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K Guntupalli

Publications and source records attributed to K Guntupalli.

14 recordsLinked to original sources
PubMed2005

Deposition pattern of heliox-driven bronchodilator aerosol in the airways of stable asthmatics.

To compare the deposition patterns of heliox-driven and air-driven radiolabeled bronchodilator aerosol, a prospective randomized study was undertaken at the Ben Taub Hospital in Houston, Texas. The working hypothesis was that nebulization with heliox would improve the peripheral deposition of a bronchodilator aerosol. Twelve mild-moderate known asthmatics were recruited for the study. They were asked to withhold medications for 8-24 hours prior to reporting for the study. Each subject was randomized to receive either heliox or oxygen for delivery of albuterol labeled with Tc-99m DTPA. Prior to the nebulization, baseline spirometry was performed. Following nebulization, the subjects were scanned for 1,000,000 counts on the ADAC Genesis Scanner. A postbronchodilator spirometry was then performed. Subjects returned about a week later, this time to have the same process repeated with the other gas. The normalized pixel counts were obtained, and the frequency distribution histograms were constructed for each of the deposition images. Skew and kurtosis were calculated. A lower skew and kurtosis value suggests a more peripheral distribution of the bronchodilator, whereas a higher pixel count corresponds with an increased area and uniformity of deposition. There were no statistically significant differences in baseline PFTs on the 2 days of the study. The pixel count was statistically higher after the heliox-driven nebulization than the air-driven nebulization. The skew and kurtosis values were lower after the heliox-driven nebulization than after the air-driven nebulization of radiolabeled aerosol. All patients had a good bronchodilator response with either driving gas. However, the degree of improvement was more with heliox-driven nebulization than with air-driven nebulization. We conclude that aerosol delivery with heliox results in more uniform and peripheral deposition. Thus, this mode of delivery can be used when uniform, peripheral deposition is desired as with drug delivery during an exacerbation or with aerosolized gene therapy.

Administration, Inhalation↗
PubMed1999

Pharmacokinetics of the nitric oxide synthase inhibitor L-NG-methylarginine hydrochloride in patients with septic shock. Glaxo Wellcome International Septic Shock Study Group.

OBJECTIVES: To characterize the pharmacokinetics of L-NG-methylarginine in patients with septic shock. METHODS: This was an international, uncontrolled, open-label study of L-NG-methylarginine (546C88) therapy given to 32 patients with septic shock. It was conducted in hospital-based intensive care units that admit general surgical and medical patients. Patient cohorts received an infusion of L-NG-methylarginine at fixed dose rates of 1, 2.5, 5, 10, and 20 mg/kg/h for up to 8 hours. The 5 dosing regimens were administered sequentially to separate groups of patients. RESULTS: Of the 32 patients studied, 23 received complete 8-hour infusions. In the other 9 patients, the infusion was terminated prematurely within the first 1/2 to 4 hours. Median clearance of L-NG-methylarginine averaged 485 mL/h/kg for the 1 and 2.5 mg/kg/h dosing cohorts combined but decreased to 283, 181, and 98 mL/h/kg for the 5, 10, and 20 mg/kg/h dosing cohorts, respectively. Median renal clearance was similar at 9 to 26 mL/h for the 1, 2.5, and 5 mg/kg/h dosing cohorts but increased to 156 and 284 mL/h for the 10 and 20 mg/kg/h dosing cohorts, respectively. Median steady-state volume of distribution was similar in all 5 dosing cohorts, averaging 0.66 to 0.82 L/kg. CONCLUSIONS: The 80% decrease in clearance from 485 to 98 mL/h/kg with the increase in dose suggests that a predominant metabolic pathway(s) of L-NG-methylarginine, accounting for at least 80% of clearance, is becoming progressively saturable in association with L-NG-methylarginine infusion rates > or = 5 mg/kg/h. Therefore the use of L-NG-methylarginine infusion rates > or = 5 mg/kg/h are typically expected to result in progressive inhibition of nitric oxide synthase activity. Consequently, patient hemodynamics should be monitored closely to avoid an excessive increase in vasomotor tone, which would be manifest by either an increase in mean arterial pressure or a decrease in cardiac output. The infusion rates of conventional vasopressor(s) (eg, norepinephrine [BAN, noradrenaline]) or L-NG-methylarginine or both may need to be reduced accordingly.

Adult↗
PubMed1999

An open-label dose escalation study of the nitric oxide synthase inhibitor, N(G)-methyl-L-arginine hydrochloride (546C88), in patients with septic shock. Glaxo Wellcome International Septic Shock Study Group.

