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Biomedical subjects

D Hatch

Publications and source records attributed to D Hatch.

At least 19 recordsLinked to original sources
PubMed1998

A comparison of the respiratory effects of sevoflurane and halothane in infants and young children.

BACKGROUND: This study compared the respiratory effects of sevoflurane with those of halothane in anesthetized infants and young children. METHODS: Infants were randomized to receive 1 minimum alveolar concentration (MAC) halothane or sevoflurane in a mixture of nitrous oxide and oxygen. Anesthetic management included the use of a laryngeal mask. Flow, airway pressure, and the end-tidal carbon dioxide pressure (PETCO2) were measured during spontaneous ventilation and airway occlusions. Respiratory inductive plethysmography was used to assess chest wall motion. RESULTS: Measurements were obtained in 30 infants and young children (mean (SD) age, 14.5 (5.9) months), 15 of whom received sevoflurane and 15 received halothane. Some respiratory depression, as indicated by a PETCO2 of 45 mmHg (6 kPa), was present in both groups. Minute ventilation and respiratory frequency were significantly lower during sevoflurane than halothane anesthesia (4.5 compared with 5.4 (1/ m2)/min, and 37.5 compared with 46.7 breaths/min, respectively, P < 0.05). There was no difference in respiratory drive, but the shape of the flow waveform differed according to anesthetic agent, with peak inspiratory flow reached later, and peak expiratory flow reached earlier, in the sevoflurane group. There was also significantly less thoracoabdominal asynchrony during sevoflurane anesthesia. CONCLUSIONS: Minute ventilation and respiratory frequency were lower in infants during 1 MAC sevoflurane in nitrous oxide than during halothane anesthesia. However, these differences may not be clinically relevant at these concentrations, given the modest increase in PETCO2. Differences in parameters of breath timing and shape between sevoflurane and halothane suggest different effects of these anesthetic agents on ventilatory control.

Anesthetics, Inhalation↗
PubMed1998

Validation of respiratory inductive plethysmography using the Qualitative Diagnostic Calibration method in anaesthetized infants.

The aim of this study was to compare tidal volume (VT) derived from the Qualitative Diagnostic Calibration (QDC) method (VT,QDC) with measurements from pneumotachography (VT,PN,T) in anaesthetized infants. Measurements were made during spontaneous (SV) and intermittent positive pressure (IPPV) ventilation, sighs and airway occlusions. The VT,DIF was the difference between VT,QDC and VT,PNT (%VT). The contribution of the ribcage (rc) to VT,QDC (%rc) and the thoracoabdominal phase lag were also derived. Twenty-eight infants, mean (SD) age 14.0 (6.2) months were studied. VT,QDC represented VT,PNT most closely when > or = 20 breaths were analysed. There was close agreement during SV immediately after the calibration period (95% limits of agreement (LA; QDC - PNT) -23, 3.0%). The 95% LA increased to -9.6, 10.2% after 10 min. Accuracy diminished during IPPV (95% LA -38, 31%), and sighs. During airway occlusions, when VT,PNT was zero, the 95% LA were -63, 4.1 mL x kg(-1). Mean phase lag was 36 and 2%, respectively, during SV and IPPV (p<0.05). The %rc appeared to be overestimated, being in excess of 50% in infants under 12 months. The Qualitative Diagnostic Calibration method used to estimate tidal volume in anaesthetized infants was limited by the need to analyse > or = 20 breaths and by a loss of within-subject accuracy if measurement conditions or pattern of breathing changed.

Anesthesia, General↗
PubMed1997

Partial nephrectomy for pediatric renal cell carcinoma: an unusual case presentation.

Nine years after successful treatment of Stage IV neuroblastoma, a 10-year-old white girl was demonstrated to have a complex cystic mass in the upper pole of her solitary right kidney. Partial nephrectomy was performed, disclosing a renal cell carcinoma, predominantly clear cell type. No metastases were detected. Renal cell carcinoma is a rare cause of secondary malignancy. Partial nephrectomy can be used successfully to treat renal cell carcinoma in children.

Carcinoma, Renal Cell↗
PubMed1996

Renal computed tomography with 3-dimensional angiography and simultaneous measurement of plasma contrast clearance reduce the invasiveness and cost of evaluating living renal donor candidates.

Renal computed tomography (CT), 3-dimensional CT angiography (3D-CTA), and simultaneous measurement of glomerular filtration rate (GFR) by x-ray fluorescence determination of plasma contrast clearance (PCC) are alternatives to intravenous urography (IVU), renal arteriography (RA), and 24-hr urine creatinine clearance (CrCl) for evaluation of renal structure and function in living renal donor (LRD) candidates. To determine if CT, 3D-CTA, and PCC provide data comparable to IVU, RA, and CrCl, both methods were used to evaluate 23 LRD candidates. Costs were also compared. Conventional RA identified 19 accessory arteries and one case of medial fibroplasia. Each of these anomalous vessels was recognized on 3D-CTA. Venous anatomy was more clearly delineated on 3D-CTA than the venous phase of conventional RA. CT demonstrated 3 benign cysts and a single, small intraparenchymal calcification in 3 renal units. GFRs measured by PCC and CrCl were 91 +/- 4 and 132 +/- 7 ml/min/1.73m2, respectively (r = 0.64, P < 0.05). Total cost for CT/3D-CTA/PCC was 46% less than that of IVU/RA/CrCl and 40% less than RA/CrCl. CT/3D-CTA/PCC provided reliable structural and functional data at substantially less cost, discomfort, and inconvenience to the living renal donor candidate. As such, CT/3D-CTA/PCC is superior to conventional methods for evaluation of the living renal donor candidate.

