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1.
Sleep Disord ; 2016: 7057282, 2016.
Article in English | MEDLINE | ID: mdl-27242930

ABSTRACT

Objective. The most effective nonpharmacological treatment for insomnia disorder is cognitive behavioural therapy-insomnia (CBT-i). However CBT-i may not suit everyone. Auricular acupuncture (AA) is a complementary treatment. Studies show that it may alleviate insomnia symptoms. The aim of this randomised controlled study was to compare treatment effects of AA with CBT-i and evaluate symptoms of insomnia severity, anxiety, and depression. Method. Fifty-nine participants, mean age 60.5 years (SD 9.4), with insomnia disorder were randomised to group treatment with AA or CBT-i. Self-report questionnaires, the Insomnia Severity Index (ISI), Dysfunctional Beliefs and Attitudes about Sleep scale (DBAS-16), Epworth Sleepiness Scale (ESS), and Hospital Anxiety and Depression scale (HAD), were collected at baseline, after treatment, and at 6-month follow-up. A series of linear mixed models were performed to examine treatment effect over time between and within the groups. Results. Significant between-group improvements were seen in favour of CBT-i in ISI after treatment and at the 6-month follow-up and in DBAS-16 after treatment. Both groups showed significant within-group postintervention improvements in ISI, and these changes were maintained six months later. The CBT-i group also showed a significant reduction in DBAS-16 after treatment and six months later. Conclusions. Compared to CBT-i, AA, as offered in this study, cannot be considered an effective stand-alone treatment for insomnia disorder. The trial is registered with ClinicalTrials.gov NCT01765959.

2.
Spinal Cord ; 47(5): 418-22, 2009 May.
Article in English | MEDLINE | ID: mdl-19002147

ABSTRACT

STUDY DESIGN: A prospective cohort study. OBJECTIVES: To evaluate whether patients with cervical spinal cord injury (CSCI) are able to learn the technique of glossopharyngeal pistoning (breathing) for lung insufflation (GI) and if learned, to evaluate the effects of GI on pulmonary function and chest expansion after 8 weeks. SETTING: Karolinska University Hospital, Stockholm, Sweden. METHODS: Twenty-five patients with CSCI (21 men, four women) with a mean age of 46 years (21-70), from the Stockholm area, were used in this study. The participants performed 10 cycles of GI four times a week, for 8 weeks. Pulmonary function tests made before and after the GI training included vital capacity (VC), expiratory reserve volume (ERV), functional residual capacity (FRC; measured with nitrogen washout), residual volume (RV) and total lung capacity (TLC). Chest expansion was measured before and after training. RESULTS: Five of the twenty-five participants had difficulty in performing GI and were excluded in further analysis. Performing a GI maneuvre increased participants' VC on average by 0.88+/-0.5 l. After 8 weeks of training, the participants had significantly increased their VC 0.23 l, (P<0.001), ERV 0.16 l, (P<0.01), FRC 0.86 l, (P<0.001), RV 0.70 l, (P<0.001) and TLC 0.93 l, (P<0.001). Chest expansion increased at the level of the xiphoid process by 1.2 cm (P<0.001) and at the level of the fourth costae by 0.7 cm (P<0.001). CONCLUSIONS: After using GI for a period of 8 weeks, the participants with CSCI who could perform GI were able to improve pulmonary function and chest expansion.


Subject(s)
Breathing Exercises , Cervical Vertebrae/injuries , Inspiratory Capacity , Lung/physiopathology , Spinal Cord Injuries/complications , Spinal Cord Injuries/rehabilitation , Adult , Aged , Expiratory Reserve Volume , Female , Functional Residual Capacity , Humans , Insufflation , Male , Middle Aged , Prospective Studies , Recovery of Function , Residual Volume , Respiratory Function Tests , Respiratory Mechanics , Spinal Cord Injuries/physiopathology , Sweden , Time Factors , Total Lung Capacity , Vital Capacity , Young Adult
3.
Acta Anaesthesiol Scand ; 52(8): 1086-95, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18840109

