CT-Assessment of Dependent Lung Densities in Man during General Anaesthesia

Lundquist, H.; Hedenstierna, Göran; Strandberg, Anna K.; Tokics, L.; Brismar, B.

doi:10.1177/028418519503600464

Cited by 184 publications

(71 citation statements)

References 8 publications

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“…The supine position itself reduces FRC by a mean of 0.8 l compared with the upright position [17]. Although we did not observe lung collapse in awake, supine subjects in our previous studies [18], this occurred in one patient in the present investigation. Elderly patients in the present study may be more apt to develop lung collapse in the supine position, airway closure becoming more prominent with age [19].…”

Section: Discussioncontrasting

confidence: 59%

Lung aeration and pulmonary gas exchange during lumbar epidural anaesthesia and in the lithotomy position in elderly patients

et al. 1998

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SummaryWe investigated a total of 36 subjects with a mean (SD) age of 65 (13) years, during baseline conditions (supine, before any anaesthesia), and then during one of the following protocols: (1) lithotomy positioning (n ¼ 12), (2) epidural anaesthesia (n ¼ 12), (3) general anaesthesia in the supine position (n ¼ 12). Lung aeration, ventilation/perfusion matching, gas exchange and functional residual capacity were measured. Lung aeration was normal during baseline assessment with almost no regions with poor aeration and no substantial dependent densities. Shunt and perfusion of poorly ventilated regions were minor. Lithotomy positioning did not reduce functional residual capacity and did not affect aeration of the lung or ventilation/perfusion matching. Epidural anaesthesia, in general, had no effect on aeration, ventilation/perfusion matching or gas exchange, regardless of whether the patient was in the supine or lithotomy position. General anaesthesia, however, caused significant increases in poorly aerated lung regions and in dependent densities (interpreted as atelectasis). In conclusion, no or little impairment of lung aeration and ventilation/perfusion matching was caused by the lithotomy position and/or epidural anaesthesia, contrary to the effects seen during general anaesthesia. However, our findings also suggest that being overweight is a factor that may cause impairment of lung aeration.

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Section: Discussioncontrasting

confidence: 59%

Lung aeration and pulmonary gas exchange during lumbar epidural anaesthesia and in the lithotomy position in elderly patients

et al. 1998

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“…Half of this increase is due to the increase in the oxygen concentration in the functional residual capacity (FRC). During general anaesthesia, up to 85-90% of patients develop atelectasis in dependent lung regions within 5 min of induction [3]. Atelectasis results in a decrease in FRC and a reduction in the oxygen stored in the body.…”

Section: Discussionmentioning

confidence: 99%

“…Induction of general anaesthesia causes an increase in intrapulmonary shunt [1], which is mainly caused by atelectasis formation [2]. Atelectasis appears within minutes of induction of anaesthesia in the lungs of 85-90% of healthy, non-obese patients [3,4].…”

mentioning

confidence: 99%

The effect of positive airway pressure during pre‐oxygenation and induction of anaesthesia upon duration of non‐hypoxic apnoea

Herriger

Frascarolo²,

Spahn

et al. 2004

Anaesthesia

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SummaryPositive end-expiratory pressure (PEEP) applied during induction of anaesthesia may prevent atelectasis formation in the lungs. This may increase the duration of non-hypoxic apnoea by increasing the functional residual capacity. We studied the benefit of PEEP applied during the induction of anaesthesia on the duration of apnoea until the SpO 2 reached 90%. Forty ASA I-II patients were randomly allocated to one of two groups. In the PEEP group (n = 20) patients were pre-oxygenated using 100% O 2 administered using a CPAP device (6 cmH 2 O) for 5 min. Following induction of anaesthesia, patients were mechanically ventilated (PEEP 6 cm H 2 O) for a further 5 min. In the ZEEP group (n = 20), no CPAP or PEEP was used. The duration of apnoea until SpO 2 reached 90% was measured. Non-hypoxic apnoea duration was longer in the PEEP group compared to ZEEP group (599 ± 135 s vs. 470 ± 150 s, p = 0.007). We conclude that the application of positive airway pressure during induction of anaesthesia in adults prolongs the non-hypoxic apnoea duration by > 2 min.

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“…For example, pulmonary inflammation has been shown to occur in nearly all mechanically ventilated patients, although the degree of inflammation can be influenced by ventilator settings and anesthetic type 192021. Atelectasis is also common, occurring in up to 90% of patients 22. The incidence of PPCs has been described as anywhere between 2% and 39% for major non-cardiothoracic surgery and 14-59% for thoracic surgery 2323.…”

Section: Perioperative Lung Injurymentioning

confidence: 99%

Perioperative lung protective ventilation

O’Gara

Talmor

2018

BMJ

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Perioperative lung injury is a major source of postoperative morbidity, excess healthcare use, and avoidable mortality. Many potential inciting factors can lead to this condition, including intraoperative ventilator induced lung injury. Questions exist as to whether protective ventilation strategies used in the intensive care unit for patients with acute respiratory distress syndrome are equally beneficial for surgical patients, most of whom do not present with any pre-existing lung pathology. Studied both individually and in combination as a package of intraoperative lung protective ventilation, the use of low tidal volumes, moderate positive end expiratory pressure, and recruitment maneuvers have been shown to improve oxygenation and pulmonary physiology and to reduce postoperative pulmonary complications in at risk patient groups. Further work is needed to define the potential contributions of alternative ventilator strategies, limiting excessive intraoperative oxygen supplementation, use of non-invasive techniques in the postoperative period, and personalized mechanical ventilation. Although the weight of evidence strongly suggests a role for lung protective ventilation in moderate risk patient groups, definitive evidence of its benefit for the general surgical population does not exist. However, given the shift in understanding of what is needed for adequate oxygenation and ventilation under anesthesia, the largely historical arguments against the use of intraoperative lung protective ventilation may soon be outdated, on the basis of its expanding track record of safety and efficacy in multiple settings.

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CT-Assessment of Dependent Lung Densities in Man during General Anaesthesia

Cited by 184 publications

References 8 publications

Lung aeration and pulmonary gas exchange during lumbar epidural anaesthesia and in the lithotomy position in elderly patients

Lung aeration and pulmonary gas exchange during lumbar epidural anaesthesia and in the lithotomy position in elderly patients

The effect of positive airway pressure during pre‐oxygenation and induction of anaesthesia upon duration of non‐hypoxic apnoea

Perioperative lung protective ventilation

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