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At least 199 records · Page 11Linked to original sources
PubMed2006

Effects of positive end-expiratory pressure on systemic haemodynamics, with special interest to central venous and common iliac venous pressure in liver transplanted patients.

BACKGROUND AND OBJECTIVES: Positive end-expiratory pressure may alter cardiac function and systemic haemodynamics. As transplanted livers may be sensitive to liver congestion, the aim of our study was to evaluate the effect of positive end-expiratory pressure on the cardiovascular system and in particular on central venous and iliac venous pressure in liver transplanted patients. PATIENTS AND METHODS: Seventy-two liver transplant patients were enrolled in this prospective, interventional study. On admission to our Intensive Care Unit all patients were ventilated in a biphasic positive airway pressure mode. Haemodynamic effects of three randomly set levels of end-expiratory pressures (0, 5 and 10 mbar) were studied in the immediate postoperative period in all patients. Mean arterial pressure, central venous pressure, pulmonary capillary wedge pressure, central iliac venous pressure and cardiac index were recorded and analysed at each of the three end-expiratory pressure levels. RESULTS: The values of central- and wedge-pressure significantly increased with increased end-expiratory pressure. Central venous pressure increased by 24% and wedge pressure showed a 6% increase at 10 mbar in comparison to 0 mbar. The values for cardiac index and mean arterial pressure showed no statistically significant difference at 10 mbar as compared to 0 and 5 mbar. The mean pulmonary arterial and common iliac venous pressure were unaffected by different positive end-expiratory pressure levels. CONCLUSIONS: Short-term pressure controlled ventilation with end-expiratory pressure up to 10 mbar does not significantly impair systemic haemodynamics in liver-transplanted patients. Further studies are needed to determine whether these findings could be confirmed with higher pressure levels and/or over a longer period of ventilation time.

Aged↗
PubMed1986

Assessment of pericardial constraint: the relation between right ventricular filling pressure and pericardial pressure measured after pericardiocentesis.

Experimental studies have shown that right ventricular filling pressure (that is, intracavitary diastolic pressure) approximates pericardial surface pressure but, in many patients after removal of pericardial effusion, right ventricular filling pressure has been found to markedly exceed pericardial pressure recorded by an open catheter. The aim of this study was to determine whether this apparent contradiction was related to the technique of pericardial pressure measurement. Nine patients with chronic pericardial effusion were studied and, although these pressures diverged to varying degrees in individual patients, the previous observation was confirmed in that, although initially similar, right ventricular filling pressure and pericardial pressure (measured by means of an open catheter) tended to diverge during removal of the effusate; when the evacuation was as complete as possible pericardial pressure was 2.1 +/- 1.0 (mean +/- SE), while right ventricular filling pressure was 8.7 +/- 1.7 mm Hg (p less than 0.01). In six open chest, anesthetized, volume-loaded dogs with pericardial effusion (50 ml), right ventricular filling pressure and pericardial pressures measured with both open catheter and flat balloon were all equal. With decreasing volume of pericardial fluid, right ventricular filling pressure and pericardial pressure (by catheter) diverged as had been observed in patients. However, pericardial pressure (balloon) continued to be equal to right ventricular filling pressure. (With 0 ml in the pericardium, right ventricular filling pressure = 12.9 +/- 0.9 mm Hg, pericardial pressure [catheter] = 1.4 +/- 1.9 mm Hg and pericardial pressure [balloon] = 12.4 +/- 1.5 mm Hg.) Thus, these observations support the use of right ventricular filling pressure as an estimate of pericardial constraint in patients.

Adult↗
PubMed1974

Fluid replacement monitoring: effect of dextran overload, norepinephrine drip, and positive pressure ventilation on systemic arterial, right atrial pulmonary wedge, and left atrial pressures in dogs.