ABSTRACT

BACKGROUND: Little has been reported about intensive care of children in Sweden. The aims of this study are to (I) assess the number of admissions, types of diagnoses and length-of-stay (LOS) for all Swedish children admitted to intensive care during the years 1998-2001, and compare paediatric intensive care units (PICUs) with other intensive care units (adult ICUs) (II) assess immediate (ICU) and cumulative 5-year mortality and (III) determine the actual consumption of paediatric intensive care for the defined age group in Sweden. METHODS: Children between 6 months and 16 years of age admitted to intensive care in Sweden were included in a national multicentre, ambidirectional cohort study. In PICUs, data were also collected for infants aged 1-6 months. Survival data were retrieved from the National Files of Registration, 5 years after admission. RESULTS: Eight-thousand sixty-three admissions for a total of 6661 patients were identified, corresponding to an admission rate of 1.59/1000 children per year. Median LOS was 1 day. ICU mortality was 2.1% and cumulative 5-year mortality rate was 5.6%. Forty-four per cent of all admissions were to a PICU. CONCLUSIONS: This study has shown that Sweden has a low immediate ICU mortality, similar in adult ICU and PICU. Patients discharged alive from an ICU had a 20-fold increased mortality risk, compared with a control cohort for the 5-year period. Less than half of the paediatric patients admitted for intensive care in Sweden were cared for in a PICU. Studies are needed to evaluate whether a centralization of paediatric intensive care in Sweden would be beneficial to the paediatric population.


Subject(s)
Critical Care/statistics & numerical data , Intensive Care Units, Pediatric/statistics & numerical data , Adolescent , Age Distribution , Child , Child, Preschool , Humans , Infant , Length of Stay , Seasons , Survival Rate , Sweden , Time Factors , Treatment Outcome
4.
Acta Anaesthesiol Scand ; 50(5): 580-5, 2006 May.
Article in English | MEDLINE | ID: mdl-16643228

ABSTRACT

BACKGROUND: Patients suffering from post-polio syndrome still contribute significantly to the number of patients with chronic respiratory failure requiring home mechanical ventilation (HMV). Many of these patients are treated either with invasive (tracheostomy) or non-invasive (nasal mask) controlled mechanical ventilation i.e. volume-controlled ventilation (VCV). In this group of patients, we have previously shown that bi-level pressure support ventilation (bi-level PSV) decreases the oxygen cost of breathing. The aim of this study was to compare the effect of bi-level PSV, with special regard to the adequacy of ventilation and the oxygen cost of breathing, during the patients' ordinary VCV and spontaneous breathing. METHODS: Eight post-polio patients on nocturnal VCV were investigated. Five of them were tracheostomized and three of them used a nasal mask. Work of breathing was analysed by assessing differences in oxygen consumption (VO2) using indirect calorimetry. Blood gases were obtained regularly to assess adequacy of ventilation. RESULTS: Bi-level PSV decreases the oxygen cost of breathing in post-polio patients with respiratory failure without decreasing ventilation efficiency. Furthermore, PaCO2 decreased significantly using this mode of ventilation (P < 0.05). CONCLUSION: In this study, it was shown that bi-level PSV reduces the oxygen cost of breathing and gave a significant decrease in PaCO2 in PPS patients. These data suggest that bi-level PSV ventilation maintains adequate ventilation in patients who suffer from post-polio syndrome with respiratory failure.


