0527 The Uptake of a Free Digital CBTi Programme in a Large Commercial Organisation

Introduction

CBTi is effective in the treatment of insomnia and is now recommended as the first-line treatment. However, despite the desirability of CBTi, access to therapy is restricted due to the lack of sufficient appropriately trained and experienced therapists. Because of the lack of therapists and the financial and time costs associated with face to face therapy a number of programmes that offer CBTi digitally have been developed, which have been shown to have similar success rates to receiving therapy in person.

Methods

The uptake of Sleepstation www.sleepstation.org.uk, a clinically proven CBTi platform with additional human support, was investigated when it was offered free to the members of a large organisation in the UK. The availability of the programme was promoted via the organisation’s website for 3 months.

Results

1173 people registered an interest in the programme of which 880 were assessed for suitability (73% female, median age 45yrs). 411 where offered treatment due to symptoms indicative of insomnia. 188 initiated treatment. 137 complete the programme or reached recovery. 112 showed an improvement in their sleep.

Conclusion

Simply reporting the success rate of CBTi only tells part of the story. Simply improving access to CBTi, whether face to face or digitally, does not necessarily improve the initiation, retention, and completion of CBTi therapy. Further research is needed to fully understand the real and perceived barriers to the use of CBTi.

Support

This study was facilitated by Sleepstation

0508 Transcranial Magnetic Stimulation Shows Favorable Response for Insomnia in Depression with Greater Response in Males and in Those Less Than 65 Years of Age

Introduction

Transcranial Magnetic Stimulation (TMS) is FDA approved for the treatment of resistant depression and multiple studies have demonstrated improvement of insomnia in both those with and without depression.

Methods

50 patients were studied while undergoing TMS treatment for resistant depression and utilizing the Patient Health Questionnaire-9 (PHQ-9), the Beck Depression Inventory (BDI), the Insomnia Severity Index (ISI), and the Pittsburgh Sleep Quality Index (PSQI) for evaluation of benefit. Using the Brainsway dTMS system over the LDPFC at 120% MT for an average of 31 treatments, our study demonstrated benefit for both mood and insomnia. We observed an improvement on the PHQ-9 from 17.3 to 7.53, on the BDI from 30.44 to 11.75, on the ISI from 13.47 to 9.31, and on the PSQI from 11.78 to 9.08. Focusing specifically on the insomnia response, we compared an equal number of both male versus female patients, and those > and < than 65 years of age.

Results

Using paired t-test comparisons, men and those less than 65 demonstrated statistically significant improvement. The male population demonstrated statistically significant decreases of t=2.39, 13df, P=.03 on the ISI, and t=2.59, 13df, P=.02 on the PSQI. For women the result was t=1.35, 13df, P=.20 on the ISI, and t=2.05, 13df, P=.06 on the PSQI. In the elderly (>65) decreases were not statistically significant at t=.62, 14df, P=.54 on the ISI, and t=1.26, 14df, P=.23 on the PSQI. For those < 65 years old statistically significant decreases observed were t=3.37, 14df, P=.005 on the ISI, and t=3.5, 14df, P=.004 on the PSQI.

Conclusion

TMS treatment of depression resulted in statistically significant benefits on co-existing insomnia in males and those less than 65 years of age. As insomnia may be a precipitating or perpetuating factor in depression and may result in depression relapse, attention to this symptom is of clinical benefit.

Support

**No support was given for this study. Dr. Stultz is a speaker for Harmony Biosciences and has served on their advisory committee. She is also a speaker for Jazz Pharmaceuticals. She is the co-editor for the Clinical TMS Society Newsletter and on the education committee.

0756 A One Year Observational Early Access Pitolisant Study of Excessive Daytime Sleepiness in Narcolepsy

Introduction

Pitolisant is a H3 receptor antagonist/inverse agonist that has been FDA approved for excessive daytime sleepiness in narcolepsy at doses of either 17.8 mg or 35.6 mg per day.