The effects of dextran overload, norepinephrine drip and positive pressure ventilation upon right atrial, pulmonary wedge, left atrial and systemic arterial pressures were studied in 15 dogs. Rapid intravenous infusion of Dextran 70 invariably produced a marked and statistically significant (p < .001) rise in right atrial, pulmonary wedge and left atrial pressures. The rise in left atrial pressure invariably exceeded the rise in right atrial pressure, and the difference in maximum pressures averaged 10.8 mm Hg (p < .001). Thus acute fluid overload and pulmonary edema can be produced by rapid infusion of colloid solution in the absence of a marked rise in right atrial pressure, a point of considerable clinical importance. The rapid infusion of dextran produced a rise in systemic arterial blood pressure in all dogs so studied, though this rise was mild in some animals. This finding may explain in part the hypertension exhibited by patients in the recovery room who may have been overtransfused. A norepinephrine drip usually produced an increase in right atrial, wedge, left atrial and systemic arterial blood pressure (p < .01). When there was a significant rise in right atrial pressure and left atrial pressure, the maximum increase in left atrial pressure was always greater than the maximum increase in right atrial pressure (p < .005). This finding again emphasizes the fact that blood transfusion requirements cannot always be accurately assessed on the basis of right and left atrial pressure measurements when a vasopressor agent is being administered. Positive pressure ventilation increased both right and left atrial pressures, as expected. It was again confirmed that pulmonary wedge pressure, as measured with the Swan-Ganz catheter, is approximately equal to left atrial pressure over a wide range of induced variations. The Swan-Ganz catheter, introduced at the bedside in the intensive care unit when necessary, can provide highly useful information regarding left atrial pressure and left ventricular end-diastolic pressure.

Animals↗
PubMed1974

Raised intracranial pressure and cerebral blood flow. 3. Venous outflow tract pressures and vascular resistances in experimental intracranial hypertension.

Pressure changes within the venous outflow tract from the brain were studied in anaesthetized baboons. Segmental vascular resistance changes were also calculated and the results correlated with the changes in cerebral blood flow, measured by the (133)Xenon clearance method. Three different methods were used to raise intracranial pressure: cisterna magna infusion, a supratentorial subdural balloon, and an infratentorial subdural balloon. A close correlation was found between the cortical vein pressure and intracranial pressure with all methods of raising intracranial pressure: the overall correlation coefficient was 0·98. In the majority of animals sagittal sinus pressure showed little change through a wide range of intracranial pressure. In three of the six animals in the cisterna magna infusion group, however, sagittal sinus pressure increased to levels approaching the intracranial pressure during the later stages of intracranial hypertension. Jugular venous pressure showed little change with increasing intracranial pressure. The relationship between cerebral prefusion pressure and cerebral blood flow differed according to the method of increasing intracranial pressure. This was due to differing patterns of change in prevenous vascular resistance as venous resistance increased progressively with increasing pressure in all three groups. The present results confirm, therefore, the validity of the current definition of cerebral perfusion pressure-that is, cerebral perfusion pressure is equal to mean arterial pressure minus mean intracranial pressure-by demonstrating that intracranial pressure does represent the effective cerebral venous outflow pressure.

Animals↗
PubMed2000

Pulse pressure not mean pressure determines cardiovascular risk in older hypertensive patients.

BACKGROUND: Current guidelines for the management of hypertension rest almost completely on the measurement of systolic and diastolic blood pressure. However, the arterial blood pressure wave is more correctly described as consisting of a pulsatile (pulse pressure) and a steady (mean pressure) component. OBJECTIVE: To explore the independent roles of pulse pressure and mean pressure as determinants of cardiovascular prognosis in older hypertensive patients. METHODS: This meta-analysis, based on individual patient data, pooled the results of the European Working Party on High Blood Pressure in the Elderly trial (n = 840), the Systolic Hypertension in Europe Trial (n = 4695), and the Systolic Hypertension in China Trial (n = 2394). The relative hazard rates associated with pulse pressure and mean pressure were calculated using Cox regression analysis, with stratification for the 3 trials and with adjustments for sex, age, previous cardiovascular complications, smoking, and treatment group. RESULTS: A 10-mm Hg wider pulse pressure increased the risk of major cardiovascular complications; after controlling for mean pressure and the other covariates, the increase in risk ranged from approximately 13% for all coronary end points (P = .02) to nearly 20% for cardiovascular mortality (P = .001). In a similar analysis, mean pressure predicted the incidence of cardiovascular complications but only after removal of pulse pressure as an explanatory variable from the model. Furthermore, the probability of a major cardiovascular end point increased with higher systolic blood pressure; at any given level of systolic blood pressure, it also increased with lower diastolic blood pressure, suggesting that the wider pulse pressure was driving the risk of major complications. CONCLUSIONS: In older hypertensive patients, pulse pressure not mean pressure is the major determinant of cardiovascular risk. The implications of these findings for the management of hypertensive patients should be further investigated in randomized controlled outcome trials in which the pulsatile component of blood pressure is differently affected by antihypertensive drug treatment.