Subject(s)
Postpoliomyelitis Syndrome/therapy , Respiration, Artificial , Respiratory Insufficiency/etiology , Respiratory Insufficiency/therapy , Aged , Blood Gas Analysis , Body Mass Index , Calorimetry, Indirect , Carbon Dioxide/blood , Energy Metabolism , Female , Humans , Male , Middle Aged , Respiratory Function Tests , Respiratory Mechanics/physiology
5.
Acta Anaesthesiol Scand ; 50(4): 399-406, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16548851

ABSTRACT

BACKGROUND: The Respiratory Unit (RU) at Danderyd University Hospital opened in 1982, with the expressed goal of supporting outpatients with long-term tracheostomy. The primary aim of this retrospective study in tracheostomized patients was to compare the need for hospital care in the 2-year period before and after the tracheostomy. METHODS: Data were collected from patient medical records at the RU, from the National Board of Health and Welfare, Sweden and from the Official Statistics of Sweden. The subjects were RU patients in 1982 (Group 1, n = 27) and in 1997 (Group 2, n = 106) with long-term tracheostomy surviving at least 4 years after the tracheostomy. RESULTS: Both groups had few and unchanged needs for hospital care after tracheostomy. They spent > or = 96% of their time out of hospital. In 1997, (group 2) the number of patients, diagnoses and need for home mechanical ventilation had increased. Life expectancy was assessed for patients in Group 1. Data showed that they lived as long as an age-matched and gender-adjusted control cohort. CONCLUSIONS: Long-term tracheostomy may not increase the need for hospital care and does not reduce life expectancy. These clinical observations were made in a setting where patients had regular access to a dedicated outpatient unit.


Subject(s)
Home Care Services, Hospital-Based , Respiration, Artificial , Tracheostomy , Adult , Aged , Data Collection , Female , Follow-Up Studies , Hospitalization , Humans , Life Expectancy , Male , Middle Aged , Survival Rate , Tracheostomy/mortality
6.
Acta Anaesthesiol Scand ; 49(2): 197-202, 2005 Feb.
Article in English | MEDLINE | ID: mdl-15715621

ABSTRACT

BACKGROUND: Today, patients with chronic respiratory failure are commonly treated with non-invasive bi-level positive airway pressure ventilation, supporting spontaneous breathing. However, in conformity with previous clinical routine, many post-polio patients with chronic respiratory failure are still treated with invasive (i.e. via a tracheostomy) controlled mechanical ventilation (CMV). The aim of the study was to investigate the effect of invasive bi-level positive airway pressure ventilation on the work of breathing compared with that during the patients' ordinary CMV and spontaneous breathing without mechanical support. METHODS: Nine post-polio patients on invasive (tracheostomy) nocturnal CMV were investigated. Work of breathing was analysed by assessing differences in oxygen consumption (VO2) using indirect calorimetry. Hereby, the oxygen cost of breathing during the various ventilatory modes could be estimated and related to one another. Data on energy expenditure were also obtained. RESULTS: The oxygen cost of breathing decreased by approximately 15% during bi-level positive airway pressure ventilation compared with CMV and spontaneous breathing. There was no difference between predicted (Harris-Benedict equation) and measured energy expenditure. CONCLUSION: Invasive bi-level positive airway pressure ventilation reduces the oxygen cost of breathing in long-standing tracheostomized post-polio patients, compared with CMV. Furthermore, the Harris-Benedict equation provides a reasonable prediction of energy expenditure in this group of patients.


Subject(s)
Home Care Services , Intermittent Positive-Pressure Ventilation/methods , Oxygen Consumption/physiology , Postpoliomyelitis Syndrome/therapy , Respiration, Artificial/methods , Tracheostomy , Work of Breathing/physiology , Aged , Calorimetry, Indirect/methods , Energy Metabolism/physiology , Female , Humans , Male , Middle Aged , Sweden , Time Factors
7.
Acta Anaesthesiol Scand ; 45(10): 1235-40, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11736676

