Functional classification of patients with idiopathic scoliosis assessed by the Quantec system: a discriminant functional analysis to determine patient curve magnitude

STUDY DESIGN: A stepwise discriminant analysis was used to define a spinal deformity score based on three-dimensional measurements by the Quantec spinal image system (raster stereophotograph). OBJECTIVE: To provide functional classification of spinal deformity in patients with mild idiopathic scoliosis without using radiographs. SUMMARY OF BACKGROUND DATA: Most studies classify the degree of spinal deformity in terms of coronal plane radiograph without analyzing transverse rotation. To the authors' knowledge, no studies investigating classification of spinal deformity in idiopathic scoliosis using Quantec system measurements have been documented. METHODS: In this study, 129 patients with a single curve and 119 patients with a double curve were divided into three groups according to Cobb angle: Group 1 (less than 10 degrees ), Group 2 (10-20 degrees ), and Group 3 (greater than 20 degrees ). RESULTS: The patients were assigned to the group with the highest scores after application of a stepwise discriminant analysis. The accuracy of the classification system by functional scores for the patients with a single curve was 85% for Group 1, 63.5% for Group 2, and 71.7% for Group 3. The accuracy of classification by functional scores for the patients with a double curve was 87.1% for Group 2 and 76.1% for Group 3. CONCLUSION: The back surface image study is a method for providing a quantitative assessment of mild spinal deformity, allowing evaluation of patients by integrated three-dimensional parameters with no reference to radiographs.     

Using temporomandibular joint mobility to predict difficult tracheal intubation

The aim of this prospective study was to determine the reliability of temporomandibular joint (TMJ) mobility measurements for predicting difficult intubation. To evaluate the accuracy in predicting difficult intubation by TMJ mobility measurement, 762 patients requiring general anesthesia with tracheal intubation for elective surgery were enrolled in this prospective, observational, single-blind study. Maximum mouth opening, right–left jaw excursion, and degrees of protraction were determined with a digital inclinometer. Incisor gap was measured using a vernier caliper during full mouth opening. After induction of anesthesia using a standard protocol, the patient’s grade of laryngeal view by Cormack–Lehane classification was documented by an anesthesiologist. We found that the degrees of protraction and incisor gap in the easy intubation group were significantly higher than those in the difficult intubation group. The incisor gap was found to be more sensitive (88.37%) and more specific (95.71%) than protraction degrees (58.14% and 59.76%, respectively). The results revealed that measurements of the incisor gap and degrees of protraction may be useful routine screening tests for preoperative prediction of difficult intubation.     

Sonographic classification of idiopathic clubfoot according to severity

Our purpose was to develop a sonographic technique for clubfoot examination using measured angles to establish a classification system according to severity. Ultrasonography of 24 newborns with 32 clubfeet and 13 newborns with 22 normal feet was performed and measurements obtained. Analysis of components of variance was conducted. Patients with clubfeet showed higher dispersion in 95% confidence intervals for all angles than did patients with normal feet. A sonographic classification system was established: IIa, slight clubfoot; IIb, moderate clubfoot; IIc, severe clubfoot; IId, very severe clubfoot. Sonographic findings can be used to objectively assess various degrees of clubfoot severity.     

Acetabular dysplasia after treatment for developmental dysplasia of the hip. Implications for secondary procedures

