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Background: Within a central operating room area, after general anesthesia (GA) patients are at risk of hypoxemia during transport to the postanesthesia care unit (PACU); however, specific risk factors have not been conclusively clarified and uniform recommendations for monitoring vital signs during transport within a central operating room area complex do not exist. The purpose of this retrospective database analysis was to identify risk factors for hypoxemia during this transport and to determine whether the use of transport monitoring (TM) affects the initial value of peripheral venous oxygen saturation (S p O 2 ) in the PACU., Material and Methods: This analysis was performed on a retrospectively extracted dataset of procedures in GA within a central operating room area of a tertiary care hospital from 2015 to 2020. The emergence from GA was conducted in the operating room with subsequent transport to the PACU. The transport distance was between 31 and 72 m. Risk factors for initial hypoxemia in the PACU, defined as peripheral oxygen saturation (S p O 2 ) below 90%, were determined using multivariate analysis. After splitting the dataset into patients without TM (group OM) and with TM (group MM) and propensity score matching, the influence of TM on initial S p O 2 and the Aldrete score after arrival in the PACU were examined., Results and Discussion: From a total of 22,638 complete datasets included in the analysis, 8 risk factors for initial hypoxemia in PACU were identified: age > 65 years, body mass index (BMI) > 30 kg/m 2 , chronic obstructive pulmonary disease (COPD), intraoperative airway driving pressure (∆p) > 15 mbar and positive endexpiratory pressure (PEEP) > 5 mbar, intraoperative administration of a long-acting opioids, first preoperative S p O 2 < 97%, and last S p O 2 < 97% measured after emergence from anesthesia before transport. At least 1 risk factor for postoperative hypoxemia was present in 90% of all patients. After propensity score matching, 3362 datasets per group remained for analysis of the influence of TM. Patients transported with TM revealed a higher S p O 2 at PACU arrival (MM 97% [94; 99%], OM 96% [94; 99%], p < 0.001). In a subgroup analysis, this difference between groups remained in the presence of one or more risk factors (MM 97% [94; 99%], OM 96% [94; 98%], p < 0.001, n = 6044) but was not detectable in the absence of risk factors for hypoxemia (MM 97% [97; 100%], OM 99% [97; 100%], p < 0.393, n = 680). Furthermore, the goal of an Aldrete score > 8 at PACU arrival was achieved significantly more often in monitored patients (MM 2830 [83%], OM: 2665 [81%], p = 0.004). Critical hypoxemia (S p O 2 < 90%) at PACU arrival had an overall low occurrence within propensity matched datasets and showed no difference between groups (MM: 161 [5%], OM 150 [5%], p = 0.755). According to these results, consistent use of TM leads to a higher S p O 2 and Aldrete score at PACU arrival, even after a short transport distance within an operating room area. Consequently, it appears to be reasonable to avoid unmonitored transport after general anesthesia, even for short distances., (© 2023. The Author(s).)