ABSTRACT

BACKGROUND: Short periods of sustained increase in airway pressures (Press(up)) are believed to re-open lung areas that collapsed upon induction of anaesthesia. Recruitment of alveolar surface is usually assessed in terms of changes in the pressure-volume (PV) curve. The purpose of this study was to analyse PV-curves before and after a Press(up) and to ascertain whether such changes are compatible with the concept of recruitment of lung volume. METHODS: During ketamine anaesthesia, 12 healthy piglets were subjected to a Press(up) with end-expiratory pressure (PEEP) of 12 cmH2O and end-inspiratory pressure of 40 cmH2O. Before and after Press(up), PV-curves were obtained from a slow insufflation of 630 ml at zero PEEP (ZEEP). RESULTS: Compliance was non-linear both before and after Press(up) increasing up to 300 ml and sharply decreasing thereafter. After Press(up), the entire compliance curve was shifted to a higher absolute level. Up to 100 ml and a pressure level corresponding to the lower inflection point on the PV-curve (LIP), compliance was higher before Press(up). No effects on blood gases could be observed. CONCLUSION: If the similar shape of the compliance curve corresponds to a similar chain of re-opening and overdistension events, this would imply that all volume gained by Press(up) is lost within 10 min, without explaining the higher absolute compliance following Press(up). We speculate that a) re-opening of rapidly collapsing small airways determines the initial compliance increase; b) the lower compliance after Press(up) until LIP indicates reduced intratidal re-opening of lung regions; and c) changes in bronchomotor tone induced by Press(up) raise the absolute compliance, with a similar scenario of alveolar and small airway recruitment now taking place but at different degrees of airway stiffness.


Subject(s)
Anesthesia , Lung/physiology , Positive-Pressure Respiration , Pulmonary Gas Exchange , Airway Resistance , Anesthetics, Dissociative , Animals , Female , Hemodynamics , Lung Compliance , Male , Pressure , Prone Position , Respiratory Mechanics , Swine , Tidal Volume
8.
Am J Respir Crit Care Med ; 162(6): 2125-33, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11112126

ABSTRACT

Between the lower and the upper inflection point of a quasistatic pressure-volume (PV) curve, a segment usually appears in which the PV relationship is steep and linear (i.e., compliance is high, with maximal volume change per pressure change, and is constant). Traditionally it is assumed that when positive end-expiratory pressure (PEEP) and tidal volume (V T) are titrated such that the end-inspiratory volume is positioned at this linear segment of the PV curve, compliance is constant over VT during ongoing ventilation. The validity of this assumption was addressed in this study. In 14 surfactant-deficient piglets, PEEP was increased from 3 cm H(2)O to 24 cm H(2)O, and the compliance associated with 10 consecutive volume increments up to full VT was determined with a modified multiple-occlusion method at the different PEEP levels. With PEEP at approximately the lower inflection point, compliance was minimal in most lungs and decreased markedly over VT, indicating overdistension. Compliance both increased and decreased within the same breath at intermediate PEEP levels. It is concluded that a PEEP that results in constant compliance over the full VT range is difficult to find, and cannot be derived from conventional respiratory-mechanical analyses; nor does this PEEP level coincide with maximal gas exchange.


Subject(s)
Lung Compliance/physiology , Positive-Pressure Respiration , Pulmonary Surfactants/deficiency , Tidal Volume/physiology , Animals , Bronchoalveolar Lavage/statistics & numerical data , Female , Male , Positive-Pressure Respiration/statistics & numerical data , Pulmonary Gas Exchange/physiology , Random Allocation , Swine , Time Factors
9.
Br J Anaesth ; 85(4): 577-86, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11064617

ABSTRACT

The lower inflection point (LIP) of the inspiratory limb of a static pressure-volume (PV) loop is assumed to indicate the pressure at which most lung units are recruited. The LIP is determined by a static manoeuvre with a PV-history that is different from the PV-history of the actual ventilation. In nine surfactant-deficient piglets, information to allow setting PEEP and VT was obtained, both from the PV-curve and also during ongoing ventilation from the dynamic compliance relationship. According to LIP, PEEP was set at 20 (95% confidence interval 17-22) cm H2O. Volume-dependent dynamic compliance suggested a PEEP reduction (to 15 (13-18) cm H2O). Pulmonary gas exchange remained satisfactory and this change resulted in reduced mechanical stress on the respiratory system, indirectly indicated by volume-dependent compliance being consistently great during the entire inspiration.


