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PubMed2005

Using a bundle approach to improve ventilator care processes and reduce ventilator-associated pneumonia.

BACKGROUND: A "bundle" of ventilator care processes (peptic ulcer disease prophylaxis, deep vein thrombosis prophylaxis, elevation of the head of the bed, and a sedation vacation), which may also reduce ventilator-associated pneumonia (VAP) rates, can serve as a focus for improvement strategies in intensive care units (ICUs). Between July 2002 and January 2004, teams of critical care clinicians from 61 health care organizations participated in a collaborative on improving care in the ICU. METHODS: ICU team members posted data monthly on a Web-based extranet and submitted narrative descriptions describing the changes tested and the strategies implemented. RESULTS: For the 35 units that consistently collected data on ventilator bundle element adherence and VAP rates, an average 44.5% reduction of VAP was observed. DISCUSSION: The goal-oriented nature of the bundle appears to demand development of the teamwork necessary to improve reliability. The observations seem sufficiently robust to support implementing the ventilator bundles to provide a focus for additional change in ICUs.

Canada↗
PubMed2003

[Ventilation in special situations. Mechanical ventilation during transportation of pediatric patients].

Most severe pediatric injuries occur far from regional centres specialized in the definitive care of the critically-ill child. Adequate initial stabilization and an appropriate transport system significantly decrease morbidity and mortality in these patients. In the last few years, technological developments have improved the quality of medical transportation. Mechanical ventilation is one of the elements that has been affected by these advances with portable ventilators and monitoring systems that are increasingly similar to those used in pediatric intensive care units. To prevent complications from developing during transportation, adequate preparation is required consisting of (i) prior stabilization of the patient, (ii) assessment of potential risks and specific needs, (iii) monitoring, (iv) transport preparation, and (v) assessment of vital signs and patient management. Portable ventilators are designed to be used for short periods under difficult conditions (temperature changes, altitude, rain, knocks, etc.). Consequently they should have specific common characteristics: portability, resistance, ease of handling, low electricity and gas consumption, and safety. They should also be easy to set up. Their programming is generally similar to that of conventional ventilators and should be based on the physiologic characteristics of the child according to age and underlying process.

Child↗
PubMed1998

The effect of circuit compliance on delivered ventilation with use of an adult circle system for time cycled volume controlled ventilation using an infant lung model.

This in vitro study examined the effect of circuit compliance on delivered ventilation (VE) using a time-cycled, volume controlled circle system in an infant lung model. A Bio-Tek ventilator tester set to simulate normal and abnormal lung compliance measured VE delivered by the Narkomed 2B system. Circle circuits of varied compliance (2.75, 1.22 and 0.73 microliters.cm H2O-1) were tested. Tidal volume was adjusted to peak inflation pressures (PIP) of 20, 30, 40, and 50 cm H2O with three circuits, two lung compliances, and four different size tracheal tubes (TT) (2.5, 3.5, 4, 4.5 mm ID). Data were analysed using the multiple regression technique. Delivered VE was directly related to PIP and lung compliance. Delivered VE was not affected by the choice of circuit. TT size had minimal effects on VE when lung compliance was low; TT size was a more important factor when test lung compliance was normal. Extrapolating this data to the clinical setting, adequate ventilation of infants can be achieved with an adult circle system if an appropriate PIP is chosen, regardless of the compliance of the circuit used. Infants with poor lung compliance may require very high PIP for adequate ventilation.

Adult↗
PubMed2002

Occurrence of ventilator-associated pneumonia in mechanically ventilated pediatric intensive care patients during stress ulcer prophylaxis with sucralfate, ranitidine, and omeprazole.

