Biomedical subjects

Samir Jaber

Publications and source records attributed to Samir Jaber.

At least 19 recordsLinked to original sources

PubMed2006

Noninvasive ventilation improves preoxygenation before intubation of hypoxic patients.

RATIONALE: Critically ill patients are predisposed to oxyhemoglobin desaturation during intubation. OBJECTIVES: To find out whether noninvasive ventilation (NIV), as a preoxygenation method, is more effective at reducing arterial oxyhemoglobin desaturation than usual preoxygenation during orotracheal intubation in hypoxemic, critically ill patients. METHODS: Prospective randomized study performed in two surgical/medical intensive care units (ICUs). Preoxygenation was performed, before a rapid sequence intubation, for a 3-min period using a nonrebreather bag-valve mask (control group) or pressure support ventilation delivered by an ICU ventilator through a face mask (NIV group) according to the randomization. MEASUREMENTS AND MAIN RESULTS: The control (n = 26) and NIV (n = 27) groups were similar in terms of age, disease severity, diagnosis at admission, and pulse oxymetry values (Sp(O(2))) before preoxygenation. At the end of preoxygenation, Sp(O(2)) was higher in the NIV group as compared with the control group (98 +/- 2 vs. 93 +/- 6%, p < 0.001). During the intubation procedure, the lower Sp(O(2)) values were observed in the control group (81 +/- 15 vs. 93 +/- 8%, p < 0.001). Twelve (46%) patients in the control group and two (7%) in the NIV group had an Sp(O(2)) below 80% (p < 0.01). Five minutes after intubation, Sp(O(2)) values were still better in the NIV group as compared with the control group (98 +/- 2 vs. 94 +/- 6%, p < 0.01). Regurgitations (n = 3; 6%) and new infiltrates on post-procedure chest X ray (n = 4; 8%) were observed with no significant difference between groups. CONCLUSION: For the intubation of hypoxemic patients, preoxygenation using NIV is more effective at reducing arterial oxyhemoglobin desaturation than the usual method.

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PubMed2006

Performance characteristics of five new anesthesia ventilators and four intensive care ventilators in pressure-support mode: a comparative bench study.

BACKGROUND: During the past few years, many manufacturers have introduced new modes of ventilation in anesthesia ventilators, especially partial-pressure modalities. The current bench test study was designed to compare triggering and pressurization of five new anesthesia ventilators with four intensive care unit ventilators. METHODS: Ventilators were connected to a two-compartment lung model. One compartment was driven by an intensive care unit ventilator to mimic "patient" inspiratory effort, whereas the other was connected to the tested ventilator. The settings of ventilators were positive end-expiratory pressures of 0 and 5 cm H2O, and pressure-support ventilation levels of 10, 15, and 20 cm H2O with normal and high "patient" inspiratory effort. For the anesthesia ventilators, all the measurements were obtained for a low (1 l/min) and a high (10 l/min) fresh gas flow. Triggering delay, triggering workload, and pressurization at 300 and 500 ms were analyzed. RESULTS: For the five tested anesthesia ventilators, the pressure-support ventilation modality functioned correctly. For inspiratory triggering, the three most recent anesthesia machines (Fabius, Drägerwerk AG, Lübeck, Germany; Primus, Drägerwerk AG; and Avance, GE-Datex-Ohemda, Munchen, Germany) had a triggering delay of less than 100 ms, which is considered clinically satisfactory and is comparable to intensive care unit machines. The use of positive end-expiratory pressure modified the quality of delivered pressure support for two anesthesia ventilators (Kion, Siemens AG, Munich, Germany; and Felix, Taema, Antony, France). Three of the five anesthesia ventilators exhibited pressure-support ventilation performance characteristics comparable to those of the intensive care unit machines. Increasing fresh gas flow (1 to 10 l/min) in the internal circuit did not influence the pressure-support ventilation performance of the anesthesia ventilators. CONCLUSION: Regarding trigger sensitivity and the system's ability to meet inspiratory flow during pressure-supported breaths, the most recent anesthesia ventilators have comparable performances of recent-generation intensive care unit ventilators.