Subject(s)
Positive-Pressure Respiration/methods , Respiratory Insufficiency/therapy , Respiratory Mechanics/physiology , Animals , Bronchoalveolar Lavage , Female , Lung Compliance/physiology , Male , Pulmonary Gas Exchange/physiology , Pulmonary Surfactants/deficiency , Respiratory Insufficiency/physiopathology , Stress, Mechanical , Swine
10.
Ups J Med Sci ; 105(1): 17-29, 2000.
Article in English | MEDLINE | ID: mdl-10893050

ABSTRACT

Ventilation with decelerating inspiratory flow is known to reduce the dead space fraction and to decrease PaCO2. Constant inspiratory flow with an end-inspiratory pause (EIP) is also known to increase the removal of CO2. The aim of the study was to elucidate the effect of the pause/no-flow period while both the pattern and rate of inspiratory flow was unchanged, and when the lung was ventilated with sufficient PEEP to prevent end-expiratory collapse. Surfactant depleted piglets were assigned to decelerating or constant inspiratory flow with 24 breaths per minute (bpm) or 12 bpm, or to constant flow, without and with an end-inspiratory pause of 25%. By adding an EIP the total time without active inspiratory flow of the respiratory cycle was kept unchanged. Gas exchange, airway pressures, functional residual capacity (using sulfurhexafluoride) and haemodynamics (thermo-dye indicator dilution technique) were measured. Irrespective of ventilatory frequency, PaCO2 was lower and serial dead space reduced with decelerating flow, compared with constant inspiratory flow. With an end-inspiratory pause added to constant inspiratory flow, serial dead space was reduced but did not decrease PaCO2. The results of this study corroborate the assumption that total time without active inspiratory flow is important for arterial CO2-tension.


Subject(s)
Carbon Dioxide/blood , Positive-Pressure Respiration , Respiratory Mechanics , Animals , Bronchoalveolar Lavage , Functional Residual Capacity , Partial Pressure , Pulmonary Ventilation , Respiratory Dead Space , Swine
11.
Int J Pediatr Otorhinolaryngol ; 50(1): 31-6, 1999 Oct 15.
Article in English | MEDLINE | ID: mdl-10596884

ABSTRACT

Carbon dioxide laser tonsillotomies were performed on 33 children aged 1-12 years for the relief of obstructive symptoms due to tonsillar hyperplasia. As opposed to conventional tonsillectomy, only the protruding part of each tonsil was removed. A carbon dioxide laser delivering 20 W was used for the excision. Twenty-one children were seen in active short-term follow-up and the records of all the children were checked for possible surgery related events up to 20-33 months after surgery. Laser tonsillotomy was uniformly effective in relieving the obstruction, with good hemostasis. The tonsillar remnants healed completely within 2 weeks. No major adverse events occurred. Post-operative pain appeared slight and easily controlled. There was no gain in operating time compared with conventional tonsillectomy. The laser tonsillotomies were in most cases done in day surgery. No recurrence of obstructive problems was reported up to 20-33 months after surgery. It was concluded that tonsillotomy, using a carbon dixoide laser, is a valid treatment for obstructive symptoms caused by enlarged tonsils, which can be performed with little bleeding and post-operative pain. The improved hemostasis may enable a shift from in-patient to day surgery.


Subject(s)
Carbon Dioxide , Laser Therapy/methods , Palatine Tonsil/surgery , Tonsillectomy/methods , Acetaminophen/therapeutic use , Analgesics/therapeutic use , Child , Child, Preschool , Female , Follow-Up Studies , Humans , Hyperplasia/surgery , Infant , Male , Pain, Postoperative/diagnosis , Pain, Postoperative/drug therapy , Palatine Tonsil/pathology
12.
Int J Pediatr Otorhinolaryngol ; 51(3): 171-6, 1999 Dec 15.
Article in English | MEDLINE | ID: mdl-10628543