PURPOSE: The purpose of the study was to evaluate the effects of sucralfate, ranitidine, and omeprazole use on incidence of ventilatory-associated pneumonia (VAP) and mortality in ventilated pediatric critical care patients. MATERIALS AND METHODS: This prospective study was conducted at the pediatric intensive care unit (PICU) between August 2000 and February 2002. A total of 160 patients who needed mechanical ventilation were randomized into 4 groups according to the computer-generated random number table: group (S), (n = 38) received sucralfate suspension 60 mg/kg/d in 4 doses via the nasogastric tube that was flushed with 10 mL of sterile water; group (R), (n = 42) received ranitidine 2 mg/kg/d intravenously in 4 doses; group (O), (n = 38) received omeprazole 1 mg/kg/d intravenously in 2 doses; and group (P), (n = 42) did not receive any medication for stress ulcer prophylaxis. Treatment was begun within 6 hours of PICU admission. RESULTS: Seventy patients (44%) developed VAP. VAP rate was 42% (16 of 38) in the sucralfate group, 48% (20 of 42) in the ranitidine group, 45% (17 of 38) in the omeprazole group, and 41% (17 of 42) in the nontreated group. Overall mortality rate was 22% (35 of 160); it was 21% (8 of 38) in the sucralfate group, 23% (10 of 42) in the ranitidine group, 21% (8 of 38) in the omeprazole group, and 21% (9 of 42) in the nontreated group. Our results did not show any difference in the incidence of VAP and mortality in mechanically ventilated PICU patients treated with ranitidine, omeprazole, or sucralfate, or nontreated subjects (P =.963, confidence interval [CI] = 0.958-0.968; P =.988, CI = 0.985-0.991, respectively). Nine patients (5.6%) had macroscopic bleeding. There was no statistically significant difference in macroscopic bleeding between groups. CONCLUSIONS: Our results did not show any difference in the incidence of VAP, macroscopic stress ulcer bleeding, and mortality in the mechanically ventilated PICU patients treated with ranitidine, omeprazole, or sucralfate, or nontreated subjects. None of the treatment regimens increased VAP compared with the nontreated group. Because there is insufficient data about stress ulcer prophylaxis and VAP in the pediatric age group, more studies with larger numbers of patients are needed.

Anti-Ulcer Agents↗
PubMed2004

[A comparison of the effects of 50 % oxygen combined with CPAP to the non-ventilated lung vs. 100 % oxygen on oxygenation during one-lung ventilation].

OBJECTIVE: In a prospective, randomised, double-blind study the effects of FiO (2) of 0,5 with CPAP and a FiO (2) of 1.0 without CPAP on oxygenation and pulmonary shunt during one-lung ventilation (OLV) were examined. METHODS: In 20 patients undergoing thoracotomy (ASA II/III) two sequential ventilation methods were used during OLV: a) FiO (2) of 1.0 (OLV-100) and b) a FiO (2) of 0.5 in N (2)O combined with CPAP of 5 cm H (2)O to the non-ventilated lung (OLV-CPAP), whereby the sequence in 10 patients was OLV-CPAP followed by OLV-100; and the opposite in the remaining 10 patients. Operating conditions were graded by the surgeon. RESULTS: OLV-CPAP was associated with a better oxygenation and a lower shunt compared to OLV-100 (paO (2) : 198 +/- 40 mmHg vs 181 +/- 38 mmHg; p < 0.05 and Qs/Qt: 30 +/- 6 % vs. 34 +/- 8 %; p < 0.01, respectively). The different sequence of the ventilation methods did not cause significant differences in the results. The surgical conditions were not impaired by the CPAP of 5 cm H (2)O. CONCLUSION: The application of low FiO (2) with CPAP provided a better oxygenation and a lower pulmonary shunt during the OLV compared to high FiO (2) without CPAP.

Aged↗
PubMed1983

CO2-H+ stimuli and neural muscular drive to ventilation during dynamic exercise: comparison of stimuli at constant levels of ventilation.

In exercising man, the ventilatory responses to CO2-H+ stimuli and neural muscular drives were compared at constant ventilation (VE). For that purpose, a small increase of the CO2-H+ stimulus in exercise was to be counterbalanced by work load reductions in such a way that the magnitude of ventilation remained unchanged. Control of end-tidal PO2 and PCO2 (PETO2, PETCO2) was established to minimize the influence of changed mixed venous gas tensions on the arterial levels. Only in metabolic acidosis could the additional CO2 stimulus be compensated by work load reduction. This compensation was due to the concomitant decrease of acidosis. Below the 2 mmol X l-1 [La]a threshold, decrements of work load, VO2, and VCO2 showed no effect on VE, when PETCO2 and PETO2 were regulated at constant levels. After the termination of end-tidal clamps, the proportional relation of VE to VO2, VCO2, and work load was largely reestablished. The results show that neural muscular drives cannot decrease ventilation against a background of constant arterial feedback stimuli. Transient decreases of the CO2-H+ stimulus seem to be necessary to readjust the ventilation to a decreased CO2 flow to the lungs. It is suggested that the overall effect of decreasing CO2 is to inhibit the respiratory centers and that positive ventilatory effects of CO2 are the result of a disinhibitory influence.