Anesthesia, Inhalation↗

PubMed2006

Impact of systematic evaluation of pain and agitation in an intensive care unit.

OBJECTIVE: To measure the impact of implementation of the systematic evaluation of pain and agitation by nurses using the Behavioral Pain Scale (BPS), the Numerical Rating Scale (NRS) for pain, and the Richmond Agitation Sedation Scale (RASS) associated with medical staff education in analgesia and sedation management in intensive care unit (ICU) patients. DESIGN: Two-phase, prospective, controlled study. SETTING: Twelve-bed medical-surgical ICU in a university hospital. PATIENTS: Consecutive patients staying >24 hrs in ICU. INTERVENTIONS: BPS, NRS, and RASS were measured twice daily, at rest, by independent observers during 21 wks (control group) and after 4 wks of training, by nurses during 29 wks (intervention group). In the intervention group, the treating physician was alerted in case of pain defined by BPS>5 or NRS>3 or in case of agitation defined by RASS>1. MEASUREMENTS AND MAIN RESULTS: A total of 230 patients were included (control group, n=100; intervention group, n=130). Baseline characteristics were not significantly different. The incidence of pain and agitation decreased significantly in the intervention group: 63% vs. 42% (p=.002) and 29% vs. 12% (p=.002), respectively. Rate of severe pain and agitation events defined by NRS>6 and RASS>2, respectively, also decreased significantly. There were significantly more therapeutic changes in the intervention group in the way of an escalation but also in the way of a de-escalation for analgesic and psychoactive drugs. Compared with the control group, there was a marked decrease in the duration of mechanical ventilation (120 [interquartile range 48-312] vs. 65 (24-192) hrs, p=.01) and nosocomial infections rate (17% vs. 8%, p<.05) in the intervention group. There was no significant difference in median length of stay (9 [4, 15] vs. 7 [4, 13] days) and mortality in ICU (12 vs. 15%). CONCLUSIONS: Systematic evaluation of pain and agitation, and analgesics and sedatives need was associated with a decrease in incidence of pain and agitation, duration of mechanical ventilation and nosocomial infections.

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PubMed2006

Clinical practice and risk factors for immediate complications of endotracheal intubation in the intensive care unit: a prospective, multiple-center study.

OBJECTIVES: To describe the current practice of physicians, to report complications associated with endotracheal intubation (ETI) performed in THE intensive care unit (ICU), and to isolate predictive factors of immediate life-threatening complications. DESIGN: Multiple-center observational study. SETTING: Seven intensive care units of two university hospitals. PATIENTS: : We evaluated 253 occurrences of ETI in 220 patients. INTERVENTIONS: From January 1 to June 30, 2003, data related to all ETI performed in ICU were collected. Information regarding patient descriptors, procedures, and immediate complications were analyzed. MEASUREMENTS AND MAIN RESULTS: The main indications to intubate the trachea were acute respiratory failure, shock, and coma. Some 148 ETIs (59%) were performed by residents. At least one severe complication occurred in 71 ETIs (28%): severe hypoxemia (26%), hemodynamic collapse (25%), and cardiac arrest (2%). The other complications were difficult intubation (12%), cardiac arrhythmia (10%), esophageal intubation (5%), and aspiration (2%). Presence of acute respiratory failure and the presence of shock as an indication for ETI were identified as independent risk factors for occurrence of complications, and ETI performed by a junior physician supervised by a senior (i.e., two operators) was identified as a protective factor for the occurrence of complications. CONCLUSIONS: ETI in ICU patients is associated with a high rate of immediate and severe life-threatening complications. Independent risk factors of complication occurrence were presence of acute respiratory failure and presence of shock as an indication for ETI. Further studies should aim to better define protocols for intubation in critically ill patients to make this procedure safer.

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PubMed2006

Clinical effects of heliox administration for acute bronchiolitis in young infants.

