The effect of positive end-expiratory pressure on the rapid shallow breathing index.
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Humans↗
Biomedical subjects
Mohamad F El-Khatib
Publications and source records attributed to Mohamad F El-Khatib.
A new oxygenation index for reflecting intrapulmonary shunting in patients undergoing open-heart surgery.
STUDY OBJECTIVES: To assess the reliability of new and traditional oxygenation measurements in reflecting intrapulmonary shunt. DESIGN: Prospective study. SETTING: Cardiac surgery unit at a university hospital. PATIENTS: Fifty-five patients undergoing coronary artery bypass grafting. MEASUREMENTS AND RESULTS: Simultaneous blood samples were collected from an indwelling arterial line and a catheter for determination of blood gases. Standard accepted formulas were utilized to measure a new oxygenation index: PaO(2)/fraction of inspired oxygen (FIO(2)) x mean airway pressure (Paw). The standard formulas used were the oxygenation ratio (PaO(2)/FIO(2)), PaO(2)/alveolar partial oxygen pressure (PAO(2)), alveolar-arterial oxygen tension gradient (P[A-a]O(2)), and intrapulmonary shunt (venous admixture [Qsp/Qt]). There were significant negative (p < 0.05) correlations between the PaO(2)/(FIO(2) x Paw) and Qsp/Qt (r = - 0.85), between the PaO(2)/FIO(2) and Qsp/Qt (r = - 0.74), and between the PaO(2)/PAO(2) and Qsp/Qt (r = - 0.71). There was a significant positive (p < 0.05) correlation between the P(A-a)O(2) gradient and Qsp/Qt (r = 0.66). However, the correlation was strongest between the PaO(2)/(FIO(2) x Paw) and Qsp/Qt. CONCLUSION: In this group of patients, PaO(2)/(FIO(2) x Paw) might be more reliable than other oxygenation measurements in reflecting intrapulmonary shunt.
Adaptation, Physiological↗
A combination of alfentanil-lidocaine-propofol provides better intubating conditions than fentanyl-lidocaine-propofol in the absence of muscle relaxants.
PURPOSE: To compare the ease of tracheal intubation without the use of muscle relaxants following an alfentanil-lidocaine-propofol sequence vs a fentanyl-lidocaine-propofol sequence. CLINICAL FEATURES: In 80 ASA I and II adult patients undergoing elective laparoscopic surgery, we compared the intubating conditions following alfentanil 20 microg x kg(-1), lidocaine 1.5 mg x kg(-1), propofol 3 mg x kg(-1) (Group I; n = 40) vs fentanyl 2 microg x kg(-1), lidocaine 1.5 mg x kg(-1), propofol 3 mg x kg(-1) (Group II; n = 40). The intubating conditions were scored by jaw relaxation, vocal cord position and response to intubation, as well as by blood pressure and heart rate changes. The intubating conditions were good or excellent in 95% of patients in Group I vs 62.5% of patients in Group II (P < 0.05). Blood pressure decreased from a preinduction value of 86 +/- 13 mmHg to 72 +/- 28 mmHg and 74 +/- 19 mmHg in Group I, and from 85 +/- 12 mmHg to 78 +/- 15 mmHg and 78 +/- 12 mmHg in Group II, one and five minutes following intubation (P < 0.05). This drop in blood pressure was not different between the two groups. CONCLUSION: An alfentanil-lidocaine-propofol sequence offers significantly better intubating conditions than a fentanyl-lidocaine-propofol sequence in healthy adult patients.
Adult↗
Oxygenation using tidal volume breathing after maximal exhalation.
UNLABELLED: We compared, in volunteers, the oxygenation achieved by tidal volume breathing (TVB) over a 3-min period after maximal exhalation with that achieved by TVB alone. Twenty-three healthy volunteers underwent the two breathing techniques in a randomized order. A circle absorber system with an oxygen flow of 10 L/min was used. The end-expiratory oxygen concentration (EEO(2)) was monitored at 15-s intervals up to 3 min. TVB after maximal exhalation produced EEO(2) values of 68% +/- 5%, 75% +/- 5%, and 79% +/- 4% at 30, 45, and 60 s, respectively, which were significantly larger (P < 0.05) than the corresponding values obtained with TVB alone (58% +/- 5%, 66% +/- 6%, and 71% +/- 5%, respectively). In both techniques, the EEO(2) increased exponentially, with time constants of 35 s during TVB after maximal exhalation versus 58 s during TVB without prior maximal exhalation. In conclusion, maximal exhalation before TVB can hasten preoxygenation by decreasing the nitrogen content of the functional residual capacity, with a consequent increase of EEO(2) to approximately 70% in 30 s and 80% in 60 s. IMPLICATIONS: Oxygenation by using maximal exhalation before tidal volume breathing produced a significantly faster increase in end-expiratory oxygen concentration than oxygenation with tidal volume breathing alone.
Adult↗
Buspirone treatment for apneustic breathing in brain stem infarct.
We report a case of brainstem infarction resulting in apneustic breathing, which was alleviated with buspirone. We discuss apneusis, review the literature, and speculate about the benefit of serotonin 1A receptor agonists in the treatment of apneusis and other respiratory disorders.
Apnea↗
Effect of continuous positive airway pressure on the rapid shallow breathing index in patients following cardiac surgery.
OBJECTIVES: To compare the rapid shallow breathing index (RSBI) under different ventilatory support settings prior to extubation trials. DESIGN: Prospective study. SETTING: Cardiac surgery unit at a university hospital. PATIENTS: A total of 33 coronary artery bypass grafting patients ready for extubation. INTERVENTIONS: Enrolled patients received a continuous positive airway pressure (CPAP) trial of 5 cm H(2)O and fraction of inspired oxygen (FIO(2)) of 40% (condition 1), a CPAP trial of 5 cmH(2)O and FIO(2) of 21% (condition 2), and a 1-min spontaneously breathing room air trial without ventilatory support (condition 3). These trials were applied in random order. MEASUREMENTS AND MAIN RESULTS: Average values of respiratory frequency and tidal volume were measured under the three experimental conditions in all patients immediately prior to extubation. The RSBIs were determined for each patient under each condition; the average RSBIs under conditions 1, 2, and 3 were compared for significance. The average RSBIs (+/- SD) were significantly smaller under condition 1 (34 +/- 13) and condition 2 (36 +/- 14) compared to condition 3 (71 +/- 24). There was no significant difference in RSBI between conditions 1 and 2. CONCLUSIONS: The administration of 5 cm H(2)O of CPAP can influence the determination of the RSBI. In contrast, changes in FIO(2) have no effect on RSBI determination. We speculate that using the RSBI during CPAP may mislead the clinician into premature discontinuation of mechanical ventilation. Consequently, different threshold values for the RSBI should be derived for different ventilatory support levels.
Coronary Artery Bypass↗