Untreated acetabular dysplasia following treatment for developmental dysplasia of the hip (DDH) leads to early degenerative joint disease. Clinicians must accurately and reliably recognise dysplasia in order to intervene appropriately with secondary acetabular or femoral procedures. This study sought early predictors of residual dysplasia in order to establish empirically-based indications for treatment. DDH treated by closed or open reduction alone was reviewed. Residual hip dysplasia was defined according to the Severin classification at skeletal maturity. Future hip replacement in a subset of these patients was compared with the Severin classification. Serial measurements of acetabular development and subluxation of the femoral head were collected, as were the age at reduction, type of reduction, and Tonnis grade prior to reduction. These variables were used to predict the Severin classification. The mean age at reduction in 72 hips was 16 months (1 to 46). On the final radiograph, 47 hips (65%) were classified as Severin I/II, and 25 as Severin III/IV (35%). At 40 years after reduction, five of 43 hips (21%) had had a total hip replacement (THR). The Severin grade was predictive for THR. Early measurements of the acetabular index (AI) were predictive for Severin grade. For example, an AI of 35 degrees or more at two years after reduction was associated with an 80% probability of becoming a Severin grade III/IV hip. This study links early acetabular remodelling, residual dysplasia at skeletal maturity and the long-term risk of THR. It presents evidence describing the diagnostic value of early predictors of residual dysplasia, and therefore, of the long-term risk of degenerative change.     

Inter- and intraobserver variability of radiographic measurements of knee alignment.

To evaluate the variability of radiographic measurement of knee alignment by different observers, as well as repeated measurements by the same observer, standing anteroposterior radiographs of both knees of 36 patients presenting with knee pain were analyzed. Four physicians independently measured the anatomic tibiofemoral angle of both knees for a total of 72 measurements for each observer. These measurements were then repeated 1 month later in a random and blinded fashion. The same handheld goniometer was used for all measurements. The second measurement was within 3.1 degrees of the first measurement 95% of the time, and within 4 degrees 98% of the time. The maximum difference was 6 degrees. Among all four observers, measurements were within 3.7 degrees of each other 95% of the time with a maximum difference of 6 degrees. In addition to radiographic measurement, one physician also performed clinical measurement of knee alignment on these 36 patients using the same handheld goniometer. The clinical measurement was within 5 degrees of the same clinician's radiographic measurement 95% of the time with a maximum difference of 7 degrees. This variability in measuring radiographic alignment should be considered when making decisions on the need for surgical intervention or when evaluating results of procedures that relate to coronal plane alignment of the knee.     

Effects of body temperature on accuracy of continuous cardiac output measurements.

Intermittent measurement of cardiac output is routine in the critically ill surgical patient. A new catheter allows real-time continuous measurement of cardiac output. This study evaluated the impact of body temperature variation on the accuracy of these measurements compared to standard intermittent bolus thermodilution technique. This prospective study in a university hospital surgical intensive care unit included 20 consecutive trauma patients. Data were collected with pulmonary artery catheters, which allowed both continuous (COC) and bolus (COB) thermodilution measurements. The catheter was placed through either the subclavian or internal jugular vein. Measurements for COB were performed using a bolus (10 cm3) of ice-cold saline with a closed-injectate delivery system at end-expiration. Computer-generated curves were created on a bedside monitor, and the average of three measurements within 10% of one another was used as COB. COC was determined as the average of the displayed CO before and after thermodilution CO measurements. Body temperature was measured from the pulmonary artery catheter and was grouped as < or =36.5 degrees C, 36.6-38.4 degrees C, and > or =38.5 degrees C. COB and COC were compared for agreement by plotting the mean of the differences (COB - COC) between the methods. The differences were plotted against the average of each pair and analyzed with linear regression. One hundred seventy-eight paired measurements were made over a period of 1 to 3 days. CO ranged from 3.7 to 15.5 L/min. Eighty-one percent of measurements were at a temperature of 36.5-38.4 degrees C. Approximately 7% of measurements were at a temperature below 36.5 degrees C and 11.2% were in patients with a core temperature above 38.5 degrees C. Correlation between the two techniques was 0.96, 0.91, and 0.82 for temperatures of < or =36.5 degrees C, 36.6-38.4 degrees C, and > or = 38.5 degrees C, respectively. In conclusion, the COC measurements correlate well with COB in trauma patients with a core temperature < or =38.5 degrees C. The accuracy degraded at higher temperatures, which may be related to the smaller signal-to-noise ratio at elevated body temperatures.     