OBJECTIVE: To assess the effects of the nitric oxide synthase inhibitor, 546C88, in patients with septic shock and to evaluate the range of dose rates that sustain mean arterial pressure (MAP) of > or =70 mmHg. DESIGN: Multicenter, open-label, uncontrolled, dose range finding study. SETTING: Ten intensive care units in Europe and the United States. PATIENTS: Thirty-two patients with septic shock diagnosed within <24 hrs. INTERVENTIONS: Patients received a fixed dose rate of 546C88 at either 1(n = 6), 2.5 (n = 6), 5 (n = 4), 10 (n = 5), or 20 mg/kg/hr (n = 11) by intravenous infusion for up to 8 hrs. Conventional vasoactive therapy was restricted to norepinephrine and/or dobutamine. During 546C88 therapy, MAP was to be maintained between 70 and 90 mm Hg, while attempting to withdraw any concurrent norepinephrine. MEASUREMENTS AND MAIN RESULTS: Systemic and pulmonary hemodynamics, blood gases, and plasma nitrate were assessed. Infusion of 546C88 (1-20 mg/kg/hr) for up to 8 hrs enabled a 60 to 80% reduction of the norepinephrine dose rate in all cohorts, while MAP was sustained at >70 mm Hg. There was an increase in vascular tone and a decrease in cardiac index within the 1st hr of therapy. Systemic vascular resistance returned toward baseline with reduction of concomitant administration of norepinephrine. The decline in oxygen delivery was associated with an increase in extraction and, therefore, the maintenance of oxygen consumption. There was a sustained reduction of venous admixture within the 1st hr of therapy. 546C88 was not associated with any major or dose-dependent adverse effect on pulmonary, hepatic, or renal function. CONCLUSIONS: Treatment with the nitric oxide synthase inhibitor, 546C88, can restore the balance of vasomotor tone, thereby, maintaining blood pressure and reducing or eliminating the requirement for norepinephrine therapy in patients with septic shock. Infusion of 546C88 (1-20 mg/kg/hr) appears to have a satisfactory overall safety profile.

Adult↗
PubMed1995

Bronchiectasis and homozygous (P1ZZ) alpha 1-antitrypsin deficiency in a young man.

Pulmonary complications of alpha 1-antitrypsin deficiency are most commonly manifested by panlobular emphysema. This report describes histologically proven bronchiectasis in a 21 year old man with massive haemoptysis and homozygous deficiency of alpha 1-antitrypsin. Neither panlobular emphysema nor cirrhosis of the liver were present. Bronchiectasis must be considered part of the spectrum of the pulmonary pathology that may be encountered in individuals with alpha 1-antitrypsin deficiency.

Adult↗
PubMed1990

Pulmonary embolism in end stage renal disease.

Clinically significant pulmonary embolism is considered to be rare in patients with end stage renal disease. Two cases with long standing renal disease on dialysis, are reported where pulmonary embolism contributed significantly to morbidity and mortality. One patient had hypotension during dialysis. The differential diagnosis of sustained hypotension during dialysis or in the ICU should include pulmonary embolism. Establishing the diagnosis may require pulmonary angiography.

Diagnosis, Differential↗
PubMed1988

Driving pressure and arterial carbon dioxide tension during high-frequency jet ventilation in postoperative patients.

To achieve normocarbia during conventional mechanical ventilation, ventilator settings are determined initially on the basis of body weight. The best ventilator settings for CO2 elimination during high-frequency jet ventilation (HFJV) have not been so clearly defined. A recent study has suggested that eucarbia will be obtained with HFJV when tidal volume (VT) per kg of body weight is kept within a narrow, well-defined range. In the same study, a "bench test" demonstrated that VT was directly proportional to the jet ventilator driving pressure (DP). The goal of our study was to confirm this recommended VT/kg to obtain eucarbia and to determine whether the relation observed between VT and DP in the laboratory was true clinically. We studied 14 patients admitted to the ICU for postoperative support. We determined a good correlation between DP and VT/kg (r = .811, p less than .001) for the group as a whole and a good inverse correlation between DP or VT/kg and PaCO2 for most individual patients; however, there was a poor inverse correlation between DP or VT/kg and PaCO2 for the group as a whole, due to wide patient-to-patient variation in the efficiency of jet ventilation. We conclude that there is no universal formula for setting jet ventilator DP or VT/kg to affect normocarbia in humans.

Body Weight↗
PubMed1987

Synchronous versus nonsynchronous high-frequency jet ventilation: effects on cardiorespiratory variables and airway pressures in postoperative patients.