Aged↗
PubMed1987

Reproducibility and predictive values of routine blood pressure measurements in children. Comparison with adult values and implications for screening children for elevated blood pressure.

A study of the variability of blood pressure was conducted among a total of 780 Massachusetts children, 335 children in East Boston and 445 children in Brookline, ages 8-18 years. All children had their blood pressure measured with a standard mercury sphygmomanometer in a school setting on four visits one week apart with three measurements per visit. In East Boston, repeat measurements were made for the same children for four consecutive years. A nested random effects model was used to estimate between- and within-visit variance components. For children aged 8-12 years, these were, respectively, 33.1, 12.0 in boys and 31.2, 11.1 in girls for systolic blood pressure and 57.7, 21.3 in boys and 56.6, 22.6 in girls for systolic muffling blood pressure (Korotkoff phase 4). For children aged 13-18 years of age, they were, respectively, 41.1, 11.8 in boys and 35.2, 12.2 in girls for blood pressure and 40.6, 15.5 in boys and 36.1, 11.4 in girls for diastolic blood pressure (Korotkoff phase 5). Within-person variability for systolic pressure was comparable to previously published data for 434 white adults ages 30-49 years not on antihypertensive medications; however, within-person variability for diastolic pressure was considerably higher in the children, accounting for over 75% of total variability among 8-12-year-old children, compared with 27% for adults. No meaningful effects of age, sex, or blood pressure level on variability of systolic pressure were found. However, age and level of blood pressure each had a large and independent inverse association with variability of diastolic pressure; variance components for younger children (ages 8-12 years) and children with low diastolic pressure (less than 60 mmHg) were approximately twice as large as for older children (ages 13-18 years) and children with diastolic pressure greater than or equal to 60 mmHg, respectively. Finally, predictive value estimates of blood pressure are provided for particular age-sex groups to enable one to efficiently identify children whose true mean level of blood pressure exceeds the 90th percentile for their age-sex group with minimum misclassification. Because of the substantial variability of diastolic pressure in young children, resulting in relatively low predictive value estimates, systolic pressure (either alone or in combination with diastolic pressure) may be more useful as the primary tool for screening children under age 13 years for high blood pressure.

Adolescent↗
PubMed2003

Pressure mapping systems: reliability of pressure map interpretation.

BACKGROUND: Pressure mapping systems offer a new technology to assist with pressure care assessment. Data output from such systems can be presented in three forms: numerical data, a three-dimensional grid and a colour-coded pressure map. OBJECTIVES: To (1) investigate whether sole use of the pressure map was a reliable method of interpreting interface pressures when compared with use of the numerical data; (2) establish the inter- and intra-rater reliability of using pressure maps to assess pressure and determine whether reliability depended upon system operator experience; and (3) examine whether reliability extended to the range of seating surfaces being tested. DESIGN: A reliability study assessing the ranking of pressure maps recorded by the Force Sensing Array pressure mapping system. SETTING: A university occupational therapy department and a community NHS trust. SUBJECTS: Fifteen occupational therapists with experience in pressure mapping and 50 occupational therapy students with no practical experience of pressure mapping. INTERVENTIONS: Two sets of pressure maps were pre-recorded with an able-bodied adult seated on a variety of surfaces, with maps on each individual surface recorded over a 20-minute period at 2-minute intervals. Subjects ranked both sets of maps in terms of 'best to poorest' distribution of pressure. MAIN OUTCOME MEASURES: Rank orders of (1) pressure maps; (2) average interface pressures (mmHg); (3) maximum interface pressures (mmHg). RESULTS: The use of pressure maps to interpret interface pressures was a reliable method. Significant agreement existed within (p < 0.001) and between groups of operators and reliability extended over the range of seating surfaces tested. CONCLUSIONS: The practice of using pressure maps to interpret interface pressures in seating as opposed to using the associated numerical data can be supported. This was shown to be a reliable method of assessment by both experienced and less experienced operators across a range of seating surfaces.

Adult↗
PubMed1990

Coronary zero flow pressure and intramyocardial pressure in transiently arrested heart.