Femoral anteversion in children with cerebral palsy. Assessment with two and three-dimensional computed tomography scans

BACKGROUND: Assessment of femoral anteversion in children with cerebral palsy with two or three-dimensional computed tomography scans may be limited by both positional and anatomic variables. Three-dimensional computed tomography techniques are considered to be more accurate than two-dimensional imaging when the femur is not optimally positioned in the gantry or when the neck-shaft angle is increased. METHODS: Computed tomography scanning was performed on a series of nine model femora with anteversion ranging from 20 degrees to 60 degrees and neck-shaft angles ranging from 120 degrees to 160 degrees. Each femoral model was scanned in two holding devices, the first of which held the femur in optimal alignment (normal model) and the second of which held the femur in flexion, adduction, and internal rotation (cerebral palsy model) relative to the gantry. Femoral anteversion was calculated for each model from two and three-dimensional computed tomography scans by four examiners on two separate occasions. The intraobserver and interobserver reliability, the accuracy, and the effect of increasing the neck-shaft angle on the accuracy of the measurements made on the two and three-dimensional scans of the normal and cerebral palsy models were then examined. RESULTS: The mean differences in the measurements of femoral anteversion made by the same examiner (intraobserver reliability) were <2 degrees for the two-dimensional scans of the normal and cerebral palsy models and the three-dimensional scans of the normal models, and the mean difference was <4 degrees for the three-dimensional scans of the cerebral palsy models. The mean differences among examiners (interobserver reliability) were <3 degrees for the two-dimensional scans of the normal and cerebral palsy models and the three-dimensional scans of the normal models, and the mean difference was <6 degrees for the three-dimensional scans of the cerebral palsy models. The accuracy of the assessments of femoral anteversion of the normally aligned models was comparable between the two and three-dimensional scans. However, the three-dimensional assessment was significantly more accurate than the two-dimensional assessment for measurement of anteversion of the cerebral palsy models (p = 0.003). Accuracy within 5 degrees was comparable between the two and three-dimensional scans for measurement of the normally aligned models, with 86% of the two-dimensional measurements and 78% of the three-dimensional measurements falling within 5 degrees of the actual measurements. However, the accuracy within 5 degrees was significantly compromised when the models were placed in cerebral palsy alignment. Only 3% of the two-dimensional measurements and 14% of the three-dimensional measurements fell within 5 degrees of the actual measurements, with three-dimensional assessment being significantly better than two-dimensional assessment (p = 0.006). Increasing the neck-shaft angle did not significantly compromise the accuracy of measurement of femoral anteversion with either the two-dimensional or the three-dimensional technique (p > 0.05 for all comparisons). CONCLUSIONS: When adequate alignment of the femur in the computed tomography scanner was possible, a simple two-dimensional technique exhibited excellent intraobserver and interobserver reliability and clinically acceptable accuracy within the relevant ranges of anatomic variability tested (neck-shaft angles of 120 degrees to 160 degrees and femoral anteversion of 20 degrees to 60 degrees). When optimal alignment of the femur in the scanner was not possible, neither two-dimensional nor three-dimensional techniques exhibited clinically acceptable accuracy for the measurement of femoral anteversion.     

