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Biomedical subjects

J V Roth

Publications and source records attributed to J V Roth.

At least 19 recordsLinked to original sources
PubMed2001

Evaluation of transesophageal atrial pacing in the prone and lateral positions.

OBJECTIVE: To develop recommendations for positioning the second-generation pacing esophageal stethoscope for transesophageal atrial pacing in patients positioned prone (P), right lateral decubitus (RLD), and left lateral decubitus (LLD). DESIGN: Prospective; patients assigned consecutively. SETTING: Tertiary and university hospitals. PARTICIPANTS: Thirty (10 in each position group) adult patients undergoing surgery. INTERVENTIONS: The optimal depths of insertions (DOI) where pacing current threshold was minimal (THmin) were determined first when supine, then after positioning. MEASUREMENTS AND MAIN RESULTS: Transesophageal atrial pacing was successful in all patients supine and after positioning. The optimal DOI varied from 2 cm less deep to 4 cm deeper in positioned patients compared with supine patients. Patients positioned P required equal or up to 8 mA greater current outputs to achieve transesophageal atrial pacing; LLD and RLD patients may require up to 8 mA greater or lesser current compared with supine patients. CONCLUSION: Transesophageal atrial pacing can be used safely and effectively in patients positioned P, RLD, and LLD. Recommendations are presented for positioning the pacing esophageal stethoscope. Emphasis is given to using the lowest DOIs and smallest currents to reduce the chance of transesophageal ventricular pacing.

Adolescent↗
PubMed1997

Transdermal fentanyl system plus im ketorolac for the treatment of postoperative pain.

PURPOSE: To assess the safety and efficacy of transdermal fentanyl plus im ketorolac vs im ketorolac alone in the treatment of postoperative pain. METHODS: Ninety-two patients scheduled for surgery involving moderate to severe postoperative pain were randomized to one of two groups. Group A (n = 46) received an active fentanyl patch and group P (n = 46) received a placebo patch. Patches remained in place for 24 hr. Each patient received intraoperative ketorolac, 60 mg im. Patients were monitored for 36 hr postoperatively and the groups were analyzed for ketorolac usage, pain scores, vital signs, serum fentanyl concentrations, and adverse events. Intramuscular ketorolac was available on demand. RESULTS: Group A had lower pain scores at 8.12, 16 and 24 hr after patch placement (P < 0.05). Group A had lower heart rates, lower respiratory rates and fewer dropouts due to inadequate pain relief (4.3% vs 21.7% P < 0.05). Group A patients also used less ketorolac than group P patients (P < 0.05). The incidence of pruritus was higher in group A patients (19% vs 2%, P < 0.05), while the incidence of nausea and vomiting was not different between the two groups. Transdermal fentanyl was adequate "stand-alone" analgesia in only 23.8% of group A patients while 93.7% of the remaining group A patients receiving a combination of transdermal fentanyl and ketorolac had adequate pain relief. CONCLUSION: The transdermal fentanyl delivery system plus ketorolac im was more effective in controlling post-operative pain than ketorolac im alone. The two treatment modalities were comparable in safety with no difference in serious adverse events.

Administration, Cutaneous↗
PubMed1996

Positioning the pacing esophageal stethoscope for transesophageal atrial pacing without P-wave recording: implications for transesophageal ventricular pacing.

This study determined guidelines for positioning a new pacing esophageal stethoscope (PES) used for transesophageal atrial pacing (TEAP) without having to record esophageal P waves. In 44 patients with heights ranging from 142 cm (4'8") to 193 cm (6'4"), the PES was inserted to a depth of insertion (DOI) of 43 cm. As the PES was withdrawn, TEAP thresholds were determined at every DOI in 1-cm intervals between 43 and 25 cm DOI inclusive. TEAP was accomplished in all 44 patients. The minimum TEAP threshold (mean +/- SD 10.8 +/- 4.0 mA) was < or = 17 mA in 43 of 44 patients (98%). Except for one patient, TEAP could be accomplished over a 9- to 19-cm (mean +/- SD, 13.7 +/- 2.8 cm) wide range of DOI. Unintentional transesophageal ventricular pacing (TEVP) occurred in 15 of 44 (34%) of patients. TEVP occurred over a 1- to 7-cm (mean +/- SD, 3.7 +/- 1.7 cm) wide range of DOI; the minimum TEVP threshold averaged 30.4 +/- 6.4 mA. TEAP was consistently accomplished at DOIs more proximal than where TEVP could occur and with lower currents than that required for TEVP. An insertion depth, in centimeters, equal to half of the patient's height, in inches, produced successful TEAP in all 44 patients; the minimum TEAP threshold occurred on average at a DOI 2.6 cm more proximal. Asynchronous TEVP can be avoided by using lower currents at shallow DOIs.

Adult↗
PubMed1995

Atrioventricular sequential pacing using transesophageal atrial pacing in combination with a temporary DDD pacemaker for atrial tracking and ventricular pacing.