ABSTRACT

BACKGROUND: tonsillectomy (TE) is currently the most common treatment for children with snoring and sleep apnea. Many of these children have not had any severe throat infections. To cure such children from their obstructive problems, without influencing the immunological function of the tonsils, tonsillotomy (TT) with CO2-laser was performed in a randomized study comparing it to regular tonsillectomy, with special attention to postoperative pain and symptom recurrence. METHOD: 41 children 3.5-8 years-old were included--21 'TT's' and 20 'TE's'. They were all operated under the same anesthesia and followed the same postoperative scheme for analgesia. A visual analogue scale for pain measurements with faces was used for the first 24 h. After that, each day until pain-free, the parents registered the child's pain on a three graded scale, what the child was able to eat, and the amount of analgesic drugs used. RESULTS: all the children were cured from their breathing obstruction. The mean time used for the surgery was the same and no postoperative bleeding was seen in either group. 'TT children' were pain-free after 5 days and 'TE children' after 8 days. Eight to ten days after surgery, the TT-children had gained weight and the TE children lost weight significantly. The TE group used twice as much analgesic drugs as the TT group during the first postoperative week. The TT group was healed with normal-looking, but small tonsils after 8-10 days; the TE group often still showed edema and crusts. At the one-year follow-up 2/21 among the 'TT-children' snored, but did not require re-surgery. CONCLUSION: tonsillotomy is much less painful than TE and children recover more quickly. Results with respect to breathing obstruction are almost the same for both methods at 1-year follow-up.


Subject(s)
Pain, Postoperative , Palatine Tonsil/surgery , Sleep Apnea, Obstructive/surgery , Tonsillectomy , Child , Child, Preschool , Female , Humans , Laser Therapy/adverse effects , Male , Pain Measurement , Pain, Postoperative/drug therapy , Recurrence
13.
Br J Anaesth ; 83(6): 890-7, 1999 Dec.
Article in English | MEDLINE | ID: mdl-10700789

ABSTRACT

Setting an appropriate positive end-expiratory pressure (PEEP) value is determined by respiratory mechanics, gas exchange and oxygen transport. As these variables may be optimal at different PEEP values, a unique PEEP value may not exist which satisfies both the demands of minimizing mechanical stress and optimizing oxygen transport. In 15 surfactant-deficient piglets, PEEP was increased progressively. Arterial oxygenation and functional residual capacity (FRC) increased, while specific compliance of the respiratory system decreased. Static compliance increased up to a threshold value of PEEP of 8 cm H2O, after which it decreased. This threshold PEEP did not coincide with the lower inflection point of the inspiratory limb of the pressure-volume (PV) loop. Oxygen transport did not correlate with respiratory mechanics or FRC. In the lavage model, the lower inflection point of the PV curve may reflect opening pressure rather than the pressure required to keep the recruited lung open. Recruitment takes place together with a change in the elastic properties of the already open parts of the lung. No single PEEP level is optimal for both oxygen transport and reduction of mechanical stress.


Subject(s)
Lung/physiopathology , Positive-Pressure Respiration/methods , Animals , Bronchoalveolar Lavage , Female , Lung Compliance , Lung Volume Measurements , Male , Oxygen/physiology , Positive-Pressure Respiration/adverse effects , Residual Volume/physiology , Swine
15.
Intensive Care Med ; 22(4): 329-35, 1996 Apr.
Article in English | MEDLINE | ID: mdl-8708171