Methods

13 patients (3 males and 10 females) were studied having an average age of 46.8 years, with the majority receiving a dose of 35.6 mg Pitolisant. One patient received 17.8 mg throughout the year, and another advanced after 6 months to the 35.6 mg dose due to hepatic issues. 12 of the patients were Caucasian and one was Asian. 100% of the patients had co-existing sleep and psychiatric disorders. 46% had co-existing sleep apnea and were on CPAP/BIPAP. 38.5% had a history of a head injury. 84.6% of the patients had associated cataplexy, 38% had sleep paralysis, 92% had disrupted nocturnal sleep, and 46% had hypnogogic hallucinations. Throughout the year the patients were monitored using the Epworth Sleepiness Scale (ESS). Nine patients completed the 12-month ESS scales. 12/13 were on other medications to treat narcolepsy prior to starting Pitolisant. 6/13 were on sodium oxybate, 7/13 were on an antidepressant, and 11/13 were on either a stimulant, modafanil, or armodafanil. Only one patient was on Pitolisant alone.

Results

The patient’s average ESS score at onset was 16.2 Statistically significant findings using paired t-tests were documented. After one-month ESS scores decreased to an average of 13.2 (t=2.38, 9df, P=.04). At 3 months it was 12.4 (t=2.81, 10df, P=.02), at 6 months it was 12.75 (t=4.69, 11df, P<.001) and at 12 months the average score was 13.11 (t=2.55, 8df, P=.03) documenting clinically meaningful decrease of ESS by >/= 3 points. Three patients had ESS scores </=10 at 12 months.

Conclusion

Improvement on ESS was documented at one month and sustained for one year in patients diagnosed with having narcolepsy both with and without cataplexy.

Support

**No support was given for this study. Dr. Stultz is a speaker for Harmony Biosciences and has served on their advisory committee. She is also a speaker for Jazz Pharmaceuticals.

Systemic Immunologic Consequences of Chronic Periodontitis

Chronic periodontitis (ChP) is a prevalent inflammatory disease affecting 46% of the US population. ChP produces a profound local inflammatory response to dysbiotic oral microbiota that leads to destruction of alveolar bone and tooth loss. ChP is also associated with systemic illnesses, including cardiovascular diseases, malignancies, and adverse pregnancy outcomes. However, the mechanisms underlying these adverse health outcomes are poorly understood. In this prospective cohort study, we used a highly multiplex mass cytometry immunoassay to perform an in-depth analysis of the systemic consequences of ChP in patients before (n = 28) and after (n = 16) periodontal treatment. A high-dimensional analysis of intracellular signaling networks revealed immune system-wide dysfunctions differentiating patients with ChP from healthy controls. Notably, we observed exaggerated proinflammatory responses to Porphyromonas gingivalis-derived lipopolysaccharide in circulating neutrophils and monocytes from patients with ChP. Simultaneously, natural killer cell responses to inflammatory cytokines were attenuated. Importantly, the immune alterations associated with ChP were no longer detectable 3 wk after periodontal treatment. Our findings demarcate systemic and cell-specific immune dysfunctions in patients with ChP, which can be temporarily reversed by the local treatment of ChP. Future studies in larger cohorts are needed to test the boundaries of generalizability of our results.

Crystal structure of 2-amino-pyridinium 6-chloro-nicotinate

In the title salt, C5H7N(+)·C6H3ClNO(-), the 2-amino-pyri-din-ium cation inter-acts with the carboxyl-ate group of the 6-chloro-nicotinate anion through a pair of independent N-H⋯O hydrogen bonds, forming an R 2 (2)(8) ring motif. In the crystal, these dimeric units are connected further via N-H⋯O hydrogen bonds, forming chains along [001]. In addition, weak C-H⋯N and C-H⋯O hydrogen bonds, together with weak π-π inter-actions, with centroid-centroid distances of 3.6560 (5) and 3.6295 (5) Å, connect the chains, forming a two-dimensional network parallel to (100).

Enhanced slow wave sleep and improved sleep maintenance after gaboxadol administration during seven nights of exposure to a traffic noise model of transient insomnia