Surgical treatment of unstable distal radius fractures with volar locking plates

BACKGROUND: Surgical treatment of unstable distal radius fractures does not always yield a satisfactory outcome. The several surgical strategies available have problems associated with them. This study was undertaken to determine if volar locking plate fixation could be useful for treating unstable distal radius fractures. METHODS: This retrospective follow-up study assessed 24 fractures in 24 patients with unstable distal radius fractures surgically treated with one of three volar locking plate systems. According to the AO classification system, 7 patients had type A3 fractures, 5 patients had type C2 fractures, and the remaining 12 patients had type C3 fractures. Radiographic measurements included volar tilt, radial inclination, and ulnar variance. Clinical outcomes were evaluated by active range of motion of the wrist and forearm, grip strength, Saito's wrist score, and the Japanese Society for Surgery of the Hand version of the Disabilities of the Arm, Shoulder, and Hand questionnaire (JSSH version of the DASH). RESULTS: At the time of final follow-up (5 months minimum) the mean volar tilt was 8.1 degrees , radial inclination was 20 degrees, and ulnar variance was 0.4 mm. Mean wrist extension measured 61 degrees, wrist flexion 55 degrees, radial deviation 23 degrees, ulnar deviation 35 degrees, pronation 87 degrees, and supination 87 degrees. Grip strength recovered to a mean of 84% of the grip strength in the contralateral limb for patients who had injured their dominant hand and to a mean of 73% for patients who had injured their nondominant hand. Saito's wrist score calculations revealed 20 excellent and 4 good results. The mean DASH disability/symptom score was 9.9 points, and the mean DASH work module score was 8.2 points. CONCLUSIONS: The present study demonstrated that unstable distal radius fractures could be successfully treated with volar locking plate systems.     

Sonographic assessment of stable hip reposition in newborns and infants with congenital hip dysplasia treated conservatively]

The paper presents a sonographic assessment of dysplastic hip morphology with clinically diagnosed instability after achieving stable reposition. The analysed group comprised 42 dysplastic unstable hips. They were classified according to the Graf classification as type D, III and IV. The analysed group was divided into 2 subgroups according to the child's age at the time treatment was began. Group I comprised children in whom treatment was began at age 2-6 weeks. Group II included children who were 7-12 weeks old at the time treatment was began. The morphology of the dysplastic hip was assessed basing on angle alpha and beta measurements. Stable repositioning of the hip was achieved on average 5 weeks after conservative treatment was started. The average alpha angle was 50 degrees in group I and 48 degrees in group II; accordingly, angle beta was on average 60 degrees and 69 degrees.     

Measurement error in assessment of vertebral rotation using the Perdriolle torsionmeter.

The Perdriolle torsionmeter assesses vertebral rotation on a spinal radiograph. It is frequently used to measure improvement in spinal derotation following Cotrel-Dubousset instrumentation for scoliosis. In this study, intraobserver and interobserver measurement error was examined during use of the torsionmeter. Intraobserver error was as follows: 53% of the measurements were accurate to within 5 degrees, and 21% erred greater than 10 degrees. Error from the actual value averaged 6 degrees. Interobserver error was as follows: Among six observers, only one third of the radiographs had measurements within 5 degrees of each other. Another one third erred by more than 10 degrees. Because of this significant intraobserver and interobserver error, precise measurements of rotation using the torsionmeter cannot be expected. Efforts to quantify spinal derotation with the torsionmeter after Cotrel-Dubousset instrumentation may not be valid.     

Computed tomography measurement of the accuracy of component version in total hip arthroplasty

The version of the acetabular and femoral components in 111 primary total hip arthroplasties was prospectively evaluated intraoperatively by the surgeon and compared with postoperative computed tomography (CT) scan measurements. Intraoperative estimations by the surgeons for acetabular and femoral components were all within 10 degrees to 30 degrees anteversion, with means of 16.0 degrees (SD = 4.0 degrees ) and 16.4 degrees (SD = 3.2 degrees ), respectively. However, CT scan acetabular measurements ranged from 12 degrees retroversion to 52 degrees anteversion (mean = 22.0 degrees anteversion, SD = 14.0 degrees ). Similarly, femoral component version ranged from -15 degrees retroversion to 45 degrees anteversion (mean = 16.8 degrees anteversion, SD = 11.1 degrees ). According to CT calculations, only 71% of femoral and 45% of acetabular components were within the expected clinical version range. In conclusion, the intraoperative estimation of acetabular and femoral version in a total hip arthroplasty is of limited accuracy.     