OBJECTIVE: To assess the effect of heliox, a helium-oxygen mixture, on respiratory distress symptoms in young infants. DESIGN: Prospective, randomized, double-blind study. SETTING: Pediatric ICU (PICU) of a university hospital. PATIENTS: Twenty infants, all < 3 months old, admitted to the PICU with moderate-to-severe acute respiratory syncytial virus bronchiolitis. INTERVENTIONS: All infants were randomly and blindly assigned to inhale either heliox or an air-oxygen mixture (airox) for 1 h under an oxyhood. MEASUREMENTS AND RESULTS: After 1 h, the respiratory distress score was significantly lower in the heliox group compared with the airox group (3.05 vs 5.5, p < 0.01), with a significant reduction in accessory muscles use (p < 0.05) and expiratory wheezing (p < 0.01). In contrast, inspiratory breath sounds and cyanosis did not significantly differ between groups. The ex-premature infants of the heliox group had a higher respiratory distress score at baseline compared with the term infants of this group (5.8 vs 5.2, p < 0.05) and a comparable decrease in the score at 60 min. CONCLUSIONS: In young infants, even those born prematurely, heliox breathing induced a rapid reduction in accessory muscles use and expiratory wheezing. Further studies are needed to confirm the decreased respiratory muscle work of breathing during heliox inhalation in this population.

Acute Disease↗

PubMed2005

Noninvasive positive pressure ventilation in patients with respiratory failure due to severe acute pancreatitis.

BACKGROUND: Patients with acute pancreatitis (AP) who require mechanical ventilation have high morbidity and mortality rates. Noninvasive positive pressure ventilation (NPPV) delivered through a mask has become increasingly popular for the treatment of acute respiratory failure (ARF) and may limit some mechanical ventilation complications. OBJECTIVES: The purpose of this retrospective, observational study was to evaluate our clinical experience with the use of NPPV in AP patients with ARF. METHODS: From 1997 to 2003, we documented clinical data, gas exchange and outcome of the 62 AP patients admitted to our intensive care unit. Patients who benefited from NPPV (success) were compared with those who failed (intubated). RESULTS: Twenty-nine patients were intubated at admission and 5 did not develop ARF. Of the 28 patients treated with NPPV, 15 were not intubated (54%). Both groups had a similar PaO(2)/FiO(2) ratio (142 +/- 21 vs. 133 +/- 20; p = 0.127) and severity of illness (Ranson and Balthazar scores). Presence of atelectasis, bilateral alveolar infiltrates and abdominal distension were associated with failure of NPPV. Oxygenation improved and respiratory rate decreased significantly only in the success group. Additionally, the length of stay at the intensive care unit was significantly lower in the success group. CONCLUSION: NPPV is feasible and safe to treat ARF in selected patients with AP who require ventilatory support.

Abdomen↗

PubMed2005

[Managing the complications of cirrhosis].

The main complications of cirrhosis are gastrointestinal bleeding related to portal hypertension, ascites, spontaneous peritonitis, hepato-renal syndrome, encephalopathy and hepatocellular carcinoma. The apparition of these complications constitutes a major event for the patient. In addition to the etiological treatment, take charge of complications can improve the prognosis of the patients.

Ascites↗

PubMed2005

Effects of short vs. prolonged mechanical ventilation on antioxidant systems in piglet diaphragm.

OBJECTIVE: Prolonged controlled mechanical ventilation (MV) is known to induce diaphragmatic oxidative stress that seems to be an important factor reducing force-generating capacity. To better understand the cellular mechanisms involved, this work examined the effect of short vs. prolonged MV on antioxidant defense in the diaphragm. DESIGN AND SETTING: Prospective, randomized, controlled animal study in a university laboratory. METHODS: Eleven piglets (15-20 kg) were assigned to one of two groups: a long-MV group (n=6) ventilated for 3 days or a short-MV group (n=5) ventilated for 3 h. Force frequency curves of the transdiaphragmatic pressure (Pdi) were obtained in vivo by phrenic nerve pacing. Oxidative stress was evaluated by thiobarbituric reactive substance (TBARs) content and the enzymatic antioxidant activity of both superoxide dismutase (SOD) and glutathione peroxidase (GPx) in samples of diaphragm. RESULTS: Pdi decreased in the long-MV group by 30-35% over the 3 days at all frequencies compared to the short-MV group. Diaphragm TBARs content was significantly higher and SOD activity lower in long-MV animals than in short-MV animals after 72 h. GPx activity tended to be lower in diaphragms from long-MV animals, but this difference was not significant. CONCLUSIONS: This study shows that 3 days of MV in piglets is associated with a decrease in antioxidant activity which could emphasize oxidative stress and both contribute to the diaphragm dysfunction caused by MV.