Acidosis↗
PubMed1978

Intermittent mandatory ventilation during anaesthesia using the Manley Servovent ventilator.

The lungs of 25 patients were ventilated with intermittent mandatory ventilation (IMV) during anaesthesia using the Manley Servovent Model MS. This ventilatory mode is especially suitable for prolonged operations in which there is no need for muscle relaxation. While incorporating the advantages of spontaneous and mechanical ventilation, it is superior to both in selected cases. The Manley Servovent Model MS ventilator is capable of delivering IMV without modification, using a single source of gas.

Adolescent↗
PubMed1983

Manual jet ventilation v. high frequency jet ventilation during laser resection of tracheo-bronchial stenosis.

Manual jet ventilation (20 b.p.m.) and high frequency jet ventilation (300 b.p.m.) were compared during laser resection of tracheo-bronchial stenosis under general anaesthesia. Both methods provided similar blood-gas tensions at the 10th min of surgery in patients with tracheal stenosis. In patients with bronchial stenosis high frequency jet ventilation resulted in modest hypercarbia and manual jet ventilation appeared to be the preferred method in these particular patients.

Anesthesia, General↗
PubMed1983

Ventilation requirements during high frequency ventilation.

This study was undertaken to investigate ventilatory requirements during high frequency ventilation (HFV). Six anesthetized dogs were ventilated with bird M-2 or Emerson 2-V ventilators at respiratory rates (RRs) ranging from 13-1300 breath/min. PaCO2 was maintained within normal range at all rates by tidal volume (VT) adjustment. Required minute volume (VE) increased linearly with rate while VT decreased exponentially and approached a plateau at rates above 200. Airway pressure was inversely proportional to rate at rates below 80 but increased with rate thereafter. A method is provided to estimate required ventilatory volume during HFV based on the results of this study. It was concluded that gas exchange during HFV can be explained by conventional concepts of ventilation and with an unvented nonrebreathing system no benefit accrues from respiratory rates above 200 inasmuch as neither airway pressure nor VT can be reduced in the face of increasing VE requirements.

Animals↗
PubMed1984

Comparison of high-frequency jet ventilation with conventional mechanical ventilation in saline-lavaged rabbits.

A surfactant-depletion lung-injury model was produced in 37 New Zealand white rabbits by saline lavage. During the next 2 to 3 h, rabbits were ventilated with conventional mechanical ventilation (CMV, group 1), high-frequency jet ventilation (HFJV, group 2), or CMV for 1 h followed by HFJV for 2 h (CMV/HFJV, group 3). Survival until planned termination of the protocol was 56%, 77%, and 63% in groups 1, 2 and 3, respectively. Causes of early demise were usually pneumothorax or metabolic acidosis. There were no statistically significant differences among the groups with respect to survival, incidence of pneumothorax or metabolic acidosis. Arterial oxygenation was more efficient with HFJV (group 2) (P[A-a]O2 = 372 +/- 51 torr [mean +/- SE] at 2 h) than with CMV (group 1) (P[A-a]O2 = 512 +/- 18 torr at 2 h, p less than .01). Furthermore, oxygen gas exchange in 3 of 5 group 3 rabbits improved after institution of HFJV. In contrast to previous findings with high-frequency oscillation (HFO), there were no qualitative histologic differences between lungs ventilated with HFJV vs. CMV. Thus, although HFJV produced more efficient gas exchange in this model, it did not improve pulmonary pathology. HFO may be preferable to HFJV in infant respiratory distress syndrome.

Animals↗
PubMed1984

High-frequency jet ventilation for differential lung ventilation.

High-frequency jet ventilation using a jet injector located at the right mainstem bronchus was superimposed on standard mechanical ventilation to ventilate the injured lung of a patient with unilateral massive atelectasis secondary to pulmonary hemorrhage. This technique of differential ventilation markedly improved arterial oxygenation in this patient and may prove to be a simpler modality of respiratory support in patients who have respiratory failure from unilateral lung disease.

Hemorrhage↗
PubMed1991

Measurement of minute ventilation in ventilator-dependent patients: need for standardization.