Proximal femoral geometry in cerebral palsy: a population-based cross-sectional study

There is much debate about the nature and extent of deformities in the proximal femur in children with cerebral palsy. Most authorities accept that increased femoral anteversion is common, but its incidence, severity and clinical significance are less clear. Coxa valga is more controversial and many authorities state that it is a radiological artefact rather than a true deformity. We measured femoral anteversion clinically and the neck-shaft angle radiologically in 292 children with cerebral palsy. This represented 78% of a large, population-based cohort of children with cerebral palsy which included all motor types, topographical distributions and functional levels as determined by the gross motor function classification system. The mean femoral neck anteversion was 36.5 degrees (11 degrees to 67.5 degrees) and the mean neck-shaft angle 147.5 degrees (130 degrees to 178 degrees). These were both increased compared with values in normally developing children. The mean femoral neck anteversion was 30.4 degrees (11 degrees to 50 degrees) at gross motor function classification system level I, 35.5 degrees (8 degrees to 65 degrees ) at level II and then plateaued at approximately 40.0 degrees (25 degrees to 67.5 degrees) at levels III, IV and V. The mean neck-shaft angle increased in a step-wise manner from 135.9 degrees (130 degrees to 145 degrees) at gross motor function classification system level I to 163.0 degrees (151 degrees to 178 degrees) at level V. The migration percentage increased in a similar pattern and was closely related to femoral deformity. Based on these findings we believe that displacement of the hip in patients with cerebral palsy can be explained mainly by the abnormal shape of the proximal femur, as a result of delayed walking, limited walking or inability to walk. This has clinical implications for the management of hip displacement in children with cerebral palsy.     

Axillary and tympanic membrane temperature measurements are unreliable early after cardiopulmonary bypass

BACKGROUND AND OBJECTIVE: Inaccurate measurements of body temperature following cardiopulmonary bypass may be associated with serious complications. The purpose of this study was to determine whether axillary and tympanic temperature measurements correlate with the urinary bladder temperature in the early postcardiac surgery period. METHODS: Forty-nine adult patients who underwent cardiac surgery under cardiopulmonary bypass at our institution were prospectively studied. Urinary bladder, right axillary, right tympanic and left tympanic temperature measurements were simultaneously recorded at 0, 6, 12 and 18 h following cardiopulmonary bypass. Patients had one to four sets of recordings and a total of 629 temperature measurements were recorded. The mean difference (bias) between the bladder and each of the other methods and limits of agreement were calculated using Bland and Altman method. RESULTS: The mean core body temperature recorded from the bladder on admission to the intensive care unit was 36.4 degrees C. After 6, 12 and 18 h the mean core body temperature was 37.4 degrees C (range: 35.2-39.0), 37.5 degrees C and 37.45 degrees C, respectively. The mean differences (bias) between the bladder temperature and the other three methods were: left tympanic, 0.65 degrees C (95% CI: -0.24 to 1.58); right tympanic, 0.57 degrees C (95% CI: -0.48 to 1.63) and right axillary, 0.55 degrees C (95% CI: -0.27 to 1.36). CONCLUSIONS: The axilla and tympanic membrane are unreliable sites for core body temperature measurement early after cardiopulmonary bypass in adult patients and clinical decisions should be based on more reliable methods.     

Assessment of variations in the measurement of hip ultrasonography by the Graf method in developmental dysplasia of the hip

The purpose of this study was to assess the variations in the measurement of hip ultrasonography using the Graf method in developmental hip dysplasia. Twenty-two observers independently analyzed 20 hip ultrasonograms on two occasions. Intraobserver and interobserver agreement ratios on the exact Graf classification were 65% and 51%, respectively. Intraobserver and interobserver agreement ratios on the treatment method according to the hip type were 76% and 64%, respectively. Average intraobserver and interobserver differences were 4.0 degrees and 5.1 degrees for the alpha angle, and 5.9 degrees and 10.1 degrees for the beta angle, respectively. It was concluded that having a basic knowledge of the Graf method was the key point, and the observer's previous number of examinations had no effect on the results.     