Slow wave sleep (SWS) has been reported to correlate with sleep maintenance, but whether pharmacological enhancement of SWS also leads to improved sleep maintenance is not known. Here we evaluate the time-course of the effects of gaboxadol, an extra-synaptic gamma-aminobutyric acid (GABA) agonist, on SWS, sleep maintenance, and other sleep measures in a traffic noise model of transient insomnia. After a placebo run-in, 101 healthy subjects (20-78 y) were randomized to gaboxadol (n = 50; 15 mg in subjects <65 y and 10 mg in subjects ≥65 y) or placebo (n = 51) for 7 nights (N1-N7). The model caused some disruption of sleep initiation and maintenance, with greatest effects on N1. Compared with placebo, gaboxadol increased SWS and slow wave activity throughout N1 to N7 (p < 0.05). Gaboxadol reduced latency to persistent sleep overall (N1-N7) by 4.5 min and on N1 by 11 min (both p < 0.05). Gaboxadol increased total sleep time (TST) overall by 16 min (p < 0.001) and on N1 by 38 min (p < 0.0001). Under gaboxadol, wakefulness after sleep onset was reduced by 11 min overall (p < 0.01) and by 29 min on N1 (p < 0.0001), and poly-somnographic awakenings were reduced on N1 (p < 0.05). Gaboxadol reduced self-reported sleep onset latency overall and on N1 (both p < 0.05) and increased self-reported TST overall (p < 0.05) and on N1 (p < 0.01). Subjective sleep quality improved overall (p < 0.01) and on N1 (p < 0.0001). Increases in SWS correlated with objective and subjective measures of sleep maintenance and subjective sleep quality under placebo and gaboxadol (p < 0.05). Gaboxadol enhanced SWS and reduced the disruptive effects of noise on sleep initiation and maintenance.

Thinking beyond the bladder: antidiuretic treatment of nocturia

Nocturia is a bothersome and highly prevalent urological condition characterised by the need to wake to void at night. Contrary to popular misconception, nocturia is equally common in men and women, and although its prevalence increases with age, a significant proportion of younger people are also affected. Nocturia leads to repeated fragmentation of sleep and consequently to a serious decline in daytime functioning and in overall quality of life and health. As such, its impact should not be underestimated by clinicians. Traditionally, nocturia has been regarded as a symptom of benign prostatic enlargement and/or overactive bladder syndrome, with treatment therefore directed towards increasing the capacity of the bladder to hold urine. Such treatments have proven largely ineffective in many patients, likely because nocturnal polyuria (NP), a condition that results in overproduction of urine at night, has been found to be present in the majority of nocturia patients. As such, the traditional belief that nocturia is attributable to some other underlying pathological factors, is now being replaced by the acknowledgment that it can be a distinct clinical entity with specific pathogenesis. Frequency-volume charts are an invaluable tool, recommended for routine use in clinical practice, to determine whether nocturia is a result of excessive urine production at night, or of small voided volumes (indicating bladder storage problems), or indeed a combination of these factors. Given the specific antidiuretic action of desmopressin, a synthetic analogue of the body's own antidiuretic hormone, it should be considered as first-line therapy for patients with nocturia where NP is present.

The Mental Capacity Act 2005: implications for dietetic practice

The Mental Capacity Act (MCA) 2005 will be implemented in England and Wales in 2007 and have consequences for dietitians who work with people who may lack capacity to make specific decisions. This paper will explore issues arising from the introduction of the Act and considers the implications for dietitians involved in the delivery of clinical care, using enteral feeding as an illustrative example. If patients lack capacity to make specific decisions, dietitians will be required to record if, how and why they reached a decision, how they are involved in the decision making process and need to be able to justify their actions in relation to those decisions. This paper discusses the importance of dietitians' involvement in best interests decision making and considers the implications of decision making where people have drawn up a Lasting Power of Attorney. The role of such advance decisions is discussed and consideration is given to the potential compatibility of perspectives between the patient and family that may give rise to disputes. Dietitians may be well placed within multidisciplinary team working to ensure patients and their carers are part of the decision making process through effective communication and support for patients. Dietitians in England and Wales must consider the implications of the MCA upon their clinical practice and others outside these jurisdictions may like to reflect on the relevance of such developments in their own contexts.

The effects of co-administration of 3,4-methylenedioxymethamphetamine (“ecstasy”) or para-methoxyamphetamine and moclobemide at elevated ambient temperatures on striatal 5-HT, body temperature and behavior in rats