STUDY OBJECTIVE: The aim of the study was to examine the relation between zero flow pressure and intramyocardial pressure in the inner and outer layers of the myocardium. DESIGN: Zero flow pressure was obtained in maximally vasodilated excised hearts by decreasing perfusion pressure (at 2 mm Hg.s-1) during transient heart arrest. Intramyocardial pressures in inner and outer myocardium were measured simultaneously with needle tip pressure transducers at depths of 8.0(SD 2.6) and 3.3(1.2) mm from the epicardium respectively. Ventricular and atrial pressure could be controlled at will. EXPERIMENTAL MATERIAL: The excised hearts of eight mongrel dogs, body weight 14.0(0.8) kg, were used. MEASUREMENTS AND MAIN RESULTS: During left ventricular pressure elevation (0, 15, 30 mm Hg), zero flow pressures were 9.1(2.4), 13.8(2.2), and 19.1(5.1) mm Hg, respectively. Corresponding values of intramyocardial pressure at the outer myocardium were in good agreement with the zero flow pressures, at 9.1(3.4), 13.4(2.8), and 20.8(5.4) mm Hg. Values at the inner myocardium increased from 7.4(2.4) to 18.9(8.6) and 32.9(13.0) mm Hg. The latter two values were significantly higher than the corresponding values of zero flow pressure and intramyocardial pressure at the outer myocardium (p less than 0.05, p less than 0.01). In isotransmural pressure elevation, the three pressures increased almost equally. CONCLUSIONS: The results show that zero flow pressure is strongly affected by intramyocardial tissue pressure, and if uneven intramyocardial pressure distribution is present the value of zero flow pressure depends on the lower values of intramyocardial pressure.

Animals↗
PubMed1991

Blood pressure and high blood pressure. Aspects of risk.

This report deals with three aspects of risk related to blood pressure and high blood pressure. The first aspect of risk concerns distributions of systolic blood pressure (SBP) and diastolic blood pressure (DBP) in the adult population and their relation to long-term risk of morbidity and mortality. By middle age, only a minority (about 20%) of Americans have optimal SBP and DBP levels, less than 120 mm Hg and less than 80 mm Hg, respectively. For the majority with higher levels, risks of major clinical events, including death from cardiovascular diseases and from all causes, are markedly increased. The relations of SBP and DBP with risk are strong, continuous, and graded. Risk is sizable not only for persons with high blood pressure by usual clinical criteria (SBP greater than or equal to 140 mm Hg or DBP greater than or equal to 90 mm Hg), but also for those with "high-normal" blood pressure (e.g., SBP 130-139 mm Hg or DBP 80-89 mm Hg). Thus, the blood pressure problem is a population-wide one and requires for its control a combined population-wide and high-risk strategy. A major component of this strategy must be nutritional-hygienic measures for the primary prevention of the rise in blood pressure during adulthood and of high blood pressure (i.e., primary prevention not only of the complications of high blood pressure but also of high blood pressure itself) through improved lifestyles having the potential to shift downward the blood pressure distribution of the whole population. The second aspect of risk concerns the known risk factors (i.e., aspects of modern lifestyle) leading to the mass occurrence of blood pressure rise during adulthood and of high blood pressure. These risk factors are high salt intake, high dietary sodium/potassium ratio, calorie imbalance and resultant obesity, and high alcohol intake. The extensive data base establishing the role of these common traits in the etiology of the blood pressure/high blood pressure problem is the scientific foundation for efforts to achieve the primary prevention of high blood pressure. The third aspect of risk relates to the combined impact of other risk factors along with blood pressure-high blood pressure in markedly increasing the probabilities of morbidity and mortality (e.g., "rich" diet, diet-dependent serum cholesterol and uric acid, smoking, diabetes, and target-organ damage). Prevention and control of lifestyle-related traits are essential components of the strategy for dealing with the blood pressure-high blood pressure problem.

Blood Pressure↗
PubMed1989

The pressures in the episcleral veins, Schlemm's canal and the trabecular meshwork in monkeys: effects of changes in intraocular pressure.