Animals↗

PubMed2005

Volume-guaranteed pressure-support ventilation facing acute changes in ventilatory demand.

OBJECTIVE: To compare volume support ventilation (VSV) in which the pressure support level is continuously adjusted to deliver a preset tidal volume, with pressure support ventilation (PSV), in terms of patient behavior and ventilator response when ventilatory demand was increased by addition of dead space to the circuit. DESIGN AND SETTING: Randomized cross-over study in an intensive care unit university hospital. INTERVENTIONS: We assessed in ten patients being weaned off mechanical ventilation the effect of increasing the ventilatory demand by adding a heat-and-moisture exchanger to augment the dead space with a fixed level of PSV and VSV. MEASUREMENTS AND RESULTS: Arterial blood gases, breathing pattern, and respiratory effort parameters at the end of each of the four steps. Adding dead space significantly increased minute ventilation and PaCO2 values with both PSV and VSV. Indexes of respiratory effort (pressure-time index of respiratory muscles and work of breathing) increased with both ventilatory modes after dead-space augmentation. This increase was 2.5-4 times with VSV than with PSV and induced overt respiratory distress in two patients. The assistance delivered during VSV decreased significantly after dead-space augmentation, from 15.0+/-6.5 to 9.1+/-4.8 cmH2O, whereas no change occurred with PSV. CONCLUSIONS: With a fixed level of VSV, but not of PSV, an increase in ventilatory demand results in a decrease in the pressure support provided by the ventilator, opposite to the desired response. VSV may conceivably result in respiratory distress in clinical settings.

APACHE↗

PubMed2005

Changes in respiratory muscle endurance during puberty.

The evaluation of respiratory muscle endurance provides clinically useful information on muscle function, especially in children with respiratory and neuromuscular diseases. However, endurance may be lower in young children than in older children because of the major physical changes of puberty. We thus compared respiratory muscle endurance in 15 healthy pre- and peripubertal children (S1-S2/P1 group) and 14 healthy children near the end of the pubertal process (S4P4 group). All performed a respiratory muscle endurance test threshold load fixed at 50% of the individual maximal inspiratory pressure; (Pi(max)), using a standardized method with a controlled breathing pattern. No significant difference was found between groups for Pi(max). The mean endurance time limit for the S1-S2/P1 group was 138 +/- 20 sec. The S4P4 group was able to breathe with the threshold valve for more than 20 min (1,200 sec) without task failure, except for one girl (385 sec). This study shows that inspiratory muscle endurance is significantly lower in children in early puberty compared to children at the end of the pubertal process. If the underlying mechanisms are not well-known, the present study revealed that if we use the same inspiratory load in prepubertal children as in adults during clinical testing, we are likely to underestimate the susceptibility to task failure of their respiratory muscles. To define a fatigue threshold for the respiratory muscles, as a function of age, thus appears clinically important in further studies, particularly for the management of children with respiratory diseases.

Adolescent↗

PubMed2005

Are preoperative patterns of alcohol consumption predictive of relapse after liver transplantation for alcoholic liver disease?

Predictive factors for alcoholic relapse after liver transplantation (LT) performed for alcoholic liver disease (ALD) have been assessed in numerous studies, often with contradictory results. The aim of the study was to assess pretransplantation alcohol consumption characteristics on alcoholic relapse after LT. Patients transplanted for ALD for at least 6 months were included. An anonymous questionnaire assessed socio-demographic characteristics, medical history, and alcohol consumption before and after LT. Relapse was defined as any alcohol use after LT. Severe relapse was defined by heavy drinking: more than 21 units/week for males and 14 units/week for females. A total of 61 patients were studied. The mean follow up after LT was 49 +/- 34 months. Alcoholic relapse occurred in 32 of 61 patients (52%) and severe relapse in eight of 61 patients (13%). Risk factors for severe relapse were: length of abstinence before LT (P = 0.0001), more than one alcohol withdrawal before LT (P = 0.001), alcohol dependence (P = 0.05), alcohol abuse in first relatives (P = 0.05), and younger age (P = 0.05). Information on previous alcohol consumption (dependence, number of withdrawals, family history) helps to predict severe relapse after LT in patients with ALD, allowing early awareness and specific postoperative care.

