished; otherwise additional semicoronal T1 FS before and after i.v. contrast has to be performed as well as semiaxial post-contrast T1 FS.

MRI abnormalities of sacroiliac joints in early spondylarthropathy: a 1-year follow-up study.

OBJECTIVE: To describe changes in chronic and acute magnetic resonance imaging (MRI) abnormalities of the sacroiliac joints (SIJs) in early spondylarthropathy (SpA), and to associate these findings with computed tomography (CT), X-ray, and clinical findings during a 1-year follow-up. METHODS: Thirty-four patients, 20 males and 14 females, median age 27 years, with inflammatory low back pain (median 23 months) were included. MRI, CT, and X-ray, as well as clinical and laboratory tests were performed. After a follow-up period of 1 year (median 377 days) the examinations were repeated, and the findings were correlated. RESULTS: MRI and CT changes resulting from SIJ destruction increased significantly during follow-up, and the two modalities were significantly correlated. For the MRI findings of inflammatory activity, only bone marrow oedema decreased significantly. An increase in the Schober test was the only clinical examination that changed significantly. CONCLUSION: In early SpA, MRI can detect significant inflammatory and destructive changes of the SIJs over a 1-year follow-up period, in spite of minimal changes in the clinical parameters. The MRI changes in inflammatory activity are not detectable by CT and X-ray examinations. Thus, MRI may be a sensitive method, without known risks, for early diagnosis and for following disease progression in SpA.

Magnetic resonance imaging of sacroiliitis in early seronegative spondylarthropathy. Abnormalities correlated to clinical and laboratory findings.

OBJECTIVE: To compare a new MRI scoring system of the sacroiliac joints (SIJs) in early spondylarthropathy (SpA) with clinical and laboratory parameters. METHODS: Forty-one patients (24 males, 17 females) with a median age of 26 yr and a median duration of inflammatory low back pain of 19 months were included. They all fulfilled the ESSG-criteria for SpA. The patients were examined by MRI of the SIJs using a new scoring system. Clinical examinations, biochemical tests, functional score (BASFI), and pain score (BASDAI) were also performed. RESULTS: 95% of the patients had inflammation and/or destructive bone changes of the SIJs at MRI. No correlation was found between MRI pathology and clinical findings. MRI demonstrated significantly greater severity of both inflammation and destruction of the SIJs in HLA B27 positive patients than in the HLA B27 negative patients. CONCLUSIONS: In patients with early SpA, MRI was able to detect inflammatory and destructive changes of the SIJs, but the changes were not associated to clinical findings. Our results suggest a role of MRI in the detection of early-stage sacroiliitis.