Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Childhood cataracts

OBJECTIVE

The aim of this study was to determine the surgical outcome of childhood cataracts.

METHOD

Between 1990 and 1997, 137 patients less than 10 years of age (181 eyes) underwent cataract surgery at the Royal Alexandra Hospital for Children/New Children's Hospital. Data were collected retrospectively from medical records and supplemented with data from referrng ophthalmologists.

RESULTS

In the majority of patients (53.0%), the cause of cataract was unknown. Sixty-two patients (45.3%) had bilateral and 75 patents (54.7%) had unilateral cataracts. In 84 patients (107 eyes: 59.1%), the onset of visually significant cataract was estimated to be before the age of 2 years. Reliable postoperatve visual acuity (VA) was obtained in 150 eyes from 116 patients. The mean LogMAR VA was 0.71 +/- 0.55 in bilateral cataracts and 1.17 +/- 0.68 in unilateral cataracts. Visual acuity was poor (LogMARVA > 1.0) in 71.8% of unilateral cataracts (compared to 27.9% in bilateral cataracts, P < 0.0001), and in 64.9% when onset was ess than 2 years (compared to 22.4% in later onset cataract, P < 0.0001). Posterior capsular opacity requiring laser or surgical removal was noted in 40 patients (44 eyes; 24.4%). Other complications included raised intraocular pressure in six patients (seven eyes: 3.7%), displaced intraocular lens or iris capture in 11 patients (12 eyes; 6.6%), ectopic pupil in five patients (five eyes; 2.7%), and severe inflammation in eight patients (12 eyes; 6.6%). There was cosmetically significant esotropia or exotropia in 24 patients (23 eyes; 12.7%).

CONCLUSION

The prognosis for vision was significantly poorer in unilateral and earlier onset cataract. The importance of early diagnosis, prompt treatment and vigilant postoperative follow up in this subgroup cannot be overemphasized.

Evaluation of oculokinetic perimetry

BACKGROUND AND METHOD

Oculokinetic perimetry (OKP) was performed on 98 patients (187 eyes) using the Damato 26-point glaucoma screening chart. Results were compared with those obtained from a 24-2 full threshold test on a Humphrey Field Analyser (HFA).

RESULTS

In its ability to detect pathology in individual eyes, OKP had a sensitivity of 75.0% and a specificity of 71.4%. To detect glaucoma, OKP demonstrated a sensitivity of 86.0% and a specificity of 56.1%. The number of OKP defects detected increased with increasing HFA mean defect and corrected pattern standard deviation. Whereas moderate and severe field defects were almost always detected, smaller and shallower glaucoma defects were often missed.

CONCLUSION

The fall in sensitivity and specificity of the OKP chart in identifying milder glaucomatous field defects diminishes its value as a screening test. However, its introduction into wider use in the community may increase awareness of glaucoma amongst general practitioners and members of the public, and help to detect previously undiagnosed glaucoma with moderate to severe damage. A normal OKP finding does not exclude the presence of early glaucoma. Combined with ophthalmoscopy, OKP may improve glaucoma detection rates amongst non-ophthalmologists.

Can the current oculokinetic perimetry chart be improved?

BACKGROUND/METHOD

Several studies have been performed to determine the effectiveness of oculokinetic perimetry (OKP) as a glaucoma screening test. In a previous study, we noted that OKP sensitivity and specificity was lower in mildly defective fields compared with moderately or severely, defective fields. In this study, we looked at visual fields with 'glaucomatous' defects. The visual field was divided into zones and points. The frequency of glaucomatous defects and visual sensitivity levels in these areas was recorded. The sensitivity and specificity of OKP to detect these defects were analysed.

RESULTS

Ninety-six glaucomatous fields from 57 subjects were assessed. An OKP chart testing the 8 to 16 degrees of eccentricity, and an extended nasal region, would cover all the defective fields present in this study. The 12-16 degree eccentricity zone has the best sensitivity (75%) and specificity (65%). Points within the nasal, inferior temporal and 8-12 degree eccentricity might be less sensitive, but 11 (11.5%) fields had defects only in these areas. Zonal and point sensitivities and specificities were very similar suggesting that fewer points could be used in each zone with similar results. Many of the eyes with false-negative OKP results had Humphrey Field Analyser visual sensitivity levels in the 10-18 dB range (i.e. associated with a mild or moderate defect). Decreasing the target stimulus might increase the detection rate of these milder defects; however, it might also increase overall false-positive rates. Our proposed experimental chart consists of two to four test points in each quadrant within the 12-16 degree of eccentricity, five within the 8-12 degree zone and two in the nasal region, and a central 1 or 1.5 mm black target.

CONCLUSION

Analysis of results with modifications of the testing device may permit the OKP chart to achieve its full potential.

Comparison of extracapsular and phaco-emulsification cataract extraction techniques when combined with intra-ocular lens placement and trabeculectomy: short-term results

BACKGROUND METHODS: Fifty patients who had undergone combined extracapsular cataract extraction (ECCE), intra-ocular lens (IOL) placement and trabeculectomy (ECCE-trab) and 50 who had undergone combined cataract phaco-emulsification, IOL placement and trabeculectomy (phaco-trab) were reviewed over a period of 12 months.

RESULTS

Postoperatively, intra-ocular pressure (IOP) in both eyes fell significantly (P < 0.005). Initially, IOP fell to roughly equal degrees (mean IOP being 14 mmHg at 3 months; P = 0.84). At 12 months, IOP in the phacotrab group was slightly lower than that in the ECCE-trab group (13.4+/-4.3 vs 15.4+/-4.4 mmHg, respectively; P = 0.0312). The number of pre-operative medications did not appear to affect outcome (P = 0.124). Visual recovery was approximately 3 months faster in the phaco-trab group. By 12 months there was little difference in visual acuity, with an average improvement of two Snellen lines (P = 0.68). The mean change in astigmatism was significantly less in the phaco-trab group (0.61+/-1.25 vs 1.39+/-1.46 D, respectively, P = 0.0063). Transient hypotony (IOP < 5 mmHg) was more frequent in the phaco-trab group (66 vs 32%, respectively; P < 0.002). The frequency of other complications was not significantly different between the two groups.

CONCLUSION

Both ECCE-trab and phaco-trab procedures are safe and effective. However, the phaco-trab procedure may have slightly improved IOP control, earlier visual recovery and less astigmatism.