In order to compare the differences of high-frequency jet ventilation (HFJV) synchronized with the cardiac cycle (sync) to that nonsynchronized with the cardiac cycle (async), ten stable postoperative ICU patients, without heart failure, in sinus rhythm were ventilated randomly in either mode. The async mode was HFJV at 100 cycle/min, while the sync mode was HFJV triggered by the R-wave of the ECG tracing. The heart rate ranged between 64 and 127 beat/min. Synchronization was studied at one of two periods, sync 0 and sync 60. Sync 0 consisted of inspiration triggered by the R-wave, with jet ventilation occurring early in systole; sync 60 represented a 60% delay of the time between the succeeding R-waves, with jet ventilation occurring in mid-diastole. There was no significant difference in the cardiorespiratory data when async was compared to either sync 0 or sync 60. Therefore, in these patients without heart failure, the selection of async vs. either sync mode appeared to have neither adverse nor beneficial hemodynamic effects.

Evaluation Studies as Topic↗
PubMed1984

High-frequency jet ventilation in the postoperative period: a review of 100 patients.

One hundred patients were ventilated with high-frequency jet ventilation (HFJV) during the initial 24-h postoperative period in the surgical and neurosurgical ICUs. Eighty-three were successfully weaned, 2 could not be ventilated adequately with HFJV, and 15 with criteria of acute respiratory failure received HFJV for up to 21 days. A HFJV delivery system consisted of jetting and entrainment systems, both with their own humidification designs. An initial mode of HFJV using 35 psi, jet rate 100 cycle/min and inspiratory time 30% provided a mean PaCO2 of 34 torr in 38 patients studied. A comparison of HFJV without and with a positive end-expiratory pressure (PEEP) of 10 cm H2O indicated a decrease in mean Qsp/Qt from 17% to 13% with decrease in cardiac index (CI) from 3.39 to 2.81 L/min X m2; this effect is similar to PEEP applied to a conventional ventilator. Weaning proved to be simple and comfortable for the patient. In the light of our experience, we believe that HFJV is both feasible and practical for the postoperative patient and should be introduced into routine clinical use.

Adolescent↗
PubMed1984

High-frequency jet ventilation versus intermittent positive-pressure ventilation.

Airway pressures and cardiorespiratory variables were compared for conventional ventilation (CV) and high-frequency jet ventilation (HFJV), at a similar fraction of inspired O2 (FIO2), positive end-expiratory pressure (PEEP) and PaCO2 in 11 ICU patients. For CV and HFJV, respectively, peak (PAP) and mean airway pressures (Paw) were 15.4 and 9.1 mm Hg and 4.4 and 5 mm Hg. Cardiac index (CI) was 2.54 and 2.60 L/min X m2, total systemic vascular resistance index (SVRI) 2846 and 2923 dyne X sec/cm5 X m2, PaO2 207 and 149 torr, and Qsp/Qt 7% and 11%. HFJV decreased significantly PAP and was less likely to produce pulmonary barotrauma. Cardiac indices were not different, indicating that this variable may be affected by Paw. HFJV neither increased nor decreased CI at similar PEEP and PaCO2 as compared to CV. The decrease in PaO2 and increase in Qsp/Qt may be due to small inspired gas volumes potentiating microatelectasis. On the basis of this study, we recommend initiating HFJV at FIO2 of 0.9 and PEEP of 5 cm H2O, and monitoring both PAP and Paw.

Aged↗
PubMed1984

High-frequency jet ventilation and tracheobronchial suctioning.

Oxygenation and ventilation were assessed in 15 postoperative patients before, immediately after, and 3 min after 15 sec of tracheobronchial suctioning in the presence or in the absence of high-frequency jet ventilation (HFJV). When HFJV was continued during suctioning, the mean PaO2 decrease was only 15 +/- 9 torr, compared to a 90 +/- 16 torr decrease when HFJV was discontinued. This difference demonstrates that continuation of HFJV during tracheobronchial suctioning prevents a decrease in PaO2.

Bronchi↗
PubMed1983

Renal function and renin secretion during high frequency jet ventilation at varying levels of airway pressure.

The effect of positive end-expiratory pressure (PEEP) on plasma renin activity (PRA), renal function, and cardiovascular (CV) hemodynamics during high frequency jet ventilation (HFJV) was observed in 7 patients. The addition of PEEP during HFJV increased PRA while decreasing stroke index (SI) and cardiac index (CI). These changes were associated with decreased urinary flow, creatinine clearance, and fractional excretion of sodium. In contrast, HFJV at zero end-expiratory pressure (ZEEP) maintained normal PRA, renal function, and CV hemodynamics. The authors conclude that the alteration of renal function during HFJV is a function of airway pressure rather than the effects of the ventilatory frequency. The deterioration of renal function may have been due to changes in PRA or CV dynamics.

Adult↗