ABSTRACT

OBJECTIVES: Prolongation of inspiratory time is used to reduce lung injury in mechanical ventilation. The aim of this study was to isolate the effects of inspiratory time on airway pressure, gas exchange, and hemodynamics, while ventilatory frequency, tidal volume, and mean airway pressure were kept constant. DESIGN: Randomized experimental trial. SETTING: Experimental laboratory of a University Department of Anesthesiology and Intensive Care. ANIMALS: Twelve anesthetised piglets. INTERVENTIONS: After lavage the reference setting was pressure-controlled ventilation with a decelerating flow; I:E was 1:1, and PEEP was set to 75% of the inflection point pressure level. The I:E ratios of 1.5:1, 2.3:1, and 4:1 were applied randomly. Under open lung conditions, mean airway pressure was kept constant by reduction of external PEEP. MEASUREMENTS AND RESULTS: Gas exchange, airway pressures, hemodynamics, functional residual capacity (SF6 tracer), and intrathoracic fluid volumes (double indicator dilution) were measured. Compared to the I:E of 1:1, PaCO2 was 8% lower, with I:E 2.3:1 and 4:1 (p < or = 0.01) while PaO2 remained unchanged. The decrease in inspiratory airway pressure with increased inspiratory time was due to the response of the pressure-regulated volume-controlled mode to an increased I:E ratio. Stroke index and right ventricular ejection fraction were depressed at higher I:E ratios (SI by 18% at 2.3:1, 20% at 4:1; RVEF by 10% at 2.3:1, 13% at 4:1; p < or = 0.05). CONCLUSION: Under open lung conditions with an increased I:E ratio, oxygenation remained unaffected while hemodynamics were impaired.


Subject(s)
Hemodynamics/physiology , Positive-Pressure Respiration, Intrinsic/physiopathology , Respiration, Artificial/methods , Respiratory Mechanics , Animals , Functional Residual Capacity/physiology , Pressure , Pulmonary Gas Exchange , Random Allocation , Swine , Time Factors
16.
Anesthesiology ; 84(4): 882-9, 1996 Apr.
Article in English | MEDLINE | ID: mdl-8638843

ABSTRACT

BACKGROUND: Recognition of the potential for ventilator-associated lung injury has renewed the debate on the importance of the inspiratory flow pattern. The aim of this study was to determine whether a ventilatory pattern with decelerating inspiratory flow, with the major part of the tidal volume delivered early, would increase functional residual capacity at unchanged (or even reduced) inspiratory airway pressures and improve gas exchange at different positive end-expiratory pressure levels. METHODS: Surfactant depletion was induced by repeated bronchoalveolar lavage in 13 anesthetized piglets. Decelerating and constant inspiratory flow ventilation was applied at positive end-expiratory pressure levels of 22, 17, 13, 9, and 4 cm H(2)O. Tidal volume, inspiration-to-expiration ratio, and ventilatory frequency were kept constant. Airway pressures, gas exchange, functional residual capacity (using a wash-in/washout method with sulfurhexafluoride), central hemodynamics, and extravascular lung water (using the thermo-dye-indicator dilution technique) were measured. RESULTS: Decelerating inspiratory flow yielded a lower arterial carbon dioxide tension compared to constant flow, that is, it improved alveolar ventilation. There were no differences between the flow patterns regarding end-inspiratory occlusion airway pressure, end-inspiratory lung volume, static compliance, or arterial oxygen tension. No differences were seen in hemodynamics and oxygen delivery. CONCLUSIONS: The decelerating inspiratory flow pattern increased carbon dioxide elimination, without any reduction of inspiratory airway pressure or apparent improvement in arterial oxygen tension. It remains to be established whether these differences are sufficiently pronounced to justify therapeutic consideration.


Subject(s)
Respiration, Artificial/methods , Respiratory Insufficiency/therapy , Acute Disease , Animals , Carbon Dioxide/metabolism , Hemodynamics , Pulmonary Gas Exchange , Respiratory Insufficiency/physiopathology , Swine
17.
Ups J Med Sci ; 101(3): 257-71, 1996.
Article in English | MEDLINE | ID: mdl-9055390