We have recently demonstrated that co-administration of 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") with the reversible monoamine oxidase type A (MAO-A) inhibitor moclobemide at an ambient temperature of 22 degrees C significantly increases striatal 5-HT outflow and 5-HT-mediated behaviors. In the present study, using microdialysis, we examined the effects of co-administration of MDMA or para-methoxyamphetamine (PMA) with moclobemide on striatal 5-HT outflow at the elevated ambient temperatures of 30 degrees C. Samples were collected every 30 min for 4 h and analyzed by high-performance liquid chromatography assay with electrochemical detection (HPLC-ED). 5-HT-mediated effects on body temperature and behavior were also recorded. Rats were treated with either saline or 20 mg/kg (i.p.) moclobemide, followed by 10 mg/kg (i.p.) MDMA, 10 mg/kg (i.p.) PMA or saline 60 min later. Both MDMA and PMA produced significant increases in 5-HT outflow (370% peak and 309% peak, respectively, P<0.05). MDMA and PMA significantly increased body temperature (+2.0 degrees C and +2.1 degrees C, respectively, P<0.01) and drug-related behaviors (P<0.05). When MDMA or PMA was co-administered with moclobemide, additional significant increases were seen in 5-HT outflow (850% peak, P<0.01 and 1450% peak, P<0.001, respectively) and only MDMA showed additional significant increase in body temperature (+5.0 degrees C, P<0.001). No additional increases were seen in behavioral activity. When moclobemide was co-administered with MDMA, sustained increases in body temperature were recorded that were significantly higher than with MDMA alone and such increases were not observed in our previous study at normal room temperature. Our results suggest greater risk of MDMA-induced adverse effects on body temperature regulation, compared with PMA, when used in combination with moclobemide at elevated ambient temperatures.

Investigating couples' sleep: an evaluation of actigraphic analysis techniques

'Blip' analysis, fast wavelet transformations (FWT) and correlation analysis have all been used to actigraphically assess the impact one person is having on another's sleep, yet no review exists as to the differences between, and applicability of, these methods for investigating couples' sleep. Using actigraphy data and audio sleep diaries collected from 18 couples, this paper provides such a review. This paper constructs and assesses two novel, analytical methods: Lotjonen's sleep/wake algorithm, and the partner impact on sleep wake analysis (PISWA). Both 'blip' analysis and correlation suggest that the strongest relationship between bed partners occurs on an epoch-to-epoch basis. However, 'blips' deal strictly with onset of movement and fail to incorporate strength and duration of movement. Conversely, correlation analysis incorporates some elements of strength and duration of movement but makes identification of onset problematic. FWT offer useful 'relativistic' pattern recognition, identifying onset, strength and duration of movement, but are difficult to quantify. Although audio diary data support the potential of Lotjonen's sleep/wake algorithm to identify sleep non-movement, sleep movement, wake non-movement (or quiet wakefulness) and wake movement, the problem remains that this method also relies on visualization. Of most promise, we argue, is the PISWA, which examines 'impact' of bed partners through incorporating elements of 'blip' analysis and the sleep/wake algorithm.

Effects of fluoxetine and dothiepin on 24-hour activity in depressed patients

Psychomotor retardation is a recognised symptom of depressive illness, and improvement in psychomotor function is associated with the amelioration of the severity of depressive symptoms. Actigraphy permits behavioural activity to be continuously assessed, allowing changes in psychomotor activity to be monitored over time. A randomised, parallel-group, double-blind study was conducted in 14 general practice patients with a diagnosis of major depression. This pilot study was designed to investigate the utility of actigraphy in this patient population and to investigate possible differences between fluoxetine and dothiepin in their effects on 24-hour behavioural activity monitored for the first 10 days of treatment. Patients taking dothiepin (75 mg rising to 150 mg in the second week, nocte) were found to be significantly (p < 0.05) less active over the course of the day compared to those treated with fluoxetine (20 mg, mane). This lower level of behavioural activity in the dothiepin group was particularly noticeable in the early morning (06:00-08:00 h).

Student approaches: supporting students in A&E settings

Nurses working in accident and emergency (A&E) departments near to Higher Education Institutions will be familiar with students attending as the result of sports injuries, and as the consequence of a range of accidents stemming from over-enthusiastic socializing. However, a number of students arrive at A&E departments in distress as the result of mental health problems. This article reports the findings of a small research project exploring mechanisms and support systems for assisting students with mental health needs. It briefly outlines the research and its findings and then considers three relevant issues for those working in A&E: student profiles, student support and the position of students who are considering or engaged in professional education. The article ends with a brief discussion of the position of students undertaking placements within A&E departments.

A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality

RATIONALE

The effects of caffeine, especially caffeinated coffee, on human performance have been extensively studied. However, few studies have been naturalistic representations of how tea/coffee is normally consumed in terms of dose and time of consumption.

OBJECTIVES

This study investigated the effects of day-long consumption of tea, coffee and water on cognitive and psychomotor performance, and sleep quality at night.