Background: Studies conducted shortly after the implementation of pulse oximetry (PO) into clinical practice 20-25 years ago revealed that many patients breathing room air during transfer from the operating room (OR) to the post-anesthesia care unit (PACU) directly after general anesthesia (GA) had a peripheral oxygen saturation (S(p)O(2)) below 90%. Moreover, it was shown that the detection of hypoxemia by clinical criteria is extremely unreliable. Meanwhile, the use of PO has become part of the obligatory standard monitoring during GA in Germany and many other countries. Likewise, the use of PO is standard care in the PACU although there are no official recommendations. However, for the time period in between, i.e. immediately after GA during transportation of patients from the OR to the PACU, monitoring of the S(p)O(2) in patients breathing room air is neither obligatory in Germany nor are there any official recommendations or guidelines in this respect. Given the introduction of shorter acting anesthetic agents within the last 25 years, the main goal of this study was to explore whether the incidence of hypoxemia in the immediate period after GA is still so high. Additional aims of this study were to examine whether the detection of hypoxemia based on clinical criteria can be confirmed to be very unreliable, what the risk factors for hypoxemia following GA are and how common it is in Germany to transport patients from the OR to the PACU without PO and supplemental oxygen., Methods: In a prospective observational study 970 patients who underwent a broad spectrum of elective surgery under GA in a university hospital setting were included. The S(p)O(2) was measured at the end of the transfer from the OR to the PACU immediately after the anesthetist who had taken care of the patient during the operation had estimated the S(p)O(2). The association between biometric, surgical and anesthesiological variables on the one hand and hypoxemia as well as a decrease of S(p)O(2) on the other hand were studied using multivariate methods. Finally, a survey including all university hospitals was carried out to find out about the use of PO and oxygen during patient transfer from the OR to the PACU., Results: Of the 959 patients who were eligible for analysis 17% had a S(p)O(2) < 90% and 6.6% a S(p)O(2) < 85%. Hypoxemia was not recognized in 82% of the patients in whom an assessment based on clinical grounds was carried out. Variables with an independent influence on hypoxemia and decrease of S(p)O(2) were as follows: saturation before induction of GA, body mass index, age, American Society of Anesthesiologists (ASA) physical status, difference between maximum and minimum inspiratory pressure, mode of ventilation, the choice of opioid and muscle relaxant as well as the use of nitrous oxide. Patient-dependent risk factors had the strongest impact on hypoxemia. In about 80% of the university hospitals neither PO nor supplemental oxygen is used during transportation of the patient from the OR to the PACU., Conclusions: The use of opioids and relaxants with short duration of action may have favorable effects on preventing hypoxemia and decreases of S(p)O(2). These measures will, however, not be sufficient to solve this problem because the highest risk factors for hypoxemia are patient-related. Despite knowing risk factors for oxygen desaturation, it is currently not possible to reliably predict which patients will become hypoxemic or have a decrease of S(p)O(2). Therefore, transportation of patients breathing room air from the OR to the PACU directly after GA without use of PO or supplemental oxygen seems to be questionable in terms of patient safety.

Background: In patients with COPD and isolated night time hypoxemia, oxygen administration has not shown any effects on life expectancy and the development of pulmonal arterial hypertension. The aim of the present pilot study was to investigate the influence of nocturnal oxygen therapy on the quality of life in daytime normoxemic COPD patients with nocturnal oxygen desaturations., Patients and Methods: 19 patients with COPD, in a stable phase of the disease without need for oxygen supplementation under rest (PaO2 62.7 +/- 4.9 mmHg) and nocturnal hypoxemia (t90 = 55.5 +/- 33.4 % of registration time, mean SaO2 89.8 +/- 1.9 %, minimal SaO2 81.1 +/- 4.8 %) were randomly assigned to either oxygen or placebo treatment, both generated by identical concentrator devices. Each treatment period lasted 6 weeks, after six weeks a cross-over was performed by a technician. Quality of life was assessed before and at the end of each treatment period by the SF-36, Nottingham Health Profile and Saint George's Respiratory Questionnaire., Results: Significant differences for the comparison of placebo and verum were only seen for the dimension sleep (NHP), all other dimensions showed no differences between placebo and oxygen. However, both placebo and oxygen improved the majority of the quality of life items significantly., Conclusions: The prescription of supplemental oxygen in COPD patients with isolated nocturnal hypoxemia in the present pilot study is not able to improve the quality of life within 6 weeks after initiation of therapy. It cannot, therefore, be generally recommended, but may be indicated in patients with a documented improvement of sleep quality.