Alcohol Drinking↗

PubMed2005

Cytomegalovirus infection in critically ill patients: associated factors and consequences.

OBJECTIVE: To determine the prevalence, associated findings, and consequences of cytomegalovirus (CMV) antigenemia in critically ill patients. DESIGN: A retrospective, case-control clinical study. SETTING: A 12-bed university hospital medical-surgical ICU. PATIENTS: Two hundred thirty-seven patients with fever for > 72 h, without proven evidence of bacteriologic and/or fungal origin, and whose pp65 antigenemia assays were studied. Patients with HIV infection and transplant recipients were excluded. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: CMV antigenemia was diagnosed within 20 +/- 12 days (mean +/- SD) after ICU admission in 17% patients in whom the pathology was suspected. The 40 patients in the CMV group were matched with 40 other patients in the control group. CMV infection was linked to renal failure (58% vs 33%, respectively; p = 0.02) and steroid use (55% vs 33%, respectively; p = 0.04). Patients with CMV had a significantly longer stay in the ICU (41 +/- 28 days vs 31 +/- 22 days, respectively; p = 0.04), a longer duration of mechanical ventilation (35 +/- 27 days vs 24 +/- 20 days, respectively; p = 0.03), a higher rate of nosocomial infection (75% vs 50%, respectively; p = 0.04), and a higher mortality (50% vs 28%, p = 0.02). CONCLUSIONS: CMV antigenemia is not an uncommon diagnosis in critically ill ICU patients with unexplained prolonged fever after 10 days of hospitalization, regardless of their immune system status. Although associated with a higher morbidity and mortality, the clinical significance of CMV is unknown. Further prospective studies should evaluate the impact on ICU outcome and whether CMV is truly a pathogen or simply another indicator of immunosuppression.

Adult↗

PubMed2005

Performance characteristics of 10 home mechanical ventilators in pressure-support mode: a comparative bench study.

OBJECTIVE: Inspiratory pressure (Pi) support delivered by a bilevel device has become the technique of choice for noninvasive home ventilation. Considerable progress has been made in the performance and functionality of these devices. The present bench study was designed to compare the various characteristics of 10 recently developed bilevel Pi devices under different conditions of respiratory mechanics. DESIGN: Bench model study. SETTING: Research laboratory, university hospital. MEASUREMENTS: Ventilators were connected to a lung model, the mechanics of which were set to normal, restrictive, and obstructive, that was driven by an ICU ventilator to mimic patient effort. Pressure support levels of 10 and 15 cm H(2)O, and maximum were tested, with "patient" inspiratory efforts of 5, 10, 15, 20, and 25 cm H(2)O. Tests were conducted in the absence and presence of leaks in the system. Trigger delay, trigger-associated inspiratory workload, pressurization capabilities, and cycling were analyzed. RESULTS: All devices had very short trigger delays and triggering workload. Pressurization capability varied widely among the machines, with some bilevel devices lagging behind when faced with a high inspiratory demand. Cycling was usually not synchronous with patient inspiratory time when the default settings were used, but was considerably improved by modifying cycling settings, when that option was available. CONCLUSIONS: A better knowledge of the technical performance of bilevel devices (ie, pressurization capabilities and cycling profile) may prove to be useful in choosing the machine that is best suited for a patient's respiratory mechanics and inspiratory demand. Clinical algorithms to help set cycling criteria for improving patient-ventilator synchrony and patient comfort should now be developed.

Humans↗

PubMed2005

Outcomes of patients with acute respiratory failure after abdominal surgery treated with noninvasive positive pressure ventilation.