Longitudinal study of normal hip development by ultrasound

In the management of a newborn's hips, ultrasonography has proven to be useful. The progression of measurements at different ages in normal hips has not been thoroughly investigated. The purpose of this prospective study was to assess the longitudinal development of clinically stable hips. Forty newborns (80 hips) were assessed by ultrasonography at birth and at 6 and 12 weeks of age. Femoral head coverage (FHC), alpha angles, and beta angles were measured. The results showed a significant change in values between the three points in time for all measurements (P < 0.001). The mean FHC progressed from 58.4% to 65.6% to 69.3%, the mean alpha angle from 70.2 degrees to 76.8 degrees to 80.3 degrees , and the mean beta angle from 52.1 degrees to 45.7 degrees to 42.9 degrees . In clinically stable hips, the FHC and alpha and beta angles change significantly over time; therefore, it is important to consider the child's age when interpreting ultrasound images.     

Measurement of glenoid version: conventional radiographs versus computed tomography scans

Glenoid version seems to play an important role in the stability and loading of the glenohumeral joint. The purpose of this study was to compare measurements of glenoid version on axillary views and computed tomography (CT) scans. Radiographs and CT scans of 25 patients evaluated predominantly for glenohumeral joint instability and 25 patients after implantation of a total shoulder prosthesis were analyzed by 3 independent observers. In all patients glenoid version was determined on an axillary view and on a CT scan at the mid-glenoid level. The mean glenoid version measured on CT scans was 3 degrees of retroversion in the instability group (range, 7 degrees of anteversion to 16 degrees of retroversion) and 2 degrees of anteversion in the total shoulder prosthesis group (range, 16 degrees of anteversion to 23 degrees of retroversion). Glenoid retroversion was overestimated on plain radiographs in 86%. The mean difference between measurements of glenoid version on axillary views and CT cuts was 6.5 degrees (range, 0 degrees -21 degrees ), and the coefficient of correlation between these measurements was 0.33 in the instability group and 0.67 in the prosthesis group. In conclusion, glenoid version cannot be determined accurately on standard axillary radiographs, either preoperatively or postoperatively. Studies that assess the role of glenoid component orientation should use a reproducible method of assessment such as CT.     

A Plantarflexory-Shortening Osteotomy for Hallux Rigidus: A Retrospective Analysis

This retrospective study reported the clinical and radiographic findings of a plantar-flexor-shortening first metatarsal osteotomy for treatment of hallux rigidus. Twenty-six patients (33 feet) were evaluated with a mean 34.4 months follow-up (range, 18-65 months). Assessment consisted of clinical measurements of total range of first metatarsophalangeal joint motion and radiographic measurements of first metatarsophalangeal joint space, including plantarflexion and shortening of the first metatarsal. Patients were evaluated postoperatively using the American Orthopedic Foot and Ankle Society's Hallux Metatarsophalangeal-Interphalangeal Scoring System. The mean preoperative first metatarsophalangeal joint total range of motion was 33.5 degrees (5 degrees -60 degrees ), and postoperatively increased to 72.1 degrees (50-100 degrees ), a mean increase of 38.6 degrees at follow-up (range, 25 degrees -60 degrees ) (P < .001). This range of motion was observed despite a lack of significant improvement in radiographic joint space measurements, (preoperative mean 1.26; postoperative mean 1.82). Postoperative radiographs also demonstrated 1-4 mm of plantarflexion of the first metatarsal head, and a mean 6.1 mm shortening of the first metatarsal. At last follow-up, 85% (22/26) of patients rated their result as very good to excellent, 8% (2/26) reported a good result, 4% (1/26) a fair result, and 4% (1/26) a poor result. The mean postoperative rating scale score was 78.1/100. No patient required revisional surgery for hallux rigidus. Four patients had postoperative lesser metatarsalgia, 3 of which were self-limiting, and one that resolved following surgery. The results of this study show the plantar-flexor-shortening first metatarsal to be an effective surgical treatment for hallux rigidus with reproducible deformity correction and patient satisfaction.     

