Late postoperative nocturnal dips in oxygen saturation in patients undergoing major abdominal vascular surgery

Abstract

SummaryTwenty-four patients (23 male) who presented for aortic reconstructive surgery were studied with pulse oximetry on a pre-operative night and during the first five postoperative nights. Patients with five or more dips in oxygen saturation of greater than 4% (with a prompt recovery back toward baseline of 3% or more) per hour of monitoring were classified as having a significant abnormality of respiration. Pre-operatively, four of 24 patients ( I 7%) demonstrated such an abnormality. Postoperatively. 12patients (50%) met these criteria on at least one of the first five postoperative nights and six of these had two or more nights with severe episodic hypoxaemia. Frequent severe episodic dips in arterial oxygen saturation (to less than 85% saturation) occurred in the late postoperative period at a time when oxygen therapy would usually have been discontinued. Pre-opera five overnight pulse oximetry studies fail to predict the development of abnormal respiratory patterns in the postoperative period in the majority of patients. Key words Surgery; abdominal.Complications; postoperative hypoxaemia. Measurement techniques; pulse oximetry.Postoperative hypoxaemia may be persistent or episodic. Persistent hypoxaemia is usually the result of intrapulmonary complications which affect ventilation/perfusion relationships in the lung. Episodic hypoxaemia is usually the result of alterations in central neural respiratory drive to the respiratory and accessory respiratory muscles, which give rise to upper airway obstruction or periodic breathing patterns with central apnoea. These episodic phenomena occur almost exclusively during sleep.Several studies [ 1-31 have shown that abnormal patterns of respiration occur commonly in the early postoperative period. Catley et al. [ I ] in 1985 observed frequent episodic dips in oxygen saturation in patients who received an intravenous infusion of morphine during the first 16 h after surgery. These episodes, which occurred only while patients were asleep, were associated with both central and obstructive apnoeas. A recent study in patients undergoing major abdominal surgery [2] has shown that episodic dips in arterial oxygen saturation occur during the second as well as the first night after surgery. These studies reflect respiratory patterns in the relatively early postoperative period. However, little is known regarding the incidence, duration and severity of episodic hypoxaemia during the late postoperative period when supplementary oxygen has normally been discontinued. Furthermore, the clinical significance of such episodes in the generation of morbidity in the postoperative period, particularly in patients at risk from ischaemic heart disease, is unexplored.The aim of the present study was to document, in patients undergoing major abdominal vascular surgery, the pre-operative incidence of nocturnal episodic dips in arterial oxygen saturation, and to compare this with the incidence and severity of episodic nocturnal hypoxaemia occurring during the first five postoperative nigh...

High STOP-Bang score indicates a high probability of obstructive sleep apnoea

“…OSA patients are known to have a higher incidence of difficult intubation, 18 postoperative complications, 1920 increased intensive care unit admissions, 7 and greater duration of hospital stay. 21 Memtsoudis and colleagues 9 found that OSA was associated with a significantly higher incidence of pulmonary complications.…”

Postoperative complications in patients with obstructive sleep apnea: a retrospective matched cohort study

“…18 A high incidence of early and late postoperative nocturnal hypoxemic episodes in healthy patients undergoing surgery has been reported in a number of studies. [19][20][21] However, the currently available literature on the occurrence of perioperative respiratory complications among surgical patients with OSA is too limited to make any major correlations. The objective of this study was to test the hypothesis that OSA is a risk factor for the development of postoperative complications.…”

Perioperative Care of Patients with Obstructive Sleep Apnea

“…Therefore, alternative screening tools have been tested to assess for the severity of sleep-disordered breathing preoperatively. In their study using preoperative overnight oximetry in 24 patients, Reeder et al [10, Class II]. demonstrated “significant abnormalities of respiration” (SARs) postoperatively in all patients with preoperative SARs.…”