OBJECTIVE: To determine whether atrioventricular (A-V) sequential pacing can be accomplished using transesophageal atrial pacing (TAP) in combination with a temporary DDD pacemaker for tracking the TAP stimuli and pacing the ventricle via temporary epicardial electrodes. DESIGN: Prospective; patients enrolled consecutively. SETTING: Nonuniversity teaching hospital. PARTICIPANTS: Ten adults undergoing cardiac surgery requiring cardiopulmonary bypass. INTERVENTIONS: Two to six hours after the termination of cardiopulmonary bypass, atrial pacing was initiated via TAP. The atrial system of a temporary DDD pacemaker was connected to surface electrocardiogram (ECG) electrodes. If the temporary pacemaker could track the TAP stimuli and emit pacing stimuli resulting in ventricular capture, A-V sequential pacing was considered to have occurred. The patients were immediately restudied in the same manner with the change that the temporary DDD pacemaker sensed the TAP stimuli via temporary atrial bipolar epicardial electrodes rather than surface ECG electrodes. MEASUREMENTS AND MAIN RESULTS: Dual pacemaker A-V sequential pacing was accomplished in 17 out of 20 attempts. The atrial system of the temporary DDD pacemaker was able to sense the TAP stimulus via temporary atrial bipolar epicardial leads in 10 out of 10 patients and directly from surface ECG electrodes (right arm/left arm) in 7 out of 10 patients. CONCLUSIONS: This report demonstrates that it is possible to A-V sequentially pace using TAP in combination with a temporary DDD pacemaker for tracking the TAP stimulus and pacing the ventricle via temporary epicardial leads. This technique may be useful when A-V sequential pacing is needed and functional temporary atrial leads are not available.

Adult↗
PubMed1995

Maximum blood savings by acute normovolemic hemodilution.

Acute normovolemic hemodilution (ANH) entails collecting blood from a patient immediately prior to surgery with concurrent fluid infusion to maintain intravascular volume constant. Blood collected during ANH is later reinfused to replace the red cell losses that occur during surgery. This technique is advocated as a means to reduce or eliminate homologous blood transfusion during surgery. Published guidelines for performing ANH vary, and the literature does not describe how to perform ANH to achieve the maximum benefit for a given patient. To evaluate how to save red blood cells as much as possible via ANH, and to determine the maximum benefit that can be expected, we developed a mathematic model of the process. Using the model, the net red cell mass savings possible when using ANH can be calculated given the patient's weight, initial hematocrit and minimum safe hematocrit. Results are reported to demonstrate the impact of the initial hematocrit and minimum safe hematocrit on the red cell savings possible with ANH. The data indicate that ANH does indeed save red blood cells that would otherwise be lost during surgery. However, the red cell savings possible when using ANH are not as much as typically published and, a degree of hemodilution more than that which is typically recommended is necessary to achieve even modest red cell savings.

Blood Transfusion, Autologous↗
PubMed1995

The effect of nasal or oral gastric tubes on transesophageal atrial pacing thresholds.

This study was performed to evaluate whether the presence of either nasal or oral gastric tubes (GTs) would affect the ability to accomplish transesophageal atrial pacing (TAP). After endotracheal intubation, pacing esophageal stethoscopes were placed and the TAP thresholds were measured in 20 patients. With the PES fixed in position, GTs were inserted and pacing thresholds were remeasured. TAP was accomplished in all patients pre- and postinsertion. The mean +/- SD, range, and median TAP thresholds (mA) were 13.7 +/- 5.8, 7-25, and 12 preinsertion and 13.9 +/- 5.2, 5.5-25, and 13 postinsertion. The preinsertion-postinsertion differences ranged from -6 to 5 mA with a mean of the difference of -0.2 mA (95% confidence interval, -1.61-1.21 mA). No significant difference between the pre- and postinsertion groups was detected by the paired t-test, P = 0.77. In summary, the presence of GTs does not significantly affect TAP thresholds. Attempts to achieve TAP are expected to be successful in patients with either a nasal or oral GT in place.

Adult↗
PubMed1994

Evaluation of two commercially available carbon dioxide sampling nasal cannulae.

Our study compared two commercially available carbon dioxide sampling nasal cannulae for efficacy of oxygenation and relationship of end-tidal carbon dioxide (PETCO2) to arterial carbon dioxide (PaCO2). The two-prong nasal cannula (2PNC) has one prong dedicated to delivering O2 via one naris and the second prong dedicated to sampling exhaled gases via the other naris. The four-prong nasal cannula (4PNC) delivers O2 via a prong in each naris, and samples exhaled gases via another set of prongs in each naris. Forty six patients were divided into three groups, which received either 2 (n = 15), 3 (n = 16), or 4 (n = 15) L/min O2, respectively, and were studied sequentially with standard nasal cannula (SNC), the 2PNC, and then the 4PNC. At each O2 flow rate, PaO2 was equivalent regardless of whether the SNC, 2PNC, or 4PNC was used. Seventy-four percent (34/46) of the 2PNC and 0% (0/46) of the 4PNC PETCO2 values were within +/- 4 torr of the PaCO2 value. The authors conclude that the 2PNC and 4PNC are equally effective compared with an SNC in oxygenating patients, but the PETCO2 measured by the 2PNC provides a superior quantitative estimate of the PaCO2 than that obtained by the 4PNC.

Aged↗