Precision of the measurements of periprosthetic bone mineral density in hips with a custom-made femoral stem

Our aim was to determine the precision of the measurements of bone mineral density (BMD) by dual-energy x-ray absorptiometry in the proximal femur before and after implantation of an uncemented implant, with particular regard to the significance of retro- and prospective studies. We examined 60 patients to determine the difference in preoperative BMD between osteoarthritic and healthy hips. The results showed a preoperative BMD of the affected hip which was lower by a mean of 4% and by a maximum of 9% compared with the opposite side. In addition, measurements were made in the operated hip before and at ten days after operation to determine the effect of the implantation of an uncemented custom-made femoral stem. The mean increase in the BMD was 8% and the maximum was 24%. Previous retrospective studies have reported a marked loss of BMD on the operated side. The precision of double measurements using a special foot jig showed a modified coefficient of variation of 0.6% for the non-operated side in 15 patients and of 0.6% for the operated femur in 20 patients. The effect of rotation on the precision of the measurements after implantation of an uncemented femoral stem was determined in ten explanted femora and for the operated side in ten patients at 10 degrees rotation and in 20 patients at 30 degrees rotation. Rotation within 30 degrees influenced the precision in studies in vivo and in vitro by a mean of 3% and in single cases in up to 60%. Precise prediction of the degree of loss of BMD is thus only possible in prospective cross-sectional measurements, since the effect of the difference in preoperative BMD, as well as the apparent increase in BMD after implantation of an uncemented stem, is not known from retrospective studies. The DEXA method is a reliable procedure for determining periprosthetic BMD when positioning and rotation are strictly controlled.     

Temperature corrections in routine spirometry.

Forced expiratory volume (FEV1) and forced vital capacity (FVC) were measured in nine normal subjects with three Vitalograph and three rolling seal spirometers at three different ambient temperatures (4 degrees C, 22 degrees C, 32 degrees C). When the results obtained with the rolling seal spirometer were converted to BTPS the agreement between measurements in the three environments improved, but when the Vitalograph measurements obtained in the hot and cold rooms were converted an error of up to 13% was introduced. The error was similar whether ambient or spirometer temperatures were used to make the conversion. In an attempt to explain the behaviour of the Vitalograph spirometers the compliance of their bellows was measured at the three temperatures. It was higher at the higher temperature (32 degrees C) and lower at the lower temperature (4 degrees C) than at the normal room temperature. These changes in instrument compliance could account for the differences in measured values between the two types of spirometer. It is concluded that the ATPS-BTPS conversion is valid and necessary for measurements made with rolling seal spirometers, but can cause substantial error if it is used for Vitalograph measurements made under conditions other than normal room temperature.     

Uneven myocardial hypothermia among cardiac chambers during hypothermic myocardial preservation

During the development of methods to protect the heart from ischaemic injury, attention has been focused on protection of the left ventricle. In an attempt to assess right heart preservation. 55 consecutive patients undergoing open heart surgery were studied. Mean aortic cross-clamp time was 59.3 +/- 29.4 min. Temperature probes were inserted into the right atrium (RA), right ventricle (RV), and left ventricle (LV). During cardioplegia, the mean myocardial temperatures of RA, RV and LV were 19.1 degrees +/- 4.1 degrees C, 12.7 degrees +/- 4.8 degrees C and 7.3 degrees +/- 3.4 degrees C, respectively. Of the LV temperature measurements, 67.2% were 10 degrees C or lower. By contrast, 94.1% of RA measurements and 58.5% of RV measurements were above 10 degrees C. The inhomogeneity of chamber temperatures was observed irrespective of the patient's disease or age and whether the atrium or right ventricle were open or not. Hearts with mitral regurgitation (MR), in contrast to mitral stenosis and stenoinsufficiency, had higher LV temperatures, similar to those in the RV. We conclude that there is uneven hypothermia among the three cardiac chambers during hypothermic cardioplegic arrest, regardless of disease states except MR and regardless of age and procedure performed.