ABSTRACT

Inverse ratio ventilation (IRV) is commonly used in clinical practice. Several studies have used IRV in order to recruit collapsed alveoli. In a randomised trial in twelve surfactant depleted piglets, the lungs were ventilated with sufficient positive end-expiratory pressure (PEEP) to prevent end-expiratory collapse, and the effects of increased inspiration-to-expiration (I:E ratio) were evaluated. Pressure regulated ventilation (with I:E of 1:1, constant tidal volume and decelerating inspiratory flow) was used at 30 breaths per minute (bpm). I:E ratios of 1.5:1, 2.3:1 and 4:1 were applied sequentially. When the I:E ratio was increased, external PEEP had to be reduced in order to keep total PEEP constant. Functional residual capacity, airway pressures, gas exchange, extrathermal volume and hemodynamics were measured. With I:E ratios above 2:1 intrinsic PEEP was generated and with concomitant decrease in cardiac index. PaO2 was not affected, but oxygen delivery was reduced. It is concluded that I:E ratios of 2:1, or above, generate increased intrinsic PEEP with compromised hemodynamics.


Subject(s)
Lung/physiology , Positive-Pressure Respiration , Pulmonary Circulation , Respiration, Artificial , Animals , Hemodynamics , Lung Compliance , Oxygen/blood , Pressure , Pulmonary Gas Exchange , Pulmonary Ventilation , Swine
18.
Intensive Care Med ; 21(4): 310-8, 1995 Apr.
Article in English | MEDLINE | ID: mdl-7650253

ABSTRACT

OBJECTIVES: To study the ability of different ventilatory approaches to keep the lung open. DESIGN: Different ventilatory patterns were applied in surfactant deficient lungs with PEEP set to achieve pre-lavage PaO2. SETTING: Experimental laboratory of a University Department of Anaesthesiology and Intensive Care. ANIMALS: 15 anaesthetised piglets. INTERVENTIONS: One volume-controlled mode (L-IPPV201:1.5) and two pressure-controlled modes at 20 breaths per minute (bpm) and I:E ratios of 2:1 and 1.5:1 (L-PRVC202:1 and L-PRVC201.5:1), and two pressure-controlled modes at 60 bpm and I:E of 1:1 and 1:1.5 (L-PRVC601:1 and L-PRVC601:1.5) were investigated. The pressure-controlled modes were applied using "Pressure-Regulated Volume-Controlled Ventilation" (PRVC). MEASUREMENTS AND RESULTS: Gas exchange, airway pressures, hemodynamics, FRC and intrathoracic fluid volumes were measured. Gas exchange was the same for all modes. FRC was 30% higher with all post-lavage settings. By reducing inspiratory time MPAW decreased from 25 cmH2O by 3 cmH2O with L-PRVC201.5:1 and L-PRVC601:1.5. End-inspiratory airway pressure was 29 cmH2O with L-PRVC201.5:1 and 40 cmH2O with L-IPPV201:1.5, while the other modes displayed intermediate values. End-inspiratory lung volume was 65 ml/kg with L-IPPV201:1.5, but it was reduced to 50 and 49 ml/kg with L-PRVC601:1 and L-PRVC601:1.5. Compliance was 16 and 18 ml/cmH2O with L-PRVC202:1 and L-PRVC201.5:1, while it was lower with L-IPPV201:1.5, L-PRVC601:1 and L-PRVC601:1.5. Oxygen delivery was maintained at pre-lavage level with L-PRVC201.5:1 (657 ml/min.m2), the other modes displayed reduced oxygen delivery compared with pre-lavage. CONCLUSION: Neither the rapid frequency modes nor the low frequency volume-controlled mode kept the surfactant deficient lungs open. Pressure-controlled inverse ratio ventilation (20 bpm) kept the lungs open at reduced end-inspiratory airway pressures and hence reduced risk of barotrauma. Reducing I:E ratio in this latter modality from 2:1 to 1.5:1 further improved oxygen delivery.


Subject(s)
Positive-Pressure Respiration/methods , Respiratory Insufficiency/therapy , Analysis of Variance , Animals , Functional Residual Capacity , High-Frequency Ventilation , Microscopy, Electron, Scanning , Pulmonary Alveoli/diagnostic imaging , Pulmonary Alveoli/physiopathology , Pulmonary Alveoli/ultrastructure , Pulmonary Surfactants/deficiency , Radiography , Respiratory Function Tests , Swine
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