METHODS

Thirty healthy volunteers received equal volume drinks equivalent to either 1 or 2 cups of tea (containing 37.5 mg or 75 mg caffeine), or coffee (75 mg or 150 mg caffeine), or water, in a randomised five-way crossover design. Drinks were administered on four occasions during the day (0900, 1300, 1700 and 2300 hours). A psychometric battery consisting of critical flicker fusion (CFF), choice reaction time (CRT) and subjective sedation (LARS) tests, was administered pre-dose and at frequent time points post-dose. The Leeds Sleep Evaluation Questionnaire (LSEQ) was completed each morning and a wrist actigraph was worn for the duration of the study.

RESULTS

Caffeinated beverages maintained CFF threshold over the whole day (P<0.05), independent of caffeine dose or beverage type. During the acute phase of beverage ingestion, caffeine significantly sustained performance compared to water after the first beverage for CFF and subjective sedation (P<0.05), and after the second beverage for the Recognition component of the CRT task (P<0.05). Additionally, there were significant differences between tea and coffee at 75 mg caffeine after the first drink. Compared to coffee, tea produced a significant increase in CFF threshold between 30 and 90 min post-consumption (P<0.01). However, following the second beverage caffeinated coffee at 75 mg significantly improved reaction time (P<0.05), compared to tea at the same dose, for the Recognition component of the CRT task. Caffeinated beverages had a dose dependent negative effect on sleep onset (P<0.001), sleep time (P<0.001) and sleep quality (P<0.001).

CONCLUSIONS

These results indicate that ingestion of caffeinated beverages may maintain aspects of cognitive and psychomotor performance throughout the day and evening when caffeinated beverages are administered repeatedly. This study also demonstrates that day-long tea consumption produces similar alerting effects to coffee, despite lower caffeine levels, but is less likely to disrupt sleep. Other differences between tea and coffee were more subtle, and require further investigation.

Pharmacodynamics of milnacipran in young and elderly volunteers

AIMS

To investigate the pharmacodynamics of milnacipran in healthy young and elderly volunteers.

METHODS

Randomized double-blind crossover designs were employed and a standardized psychometric battery was administered pre and post dose for both studies. In the first study 10 healthy young volunteers received milnacipran 12.5 mg, 25 mg, 50 mg, 100 mg as a single dose or matched placebo. The test battery was administered at baseline and at 1, 2, 4 and 6 h post dose. The second study compared the effects of milnacipran 75 mg (50 mg+25 mg) per day, amitriptyline 50 mg (25 mg+25 mg) per day and placebo for 3 days' dosing in healthy volunteers aged over 65 years. The test battery was administered at baseline and at 2, 10 and 24 h post dose. The psychometric battery included critical flicker fusion (CFF), choice reaction time (CRT), compensatory tracking (CTT) and tests of short-term memory (STM), subjective sedation (LARS) and subjective sleep (LSEQ).

RESULTS

Milnacipran produced no significant dose related effects in the young volunteers. For the elderly, milnacipran significantly (P<0.05) raised CFF scores compared with placebo but had no significant effects on any of the other measures used. Amitriptyline, in contrast, significantly (P<0. 05) lowered CFF threshold, lengthened CRT and increased error on the CTT. On the subjective variables, LARS and LSEQ, amitriptyline increased ratings both of sedation and of difficulty in waking from sleep.

CONCLUSIONS

The results showed that milnacipran at single doses of up to 100 mg in healthy young volunteers is free from disruptive effects on cognitive function and psychomotor performance. In addition, milnacipran 75 mg (50+25 mg) appears to be free of negative effects on cognitive function in elderly volunteers, where it seemingly improves performance on CFF. In contrast, the tricyclic antidepressant amitriptyline, used here as a positive internal control, significantly impaired performance in the elderly on the majority of psychometric measures used in this study. This finding not only validated the sensitivity of this current test battery but also indicates the potential behavioural toxicity of amitriptyline in clinical use in the elderly.

A double-blind, placebo-controlled investigation of the effects of fexofenadine, loratadine and promethazine on cognitive and psychomotor function

AIMS

To assess whether fexofenadine in a range of doses from 80 to 180 mg has any disruptive effects on aspects of psychomotor and cognitive function in comparison with placebo, loratadine and promethazine, an antihistamine known to produce psychomotor and cognitive impairment.

METHODS

Twenty-four healthy volunteers received fexofenadine 80 mg, 120 mg and 180 mg, loratadine 10 mg, promethazine 30 mg (as a positive internal control) and placebo in a six-way crossover, double-blind study. Following each dose, subjects were required to perform a series of tests of cognitive function and psychomotor performance at 1.5, 3, 6, 9, 12 and 24 h post dose. The test battery included critical flicker fusion (CFF), choice reaction time (CRT) and assessment of subjective sedation (LARS). Overall levels of activity were monitored by means of wrist mounted actigraphs throughout each of the 24 h experimental periods.