OBJECTIVES: Little is known about the physiologic and clinical effects of noninvasive positive pressure ventilation (NPPV) in patients who have acute respiratory failure (ARF) after abdominal surgery. We evaluated our clinical experience with the use of NPPV in the treatment of ARF after abdominal surgery. METHODS: We prospectively evaluated NPPV use during a 2-year period in a medical-surgical ICU of a university hospital. We documented demographic and diagnostic data, gas exchange, and clinical outcomes. We compared patients who were not intubated to those who were intubated after a trial of NPPV. RESULTS: Of 72 patients with ARF after abdominal surgery who were treated with NPPV, 48 patients avoided intubation (67%). Patients in the intubated and nonintubated groups had similar demographic characteristics, and similar American Society of Anesthesiologists physical status and simplified acute physiology score II scores at admission. The intubated group had a significantly lower Pa(O2)/fraction of inspired oxygen (Fi(O2)) ratio (123 +/- 62 mm Hg vs 194 +/- 76 mm Hg, p < 0.01) and more extended bilateral alveolar infiltrates (67% vs 31%, p < 0.01) than the non-intubated group. Within the first NPPV observation period, the Pa(O2)/Fi(O2) increased (+ 36 +/- 29% [+/- SD], p = 0.04) and the respiratory rate decreased (28.2 +/- 3.4 breaths/min vs 23.1 +/- 3.8 breaths/min, p < 0.01) significantly only in the non-intubated group. The non-intubated group had significantly lower length of ICU stay (17.3 +/- 10.9 days vs 34.1 +/- 28.5 days, p < 0.01) and mortality rate (6% vs 29%, p < 0.01). CONCLUSION: NPPV may be an alternative to conventional ventilation in selected patients with ARF after abdominal surgery who require ventilatory support.

Abdomen↗

PubMed2005

A prospective study of agitation in a medical-surgical ICU: incidence, risk factors, and outcomes.

STUDY OBJECTIVES: Although agitation is thought to be common in the ICU, it has been poorly studied. We evaluated the incidence, risks factors, and outcomes of agitation in ICU. DESIGN: Prospective observational study. INTERVENTIONS: None. METHOD: All consecutive ICU admissions over an 8-month period were analyzed. MEASUREMENTS AND RESULTS: Two hundred eleven patients were admitted a total of 216 times during the period of the study. Twenty-nine patients were excluded from the study because their pathology findings did not allow an evaluation of their level of consciousness; 182 patients were actually enrolled. Agitation developed in 95 of 182 patients (52%). Agitation began 4.4 +/- 5.6 days (+/- SD) after admission to the ICU and lasted 3.9 +/- 4.1 days. Patients with agitation had a higher Simplified Acute Physiology Score II on ICU admission than those who did not have agitation (40 +/- 16 vs 33 +/- 13, p < 0.01). By stepwise logistic regression, the independent risks factors for development of agitation included psychoactive drug use at the time of ICU admission (odds ratio, 5.63; 95% confidence interval [CI], 1.32 to 23.70), history of alcohol abuse (odds ratio, 3.32; 95% CI, 1.12 to 10.00), dysnatremia (odds ratio, 4.95; 95% CI, 1.95 to 12.54), fever (odds ratio, 4.52; 95% CI, 1.80 to 11.49), use of sedatives in the ICU (odds ratio, 4.03; 95% CI, 1.62 to 10.40), and sepsis (odds ratio, 2.61; 95% CI, 1.03 to 6.58). Agitation was associated with a prolonged ICU stay (16 +/- 19 days vs 6 +/- 6 days, p = 0.0001), nosocomial infections (34% vs 7%, p < 0.0001), unplanned extubations (17% vs 2%, p = 0.003), and unplanned central venous catheter removal (16% vs 1%, p = 0.001), but not with mortality (12% in the agitation group vs 8% in patients without agitation). CONCLUSIONS: Agitation is a common event in a mixed medical-surgical ICU. It is associated with adverse outcomes including prolonged stay, nosocomial infections, and unplanned extubations. A better knowledge of incidence and risk factors should facilitate identification of patients at risk and decrease the incidence of agitation.

Documentation↗

PubMed2005

Elevated plasma cysteinylglycine levels caused by cilastatin-associated antibiotic treatment.