Background and Objective: In patients with obstructive sleep apnea syndrome (OSAS) there is an increased comorbidity of internal diseases such as hypertension, coronary heart disease, chronic obstructive pulmonary disease and endocrine diseases. We analyzed prospectively frequency and consequences of pathological results in routine examinations of internal medicine in sleep laboratory., Methods: 250 patients with OSAS underwent routine bodyplethysmography, blood- gas analysis, electrocardiogram and laboratory studies after anamnesis and clinical examination. Prior to this we indicated, whether we based on history and physical examination deemed any of these examinations necessary. Frequency and kind of pathological results as well as the consequences were analyzed., Results: 129 results of bodyplethysmography and blood-gas analysis were pathological (51.6 % of all investigations), most frequently hypoxemia (22 %) and obstructive pattern (16.4 %). Further steps were necessary in 19 patients (7.6 %); the indication was seen before in 13 patients, therefore 6 results with consequences (2.4 %) were not expected. Laboratory studies were abnormal in 133 patients (53.2 % of all investigations), most of them hyperglycaemia (26.8 %) and elevated liver enzymes (20.4 %). 29 results (11.6 %) had consequences, of which 16 (6.4 %) were not expected. 82 electrocardiograms were pathological (32.8 % of all investigations), presenting most frequently as coronary heart disease (21.2 %). Further steps were necessary in 5 patients (2 %), while that was not expected in 3 patients (1.2 %)., Conclusions: Routine examinations of internal medicine in patients with OSAS frequently present pathological results, which seldom have further consequences. As most of the important results can be predicted by history and clinical investigation, pathological by chance diagnoses are rare. With the exception of blood sugar tests routine examinations for patients with OSAS should be considered critically.

The pathogenesis of apnoea in preterm infants is poorly understood. Thus, it is yet unknown (1) whether the descriptive distinction between "central", "obstructive" and "mixed" apnoeas is also reflected by differences in their respective pathogenesis, (2) how and where the airway closure occurs during the so-called "obstructive" apnoeas, (3) whether "central" apnoeas do indeed result from a disturbance in the central nervous control of breathing, as implied by their name, or whether they constitute a reflex response to a disturbance in the periphery of the lung, and (4) whether non-apnoeic mechanisms contribute to the hypoxaemia so frequently observed during these episodes. This paper summarises the present knowledge regarding the above issues. It also reviews the current definitions for apnoea, bradycardia and hypoxaemia in preterm infants, describes indications for intervention, and discusses some strategies aimed at preventing these episodes.

Arterial oxygen saturation (SaO2) was continuously measured using a pulse oximeter in 214 spontaneously breathing adult patients in a recovery room. Hypoxaemia was defined as an SaO2 of 90% or below. The patients were divided into three groups: in group I (n = 83) monitoring was started immediately after arrival in the recovery room, just before oxygen therapy was begun. The patients in group II (n = 106) were observed during and after oxygen therapy. Patients in group III (n = 25), most of whom had regional anaesthesia, were not treated with oxygen in the recovery room. RESULTS. Clinically unexpected hypoxaemia occurred in all three groups: hypoxaemia was observed in 32.6% of patients before oxygen administration (group I). Under oxygen therapy SaO2 was normal in 99.4% of the patients; however, in 30.2% of patients hypoxaemia recurred after oxygen had been discontinued (group II). Hypoxaemic periods were seen in 24% of patients in group III. CONCLUSION. The results indicate the necessity of oxygen administration during transport and in the early postoperative period to all patients. Even during and after regional anaesthesia or brief general anaesthesia, oxygen administration appears to be indicated. Monitoring of SaO2 with a pulse oximeter has become an increasingly standard procedure in modern anaesthesia and should be mandatory.

Lung function measurements in 472 dust-exposed workers have shown, that bronchial obstructions prevail, irrespective of the occurrence and severity of silicosis. Severe obstructions were growing more frequent with increasing duration of exposure. The incidence rate of arterial hypoxia at rest also increased with increasing duration of exposure. Regardless of the duration of exposure to dust there was pulmonary hypertension at rest in about 15 per cent of the patients examined. It is not unlikely that a correlation exists between the duration of exposure and the incidence rate of exercise-induced pulmonary hypertension (in about 40 per cent), in which arterial hypoxia concerning the functional aspect of increasing precapillary resistance (Euler-Liljestrand mechanism) seems to be of paramount significance.