The pressures in the episcleral veins, Schlemm's canal and the trabecular meshwork were studied with a micropuncture technique using cannulas with tip diameters of less than 5 microns. The pressure in Schlemm's canal, Psc, was 14.3 +/- 1.0 cmH2O at spontaneous intraocular pressure, IOP, 19.2 +/- 0.9 cmH2O. The outflow pressure from the anterior chamber to Schlemm's canal was 4.9 +/- 0.7 cmH2O. The relationship between pressures was IOP = 0.73 Psc + 8.7. When the intraocular pressure was increased stepwise from the spontaneous level to 30 cmH2O there was an increase in pressure in Schlemm's canal of 1.7 +/- 0.6 cmH2O, (P less than 0.05). The total outflow resistance and the resistance between the anterior chamber and Schlemm's canal were 3.27 +/- 0.43 and 2.92 +/- 0.50 cmH2O min microliter-1 respectively for the intraocular pressure interval between the spontaneous pressure and a level 4-11 cmH2O higher. In the intraocular pressure range from 20 to 30 cmH2O the corresponding figures were 2.89 +/- 0.45 and 2.69 +/- 0.42 cmH2O min microliter-1 and for the pressure range 25-35 cmH2O, 2.48 +/- 0.58 and 2.31 +/- 0.59 cmH2O min microliter-1. The difference between the total outflow resistance and that between the anterior chamber and Schlemm's canal was about 10% of the total at intraocular pressures below 35 cmH2O. Stepwise increments in IOP increased the trabecular meshwork pressure by 0.88 cmH2O for each cmH2O increase in IOP in the interval of 30-50 cmH2O. The total outflow resistance and the resistance between the anterior chamber and the tip of the microcannula was 3.91 +/- 1.53 and 1.94 +/- 0.99 cmH2O min microliter-1 respectively for the intraocular pressure interval between the spontaneous pressure and 30 cmH2O. In the interval between 30 and 45 cmH2O the corresponding figures were 2.16 +/- 0.66 and 0.20 +/- 0.13 cmH2O min microliter-1. The episcleral venous pressure at the spontaneous intraocular pressure was 14.1 +/- 1.0 cmH2O in seven animals with minimal trauma, and 12.3 +/- 0.8 cmH2O in animals after cannulation of Schlemm's canal. The outflow pressure from the anterior chamber to the episcleral veins was 4.4 +/- 1.2 cmH2O in animals with minimal trauma and 7.1 +/- 0.8 cmH2O after cannulation of Schlemm's canal. The relationship between pressures was IOP = 0.68EVP + 11.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1998

Discrepancy between screening blood pressure and ambulatory blood pressure: a community-based study in Ohasama.

We investigated factors underlying discrepancy between screening blood pressure and daytime ambulatory blood pressure (the difference) in a community-based population in northeastern Japan. Screening and ambulatory pressures were measured in 706 untreated subjects aged 20 yr or older. We analyzed the effects of age and blood pressure on the difference and then performed multivariate stepwise linear regression analysis using the difference as the dependent variable. The systolic difference positively correlated with age in men. Women in their 40s exhibited a large difference, disturbing the linear relationship between the difference and age. The difference positively correlated with the screening pressure in men and women. A positive difference (screening pressure > ambulatory pressure) was observed at screening pressures above 130/75 mmHg. The difference inversely correlated with the ambulatory pressure. Multivariate analysis demonstrated that body mass index and male sex were positively associated with the systolic and diastolic blood pressure differences. The daytime pulse rate was negatively associated with the systolic difference, and the standard deviation of daytime diastolic ambulatory blood pressure was positively associated with the diastolic difference. The diastolic difference in subjects with isolated systolic hypertension based on the screening pressure was significantly smaller than that in subjects with systolic/diastolic hypertension. The difference in subjects with isolated systolic hypertension based on ambulatory pressure was significantly higher than that in systolic/diastolic hypertension. When white-coal (isolated screening) hypertension was defined as a screening systolic pressure > or = 140 mmHg, a diastolic pressure > or = 90 mmHg, or both, and a 24-h ambulatory pressure < 136/87 mmHg in men and < 131/86 mmHg in women, white-coat (isolated screening) hypertension was present in 79 (56.8%) of 139 subjects with screening hypertension. The results confirm that the discrepancy between screening and ambulatory blood pressure is due to a variety of factors, including age, sex, blood pressure levels, and baroreflex function. Our results indicate that screening blood pressure in elderly hypertensive patients should be evaluated carefully.