OBJECTIVES: a) To determine the variation in methods used to measure minute ventilation (VE) in patients who receive mechanical ventilation; b) to determine the effect of supplemental oxygen on VE, respiratory rate (RR), and tidal volume (VT) measurements. DESIGN: Telephone survey of hospitals, and a randomized control trial. SETTING: Medical and surgical ICUs in a university hospital. PATIENTS: Thirty-three patients who had required mechanical ventilation because of the inability to sustain adequate spontaneous ventilation. All patients were considered ready to undergo a weaning trial by their physicians. INTERVENTIONS: Spontaneous VE, RR, VT, and SaO2 were measured both in the presence and absence of supplemental oxygen; measurements were obtained in a randomized manner. MEASUREMENTS AND MAIN RESULTS: a) In a telephone survey of hospitals throughout the country, we found that the measurement of VE is variably obtained during room air breathing or in the presence of supplemental oxygen. b) Measurements of VE increased from 11.0 +/- 0.8 L/min while patients received supplemental oxygen to 13.5 +/- 1.1 L/min while patients breathed room air (p less than .001). Of 15 patients who had a VE less than 10 L/min while receiving supplemental oxygen, seven developed a value greater than 10 L/min while breathing room air; thus, a weaning trial might have been inappropriately deferred in these patients. c) Mean SaO2 decreased from 95.0 +/- 0.6% while breathing supplemental oxygen to 90.2 +/- 1.1% while breathing room air (p less than .001). CONCLUSIONS: Measurements of VE in patients being considered for a weaning trial can result in significant oxygen desaturation if obtained during room air breathing, and the values obtained can significantly overestimate the patient's true ventilatory requirements, since most patients receive supplemental oxygen during a weaning trial. Standardized methods of measuring VE in critically ill patients need to be developed.

Humans↗
PubMed1996

Continuous non-invasive monitoring of energy expenditure, oxygen consumption and alveolar ventilation during controlled ventilation: validation in an oxygen consuming lung model.

BACKGROUND: We have developed a combined indirect calorimetric and breath-by-breath capnographic device (GEM) for respiratory monitoring: oxygen consumption (VO2), carbon dioxide excretion (VCO2), respiratory quotient (RQ), energy expenditure (EE), alveolar ventilation (VA) and dead space/total ventilation (VD/VT). METHODS: The device was tested in a lung model in which VO2 was achieved by combustion of hydrogen. VCO2 was achieved by delivering CO2 into the single alveolus combustion chamber. VO2, VCO2, compliance, and anatomical dead space could be varied independently. RESULTS: Measured VO2 was 101 +/- 3% (SD) of set value at a F1O2 < 0.6 and 101 +/- 7% at a F1O2 > 0.6 during 15 hours of testing. The corresponding VCO2 values were 99 +/- 2% and 102 +/- 7%. The GEM could with good accuracy measure accumulated energy expenditure (EE) during simulated unstable patient conditions up to a F1O2 of 0.8. At F1O2 above 0.8 VCO2 and VO2 could be estimated using a default RQ value of 0.85. On-line estimated VA and VD/VT values could be obtained at any F1O2 up to 1.0. In a test sequence with stable VO2 and VCO2 the GEM adequately followed changes in VA, induced by changes in anatomical dead space, breathing frequency and compliance. CONCLUSION: The overall performance of the device is satisfactory and well comparable with any equipment tested. It allows near-continuous non-invasive monitoring of EE, VO2, VCO2, VA, VD/VT in ventilated, critically ill patients, providing a rationale for ventilator settings and nutritional support.

Capnography↗
PubMed1978

Weaning very low birthweight infants from mechanical ventilation using intermittent mandatory ventilation and theophylline.

Two very low birthweight infants with severe clinical hyaline membrane disease requiring mechanical ventilation were dependent on slow-rate intermittent mandatory ventilation, without which they developed apnoea or hypopnoea and hypercarbia. Their ventilator dependence was apparently owing to inadequate ventilatory effort, and treatment with oral theophylline allowed easy weaning to continuous-positive airway pressure and extubation. PaCO2 was significantly lower during theophylline treatment, suggesting that the drug may have improved alveolar ventilation.

Apnea↗
PubMed1981

Measurement of dead space ventilation using a pHa servo-controlled ventilator.

A control system for the systemic arterial pH (pHa) servo control of mechanical ventilation has recently been developed. If pHa is maintained constant by the change, separation of minute volume into alveolar ventilation and physiological dead space ventilation (VE = fVA VDp) can be manipulated to show that VDp = (VE1 - VE 2)/(f1 - fe) where f1 and f2 are different ventilator frequencies and VE1 and VE2 are expired minute volumes at these frequencies. Also, added dead space can be measured. VDadded = (VE2 - VE1)/f where VE1 and VE2 are the minute volumes before and after the dead space was added. The validity of these equations was tested in the anesthetized dog. The measured added dead space was in close agreement with the volume of dead space which was added and with that measured by another independent method. The measurement of VDp, probably as a result of tidal volume-related changes in VDp, did not agree as well with VDp measured by an independent method.