RESULTS

Fexofenadine at all doses tested was not statistically different from placebo in any of the tests used and loratadine did not cause any significant impairment of cognitive function. Significant impairments were found following promethazine. Promethazine caused a significant reduction in CFF threshold and this effect was evident up to 12 h post dose (P<0.05). There was a significant increase in recognition reaction time at 3 and 6 h post promethazine administration, and the drug caused a significant (P<0. 002) increase in the percentage of 'sleep-like' activity from actigraph records during the daytime.

CONCLUSIONS

Fexofenadine at doses up to 180 mg appears free from disruptive effects on aspects of psychomotor and cognitive function in a study where the psychometric assessments have been shown to be sensitive to impairment, as evidenced by the effects of the verum control promethazine 30 mg.

The effects of cigarette smoking on overnight performance

Fifteen healthy smokers and 15 non-smokers were enrolled into this study investigating the effects of smoking on overnight performance. Subjects arrived at the test centre at 1930 hours and were assessed at baseline (2000 hours) and at 2200, 0000, 0200, 0400, 0600, and 0800 hours on a battery of tests (including Critical Flicker Fusion, CFF; Choice Reaction Time, CRT; Compensatory Tracking Task, CTT; Short Term Memory Task, STM; and the Line Analogue Rating Scale, LARS). Results showed that the performance of the smokers was more consistent with baseline measures than that of the non-smokers, which became more impaired throughout the night on a number of tasks [CFF (P < 0.005), Total Reaction Time (TRT, P < 0.05), CTT (P < 0.05) and the Reaction Time (RT) aspect of the CTT task (P < 0.0005)]. The Recognition Reaction Time (RRT) aspect of the CRT task showed that the performance of the non-smokers became more impaired from baseline (P < 0.005), while that of the smokers remained at baseline levels until 0400 hours, when it deteriorated to become comparable to that of the non-smoking controls. Subjective sedation ratings (LARS) resulted in comparable levels of impairment for both study groups (P < 0.00005). Findings from the STM task failed to reach significance. These data suggest that when performance is being measured overnight, smokers show little or no impairment, whilst the performance of non-smokers showed performance decrements.

Comparison of the effects of astemizole/pseudoephedrine and triprolidine/pseudoephedrine on CNS activity and psychomotor function

The sedative properties of astemizole-D and triprolidine-D were compared in a double-blind, placebo-controlled, repeated-measures design study comprising three experimental treatments, each with a duration of 2 days (n = 12). Sedation was assessed by continuous electroencephalographic measurement (C-EEG), intermittent performance testing and subjective measures. C-EEG monitoring revealed that triprolidine-D produced significantly more daytime sedation and drowsiness than either astemizole-D or placebo (p < 0.05). Intermittent performance testing did not reveal consistent psychomotor deficits. There were no differences from placebo; the only significant findings showed that astemizole-D improved tracking accuracy at T + 65 h (p < 0.05) compared to baseline. Also, when scores were summed across all time points, astemizole-D improved scores significantly in contrast to triprolidine-D for the total scores (p < 0.05). It is concluded that, in contrast to triprolidine-D, astemizole-D does not produce daytime drowsiness or sedation.

Regional lung function in patients with hepatic cirrhosis

The lung volume at which the dependent lung zones begin to trap gas as a result of airway closure (i.e., the "closing volume") was measured with (133)Xe in 10 seated patients with hepatic cirrhosis. In all of them the closing volume was increased above normal, and in eight it was greater than the functional residual capacity, indicating the presence of airway closure and gas trapping during resting tidal volume breathing. Direct measurements made with (133)Xe in five cirrhotic patients (a) confirmed the presence of increased gas trapping in the lower lung zones both at residual volume and at functional residual capacity, and (b) indicated that in liver cirrhosis the ventilation-perfusion ratio of the dependent lung zones may be very low, primarily as a result of decreased ventilation due to airway closure. It is concluded that in hepatic cirrhosis, gas trapping in the dependent lung zones may be an important cause of impaired gas exchange within the lungs. It is suggested that the premature airway closure observed in this disease may be due to mechanical compression of small airways by dilated blood vessels and/or interstitial pulmonary edema.