Adult↗
PubMed1995

A comparison of stress leak-point pressure and maximal urethral closure pressure in patients with genuine stress incontinence.

OBJECTIVE: To determine the correlation between the maximal urethral closure pressure and the stress leak-point pressure in patients with genuine stress incontinence, and to define a critical stress leak-point pressure value to detect patients with a low-pressure urethra, as defined by a maximal urethral closure pressure less than 20 cm H2O. METHODS: Fifty-nine patients with genuine stress incontinence were evaluated prospectively with multichannel urodynamics. Maximal urethral closure pressures and stress leak-point pressures were determined and correlated. Several stress leak-point pressure values were evaluated by contingency tables to detect a critical level for detecting a low-pressure urethra. RESULTS: There is a statistically significant relationship (P < .0001) between the stress leak-point pressure and the maximal urethral closure pressure. However, a correlation coefficient of 0.56 demonstrates poor clinical relationship. A stress leak-point pressure less than or equal to 45 cm H2O was found to be 80% sensitive and 90% specific in diagnosing a low-pressure urethra. A stress leak-point pressure less than or equal to 60 cm H2O was 90% sensitive and 64% specific in detecting a low-pressure urethra. CONCLUSIONS: The stress leak-point pressure has poor clinical correlation to the maximal urethral closure pressure. A stress leak-point pressure less than or equal to 45 cm H2O has adequate sensitivity and specificity to diagnose a low-pressure urethra. A value less than or equal to 60 cm H2O would be an appropriate cutoff level to screen for those patients at risk of having a low-pressure urethra in need of further evaluation.

Adult↗
PubMed1996

Tracheal pressure triggering a demand-flow continuous positive airway pressure system decreases patient work of breathing.

OBJECTIVES: Triggering a ventilator "ON" at the carinal end of the endotracheal tube decreases imposed work of breathing by bypassing the resistance imposed by the breathing circuit and the endotracheal tube. We compared work of breathing during spontaneous ventilation between three methods of triggering the ventilator "ON": a) conventional pressure triggering from inside the ventilator; b) flow-by triggering; or c) tracheal pressure triggering at the carinal end of the endotracheal tube. We hypothesized that the work of breathing would be substantially decreased with tracheal pressure triggering compared with conventional pressure and flow-by methods in patients receiving continuous positive airway pressure. DESIGN: Clinical, prospective study. SETTING: University teaching hospital. PATIENTS: Fourteen adults diagnosed with acute respiratory failure. INTERVENTIONS: All patients were breathing spontaneously at an FIO2 of 0.30 to 0.40 and received 5 cm H2O of continuous positive airway pressure. Three different methods of triggering the ventilator while set in the continuous positive airway pressure mode were administered in random order. MEASUREMENTS AND MAIN RESULTS: Real-time measurements of esophageal pressure and tidal volume were integrated with a respiratory monitor (CP-100, Bicore, Riverside, CA) that uses the Campbell diagram to calculate total work of breathing. Imposed work of breathing was calculated by integrating tidal volume with the pressure at the carinal end of the endotracheal tube. Physiologic work of breathing was calculated by subtracting imposed work of breathing from the total work of breathing. Breathing frequency, the index of rapid shallow breathing (breathing frequency/tidal volume), peak inspiratory flow rate demand, exhaled minute ventilation, and the duration of respiratory muscle contraction assessed by the ratio of inspiratory time to total cycle time were also measured. Data were analyzed by Friedman's repeated-measures analysis of variance on ranks. Alpha was set at .05 for statistical significance. Imposed work of breathing decreased to approximately zero during tracheal pressure triggering. As a result, total work of breathing decreased by approximately 40% compared with the flow-by and conventional methods. During tracheal pressure triggering only, airway pressure increased above baseline pressure to approximately 11 cm H2O, which resembled pressure-support ventilation. Also, during tracheal pressure triggering, tidal volume and peak inspiratory flow rate were significantly increased, while the pressure-time product and the index of rapid shallow breathing were significantly decreased. Hemodynamic status and oxygen saturation were not clinically affected. CONCLUSIONS: The tracheal pressure triggering of a demand-flow continuous positive airway pressure system creates an effect similar to pressure-support ventilation that significantly decreases imposed work of breathing and, thus, total work of breathing. We recommend moving the triggering site of the ventilator to the carinal end of the endotracheal tube.

Acute Disease↗