Imipenem (thienamycin formamidine), a broad-spectrum beta-lactam antibiotic, is always used in combination with cilastatin in order to avoid the premature breakdown of imipenem by renal tubular dipeptidase. As this dipeptidase also hydrolyzes the glutathione metabolite cysteinylglycine, the therapeutic association of imipenem and cilastatin might cause an accumulation of the aminothiol cysteinylglycine. We demonstrate here that when patients are treated with imipenem-cilastatin, their plasma levels of cysteinylglycine are significantly and specifically increased, while cysteine levels are decreased and homocysteine levels are unaffected. We conclude that antibiotic treatment using imipenem-cilastatin induces important metabolic changes that should not remain unrecognized.

Anti-Bacterial Agents↗

PubMed2004

Long-term effects of different humidification systems on endotracheal tube patency: evaluation by the acoustic reflection method.

BACKGROUND: Accumulation of mucous secretions in an endotracheal tube (ETT) increases its resistance, and the amount of deposit may be affected by the quality of humidification and heating of the inspired gas. METHODS: The authors assessed the impact of two humidification systems, a heated humidifier (HH) and a hygroscopic-hydrophobic heat and moisture exchanger (HME), on the ETT patency in patients selected to require mechanical ventilation for more than 48 h. This comparison was performed over two consecutive periods and used the acoustic reflection method, which characterizes the amount and site of ETT obstruction and allows estimating ETT inner volume and resistance. Measurements were performed three times a week over the period of mechanical ventilation. Comparisons were performed at mid duration and at the end of the mechanical ventilation period. RESULTS: The HH was used in 34 patients, and the HME was used in 26 patients. The two groups had similar severity and duration of mechanical ventilation. At mid duration of mechanical ventilation (5.5 +/- 3.3 vs. 4.8 +/- 3.3 days; P = 0.4), no difference was observed in ETT volume and resistance between the two groups. At the end of the study period (10.5 +/- 5.8 vs. 9.6 +/- 6.3 days of mechanical ventilation; P = 0.4), ETT volume was reduced to a greater extent with HME than with HH (-3.3 +/- 2.9 vs. -5.1 +/- 2.5%; P = 0.008), and ETT resistance increased significantly more with the HME than with the HH (8.4 +/- 12.2 vs. 19.4 +/- 17.7%; P = 0.001). CONCLUSION: Prolonged use of humidification systems results in progressive reduction of ETT patency, and to a greater extent with HMEs than with HHs.

Adult↗

PubMed2003

Cardiac troponin I in patients with severe exacerbation of chronic obstructive pulmonary disease.

OBJECTIVES: Co-morbid conditions including risk factors for cardiovascular diseases and left ventricular dysfunction are common in patients with chronic obstructive pulmonary disease (COPD). This study assessed the incidence of cardiac troponin I (cTnI) elevation, a specific marker for cardiac injury, and its prognostic significance during severe exacerbation of COPD. DESIGN: Prospective cohort study. SETTING: Two intensive care units. PARTICIPANTS: Seventy-one consecutive patients admitted for severe exacerbation of COPD. INTERVENTION: None. MEASUREMENTS AND RESULTS: Cardiac troponin I was assayed in blood samples obtained on admission and 24 h later (Stratus II immunoassay analyser, Dade International). Levels above 0.5 ng/ml were considered positive. The following data were recorded prospectively: clinical symptoms, co-morbidities, cause of the exacerbation, diagnostic procedures and treatment, general severity score (SAPS II) and in-hospital outcome. CTnI was positive in 18% of patients (95% confidence interval (CI(95)), 11-29%), with a median value at 1.00 ng/ml; CI(95 )(0.60-1.70). Eighteen patients died in the hospital (25%; CI(95), 17-37%). Only cTnI (adjusted odds ratio (ORa), 6.52; CI(95),1.23-34.47) and SAPS II 24 h after admission (ORa, 1.07; CI(95), 1.01-1.13) were independent predictors of in-hospital mortality. CONCLUSION: Elevated cTnI is a strong and independent predictor of in-hospital death in patients admitted for acutely exacerbated COPD.

Aged↗