Adult↗
PubMed1994

Renal cell carcinoma developing in the pediatric recipient of an adult cadaveric donor kidney.

Renal cell carcinoma is an uncommon renal tumor in children, comprising between 1.8% and 6.3% of all malignant renal tumors of childhood (whereas renal cell carcinoma is the commonest renal tumor in adults). We describe a 15-year-old girl with chronic renal failure secondary to renal dysplasia and branchio-oto-renal syndrome, who received a cadaveric renal transplant at 8 years of age from a 25-year-old male donor. She developed severe chronic rejection 4 years after the transplant. A transplant nephrectomy was performed because of persistent gross hematuria. Histopathology of this graft showed chronic severe rejection and papillary necrosis. A fortuitous finding was a 1.5-cm renal cell carcinoma at one of the poles. We suggest that tumors which occur more commonly in adults and less commonly in children must be considered in children receiving adult organ transplants.

Adolescent↗
PubMed1986

Constant flow ventilation in anesthetized patients: efficacy and safety.

Constant flow ventilation (CFV) maintains normal gas exchange in apneic dogs and has potential clinical application during thoracic surgery or pulmonary edema. We compared CFV and intermittent positive pressure ventilation (IPPV) in five healthy, anesthetized, (fentanyl, diazepam, and nitrous oxide) and paralyzed patients undergoing nonthoracic operations. Constant flow ventilation was delivered at a total flow of 0.9-1.6 L . kg-1 . min-1 (nitrous oxide-oxygen at 1:1) into two tubes of 2.5-3.5 mm inner diameter attached to each side of an 8-9 mm inner diameter orotracheal tube (OTT). Under bronchoscopic guidance, the CFV-OTT was advanced to position each ventilating tube at a mainstem bronchial orifice. Gas exhausted through the OTT lumen. If intrathoracic pressure exceeded a preset limit, a solenoid valve automatically interrupted gas flow to the patient to prevent barotrauma. Compared to IPPV, during CFV for up to 30 min average PaCO2 increased to 69.2 +/- 14.5 from 35.9 +/- 2.9 mm Hg, reflecting a calculated alveolar ventilation (VA) of 46 +/- 22% of the eucapnic level. We suggest that a technique combining CFV at lower flow rates with IPPV may prove clinically useful by allowing decreased tidal volume and inspiratory pressure while maintaining normal VA.

Adult↗
PubMedDate not supplied

Improved accuracy of the occlusion technique for assessing total respiratory compliance in infants.

The occlusion technique to measure total respiratory system compliance (Cocc) was used in 28 sedated infants with a variety of cardiopulmonary diseases and 14 anaesthetised infants during the first 2 years of life. In this report, we describe some of the potential problems in the technique and how to avoid them. Invalidation of the occlusion technique because of consistent failure to relax during brief airway occlusions occurred in only four of 42 infants despite the fact that only four infants were studied during the first month of life and 17 were between 12 and 26 months old. The technique was invalidated in two intubated infants because of persistent leaks around the endotracheal tube. In the remaining 36 infants, data sometimes had to be excluded as a result of instability and end-expiratory volume, intermittent leaks, or failure to relax during occlusions performed at low lung volumes or during inspiration. However, by performing 15-25 occlusions per infant, it was possible to obtain sufficient reliable data for accurate analysis of Cocc in all these infants. Providing that the potential errors and limitations of the occlusion technique are recognized, it appears to be applicable to a wide range of healthy and sick infants.

Forced Expiratory Flow Rates↗
PubMedDate not supplied

Treatment of bacterial meningitis with ceftazidime.

Ceftazidime was prospectively evaluated in the treatment of bacterial meningitis in 19 pediatric patients. Haemophilus influenzae type b (HIB) was the etiologic agent in 17 patients, and Streptococcus pneumonia and Neisseria meningitidis were the etiologic agents in one patient each. Ceftazidime was administered intravenously in a dosage of 150 mg/kg/day divided into eight hourly doses for a mean of 15 days (range, 14 to 22 days) for H. influenzae type b meningitis. The clinical and microbiologic response was appropriate in all cases. The mean ceftazidime CSF concentration was 6.7 micrograms/ml at approximately 2 hours following iv infusions. This concentration was 16- to greater than 100-fold the minimal bactericidal concentration determined for the isolated pathogens. These preliminary observations support ceftazidime as a candidate cephalosporin for the treatment of bacterial meningitis caused by H. influenzae. Additional study is required to further define its role in meningitis caused by S. pneumoniae and N. meningitidis.

Adolescent↗
PubMedDate not supplied

Evaluating postoperative cataract patients using the Kowa Flare Cell Meter.

The estimation of flare and cell in the anterior chamber is an important part of the postoperative care of patients who have had cataract surgery. The Kowa Flare Cell Meter uses a laser beam for a probe of light, lines it up precisely in a specially modified slit lamp, and controls and measures the results with a computer. The Kowa Flow Cell Meter incorporates a computer for input of demographics and a screen display and printer for output of the results. The anterior chamber findings are displayed both numerically and graphically.

Cataract↗