Animals↗
PubMed1987

A comparison of high-frequency oscillation superimposed onto backup mechanical ventilation and conventional mechanical ventilation on the distribution of exogenous surfactant in premature lambs.

Twenty-six premature lambs were treated by tracheal instillation of [14C]labeled natural sheep surfactant before the onset of breathing or after the establishment of respiratory distress syndrome 30 min after birth. Half of both groups were subsequently ventilated for 3 h with 100% O2 by conventional mechanical ventilation (CMV) and half by high frequency oscillation superimposed onto backup mechanical ventilation (HFOV). Mean airway pressure, arterial blood pressures, and heart rate were recorded continuously. Arterial blood gases and pH were obtained every 15 min. After sacrifice, the distribution of radiolabeled surfactant was quantified and alveolar expansion was evaluated by morphometrics. At comparable oxygenation, mean airway pressures were significantly lower in the lambs treated with surfactant at birth (groups CMV-B and HFOV-B) than in lambs on CMV and treated with surfactant during RDS (group CMV-R). Mean airway pressures in both groups of lambs on HFOV (groups HFOV-B and HFOV-R) were comparable at values lower than in group CMV-R and higher than in group CMV-B. The distribution of radiolabeled surfactant was more homogeneous in lambs treated at birth and not different for both types of ventilatory assistance. Morphometrics demonstrated significantly better expansion of the alveoli of lambs ventilated with HFOV than of those on CMV, irrespective of the timing of surfactant administration. These results indicate that prophylactic surfactant administration at birth leads to a better distribution of surfactant than rescue treatment with surfactant after the establishment of respiratory distress syndrome and is not affected by a subsequent type of ventilatory assistance.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Peritoneal ventilation: an animal model of extrapulmonary ventilation in experimental adult respiratory distress syndrome.

Adult respiratory distress syndrome (ARDS) is a critical medical problem in which severe arterial hypoxemia is often poorly responsive to conventional modes of mechanical ventilation. We studied the efficiency of mechanical ventilation of the peritoneal cavity in rabbits with experimental ARDS caused by lung lavage. The study shows that peritoneal ventilation is significantly effective in oxygenation of hypoxemic animals with ARDS and is also effective for carbon dioxide elimination. Peritoneal ventilation may be considered as an investigational method for extrapulmonary oxygenation in severe intractable hypoxemia caused by ARDS.

Animals↗
PubMed2001

Early activation of inflammation and clotting in the preterm lamb with neonatal RDS: comparison of conventional ventilation and high frequency oscillatory ventilation.

In neonatal respiratory distress syndrome activation of inflammation and clotting is demonstrated. High frequency oscillatory ventilation (HFOV) is considered to be less damaging to the human preterm lung, resulting in less activation of inflammation and clotting compared with conventional ventilation (CV). To assess the sequence of events of activation of inflammation and clotting and to compare the impact of HFOV to CV, we ventilated preterm lambs delivered by cesarean section at 132 d gestational age (term 145 d) for 8 h by CV (n = 10) or HFOV (n = 11). Fifteen minutes after birth and at 2-h intervals thereafter blood samples, from umbilical catheters, were analyzed for AP50 (complement activation), number of polymorphonuclear leukocytes, beta-glucuronidase, platelet function, activated partial thromboplastin time, thrombin time and thrombin inhibition, and bronchoalveolar lavage fluid was analyzed for elastase, thrombin and protein. We found complement activation, low number of polymorphonuclear leukocytes and high levels of beta-glucuronidase already at 15 min after birth. Within 2 to 4 h after birth platelet function deteriorated, activated partial thromboplastin time prolonged, and thrombin inhibition decreased. Activation of inflammation and clotting in the lungs was demonstrated by increased levels of elastase and thrombin in bronchoalveolar lavage fluid. In the HFOV group, AP50 remained significantly higher than in the CV group, reflecting less complement activation, and platelet function analysis remained significantly lower, reflecting better platelet function. We conclude that systemic activation of inflammation can be found in the ventilated preterm lamb with respiratory distress syndrome within 15 min after birth. Afterward, or due to activation of inflammation, clotting is activated. HFOV possibly attenuates activation of inflammation.

Animals↗